Research Article, Title: Chest Wall Strapping dilates airways and increases airway homogeneity in COPD

Research Article, Title: Chest Wall Strapping dilates airways and increases airway homogeneity in COPD | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Research Article, Title: Chest Wall Strapping dilates airways and increases airway homogeneity in COPD Michael Eberlein, Iliya Amaza, Eric Abston, Hassan Sajaad, Melissa. L. Bates This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8492362/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Chest wall strapping (CWS) is a technique that restricts the chest wall to induce breathing at lower lung volumes. CWS increases lung elastic recoil and expiratory airflows. In computer tomography imaging studies CWS dilates small airways in healthy and COPD-subjects. Dynamic-dysanapsis describes the concept of airway dilation via interdependence of airways and lung parenchyma from CWS induced increase in lung elastance. The time course of CWS induced dynamic-dysnapsis is not defined. Volumetric capnography and plethysmography allow for repeated measurements of the lung structure function relationship. We hypothesized that CWS causes an increase in dead space of COPD-subjects via CWS induced increase in airway dimensions. Secondly, we hypothesized that CWS increases airway homogeneity and that these effects last for a period after removal of CWS. Methods After performing baseline measurements (ventilation parameters, plethysmography, and volumetric capnography) participants with COPD (n = 5) and healthy, sex-matched controls (n = 5) underwent CWS. Measurements were repeated every 15 minutes for one hour following CWS. After CWS-removal measurements were repeated every 15 minutes for an additional hour. We related anatomic dead space, alveolar dead space, V D /V T , and slope of the capnogram to lung volume and tracked their changes over time. Results Moving from unstrapped to the CWS and to post-CWS condition, we saw an overall increase in the anatomic dead space (a surrogate with the size of the airway tree) for both groups with CWS and post-CWS (p = 0.001). The capnographic slope is an indicator of airway uniformity. Post-CWS had a significant effect on both groups causing a decrease in the slope of the capnogram to lung volume ratio, showing a significant increase in airway homogeneity (p = 0.03). Conclusion CWS dilates airways quantified by the increase in dead space. The increase in airway homogeneity persists at least 45 minutes after strapping is removed. This indicates lasting benefits of CWS on airway function. The dilatation of airways and the improvement in airway homogeneity during and after CWS could facilitate enhanced delivery of inhaled therapies in COPD. CWS should be further investigated as a novel non-pharmacological treatment for COPD. Chest Wall Strapping Airway parenchymal interdependence Dysanapsis COPD Figures Figure 1 Figure 2 Figure 3 BACKGROUND Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality globally [ 1 , 2 ]. COPD is characterized by progressive airway obstruction associated with the lung’s inflammatory response to noxious particles or agents, like cigarette smoke and has two major components: emphysema and chronic bronchitis [ 3 , 4 ]. Together, airway narrowing and loss of airway traction caused by alveolar destruction contribute to airway collapse and air trapping that is associated with decreased exercise tolerance and diminished quality of life [ 4 ]. Airway dysfunction and air trapping are present even in patients with relatively mild disease and progress over time [ 5 ]. Airways ≤ 2 mm are particularly vulnerable to collapse in these patients [ 6 ]. Chest wall strapping (CWS) is a historical physiological technique that has recently been shown to have possible relevance to the diagnosis and treatment of lung disease [ 7 – 11 ]. CWS restricts the chest wall to induce breathing at low lung volumes [ 7 ]. CWS increases lung elastic recoil and expiratory airflows [ 7 – 9 ]. Our group previously evaluated the lung structure function relationship in COPD before and after CWS, using pulmonary function studies and computed tomography [ 9 – 11 ]. CWS induced a 316% improvement in expiratory airflow and a 79% increase in the number of detectable airways small airways ≤ 2 mm in subjects with COPD [ 9 ]. Dynamic-dysanapsis describes the concept of airway dilation via interdependence of airways and lung parenchyma from CWS induced increase in lung elastance [ 9 – 11 ]. This suggests that CWS may be clinically useful in improving small airway function and possibly recruiting collapsed airways. However, there are several unanswered questions that are important in understanding the possible therapeutic utility of CWS. Specifically, little is known about the time course of airway recruitment during CWS and it is not known whether there is any persistent benefit to airways recruitment after removal of the chest wall strap. While essential in establishing the initial physiology of small airways recruitment by CWS in COPD, computed tomography requires radiation exposure and multiple repeated scans to establish a time course are not feasible. Typical computed tomography studies of the lung deliver 0.15 mSv of radiation energy, but even very low radiation doses (0.1–150 mSv) are associated with an increased lifetime risk of cancer [ 12 ]. Volumetric capnography is a single breath gas washout technique that utilizes the profile of exhaled CO 2 to derive information about the airway and alveolar dead spaces and heterogeneity of the distal airways. Experimentally, volumetric capnography is similar to clinical capnography, with the added requirement that measurements be made at controlled flow rates and lung volumes so that they can be compared between conditions and over time [ 13 – 15 ]. Members of our group have used volumetric capnography previously to evaluate airways volume and heterogeneity at functional residual capacity after air pollution exposure [ 16 , 17 ]. The airways are tractioned by the parychema and airway diameter is highly dependent on lung volume [ 18 ]. Coupling volumetric capnography with plethysmography allows for capnographic estimates of dead space volume and heterogeneity to be made at multiple lung volumes and the full lung structure-function relationship to be derived. We have published detailed methodology on the combined use of these techniques [ 14 ]. The purpose of this study was to quantify the lung structure-function relationship in COPD before, during, and after CWS. We hypothesized that CWS would induce an immediate improvement in airway volume and heterogeneity that would cease upon removal of CWS. This method allows for the comprehensive interrogation of the effects of CWS over extended time periods and lung volumes. We specifically investigated the changes in airway volume (i.e., dead space) attributed to application and removal of strapping. An increase in dead space is attributed to an increase in airway dimensions and airway recruitment. A decrease in dead space would indicate a decrease in airway dimensions. We hypothesized that CWS will cause an increase in dead space of COPD patients because of a CWS induced increase in airway dimensions. Secondly, we measured effects of CWS on airway uniformity, and we hypothesized that CWS increases airway homogeneity. METHODS Study cohort and overall design . Male participants with COPD were recruited from the University of Iowa COPD-Gene cohort (n = 5) and healthy, sex-matched controls (n = 5) were recruited from the general population at the University of Iowa. COPD subjects participated in the previous CWS lung imaging study [ 9 ]. Inclusion criteria for participants with COPD included a documented clinical history of COPD, FEV 1 /FVC < 0.70 on the day of study, and willingness to tolerate the CWS device. Control participants reported no clinical history of lung or cardiovascular disease, had a normal FEV 1 /FVC on the day of study, and were also willing to tolerate the CWS device. All experiments were performed in accordance with the Declaration of Helsinki and participants provided informed consent prior to participation. This study was approved by the Institutional Review Board of the University of Iowa. Participants visited the laboratory on a single occasion, and the experimental design was the same for both groups. Anthropometric data, including height, weight, age, COPD medical history, and ethnicity were collected. Lung volumes and pulmonary function were assessed using standard clinical plethysmography and spirometry. Prior to CWS, participants sat at a custom station for the measurement of baseline ventilation and volumetric capnography. A piezo-electric transducer was placed around the index finger to record heart rate (TN1012/ST, AD Instruments, Colorado Springs, CO). One minute of stable, baseline ventilation data was collected. They were then coached to perform the volumetric capnography maneuver. After performing these baseline measurements, participants were fitted with the chest wall strap used previously [ 9 ]. Briefly, each individual was coached to empty their lungs to residual volume while the strap was tightened around the chest. Baseline ventilation, plethysmograpy, and capnography was repeated every 15 minutes for one hour following application of the strap. The strap was then removed, baseline ventilation was assessed, and volumetric capnography measurements were repeated every 15 minutes for an additional hour. It is hypothesized that CWS mechanistically increases elastic recoil by the altering the air-fluid interface of the lung and that inhalation to total lung capacity interferes with these effects [ 8 , 19 ]. Because spirometry and plethysmography require deep inhalation that might interfere with our ability to measure the time course of CWS-induced changes in airways function, plethysmography was not performed again after removal of the chest wall strap. After an hour of measurements post-CWS capnography measurements, participants were coached to take a total lung capacity breath and capnography was repeated. Chest Wall Strapping Procedure. A commercially available flotation vest (Stearns adult life vest) was placed around the chest and upper abdomen. Participants were coached to exhale to residual volume and the vest was tighten to reduce the total lung capacity to ~ 70% of baseline [ 9 ]. Spirometry and plethysmography. Spirometry and plethysmography was performed using commercially available equipment (V62J, Vyaire Medical, Mettawa, IL) in the University of Iowa Institute for Clinical Research in accordance with current consensus statements [ 20 , 21 ], as we have described previously [ 14 ]. At least three plethysmographic maneuvers were completed until two values of functional residual capacity (FRC) within 5% were obtained. Where appropriate, expiratory flow rates and lung volumes were compared to the NHANES and Goldman and Becklake predictive equations [ 22 ]. Ventilation and volumetric capnography. For measures of baseline ventilation, participants donned noseclips and were coached to sit upright, place their feet on the floor, insert the mouthpiece, and breathe quietly. The real time profiles of exhaled tidal volumes and carbon dioxide were observed by an investigator and one minute of data was collected when tidal volume and end tidal carbon dioxide were deemed to be stable. Expiratory flow rates and carbon dioxide concentration were measured using commercially available equipment as described previously [ 14 – 17 ], including a heated pneumotach set to 37°C and a rapidly responding gas analyzer. The same equipment was used for volumetric capnography measurements and the principles and application of our technique have been described previously [ 14 – 17 ]. Step-by-step instructions to reproduce the technique, calibration information, and the analysis macro have been published and are freely available [ 14 ]. Briefly, participants were coached to follow a pattern displayed on a computer screen to generate two pairs of two-breath maneuvers at targeted inhalation and exhalation flow rates (250 mL/s) and durations (3s for the first breath and 5s for the second breath, see example as described in detail at [ 14 ]). Measurements were made at different initial lung volumes by coaching participants to vary the volume of the lung immediately before the initiation of the maneuver. At the end of the maneuver, participants were coached to sigh with an open glottis and lung volume where the expiratory flow reached zero was set as FRC. Initial lung volumes were referenced to this point. Based on previous inter-maneuver variability studies [ 14 ], a total of 8 maneuvers were collected at each time point Data Analysis . Data were acquired in LabChart (AD Instruments, Colorado Springs, CO). Carbon dioxide and flow data were processed in an excel-based macro to generate volumetric capnograms from which anatomic dead space and the slope of the alveolar plateau were determined. and plethysmograph data, we extrapolated using an excel MACRO program the following values: anatomic dead space, alveolar dead space, VD/VT, and slope (CO 2 /L). We also measured lung volume, heart rate, ETCO 2 , and peak sigh flow. All graphing was done in the 2019 edition of GraphPad Prism. Repeated measure analysis of covariance (ANCOVA) tests were run on Minitab 18 to find differences between the experimental groups, volumes measured, CWS and post-CWS conditions, and relationships between these categories. The ANCOVA test was chosen as lung volume is a continuous measure. A more in-depth integration and analysis of both capnography and plethysmography data is described in detail in our previous publication [ 14 ]. Statistical significance was set at a priori p < 0.05. RESULTS Anthropometric data for the Control and COPD group are shown in Table 1 . COPD subjects were older than controls (63 ± 2.2 years vs. 32 ± 