Saturation of Respiratory Strain During Robotic Hysterectomy in Obese Women with Endometrial Cancer

Saturation of Respiratory Strain During Robotic Hysterectomy in Obese Women with Endometrial Cancer | 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 Saturation of Respiratory Strain During Robotic Hysterectomy in Obese Women with Endometrial Cancer Edward R. KOST, Martin Goros, Paulina Ramirez, Devin B. Burroughs, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7201588/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Objective: To evaluate intraoperative ventilatory mechanics during robotic-assisted hysterectomy in obese women with endometrial cancer and introduce the concept of a physiologic “ceiling effect” in respiratory strain. Methods: We conducted a retrospective cohort study of 89 women with biopsy-confirmed endometrial cancer who underwent robotic-assisted total hysterectomy between 2011 and 2015. Intraoperative ventilatory parameters, including plateau airway pressure and static lung compliance, were recorded at five-minute intervals. Each patient’s peak plateau pressure was identified to calculate static compliance and estimate maximum ventilatory strain. Patients were stratified by body mass index (BMI), and ventilatory parameters were compared across BMI categories at baseline (post-induction, supine) and during steep Trendelenburg positioning with carbon dioxide pneumoperitoneum. Results: At baseline, increasing BMI was significantly associated with higher plateau airway pressure and lower static compliance. For example, plateau pressure increased from 18.6 ± 3.4 centimeters of water (cm H₂O) in patients with BMI less than 30 kilograms per square meter to 25.9 ± 3.3 cm H₂O in those with BMI greater than or equal to 50 (p < 0.001). However, following Trendelenburg positioning with pneumoperitoneum, peak plateau pressures converged across BMI categories, averaging 35.0 ± 3.3 cm H₂O (p = 0.167). Static compliance also converged across BMI strata, averaging 17.2 ± 4.2 milliliters per cm H₂O (p = 0.129). Pulmonary complications occurred in 4.5% of patients, with no cases of barotrauma or prolonged mechanical ventilation. Conclusions: Intraoperative ventilatory strain appears driven primarily by surgical positioning and pneumoperitoneum, rather than obesity alone. These findings support the feasibility and safety of robotic-assisted hysterectomy across a wide range of body mass index values and introduce the novel concept of a physiologic ceiling effect in ventilatory stress. Figures Figure 1 Figure 2 Introduction Minimally invasive surgery (MIS) is the standard of care for endometrial cancer (EC) [ 1 ]. Compared to laparotomy, both conventional laparoscopy and robotic-assisted laparoscopic surgery (RALS) offer substantial perioperative advantages, including reduced blood loss, shorter hospitalization, less postoperative pain, faster recovery, and comparable oncologic outcomes [ 2 – 5 ]. Among MIS techniques, RALS has become the preferred approach for obese patients with EC, who are at increased risk of surgical complications. Robotic systems provide enhanced dexterity, visualization, and ergonomics, facilitating complex pelvic procedures such as hysterectomy and lymphadenectomy in patients with high body mass index (BMI) or challenging anatomy. Multiple studies have demonstrated the benefits of RALS over traditional laparoscopy in obese EC patients. A meta-analysis of over 10,000 cases found significantly lower conversion rates to laparotomy, particularly in those with BMI ≥ 40 kg/m² [ 6 ]. Additional studies have reported reduced blood loss, shorter hospital stays, fewer complications, and similar cancer outcomes, in obese patients undergoing robotic hysterectomy, despite longer operative times [ 7 – 9 ]. Despite these advantages, RALS introduces anesthetic challenges due to the need for Trendelenburg positioning and pneumoperitoneum (T/p), both of which significantly impair respiratory mechanics. These factors elevate plateau airway pressures (Pplat), reduce static compliance (Cstat), and increase the risk of pulmonary complications such as atelectasis, transient hypoxemia, hypercapnia, and, rarely, barotrauma or ventilator-induced lung injury (VILI) [ 10 – 13 ]. Central obesity further compromises lung mechanics by reducing thoracic compliance, limiting functional residual capacity, and impairing oxygenation [ 13 – 16 ]. In this context, careful intraoperative monitoring of ventilatory parameters is essential to mitigate respiratory risk and optimize safety in obese patients undergoing robotic-assisted hysterectomy. This study evaluates the combined impact of obesity and T/p on intraoperative respiratory mechanics during robotic-assisted hysterectomy for endometrial cancer. Using five-minute interval sampling, we identified each patient’s peak Pplat to capture the moment of maximal ventilatory strain. During analysis, we observed a physiologic convergence, peak Pplat and Cstat values became statistically indistinguishable across BMI categories once T/p was established. This unanticipated finding suggests a saturation of respiratory strain, wherein the imposed mechanical load of surgical positioning and pneumoperitoneum exceeds the incremental impact of additional adiposity. This concept, described here as a "ceiling effect", emerges as a novel physiologic insight into ventilatory tolerance during robotic pelvic surgery. Materials and Methods Patient Selection This retrospective cohort study was approved by the Institutional Review Boards (IRBs) of the University of Texas Health San Antonio and the University Hospital System (UHS). We identified 89 consecutive women with histologically confirmed endometrial carcinoma who underwent robotic-assisted total hysterectomy with surgical staging between 2011 and 2015. Surgical Technique All procedures were performed using the da Vinci Si Surgical System (Intuitive Surgical, Sunnyvale, CA) by board-certified gynecologic oncologists with assistance from obstetrics and gynecology residents. Surgical staging included total hysterectomy, bilateral salpingo-oophorectomy, and pelvic and/or para-aortic lymph node assessment, based on clinicopathologic findings [17]. Ovarian preservation was considered in premenopausal women with early-stage disease, at the discretion of the surgeon [18]. Anesthesia Protocol and Intraoperative Management 1. Induction and Maintenance of Anesthesia General anesthesia was administered with endotracheal intubation following induction using midazolam, a short-acting opioid (typically fentanyl), and either propofol or etomidate. Neuromuscular blockade was achieved with rocuronium or succinylcholine. Maintenance anesthesia was provided using sevoflurane or desflurane, supplemented with intravenous opioids as needed. Anesthetic care was delivered by board-certified anesthesiologists with support from anesthesia residents and certified registered nurse anesthetists (CRNAs). 2. Physiologic Monitoring and Patient Positioning Intraoperative monitoring included electrocardiography, pulse oximetry, capnography, core temperature (via esophageal or bladder probes), and non-invasive blood pressure. In select high-risk patients, radial arterial catheters were placed for beat-to-beat blood pressure monitoring and arterial blood gas sampling. Patients were positioned in dorsal lithotomy and secured per institutional protocol. Steep Trendelenburg positioning (~30°) was used throughout robotic access, and carbon dioxide pneumoperitoneum was maintained at 15 mm Hg. 3. Intraoperative Ventilation Management Anesthetic ventilation practices reflected institutional lung-protective strategies used from 2011 to 2015 [19]. Volume-controlled ventilation mode (VCV) was used for the majority of patients based on provider preference. Tidal volumes were generally maintained at 6–8 mL/kg ideal body weight, with PEEP typically set at 5–8 cmH₂O. FiO₂ was titrated to maintain oxygen saturation >94%, and respiratory rate was adjusted to ensure normocarbia. Recruitment maneuvers were selectively applied in cases of worsening compliance or oxygenation. Compliance-adjusted PEEP titration and advanced ventilatory monitoring techniques such as esophageal pressure-guided ventilation or electrical impedance tomography were not in routine use at the time. Ventilation mode, VCV or pressure-controlled ventilation mode (PCV), was individualized, with VCV favored for stable tidal volume delivery and PCV occasionally employed to reduce peak airway pressures. Ventilator settings were adjusted based on dynamic airway pressures, oxygenation, and patient-specific physiology. 4. Ventilatory Parameter Monitoring and Interpretation Ventilatory parameters, including peak inspiratory pressure (PIP), tidal volume (TV), end-tidal CO₂, and dynamic compliance, were continuously displayed on the anesthesia workstation. PIP was evaluated at defined procedural checkpoints (e.g., post-intubation, post-insufflation, during Trendelenburg, and upon clinical changes). PIP served as a practical screening metric for changes in resistance or compliance, but its composite nature limited its diagnostic specificity. When compliance-related concerns were raised, Pplat was measured using an inspiratory pause maneuver (typically 0.5–1.0 seconds). Pplat offered a more accurate surrogate for alveolar pressure and was selectively measured to differentiate between increased resistance (e.g., bronchospasm, secretions) and reduced lung compliance (e.g., pneumoperitoneum, Trendelenburg effects). In this cohort, Pplat was used as a confirmatory value in cases of elevated PIP, unexplained desaturation, or concern for excessive ventilatory load. Most patients had one or two intraoperative Pplat measurements, in line with standard practice during the study period. Though advanced monitoring tools were not employed, careful interpretation of ventilatory parameters enabled effective management, even in patients with morbid obesity. Study Design 1. Overview and Data Collection This retrospective observational study analyzed ventilatory data and clinical outcomes in consecutive women undergoing robotic-assisted hysterectomy between 2011 and 2015. Demographic, surgical, anesthetic, and pathologic variables were abstracted post hoc from the electronic medical record (EMR). 2. Intraoperative Respiratory Data Acquisition During surgery respiratory mechanics were continuously recorded and automatically archived using the Servo-i ventilator system (Servo Screen 390 V2.0, Siemens-Elma AB). Data were retrospectively sampled from archived anesthetic records at standardized five-minute intervals. At each timepoint, values for PIP, Pplat, TV, respiratory rate, PEEP, and FiO₂ were reviewed. No real-time data were collected; all values were extracted retrospectively. Baseline respiratory measurements were obtained immediately following anesthesia induction with the patient in the supine position, after confirmation of hemodynamic stability. Subsequent measurements were recorded during the surgery with the patient in T/p, at 5-minute intervals. The peak Pplat was defined as the highest recorded Pplat during the surgery in T/p. 3. Peak Plateau Pressure as Anchor for Respiratory Analysis Each patient’s ventilatory dataset was reviewed to identify the five-minute interval with the highest Pplat. This peak Pplat timepoint served as the physiologic anchor for all respiratory analyses. Additional parameters captured at this interval were used to calculate Cstat, using the formula: Cstat = Tidal Volume (TV) / (Pplat – PEEP) All values were taken from the peak Pplat interval, ensuring a standardized, high-strain reference point for each patient. This method allowed for physiologic comparisons across a heterogeneous surgical cohort. 4. Justification for Five-Minute Pplat Sampling Strategy A five-minute retrospective sampling interval was selected to balance feasibility with physiologic resolution. Shorter intervals were impractical for retrospective review, while longer intervals risked missing transient but meaningful spikes in airway pressure. Thus, a five-minute sampling interval was selected as a feasible and physiologically informative compromise. Statistical Analysis Continuous variables were expressed as mean ± standard deviation (SD) or median and interquartile range (IQR), depending on distribution assessed via histograms, Q–Q plots, and the Shapiro–Wilk test. Categorical variables were reported as frequencies and percentages. One-way ANOVA was used to compare continuous variables across BMI categories. Post hoc pairwise comparisons were conducted as appropriate. The Wilcoxon signed-rank test was used for paired comparisons between baseline (post-intubation, supine) and during surgery in Trendelenburg position with pneumoperitoneum. Chi-square (χ²) or Fisher’s exact tests were used for categorical data. Linear regression was used to explore the relationship between BMI and respiratory mechanics (e.g., peak Pplat, Cstat) at baseline (post-intubation, supine) and during surgery in Trendelenburg position with pneumoperitoneum. Regression coefficients and 95% confidence intervals (CI) were reported. Given the exploratory nature and modest sample size, covariate adjustments (e.g., age, ASA class) and interaction terms (e.g., BMI × surgical time) were not included. No adjustments for multiple comparisons were applied to preserve statistical power. Missing data were minimal (<5%) and managed using complete case analysis. All p-values were two-tailed, with significance defined as p < 0.05. All statistical analyses were conducted using SPSS version 29.0 (IBM Corp., Armonk, NY). Results Patient Demographics, Tumor Characteristics, and Perioperative Metrics A total of 89 women underwent robotic-assisted hysterectomy for endometrial cancer and were included in this retrospective analysis. The mean BMI for the cohort was 37.5 ± 9.9 kg/m². Class III obesity (BMI ≥ 40 kg/m²) was observed in 40.4% of patients, with 10.1% classified as BMI ≥ 50 kg/m². Table 1 summarizes demographic, tumor, and perioperative characteristics stratified by BMI. Table 1 Demographic, Pathologic, and Perioperative Characteristics Stratified by Body Mass Index (BMI) Category Variable (unit) < 30 (n = 22) 30–34.9 (n = 15) 35–39.9 (n = 18) 40–44.9 (n = 16) 45–49.9 (n = 9) ≥ 50 (n = 9) Total (n = 89) P-value BMI (kg/m²) 25.6 ± 2.9 32.4 ± 1.5 37.2 ± 1.6 42.4 ± 1.7 47.4 ± 1.9 56.9 ± 4.9 37.5 ± 9.9 Age (years) 60.2 ± 11.7 60.7 ± 10.7 51.6 ± 14.3 54.4 ± 9.7 43.7 ± 14.0 47.1 ± 9.8 54.5 ± 12.9 0.002 Tumor Grade 1 7 (31.8%) 5 (33.3%) 13 (72.2%) 10 (62.5%) 7 (77.8%) 7 (77.8%) 49 (55.1%) Tumor Grade 2 7 (31.8%) 6 (40.0%) 4 (22.2%) 6 (37.5%) 2 (22.2%) 2 (22.2%) 27 (30.3%) Tumor Grade 3 8 (36.4%) 4 (26.7%) 1 (5.6%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 13 (14.6%) 0.013 Tumor Stage – I 14 (63.6%) 9 (60.0%) 17 (94.4%) 12 (75.0%) 9 (100.0%) 9 (100.0%) 70 (78.7%) Tumor Stage – II 2 (9.1%) 4 (26.7%) 1 (5.6%) 1 (6.2%) 0 (0.0%) 0 (0.0%) 8 (9.0%) Tumor Stage – III 6 (27.3%) 2 (13.3%) 0 (0.0%) 3 (18.8%) 0 (0.0%) 0 (0.0%) 11 (12.4%) 0.039 Histology – Low Risk 17 (77.3%) 13 (86.7%) 18 (100.0%) 16 (100.0%) 9 (100.0%) 9 (100.0%) 82 (97.8%) Histology – High Risk 5 (22.7%) 2 (13.3%) 0 (0.0%) 0 (0.0%) 0 0 (0.0%) 7 (2.2%) 0.033 LN Procedure – None 9 (40.9%) 5 (33.3%) 11 (61.1%) 7 (43.8%) 8 (88.9%) 7 (77.8%) 47 (52.8%) LN Procedure – Pelvic Only 6 (27.3%) 4 (26.7%) 4 (22.2%) 5 (31.2%) 1 (11.1%) 0 (0.0%) 20 (22.5%) LN Procedure – Pelvic + Para-aortic 7 (31.8%) 6 (40.0%) 3 (16.7%) 4 (25.0%) 0 (0.0%) 2 (22.2%) 22 (24.7%) 0.200 Pelvic LN Count 21.2 ± 9.0 22.6 ± 13.1 23.3 ± 5.1 26.9 ± 8.0 42.0 48.5 ± 36.1 25.0 ± 12.3 0.039 Para-aortic LN Count 8.3 ± 6.8 8.7 ± 3.9 12.3 ± 6.7 10.3 ± 3.6 N = 0 12.0 ± 4.2 9.6 ± 5.1 0.769 Uterine Weight (g) 153.9 ± 89.4 144.4 ± 107.8 160.4 ± 90.7 168.8 ± 94.1 128.7 ± 59.9 180.2 ± 75.4 156.4 ± 88.9 0.835 Estimated Blood Loss (mL) 143.0 ± 115.8 109.7 ± 65.8 182.5 ± 207.0 218.4 ± 232.4 165.0 ± 147.4 155.6 ± 72.6 162.4 ± 158.3 0.515 Length of Stay (hrs) 45.4 ± 17.6 51.9 ± 28.0 59.0 ± 69.5 47.9 ± 62.3 51.6 ± 28.4 52.1 ± 23.5 51.0 ± 43.6 0.620 Any Complication 3 (13.6%) 3 (20.0%) 7 (38.9%) 4 (25.0%) 1 (11.1%) 2 (22.2%) 20 (22.5%) 0.649 IOC 1 (4.5%) 0 (0.0%) 1 (5.6%) 1 (6.2%) 0 (0.0%) 0 (0.0%) 3 (3.4%) 0.861 POC 0 (0.0%) 2 (13.3%) 4 (22.2%) 2 (12.5%) 1 (11.1%) 2 (22.2%) 11 (12.4%) 0.352 Transfusion 2 (9.1%) 1 (6.7%) 2 (11.1%) 1 (6.2%) 0 (0.0%) 0 (0.0%) 6 (6.7%) 0.843 Urgent Care or ER Visit ≥ 1 