Ultrasonography as a way of evaluating the diaphragm muscle in patients with chronic obstructive pulmonary disease.

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Bianca Carmo Figueira Silva, Diego Condesso de Abreu, Yves Raphael de Souza, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3246132/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: Diaphragmatic mobility (DM) may be reduced in chronic obstructive pulmonary disease (COPD) patients, but little is known about whether this mobility correlates with functional parameters, exercise capacity, and indicators of disease severity. Objective: To evaluate the DM of COPD patients and relate the findings with the distance achieved in the six-minute walk test (6MWT), forced expiratory volume in one second (FEV 1 ) % of predicted, residual volume (RV) % of predicted, and dyspnea. Methods: An observational cohort study was conducted to analyze DM through ultrasound during breathing, at rest and during deep inspiration and expiration. Results: It was included 49 COPD stable patients. There was a correlation between the DM measured between expiration and maximum inspiration with FEV 1 % of predicted (r = 0.36; p = 0.012), RV % of predicted (r = -0.42; p = 0.01), RV/Total Lung Capacity (TLC) (r = -0.61; p < 0.001), and distance reached in the 6MWT (r = 0.46; p = 0.001). In addition, patients with MRCm 2 (mean difference 13.20 + 4.6 mm; p = 0.0059), and patients with a BODE index 4 (47.89 mm) (mean difference 14.05 + 5.3 mm; 95% CI 25.09 to 3.01 mm). Conclusion: The results obtained suggest that DM is related to bronchial obstruction (FEV1), lung hyperinflation (RV and RV/TLC), exercise capacity, and the measurement of dyspnea, suggesting that it is an option for evaluating COPD patients. Diaphragm Ultrasonography COPD Diaphragmatic mobility Figures Figure 1 Figure 2 Figure 3 BACKGROUND Chronic Obstructive Pulmonary Disease (COPD) is one of the main causes of morbidity and mortality in adults and the elderly worldwide and is therefore considered an important public health problem. 1 , 2 The respiratory muscles in COPD patients show reduced strength and resistance, leading to the loss of the functional ability of these muscles. 3 This is due to changes in the rib cage, caused by lung hyperinflation, which alter the area of ​​biomechanical action of the diaphragm muscle, as well as to systemic factors and structural changes in the respiratory muscles. 4 The diaphragm is the main respiratory muscle, and in COPD patients, it shows important changes in the ability to contract and move. 4 Lung hyperinflation is one of the main alterations, and air trapping is the main factor limiting diaphragmatic mobility (DM) in these patients. 4 Although it is known that hyperinflation is the main cause of poor exercise tolerance in COPD patients, 5 little is known about the relationship of DM to the degree of bronchial obstruction, lung hyperinflation measured by whole-body plethysmography or its relationship with exercise capacity. This study aimed to evaluate DM in non-exacerbated COPD patients and verify the relationship with functional parameters and exercise capacity. METHODS A single-center, prospective observational cohort study was conducted to analyze diaphragmatic mobility through ultrasound during breathing at rest (at tidal volume) and during deep inspiration and expiration in patients with COPD. Patients from the pulmonology outpatient clinic were invited to participate in the research. The diagnosis of COPD was performed according to the criteria of the document Global Initiative for Chronic Obstructive Lung Disease (GOLD). 2 The exclusion criteria were use of orthosis or orthopedic limitations that limited the performance of the 6-minute walk test (6MWT); neurological and/or cognitive alterations; history of heart disease, heart attack less than 3 months ago, angina or uncontrolled high blood pressure; respiratory infections, exacerbation in the last 30 days; associated respiratory diseases such as asthma and pulmonary fibrosis; or inability to visualize the diaphragm through ultrasound due to anatomical factors. Subsequently, the patients performed the tests over 2 different days: on the first day, a medical questionnaire was filled out, including an assessment about the perception of dyspnea using the modified Medical Research Council scale (mMRC). 6 Patients were divided into two groups according to the MRCm scale. Patients with a score < 2 were considered not to have dyspnea (or to have few symptoms) and those with 2 or more points on the scale as having dyspnea. Later, the patient was requested to perform a spirometry to confirm the diagnosis of COPD, and finally, the 6MWT. Spirometry tests were performed on an HD CPL apparatus (nSpire Health Inc., Longmont, CO, USA) and followed American Thoracic Society (ATS) criteria. 7 Forced vital capacity (FVC), % of predicted, forced expiratory volume in one second (FEV1), % of predicted, and the FEV1/FVC ratio (%) were determined after 20 minutes of using the inhaled bronchodilator (salbutamol spray, at a dose of 400 mcg). 7 The theoretical predicted spirometry values ​​were those described by Knudson et al. 8 The 6-minute walk test (6MWT) was performed according to the guidelines established by the ATS in a 30-meters corridor, 9 and the predicted percentage was calculated using the equation of Enright PL & Sherrill DL. 10 On another day, in the same or in the following week, the patient was scheduled to return to undergo whole-body plethysmography and diaphragmatic ultrasound. Whole-body plethysmography was performed on an HD CPL apparatus (nSpire Health Inc., Longmont, CO, USA) and followed the standardization and interpretation of the ATS 11 , and the Neder equations were adopted. 12 In 2020, due to the COVID-19 pandemic, we stopped performing whole-body plethysmography on patients, according to the guidance received from the Brazilian Society of Pulmonology. Thus, patients recruited during or after 2020 did not perform this test. Exacerbation in the last few months was an exclusion criterion; so as not to create a classification bias, we decided not to use the clinical criteria. Thus, we did not use the A, B, and E GOLD classification but decided to assess severity by FEV 1 (GOLD spirometric classification), degree of dyspnea (MRCm 0, 1, 2, 3, and 4), and the BODE index. The literature describes the BODE Index as an assessment of the severity and mortality risk of patients with COPD. 13 This index not only includes the assessment of the degree of obstruction through FEV 1 , but also uses individual factors such as exercise tolerance (6MWD), BMI, and dyspnea (mMRC). The score obtained ranges from 0 to 10, and the higher the patient scores, the worse their condition. 13 The Index was calculated as originally proposed 13 and our patients were divided into two groups according to the results of the BODE Index ( ≤ 4 and > 4), considering that those with higher values were more severe. The ultrasound examination was performed by a single specialized and trained professional using a TOSHIBA device, model SSA-370ª Power Vision 6.000. To assess diaphragmatic mobility, the patient was placed in the supine position and a 3.5 MHz convex transducer was used, which allows the observation of deeper structures. This transducer was positioned in the right subcostal region, in the midclavicular line, with an incidence angle perpendicular to the craniocaudal axis and to the diaphragm. This was then identified through the hepatic acoustic window and its mobility was assessed by measuring, in millimeters (through M-mode) its craniocaudal displacement during breathing at rest (tidal volume). Then, the measurement was repeated considering the incursion performed from maximum inspiration (total lung capacity level) to maximum expiration (residual volume level). Three serial measurements were performed, and the highest value was considered and recorded for this research. The transducer was positioned to observe the entire movement of the diaphragmatic excursion, both in the tidal volume maneuver and in the maximal inspiratory and expiratory maneuver. This technique was previously described and is being widely used. 14 , 15 All examinations were performed on the right side to take advantage of the acoustic window of the liver, which facilitates visualization of the diaphragm. Statistical analysis was performed using the Prism 9.2 package. The normality of the sample was confirmed using the Kolmogorov–Smirnov test. Continuous data were presented as mean and standard deviation. The relationship between continuous variables was determined using Pearson's