1.0 years, p < 0.001). There was no difference in height, weight, or BMI. The CT-scans revealed emphysema as the primary phenotype for 4 of 5 COPD subjects. The remaining subject’s primary COPD-phenotype was chronic bronchitis. As expected, baseline plethysmography and spirometry were different, consistent with the COPD group’s diagnosis (Table 1 ). Residual volume (RV) and functional residual capacity (FRC) were higher in the COPD group (p < 0.05). Baseline Capnography Because of the well-established relationships between airway resistance and lung volume we related capnographic parameters to lung volume. As predicted airway volume was related to lung volume in both groups (Fig. 1 A). There was a difference in anatomic dead space between the two groups, with COPD subjects on average having lower anatomic deadspace (p = 0.039). Alveolar dead space was correlated with lung volume (p < 0.001) and there was a group by volume interaction (p = 0.024, Fig. 1 B). The slope of the capnogram (CO2/L) in relationship to lung volume showed more airway heterogeneity and in COPD subjects compared to normal subjects at any lung volume (p = 0.003, Fig. 1 D). The slope of the capnogram (CO2/L) differed between the control and COPD groups (p < 0.001), with a correlation between slope and lung volume (p < 0.001), as well as a group by volume interaction (p = 0.003). Experimental CWS Capnography To track the change in the relationship between airway resistance and lung volume we related anatomic dead space, alveolar dead space, V D /V T , and slope of the capnogram (CO2/L) to lung volume and tracked their change over time. (Fig. 2 A, 2 B, 2 D, p < 0.001 and Fig. 2 C, p = 0.006). Overall, the control subjects had smaller anatomic dead spaces over the course of the experiment (p < 0.001, Fig. 2 A). Moving from unstrapped to the CWS and to post-CWS condition, we saw an overall increase in the anatomic dead space for both groups with CWS and post-CWS. (p = 0.001). The absence of a group by strapped relationship indicated that both groups respond similarly to strapping. There was a difference in alveolar dead space between the two groups (p < 0.001, Fig. 2 B). The group by strapped effect (p < 0.001) indicated that the transition from the CWS condition to post-CWS condition had markedly different impacts on the alveolar dead space. The COPD group showed an immediate increase in the alveolar dead space. The control group showed an opposite effect with a small decrease in the alveolar dead space. Over the course of the experiment, the relationship of total dead space to tidal volume (V D /V T ) remained larger in the control group (p < 0.001, Fig. 2 C). Strapping did not have an effect on V D /V T for either experimental group. Additionally, because of the lack of a group by strapped relationship, both control and COPD groups V D /V T reacted to CWS and post-CWS in the same way. The capnographic slope is an indicator of airway uniformity. The slope versus time can be seen in Fig. 2 D. The percent CO 2 to absolute lung volume differs between the groups (p < 0.001). Due to the lack of a group by strapped relationship, both groups reacted to CWS and post-CWS in the same way. Post-CWS had a large effect on both groups causing a decrease in the slope to lung volume ratio (p = 0.0303). Additional Experimental Measures To better understand the physiological changes occurring with CWS, we tracked several other measurements over the course of the experiment. The control group showed much higher heart rates throughout the testing (p < 0.001, Fig. 3 A). There was an elevated response in heart rate for the CWS condition compared to the post-CWS condition, (p < 0.001). The control group exhibited higher end-tidal CO 2 measures for the entire experiment (p < 0.001, Fig. 3 B). We saw a differing correlation between the COPD and control groups and the CWS and post-CWS condition for end-tidal CO 2 (p < 0.001). However, we saw no overall difference between the CWS and post-CWS conditions. Peak sigh flow measurements were different between control and COPD groups (p < 0.001, Fig. 3 C) and different between overall CWS and post-CWS conditions (p < 0.001). The was no overall correlation between the groups and strapped conditions, meaning the two groups responded similarly to strapping. They showed a slight increase in peak sigh flow with the addition of strapping, and persistence in that increase for the remainder of the experiment. Figure 3 D shows that COPD patients breath at much higher lung volumes than control patients over the entire experiment, with an increase in Post-CWS conditions (p < 0.001) DISCUSSION In this study we examined the time course of CWS on the lung structure function relationship in COPD and control subjects. When analyzed in the context of absolute lung volume, CWS increased anatomic dead space and airway uniformity in COPD and normal controls. The increased anatomic deadspace is likely from an increase in small airway dimensions. Dynamic-dysanapsis describes airway dilation via airway-lung interactions mediated by increased elastic recoil induced by CWS. In addition to increased airway dimensions, CWS was associated with improved airway homogeneity. These observations and especially the persistence of the CWS effect after the intervention suggest the potential of using CWS as a novel therapeutic intervention for COPD patients to improve the lung structure function relationship. Volumetric capnography can evaluate the impact of CWS on dead space. For both COPD and control patients we saw an increase in anatomic dead space due to strapping. Post-strap removal we saw this increase in anatomic dead space remained. This is consistent with our hypothesis that predicted an increase in dead space due to the larger number of small airways being held open in response to strapping. When looking at alveolar dead space in the control group, we again saw a small increase in dead space with CWS and a small decrease in the post-CWS condition. However, in the COPD group we saw an increase in the alveolar dead space with the removal of the strap. This indicated that in COPD patients, the effect of strapping persists after the straps have been removed. Likely more small airway remain dilated, with more alveoli available for gas exchange. We see the effect of airway dilation in the peak sigh flow measures over time for the COPD patients. There is a persistent increase in flow after CWS that was maintained after the strapping was removed. This indicated CWS allows COPD patients to move air out of their lungs more easily, likely due to the dilation of the small airways. The control patients show little change in the peak sigh flow over time. We suspect this is because it is necessary for COPD patients to breath at larger lung volumes as they have larger functional residual capacity’s (FRC). Thus, if they are breathing at larger lung volumes and get restricted, there will be a greater impact on peak sigh flow than the controls who have lower FRC’s. The ratio of total dead space to tidal volume (V D /V T ) is higher in the control vs COPD individuals. This difference can be accounted for considering that V D /V T the includes the total dead space of the individual, that means the sum of both anatomic dead space and alveolar dead space. When adding the anatomic and alveolar dead spaces for the control group we found an increase in both anatomic dead space and alveolar dead space with CWS. Thus, they added to an overall increase. Furthermore, Fig. 3 D shows that control individuals breath at much lower lung volumes than the COPD patients. So, when the two larger values are divided by smaller volume, we see a larger ratio for the control overall. The lower V D /V T ratio the COPD patients can also be accounted for by the addition of the two dead spaces to get total dead space. We see an increase in anatomic dead space with strapping opposed by the increase in alveolar dead space with strapping. This balances out to a lower average value for the CWS condition. This average value is divided by larger average lung volumes for COPD patients (Fig. 3 D). Thus, the ratio is smaller overall for COPD patients throughout the experiment. Green originally described dysanapsis as an anatomic mismatch between airway size and lung volume that arose because of developmental heterogeneity [ 23 ]. Dynamic-Dysanapsis describes changes in the lung structure function relationship: Increased lung elastance with CWS dilates airways via interdependence [ 11 ]. We have previously shown dynamic-dysapasis with CWS in a porcine model [ 11 ]. Dynamic-dysanapsis appears to be a compensatory mechanism to preserve pulmonary gas exchange efficiency by airway dilation when the lung operates at lower volumes. Transplanting an oversized lung allograft into a smaller recipients chest has similarities to CWS [ 7 ]. We reported supranormal expiratory airflows associated with oversized lung allografts [ 24 ]. Oversized allografts had higher FEV 1 /FVC ratios (0.895 ± 0.13 vs 0.821 ± 0.13, P < 0.01) and a lower risk of bronchiolitis obliterans syndrome (BOS) than undersized allografts [ 25 ]. BOS is characterized by progressive scarring and narrowing of the small airways (bronchioles) and is the major cause of death after lung transplantation. We have demonstrated that oversized allografts are associated with improved survival following lung transplantation [ 26 , 27 ]. Dynamic-dysanapsis via CWS was demonstrable in a CT imaging study of COPD subjects. CWS increased the mean number of detectable airways with a diameter of ≤ 2 mm by 79% (59 ± 19 vs. 104 ± 16, P = 0.01) in subjects with COPD [ 9 ]. The slope of the capnogram evaluates the heterogeneity of the airway. With an increased slope corresponding to a larger difference in the airway uniformity. For both control and COPD patients we saw a decrease in slope due to strapping and a further decrease with the removal of strapping. Thus, we see chest wall strapping improves the homogeneity of the airways with persistent effects into post-CWS condition. These results indicate that CWS could help alleviate air trapping that occurs in COPD patients and dynamic hyperinflation, as their airways become more homogenous. Our additional experimental measures can be used to evaluate the safety of CWS as an intervention for COPD individuals. A concern when restricting the chest wall is the potential for the increased work of breathing it may cause. Increased work of breathing could limit ventilation, leading to an increased ETCO 2 . Our data (Fig. 3 B) for both the COPD and control groups show maintenance of ETCO 2 compared to baseline with the addition of CWS. Furthermore, we see a decrease once the CWS is removed. So, we can conclude that CWS does not cause a clinically significant increase in work of breathing in subjects with GOLD stage I-III COPD. Limitations Limitations of our study could include the small sample size, subjects were male and mostly emphysema-predominant GOLD I–III. A more widespread study across the phenotypes of COPD to confirm our results would be beneficial in further defining how CWS effects the lung structure function relationship. We demonstrated dynamic-dysnapsis, increased lung elastance with CWS dilates airways via interdependence, in a porcine model and in larger cohort studies of recipients of oversized lung allografts [ 11 , 24 , 25 ]. This suggests that dynamic-dysnapsis could be a canonical mechanism to preserve pulmonary gas exchange efficiency by airway dilation when the lung operates at lower volumes. Another limitation is the nature of the tests themselves. Pulmonary function tests can be variable within an individual and a longitudinal study over several months would be beneficial to see if the effects of CWS continue to be apparent with multiple applications of the device. Increasing anatomical dead space was interpreted as airway dilation/recruitment. While we cannot rule out alternative explanations such as shifts in operating lung volumes, or differences in mouthpiece dead space handling the same subjects had CT imaging evidence of airway dilation in a previous study [ 9 ]. CONCLUSIONS In confirmation of previous imaging studies [ 9 ] we have shown that CWS does dilate airways quantified by the increase in dead space seen for COPD patients. Furthermore, the increase in airway homogeneity persists at least 45 minutes after strapping is removed. This indicates lasting benefits of CWS on the lung structure function relationship in COPD. Overall, we conclude that CWS should be further investigated as a potential nonpharmacological intervention in COPD patients to improve small airway function. In future studies we plan to test if the post CWS effect can increase effectiveness of inhaled medications such as albuterol. The dilatation of airways and the improvement in airway homogeneity during and after CWS could help for inhaled therapies to be delivered more effectively. Abbreviations CWS Chest wall strapping COPD Chronic obstructive pulmonary disease CT Computer Tomography FEV 1 forced expiratory volume in 1 second FRC functional residual capacity FVC forced vital capacity PFT pulmonary function studies Declarations Ethics approval and consent to participate All experiments were performed in accordance with the Declaration of Helsinki and participants provided informed consent prior to participation. This study was approved by the Institutional Review Board of the University of Iowa. Consent for publication: Yes Availability of data and materials De-identified data and analysis code are available from the corresponding author upon reasonable request and subject to institutional policies. Competing interests The authors have no conflicts to declare. Dr. Bates is Founder and CEO of LSF Medical Solutions whose work overlaps topically with the content of the manuscript. She received no reimbursement for her participation in this project. Funding This work was supported by a PILOT grant from the Institute for Clinical and Translational Science at the University of Iowa via the National Center for Advancing Translational Sciences Grant UL1-TR-000442 (M. Eberlein). Authors' contributions ME, IA, HS, and MLB designed the study, ME, HS, IA, and MLB collected data, ME, HS, IA, and MLB analyzed and interpreted the data, ME and MLB drafted the manuscript, ME, HS, IA, EA and MLB edited and approved the final manuscript Acknowledgements Harold Winnike, Elizabeth Pritchard, Caylie Sheridan and Erik P. Tomasson participated in aspects of this study and their contributions are appreciated. References Naeem S, Wang F, Mubarak R, et al. Mapping the Global distribution, risk factors, and temporal trends of COPD incidence and mortality (1990–2021): ecological analysis. BMC Med. 2025;23:210. Owusuaa C, Dijkland SA, Nieboer D, et al. Predictors of mortality in chronic obstructive pulmonary disease: a systematic review and meta-analysis. BMC Pulm Med. 2022;22:125. https://doi.org/10.1186/s12890-022-01911-5 . Wachami AL, Guennouni N, Iderdar M. Estimating the global prevalence of chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis. BMC Public Health. 