6 (27.3%) 2 (13.3%) 5 (27.8%) 4 (25.0%) 3 (33.3%) 2 (22.2%) 22 (24.7%) 0.53 Data are presented as mean ± standard deviation (SD) for continuous variables and as number (percentage) for categorical variables. BMI = Body Mass Index (kg/m²); LN = Lymph Node; IOC = Intraoperative Complication; POC = Postoperative Complication. P-values were calculated using one-way ANOVA for continuous variables and chi-square or Fisher’s exact test for categorical variables. Bolded P-values indicate statistical significance (P < 0.05). Patient age varied significantly by BMI category, with younger patients more commonly represented in the higher BMI groups (p = 0.002). Tumor biology also differed across BMI strata. Grade 1 (low-grade) tumors were more prevalent in higher BMI categories (p = 0.013), while Grade 3 tumors were restricted to patients with BMI < 40 kg/m². Similarly, Stage I disease predominated in higher BMI groups (p = 0.039), whereas Stage III disease was seen exclusively in patients with BMI < 45. High-risk histologic subtypes were rare (7 of 89 patients, 2.2%), occurring only in the lowest and mid-range BMI groups (p = 0.033). Lymphadenectomy was performed in 47.2% of patients, without significant variation in lymph node procedure type (pelvic and para-aortic) across BMI categories (p = 0.200). However, pelvic lymph node yield increased significantly with increasing BMI (p = 0.039), while para-aortic node counts did not (p = 0.769). Uterine weight, estimated blood loss, and length of hospital stay were not significantly associated with BMI (p = 0.835, p = 0.515, and p = 0.620, respectively). A total of 20 (22.5%) patients had any complications including intraoperative (3.4%), postoperative (12.4%), and blood transfusion (6.7%). However, the rates of complications did not differ by BMI group, Table 1 . Specific complication data is presented in Table 2 . Pulmonary complications were seen in 4 patients (4.5%). Two patients required delayed extubation or reintubation, while one developed postoperative pneumonia and another experienced a pulmonary embolism. No patients suffered barotrauma or required prolonged mechanical ventilation (> 24 hours). Only one case (1.1%) required conversion to laparotomy, performed to address a vascular injury unrelated to respiratory mechanics. For transparency, we included all complications in our totals including minor complications consisting of 4 cases of trocar site infections (wound infections) and 3 cases of postoperative slow return of bowel function (ileus). Table 2 Perioperative Complications Among Patients Undergoing Robotic-Assisted Hysterectomy Complication Pulmonary complications 4 (4.5%) Delayed extubation or reintubation 2 Pneumonia 1 Pulmonary embolism 1 All-cause complications 10 (11.2%) Conversion to laparotomy 1 Vascular injury 1 Ureteral injury 1 Wound infection 4 Postoperative ileus 3 Transfusion 6 (6.7%) Total patients with any complication 20 (22.5%) Complications are presented as number (percentage) of the total cohort (N = 89). Pulmonary complications include delayed extubation, pneumonia, pulmonary embolism, and reintubation. One conversion to laparotomy occurred for vascular repair. No cases of barotrauma or ventilator-induced lung injury (VILI) were observed. Intraoperative Anesthesia Parameters and Respiratory Mechanics Table 3 details intraoperative ventilatory and anesthetic characteristics by BMI. ASA classification did not differ significantly with BMI (p = 0.496), with 77.5% of patients classified as ASA Class 3. Arterial line placement increased significantly with BMI (p = 0.020), from 59.1% in patients with BMI < 30 to 100% in those with BMI 45–49.9, reflecting greater perceived anesthetic complexity in higher BMI patients. Table 3 Anesthesia and Intraoperative Respiratory Mechanics Stratified by Body Mass Index (BMI) Category Variable < 30 (n = 22) 30–34.9 (n = 15) 35–39.9 (n = 18) 40–44.9 (n = 16) 45–49.9 (n = 9) ≥ 50 (n = 9) Total (n = 89) P-value ASA 2 4 (18.0%) 4 (27.0%) 3 (17.0%) 0 (0.0%) 1 (11.0%) 0 (0.0%) 12 (13.5%) 0.496 ASA 3 17 (77.0%) 10 (67.0%) 14 (78.0%) 14 (88.0%) 6 (67.0%) 8 (89.0%) 69 (77.5%) ASA 4 1 (5.0%) 1 (7.0%) 1 (6.0%) 2 (12.0%) 2 (22.0%) 1 (11.0%) 8 (9.0%) Arterial Line 13 (59.1%) 9 (60.0%) 15 (83.3%) 14 (87.5%) 9 (100.0%) 8 (88.9%) 69 (77.5%) 0.020* PIP (Baseline) 20.2 ± 4.3 23.1 ± 3.3 24.5 ± 3.8 25.6 ± 3.1 27.1 ± 2.8 29.6 ± 4.2 24.3 ± 4.6 < 0.001* PIP, peak (T/p) 38.1 ± 3.1 40.2 ± 2.3 39.9 ± 2.0 40.8 ± 6.8 40.9 ± 3.9 41.7 ± 3.2 40.0 ± 4.0 0.198 Pplat (Baseline) 18.6 ± 3.4 20.6 ± 2.4 21.5 ± 3.5 22.9 ± 3.1 23.9 ± 4.3 25.9 ± 3.3 21.7 ± 3.9 < 0.001* Pplat, peak (T/p) 33.6 ± 3.1 35.9 ± 2.6 35.9 ± 2.1 34.0 ± 3.9 36.0 ± 4.2 34.8 ± 3.7 35.0 ± 3.3 0.167 Cstat (Baseline) 39.4 ± 8.6 33.0 ± 4.9 36.4 ± 6.0 33.2 ± 5.8 31.4 ± 7.4 29.4 ± 4.4 34.6 ± 7.1 0.002* Cstat, peak (T/p) 17.4 ± 3.1 15.4 ± 2.9 18.3 ± 4.2 18.9 ± 5.5 15.0 ± 4.0 16.7 ± 5.1 17.2 ± 4.2 0.129 P/F Ratio (T/p) 355.1 ± 108.8 327.9 ± 95.9 276.6 ± 110.0 288.2 ± 97.8 246.8 ± 99.7 262.2 ± 125.2 294.8 ± 109.1 0.214 Operative Time (min) 259.7 ± 71.1 246.7 ± 73.8 235.5 ± 85.7 260.1 ± 72.1 329.6 ± 338.1 251.3 ± 57.3 258.9 ± 125.4 0.610 Anesthesia Time (min) 344.4 ± 85.0 330.7 ± 72.1 341.8 ± 114.8 359.8 ± 71.2 330.4 ± 68.4 362.3 ± 62.8 344.9 ± 83.0 0.905 In room to cut, TTSS (min) 59.7 ± 15.1 60.8 ± 13.6 62.5 ± 12.3 66.7 ± 18.3 72.8 ± 11.9 73.6 ± 14.4 64.6 ± 15.0 0.085 Values are presented as mean ± standard deviation (SD) for continuous variables or number (percentage) for categorical variables. Comparisons across BMI categories were performed using one-way ANOVA for continuous variables and chi-square or Fisher’s exact test for categorical variables. PIP = Peak Inspiratory Pressure; Pplat = Plateau Pressure; Cstat = Static Lung Compliance; P/F Ratio = Arterial oxygen partial pressure to fractional inspired oxygen ratio (PaO₂/FiO₂); T/p = Trendelenburg positioning with pneumoperitoneum; TTSS = Time from operating room entry to surgical start; ASA = American Society of Anesthesiologists Physical Status Classification. P-values < 0.05 were considered statistically significant. At baseline (intubated, supine, pre-insufflation), respiratory mechanics were significantly affected by BMI. Peak inspiratory pressure (PIP) increased from 20.2 ± 4.3 cmH₂O in the lowest BMI group to 29.6 ± 4.2 cmH₂O in those with BMI ≥ 50 (p < 0.001). Baseline Pplat similarly rose with increasing BMI (p < 0.001), increasing from 18.6 ± 3.4 to 25.9 ± 3.3 cmH₂O. Static compliance (Cstat) decreased significantly from 39.4 ± 8.6 to 29.4 ± 4.4 mL/cmH₂O across the BMI range (p = 0.002). However, during T/p these BMI differences diminished. Peak PIP during T/p averaged 40.0 ± 4.0 cmH₂O and did not differ significantly across BMI categories (p = 0.198). Similarly, peak Pplat reached a cohort mean of 35.0 cmH₂O and was statistically indistinguishable between BMI groups (p = 0.167). Cstat values during T/p ranged from 17.4 ± 3.1 to 16.7 ± 5.1 mL/cmH₂O and did not differ significantly across BMI categories (p = 0.129). The arterial oxygen partial pressure (PaO₂) to fractional inspired oxygen (FiO₂), (P/F ratio), during T/p showed a non-significant downward trend with increasing BMI (p = 0.214), with the lowest average observed in the BMI 45–49.9 group (246.8 ± 99.7). Operative time, anesthesia duration, and in-room-to-incision time (TTSS) were similar across BMI groups (p = 0.610, p = 0.905, and p = 0.085, respectively), although TTSS tended to be longer in patients with higher BMI. Changes in Respiratory Mechanics with T/p Figure 1 illustrates the changes in peak Pplat and Cstat moving from baseline (intubated, supine position) to surgery in T/p. Median peak Pplat increased from 22.0 cmH₂O to 33.0 cmH₂O (p < 0.001), and median Cstat decreased from 33.3 to 16.7 mL/cmH₂O (p < 0.001), highlighting the pronounced effect of T/p on respiratory mechanics across all BMI categories. Figure 2 presents the association between BMI and respiratory mechanics. At baseline, BMI was significantly associated with higher peak Pplat (β = 0.29 cmH₂O per kg/m²; 95% CI, 0.14–0.45; p < 0.001) and lower Cstat (β = − 0.91 mL/cmH₂O per kg/m²; 95% CI, − 1.26 to − 0.57; p < 0.001). In contrast, no significant associations were seen between BMI and peak Pplat (p = 0.32) or Cstat (p = 0.663) during T/p, suggesting a physiologic convergence or saturation point in respiratory mechanics. Discussion Key Findings In this retrospective study of 89 women undergoing robotic-assisted hysterectomy for endometrial cancer, we found that surgery in T/p exerted the most significant influence on intraoperative respiratory mechanics, surpassing the effects of baseline obesity. While increased airway pressures and reduced lung compliance was associated with obesity at baseline, these differences were modest compared to the pronounced and uniform changes induced by T/p. Once insufflation and positioning were established, plateau pressures and static compliance values converged across BMI groups, highlighting the dominant role of surgical conditions in determining peak ventilatory strain. Comparison to Existing Literature Our findings align with prior reports demonstrating favorable perioperative outcomes in obese women undergoing robotic-assisted hysterectomy for endometrial cancer [ 6 – 9 ]. In our cohort, the pulmonary complication rate was 4.5%, comparable to prior studies reporting rates below 5% in similar populations. For example, Wysham et al. reported a 3.0% complication rate in a multicenter analysis of 1,089 patients with age, but not BMI, identified as the primary predictor of pulmonary morbidity [ 20 ]. Similarly, Burke et al. found no association between BMI and postoperative respiratory outcomes, despite elevated intraoperative airway pressures in obese patients [ 21 ]. Eddib et al. also reported a low complication rate in obese women undergoing robotic hysterectomy, reinforcing the safety of this approach across BMI strata [ 22 ]. Collectively, our study and the above findings support the feasibility and safety of robotic surgery in high-BMI populations when modern anesthetic and lung-protective strategies are employed [ 23 ]. We observed that increasing BMI correlates with impaired baseline respiratory mechanics, i.e. before insufflation and Trendelenburg positioning. Specifically, patients with BMI ≥ 50 mg/m2 exhibited significantly higher baseline Pplat and lower Cstat compared to patients with BMI < 30 mg/m2. These findings align with the restrictive ventilatory physiology of obesity, characterized by reduced thoracic compliance, increased intra-abdominal pressure, and diminished diaphragmatic excursion, leading to decreased functional residual capacity and a predisposition to atelectasis even before surgical intervention. Our observations are supported by previous studies that have documented similar impairments in respiratory mechanics among obese individuals [ 13 – 16 , 24 – 26 ]. Our findings align with prior studies demonstrating that T/p increases Pplat and decreases Cstat compared to the non-insufflated, supine position [ 10 , 13 , 14 , 24 – 28 ]. However, unlike our results, several earlier investigations continued to report a linear or additive effect of increasing BMI on ventilatory strain even after T/p was established [ 13 , 24 , 26 ]. This discrepancy may reflect key differences in data sampling strategies. Prior studies such as those by Tomescu et al. [ 26 ] and Tharp et al. [ 24 ] collected ventilatory parameters at standardized intraoperative time points, typically post-induction, post-insufflation, mid-procedure, and end-of-case, regardless of what was occurring physiologically at those times. Similarly, Sprung et al. [ 13 ] measured changes in pulmonary mechanics during pneumoperitoneum in laparoscopic surgery but did not dynamically track physiologic peaks. These fixed-time methods, while convenient, likely missed transient but clinically meaningful spikes in ventilatory pressure that occur during discrete surgical events. As a result, the plateau pressures they reported, typically 25–32 cm H₂O, may underestimate the true peak mechanical stress, leading to continued identification of a linear relationship between Pplat and BMI. In contrast to prior studies, our methodology employed systematic five-minute interval sampling, allowing precise identification of individualized peak Pplat values across the cohort. This approach revealed consistent peak Pplat measurements of 35–36 cm H₂O, confirming that our sampling strategy effectively captured transient periods of maximal mechanical load on the respiratory system. These Pplat peaks likely corresponded to specific intraoperative events—such as trocar manipulation, specimen extraction, transient elevations in pneumoperitoneum pressure, and uterine manipulation—that acutely increased intra-abdominal pressure. When superimposed on the baseline strain induced by T/p, these transient factors produced abrupt elevations in diaphragmatic load, thereby increasing Pplat. This study introduces the concept of a physiologic “ceiling effect” in intraoperative respiratory mechanics during robotic-assisted hysterectomy in obese women. As shown in Fig. 2, once T/p was established, Pplat values converged across all BMI categories, stabilizing at approximately 35–36 cm H₂O. There was no statistically significant difference in peak Pplat among patients with BMI < 30, 30–39.9, 40–49.9, and ≥ 50 (p = NS), suggesting a saturation point beyond which further increases in BMI did not impose additional ventilatory strain. This implies that the combination of T/p and transient surgical events generates a maximal diaphragmatic load, after which additional adiposity has minimal incremental impact on thoracic compliance or diaphragmatic excursion. The resulting “ceiling effect” offers a novel framework for understanding ventilatory mechanics in obese patients and supports the feasibility of robotic hysterectomy across a broad BMI spectrum, particularly with lung-protective ventilation strategies. Clinical and Scientific Implications and Future Research Our findings challenge the assumption that BMI is a reliable predictor of intraoperative ventilatory burden. Once T/p was established, Pplat and Cstat converged across BMI categories, indicating that surgical positioning and insufflation—not adiposity alone—drive intraoperative respiratory load. Future studies should explore alternative physiologic phenotyping approaches that consider central adiposity, abdominal compliance, and thoracic geometry. While Pplat and Cstat were our primary variables, we did not consistently capture driving pressure (ΔP = Pplat - PEEP) or mechanical power, both of which may better reflect the true mechanical forces acting on lung tissue. These parameters have shown promise in predicting ventilator-induced lung injury in critical care and intraoperative settings [ 29 – 31 ]. Prospective studies using continuous monitoring of ΔP and mechanical power could refine real-time assessments of ventilatory strain and inform anesthetic decision-making in high-risk patients. We propose the term "Surgical Lung Stress Load" (SLSL) to describe the cumulative physiologic burden imposed by T/p, operative manipulation, and procedural duration on respiratory mechanics. Conceptually, SLSL parallels the critical care concept of mechanical power, representing the total energy applied to the lung—but with emphasis on procedure-specific mechanical strain. Our data suggest that SLSL, not BMI, may be the dominant determinant of ventilatory strain. Quantifying SLSL in future studies may facilitate personalized ventilation strategies and advance risk stratification frameworks for minimally invasive surgery. As a hypothetical example, an anesthesiologist monitoring intraoperative Pplat and ΔP in a patient with BMI ≥ 50 might observe stable parameters following the onset of T/p, despite a temporary rise in Pplat to 35 cmH₂O. Understanding that this may reflect a ceiling state rather than progressive stress could help avoid unnecessary recruitment maneuvers, adjustments in Trendelenburg angle, or decreases in pneumoperitoneum pressure, especially in the absence of hypoxemia or hemodynamic instability. Strengths This study offers several strengths. It is one of the few to examine intraoperative respiratory mechanics in a homogeneous cohort of obese women undergoing robotic-assisted hysterectomy, including a substantial proportion with class III and super obesity. Our use of individualized peak Pplat