correlation. The difference between groups was determined by an unpaired t-test with a Welch correction. Results with p < 0.05 were considered significant. The study was approved by the Local Ethics Committee and numbered 82764817.8.0000.5259. Informed consent was obtained from all subjects, in compliance with the Helsinki Declaration. RESULTS Patient recruitment was performed as shown in the flowchart (Figure 1). The characteristics of the 49 patients included in the study are presented in Table 1. We then verified that 31 patients (63%) continued to complain of dyspnea despite pharmacological treatment and that 19 (39%) of them were classified as spirometric GOLD 3 or 4, evidencing the severity of the disease of the group studied. Table 1 shows the means and standard deviation referring to measures of diaphragmatic mobility at rest and during deep inspiration. When comparing the measurements of diaphragmatic mobility obtained with the patient at rest with those made during deep inspiration, we found a positive correlation (r = 0.63, 95% CI 0.43 to 0.78; r 2 = 0.4 and p < 0 .0001). Table 2 presents the correlations observed between the main variables studied and the DM evaluated at maximum inspiration and at rest. We expected that FEV 1 could have some correlation with DM, as in fact occurred when we assessed it during deep inspiration. Although Pearson's correlation was weak (r = 0.36 (95% CI 0.08 to 0.58), r 2 = 0.13; p = 0.012), it was statistically significant. The graph is shown in Figure 2A. We observed a moderate, but statistically significant, relationship between the 6MWD achieved and diaphragmatic mobility, both when measured at rest (Table 2) and at maximal inspiration (Table 2 and Figure 2B). Thus, the patients with the best performance in the field test are those with the highest DM values. We found that patients with greater hyperinflation had a lower DM when this measurement was performed with maximal inspiration; however, these data were not statistically significant when the DM study was performed with at-rest breathing. In Figure 2C, we present the correlation of the DM measurements during deep inspiration with the residual volume (RV) values and in Figure 2D, with the RV/total lung capacity (TLC) values. We found that most symptomatic patients (MRCm > 2) had lower diaphragmatic mobility (54.02 mm) measured at maximum inspiration than those without dyspnea (67.23 mm). The difference in means was 13.20 + 4.6 mm (95% CI 22.41 to 3.99 mm), and this difference was statistically significant (p = 0.0059), as illustrated in Figure 3. We found a statistical difference in these data (p = 0.015): the mean DM of patients with a BODE Index 4 was 47.89 mm. The difference between the means was 14.05 + 5.3 mm (95% CI 25.09 to 3.01 mm). The graph is shown in Figure 3. Table 1 - Patient data OUTCOMES VALUES Gender (M/F) 27/22 Age (years)* 69.27 + 7.55 Weight (kg)* 71.65 + 16.32 BMI (kg/m 2 )* 27.40 + 5.80 mMRC (n) 0 4 1 14 2 15 3 5 4 11 FEV 1 % of predicted* 53.86 + 21.09 6MWT Distance (m)* 384 + 96,91 Classification GOLD (n) 1 6 2 19 3 14 4 5 DM at rest (mm)* 31.10 + 11.87 deep inspiration (mm)* 59.41 + 17.91 Legend: BMI: Body Mass Index; MRCm: Dyspnea measured by modified Medical Research Council scale; FEV1: forced expiratory volume in one second; 6MWT: six-minute walk test; GOLD: spirometric classification as recommended in the document Global Initiative for Chronic Obstructive Lung Disease; DM: Diaphragmatic mobility; mm: millimeter. (*) Values are expressed as mean and standard deviation.. Table 2 - Correlation between the measurement of diaphragmatic mobility and functional tests Correlation between diaphragmatic mobility assessed in breathing at deep inspiration Outcome r CI 95% p-value FEV 1 (% predicted, post BD) 0.36 0.08 to 0.58 0.012 RV (% predicted) - 0.42 - 0.66 to 0.0 0.01 RV/TLC (%) - 0.61 - 0.78 to - 0.35 <0.001 6MWD (m) 0.46 0.20 to 0.66 0.001 Correlation between diaphragmatic mobility assessed in breathing at rest (tidal volume) Outcome r IC 95% p-value FEV 1 (% predicted, post BD) 0.08 - 0.20 to 0.35 0.56 (ns) RV (L) - 0.06 - 0.27 to - 0.37 0.74 (ns) RV/TLC (%) - 0.15 - 0.45 to 0.18 0.38 (ns) 6MWD (m) 0.30 0.02 to 0.50 0.03 Legend: FEV 1 : Forced Expiratory Volume in the first second; %: percentage; BD: bronchodilation; VR: residual volume; TLC: total lung capacity; 6MWD: six-minute walk distance; m: meter; CI: Confidence interval, ns: not significant DISCUSSION Due to the advancement of ultrasound in recent years, we have seen an increase in the number of diaphragm muscle studies using this tool, and in normal individuals, some authors have already determined the relationship between diaphragmatic excursion and pulmonary function. 15 , 16 , 17 However, the relationship between its mobility and lung function and severity in patients with COPD is not clear. We chose ultrasound as a way of evaluating the diaphragm muscle, which proved to be a very practical method of conducting the proposed research. The advantages of ultrasound over other imaging modalities include its portability, relatively low cost, and lack of contraindications. Our study was performed by a single professional trained in the management of ultrasound, and measurements were obtained with the patient in the supine position, with the transducer positioned in the right subcostal region, at the midclavicular line. This method has been described by most published articles and, for that reason, performed here. 14 , 15 , 16 , 17 Diaphragmatic mobility measurements were acquired with the patient breathing calmly (tidal volume) and after a deep inspiration maneuver (total lung capacity). All patients were able to perform the requested maneuvers properly, and we found it feasible to perform this test in COPD patients, even in those with severe disease. Although we observed a good correlation between the DM measurements performed at rest and during maximal inspiration (r = 0.63; 95% CI 0.43 to 0.78; r 2 = 0.4; p < 0.0001), the correlations between DM and functional parameters were negative when we used data collected from breathing at rest, while we observed that there was a correlation when the measurement was performed at the TLC level. This fact may be explained by the smaller craniocaudal displacement of the diaphragm muscle during breathing at rest. Thus, small changes in the measure may have impacted the statistical evaluations. Alternatively, we can infer that hyperinflation may be more apparent during deep inspiration. Lowering the diaphragm in these patients would allow ventilation at the tidal volume level to be less impacted, while the wider excursion, measured with maximal inspiration, would be more compromised. Although some authors have determined a relationship between DM and pulmonary function, not all studies point to the same results. While Scott et al reported that dynamic measurements using diaphragm ultrasonography do not correlate well with pulmonary volumes obtained by whole-body plethysmography 16 , Schulz et al published a recent article suggesting a good relationship between DM and residual volume 15 . Another study, published by Rocha et al. evaluated the DM of 25 COPD patients through chest radiography and related these findings to airway obstruction (FEV 1 ) and the perception of dyspnea measured by the mMRC scale. 18 However, they were unable to relate it to the measurement of daily activities and did not perform measurements using whole-body plethysmography to assess lung hyperinflation. A recent meta-analysis that included 8 articles evaluating DM by ultrasound in patients with COPD reported that the DM was lower in the severe COPD group than in the mild-to-moderate COPD group (WMD = 0.50; 95% CI: -0.01, 1.01; P = .06), but the difference was not significant. 19 Our study evaluated the relationship between DM and variables that measured airway obstruction, especially FEV 1 , and with lung hyperinflation, considering RV and RV/TLC ratio, and we observed a relationship with all of them when measurements were performed in deep inspiration but not with the patient breathing at rest. Our results suggest that patients with lower DM also have lower FEV1 , that is, they are more obstructive and have more hyperinflation. This data is confirmed by the literature. 15 , 19 The difference in the data obtained by Rocha can be explained, at least in part, by the methodology used. Ultrasonography is a more suitable method for studying DM than chest radiography performed in both phases of breathing. A recent study evaluated 55 COPD patients in the supine position using ultrasound to measure the DM on the right side of the chest, i.e., a measurement methodology like ours, and found that during the exacerbation the patients had a reduction of diaphragmatic excursion (40.4 mm to 30.8 mm). 