2024;24:297. https://doi.org/10.1186/s12889-024-17686-9 . Scichilone N, Whittamore A, White C, et al. The patient journey in Chronic Obstructive Pulmonary Disease (COPD): a human factors qualitative international study to understand the needs of people living with COPD. BMC Pulm Med. 2023;23:506. https://doi.org/10.1186/s12890-023-02796-8 . Kim T, Kim Y, Bak SH, et al. Longitudinal parametric response mapping on CT in assessing functional small airway disease and emphysema in COPD. Sci Rep. 2025;15:37221. https://doi.org/10.1038/s41598-025-21015-4 . McDonough JE, Yuan R, Suzuki M, et al. Small-Airway Obstruction and Emphysema in Chronic Obstructive Pulmonary Disease. N Engl J Med. 2011;365:1567–75. 10.1056/NEJMoa1106955 . Eberlein M, Schmidt GA, Brower RG. Chest wall strapping. An old physiology experiment with new relevance to small airways diseases. Ann Am Thorac Soc. 2014;11:1258–66. Stubbs SE, Hyatt RE. Effect of increased lung recoil pressure on maximal expiratory flow in normal subjects. J Appl Physiol. 1972;32:325–31. Taher H, Bauer C, Abston E, et al. Chest wall strapping increases expiratory airflow and detectable airway segments in computer tomographic scans of normal and obstructed lungs. J Appl Physiol. 2018;124:1186–93. Abston E, Eberlein M. Chest wall strapping in a porcine model: A model for the physiology of the oversized lung allograft. JHLT Open. 2025;8:100248. 10.1016/j.jhlto.2025.100248 . Abston E, Eberlein M. Chest wall strapping in a porcine model: Dynamic dysanapsis dilates airways for optimized function of the oversized lung. JHLT Open. 2025;9:100317. 10.1016/j.jhlto.2025.100317 . Pierce DA, Preston DL. Radiation-related cancer risks at low doses among atomic bomb survivors. Radiat Res. 2000;154:178–86. Baker LG, Ultman JS, Rhoades RA. Simultaneous gas flow and diffusion in a symmetric airway system: a mathematical model. Respir Physiol. 1974;21:119–38. Seymour M, Pritchard E, Sajjad H, Tomasson EP, Blodgett CM, Winnike H, Paun OV, Eberlein M, Bates ML. Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship. J Vis Exp 11, 2019. Taylor AB, Lee GM, Nellore K, Ben-Jebria A, Ultman JS. Changes in the carbon dioxide expirogram in response to ozone exposure. Toxicol Appl Pharmcol. 2006;213:1–9. Bates ML, Brenza TM, Ben-Jebria A, Bascom R, Eldridge MW, Ultman JS. Pulmonary function responses to ozone in smokers with a limited smoking history. Toxicol Appl Pharmcol. 2014;278:85–90. Bates ML, Brenza TM, Ben-Jebria A, Bascom R, Ultman JS. Longitudinal distribution of ozone absorption in the lung: comparison of cigarette smokers and nonsmokers. Toxicol Appl Pharmcol. 2009;236:270–5. West JB. Respiratory Physiology: The Essentials 8th Edition. Philadelphia: Wolters Kluwer, 2008, p. 208. Young SL, Tierney DF, Clements JA. Mechanism of compliance change in excised rat lungs at low transpulmonary pressure. J Appl Physiol. 1970;29:780–5. Wanger J, Clausen JL, Coates A, et al. Standardisation of the measurement of lung volumes. Eur Respir J. 2005;26:511–22. Culver BH, Graham BL, Coates AL, et al. Recommendations for a Standardized Pulmonary Function Report. An Official American Thoracic Society Technical Statement. Am J Respir Crit Care Med. 2017;196:1463–72. Goldman HI, Becklake MR. Respiratory function tests; normal values at median altitudes and the prediction of normal results. Am Rev tuberculosis. 1959;79:457–67. Green M, Mead J, Turner JM. Variability of maximum expiratory flow-volume curves. J Appl Physiol. 1974;37:67–74. Eberlein M, Permutt S, Brown RH, et al. Supranormal expiratory airflow after bilateral lung transplantation is associated with improved survival. Am J Respir Crit Care Med. 2011;183(1):79–87. 10.1164/rccm.201004-0593OC . Eberlein M, Permutt S, Chahla MF, et al. Lung size mismatch in bilateral lung transplantation is associated with allograft function and bronchiolitis obliterans syndrome. Chest. 2012;141(2):451–60. 10.1378/chest.11-0767 . Eberlein M, Reed RM, Maidaa M, et al. Donor-recipient size matching and survival after lung transplantation. A cohort study. Ann Am Thorac Soc. 2013;10(5):418–25. 10.1513/AnnalsATS.201301-008OC . Eberlein M, Reed RM, Abston E, et al. Sizing in lung transplantation: principles, practices and ideas for the future. JHLT Open. 2025;9:100304. 10.1016/j.jhlto.2025.100304 . Tables Table 1 Anthropometric characteristics of normal subjects and subjects with mild to moderate COPD (GOLD stages 1-3) Subject Age (yr) Height (cm) Weight (kg) BMI Primary CT scan phenotype TLC (L) RV (L) FRC (L) FEF 25−75% (L) FEV 1 (L) FEV 1 /FVC Control 1 32 175.3 58.9 19.2 N/A 6.49 1.77 2.97 2.63 (60) 3.62 (82) 73 (89) 2 33 172.0 83 28.1 N/A 8.07 2.01 2.82 3.77 (92) 4.67 (114) 77 (95) 3 32 187.9 88.4 25.0 N/A 7.61 1.36 3.21 5.62 (117) 4.90 (99) 84 (102) 4 31 179.1 73.5 22.9 N/A 7.19 1.70 3.57 3.11 (64) 4.05 (88) 74 (89) 5 35 170.2 73.8 25.5 N/A 6.82 1.37 3.03 4.46 (113) 4.52 (114) 82 (101) 6 28 175.3 83.9 27.3 N/A 5.96 1.05 1.05 2.44 2.81 (63) 3.62 (83) 74 (90) 74 (90) Mean Values 32 ± 1 176.6 ± 2.58 76.9 ± 4.33 24.7 ± 1.3 7.02 ± 0.31 1.54 ± 0.14 3.00 ± 0.16 3.73 ± 0.47 (85) 4.23 ± 0.22 (97) 77 ± 1.9 (94) COPD 7 61 168.9 59.4 17.3 Emphysema 6.99 3.33 4.86 0.86 (33) 1.99 (63) 54 (72) 8 70 170.9 92.5 31.7 Emphysema 7.94 2.78 3.98 0.92 (41) 2.92 (100) 57 (77) 9 67 181.1 91.6 27.9 Chronic bronchitis 8.35 2.68 5.41 1.16 (42) 3.31 (94) 58 (78) 10 59 177.0 69.9 22.3 Emphysema 5.58 1.98 3.09 0.61 (21) 1.95 (62) 54 (69) 11 60 168.9 60.8 21.3 Emphysema 6.48 1.96 4.18 0.97 (36) 2.66 (84) 59 (77) 59 (77) 63 * ± 2.2 173.4 ± 2.44 74.8 ± 7.25 24.1 ± 2.5 7.07 ± 0.50 2.55 * ± 0.26 4.30 * ± 0.40 0.90 * ± 0.09 (35) 2.57 * ± 0.26 (81) 56 * ± 1.0 (75) Data are mean ± Standard Error; % of predicted value is given in parentheses; CT, computed tomography; TLC, total lung capacity; RV, Residual Volume; FRC, functional residual capacity, FEF 25-75% , forced expiratory flow at 25 to 75%; FEV 1 ,forced expiratory volume in 1 second; FEV 1 /FVC, ratio of forced expiratory volume in 1 second to forced vital capacity; * p < 0.05 compared to control, N/A: Not Applicable Table 2 Multivariate linear model of airway volumes, alveolar plateau, and tidal volume responses to chest wall strapping conditions Dependent Variable Independent Variable Regression Coefficient (β) Coefficient SE P-Value Adjusted R 2 Anatomical Dead Space (L) Group -0.012 0.002 < 0.001 84.61% Strapped -0.022 0.002 < 0.001 Lung Volume 0.037 0.001 < 0.001 Total Time 0.000 0.000 0.008 Total Time x Strapped 0.000 0.000 0.323 Group x Strapped -0.002 0.001 0.129 Alveolar Dead Space (L) Group 0.032 0.003 < 0.001 61.30% Strapped 0.009 0.003 0.006 Lung Volume 0.014 0.003 < 0.001 Total Time -0.000 0.000 0.418 Total Time x Strapped 0.000 0.000 0.680 Group x Strapped 0.025 0.002 < 0.001 Dead Space to Tidal Volume Ratio (V D /V T ) Group -0.011 0.001 < 0.001 53.98% Strapped -0.001 0.002 0.716 Lung Volume 0.005 0.001 < 0.001 Total Time 0.000 0.000 0.119 Total Time x Strapped -0.000 0.000 0.606 Group x Strapped 0.001 0.001 0.617 Slope (%CO 2 /L) Group 0.098 0.008 < 0.001 63.47% Strapped 0.005 0.009 0.526 Lung Volume -0.133 0.007 < 0.001 Total Time -0.001 0.000 0.017 Total Time x Strapped -0.000 0.000 0.576 Group x Strapped -0.001 0.005 0.812 Normalized Slope Group 0.042 0.003 < 0.001 54.10% Strapped 0.005 0.003 0.122 Lung Volume -0.034 0.002 < 0.001 Total Time -0.000 0.000 0.061 Total Time x Strapped -0.000 0.000 0.759 Group x Strapped -0.001 0.002 0.557 V T (L) Group 0.190 0.013 < 0.001 81.8% Strapped -0.040 0.014 0.005 Lung Volume 0.234 0.017 < 0.001 Total Time -0.000 0.000 0.479 Total Time x Strapped 0.001 0.000 0.074 Group x Strapped 0.132 0.009 < 0.001 Table 3 Multivariate linear model of heart rate, carbon dioxide, and sigh flow in response to chest wall strapping conditions Dependent Variable Independent Variable Regression Coefficient (β) Coefficient SE P-Value Adjusted R 2 Heart Rate (bpm) Group -10.40 1.020 < 0.001 47.57% Strapped -3.350 1.020 0.001 Lung Volume 0.367 0.942 0.697 Total Time -0.069 0.028 0.016 Total Time x Strapped 0.044 0.028 0.121 Group x Strapped 2.380 0.596 < 0.001 Mixed Expired CO 2 (%) Group 0.236 0.014 < 0.001 70.48% Strapped -0.034 0.016 0.028 Lung Volume -0.117 0.013 < 0.001 Total Time -0.001 0.000 0.017 Total Time x Strapped -0.000 0.000 0.413 Group x Strapped -0.057 0.010 < 0.001 End Tidal CO 2 (ETCO 2 ) Type -0.378 0.014 < 0.001 78.01% Strapped -0.043 0.016 0.009 Lung Volume -0.112 0.013 < 0.001 Total Time -0.001 0.000 0.126 Total Time x Strapped -0.001 0.000 0.159 Group x Strapped -0.061 0.010 < 0.001 VCO 2 (L/Breath) Group 0.002 0.001 < 0.001 61.05% Strapped -0.002 0.001 < 0.001 Lung Volume 0.007 0.001 < 0.001 Total Time -0.000 0.000 0.084 Total Time x Strapped 0.000 0.000 0.335 Group x Strapped 0.004 0.000 < 0.001 Sigh Volume Group -0.525 0.030 < 0.001 67.95% Strapped -0.057 0.036 0.090 Lung Volume 0.273 0.030 < 0.001 Total Time 0.001 0.001 0.216 Total Time x Strapped -0.001 0.001 0.399 Group x Strapped -0.051 0.019 0.009 Sigh Peak Flow (L/s) Group -6.130 0.024 < 0.001 99.80% Strapped -0.068 0.022 0.002 Lung Volume 0.041 0.092 0.038 Total Time -0.000 0.001 0.625 Total Time x Strapped 0.001 0.001 0.270 Group x Strapped 0.019 0.013 0.139 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8492362","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":569505321,"identity":"b746dcf2-d578-496a-9e55-55ecd7c539eb","order_by":0,"name":"Michael Eberlein","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIie2PsQrCQAyG41KXQNcriG8gxKVFkPoqJwdORTp2PBB00Xdxcm4RdKnOtykUnFxcRKGgh4iLxdPN4T5Ihp98JAGwWP4S1BXrXh+lwB8J/0Yh3XHFf1MAWETPxKC0JrOsSKjbCCA6s30Zglt/udX4+Va0cxpgR24WrD8W4E2PBkVFvidpiZTNFqovUyBl2rI7BldJN9TWQfEyhZ5RUejXJKVIK3QUd/QWZvxlKPRhAil3gov+BVl+iD8r6012kknYo11RtC9l2HQnYv5ReQN/G7dYLBZLJXe8okhALW/+lwAAAABJRU5ErkJggg==","orcid":"","institution":"University of Wisconsin-Madison","correspondingAuthor":true,"prefix":"","firstName":"Michael","middleName":"","lastName":"Eberlein","suffix":""},{"id":569505326,"identity":"6a77139f-2ec1-472c-a8c8-83fd3dbcd680","order_by":1,"name":"Iliya Amaza","email":"","orcid":"","institution":"University of Wisconsin-Madison","correspondingAuthor":false,"prefix":"","firstName":"Iliya","middleName":"","lastName":"Amaza","suffix":""},{"id":569505327,"identity":"f0fc624c-d944-41d8-9c1c-1c15789e8267","order_by":2,"name":"Eric Abston","email":"","orcid":"","institution":"Massachusetts General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Eric","middleName":"","lastName":"Abston","suffix":""},{"id":569505334,"identity":"7d836fae-97f4-43ba-99f8-8bde0c537212","order_by":3,"name":"Hassan Sajaad","email":"","orcid":"","institution":"Division of Pulmonary and Critical Care Medicine, Atlantic Health System","correspondingAuthor":false,"prefix":"","firstName":"Hassan","middleName":"","lastName":"Sajaad","suffix":""},{"id":569505341,"identity":"c46ddd00-5f0b-4c1c-87f7-3834716977c7","order_by":4,"name":"Melissa. L. Bates","email":"","orcid":"","institution":"University of Iowa, LSF Medical Solutions","correspondingAuthor":false,"prefix":"","firstName":"Melissa.","middleName":"L.","lastName":"Bates","suffix":""}],"badges":[],"createdAt":"2025-12-31 22:08:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8492362/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8492362/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":100006752,"identity":"a392839f-fa64-4079-920f-137905ffad46","added_by":"auto","created_at":"2026-01-12 05:41:38","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":50894,"visible":true,"origin":"","legend":"","description":"","filename":"MauscriptCWSCapnoinitialsubmit.docx","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/e02b5a1fc15b3123d796b25d.docx"},{"id":100006738,"identity":"3b6492e3-5325-4078-b4f5-ee2ff78e1cdf","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":31381,"visible":true,"origin":"","legend":"","description":"","filename":"Tablesinitialsubmission.docx","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/9e93a1aa1e7362fcd25c67eb.docx"},{"id":100006741,"identity":"2c0f318e-6a69-46de-9a91-eb2e1f5366a1","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"json","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7504,"visible":true,"origin":"","legend":"","description":"","filename":"a8f51df3466247d7896f4a036c4beba5.json","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/58b0f481fed608c7c655b89d.json"},{"id":100006739,"identity":"d578c863-2bfd-4dee-bcdc-dfbca27aae2a","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"xml","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":123767,"visible":true,"origin":"","legend":"","description":"","filename":"a8f51df3466247d7896f4a036c4beba51enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/3eeb901cc432a3017038677f.xml"},{"id":100361754,"identity":"b0853ad7-712d-48f3-bc24-b3275902ead7","added_by":"auto","created_at":"2026-01-16 07:45:41","extension":"pdf","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":103766,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1pdf.