during T/p provides a physiologically grounded approach that reflects actual patient-specific stress points rather than arbitrary time intervals. This novel methodology allows for more accurate assessment of intrathoracic load and highlights transient but potentially important pressure elevations that may be missed with static sampling. Finally, the absence of adverse pulmonary events despite frequent peak Pplat > 35 cmH₂O reinforces the safety of robotic-assisted surgery in obese women when lung-protective strategies are employed. Limitations While the proposed ceiling effect offers a meaningful physiologic insight, several intraoperative and anesthesia-related limitations must be considered when interpreting these findings. First, we lacked intraoperative time-stamped data linking peak Pplat measurements to specific surgical or anesthetic events. This limits the ability to draw causal inferences. For example, anesthetic factors, including coughing, incomplete paralysis, ventilator-patient dyssynchrony, may also have contributed to peaks in pressure recordings. Second, anesthetic management was not standardized across the cohort. Differences in providers, ventilator settings, levels of PEEP, and use of recruitment maneuvers introduce variability that could influence both airway pressures and lung compliance. Third, important respiratory metrics—such as minute ventilation, end-tidal carbon dioxide (EtCO₂), and arterial carbon dioxide (PaCO₂)—were not consistently available for study analysis. This limits our ability to assess ventilation adequacy or detect hypercapnia, especially in prolonged cases or those involving super obesity. Although no episodes of sustained hypoxemia were reported, reliance on intermittent arterial oxygen measurements (PaO₂) may have missed transient desaturation events. These are more common in obese patients under steep Trendelenburg with pneumoperitoneum due to reduced functional residual capacity and a predisposition to atelectasis. Moreover, the frequent use of high inspired oxygen fractions (FiO₂) may have masked early ventilation-perfusion mismatch or recruitment deficits. Conclusion This study offers a novel physiologic perspective on intraoperative respiratory mechanics in obese women undergoing robotic-assisted hysterectomy. By employing individualized five-minute interval sampling, we identified a consistent convergence of plateau airway pressures across body mass index (BMI) categories once steep Trendelenburg positioning and carbon dioxide pneumoperitoneum were established. This pattern—termed the “ceiling effect”—suggests that surgical conditions, rather than obesity alone, are the dominant determinants of peak ventilatory strain. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress. These findings challenge conventional assumptions about the linear relationship between BMI and intraoperative respiratory burden. Importantly, they offer clinically actionable insights: once maximal mechanical load is imposed by positioning and insufflation, further adjustments to ventilation or intra-abdominal pressure may be unnecessary in hemodynamically stable patients—even those with super obesity. This could inform more nuanced and efficient anesthetic management strategies during robotic pelvic surgery. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress. While this retrospective study does not establish definitive clinical thresholds, it provides a physiologically grounded, hypothesis-generating framework for future research. Prospective studies using standardized anesthetic protocols, continuous waveform analysis, and real-time tracking of driving pressure and mechanical power are needed to validate these findings and explore the concept of surgical lung stress load as a practical tool for intraoperative risk assessment. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress. In summary, the recognition of a ceiling effect in respiratory strain advances our understanding of ventilatory physiology during robotic-assisted surgery and supports the safe, tailored application of minimally invasive approaches in obese surgical populations. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress. Declarations Acknowledgments The authors would like to thank the Department of Anesthesiology and the Department of Obstetrics and Gynecology at the University of Texas Health San Antonio for their collaboration and support. We also acknowledge the University Hospital System IRB for data access and ethical review. Special thanks to the anesthesia providers and surgical residents whose clinical care enabled this retrospective analysis. Conflict of Interest and Funding Disclosures The authors declare no conflicts of interest related to this study. No external funding was received for this work. Ethics Approval Statement This study was approved by the Institutional Review Board (IRB) of the University of Texas Health Science Center at San Antonio (Protocol #HSC20150511H). The requirement for informed consent was waived due to the retrospective nature of the study. Author Contribution E. K.: Conceptualization, study design, supervision, data interpretation, manuscript drafting, and critical revision. M. G.: Statistical analysis, data interpretation, and manuscript editing. J.G.: Statistical oversight, methodological guidance, and manuscript review. D. B.: Clinical interpretation of anesthetic data, manuscript review, and technical guidance on ventilatory parameters. G. M., P.R.: Study coordination, clinical validation, manuscript drafting, and critical manuscript revision. E.K., M.G., P.R., D.B., J.G., G.M.: made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work; drafted the work or revised it critically for important intellectual content; approved the 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. References National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Uterine Neoplasms. Version 3.2025 — March 7, 2025. Walker JL, Piedmonte MR, Spirtos NM, Eisenkop SM, Schlaerth JB, Mannel RS, Spiegel G, Barakat R, Pearl ML, Sharma SK. Laparoscopy compared with laparotomy for comprehensive surgical staging of uterine cancer: Gynecologic Oncology Group Study LAP2. J Clin Oncol. 2009;27(32):5331–6. doi: 10.1200/JCO.2009.22.3248. Epub 2009 Oct 5. PMID: 19805679; PMCID: PMC2773219. Walker JL, Piedmonte MR, Spirtos NM, Eisenkop SM, Schlaerth JB, Mannel RS, Barakat R, Pearl ML, Sharma SK. Recurrence and survival after random assignment to laparoscopy versus laparotomy for comprehensive surgical staging of uterine cancer: Gynecologic Oncology Group LAP2 Study. J Clin Oncol. 2012;30(7):695–700. doi: 10.1200/JCO.2011.38.8645. Epub 2012 Jan 30. Erratum in: J Clin Oncol. 2012;30(13):1570. PMID: 22291074; PMCID: PMC3295548. Kornblith AB, Huang HQ, Walker JL, Spirtos NM, Rotmensch J, Cella D. Quality of life of patients with endometrial cancer undergoing laparoscopic international federation of gynecology and obstetrics staging compared with laparotomy: a Gynecologic Oncology Group study. J Clin Oncol. 2009;27(32):5337-42. doi: 10.1200/JCO.2009.22.3529. Epub 2009 Oct 5. Erratum in: J Clin Oncol. 2010;28(16):2805. PMID: 19805678; PMCID: PMC2773220. Lindfors A, Heshar H, Adok C, Sundfeldt K, Dahm-Kähler P. Long-term survival in obese patients after robotic or open surgery for endometrial cancer. Gynecol Oncol. 2020;158(3):673–680. doi: 10.1016/j.ygyno.2020.05.684 . Epub 2020 Jun 9. PMID: 32527569. Cusimano MC, Simpson AN, Dossa F, Liani V, Kaur Y, Acuna SA, Robertson D, Satkunaratnam A, Bernardini MQ, Ferguson SE, Baxter NN. Laparoscopic and robotic hysterectomy in endometrial cancer patients with obesity: a systematic review and meta-analysis of conversions and complications. Am J Obstet Gynecol. 2019;221(5):410–428.e19. doi: 10.1016/j.ajog.2019.05.004. Epub 2019 May 10. PMID: 31082383. Yoshida K, Kondo E, Nimura R, Maki S, Kaneda M, Nii M, Ikeda T. Laparoscopic Versus Robotic Hysterectomy in Obese Patients With Early-stage Endometrial Cancer: A Single-centre Analysis. Anticancer Res. 2021;41(8):4163–4167. doi: 10.21873/anticanres.15220 . PMID: 34281888. Corrado G, Vizza E, Cela V, Mereu L, Bogliolo S, Legge F, Ciccarone F, Mancini E, Gallotta V, Baiocco E, Monterossi G, Perri MT, Zampa A, Pasciuto T, Scambia G. Laparoscopic versus robotic hysterectomy in obese and extremely obese patients with endometrial cancer: A multi-institutional analysis. Eur J Surg Oncol. 2018;44(12):1935–1941. doi: 10.1016/j.ejso.2018.08.021. Epub 2018 Sep 15. PMID: 30245146. Lechartier C, Bernard J, Renaud MC, Plante M. Robotic-assisted surgery for endometrial cancer is safe in morbidly and extremely morbidly obese patients. Gynecol Oncol. 2023;172:15–20. doi: 10.1016/j.ygyno.2023.02.014 . Epub 2023 Mar 9. PMID: 36905768. Suh MK, Seong KW, Jung SH, Kim SS. The effect of pneumoperitoneum and Trendelenburg position on respiratory mechanics during pelviscopic surgery. Korean J Anesthesiol. 2010;59(5):329–34. doi: 10.4097/kjae.2010.59.5.329 . Epub 2010 Nov 25. PMID: 21179295; PMCID: PMC2998653. Slutsky AS, Ranieri VM. Ventilator-induced lung injury. N Engl J Med. 2013;369(22):2126-36. doi: 10.1056/NEJMra1208707. Erratum in: N Engl J Med. 2014;370(17):1668-9. PMID: 24283226. Gattinoni L, Protti A, Caironi P, Carlesso E. Ventilator-induced lung injury: the anatomical and physiological framework. Crit Care Med. 2010;38(10 Suppl):S539-48. doi: 10.1097/CCM.0b013e3181f1fcf7 . PMID: 21164395. Sprung J, Whalley DG, Falcone T, Warner DO, Hubmayr RD, Hammel J. The impact of morbid obesity, pneumoperitoneum, and posture on respiratory system mechanics and oxygenation during laparoscopy. Anesth Analg. 2002;94(5):1345-50. doi: 10.1097/00000539-200205000-00056 . PMID: 11973218. Sprung J, Whalley DG, Falcone T, Wilks W, Navratil JE, Bourke DL. The effects of tidal volume and respiratory rate on oxygenation and respiratory mechanics during laparoscopy in morbidly obese patients. Anesth Analg. 2003;97(1):268 – 74, table of contents. doi: 10.1213/01.ane.0000067409.33495.1f . PMID: 12818980. Pelosi P, Croci M, Ravagnan I, Tredici S, Pedoto A, Lissoni A, Gattinoni L. The effects of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia. Anesth Analg. 1998;87(3):654 – 60. doi: 10.1097/00000539-199809000-00031 . PMID: 9728848. Pelosi P, Gregoretti C. Perioperative management of obese patients. Best Pract Res Clin Anaesthesiol. 2010;24(2):211 – 25. doi: 10.1016/j.bpa.2010.02.001. PMID: 20608558. Mariani A, Webb MJ, Keeney GL, Haddock MG, Calori G, Podratz KC. Low-risk corpus cancer: is lymphadenectomy or radiotherapy necessary? Am J Obstet Gynecol. 2000;182(6):1506-19. doi: 10.1067/mob.2000.107335 . PMID: 10871473. Wright JD, Buck AM, Shah M, Burke WM, Schiff PB, Herzog TJ. Safety of ovarian preservation in premenopausal women with endometrial cancer. J Clin Oncol. 2009;27(8):1214–9. doi: 10.1200/JCO.2008.19.8150 . Epub 2009 Jan 26. PMID: 19171707. Güldner A, Kiss T, Serpa Neto A, Hemmes SN, Canet J, Spieth PM, Rocco PR, Schultz MJ, Pelosi P, Gama de Abreu M. Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers. Anesthesiology. 2015;123(3):692–713. doi: 10.1097/ALN.0000000000000754 . PMID: 26120769. Wysham WZ, Kim KH, Roberts JM, Sullivan SA, Campbell SB, Roque DR, Moore DT, Gehrig PA, Boggess JF, Soper JT, Huh WK. Obesity and perioperative pulmonary complications in robotic gynecologic surgery. Am J Obstet Gynecol. 2015;213(1):33.e1-33.e7. doi: 10.1016/j.ajog.2015.01.033. Epub 2015 Jan 28. PMID: 25637843. Burks C, Nelson L, Kumar D, Fogg L, Saha C, Guirguis A, Rotmensch J, Dewdney S. Evaluation of Pulmonary Complications in Robotic-Assisted Gynecologic Surgery. J Minim Invasive Gynecol. 2017;24(2):280–285. doi: 10.1016/j.jmig.2016.11.001. Epub 2016 Nov 9. PMID: 27836798. Eddib A, Danakas A, Hughes S, Erk M, Michalik C, Narayanan MS, Krovi V, Singhal P. Influence of Morbid Obesity on Surgical Outcomes in Robotic-Assisted Gynecologic Surgery. J Gynecol Surg. 2014;30(2):81–86. doi: 10.1089/gyn.2012.0142 . PMID: 24803837; PMCID: PMC3995296. Song Z, Sun L, Chen P, Yu Y. Lung-protective ventilation strategy to improve oxygenation function and respiratory mechanics in patients undergoing robotic bariatric surgery: A randomized double-blind trial (CONSORT). Medicine (Baltimore). 2025;104(6):e41433. doi: 10.1097/MD.0000000000041433. PMID: 39928832; PMCID: PMC11813022. Tharp WG, Murphy S, Breidenstein MW, Love C, Booms A, Rafferty MN, Friend AF, Perrapato S, Ahern TP, Dixon AE, Bates JHT, Bender SP. Body Habitus and Dynamic Surgical Conditions Independently Impair Pulmonary Mechanics during Robotic-assisted Laparoscopic Surgery. Anesthesiology. 2020;133(4):750–763. doi: 10.1097/ALN.0000000000003442 . PMID: 32675698. Blecha S, Harth M, Zeman F, Seyfried T, Lubnow M, Burger M, Denzinger S, Pawlik MT. The impact of obesity on pulmonary deterioration in patients undergoing robotic-assisted laparoscopic prostatectomy. J Clin Monit Comput. 2019;33(1):133–143. doi: 10.1007/s10877-018-0142-3 . Epub 2018 Apr 16. PMID: 29663179. Tomescu DR, Popescu M, Dima SO, Bacalbașa N, Bubenek-Turconi Ș. Obesity is associated with decreased lung compliance and hypercapnia during robotic assisted surgery. J Clin Monit Comput. 2017;31(1):85–92. doi: 10.1007/s10877-016-9831-y . Epub 2016 Jan 28. PMID: 26823286; PMCID: PMC5253149. Rauh R, Hemmerling TM, Rist M, Jacobi KE. Influence of pneumoperitoneum and patient positioning on respiratory system compliance. J Clin Anesth. 2001;13(5):361-5. doi: 10.1016/s0952-8180(01)00286-0 . PMID: 11498317. Kalmar AF, Foubert L, Hendrickx JF, Mottrie A, Absalom A, Mortier EP, Struys MM. Influence of steep Trendelenburg position and CO(2) pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy. Br J Anaesth. 2010;104(4):433–9. doi: 10.1093/bja/aeq018 . Epub 2010 Feb 18. PMID: 20167583. Amato MB, Meade MO, Slutsky AS, Brochard L, Costa EL, Schoenfeld DA, Stewart TE, Briel M, Talmor D, Mercat A, Richard JC, Carvalho CR, Brower RG. Driving pressure and survival in the acute respiratory distress syndrome. N Engl J Med. 2015;372(8):747 – 55. doi: 10.1056/NEJMsa1410639 . PMID: 25693014. Gattinoni L, Tonetti T, Quintel M. Intensive care medicine in 2050: ventilator-induced lung injury. Intensive Care Med. 2018;44(1):76–78. doi: 10.1007/s00134-017-4770-8 . Epub 2017 Mar 22. PMID: 28331959. Serpa Neto A, Deliberato RO, Johnson AEW, Bos LD, Amorim P, Pereira SM, Cazati DC, Cordioli RL, Correa TD, Pollard TJ, Schettino GPP, Timenetsky KT, Celi LA, Pelosi P, Gama de Abreu M, Schultz MJ; PROVE Network Investigators. Mechanical power of ventilation is associated with mortality in critically ill patients: an analysis of patients in two observational cohorts. Intensive Care Med. 2018;44(11):1914–1922. doi: 10.1007/s00134-018-5375-6 . Epub 2018 Oct 5. PMID: 30291378. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 10 Aug, 2025 Reviews received at journal 10 Aug, 2025 Reviewers agreed at journal 10 Aug, 2025 Reviews received at journal 09 Aug, 2025 Reviewers agreed at journal 07 Aug, 2025 Reviewers invited by journal 06 Aug, 2025 Editor assigned by journal 25 Jul, 2025 Submission checks completed at journal 24 Jul, 2025 First submitted to journal 24 Jul, 2025 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-7201588","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":498374609,"identity":"34a070a6-3f5a-4df8-b262-7ed709b95e4f","order_by":0,"name":"Edward R. KOST","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvUlEQVRIiWNgGAWjYBACCRDxgYEhAcpnJkoLY+MMBgMStTTzkKRFsr39+WPbtj958u3HH35gqLBObCCkRZrnjGFzbptBscGZHGMJhjPphLXISeQwgrQkbpDgYZBgbDtMjJb0h82WQC3zZ7A//sH4jwgt0hIJhs2MQC0NNxjMJBgbiNAi2XPGcGbPOePEDWdyzCwSjqUbE9Qicbz9wYcfZXKJ89uPP77xocZalqAWVJBAmvJRMApGwSgYBbgAADttPoYZA7jtAAAAAElFTkSuQmCC","orcid":"","institution":"University of Texas Health San Antonio","correspondingAuthor":true,"prefix":"","firstName":"Edward","middleName":"R.","lastName":"KOST","suffix":""},{"id":498374610,"identity":"a9a3170b-d15e-42aa-a548-b7aaf06052a3","order_by":1,"name":"Martin Goros","email":"","orcid":"","institution":"University of Texas Health San Antonio","correspondingAuthor":false,"prefix":"","firstName":"Martin","middleName":"","lastName":"Goros","suffix":""},{"id":498374611,"identity":"a8f64c6d-97ac-4b0e-8262-4944f28bc73a","order_by":2,"name":"Paulina Ramirez","email":"","orcid":"","institution":"University of Texas Health San Antonio","correspondingAuthor":false,"prefix":"","firstName":"Paulina","middleName":"","lastName":"Ramirez","suffix":""},{"id":498374612,"identity":"a3fe5b0b-8ef3-4da9-be23-7cdef76e97b4","order_by":3,"name":"Devin B. Burroughs","email":"","orcid":"","institution":"University Medicine Associates","correspondingAuthor":false,"prefix":"","firstName":"Devin","middleName":"B.","lastName":"Burroughs","suffix":""},{"id":498374613,"identity":"5187399a-d012-47ee-9451-4db86d8c226f","order_by":4,"name":"Jonathan Gelfond","email":"","orcid":"","institution":"University of Texas Health San Antonio","correspondingAuthor":false,"prefix":"","firstName":"Jonathan","middleName":"","lastName":"Gelfond","suffix":""},{"id":498374614,"identity":"54842663-3a26-4721-bea2-c79a64c3aac4","order_by":5,"name":"Georgia A. McCann","email":"","orcid":"","institution":"University of Texas Health San Antonio","correspondingAuthor":false,"prefix":"","firstName":"Georgia","middleName":"A.","lastName":"McCann","suffix":""}],"badges":[],"createdAt":"2025-07-24 05:23:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7201588/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7201588/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88891478,"identity":"dd57f35d-fa3f-49fb-91c4-a9ce46d703ff","added_by":"auto","created_at":"2025-08-12 12:50:31","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1263588,"visible":true,"origin":"","legend":"\u003cp\u003eillustrates the changes in peak Pplat and Cstat moving from baseline (intubated, supine position) to surgery in T/p. Median peak Pplat increased from 22.0 cmH₂O to 33.0 cmH₂O (p \u0026lt; 0.001), and median Cstat decreased from 33.3 to 16.7 mL/cmH₂O (p \u0026lt; 0.001), highlighting the pronounced effect of T/p on respiratory mechanics across all BMI categories.