20 These data suggest that diaphragmatic function may be influenced by factors other than those determined by the degree of bronchial obstruction. All our patients were stable at the time of evaluation; however, patients with the worst performance on the 6MWT and those who scored higher on the BODE had lower DM. Both the field test and the BODE index are measures that relate to the prognosis of patients and to mortality. 13 , 21 Yamaguti et al. evaluated the DM in 42 COPD patients and divided them into low ( ≤ 33.9 mm) and high ( ≥ 34 mm) diaphragmatic mobility. 22 These patients were followed for 2 years to assess mortality. The authors found that the 4 deaths that occurred in that period were detected in the group with the worst DM. Moreover, the BODE index and the distance achieved in the 6MWT performed at the beginning of the study were related to the DM. The authors suggested that low DM, as well as the 6MWT and the BODE index, may reflect a worse prognosis for patients with COPD. In our study, BODE index and 6MWT correlated with DM, suggesting that DM measured sonographically correlates with different parameters related to COPD severity. Other studies performed in COPD patients with lung hyperinflation reported a correlation between DM and distance covered on the 6MWT and a negative correlation with dyspnea. 23 Using the same methodology, our study, performed in stable COPD patients, not necessarily for hyperinflation, found similar results, confirming the relationship between exercise capacity and DM. Interestingly, the study by Rocha et al., using radiography in forced inhalations and exhalation, correlated the findings of DM measurements with the dyspnea assessed by the MRCm scale. 18 Likewise, our study, which evaluated DM through ultrasound, also reached the same results. We found that most symptomatic patients had less diaphragmatic mobility (p = 0.0059). Our study has some limitations that should be noted. The study was conducted in a single tertiary center, and the patients had a higher than average illness severity. Whole-body plethysmography was only performed on 36 of the 49 patients analyzed, as we were restricted from doing so during the period of the COVID-19 pandemic. We must also consider that we did not follow the patients to assess prognosis. Thus, despite the positive results, we are aware of the need for further studies to confirm the data. CONCLUSION The measurement of diaphragmatic excursion obtained during deep inspiration was correlated with airway obstruction (FEV 1 ) and pulmonary hyperinflation (RV and RV/CPT). This measurement was also related to dyspnea as well as functional capacity assessed by the 6MWT and the BODE index. Thus, this measurement could be used as a biomarker of severity in patients with COPD. Declarations All authors have seen and agreed with the contents of the manuscript, meet criteria for authorship and declare no conflicts of interest. We certify that the manuscript has not been published, is not under review at any other publication, and, if accepted, will not be published elsewhere in any language. The paper has been professionally proofread by PRS and we will be delighted to provide you with verification if necessary. The study was approved by Local Ethics Committee and numbered 82764817.8.0000.5259. All patients signed an Informed Consent before study procedures. The study was funded by FAPERJ (Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro). The authors also confirm the presence of shared data and inform that data can be accessed. In this case, please contact Dr. Cláudia Henrique da Costa, email [email protected] . None of the authors have conflicts of interesting related to this manuscript. Ethics approval and consent to participate The study was approved by the Local Ethics Committee (Comitê de Ética do Hospital Universitário Pedro Ernesto) and numbered 82764817.8.0000.5259. All individuals signed a free will and information consent form before they became subjects of the study procedures, in compliance with the Helsinki Declaration Consent for publication Not Applicable Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests Funding The study was funded by FAPERJ (Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro). Authors' contributions All authors have seen and agreed with the contents of the manuscript and meet criteria for authorship. First author- BCSF – Made substantial contributions to the conception of the work, acquisition of data for the work; drafting the work; approved the final version to be published, and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. DCA – Made substantial contributions to the acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. YRS - Made substantial contributions to the design of the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. MF - Made substantial contributions to the acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JFM - Made substantial contributions to the acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. TTM - Made substantial contributions to the conception and acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. RR - Made substantial contributions to the conception of the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. CHC (Corresponding author) - Made substantial contributions to the conception and design of the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Acknowledgements Not Applicable References Mannino DM, Tal-Singer R. Long-term trends of COPD mortality: Gaps and opportunities. Respirology. 2022 Nov;27(11):914-915. doi: 10.1111/resp.14334. Epub 2022 Aug 2. PMID: 35916275. Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease 2023 report. Vázquez-Gandullo E, Hidalgo-Molina A, Montoro-Ballesteros F, Morales-González M, Muñoz-Ramírez I, Arnedillo-Muñoz A. 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An TJ, Yoo YJ, Lim JU, Seo W, Park CK, Rhee CK, Yoon HK. Diaphragm ultrasound is an imaging biomarker that distinguishes exacerbation status from stable chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis 2022;4(17):3-12. Agarwala P, Salzman SH. Six-Minute Walk Test: Clinical Role, Technique, Coding, and Reimbursement. Chest. 2020 Mar;157(3):603-611. doi: 10.1016/j.chest.2019.10.014. Epub 2019 Nov 2. PMID: 31689414; PMCID: PMC7609960. Yamaguti WPDS, Paulin E, Salge JM, Chammas MC, Cukier A, Carvalho CRFD. Diaphragmatic dysfunction and mortality in patients with COPD. J Bras Pneumol 2009;35:1174-81. Paulin E, Yamaguti WP, Chammas MC, Shibao S, Stelmach R, Cukier A, Carvalho CR. Influence of diaphragmatic mobility on exercise tolerance and dyspnea in patients with COPD. Respir Med. 2007 Oct;101(10):2113-8. doi: 10.1016/j.rmed.2007.05.024. Epub 2007 Jul 20. PMID: 17644365. Additional Declarations No competing interests reported. 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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-3246132","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":230426178,"identity":"8cc83885-b521-4c42-a21f-f35b35a9ddc9","order_by":0,"name":"Bianca Carmo Figueira Silva","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Bianca","middleName":"Carmo Figueira","lastName":"Silva","suffix":""},{"id":230426179,"identity":"a0b2c1f9-dfa1-4d45-b51c-a647dac7f200","order_by":1,"name":"Diego Condesso de Abreu","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Diego","middleName":"Condesso","lastName":"de Abreu","suffix":""},{"id":230426180,"identity":"7a1e8fd4-8b80-4f14-a3c1-f6e35b7530bd","order_by":2,"name":"Yves Raphael de Souza","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Yves","middleName":"Raphael","lastName":"de Souza","suffix":""},{"id":230426181,"identity":"39517d17-15e4-48f6-b0ea-f5d089d5f713","order_by":3,"name":"Manoele Figueiredo","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Manoele","middleName":"","lastName":"Figueiredo","suffix":""},{"id":230426182,"identity":"061732cb-2c27-467f-ad5d-84b4e2fcb77e","order_by":4,"name":"Joseane Felix Macêdo","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Joseane","middleName":"Felix","lastName":"Macêdo","suffix":""},{"id":230426183,"identity":"99ff4fd7-fc63-4544-adca-d0696448b800","order_by":5,"name":"Thiago Thomaz Mafort","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Thiago","middleName":"Thomaz","lastName":"Mafort","suffix":""},{"id":230426184,"identity":"a9c2d678-f9fa-42d1-abbe-04b6e53b658a","order_by":6,"name":"Rogério