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/5cdd037b1f360c8c9136d010.pdf"},{"id":100006748,"identity":"2846e2c7-c107-4af9-b616-03cf5df38cfe","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"pdf","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":117648,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/76180aef6f8b39347e5eb931.pdf"},{"id":100006753,"identity":"b76ed5a1-7b1b-455d-9721-e33f1f54bf96","added_by":"auto","created_at":"2026-01-12 05:41:40","extension":"pdf","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":56628,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/d336577e373f88aea08d25eb.pdf"},{"id":100006742,"identity":"c8916b5a-f9a1-4f6e-b62b-46358ae2aebe","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"jpeg","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":660646,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/20a6880cd9bd2e779ff1dc3d.jpeg"},{"id":100006743,"identity":"6f795479-d20e-481f-8d93-b606ec76fff8","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"jpeg","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1074,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/7c25d185c90fb3819c5e7b4e.jpeg"},{"id":100006749,"identity":"7a277016-aded-4deb-8969-f6a3d7e030c8","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":127443,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/d3fb25661258171d2de837e9.png"},{"id":100006745,"identity":"2c865899-0c43-4075-9ee5-5ea0be139382","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":935,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/ca448787b248b11926fd8fca.png"},{"id":100006740,"identity":"9c20e91d-02ee-4754-bbab-ce54922e52e7","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"xml","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":121277,"visible":true,"origin":"","legend":"","description":"","filename":"a8f51df3466247d7896f4a036c4beba51structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/29eb27b55e11a8c29019bf19.xml"},{"id":100006750,"identity":"e5fe9373-025a-4e55-976a-a31531dcaf4a","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"html","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":131832,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/224ca47439b24a6177642647.html"},{"id":100006736,"identity":"046ea9f3-987c-4f55-b472-67c73ccb848b","added_by":"auto","created_at":"2026-01-12 05:41:35","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":56612,"visible":true,"origin":"","legend":"\u003cp\u003eBaseline Capnography: Lines of best fit drawn for each experimental group; VD/VT, total dead space/tidal volume.\u003c/p\u003e","description":"","filename":"Figure1pdf.png","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/cdf24babd09badf3daa0fff0.png"},{"id":100361747,"identity":"b330d69b-9bb4-4a26-b077-9010a1d8f28d","added_by":"auto","created_at":"2026-01-16 07:45:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":51896,"visible":true,"origin":"","legend":"\u003cp\u003eExperimental capnography over time: the dotted lines indicate transitions from the unstrapped condition measured at baseline to the strapped condition and from the strapped condition to the post strapped condition respectively; Tick marks indicate stand error; VD/VT, anatomic dead space/tidal volume.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/a4e01969cfeb7ff4ed088b25.png"},{"id":100006744,"identity":"3ac8b25d-df16-4f17-bbdf-9d7281213759","added_by":"auto","created_at":"2026-01-12 05:41:36","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":54054,"visible":true,"origin":"","legend":"\u003cp\u003eAdditional experimental measures over time: the dotted lines indicate transitions from the unstrapped condition measured from baseline to the strapped condition and from the strapped condition to the post-strapped condition respectively; Tick marks indicate stand\u003c/p\u003e\n\u003cp\u003eerror; ETCO2, end tidal CO2.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/ef7f55c6562723de9791ce8e.png"},{"id":105884396,"identity":"5c6ca2ac-6dde-489a-9545-e744920e8d7e","added_by":"auto","created_at":"2026-04-01 07:13:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1318544,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8492362/v1/a1bad0ce-35ce-4674-9cb0-26a368b9460f.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Research Article, Title: Chest Wall Strapping dilates airways and increases airway homogeneity in COPD","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eChronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality globally [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. COPD is characterized by progressive airway obstruction associated with the lung\u0026rsquo;s inflammatory response to noxious particles or agents, like cigarette smoke and has two major components: emphysema and chronic bronchitis [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Together, airway narrowing and loss of airway traction caused by alveolar destruction contribute to airway collapse and air trapping that is associated with decreased exercise tolerance and diminished quality of life [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Airway dysfunction and air trapping are present even in patients with relatively mild disease and progress over time [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Airways\u0026thinsp;\u0026le;\u0026thinsp;2 mm are particularly vulnerable to collapse in these patients [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eChest wall strapping (CWS) is a historical physiological technique that has recently been shown to have possible relevance to the diagnosis and treatment of lung disease [\u003cspan additionalcitationids=\"CR8 CR9 CR10\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. CWS restricts the chest wall to induce breathing at low lung volumes [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. CWS increases lung elastic recoil and expiratory airflows [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Our group previously evaluated the lung structure function relationship in COPD before and after CWS, using pulmonary function studies and computed tomography [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. CWS induced a 316% improvement in expiratory airflow and a 79% increase in the number of detectable airways small airways\u0026thinsp;\u0026le;\u0026thinsp;2 mm in subjects with COPD [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Dynamic-dysanapsis describes the concept of airway dilation via interdependence of airways and lung parenchyma from CWS induced increase in lung elastance [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This suggests that CWS may be clinically useful in improving small airway function and possibly recruiting collapsed airways.\u003c/p\u003e \u003cp\u003eHowever, there are several unanswered questions that are important in understanding the possible therapeutic utility of CWS. Specifically, little is known about the time course of airway recruitment during CWS and it is not known whether there is any persistent benefit to airways recruitment after removal of the chest wall strap. While essential in establishing the initial physiology of small airways recruitment by CWS in COPD, computed tomography requires radiation exposure and multiple repeated scans to establish a time course are not feasible. Typical computed tomography studies of the lung deliver 0.15 mSv of radiation energy, but even very low radiation doses (0.1\u0026ndash;150 mSv) are associated with an increased lifetime risk of cancer [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVolumetric capnography is a single breath gas washout technique that utilizes the profile of exhaled CO\u003csub\u003e2\u003c/sub\u003e to derive information about the airway and alveolar dead spaces and heterogeneity of the distal airways. Experimentally, volumetric capnography is similar to clinical capnography, with the added requirement that measurements be made at controlled flow rates and lung volumes so that they can be compared between conditions and over time [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Members of our group have used volumetric capnography previously to evaluate airways volume and heterogeneity at functional residual capacity after air pollution exposure [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The airways are tractioned by the parychema and airway diameter is highly dependent on lung volume [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Coupling volumetric capnography with plethysmography allows for capnographic estimates of dead space volume and heterogeneity to be made at multiple lung volumes and the full lung structure-function relationship to be derived. We have published detailed methodology on the combined use of these techniques [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe purpose of this study was to quantify the lung structure-function relationship in COPD before, during, and after CWS. We hypothesized that CWS would induce an immediate improvement in airway volume and heterogeneity that would cease upon removal of CWS. This method allows for the comprehensive interrogation of the effects of CWS over extended time periods and lung volumes. We specifically investigated the changes in airway volume (i.e., dead space) attributed to application and removal of strapping. An increase in dead space is attributed to an increase in airway dimensions and airway recruitment. A decrease in dead space would indicate a decrease in airway dimensions. We hypothesized that CWS will cause an increase in dead space of COPD patients because of a CWS induced increase in airway dimensions. Secondly, we measured effects of CWS on airway uniformity, and we hypothesized that CWS increases airway homogeneity.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003e \u003cb\u003eStudy cohort and overall design\u003c/b\u003e. Male participants with COPD were recruited from the University of Iowa COPD-Gene cohort (n\u0026thinsp;=\u0026thinsp;5) and healthy, sex-matched controls (n\u0026thinsp;=\u0026thinsp;5) were recruited from the general population at the University of Iowa. COPD subjects participated in the previous CWS lung imaging study [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Inclusion criteria for participants with COPD included a documented clinical history of COPD, FEV\u003csub\u003e1\u003c/sub\u003e/FVC\u0026thinsp;\u0026lt;\u0026thinsp;0.70 on the day of study, and willingness to tolerate the CWS device. Control participants reported no clinical history of lung or cardiovascular disease, had a normal FEV\u003csub\u003e1\u003c/sub\u003e/FVC on the day of study, and were also willing to tolerate the CWS device. All experiments were performed in accordance with the Declaration of Helsinki and participants provided informed consent prior to participation. This study was approved by the Institutional Review Board of the University of Iowa.\u003c/p\u003e \u003cp\u003eParticipants visited the laboratory on a single occasion, and the experimental design was the same for both groups. Anthropometric data, including height, weight, age, COPD medical history, and ethnicity were collected. Lung volumes and pulmonary function were assessed using standard clinical plethysmography and spirometry. Prior to CWS, participants sat at a custom station for the measurement of baseline ventilation and volumetric capnography. A piezo-electric transducer was placed around the index finger to record heart rate (TN1012/ST, AD Instruments, Colorado Springs, CO). One minute of stable, baseline ventilation data was collected. They were then coached to perform the volumetric capnography maneuver. After performing these baseline measurements, participants were fitted with the chest wall strap used previously [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Briefly, each individual was coached to empty their lungs to residual volume while the strap was tightened around the chest. Baseline ventilation, plethysmograpy, and capnography was repeated every 15 minutes for one hour following application of the strap. The strap was then removed, baseline ventilation was assessed, and volumetric capnography measurements were repeated every 15 minutes for an additional hour. It is hypothesized that CWS mechanistically increases elastic recoil by the altering the air-fluid interface of the lung and that inhalation to total lung capacity interferes with these effects [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Because spirometry and plethysmography require deep inhalation that might interfere with our ability to measure the time course of CWS-induced changes in airways function, plethysmography was not performed again after removal of the chest wall strap. After an hour of measurements post-CWS capnography measurements, participants were coached to take a total lung capacity breath and capnography was repeated.\u003c/p\u003e \u003cp\u003e \u003cb\u003eChest Wall Strapping Procedure.\u003c/b\u003e A commercially available flotation vest (Stearns adult life vest) was placed around the chest and upper abdomen. Participants were coached to exhale to residual volume and the vest was tighten to reduce the total lung capacity to ~\u0026thinsp;70% of baseline [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e\u003cb\u003eSpirometry and plethysmography.