\u003c/p\u003e","description":"","filename":"Figure1JRSHighRes.png","url":"https://assets-eu.researchsquare.com/files/rs-7201588/v1/ff305abae361cb4deba5aa3e.png"},{"id":88891481,"identity":"1efe8322-9b50-4138-aef9-0f331f23a185","added_by":"auto","created_at":"2025-08-12 12:50:31","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":5119455,"visible":true,"origin":"","legend":"\u003cp\u003epresents the association between BMI and respiratory mechanics. At baseline, BMI was significantly associated with higher peak Pplat (β = 0.29 cmH₂O per kg/m²; 95% CI, 0.14–0.45; p \u0026lt; 0.001) and lower Cstat (β = –0.91 mL/cmH₂O per kg/m²; 95% CI, –1.26 to –0.57; p \u0026lt; 0.001). In contrast, no significant associations were seen between BMI and peak Pplat (p = 0.32) or Cstat (p = 0.663) during T/p, suggesting a physiologic convergence or saturation point in respiratory mechanics.\u003c/p\u003e","description":"","filename":"Figure2JRSHighRes.png","url":"https://assets-eu.researchsquare.com/files/rs-7201588/v1/8748c8adcddc3e81adf14e6a.png"},{"id":88896028,"identity":"c85bc14f-94c9-4721-809f-17c193dc4a65","added_by":"auto","created_at":"2025-08-12 13:06:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":8720188,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7201588/v1/38dad40f-47c4-4361-b972-898cb5153491.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Saturation of Respiratory Strain During Robotic Hysterectomy in Obese Women with Endometrial Cancer","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMinimally invasive surgery (MIS) is the standard of care for endometrial cancer (EC) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Compared to laparotomy, both conventional laparoscopy and robotic-assisted laparoscopic surgery (RALS) offer substantial perioperative advantages, including reduced blood loss, shorter hospitalization, less postoperative pain, faster recovery, and comparable oncologic outcomes [\u003cspan additionalcitationids=\"CR3 CR4\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAmong MIS techniques, RALS has become the preferred approach for obese patients with EC, who are at increased risk of surgical complications. Robotic systems provide enhanced dexterity, visualization, and ergonomics, facilitating complex pelvic procedures such as hysterectomy and lymphadenectomy in patients with high body mass index (BMI) or challenging anatomy.\u003c/p\u003e\u003cp\u003eMultiple studies have demonstrated the benefits of RALS over traditional laparoscopy in obese EC patients. A meta-analysis of over 10,000 cases found significantly lower conversion rates to laparotomy, particularly in those with BMI\u0026thinsp;\u0026ge;\u0026thinsp;40 kg/m\u0026sup2; [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Additional studies have reported reduced blood loss, shorter hospital stays, fewer complications, and similar cancer outcomes, in obese patients undergoing robotic hysterectomy, despite longer operative times [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDespite these advantages, RALS introduces anesthetic challenges due to the need for Trendelenburg positioning and pneumoperitoneum (T/p), both of which significantly impair respiratory mechanics. These factors elevate plateau airway pressures (Pplat), reduce static compliance (Cstat), and increase the risk of pulmonary complications such as atelectasis, transient hypoxemia, hypercapnia, and, rarely, barotrauma or ventilator-induced lung injury (VILI) [\u003cspan additionalcitationids=\"CR11 CR12\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Central obesity further compromises lung mechanics by reducing thoracic compliance, limiting functional residual capacity, and impairing oxygenation [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In this context, careful intraoperative monitoring of ventilatory parameters is essential to mitigate respiratory risk and optimize safety in obese patients undergoing robotic-assisted hysterectomy.\u003c/p\u003e\u003cp\u003eThis study evaluates the combined impact of obesity and T/p on intraoperative respiratory mechanics during robotic-assisted hysterectomy for endometrial cancer. Using five-minute interval sampling, we identified each patient\u0026rsquo;s peak Pplat to capture the moment of maximal ventilatory strain. During analysis, we observed a physiologic convergence, peak Pplat and Cstat values became statistically indistinguishable across BMI categories once T/p was established. This unanticipated finding suggests a saturation of respiratory strain, wherein the imposed mechanical load of surgical positioning and pneumoperitoneum exceeds the incremental impact of additional adiposity. This concept, described here as a \"ceiling effect\", emerges as a novel physiologic insight into ventilatory tolerance during robotic pelvic surgery.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003ePatient Selection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective cohort study was approved by the Institutional Review Boards (IRBs) of the University of Texas Health San Antonio and the University Hospital System (UHS). We identified 89 consecutive women with histologically confirmed endometrial carcinoma who underwent robotic-assisted total hysterectomy with surgical staging between 2011 and 2015.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSurgical Technique\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures were performed using the da Vinci Si Surgical System (Intuitive Surgical, Sunnyvale, CA) by board-certified gynecologic oncologists with assistance from obstetrics and gynecology residents. Surgical staging included total hysterectomy, bilateral salpingo-oophorectomy, and pelvic and/or para-aortic lymph node assessment, based on clinicopathologic findings [17]. Ovarian preservation was considered in premenopausal women with early-stage disease, at the discretion of the surgeon [18].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnesthesia Protocol and Intraoperative Management\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1. Induction and Maintenance of Anesthesia\u003c/strong\u003e General anesthesia was administered with endotracheal intubation following induction using midazolam, a short-acting opioid (typically fentanyl), and either propofol or etomidate. Neuromuscular blockade was achieved with rocuronium or succinylcholine. Maintenance anesthesia was provided using sevoflurane or desflurane, supplemented with intravenous opioids as needed. Anesthetic care was delivered by board-certified anesthesiologists with support from anesthesia residents and certified registered nurse anesthetists (CRNAs).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Physiologic Monitoring and Patient Positioning\u003c/strong\u003e Intraoperative monitoring included electrocardiography, pulse oximetry, capnography, core temperature (via esophageal or bladder probes), and non-invasive blood pressure. In select high-risk patients, radial arterial catheters were placed for beat-to-beat blood pressure monitoring and arterial blood gas sampling. Patients were positioned in dorsal lithotomy and secured per institutional protocol. Steep Trendelenburg positioning (~30°) was used throughout robotic access, and carbon dioxide pneumoperitoneum was maintained at 15 mm Hg.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. Intraoperative Ventilation Management\u003c/strong\u003e Anesthetic ventilation practices reflected institutional lung-protective strategies used from 2011 to 2015 [19]. Volume-controlled ventilation mode (VCV) was used for the majority of patients based on provider preference. Tidal volumes were generally maintained at 6–8 mL/kg ideal body weight, with PEEP typically set at 5–8 cmH₂O. FiO₂ was titrated to maintain oxygen saturation \u0026gt;94%, and respiratory rate was adjusted to ensure normocarbia. Recruitment maneuvers were selectively applied in cases of worsening compliance or oxygenation. Compliance-adjusted PEEP titration and advanced ventilatory monitoring techniques such as esophageal pressure-guided ventilation or electrical impedance tomography were not in routine use at the time.\u003c/p\u003e\n\u003cp\u003eVentilation mode, VCV or pressure-controlled ventilation mode (PCV), was individualized, with VCV favored for stable tidal volume delivery and PCV occasionally employed to reduce peak airway pressures. Ventilator settings were adjusted based on dynamic airway pressures, oxygenation, and patient-specific physiology.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4. Ventilatory Parameter Monitoring and Interpretation\u003c/strong\u003e Ventilatory parameters, including peak inspiratory pressure (PIP), tidal volume (TV), end-tidal CO₂, and dynamic compliance, were continuously displayed on the anesthesia workstation. PIP was evaluated at defined procedural checkpoints (e.g., post-intubation, post-insufflation, during Trendelenburg, and upon clinical changes).\u003c/p\u003e\n\u003cp\u003ePIP served as a practical screening metric for changes in resistance or compliance, but its composite nature limited its diagnostic specificity. When compliance-related concerns were raised, Pplat was measured using an inspiratory pause maneuver (typically 0.5–1.0 seconds). Pplat offered a more accurate surrogate for alveolar pressure and was selectively measured to differentiate between increased resistance (e.g., bronchospasm, secretions) and reduced lung compliance (e.g., pneumoperitoneum, Trendelenburg effects). In this cohort, Pplat was used as a confirmatory value in cases of elevated PIP, unexplained desaturation, or concern for excessive ventilatory load. Most patients had one or two intraoperative Pplat measurements, in line with standard practice during the study period. Though advanced monitoring tools were not employed, careful interpretation of ventilatory parameters enabled effective management, even in patients with morbid obesity.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1. Overview and Data Collection\u003c/strong\u003e This retrospective observational study analyzed ventilatory data and clinical outcomes in consecutive women undergoing robotic-assisted hysterectomy between 2011 and 2015. Demographic, surgical, anesthetic, and pathologic variables were abstracted post hoc from the electronic medical record (EMR).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Intraoperative Respiratory Data Acquisition\u003c/strong\u003e During surgery respiratory mechanics were continuously recorded and automatically archived using the Servo-i ventilator system (Servo Screen 390 V2.0, Siemens-Elma AB). Data were retrospectively sampled from archived anesthetic records at standardized five-minute intervals. At each timepoint, values for PIP, Pplat, TV, respiratory rate, PEEP, and FiO₂ were reviewed. No real-time data were collected; all values were extracted retrospectively.\u003c/p\u003e\n\u003cp\u003eBaseline respiratory measurements were obtained immediately following anesthesia induction with the patient in the supine position, after confirmation of hemodynamic stability. Subsequent measurements were recorded during the surgery with the patient in T/p, at 5-minute intervals. The peak Pplat was defined as the highest recorded Pplat during the surgery in T/p.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. Peak Plateau Pressure as Anchor for Respiratory Analysis\u003c/strong\u003e Each patient’s ventilatory dataset was reviewed to identify the five-minute interval with the highest Pplat. This peak Pplat timepoint served as the physiologic anchor for all respiratory analyses. Additional parameters captured at this interval were used to calculate Cstat, using the formula:\u003c/p\u003e\n\u003cp\u003eCstat = Tidal Volume (TV) / (Pplat – PEEP)\u003c/p\u003e\n\u003cp\u003eAll values were taken from the peak Pplat interval, ensuring a standardized, high-strain reference point for each patient. This method allowed for physiologic comparisons across a heterogeneous surgical cohort.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4. Justification for Five-Minute Pplat Sampling Strategy\u003c/strong\u003e A five-minute retrospective sampling interval was selected to balance feasibility with physiologic resolution. Shorter intervals were impractical for retrospective review, while longer intervals risked missing transient but meaningful spikes in airway pressure. Thus, a five-minute sampling interval was selected as a feasible and physiologically informative compromise.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eContinuous variables were expressed as mean ± standard deviation (SD) or median and interquartile range (IQR), depending on distribution assessed via histograms, Q–Q plots, and the Shapiro–Wilk test. Categorical variables were reported as frequencies and percentages.\u003c/p\u003e\n\u003cp\u003eOne-way ANOVA was used to compare continuous variables across BMI categories. Post hoc pairwise comparisons were conducted as appropriate. The Wilcoxon signed-rank test was used for paired comparisons between baseline (post-intubation, supine) and during surgery in Trendelenburg position with pneumoperitoneum. Chi-square (χ²) or Fisher’s exact tests were used for categorical data.\u003c/p\u003e\n\u003cp\u003eLinear regression was used to explore the relationship between BMI and respiratory mechanics (e.g., peak Pplat, Cstat) at baseline (post-intubation, supine) and during surgery in Trendelenburg position with pneumoperitoneum. Regression coefficients and 95% confidence intervals (CI) were reported. Given the exploratory nature and modest sample size, covariate adjustments (e.g., age, ASA class) and interaction terms (e.g., BMI × surgical time) were not included. No adjustments for multiple comparisons were applied to preserve statistical power. Missing data were minimal (\u0026lt;5%) and managed using complete case analysis. All p-values were two-tailed, with significance defined as p \u0026lt; 0.05. All statistical analyses were conducted using SPSS version 29.0 (IBM Corp., Armonk, NY).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cb\u003ePatient Demographics, Tumor Characteristics, and Perioperative Metrics\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA total of 89 women underwent robotic-assisted hysterectomy for endometrial cancer and were included in this retrospective analysis. The mean BMI for the cohort was 37.5\u0026thinsp;\u0026plusmn;\u0026thinsp;9.9 kg/m\u0026sup2;. Class III obesity (BMI\u0026thinsp;\u0026ge;\u0026thinsp;40 kg/m\u0026sup2;) was observed in 40.4% of patients, with 10.1% classified as BMI\u0026thinsp;\u0026ge;\u0026thinsp;50 kg/m\u0026sup2;. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes demographic, tumor, and perioperative characteristics stratified by BMI.