Rufino","email":"","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":false,"prefix":"","firstName":"Rogério","middleName":"","lastName":"Rufino","suffix":""},{"id":230426185,"identity":"7ea35105-1b7f-4619-96cc-50d8976e251e","order_by":7,"name":"Cláudia Henrique da Costa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYJCDxAdAgoePKLUHIFSyAUgLGyla2CTAJCHV/O2HD3/+UMOQ2C994Fnl1xw7GTYG5oePbuDRInEmLU3iwDGGxJl9CWm3ZbclAx3GZmycg0eLgQSPGcMBNobEDWcY0m5LbmMGauFhkyagxfjDgX8MifuBWoolt9UTpcVA4mAb0BYehjTGj9sOE9YC9svZPgnjGWcYkqUZtx3nYWMm4BdQiH2o+GYj29/Dk/jx57Zqe3725oeP8WmBWQbEPAnMPCA2M2HlMMB+gPEH8apHwSgYBaNgBAEAAuRDKYmAEdEAAAAASUVORK5CYII=","orcid":"","institution":"Rio de Janeiro State University","correspondingAuthor":true,"prefix":"","firstName":"Cláudia","middleName":"Henrique da","lastName":"Costa","suffix":""}],"badges":[],"createdAt":"2023-08-08 15:44:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3246132/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3246132/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":42720847,"identity":"4c2a38c6-168b-416c-9fd5-1910f123ba5f","added_by":"auto","created_at":"2023-09-06 14:29:07","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":58535,"visible":true,"origin":"","legend":"\u003cp\u003ePatient recruitment flowchart\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(*) Procedures performed: Assessment of dyspnea using the modified Medical Research Council scale, diaphragmatic mobility through ultrasound, spirometry, and six-minute walk test. In 2020, due to the COVID-19 pandemic, we stopped performing whole-body plethysmography on patients, according to the guidance received from the Brazilian Society of Pulmonology. Thus, the data presented on these measures account for the first 36 patients recruited before the pandemic, who had already performed all study procedures.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-3246132/v1/7a98a5299439b325112e003e.png"},{"id":42720848,"identity":"457b6297-0acd-484f-9dec-de9c2f6ca270","added_by":"auto","created_at":"2023-09-06 14:29:07","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":132758,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation of diaphragmatic mobility measured in deep inspiration with functional variables\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLegend: FEV1: Forced Expiratory Volume in the first second; %: percentage; BD: bronchodilation; VR: residual volume; TLC: total lung capacity; 6MWD: six-minute walk distance\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-3246132/v1/8feba9362344c5e5645bcbd9.png"},{"id":42720849,"identity":"f2f8cd6e-c079-407f-983f-b845bdd0dc11","added_by":"auto","created_at":"2023-09-06 14:29:07","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":137040,"visible":true,"origin":"","legend":"\u003cp\u003eDiaphragmatic mobility according to BODE index and dyspnea\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLegend: DM: Diaphragmatic mobility; mMRC: modified Medical Research Council scale, BODE: Body mass index, airway Obstruction, Dyspnea, and Exercise capacity\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-3246132/v1/0929f5fe81fa6740a9610661.png"},{"id":58274971,"identity":"57637bd2-e3aa-4c46-aeb5-cbf99c40e8de","added_by":"auto","created_at":"2024-06-13 09:31:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":696720,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3246132/v1/5a340eec-caa8-47f8-bff8-0aa5be1eec00.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eUltrasonography as a way of evaluating the diaphragm muscle in patients with chronic obstructive pulmonary disease.\u003c/p\u003e","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eChronic Obstructive Pulmonary Disease (COPD) is one of the main causes of morbidity and mortality in adults and the elderly worldwide and is therefore considered an important public health problem.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e The respiratory muscles in COPD patients show reduced strength and resistance, leading to the loss of the functional ability of these muscles.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e This is due to changes in the rib cage, caused by lung hyperinflation, which alter the area of ​​biomechanical action of the diaphragm muscle, as well as to systemic factors and structural changes in the respiratory muscles.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e The diaphragm is the main respiratory muscle, and in COPD patients, it shows important changes in the ability to contract and move.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e Lung hyperinflation is one of the main alterations, and air trapping is the main factor limiting diaphragmatic mobility (DM) in these patients.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e Although it is known that hyperinflation is the main cause of poor exercise tolerance in COPD patients,\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e little is known about the relationship of DM to the degree of bronchial obstruction, lung hyperinflation measured by whole-body plethysmography or its relationship with exercise capacity. This study aimed to evaluate DM in non-exacerbated COPD patients and verify the relationship with functional parameters and exercise capacity.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eA single-center, prospective observational cohort study was conducted to analyze diaphragmatic mobility through ultrasound during breathing at rest (at tidal volume) and during deep inspiration and expiration in patients with COPD. Patients from the pulmonology outpatient clinic were invited to participate in the research. The diagnosis of COPD was performed according to the criteria of the document Global Initiative for Chronic Obstructive Lung Disease (GOLD).\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e The exclusion criteria were use of orthosis or orthopedic limitations that limited the performance of the 6-minute walk test (6MWT); neurological and/or cognitive alterations; history of heart disease, heart attack less than 3 months ago, angina or uncontrolled high blood pressure; respiratory infections, exacerbation in the last 30 days; associated respiratory diseases such as asthma and pulmonary fibrosis; or inability to visualize the diaphragm through ultrasound due to anatomical factors.\u003c/p\u003e \u003cp\u003eSubsequently, the patients performed the tests over 2 different days: on the first day, a medical questionnaire was filled out, including an assessment about the perception of dyspnea using the modified Medical Research Council scale (mMRC).\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e Patients were divided into two groups according to the MRCm scale. Patients with a score\u0026thinsp;\u0026lt;\u0026thinsp;2 were considered not to have dyspnea (or to have few symptoms) and those with 2 or more points on the scale as having dyspnea. Later, the patient was requested to perform a spirometry to confirm the diagnosis of COPD, and finally, the 6MWT. Spirometry tests were performed on an HD CPL apparatus (nSpire Health Inc., Longmont, CO, USA) and followed American Thoracic Society (ATS) criteria.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Forced vital capacity (FVC), % of predicted, forced expiratory volume in one second (FEV1), % of predicted, and the FEV1/FVC ratio (%) were determined after 20 minutes of using the inhaled bronchodilator (salbutamol spray, at a dose of 400 mcg).\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e The theoretical predicted spirometry values ​​were those described by Knudson et al.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e The 6-minute walk test (6MWT) was performed according to the guidelines established by the ATS in a 30-meters corridor,\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e and the predicted percentage was calculated using the equation of Enright PL \u0026amp; Sherrill DL.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eOn another day, in the same or in the following week, the patient was scheduled to return to undergo whole-body plethysmography and diaphragmatic ultrasound. Whole-body plethysmography was performed on an HD CPL apparatus (nSpire Health Inc., Longmont, CO, USA) and followed the standardization and interpretation of the ATS\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e, and the Neder equations were adopted.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e In 2020, due to the COVID-19 pandemic, we stopped performing whole-body plethysmography on patients, according to the guidance received from the Brazilian Society of Pulmonology. Thus, patients recruited during or after 2020 did not perform this test.