\u003c/b\u003e Spirometry and plethysmography was performed using commercially available equipment (V62J, Vyaire Medical, Mettawa, IL) in the University of Iowa Institute for Clinical Research in accordance with current consensus statements [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], as we have described previously [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. At least three plethysmographic maneuvers were completed until two values of functional residual capacity (FRC) within 5% were obtained. Where appropriate, expiratory flow rates and lung volumes were compared to the NHANES and Goldman and Becklake predictive equations [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e\u003cb\u003eVentilation and volumetric capnography.\u003c/b\u003e For measures of baseline ventilation, participants donned noseclips and were coached to sit upright, place their feet on the floor, insert the mouthpiece, and breathe quietly. The real time profiles of exhaled tidal volumes and carbon dioxide were observed by an investigator and one minute of data was collected when tidal volume and end tidal carbon dioxide were deemed to be stable. Expiratory flow rates and carbon dioxide concentration were measured using commercially available equipment as described previously [\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], including a heated pneumotach set to 37\u0026deg;C and a rapidly responding gas analyzer.\u003c/p\u003e \u003cp\u003eThe same equipment was used for volumetric capnography measurements and the principles and application of our technique have been described previously [\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Step-by-step instructions to reproduce the technique, calibration information, and the analysis macro have been published and are freely available [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Briefly, participants were coached to follow a pattern displayed on a computer screen to generate two pairs of two-breath maneuvers at targeted inhalation and exhalation flow rates (250 mL/s) and durations (3s for the first breath and 5s for the second breath, see example as described in detail at [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]). Measurements were made at different initial lung volumes by coaching participants to vary the volume of the lung immediately before the initiation of the maneuver. At the end of the maneuver, participants were coached to sigh with an open glottis and lung volume where the expiratory flow reached zero was set as FRC. Initial lung volumes were referenced to this point. Based on previous inter-maneuver variability studies [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], a total of 8 maneuvers were collected at each time point\u003c/p\u003e \u003cp\u003e \u003cb\u003eData Analysis\u003c/b\u003e. Data were acquired in LabChart (AD Instruments, Colorado Springs, CO). Carbon dioxide and flow data were processed in an excel-based macro to generate volumetric capnograms from which anatomic dead space and the slope of the alveolar plateau were determined. and plethysmograph data, we extrapolated using an excel MACRO program the following values: anatomic dead space, alveolar dead space, VD/VT, and slope (CO\u003csub\u003e2\u003c/sub\u003e/L). We also measured lung volume, heart rate, ETCO\u003csub\u003e2\u003c/sub\u003e, and peak sigh flow. All graphing was done in the 2019 edition of GraphPad Prism. Repeated measure analysis of covariance (ANCOVA) tests were run on Minitab 18 to find differences between the experimental groups, volumes measured, CWS and post-CWS conditions, and relationships between these categories. The ANCOVA test was chosen as lung volume is a continuous measure. A more in-depth integration and analysis of both capnography and plethysmography data is described in detail in our previous publication [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Statistical significance was set at \u003cem\u003ea priori\u003c/em\u003e p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eAnthropometric data for the Control and COPD group are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. COPD subjects were older than controls (63\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2 years vs. 32\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 years, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There was no difference in height, weight, or BMI. The CT-scans revealed emphysema as the primary phenotype for 4 of 5 COPD subjects. The remaining subject\u0026rsquo;s primary COPD-phenotype was chronic bronchitis. As expected, baseline plethysmography and spirometry were different, consistent with the COPD group\u0026rsquo;s diagnosis (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Residual volume (RV) and functional residual capacity (FRC) were higher in the COPD group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003ch3\u003eBaseline Capnography\u003c/h3\u003e\n\u003cp\u003eBecause of the well-established relationships between airway resistance and lung volume we related capnographic parameters to lung volume. As predicted airway volume was related to lung volume in both groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). There was a difference in anatomic dead space between the two groups, with COPD subjects on average having lower anatomic deadspace (p\u0026thinsp;=\u0026thinsp;0.039). Alveolar dead space was correlated with lung volume (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and there was a group by volume interaction (p\u0026thinsp;=\u0026thinsp;0.024, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). The slope of the capnogram (CO2/L) in relationship to lung volume showed more airway heterogeneity and in COPD subjects compared to normal subjects at any lung volume (p\u0026thinsp;=\u0026thinsp;0.003, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD). The slope of the capnogram (CO2/L) differed between the control and COPD groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with a correlation between slope and lung volume (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), as well as a group by volume interaction (p\u0026thinsp;=\u0026thinsp;0.003).\u003c/p\u003e\n\u003ch3\u003eExperimental CWS Capnography\u003c/h3\u003e\n\u003cp\u003eTo track the change in the relationship between airway resistance and lung volume we related anatomic dead space, alveolar dead space, V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e, and slope of the capnogram (CO2/L) to lung volume and tracked their change over time. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC, p\u0026thinsp;=\u0026thinsp;0.006). Overall, the control subjects had smaller anatomic dead spaces over the course of the experiment (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA). Moving from unstrapped to the CWS and to post-CWS condition, we saw an overall increase in the anatomic dead space for both groups with CWS and post-CWS. (p\u0026thinsp;=\u0026thinsp;0.001). The absence of a group by strapped relationship indicated that both groups respond similarly to strapping. There was a difference in alveolar dead space between the two groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB). The group by strapped effect (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) indicated that the transition from the CWS condition to post-CWS condition had markedly different impacts on the alveolar dead space. The COPD group showed an immediate increase in the alveolar dead space. The control group showed an opposite effect with a small decrease in the alveolar dead space. Over the course of the experiment, the relationship of total dead space to tidal volume (V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e) remained larger in the control group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC). Strapping did not have an effect on V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e for either experimental group. Additionally, because of the lack of a group by strapped relationship, both control and COPD groups V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e reacted to CWS and post-CWS in the same way. The capnographic slope is an indicator of airway uniformity. The slope versus time can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD. The percent CO\u003csub\u003e2\u003c/sub\u003e to absolute lung volume differs between the groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Due to the lack of a group by strapped relationship, both groups reacted to CWS and post-CWS in the same way. Post-CWS had a large effect on both groups causing a decrease in the slope to lung volume ratio (p\u0026thinsp;=\u0026thinsp;0.0303).\u003c/p\u003e\n\u003ch3\u003eAdditional Experimental Measures\u003c/h3\u003e\n\u003cp\u003eTo better understand the physiological changes occurring with CWS, we tracked several other measurements over the course of the experiment. The control group showed much higher heart rates throughout the testing (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). There was an elevated response in heart rate for the CWS condition compared to the post-CWS condition, (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The control group exhibited higher end-tidal CO\u003csub\u003e2\u003c/sub\u003e measures for the entire experiment (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB). We saw a differing correlation between the COPD and control groups and the CWS and post-CWS condition for end-tidal CO\u003csub\u003e2\u003c/sub\u003e (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). However, we saw no overall difference between the CWS and post-CWS conditions. Peak sigh flow measurements were different between control and COPD groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC) and different between overall CWS and post-CWS conditions (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The was no overall correlation between the groups and strapped conditions, meaning the two groups responded similarly to strapping. They showed a slight increase in peak sigh flow with the addition of strapping, and persistence in that increase for the remainder of the experiment. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD shows that COPD patients breath at much higher lung volumes than control patients over the entire experiment, with an increase in Post-CWS conditions (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn this study we examined the time course of CWS on the lung structure function relationship in COPD and control subjects. When analyzed in the context of absolute lung volume, CWS increased anatomic dead space and airway uniformity in COPD and normal controls. The increased anatomic deadspace is likely from an increase in small airway dimensions. Dynamic-dysanapsis describes airway dilation via airway-lung interactions mediated by increased elastic recoil induced by CWS. In addition to increased airway dimensions, CWS was associated with improved airway homogeneity. These observations and especially the persistence of the CWS effect after the intervention suggest the potential of using CWS as a novel therapeutic intervention for COPD patients to improve the lung structure function relationship.\u003c/p\u003e \u003cp\u003eVolumetric capnography can evaluate the impact of CWS on dead space. For both COPD and control patients we saw an increase in anatomic dead space due to strapping. Post-strap removal we saw this increase in anatomic dead space remained. This is consistent with our hypothesis that predicted an increase in dead space due to the larger number of small airways being held open in response to strapping. When looking at alveolar dead space in the control group, we again saw a small increase in dead space with CWS and a small decrease in the post-CWS condition. However, in the COPD group we saw an increase in the alveolar dead space with the removal of the strap. This indicated that in COPD patients, the effect of strapping persists after the straps have been removed. Likely more small airway remain dilated, with more alveoli available for gas exchange.\u003c/p\u003e \u003cp\u003eWe see the effect of airway dilation in the peak sigh flow measures over time for the COPD patients. There is a persistent increase in flow after CWS that was maintained after the strapping was removed. This indicated CWS allows COPD patients to move air out of their lungs more easily, likely due to the dilation of the small airways. The control patients show little change in the peak sigh flow over time. We suspect this is because it is necessary for COPD patients to breath at larger lung volumes as they have larger functional residual capacity\u0026rsquo;s (FRC). Thus, if they are breathing at larger lung volumes and get restricted, there will be a greater impact on peak sigh flow than the controls who have lower FRC\u0026rsquo;s.\u003c/p\u003e \u003cp\u003eThe ratio of total dead space to tidal volume (V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e) is higher in the control vs COPD individuals. This difference can be accounted for considering that V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e the includes the total dead space of the individual, that means the sum of both anatomic dead space and alveolar dead space. When adding the anatomic and alveolar dead spaces for the control group we found an increase in both anatomic dead space and alveolar dead space with CWS. Thus, they added to an overall increase. Furthermore, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD shows that control individuals breath at much lower lung volumes than the COPD patients. So, when the two larger values are divided by smaller volume, we see a larger ratio for the control overall. The lower V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e ratio the COPD patients can also be accounted for by the addition of the two dead spaces to get total dead space. We see an increase in anatomic dead space with strapping opposed by the increase in alveolar dead space with strapping. This balances out to a lower average value for the CWS condition. This average value is divided by larger average lung volumes for COPD patients (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD). Thus, the ratio is smaller overall for COPD patients throughout the experiment.