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic, Pathologic, and Perioperative Characteristics Stratified by Body Mass Index (BMI) Category\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable (unit)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;30\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;22)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u0026ndash;34.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e35\u0026ndash;39.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e40\u0026ndash;44.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;16)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e45\u0026ndash;49.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;50\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eTotal\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;89)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e37.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e42.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e47.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e56.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e37.5\u0026thinsp;\u0026plusmn;\u0026thinsp;9.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60.2\u0026thinsp;\u0026plusmn;\u0026thinsp;11.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e60.7\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e51.6\u0026thinsp;\u0026plusmn;\u0026thinsp;14.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e54.4\u0026thinsp;\u0026plusmn;\u0026thinsp;9.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e43.7\u0026thinsp;\u0026plusmn;\u0026thinsp;14.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e47.1\u0026thinsp;\u0026plusmn;\u0026thinsp;9.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e54.5\u0026thinsp;\u0026plusmn;\u0026thinsp;12.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor Grade 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7 (31.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5 (33.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13 (72.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10 (62.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7 (77.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e7 (77.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e49 (55.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor Grade 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7 (31.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6 (40.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6 (37.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e27 (30.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor Grade 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (36.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (26.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (5.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e13 (14.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003e0.013\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor Stage \u0026ndash; I\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14 (63.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9 (60.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17 (94.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e12 (75.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e9 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e70 (78.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor Stage \u0026ndash; II\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (9.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (26.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (5.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (6.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e8 (9.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor Stage \u0026ndash; III\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6 (27.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (13.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3 (18.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e11 (12.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003e0.039\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHistology \u0026ndash; Low Risk\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17 (77.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13 (86.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e18 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e16 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e9 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e82 (97.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHistology \u0026ndash; High Risk\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5 (22.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (13.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e7 (2.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003e0.033\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLN Procedure \u0026ndash; None\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9 (40.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5 (33.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11 (61.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7 (43.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8 (88.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e7 (77.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e47 (52.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLN Procedure \u0026ndash; Pelvic Only\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6 (27.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (26.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5 (31.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1 (11.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e20 (22.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLN Procedure \u0026ndash; Pelvic\u0026thinsp;+\u0026thinsp;Para-aortic\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7 (31.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6 (40.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3 (16.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4 (25.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e22 (24.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.200\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePelvic LN Count\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21.2\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22.6\u0026thinsp;\u0026plusmn;\u0026thinsp;13.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e23.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e26.9\u0026thinsp;\u0026plusmn;\u0026thinsp;8.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e42.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e48.5\u0026thinsp;\u0026plusmn;\u0026thinsp;36.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e25.0\u0026thinsp;\u0026plusmn;\u0026thinsp;12.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003e0.039\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePara-aortic LN Count\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e12.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN\u0026thinsp;=\u0026thinsp;0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e12.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e9.6\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.769\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUterine Weight (g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e153.9\u0026thinsp;\u0026plusmn;\u0026thinsp;89.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e144.4\u0026thinsp;\u0026plusmn;\u0026thinsp;107.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e160.4\u0026thinsp;\u0026plusmn;\u0026thinsp;90.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e168.8\u0026thinsp;\u0026plusmn;\u0026thinsp;94.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e128.7\u0026thinsp;\u0026plusmn;\u0026thinsp;59.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e180.2\u0026thinsp;\u0026plusmn;\u0026thinsp;75.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e156.4\u0026thinsp;\u0026plusmn;\u0026thinsp;88.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.835\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEstimated Blood Loss (mL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e143.0\u0026thinsp;\u0026plusmn;\u0026thinsp;115.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e109.7\u0026thinsp;\u0026plusmn;\u0026thinsp;65.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e182.5\u0026thinsp;\u0026plusmn;\u0026thinsp;207.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e218.4\u0026thinsp;\u0026plusmn;\u0026thinsp;232.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e165.0\u0026thinsp;\u0026plusmn;\u0026thinsp;147.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e155.6\u0026thinsp;\u0026plusmn;\u0026thinsp;72.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e162.4\u0026thinsp;\u0026plusmn;\u0026thinsp;158.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.515\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLength of Stay (hrs)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e45.4\u0026thinsp;\u0026plusmn;\u0026thinsp;17.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51.9\u0026thinsp;\u0026plusmn;\u0026thinsp;28.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e59.0\u0026thinsp;\u0026plusmn;\u0026thinsp;69.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e47.9\u0026thinsp;\u0026plusmn;\u0026thinsp;62.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e51.6\u0026thinsp;\u0026plusmn;\u0026thinsp;28.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e52.1\u0026thinsp;\u0026plusmn;\u0026thinsp;23.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e51.0\u0026thinsp;\u0026plusmn;\u0026thinsp;43.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.620\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAny Complication\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (13.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (20.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7 (38.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4 (25.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1 (11.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e20 (22.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.649\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIOC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (4.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (5.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (6.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3 (3.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.861\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePOC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (13.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2 (12.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1 (11.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e11 (12.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.352\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTransfusion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (9.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (6.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2 (11.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (6.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6 (6.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.843\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUrgent Care or ER Visit\u0026thinsp;\u0026ge;\u0026thinsp;1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6 (27.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (13.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5 (27.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4 (25.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3 (33.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e22 (24.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.53\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eData are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) for continuous variables and as number (percentage) for categorical variables.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eBMI\u0026thinsp;=\u0026thinsp;Body Mass Index (kg/m\u0026sup2;); LN\u0026thinsp;=\u0026thinsp;Lymph Node; IOC\u0026thinsp;=\u0026thinsp;Intraoperative Complication; POC\u0026thinsp;=\u0026thinsp;Postoperative Complication.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eP-values were calculated using one-way ANOVA for continuous variables and chi-square or Fisher\u0026rsquo;s exact test for categorical variables.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eBolded P-values indicate statistical significance (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePatient age varied significantly by BMI category, with younger patients more commonly represented in the higher BMI groups (p\u0026thinsp;=\u0026thinsp;0.002). Tumor biology also differed across BMI strata. Grade 1 (low-grade) tumors were more prevalent in higher BMI categories (p\u0026thinsp;=\u0026thinsp;0.013), while Grade 3 tumors were restricted to patients with BMI\u0026thinsp;\u0026lt;\u0026thinsp;40 kg/m\u0026sup2;. Similarly, Stage I disease predominated in higher BMI groups (p\u0026thinsp;=\u0026thinsp;0.039), whereas Stage III disease was seen exclusively in patients with BMI\u0026thinsp;\u0026lt;\u0026thinsp;45. High-risk histologic subtypes were rare (7 of 89 patients, 2.2%), occurring only in the lowest and mid-range BMI groups (p\u0026thinsp;=\u0026thinsp;0.033).\u003c/p\u003e\u003cp\u003eLymphadenectomy was performed in 47.2% of patients, without significant variation in lymph node procedure type (pelvic and para-aortic) across BMI categories (p\u0026thinsp;=\u0026thinsp;0.200). However, pelvic lymph node yield increased significantly with increasing BMI (p\u0026thinsp;=\u0026thinsp;0.039), while para-aortic node counts did not (p\u0026thinsp;=\u0026thinsp;0.769). Uterine weight, estimated blood loss, and length of hospital stay were not significantly associated with BMI (p\u0026thinsp;=\u0026thinsp;0.835, p\u0026thinsp;=\u0026thinsp;0.515, and p\u0026thinsp;=\u0026thinsp;0.620, respectively).\u003c/p\u003e\u003cp\u003eA total of 20 (22.5%) patients had any complications including intraoperative (3.4%), postoperative (12.4%), and blood transfusion (6.7%). However, the rates of complications did not differ by BMI group, Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Specific complication data is presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Pulmonary complications were seen in 4 patients (4.5%). Two patients required delayed extubation or reintubation, while one developed postoperative pneumonia and another experienced a pulmonary embolism. No patients suffered barotrauma or required prolonged mechanical ventilation (\u0026gt;\u0026thinsp;24 hours). Only one case (1.1%) required conversion to laparotomy, performed to address a vascular injury unrelated to respiratory mechanics. For transparency, we included all complications in our totals including minor complications consisting of 4 cases of trocar site infections (wound infections) and 3 cases of postoperative slow return of bowel function (ileus).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePerioperative Complications Among Patients Undergoing Robotic-Assisted Hysterectomy\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComplication\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePulmonary complications\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (4.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDelayed extubation or reintubation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePneumonia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePulmonary embolism\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAll-cause complications\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (11.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConversion to laparotomy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVascular injury\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUreteral injury\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWound infection\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePostoperative ileus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTransfusion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6 (6.7%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal patients with any complication\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20 (22.