\u003c/p\u003e \u003cp\u003eExacerbation in the last few months was an exclusion criterion; so as not to create a classification bias, we decided not to use the clinical criteria. Thus, we did not use the A, B, and E GOLD classification but decided to assess severity by FEV\u003csub\u003e1\u003c/sub\u003e (GOLD spirometric classification), degree of dyspnea (MRCm 0, 1, 2, 3, and 4), and the BODE index. The literature describes the BODE Index as an assessment of the severity and mortality risk of patients with COPD.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e This index not only includes the assessment of the degree of obstruction through FEV\u003csub\u003e1\u003c/sub\u003e, but also uses individual factors such as exercise tolerance (6MWD), BMI, and dyspnea (mMRC). The score obtained ranges from 0 to 10, and the higher the patient scores, the worse their condition.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e The Index was calculated as originally proposed\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e and our patients were divided into two groups according to the results of the BODE Index (\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026le;\u003c/span\u003e\u0026thinsp;4 and \u0026gt;\u0026thinsp;4), considering that those with higher values were more severe.\u003c/p\u003e \u003cp\u003eThe ultrasound examination was performed by a single specialized and trained professional using a TOSHIBA device, model SSA-370\u0026ordf; Power Vision 6.000. To assess diaphragmatic mobility, the patient was placed in the supine position and a 3.5 MHz convex transducer was used, which allows the observation of deeper structures. This transducer was positioned in the right subcostal region, in the midclavicular line, with an incidence angle perpendicular to the craniocaudal axis and to the diaphragm. This was then identified through the hepatic acoustic window and its mobility was assessed by measuring, in millimeters (through M-mode) its craniocaudal displacement during breathing at rest (tidal volume). Then, the measurement was repeated considering the incursion performed from maximum inspiration (total lung capacity level) to maximum expiration (residual volume level). Three serial measurements were performed, and the highest value was considered and recorded for this research. The transducer was positioned to observe the entire movement of the diaphragmatic excursion, both in the tidal volume maneuver and in the maximal inspiratory and expiratory maneuver. This technique was previously described and is being widely used.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e All examinations were performed on the right side to take advantage of the acoustic window of the liver, which facilitates visualization of the diaphragm.\u003c/p\u003e \u003cp\u003eStatistical analysis was performed using the Prism 9.2 package. The normality of the sample was confirmed using the Kolmogorov\u0026ndash;Smirnov test. Continuous data were presented as mean and standard deviation. The relationship between continuous variables was determined using Pearson's correlation. The difference between groups was determined by an unpaired t-test with a Welch correction. Results with p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered significant.\u003c/p\u003e \u003cp\u003e The study was approved by the Local Ethics Committee and numbered 82764817.8.0000.5259. Informed consent was obtained from all subjects, in compliance with the Helsinki Declaration.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e "},{"header":"RESULTS","content":"\u003cp\u003ePatient recruitment was performed as shown in the flowchart (Figure 1). The characteristics of the 49 patients included in the study are presented in Table 1. We then verified that 31 patients (63%) continued to complain of dyspnea despite pharmacological treatment and that 19 (39%) of them were classified as spirometric GOLD 3 or 4, evidencing the severity of the disease of the group studied.\u003c/p\u003e\n\u003cp\u003eTable 1 shows the means and standard deviation referring to measures of diaphragmatic mobility at rest and during deep inspiration. When comparing the measurements of diaphragmatic mobility obtained with the patient at rest with those made during deep inspiration, we found a positive correlation (r = 0.63, 95% CI 0.43 to 0.78; r\u003csup\u003e2\u003c/sup\u003e = 0.4 and p \u0026lt; 0 .0001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 2 presents the correlations observed between the main variables studied and the DM evaluated at maximum inspiration and at rest. We expected that FEV\u003csub\u003e1\u003c/sub\u003e could have some correlation with DM, as in fact occurred when we assessed it during deep inspiration. Although Pearson\u0026apos;s correlation was weak (r = 0.36 (95% CI 0.08 to 0.58), r\u003csup\u003e2\u003c/sup\u003e = 0.13; p = 0.012), it was statistically significant. The graph is shown in Figure 2A.\u003c/p\u003e\n\u003cp\u003eWe observed a moderate, but statistically significant, relationship between the 6MWD achieved and diaphragmatic mobility, both when measured at rest (Table 2) and at maximal inspiration (Table 2 and Figure 2B). Thus, the patients with the best performance in the field test are those with the highest DM values.\u003c/p\u003e\n\u003cp\u003eWe found that patients with greater hyperinflation had a lower DM when this measurement was performed with maximal inspiration; however, these data were not statistically significant when the DM study was performed with at-rest breathing. In Figure 2C, we present the correlation of the DM measurements during deep inspiration with the residual volume (RV) values and in Figure 2D, with the RV/total lung capacity (TLC) values.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe found that most symptomatic patients (MRCm \u003cu\u003e\u0026gt;\u003c/u\u003e2) had lower diaphragmatic mobility (54.02 mm) measured at maximum inspiration than those without dyspnea (67.23 mm). The difference in means was 13.20 \u003cu\u003e+\u003c/u\u003e 4.6 mm (95% CI 22.41 to 3.99 mm), and this difference was statistically significant (p = 0.0059), as illustrated in Figure 3.\u003c/p\u003e\n\u003cp\u003eWe found a statistical difference in these data (p = 0.015): the mean DM of patients with a BODE Index \u003cu\u003e\u0026lt;\u003c/u\u003e4 was 61.95 mm, and that of patients with a result \u0026gt;4 was 47.89 mm. The difference between the means was 14.05 \u003cu\u003e+\u003c/u\u003e 5.3 mm (95% CI 25.09 to 3.01 mm). The graph is shown in Figure 3.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1 -\u0026nbsp;\u003c/strong\u003ePatient data\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"463\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"61.33909287257019%\" colspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eOUTCOMES\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e\u003cstrong\u003eVALUES\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"61.33909287257019%\" colspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003eGender (M/F)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e27/22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"61.33909287257019%\" colspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003eAge (years)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e69.27 \u003cu\u003e+\u003c/u\u003e 7.55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"61.33909287257019%\" colspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003eWeight (kg)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e71.65 \u003cu\u003e+\u003c/u\u003e 16.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"61.33909287257019%\" colspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e27.40 \u003cu\u003e+\u003c/u\u003e 5.