\u003c/p\u003e \u003cp\u003eGreen originally described dysanapsis as an anatomic mismatch between airway size and lung volume that arose because of developmental heterogeneity [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Dynamic-Dysanapsis describes changes in the lung structure function relationship: Increased lung elastance with CWS dilates airways via interdependence [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. We have previously shown dynamic-dysapasis with CWS in a porcine model [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Dynamic-dysanapsis appears to be a compensatory mechanism to preserve pulmonary gas exchange efficiency by airway dilation when the lung operates at lower volumes. Transplanting an oversized lung allograft into a smaller recipients chest has similarities to CWS [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. We reported supranormal expiratory airflows associated with oversized lung allografts [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Oversized allografts had higher FEV\u003csub\u003e1\u003c/sub\u003e/FVC ratios (0.895\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13 vs 0.821\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01) and a lower risk of bronchiolitis obliterans syndrome (BOS) than undersized allografts [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. BOS is characterized by progressive scarring and narrowing of the small airways (bronchioles) and is the major cause of death after lung transplantation. We have demonstrated that oversized allografts are associated with improved survival following lung transplantation [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Dynamic-dysanapsis via CWS was demonstrable in a CT imaging study of COPD subjects. CWS increased the mean number of detectable airways with a diameter of \u0026le;\u0026thinsp;2 mm by 79% (59\u0026thinsp;\u0026plusmn;\u0026thinsp;19 vs. 104\u0026thinsp;\u0026plusmn;\u0026thinsp;16, P\u0026thinsp;=\u0026thinsp;0.01) in subjects with COPD [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe slope of the capnogram evaluates the heterogeneity of the airway. With an increased slope corresponding to a larger difference in the airway uniformity. For both control and COPD patients we saw a decrease in slope due to strapping and a further decrease with the removal of strapping. Thus, we see chest wall strapping improves the homogeneity of the airways with persistent effects into post-CWS condition. These results indicate that CWS could help alleviate air trapping that occurs in COPD patients and dynamic hyperinflation, as their airways become more homogenous.\u003c/p\u003e \u003cp\u003eOur additional experimental measures can be used to evaluate the safety of CWS as an intervention for COPD individuals. A concern when restricting the chest wall is the potential for the increased work of breathing it may cause. Increased work of breathing could limit ventilation, leading to an increased ETCO\u003csub\u003e2\u003c/sub\u003e. Our data (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB) for both the COPD and control groups show maintenance of ETCO\u003csub\u003e2\u003c/sub\u003e compared to baseline with the addition of CWS. Furthermore, we see a decrease once the CWS is removed. So, we can conclude that CWS does not cause a clinically significant increase in work of breathing in subjects with GOLD stage I-III COPD.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eLimitations of our study could include the small sample size, subjects were male and mostly emphysema-predominant GOLD I\u0026ndash;III. A more widespread study across the phenotypes of COPD to confirm our results would be beneficial in further defining how CWS effects the lung structure function relationship. We demonstrated dynamic-dysnapsis, increased lung elastance with CWS dilates airways via interdependence, in a porcine model and in larger cohort studies of recipients of oversized lung allografts [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. This suggests that dynamic-dysnapsis could be a canonical mechanism to preserve pulmonary gas exchange efficiency by airway dilation when the lung operates at lower volumes.\u003c/p\u003e \u003cp\u003eAnother limitation is the nature of the tests themselves. Pulmonary function tests can be variable within an individual and a longitudinal study over several months would be beneficial to see if the effects of CWS continue to be apparent with multiple applications of the device. Increasing anatomical dead space was interpreted as airway dilation/recruitment. While we cannot rule out alternative explanations such as shifts in operating lung volumes, or differences in mouthpiece dead space handling the same subjects had CT imaging evidence of airway dilation in a previous study [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eIn confirmation of previous imaging studies [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] we have shown that CWS does dilate airways quantified by the increase in dead space seen for COPD patients. Furthermore, the increase in airway homogeneity persists at least 45 minutes after strapping is removed. This indicates lasting benefits of CWS on the lung structure function relationship in COPD. Overall, we conclude that CWS should be further investigated as a potential nonpharmacological intervention in COPD patients to improve small airway function. In future studies we plan to test if the post CWS effect can increase effectiveness of inhaled medications such as albuterol. The dilatation of airways and the improvement in airway homogeneity during and after CWS could help for inhaled therapies to be delivered more effectively.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCWS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eChest wall strapping\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCOPD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eChronic obstructive pulmonary disease\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComputer Tomography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFEV\u003csub\u003e1\u003c/sub\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eforced expiratory volume in 1 second\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFRC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003efunctional residual capacity\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFVC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eforced vital capacity\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePFT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003epulmonary function studies\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eAll experiments were performed in accordance with the Declaration of Helsinki and participants provided informed consent prior to participation. This study was approved by the Institutional Review Board of the University of Iowa.\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eDe-identified data and analysis code are available from the corresponding author upon reasonable request and subject to institutional policies.\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe authors have no conflicts to declare. Dr. Bates is Founder and CEO of LSF Medical Solutions whose work overlaps topically with the content of the manuscript. She received no reimbursement for her participation in this project.\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThis work was supported by a PILOT grant from the Institute for Clinical and Translational Science at the University of Iowa via the National Center for Advancing Translational Sciences Grant UL1-TR-000442 (M. Eberlein).\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eME, IA, HS, and MLB designed the study, ME, HS, IA, and MLB collected data, ME, HS, IA, and MLB analyzed and interpreted the data, ME and MLB drafted the manuscript, ME, HS, IA, EA and MLB edited and approved the final manuscript\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eHarold Winnike, Elizabeth Pritchard, Caylie Sheridan and Erik P. Tomasson participated in aspects of this study and their contributions are appreciated.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eNaeem S, Wang F, Mubarak R, et al. Mapping the Global distribution, risk factors, and temporal trends of COPD incidence and mortality (1990\u0026ndash;2021): ecological analysis. BMC Med. 2025;23:210.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOwusuaa C, Dijkland SA, Nieboer D, et al. Predictors of mortality in chronic obstructive pulmonary disease: a systematic review and meta-analysis. BMC Pulm Med. 2022;22:125. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12890-022-01911-5\u003c/span\u003e\u003cspan address=\"10.1186/s12890-022-01911-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWachami AL, Guennouni N, Iderdar M. Estimating the global prevalence of chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis. BMC Public Health. 2024;24:297. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12889-024-17686-9\u003c/span\u003e\u003cspan address=\"10.1186/s12889-024-17686-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScichilone N, Whittamore A, White C, et al. The patient journey in Chronic Obstructive Pulmonary Disease (COPD): a human factors qualitative international study to understand the needs of people living with COPD. BMC Pulm Med. 2023;23:506. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12890-023-02796-8\u003c/span\u003e\u003cspan address=\"10.1186/s12890-023-02796-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim T, Kim Y, Bak SH, et al. Longitudinal parametric response mapping on CT in assessing functional small airway disease and emphysema in COPD. Sci Rep. 2025;15:37221. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/s41598-025-21015-4\u003c/span\u003e\u003cspan address=\"10.1038/s41598-025-21015-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcDonough JE, Yuan R, Suzuki M, et al. Small-Airway Obstruction and Emphysema in Chronic Obstructive Pulmonary Disease. N Engl J Med. 2011;365:1567\u0026ndash;75. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1056/NEJMoa1106955\u003c/span\u003e\u003cspan address=\"10.1056/NEJMoa1106955\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEberlein M, Schmidt GA, Brower RG. Chest wall strapping. An old physiology experiment with new relevance to small airways diseases. Ann Am Thorac Soc. 2014;11:1258\u0026ndash;66.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStubbs SE, Hyatt RE. Effect of increased lung recoil pressure on maximal expiratory flow in normal subjects. J Appl Physiol. 1972;32:325\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaher H, Bauer C, Abston E, et al. Chest wall strapping increases expiratory airflow and detectable airway segments in computer tomographic scans of normal and obstructed lungs. J Appl Physiol. 2018;124:1186\u0026ndash;93.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbston E, Eberlein M. Chest wall strapping in a porcine model: A model for the physiology of the oversized lung allograft. JHLT Open. 2025;8:100248. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhlto.2025.100248\u003c/span\u003e\u003cspan address=\"10.1016/j.jhlto.2025.100248\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbston E, Eberlein M. Chest wall strapping in a porcine model: Dynamic dysanapsis dilates airways for optimized function of the oversized lung. JHLT Open. 2025;9:100317. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhlto.2025.100317\u003c/span\u003e\u003cspan address=\"10.1016/j.jhlto.2025.100317\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePierce DA, Preston DL. Radiation-related cancer risks at low doses among atomic bomb survivors. Radiat Res. 2000;154:178\u0026ndash;86.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaker LG, Ultman JS, Rhoades RA. Simultaneous gas flow and diffusion in a symmetric airway system: a mathematical model. Respir Physiol. 1974;21:119\u0026ndash;38.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSeymour M, Pritchard E, Sajjad H, Tomasson EP, Blodgett CM, Winnike H, Paun OV, Eberlein M, Bates ML. Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship. J Vis Exp 11, 2019.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaylor AB, Lee GM, Nellore K, Ben-Jebria A, Ultman JS. Changes in the carbon dioxide expirogram in response to ozone exposure. Toxicol Appl Pharmcol. 2006;213:1\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBates ML, Brenza TM, Ben-Jebria A, Bascom R, Eldridge MW, Ultman JS. Pulmonary function responses to ozone in smokers with a limited smoking history. Toxicol Appl Pharmcol. 2014;278:85\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBates ML, Brenza TM, Ben-Jebria A, Bascom R, Ultman JS. Longitudinal distribution of ozone absorption in the lung: comparison of cigarette smokers and nonsmokers. Toxicol Appl Pharmcol. 2009;236:270\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWest JB. Respiratory Physiology: The Essentials 8th Edition. Philadelphia: Wolters Kluwer, 2008, p. 208.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYoung SL, Tierney DF, Clements JA. Mechanism of compliance change in excised rat lungs at low transpulmonary pressure. J Appl Physiol. 1970;29:780\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWanger J, Clausen JL, Coates A, et al. Standardisation of the measurement of lung volumes. Eur Respir J. 2005;26:511\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCulver BH, Graham BL, Coates AL, et al. Recommendations for a Standardized Pulmonary Function Report. An Official American Thoracic Society Technical Statement. Am J Respir Crit Care Med. 2017;196:1463\u0026ndash;72.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGoldman HI, Becklake MR. Respiratory function tests; normal values at median altitudes and the prediction of normal results. Am Rev tuberculosis. 