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"2\"\u003eComplications are presented as number (percentage) of the total cohort (N\u0026thinsp;=\u0026thinsp;89). Pulmonary complications include delayed extubation, pneumonia, pulmonary embolism, and reintubation. One conversion to laparotomy occurred for vascular repair. No cases of barotrauma or ventilator-induced lung injury (VILI) were observed.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eIntraoperative Anesthesia Parameters and Respiratory Mechanics\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e details intraoperative ventilatory and anesthetic characteristics by BMI. ASA classification did not differ significantly with BMI (p\u0026thinsp;=\u0026thinsp;0.496), with 77.5% of patients classified as ASA Class 3. Arterial line placement increased significantly with BMI (p\u0026thinsp;=\u0026thinsp;0.020), from 59.1% in patients with BMI\u0026thinsp;\u0026lt;\u0026thinsp;30 to 100% in those with BMI 45\u0026ndash;49.9, reflecting greater perceived anesthetic complexity in higher BMI patients.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eAnesthesia and Intraoperative Respiratory Mechanics Stratified by Body Mass Index (BMI) Category\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;30\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;22)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u0026ndash;34.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e35\u0026ndash;39.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e40\u0026ndash;44.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;16)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e45\u0026ndash;49.9\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;50\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eTotal\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;89)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eASA 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4 (18.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4 (27.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3 (17.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1 (11.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e12 (13.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.496\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eASA 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e17 (77.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10 (67.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e14 (78.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e14 (88.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e6 (67.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e8 (89.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e69 (77.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eASA 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1 (5.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1 (7.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1 (6.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2 (12.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2 (22.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e1 (11.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e8 (9.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eArterial Line\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13 (59.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9 (60.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e15 (83.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e14 (87.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e9 (100.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e8 (88.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e69 (77.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.020*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePIP (Baseline)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e20.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e23.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e25.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e27.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e29.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e24.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePIP, peak (T/p)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e38.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e40.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e39.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e40.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e40.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e41.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e40.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.198\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePplat (Baseline)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e18.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e20.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e21.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e22.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e23.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e25.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e21.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePplat, peak (T/p)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e33.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e35.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e35.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e34.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e36.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e34.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e35.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.167\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCstat (Baseline)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e39.4\u0026thinsp;\u0026plusmn;\u0026thinsp;8.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e33.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e36.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e33.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e31.4\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e29.4\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e34.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.002*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCstat, peak (T/p)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e17.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e15.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e18.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e18.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e15.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e16.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e17.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.129\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP/F Ratio (T/p)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e355.1\u0026thinsp;\u0026plusmn;\u0026thinsp;108.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e327.9\u0026thinsp;\u0026plusmn;\u0026thinsp;95.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e276.6\u0026thinsp;\u0026plusmn;\u0026thinsp;110.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e288.2\u0026thinsp;\u0026plusmn;\u0026thinsp;97.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e246.8\u0026thinsp;\u0026plusmn;\u0026thinsp;99.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e262.2\u0026thinsp;\u0026plusmn;\u0026thinsp;125.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e294.8\u0026thinsp;\u0026plusmn;\u0026thinsp;109.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.214\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOperative Time (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e259.7\u0026thinsp;\u0026plusmn;\u0026thinsp;71.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e246.7\u0026thinsp;\u0026plusmn;\u0026thinsp;73.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e235.5\u0026thinsp;\u0026plusmn;\u0026thinsp;85.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e260.1\u0026thinsp;\u0026plusmn;\u0026thinsp;72.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e329.6\u0026thinsp;\u0026plusmn;\u0026thinsp;338.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e251.3\u0026thinsp;\u0026plusmn;\u0026thinsp;57.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e258.9\u0026thinsp;\u0026plusmn;\u0026thinsp;125.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.610\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnesthesia Time (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e344.4\u0026thinsp;\u0026plusmn;\u0026thinsp;85.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e330.7\u0026thinsp;\u0026plusmn;\u0026thinsp;72.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e341.8\u0026thinsp;\u0026plusmn;\u0026thinsp;114.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e359.8\u0026thinsp;\u0026plusmn;\u0026thinsp;71.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e330.4\u0026thinsp;\u0026plusmn;\u0026thinsp;68.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e362.3\u0026thinsp;\u0026plusmn;\u0026thinsp;62.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e344.9\u0026thinsp;\u0026plusmn;\u0026thinsp;83.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.905\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIn room to cut, TTSS (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e59.7\u0026thinsp;\u0026plusmn;\u0026thinsp;15.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e60.8\u0026thinsp;\u0026plusmn;\u0026thinsp;13.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e62.5\u0026thinsp;\u0026plusmn;\u0026thinsp;12.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e66.7\u0026thinsp;\u0026plusmn;\u0026thinsp;18.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e72.8\u0026thinsp;\u0026plusmn;\u0026thinsp;11.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e73.6\u0026thinsp;\u0026plusmn;\u0026thinsp;14.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e64.6\u0026thinsp;\u0026plusmn;\u0026thinsp;15.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.085\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eValues are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) for continuous variables or number (percentage) for categorical variables.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eComparisons across BMI categories were performed using one-way ANOVA for continuous variables and chi-square or Fisher\u0026rsquo;s exact test for categorical variables.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003ePIP\u0026thinsp;=\u0026thinsp;Peak Inspiratory Pressure; Pplat\u0026thinsp;=\u0026thinsp;Plateau Pressure; Cstat\u0026thinsp;=\u0026thinsp;Static Lung Compliance; P/F Ratio\u0026thinsp;=\u0026thinsp;Arterial oxygen partial pressure to fractional inspired oxygen ratio (PaO₂/FiO₂); T/p\u0026thinsp;=\u0026thinsp;Trendelenburg positioning with pneumoperitoneum; TTSS\u0026thinsp;=\u0026thinsp;Time from operating room entry to surgical start; ASA\u0026thinsp;=\u0026thinsp;American Society of Anesthesiologists Physical Status Classification.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003eP-values\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered statistically significant.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAt baseline (intubated, supine, pre-insufflation), respiratory mechanics were significantly affected by BMI. Peak inspiratory pressure (PIP) increased from 20.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3 cmH₂O in the lowest BMI group to 29.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 cmH₂O in those with BMI\u0026thinsp;\u0026ge;\u0026thinsp;50 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Baseline Pplat similarly rose with increasing BMI (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), increasing from 18.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 to 25.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3 cmH₂O. Static compliance (Cstat) decreased significantly from 39.4\u0026thinsp;\u0026plusmn;\u0026thinsp;8.6 to 29.4\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4 mL/cmH₂O across the BMI range (p\u0026thinsp;=\u0026thinsp;0.002).\u003c/p\u003e\u003cp\u003eHowever, during T/p these BMI differences diminished. Peak PIP during T/p averaged 40.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0 cmH₂O and did not differ significantly across BMI categories (p\u0026thinsp;=\u0026thinsp;0.198). Similarly, peak Pplat reached a cohort mean of 35.0 cmH₂O and was statistically indistinguishable between BMI groups (p\u0026thinsp;=\u0026thinsp;0.167). Cstat values during T/p ranged from 17.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1 to 16.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1 mL/cmH₂O and did not differ significantly across BMI categories (p\u0026thinsp;=\u0026thinsp;0.129).\u003c/p\u003e\u003cp\u003eThe arterial oxygen partial pressure (PaO₂) to fractional inspired oxygen (FiO₂), (P/F ratio), during T/p showed a non-significant downward trend with increasing BMI (p\u0026thinsp;=\u0026thinsp;0.214), with the lowest average observed in the BMI 45\u0026ndash;49.9 group (246.8\u0026thinsp;\u0026plusmn;\u0026thinsp;99.7). Operative time, anesthesia duration, and in-room-to-incision time (TTSS) were similar across BMI groups (p\u0026thinsp;=\u0026thinsp;0.610, p\u0026thinsp;=\u0026thinsp;0.905, and p\u0026thinsp;=\u0026thinsp;0.085, respectively), although TTSS tended to be longer in patients with higher BMI.\u003c/p\u003e\u003cp\u003e\u003cb\u003eChanges in Respiratory Mechanics with T/p\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFigure 1 illustrates the changes in peak Pplat and Cstat moving from baseline (intubated, supine position) to surgery in T/p. Median peak Pplat increased from 22.0 cmH₂O to 33.0 cmH₂O (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and median Cstat decreased from 33.3 to 16.7 mL/cmH₂O (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), highlighting the pronounced effect of T/p on respiratory mechanics across all BMI categories.\u003c/p\u003e\u003cp\u003eFigure 2 presents the association between BMI and respiratory mechanics. At baseline, BMI was significantly associated with higher peak Pplat (β\u0026thinsp;=\u0026thinsp;0.29 cmH₂O per kg/m\u0026sup2;; 95% CI, 0.14\u0026ndash;0.45; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and lower Cstat (β = \u0026minus;\u0026thinsp;0.91 mL/cmH₂O per kg/m\u0026sup2;; 95% CI, \u0026minus;\u0026thinsp;1.26 to \u0026minus;\u0026thinsp;0.57; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In contrast, no significant associations were seen between BMI and peak Pplat (p\u0026thinsp;=\u0026thinsp;0.32) or Cstat (p\u0026thinsp;=\u0026thinsp;0.663) during T/p, suggesting a physiologic convergence or saturation point in respiratory mechanics.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e\u003cb\u003eKey Findings\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn this retrospective study of 89 women undergoing robotic-assisted hysterectomy for endometrial cancer, we found that surgery in T/p exerted the most significant influence on intraoperative respiratory mechanics, surpassing the effects of baseline obesity. While increased airway pressures and reduced lung compliance was associated with obesity at baseline, these differences were modest compared to the pronounced and uniform changes induced by T/p. Once insufflation and positioning were established, plateau pressures and static compliance values converged across BMI groups, highlighting the dominant role of surgical conditions in determining peak ventilatory strain.