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.03023758099352%\" rowspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003emMRC (n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.30885529157668%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.03023758099352%\"\u003e\n \u003cp\u003e\u003cstrong\u003eFEV\u003csub\u003e1\u003c/sub\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.30885529157668%\"\u003e\n \u003cp\u003e% of predicted*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e53.86 \u003cu\u003e+\u003c/u\u003e 21.09\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.03023758099352%\"\u003e\n \u003cp\u003e\u003cstrong\u003e6MWT\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.30885529157668%\"\u003e\n \u003cp\u003eDistance (m)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e384 \u003cu\u003e+\u003c/u\u003e 96,91\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.03023758099352%\" rowspan=\"4\"\u003e\n \u003cp\u003e\u003cstrong\u003eClassification GOLD (n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.30885529157668%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.41551246537396%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.58448753462604%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.03023758099352%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eDM\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"39.30885529157668%\"\u003e\n \u003cp\u003eat rest (mm)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e31.10 \u003cu\u003e+\u003c/u\u003e 11.87\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.03023758099352%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"39.30885529157668%\"\u003e\n \u003cp\u003edeep inspiration (mm)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.66090712742981%\"\u003e\n \u003cp\u003e59.41 \u003cu\u003e+\u003c/u\u003e 17.91\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eLegend:\u0026nbsp;\u003c/strong\u003eBMI: Body Mass Index; MRCm: Dyspnea measured by modified Medical Research Council scale; FEV1:\u0026nbsp;forced expiratory volume in one second;\u0026nbsp;6MWT:\u0026nbsp;six-minute walk test;\u0026nbsp;GOLD: spirometric classification as recommended in the document Global Initiative for Chronic Obstructive Lung Disease; DM:\u0026nbsp;Diaphragmatic mobility; mm: millimeter.\u0026nbsp;(*) Values are expressed as mean and standard deviation..\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2 -\u0026nbsp;\u003c/strong\u003eCorrelation between the measurement of diaphragmatic mobility and functional tests\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCorrelation between diaphragmatic mobility assessed in breathing at deep inspiration\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eOutcome\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003er\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCI 95%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003eFEV\u003csub\u003e1\u0026nbsp;\u003c/sub\u003e(% predicted, post BD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e0.08 to 0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.012\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003eRV (% predicted)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.66 to 0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.01\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003eRV/TLC (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.78 to - 0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003e6MWD (m)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e0.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e0.20 to 0.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCorrelation between diaphragmatic mobility assessed in breathing at rest (tidal volume)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eOutcome\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003er\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eIC 95%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003eFEV\u003csub\u003e1\u0026nbsp;\u003c/sub\u003e(% predicted, post BD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.20 to 0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e0.56 (ns)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003eRV (L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.27 to - 0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e0.74 (ns)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003eRV/TLC (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e- 0.45 to 0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e0.38 (ns)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.3886925795053%\" valign=\"top\"\u003e\n \u003cp\u003e6MWD (m)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.25441696113074%\" valign=\"top\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.268551236749115%\" valign=\"top\"\u003e\n \u003cp\u003e0.02 to 0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.08833922261484%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.03\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e FEV\u003csub\u003e1\u003c/sub\u003e: Forced Expiratory Volume in the first second; %: percentage; BD: bronchodilation; VR: residual volume; TLC: total lung capacity; 6MWD: six-minute walk distance; m: meter; CI: Confidence interval, ns: not significant\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eDue to the advancement of ultrasound in recent years, we have seen an increase in the number of diaphragm muscle studies using this tool, and in normal individuals, some authors have already determined the relationship between diaphragmatic excursion and pulmonary function.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e However, the relationship between its mobility and lung function and severity in patients with COPD is not clear. We chose ultrasound as a way of evaluating the diaphragm muscle, which proved to be a very practical method of conducting the proposed research. The advantages of ultrasound over other imaging modalities include its portability, relatively low cost, and lack of contraindications. Our study was performed by a single professional trained in the management of ultrasound, and measurements were obtained with the patient in the supine position, with the transducer positioned in the right subcostal region, at the midclavicular line. This method has been described by most published articles and, for that reason, performed here.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e Diaphragmatic mobility measurements were acquired with the patient breathing calmly (tidal volume) and after a deep inspiration maneuver (total lung capacity). All patients were able to perform the requested maneuvers properly, and we found it feasible to perform this test in COPD patients, even in those with severe disease. Although we observed a good correlation between the DM measurements performed at rest and during maximal inspiration (r\u0026thinsp;=\u0026thinsp;0.63; 95% CI 0.43 to 0.78; r\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.4; p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001), the correlations between DM and functional parameters were negative when we used data collected from breathing at rest, while we observed that there was a correlation when the measurement was performed at the TLC level. This fact may be explained by the smaller craniocaudal displacement of the diaphragm muscle during breathing at rest. Thus, small changes in the measure may have impacted the statistical evaluations. Alternatively, we can infer that hyperinflation may be more apparent during deep inspiration. Lowering the diaphragm in these patients would allow ventilation at the tidal volume level to be less impacted, while the wider excursion, measured with maximal inspiration, would be more compromised.\u003c/p\u003e \u003cp\u003eAlthough some authors have determined a relationship between DM and pulmonary function, not all studies point to the same results. While Scott et al reported that dynamic measurements using diaphragm ultrasonography do not correlate well with pulmonary volumes obtained by whole-body plethysmography\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e, Schulz et al published a recent article suggesting a good relationship between DM and residual volume\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Another study, published by Rocha et al. evaluated the DM of 25 COPD patients through chest radiography and related these findings to airway obstruction (FEV\u003csub\u003e1\u003c/sub\u003e) and the perception of dyspnea measured by the mMRC scale.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e However, they were unable to relate it to the measurement of daily activities and did not perform measurements using whole-body plethysmography to assess lung hyperinflation. A recent meta-analysis that included 8 articles evaluating DM by ultrasound in patients with COPD reported that the DM was lower in the severe COPD group than in the mild-to-moderate COPD group (WMD\u0026thinsp;=\u0026thinsp;0.50; 95% CI: -0.01, 1.01; P\u0026thinsp;=\u0026thinsp;.06), but the difference was not significant.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eOur study evaluated the relationship between DM and variables that measured airway obstruction, especially FEV\u003csub\u003e1\u003c/sub\u003e, and with lung hyperinflation, considering RV and RV/TLC ratio, and we observed a relationship with all of them when measurements were performed in deep inspiration but not with the patient breathing at rest. Our results suggest that patients with lower DM also have lower \u003csub\u003eFEV1\u003c/sub\u003e, that is, they are more obstructive and have more hyperinflation. This data is confirmed by the literature.