1959;79:457\u0026ndash;67.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGreen M, Mead J, Turner JM. Variability of maximum expiratory flow-volume curves. J Appl Physiol. 1974;37:67\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEberlein M, Permutt S, Brown RH, et al. Supranormal expiratory airflow after bilateral lung transplantation is associated with improved survival. Am J Respir Crit Care Med. 2011;183(1):79\u0026ndash;87. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1164/rccm.201004-0593OC\u003c/span\u003e\u003cspan address=\"10.1164/rccm.201004-0593OC\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEberlein M, Permutt S, Chahla MF, et al. Lung size mismatch in bilateral lung transplantation is associated with allograft function and bronchiolitis obliterans syndrome. Chest. 2012;141(2):451\u0026ndash;60. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1378/chest.11-0767\u003c/span\u003e\u003cspan address=\"10.1378/chest.11-0767\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEberlein M, Reed RM, Maidaa M, et al. Donor-recipient size matching and survival after lung transplantation. A cohort study. Ann Am Thorac Soc. 2013;10(5):418\u0026ndash;25. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1513/AnnalsATS.201301-008OC\u003c/span\u003e\u003cspan address=\"10.1513/AnnalsATS.201301-008OC\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEberlein M, Reed RM, Abston E, et al. Sizing in lung transplantation: principles, practices and ideas for the future. JHLT Open. 2025;9:100304. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jhlto.2025.100304\u003c/span\u003e\u003cspan address=\"10.1016/j.jhlto.2025.100304\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cdiv id=\"Fig1\" class=\"Figure\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable\u0026nbsp;1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAnthropometric characteristics of normal subjects and subjects with mild to moderate COPD (GOLD stages 1-3)\u003c/div\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr style=\"height: 29px;\"\u003e\n\u003cth style=\"height: 29px;\" colspan=\"2\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eSubject\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAge (yr)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eHeight (cm)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eWeight (kg)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eBMI\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003ePrimary CT scan phenotype\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTLC\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eRV\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eFRC\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eFEF \u003csub\u003e25\u0026minus;75%\u003c/sub\u003e\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eFEV\u003csub\u003e1\u003c/sub\u003e\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth style=\"height: 29px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eFEV\u003csub\u003e1\u003c/sub\u003e/FVC\u003c/div\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 91.8796px;\" rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eControl\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e32\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e175.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e58.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e19.2\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e6.49\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.77\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.97\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.63 (60)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.62 (82)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e73 (89)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e33\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e172.0\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e83\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e28.1\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e8.07\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.01\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.82\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.77 (92)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.67 (114)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e77 (95)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e32\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e187.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e88.4\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e25.0\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e7.61\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.36\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.21\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e5.62 (117)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.90 (99)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e84 (102)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e31\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e179.1\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e73.5\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e22.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e7.19\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.70\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.57\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.11 (64)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.05 (88)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e74 (89)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13.8796px;\"\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e5\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e35\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e170.2\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e73.8\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e25.5\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e6.82\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.37\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.03\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.46 (113)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.52 (114)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13.8796px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e82 (101)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 26px;\"\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e6\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e28\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e175.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e83.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e27.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e5.96\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.05\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.05\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.44\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.81 (63)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.62 (83)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e74 (90)\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e74 (90)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 26px;\"\u003e\n\u003ctd style=\"height: 26px;\" colspan=\"2\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eMean Values\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e32\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e176.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.58\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e76.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.33\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e24.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e7.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.73\u0026thinsp;\u0026plusmn;\u0026thinsp;0.47 (85)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 (97)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 (94)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 78px;\" rowspan=\"5\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eCOPD\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e7\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e61\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e168.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e59.4\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e17.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eEmphysema\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e6.99\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.33\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.86\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.86 (33)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.99 (63)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e54 (72)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e8\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e70\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e170.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e92.5\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e31.7\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eEmphysema\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e7.94\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.78\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.98\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.92 (41)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.92 (100)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e57 (77)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e67\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e181.1\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e91.6\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e27.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eChronic bronchitis\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e8.35\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.68\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e5.41\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.16 (42)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.31 (94)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e58 (78)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 13px;\"\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e10\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e59\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e177.0\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e69.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e22.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eEmphysema\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e5.58\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.98\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3.09\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.61 (21)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.95 (62)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 13px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e54 (69)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 26px;\"\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e11\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e60\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e168.9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e60.8\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e21.3\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eEmphysema\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e6.48\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.96\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.18\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.97 (36)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.66 (84)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 26px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e59 (77)\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e59 (77)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr style=\"height: 28px;\"\u003e\n\u003ctd style=\"height: 28px;\" colspan=\"2\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e63\u003csup\u003e*\u003c/sup\u003e \u0026plusmn; 2.2\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e173.4 \u0026plusmn; 2.44\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e74.8 \u0026plusmn; 7.25\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e24.1\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u0026plusmn;\u0026thinsp;2.5\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e7.