\u003c/p\u003e\u003cp\u003e\u003cb\u003eComparison to Existing Literature\u003c/b\u003e\u003c/p\u003e\u003cp\u003eOur findings align with prior reports demonstrating favorable perioperative outcomes in obese women undergoing robotic-assisted hysterectomy for endometrial cancer [\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In our cohort, the pulmonary complication rate was 4.5%, comparable to prior studies reporting rates below 5% in similar populations. For example, Wysham et al. reported a 3.0% complication rate in a multicenter analysis of 1,089 patients with age, but not BMI, identified as the primary predictor of pulmonary morbidity [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Similarly, Burke et al. found no association between BMI and postoperative respiratory outcomes, despite elevated intraoperative airway pressures in obese patients [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Eddib et al. also reported a low complication rate in obese women undergoing robotic hysterectomy, reinforcing the safety of this approach across BMI strata [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Collectively, our study and the above findings support the feasibility and safety of robotic surgery in high-BMI populations when modern anesthetic and lung-protective strategies are employed [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eWe observed that increasing BMI correlates with impaired baseline respiratory mechanics, i.e. before insufflation and Trendelenburg positioning. Specifically, patients with BMI\u0026thinsp;\u0026ge;\u0026thinsp;50 mg/m2 exhibited significantly higher baseline Pplat and lower Cstat compared to patients with BMI\u0026thinsp;\u0026lt;\u0026thinsp;30 mg/m2. These findings align with the restrictive ventilatory physiology of obesity, characterized by reduced thoracic compliance, increased intra-abdominal pressure, and diminished diaphragmatic excursion, leading to decreased functional residual capacity and a predisposition to atelectasis even before surgical intervention. Our observations are supported by previous studies that have documented similar impairments in respiratory mechanics among obese individuals [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOur findings align with prior studies demonstrating that T/p increases Pplat and decreases Cstat compared to the non-insufflated, supine position [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan additionalcitationids=\"CR25 CR26 CR27\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. However, unlike our results, several earlier investigations continued to report a linear or additive effect of increasing BMI on ventilatory strain even after T/p was established [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. This discrepancy may reflect key differences in data sampling strategies. Prior studies such as those by Tomescu et al. [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] and Tharp et al. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] collected ventilatory parameters at standardized intraoperative time points, typically post-induction, post-insufflation, mid-procedure, and end-of-case, regardless of what was occurring physiologically at those times. Similarly, Sprung et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] measured changes in pulmonary mechanics during pneumoperitoneum in laparoscopic surgery but did not dynamically track physiologic peaks. These fixed-time methods, while convenient, likely missed transient but clinically meaningful spikes in ventilatory pressure that occur during discrete surgical events. As a result, the plateau pressures they reported, typically 25\u0026ndash;32 cm H₂O, may underestimate the true peak mechanical stress, leading to continued identification of a linear relationship between Pplat and BMI.\u003c/p\u003e\u003cp\u003eIn contrast to prior studies, our methodology employed systematic five-minute interval sampling, allowing precise identification of individualized peak Pplat values across the cohort. This approach revealed consistent peak Pplat measurements of 35\u0026ndash;36 cm H₂O, confirming that our sampling strategy effectively captured transient periods of maximal mechanical load on the respiratory system. These Pplat peaks likely corresponded to specific intraoperative events\u0026mdash;such as trocar manipulation, specimen extraction, transient elevations in pneumoperitoneum pressure, and uterine manipulation\u0026mdash;that acutely increased intra-abdominal pressure. When superimposed on the baseline strain induced by T/p, these transient factors produced abrupt elevations in diaphragmatic load, thereby increasing Pplat.\u003c/p\u003e\u003cp\u003eThis study introduces the concept of a physiologic \u0026ldquo;ceiling effect\u0026rdquo; in intraoperative respiratory mechanics during robotic-assisted hysterectomy in obese women. As shown in Fig.\u0026nbsp;2, once T/p was established, Pplat values converged across all BMI categories, stabilizing at approximately 35\u0026ndash;36 cm H₂O. There was no statistically significant difference in peak Pplat among patients with BMI\u0026thinsp;\u0026lt;\u0026thinsp;30, 30\u0026ndash;39.9, 40\u0026ndash;49.9, and \u0026ge;\u0026thinsp;50 (p\u0026thinsp;=\u0026thinsp;NS), suggesting a saturation point beyond which further increases in BMI did not impose additional ventilatory strain. This implies that the combination of T/p and transient surgical events generates a maximal diaphragmatic load, after which additional adiposity has minimal incremental impact on thoracic compliance or diaphragmatic excursion. The resulting \u0026ldquo;ceiling effect\u0026rdquo; offers a novel framework for understanding ventilatory mechanics in obese patients and supports the feasibility of robotic hysterectomy across a broad BMI spectrum, particularly with lung-protective ventilation strategies.\u003c/p\u003e\u003cp\u003e\u003cb\u003eClinical and Scientific Implications and Future Research\u003c/b\u003e\u003c/p\u003e\u003cp\u003eOur findings challenge the assumption that BMI is a reliable predictor of intraoperative ventilatory burden. Once T/p was established, Pplat and Cstat converged across BMI categories, indicating that surgical positioning and insufflation\u0026mdash;not adiposity alone\u0026mdash;drive intraoperative respiratory load. Future studies should explore alternative physiologic phenotyping approaches that consider central adiposity, abdominal compliance, and thoracic geometry.\u003c/p\u003e\u003cp\u003eWhile Pplat and Cstat were our primary variables, we did not consistently capture driving pressure (ΔP\u0026thinsp;=\u0026thinsp;Pplat - PEEP) or mechanical power, both of which may better reflect the true mechanical forces acting on lung tissue. These parameters have shown promise in predicting ventilator-induced lung injury in critical care and intraoperative settings [\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Prospective studies using continuous monitoring of ΔP and mechanical power could refine real-time assessments of ventilatory strain and inform anesthetic decision-making in high-risk patients.\u003c/p\u003e\u003cp\u003eWe propose the term \"Surgical Lung Stress Load\" (SLSL) to describe the cumulative physiologic burden imposed by T/p, operative manipulation, and procedural duration on respiratory mechanics. Conceptually, SLSL parallels the critical care concept of mechanical power, representing the total energy applied to the lung\u0026mdash;but with emphasis on procedure-specific mechanical strain. Our data suggest that SLSL, not BMI, may be the dominant determinant of ventilatory strain. Quantifying SLSL in future studies may facilitate personalized ventilation strategies and advance risk stratification frameworks for minimally invasive surgery.\u003c/p\u003e\u003cp\u003eAs a hypothetical example, an anesthesiologist monitoring intraoperative Pplat and ΔP in a patient with BMI\u0026thinsp;\u0026ge;\u0026thinsp;50 might observe stable parameters following the onset of T/p, despite a temporary rise in Pplat to 35 cmH₂O. Understanding that this may reflect a ceiling state rather than progressive stress could help avoid unnecessary recruitment maneuvers, adjustments in Trendelenburg angle, or decreases in pneumoperitoneum pressure, especially in the absence of hypoxemia or hemodynamic instability.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStrengths\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis study offers several strengths. It is one of the few to examine intraoperative respiratory mechanics in a homogeneous cohort of obese women undergoing robotic-assisted hysterectomy, including a substantial proportion with class III and super obesity. Our use of individualized peak Pplat during T/p provides a physiologically grounded approach that reflects actual patient-specific stress points rather than arbitrary time intervals. This novel methodology allows for more accurate assessment of intrathoracic load and highlights transient but potentially important pressure elevations that may be missed with static sampling.\u003c/p\u003e\u003cp\u003eFinally, the absence of adverse pulmonary events despite frequent peak Pplat\u0026thinsp;\u0026gt;\u0026thinsp;35 cmH₂O reinforces the safety of robotic-assisted surgery in obese women when lung-protective strategies are employed.\u003c/p\u003e\u003cp\u003e\u003cb\u003eLimitations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWhile the proposed ceiling effect offers a meaningful physiologic insight, several intraoperative and anesthesia-related limitations must be considered when interpreting these findings.\u003c/p\u003e\u003cp\u003eFirst, we lacked intraoperative time-stamped data linking peak Pplat measurements to specific surgical or anesthetic events. This limits the ability to draw causal inferences. For example, anesthetic factors, including coughing, incomplete paralysis, ventilator-patient dyssynchrony, may also have contributed to peaks in pressure recordings.\u003c/p\u003e\u003cp\u003eSecond, anesthetic management was not standardized across the cohort. Differences in providers, ventilator settings, levels of PEEP, and use of recruitment maneuvers introduce variability that could influence both airway pressures and lung compliance.\u003c/p\u003e\u003cp\u003eThird, important respiratory metrics\u0026mdash;such as minute ventilation, end-tidal carbon dioxide (EtCO₂), and arterial carbon dioxide (PaCO₂)\u0026mdash;were not consistently available for study analysis. This limits our ability to assess ventilation adequacy or detect hypercapnia, especially in prolonged cases or those involving super obesity. Although no episodes of sustained hypoxemia were reported, reliance on intermittent arterial oxygen measurements (PaO₂) may have missed transient desaturation events. These are more common in obese patients under steep Trendelenburg with pneumoperitoneum due to reduced functional residual capacity and a predisposition to atelectasis. Moreover, the frequent use of high inspired oxygen fractions (FiO₂) may have masked early ventilation-perfusion mismatch or recruitment deficits.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study offers a novel physiologic perspective on intraoperative respiratory mechanics in obese women undergoing robotic-assisted hysterectomy. By employing individualized five-minute interval sampling, we identified a consistent convergence of plateau airway pressures across body mass index (BMI) categories once steep Trendelenburg positioning and carbon dioxide pneumoperitoneum were established. This pattern\u0026mdash;termed the \u0026ldquo;ceiling effect\u0026rdquo;\u0026mdash;suggests that surgical conditions, rather than obesity alone, are the dominant determinants of peak ventilatory strain. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress.\u003c/p\u003e\u003cp\u003eThese findings challenge conventional assumptions about the linear relationship between BMI and intraoperative respiratory burden. Importantly, they offer clinically actionable insights: once maximal mechanical load is imposed by positioning and insufflation, further adjustments to ventilation or intra-abdominal pressure may be unnecessary in hemodynamically stable patients\u0026mdash;even those with super obesity. This could inform more nuanced and efficient anesthetic management strategies during robotic pelvic surgery. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress.\u003c/p\u003e\u003cp\u003eWhile this retrospective study does not establish definitive clinical thresholds, it provides a physiologically grounded, hypothesis-generating framework for future research. Prospective studies using standardized anesthetic protocols, continuous waveform analysis, and real-time tracking of driving pressure and mechanical power are needed to validate these findings and explore the concept of surgical lung stress load as a practical tool for intraoperative risk assessment. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress.\u003c/p\u003e\u003cp\u003eIn summary, the recognition of a ceiling effect in respiratory strain advances our understanding of ventilatory physiology during robotic-assisted surgery and supports the safe, tailored application of minimally invasive approaches in obese surgical populations. These results contribute directly to the study objective by defining a novel physiologic ceiling in ventilatory stress.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank the Department of Anesthesiology and the Department of Obstetrics and Gynecology at the University of Texas Health San Antonio for their collaboration and support. We also acknowledge the University Hospital System IRB for data access and ethical review. Special thanks to the anesthesia providers and surgical residents whose clinical care enabled this retrospective analysis.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eConflict of Interest and Funding Disclosures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest related to this study. No external funding was received for this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Institutional Review Board (IRB) of the University of Texas Health Science Center at San Antonio (Protocol #HSC20150511H). The requirement for informed consent was waived due to the retrospective nature of the study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eE. K.: Conceptualization, study design, supervision, data interpretation, manuscript drafting, and critical revision. M. G.: Statistical analysis, data interpretation, and manuscript editing. J.G.: Statistical oversight, methodological guidance, and manuscript review. D. B.: Clinical interpretation of anesthetic data, manuscript review, and technical guidance on ventilatory parameters. G. M., P.R.: Study coordination, clinical validation, manuscript drafting, and critical manuscript revision. E.K., M.G., P.R., D.B., J.G., G.M.: made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work; drafted the work or revised it critically for important intellectual content; approved the 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/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eNational Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Uterine Neoplasms. Version 3.2025 \u0026mdash; March 7, 2025.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWalker JL, Piedmonte MR, Spirtos NM, Eisenkop SM, Schlaerth JB, Mannel RS, Spiegel G, Barakat R, Pearl ML, Sharma SK. Laparoscopy compared with laparotomy for comprehensive surgical staging of uterine cancer: Gynecologic Oncology Group Study LAP2. J Clin Oncol. 2009;27(32):5331\u0026ndash;6. doi: 10.1200/JCO.2009.22.3248. Epub 2009 Oct 5. PMID: 19805679; PMCID: PMC2773219.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWalker JL, Piedmonte MR, Spirtos NM, Eisenkop SM, Schlaerth JB, Mannel RS, Barakat R, Pearl ML, Sharma SK. Recurrence and survival after random assignment to laparoscopy versus laparotomy for comprehensive surgical staging of uterine cancer: Gynecologic Oncology Group LAP2 Study. J Clin Oncol. 2012;30(7):695\u0026ndash;700. doi: 10.1200/JCO.2011.38.8645. Epub 2012 Jan 30. Erratum in: J Clin Oncol. 2012;30(13):1570. PMID: 22291074; PMCID: PMC3295548.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKornblith AB, Huang HQ, Walker JL, Spirtos NM, Rotmensch J, Cella D. Quality of life of patients with endometrial cancer undergoing laparoscopic international federation of gynecology and obstetrics staging compared with laparotomy: a Gynecologic Oncology Group study. J Clin Oncol. 2009;27(32):5337-42. doi: 10.1200/JCO.2009.22.3529. Epub 2009 Oct 5. Erratum in: J Clin Oncol. 2010;28(16):2805. PMID: 19805678; PMCID: PMC2773220.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLindfors A, Heshar H, Adok C, Sundfeldt K, Dahm-K\u0026auml;hler P. Long-term survival in obese patients after robotic or open surgery for endometrial cancer. Gynecol Oncol. 2020;158(3):673\u0026ndash;680. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ygyno.2020.05.684\u003c/span\u003e\u003cspan address=\"10.1016/j.ygyno.2020.05.684\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2020 Jun 9. PMID: 32527569.