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e The difference in the data obtained by Rocha can be explained, at least in part, by the methodology used. Ultrasonography is a more suitable method for studying DM than chest radiography performed in both phases of breathing.\u003c/p\u003e \u003cp\u003eA recent study evaluated 55 COPD patients in the supine position using ultrasound to measure the DM on the right side of the chest, i.e., a measurement methodology like ours, and found that during the exacerbation the patients had a reduction of diaphragmatic excursion (40.4 mm to 30.8 mm).\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e These data suggest that diaphragmatic function may be influenced by factors other than those determined by the degree of bronchial obstruction. All our patients were stable at the time of evaluation; however, patients with the worst performance on the 6MWT and those who scored higher on the BODE had lower DM. Both the field test and the BODE index are measures that relate to the prognosis of patients and to mortality.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e Yamaguti et al. evaluated the DM in 42 COPD patients and divided them into low (\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026le;\u003c/span\u003e\u0026thinsp;33.9 mm) and high (\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;34 mm) diaphragmatic mobility.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e These patients were followed for 2 years to assess mortality. The authors found that the 4 deaths that occurred in that period were detected in the group with the worst DM. Moreover, the BODE index and the distance achieved in the 6MWT performed at the beginning of the study were related to the DM. The authors suggested that low DM, as well as the 6MWT and the BODE index, may reflect a worse prognosis for patients with COPD.\u003c/p\u003e \u003cp\u003eIn our study, BODE index and 6MWT correlated with DM, suggesting that DM measured sonographically correlates with different parameters related to COPD severity. Other studies performed in COPD patients with lung hyperinflation reported a correlation between DM and distance covered on the 6MWT and a negative correlation with dyspnea.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e Using the same methodology, our study, performed in stable COPD patients, not necessarily for hyperinflation, found similar results, confirming the relationship between exercise capacity and DM.\u003c/p\u003e \u003cp\u003eInterestingly, the study by Rocha et al., using radiography in forced inhalations and exhalation, correlated the findings of DM measurements with the dyspnea assessed by the MRCm scale.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e Likewise, our study, which evaluated DM through ultrasound, also reached the same results. We found that most symptomatic patients had less diaphragmatic mobility (p\u0026thinsp;=\u0026thinsp;0.0059).\u003c/p\u003e \u003cp\u003eOur study has some limitations that should be noted. The study was conducted in a single tertiary center, and the patients had a higher than average illness severity. Whole-body plethysmography was only performed on 36 of the 49 patients analyzed, as we were restricted from doing so during the period of the COVID-19 pandemic. We must also consider that we did not follow the patients to assess prognosis. Thus, despite the positive results, we are aware of the need for further studies to confirm the data.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThe measurement of diaphragmatic excursion obtained during deep inspiration was correlated with airway obstruction (FEV\u003csub\u003e1\u003c/sub\u003e) and pulmonary hyperinflation (RV and RV/CPT). This measurement was also related to dyspnea as well as functional capacity assessed by the 6MWT and the BODE index. Thus, this measurement could be used as a biomarker of severity in patients with COPD.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAll authors have seen and agreed with the contents of the manuscript, meet criteria for authorship and declare no conflicts of interest.\u003c/p\u003e\n\u003cp\u003eWe certify that the manuscript has not been published, is not under review at any other publication, and, if accepted, will not be published elsewhere in any language. The paper has been professionally proofread by PRS and we will be delighted to provide you with verification if necessary.\u003c/p\u003e\n\u003cp\u003eThe study was approved by Local Ethics Committee and numbered 82764817.8.0000.5259. All patients signed an Informed Consent before study procedures.\u003c/p\u003e\n\u003cp\u003eThe study was funded by FAPERJ (Funda\u0026ccedil;\u0026atilde;o de Amparo \u0026agrave; Pesquisa do Estado do Rio de Janeiro).\u003c/p\u003e\n\u003cp\u003eThe authors also confirm the presence of shared data and inform that data can be accessed. In this case, please contact Dr. Cl\u0026aacute;udia Henrique da Costa, email [email protected]. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNone of the authors have conflicts of interesting related to this manuscript.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe study was approved by the Local Ethics Committee (Comit\u0026ecirc; de \u0026Eacute;tica do Hospital Universit\u0026aacute;rio Pedro Ernesto) and numbered 82764817.8.0000.5259. All individuals signed a free will and information consent form before they became subjects of the study procedures, in compliance with the Helsinki Declaration\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot Applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThe study was funded by FAPERJ (Funda\u0026ccedil;\u0026atilde;o de Amparo \u0026agrave; Pesquisa do Estado do Rio de Janeiro).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eAll authors have seen and agreed with the contents of the manuscript and meet criteria for authorship.\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eFirst author- BCSF\u003c/strong\u003e \u0026ndash; Made substantial contributions to the conception of the work, acquisition of data for the work; drafting the work; approved the final version to be published, and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eDCA\u003c/strong\u003e \u0026ndash; Made substantial contributions to the acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eYRS\u003c/strong\u003e - Made substantial contributions to the design of the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eMF\u003c/strong\u003e - Made substantial contributions to the acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eJFM\u003c/strong\u003e - Made substantial contributions to the acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eTTM\u003c/strong\u003e - Made substantial contributions to the conception and acquisition of data for the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eRR\u003c/strong\u003e - Made substantial contributions to the conception of the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eCHC\u003c/strong\u003e (Corresponding author) - Made substantial contributions to the conception and design of the work; reviewed the draft critically, approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eMannino DM, Tal-Singer R. Long-term trends of COPD mortality: Gaps and opportunities. Respirology. 2022 Nov;27(11):914-915. doi: 10.1111/resp.14334. Epub 2022 Aug 2. PMID: 35916275.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eGlobal Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease 2023 report.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eV\u0026aacute;zquez-Gandullo E, Hidalgo-Molina A, Montoro-Ballesteros F, Morales-Gonz\u0026aacute;lez M, Mu\u0026ntilde;oz-Ram\u0026iacute;rez I, Arnedillo-Mu\u0026ntilde;oz A. Inspiratory Muscle Training in Patients with Chronic Obstructive Pulmonary Disease (COPD) as Part of a Respiratory Rehabilitation Program Implementation of Mechanical Devices: A Systematic Review. Int J Environ Res Public Health. 2022 May 3;19(9):5564. doi: 10.3390/ijerph19095564. PMID: 35564959; PMCID: PMC9099727.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eScaramuzzo G, Ottaviani I, Volta CA, Spadaro S. Mechanical ventilation and COPD: from pathophysiology to ventilatory management. Minerva Med. 2022 Jun;113(3):460-470. doi: 10.23736/S0026-4806.22.07974-5. PMID: 35856181.