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.55\u003csup\u003e*\u003c/sup\u003e \u0026plusmn; 0.26\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e4.30\u003csup\u003e*\u003c/sup\u003e \u0026plusmn; 0.40\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.90\u003csup\u003e*\u003c/sup\u003e \u0026plusmn; 0.09 (35)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.57\u003csup\u003e*\u003c/sup\u003e \u0026plusmn; 0.26 (81)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd style=\"height: 28px;\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e56\u003csup\u003e*\u003c/sup\u003e \u0026plusmn; 1.0 (75)\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eData are mean \u0026plusmn; Standard Error; % of predicted value is given in parentheses; CT, computed tomography; TLC, total lung capacity; RV, Residual Volume; FRC, functional residual capacity, FEF \u003csub\u003e25-75%\u003c/sub\u003e, forced expiratory flow at 25 to 75%; FEV\u003csub\u003e1\u003c/sub\u003e,forced expiratory volume in 1 second; FEV\u003csub\u003e1\u003c/sub\u003e/FVC, ratio of forced expiratory volume in 1 second to forced vital capacity; * p \u0026lt; 0.05 compared to control, N/A: Not Applicable\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable\u0026nbsp;2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eMultivariate linear model of airway volumes, alveolar plateau, and tidal volume responses to chest wall strapping conditions\u003c/div\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eDependent Variable\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eIndependent Variable\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eRegression Coefficient (\u0026beta;)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eCoefficient SE\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eP-Value\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAdjusted R\u003csup\u003e2\u003c/sup\u003e\u003c/div\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAnatomical Dead Space (L)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.012\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e84.61%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.022\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.037\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.008\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.323\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.129\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAlveolar Dead Space\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.032\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.003\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e61.30%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.009\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.003\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.006\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.014\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.003\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.418\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.680\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.025\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eDead Space to Tidal Volume Ratio\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.011\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e53.98%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.716\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.005\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.119\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.606\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.617\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eSlope\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(%CO\u003csub\u003e2\u003c/sub\u003e/L)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.098\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.008\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e63.47%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.005\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.009\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.526\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.133\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.007\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.017\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.576\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.005\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.812\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eNormalized Slope\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.042\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.003\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e54.10%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.005\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.003\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.122\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.034\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.061\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.759\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.557\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eV\u003csub\u003eT\u003c/sub\u003e\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.190\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.013\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e81.8%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.040\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.014\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.005\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.234\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.017\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.479\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.074\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.132\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.009\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable\u0026nbsp;3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eMultivariate linear model of heart rate, carbon dioxide, and sigh flow in response to chest wall strapping conditions\u003c/div\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eDependent Variable\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eIndependent Variable\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eRegression Coefficient (\u0026beta;)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eCoefficient SE\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eP-Value\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAdjusted R\u003csup\u003e2\u003c/sup\u003e\u003c/div\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eHeart Rate\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(bpm)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-10.40\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.020\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e47.57%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-3.350\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e1.020\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.367\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.942\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.697\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.069\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.028\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.016\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.044\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.028\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.121\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2.380\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.596\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eMixed Expired CO\u003csub\u003e2\u003c/sub\u003e (%)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.236\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.014\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e70.48%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.034\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.016\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.028\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.117\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.013\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.017\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.413\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.057\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.010\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eEnd Tidal CO\u003csub\u003e2\u003c/sub\u003e\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(ETCO\u003csub\u003e2\u003c/sub\u003e)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eType\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.378\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.014\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e78.01%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.043\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.016\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.009\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.112\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.013\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.126\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.159\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.061\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.010\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eVCO\u003csub\u003e2\u003c/sub\u003e (L/Breath)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e61.05%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.002\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.007\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.084\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.335\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.004\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eSigh Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.525\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.030\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e67.95%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.057\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.036\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.090\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.273\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.030\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.216\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.399\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.051\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.019\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.009\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eSigh Peak Flow\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003e(L/s)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-6.130\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.024\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e99.80%\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eStrapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.068\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.022\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.002\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eLung Volume\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.041\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.092\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e0.038\u003c/span\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e-0.000\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.625\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eTotal Time x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.270\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup x Strapped\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.019\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.013\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0.139\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Chest Wall Strapping, Airway parenchymal interdependence, Dysanapsis, COPD","lastPublishedDoi":"10.21203/rs.3.rs-8492362/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8492362/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eChest wall strapping (CWS) is a technique that restricts the chest wall to induce breathing at lower lung volumes. CWS increases lung elastic recoil and expiratory airflows. In computer tomography imaging studies CWS dilates small airways in healthy and COPD-subjects. Dynamic-dysanapsis describes the concept of airway dilation via interdependence of airways and lung parenchyma from CWS induced increase in lung elastance. The time course of CWS induced dynamic-dysnapsis is not defined. Volumetric capnography and plethysmography allow for repeated measurements of the lung structure function relationship. We hypothesized that CWS causes an increase in dead space of COPD-subjects via CWS induced increase in airway dimensions. Secondly, we hypothesized that CWS increases airway homogeneity and that these effects last for a period after removal of CWS.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eAfter performing baseline measurements (ventilation parameters, plethysmography, and volumetric capnography) participants with COPD (n\u0026thinsp;=\u0026thinsp;5) and healthy, sex-matched controls (n\u0026thinsp;=\u0026thinsp;5) underwent CWS. Measurements were repeated every 15 minutes for one hour following CWS. After CWS-removal measurements were repeated every 15 minutes for an additional hour. We related anatomic dead space, alveolar dead space, V\u003csub\u003eD\u003c/sub\u003e/V\u003csub\u003eT\u003c/sub\u003e, and slope of the capnogram to lung volume and tracked their changes over time.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eMoving from unstrapped to the CWS and to post-CWS condition, we saw an overall increase in the anatomic dead space (a surrogate with the size of the airway tree) for both groups with CWS and post-CWS (p\u0026thinsp;=\u0026thinsp;0.001). The capnographic slope is an indicator of airway uniformity. Post-CWS had a significant effect on both groups causing a decrease in the slope of the capnogram to lung volume ratio, showing a significant increase in airway homogeneity (p\u0026thinsp;=\u0026thinsp;0.03).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eCWS dilates airways quantified by the increase in dead space. The increase in airway homogeneity persists at least 45 minutes after strapping is removed. This indicates lasting benefits of CWS on airway function. The dilatation of airways and the improvement in airway homogeneity during and after CWS could facilitate enhanced delivery of inhaled therapies in COPD. CWS should be further investigated as a novel non-pharmacological treatment for COPD.\u003c/p\u003e","manuscriptTitle":"Research Article, Title: Chest Wall Strapping dilates airways and increases airway homogeneity in COPD","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-12 05:41:31","doi":"10.21203/rs.3.rs-8492362/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f240e259-71f0-4d45-8dce-b769fec321a9","owner":[],"postedDate":"January 12th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-01T07:13:00+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-12 05:41:31","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8492362","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8492362","identity":"rs-8492362","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}