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCusimano MC, Simpson AN, Dossa F, Liani V, Kaur Y, Acuna SA, Robertson D, Satkunaratnam A, Bernardini MQ, Ferguson SE, Baxter NN. Laparoscopic and robotic hysterectomy in endometrial cancer patients with obesity: a systematic review and meta-analysis of conversions and complications. Am J Obstet Gynecol. 2019;221(5):410\u0026ndash;428.e19. doi: 10.1016/j.ajog.2019.05.004. Epub 2019 May 10. PMID: 31082383.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYoshida K, Kondo E, Nimura R, Maki S, Kaneda M, Nii M, Ikeda T. Laparoscopic Versus Robotic Hysterectomy in Obese Patients With Early-stage Endometrial Cancer: A Single-centre Analysis. Anticancer Res. 2021;41(8):4163\u0026ndash;4167. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.21873/anticanres.15220\u003c/span\u003e\u003cspan address=\"10.21873/anticanres.15220\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 34281888.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCorrado G, Vizza E, Cela V, Mereu L, Bogliolo S, Legge F, Ciccarone F, Mancini E, Gallotta V, Baiocco E, Monterossi G, Perri MT, Zampa A, Pasciuto T, Scambia G. Laparoscopic versus robotic hysterectomy in obese and extremely obese patients with endometrial cancer: A multi-institutional analysis. Eur J Surg Oncol. 2018;44(12):1935\u0026ndash;1941. doi: 10.1016/j.ejso.2018.08.021. Epub 2018 Sep 15. PMID: 30245146.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLechartier C, Bernard J, Renaud MC, Plante M. Robotic-assisted surgery for endometrial cancer is safe in morbidly and extremely morbidly obese patients. Gynecol Oncol. 2023;172:15\u0026ndash;20. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ygyno.2023.02.014\u003c/span\u003e\u003cspan address=\"10.1016/j.ygyno.2023.02.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2023 Mar 9. PMID: 36905768.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSuh MK, Seong KW, Jung SH, Kim SS. The effect of pneumoperitoneum and Trendelenburg position on respiratory mechanics during pelviscopic surgery. Korean J Anesthesiol. 2010;59(5):329\u0026ndash;34. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.4097/kjae.2010.59.5.329\u003c/span\u003e\u003cspan address=\"10.4097/kjae.2010.59.5.329\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2010 Nov 25. PMID: 21179295; PMCID: PMC2998653.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSlutsky AS, Ranieri VM. Ventilator-induced lung injury. N Engl J Med. 2013;369(22):2126-36. doi: 10.1056/NEJMra1208707. Erratum in: N Engl J Med. 2014;370(17):1668-9. PMID: 24283226.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGattinoni L, Protti A, Caironi P, Carlesso E. Ventilator-induced lung injury: the anatomical and physiological framework. Crit Care Med. 2010;38(10 Suppl):S539-48. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/CCM.0b013e3181f1fcf7\u003c/span\u003e\u003cspan address=\"10.1097/CCM.0b013e3181f1fcf7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 21164395.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSprung J, Whalley DG, Falcone T, Warner DO, Hubmayr RD, Hammel J. The impact of morbid obesity, pneumoperitoneum, and posture on respiratory system mechanics and oxygenation during laparoscopy. Anesth Analg. 2002;94(5):1345-50. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00000539-200205000-00056\u003c/span\u003e\u003cspan address=\"10.1097/00000539-200205000-00056\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 11973218.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSprung J, Whalley DG, Falcone T, Wilks W, Navratil JE, Bourke DL. The effects of tidal volume and respiratory rate on oxygenation and respiratory mechanics during laparoscopy in morbidly obese patients. Anesth Analg. 2003;97(1):268\u0026thinsp;\u0026ndash;\u0026thinsp;74, table of contents. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1213/01.ane.0000067409.33495.1f\u003c/span\u003e\u003cspan address=\"10.1213/01.ane.0000067409.33495.1f\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 12818980.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePelosi P, Croci M, Ravagnan I, Tredici S, Pedoto A, Lissoni A, Gattinoni L. The effects of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia. Anesth Analg. 1998;87(3):654\u0026thinsp;\u0026ndash;\u0026thinsp;60. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00000539-199809000-00031\u003c/span\u003e\u003cspan address=\"10.1097/00000539-199809000-00031\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 9728848.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePelosi P, Gregoretti C. Perioperative management of obese patients. Best Pract Res Clin Anaesthesiol. 2010;24(2):211\u0026thinsp;\u0026ndash;\u0026thinsp;25. doi: 10.1016/j.bpa.2010.02.001. PMID: 20608558.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMariani A, Webb MJ, Keeney GL, Haddock MG, Calori G, Podratz KC. Low-risk corpus cancer: is lymphadenectomy or radiotherapy necessary? Am J Obstet Gynecol. 2000;182(6):1506-19. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1067/mob.2000.107335\u003c/span\u003e\u003cspan address=\"10.1067/mob.2000.107335\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 10871473.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWright JD, Buck AM, Shah M, Burke WM, Schiff PB, Herzog TJ. Safety of ovarian preservation in premenopausal women with endometrial cancer. J Clin Oncol. 2009;27(8):1214\u0026ndash;9. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1200/JCO.2008.19.8150\u003c/span\u003e\u003cspan address=\"10.1200/JCO.2008.19.8150\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2009 Jan 26. PMID: 19171707.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG\u0026uuml;ldner A, Kiss T, Serpa Neto A, Hemmes SN, Canet J, Spieth PM, Rocco PR, Schultz MJ, Pelosi P, Gama de Abreu M. Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers. Anesthesiology. 2015;123(3):692\u0026ndash;713. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/ALN.0000000000000754\u003c/span\u003e\u003cspan address=\"10.1097/ALN.0000000000000754\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 26120769.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWysham WZ, Kim KH, Roberts JM, Sullivan SA, Campbell SB, Roque DR, Moore DT, Gehrig PA, Boggess JF, Soper JT, Huh WK. Obesity and perioperative pulmonary complications in robotic gynecologic surgery. Am J Obstet Gynecol. 2015;213(1):33.e1-33.e7. doi: 10.1016/j.ajog.2015.01.033. Epub 2015 Jan 28. PMID: 25637843.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBurks C, Nelson L, Kumar D, Fogg L, Saha C, Guirguis A, Rotmensch J, Dewdney S. Evaluation of Pulmonary Complications in Robotic-Assisted Gynecologic Surgery. J Minim Invasive Gynecol. 2017;24(2):280\u0026ndash;285. doi: 10.1016/j.jmig.2016.11.001. Epub 2016 Nov 9. PMID: 27836798.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEddib A, Danakas A, Hughes S, Erk M, Michalik C, Narayanan MS, Krovi V, Singhal P. Influence of Morbid Obesity on Surgical Outcomes in Robotic-Assisted Gynecologic Surgery. J Gynecol Surg. 2014;30(2):81\u0026ndash;86. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1089/gyn.2012.0142\u003c/span\u003e\u003cspan address=\"10.1089/gyn.2012.0142\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 24803837; PMCID: PMC3995296.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSong Z, Sun L, Chen P, Yu Y. Lung-protective ventilation strategy to improve oxygenation function and respiratory mechanics in patients undergoing robotic bariatric surgery: A randomized double-blind trial (CONSORT). Medicine (Baltimore). 2025;104(6):e41433. doi: 10.1097/MD.0000000000041433. PMID: 39928832; PMCID: PMC11813022.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTharp WG, Murphy S, Breidenstein MW, Love C, Booms A, Rafferty MN, Friend AF, Perrapato S, Ahern TP, Dixon AE, Bates JHT, Bender SP. Body Habitus and Dynamic Surgical Conditions Independently Impair Pulmonary Mechanics during Robotic-assisted Laparoscopic Surgery. Anesthesiology. 2020;133(4):750\u0026ndash;763. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/ALN.0000000000003442\u003c/span\u003e\u003cspan address=\"10.1097/ALN.0000000000003442\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 32675698.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBlecha S, Harth M, Zeman F, Seyfried T, Lubnow M, Burger M, Denzinger S, Pawlik MT. The impact of obesity on pulmonary deterioration in patients undergoing robotic-assisted laparoscopic prostatectomy. J Clin Monit Comput. 2019;33(1):133\u0026ndash;143. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10877-018-0142-3\u003c/span\u003e\u003cspan address=\"10.1007/s10877-018-0142-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2018 Apr 16. PMID: 29663179.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTomescu DR, Popescu M, Dima SO, Bacalbașa N, Bubenek-Turconi Ș. Obesity is associated with decreased lung compliance and hypercapnia during robotic assisted surgery. J Clin Monit Comput. 2017;31(1):85\u0026ndash;92. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10877-016-9831-y\u003c/span\u003e\u003cspan address=\"10.1007/s10877-016-9831-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2016 Jan 28. PMID: 26823286; PMCID: PMC5253149.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRauh R, Hemmerling TM, Rist M, Jacobi KE. Influence of pneumoperitoneum and patient positioning on respiratory system compliance. J Clin Anesth. 2001;13(5):361-5. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/s0952-8180(01)00286-0\u003c/span\u003e\u003cspan address=\"10.1016/s0952-8180(01)00286-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 11498317.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKalmar AF, Foubert L, Hendrickx JF, Mottrie A, Absalom A, Mortier EP, Struys MM. Influence of steep Trendelenburg position and CO(2) pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy. Br J Anaesth. 2010;104(4):433\u0026ndash;9. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/bja/aeq018\u003c/span\u003e\u003cspan address=\"10.1093/bja/aeq018\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2010 Feb 18. PMID: 20167583.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAmato MB, Meade MO, Slutsky AS, Brochard L, Costa EL, Schoenfeld DA, Stewart TE, Briel M, Talmor D, Mercat A, Richard JC, Carvalho CR, Brower RG. Driving pressure and survival in the acute respiratory distress syndrome. N Engl J Med. 2015;372(8):747\u0026thinsp;\u0026ndash;\u0026thinsp;55. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1056/NEJMsa1410639\u003c/span\u003e\u003cspan address=\"10.1056/NEJMsa1410639\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 25693014.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGattinoni L, Tonetti T, Quintel M. Intensive care medicine in 2050: ventilator-induced lung injury. Intensive Care Med. 2018;44(1):76\u0026ndash;78. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00134-017-4770-8\u003c/span\u003e\u003cspan address=\"10.1007/s00134-017-4770-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2017 Mar 22. PMID: 28331959.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSerpa Neto A, Deliberato RO, Johnson AEW, Bos LD, Amorim P, Pereira SM, Cazati DC, Cordioli RL, Correa TD, Pollard TJ, Schettino GPP, Timenetsky KT, Celi LA, Pelosi P, Gama de Abreu M, Schultz MJ; PROVE Network Investigators. Mechanical power of ventilation is associated with mortality in critically ill patients: an analysis of patients in two observational cohorts. Intensive Care Med. 2018;44(11):1914\u0026ndash;1922. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00134-018-5375-6\u003c/span\u003e\u003cspan address=\"10.1007/s00134-018-5375-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2018 Oct 5. PMID: 30291378.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-robotic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jors","sideBox":"Learn more about [Journal of Robotic Surgery](http://link.springer.com/journal/11701)","snPcode":"11701","submissionUrl":"https://submission.nature.com/new-submission/11701/3","title":"Journal of Robotic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7201588/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7201588/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective:\u003c/h2\u003e\u003cp\u003eTo evaluate intraoperative ventilatory mechanics during robotic-assisted hysterectomy in obese women with endometrial cancer and introduce the concept of a physiologic \u0026ldquo;ceiling effect\u0026rdquo; in respiratory strain.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e\u003cp\u003eWe conducted a retrospective cohort study of 89 women with biopsy-confirmed endometrial cancer who underwent robotic-assisted total hysterectomy between 2011 and 2015. Intraoperative ventilatory parameters, including plateau airway pressure and static lung compliance, were recorded at five-minute intervals. Each patient\u0026rsquo;s peak plateau pressure was identified to calculate static compliance and estimate maximum ventilatory strain. Patients were stratified by body mass index (BMI), and ventilatory parameters were compared across BMI categories at baseline (post-induction, supine) and during steep Trendelenburg positioning with carbon dioxide pneumoperitoneum.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e\u003cp\u003eAt baseline, increasing BMI was significantly associated with higher plateau airway pressure and lower static compliance. For example, plateau pressure increased from 18.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 centimeters of water (cm H₂O) in patients with BMI less than 30 kilograms per square meter to 25.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3 cm H₂O in those with BMI greater than or equal to 50 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). However, following Trendelenburg positioning with pneumoperitoneum, peak plateau pressures converged across BMI categories, averaging 35.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3 cm H₂O (p\u0026thinsp;=\u0026thinsp;0.167). Static compliance also converged across BMI strata, averaging 17.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 milliliters per cm H₂O (p\u0026thinsp;=\u0026thinsp;0.129). Pulmonary complications occurred in 4.5% of patients, with no cases of barotrauma or prolonged mechanical ventilation.\u003c/p\u003e\u003ch2\u003eConclusions:\u003c/h2\u003e\u003cp\u003eIntraoperative ventilatory strain appears driven primarily by surgical positioning and pneumoperitoneum, rather than obesity alone. These findings support the feasibility and safety of robotic-assisted hysterectomy across a wide range of body mass index values and introduce the novel concept of a physiologic ceiling effect in ventilatory stress.\u003c/p\u003e","manuscriptTitle":"Saturation of Respiratory Strain During Robotic Hysterectomy in Obese Women with Endometrial Cancer","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-12 12:50:26","doi":"10.21203/rs.3.rs-7201588/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-11T01:34:18+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-11T01:30:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"172268695036346854593466746889312143084","date":"2025-08-10T20:24:26+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-09T13:05:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"46977998287807173092197719378730566","date":"2025-08-07T09:51:26+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-07T01:47:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-25T11:25:15+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-24T11:57:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Robotic Surgery","date":"2025-07-24T05:16:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-robotic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jors","sideBox":"Learn more about [Journal of Robotic Surgery](http://link.springer.com/journal/11701)","snPcode":"11701","submissionUrl":"https://submission.nature.com/new-submission/11701/3","title":"Journal of Robotic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7e8758f2-4258-41c9-be89-821449d9e862","owner":[],"postedDate":"August 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-08-29T12:23:22+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-12 12:50:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7201588","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7201588","identity":"rs-7201588","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}