\u003c/li\u003e\n \u003cli\u003eD\u0026apos;Ascanio M, Viccaro F, Calabr\u0026ograve; N, Guerrieri G, Salvucci C, Pizzirusso D, Mancini R, De Vitis C, Pezzuto A, Ricci A. Assessing Static Lung Hyperinflation by Whole-Body Plethysmography, Helium Dilution, and Impulse Oscillometry System (IOS) in Patients with COPD. Int J Chron Obstruct Pulmon Dis. 2020 Oct 21;15:2583-2589. doi: 10.2147/COPD.S264261.\u0026nbsp;PMID: 33116475; PMCID: PMC7585810.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eTsiligianni IG, Alma HJ, de Jong C, Jelusic D, Wittmann M, Schuler M, Schultz K, Kollen BJ, van der Molen T, Kocks JW. Investigating sensitivity, specificity, and area under the curve of the Clinical COPD Questionnaire, COPD Assessment Test, and Modified Medical Research Council scale according to GOLD using St George\u0026apos;s Respiratory Questionnaire cutoff 25 (and 20) as reference. Int J Chron Obstruct Pulmon Dis. 2016 May 18;11:1045-52. doi: 10.2147/COPD.S99793.\u0026nbsp;PMID: 27274226; PMCID: PMC4876797.\u003c/li\u003e\n \u003cli\u003eStanojevic S, Kaminsky DA, Miller MR, Thompson B, Aliverti A, Barjaktarevic I, et al. ERS/ATS technical standard on interpretive strategies for routine lung function tests. Eur Respir J. 2022;60(1):2101499.\u003c/li\u003e\n \u003cli\u003eKnudson RJ, Lebowitz MD, Holdberg CJ, Burrows B. Changes in normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis 1983;127:725-34.\u003c/li\u003e\n \u003cli\u003eHolland AE, Spruit MA, Troosters T, Puhan MA, Pepin V, Saey D, McCormack MC, Carlin BW, Sciurba FC, Pitta F, Wanger J, MacIntyre N, Kaminsky DA, Culver BH, Revill SM, Hernandes NA, Andrianopoulos V, Camillo CA, Mitchell KE, Lee AL, Hill CJ, Singh SJ.\u0026nbsp;An official European Respiratory Society/ American Thoracic Society technical standard: field walking tests in chronic respiratory disease. Eur Respir J 2014;44:1428-46.\u003c/li\u003e\n \u003cli\u003eEnright PL, Sherrill DL. Reference equations for the six minute walk in health adults. Am J Respir Crit Care Med 1998;158:1384-7.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAmerican Thoracic Society. Lung function testing: selection of reference values and interpretative strategies. Am Rev Respir Dis 1991;144(5):1202-18.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eNeder JA, Andreoni S, Castelo-Filho A, Nery LE.\u0026nbsp;Reference values for lung function tests. I. Static volumes. Braz J Med Biol Res. 1999;32(6):703-717.\u003c/li\u003e\n \u003cli\u003eCelli BR, Cote CG, Marin JM, Casanova C, Montes de Oca M, Mendez RA, Pinto Plata V, Cabral HJ.\u0026nbsp;The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease, N Engl J Med 2004;350(10):1005-12.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eVivier E, Mekontso Dessap A, Dimassi S, Vargas F, Lyazidi A, Thille AW, Brochard L. Diaphragm ultrasonography to estimate the work of breathing during non-invasive ventilation. Intensive Care Med. 2012 May;38(5):796-803. doi: 10.1007/s00134-012-2547-7. Epub 2012 Apr 5. PMID: 22476448.\u003c/li\u003e\n \u003cli\u003eSchulz A, Erbuth A, Boyko M, Vonderbank S, G\u0026uuml;rleyen H, Gibis N, Bastian A. Comparison of Ultrasound Measurements for Diaphragmatic Mobility, Diaphragmatic Thickness, and Diaphragm Thickening Fraction with Each Other and with Lung Function in Patients with Chronic Obstructive Pulmonary Disease. Int J Chron Obstruct Pulmon Dis. 2022 Sep 12;17:2217-2227. doi: 10.2147/COPD.S375956. PMID: 36118281; PMCID: PMC9480595.\u003c/li\u003e\n \u003cli\u003eScott S, Fuld JP, Carter R, McEntegart M, MacFarlane NG. Diaphragm ultrasonography as an alternative to whole-body plethysmography in pulmonary function testing.\u0026nbsp;J Ultrasound Med 2006;25(2):225-32.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCardenas LZ, Santana PV, Caruso P, de Carvalho CRR, de Albuquerque ALP.\u0026nbsp;Diaphragmatic ultrasound correlates with inspiratory muscle strength and pulmonary function in healthy subjects,\u0026nbsp;Ultrasound Med Biol 2018;44:786-93.\u003c/li\u003e\n \u003cli\u003eRocha FR, Br\u0026uuml;ggemann AK, Francisco DS, Medeiros CS, Rosal D, Paulin E. Diaphragmatic mobility: relationship with lung function, respiratory muscle strength, dyspnea, and physical activity in daily life in patients with COPD, J Bras Pneumol 2017;43(1):32-7.\u003c/li\u003e\n \u003cli\u003eHua-Rong Z, Liang C, Rong L, Yi-Fan T, Dou-Zi S, Yue C, Zu-Lin L. Ultrasonographic evaluation of diaphragm function in patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis. Medicine (Baltimore). 2022 Dec 23;101(51):e32560. doi: 10.1097/MD.0000000000032560. PMID: 36595865; PMCID: PMC9794219.\u003c/li\u003e\n \u003cli\u003eAn TJ, Yoo YJ, Lim JU, Seo W, Park CK, Rhee CK, Yoon HK. Diaphragm ultrasound is an imaging biomarker that distinguishes exacerbation status from stable chronic obstructive pulmonary disease.\u0026nbsp;Int J Chron Obstruct Pulmon Dis 2022;4(17):3-12.\u003c/li\u003e\n \u003cli\u003eAgarwala P, Salzman SH. Six-Minute Walk Test: Clinical Role, Technique, Coding, and Reimbursement. Chest. 2020 Mar;157(3):603-611. doi: 10.1016/j.chest.2019.10.014. Epub 2019 Nov 2. PMID: 31689414; PMCID: PMC7609960.\u003c/li\u003e\n \u003cli\u003eYamaguti WPDS, Paulin E, Salge JM, Chammas MC, Cukier A, Carvalho CRFD.\u0026nbsp;Diaphragmatic dysfunction and mortality in patients with COPD. J Bras Pneumol 2009;35:1174-81.\u003c/li\u003e\n \u003cli\u003ePaulin E, Yamaguti WP, Chammas MC, Shibao S, Stelmach R, Cukier A, Carvalho CR. Influence of diaphragmatic mobility on exercise tolerance and dyspnea in patients with COPD. Respir Med. 2007 Oct;101(10):2113-8. doi: 10.1016/j.rmed.2007.05.024. Epub 2007 Jul 20. PMID: 17644365.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"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":"Diaphragm, Ultrasonography, COPD, Diaphragmatic mobility","lastPublishedDoi":"10.21203/rs.3.rs-3246132/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3246132/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDiaphragmatic mobility (DM) may be reduced in chronic obstructive pulmonary disease (COPD) patients, but little is known about whether this mobility correlates with functional parameters, exercise capacity, and indicators of disease severity.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjective:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo evaluate the DM of COPD patients and relate the findings with the distance achieved in the six-minute walk test (6MWT), forced expiratory volume in one second (FEV\u003csub\u003e1\u003c/sub\u003e) % of predicted, residual volume (RV) % of predicted, and dyspnea.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAn observational cohort study was conducted to analyze DM through ultrasound during breathing, at rest and during deep inspiration and expiration.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIt was included 49 COPD stable patients. There was a correlation between the DM measured between expiration and maximum inspiration with FEV\u003csub\u003e1\u003c/sub\u003e% of predicted (r = 0.36; p = 0.012), RV % of predicted (r = -0.42; p = 0.01), RV/Total Lung Capacity (TLC) (r = -0.61; p \u0026lt; 0.001), and distance reached in the 6MWT (r = 0.46; p = 0.001). In addition, patients with MRCm \u0026lt;2 had a greater DM than those with a score \u003cu\u003e\u0026gt;\u003c/u\u003e2 (mean difference 13.20 \u003cu\u003e+\u003c/u\u003e 4.6 mm; p = 0.0059), and patients with a BODE index \u003cu\u003e\u0026lt;\u003c/u\u003e4 presented greater mobility (61.95 mm) than patients with a BODE index \u0026gt;4 (47.89 mm) (mean difference 14.05 \u003cu\u003e+\u003c/u\u003e 5.3 mm; 95% CI 25.09 to 3.01 mm).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe results obtained suggest that DM is related to bronchial obstruction (FEV1), lung hyperinflation (RV and RV/TLC), exercise capacity, and the measurement of dyspnea, suggesting that it is an option for evaluating COPD patients.\u003c/p\u003e","manuscriptTitle":"Ultrasonography as a way of evaluating the diaphragm muscle in patients with chronic obstructive pulmonary disease.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-09-06 14:29:03","doi":"10.21203/rs.3.rs-3246132/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":"27ee08d4-cff9-4a42-a8a7-a93d6eb40eda","owner":[],"postedDate":"September 6th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-06-13T09:23:09+00:00","versionOfRecord":[],"versionCreatedAt":"2023-09-06 14:29:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3246132","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3246132","identity":"rs-3246132","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}