Investigation of the Effects of Lung Protective Mechanical Ventilation in Robotic Surgeries Performed in Trendelenburg Position

Investigation of the Effects of Lung Protective Mechanical Ventilation in Robotic Surgeries Performed in Trendelenburg Position | 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 Investigation of the Effects of Lung Protective Mechanical Ventilation in Robotic Surgeries Performed in Trendelenburg Position esin tekin, nurdan bedirli, ömer kurtipek This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8527691/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Background and Goal of Study: Robotic surgery performed under general anesthesia with pneumoperitoneum and deep Trendelenburg positioning may adversely affect respiratory mechanics and gas exchange. Lung-protective ventilation strategies, including recruitment maneuvers (RM) and individualized positive end-expiratory pressure (PEEP), have been proposed to mitigate these effects. This study aimed to evaluate the effects of stepwise recruitment maneuvers combined with individualized PEEP on hemodynamic variables, respiratory mechanics, gas exchange, and postoperative respiratory outcomes in patients undergoing robotic surgery in the Trendelenburg position. Methods: After approval by the Gazi University Hospital Medical Research Ethics Committee, data of patients who underwent robotic surgery between 2012 and 2022 were retrospectively reviewed. Patients were divided into two groups: fixed PEEP (Group 1, n = 123) and individualized PEEP combined with recruitment maneuvers (Group 2, n = 135). Recruitment maneuvers were performed using a stepwise PEEP increase technique after intubation (T1), after pneumoperitoneum insufflation (T2), after positioning in Trendelenburg (T3), and after desufflation and position correction (T4). Demographic data, intraoperative hemodynamic parameters, respiratory variables, and postoperative respiratory outcomes were recorded. Continuous variables were analyzed using the Student’s t-test or Mann–Whitney U test, and categorical variables were compared using the χ² test. A p value < 0.05 was considered statistically significant. Results: Mean arterial pressure values showed transient reductions in the individualized PEEP group during Trendelenburg positioning. End-tidal CO₂ levels were lower in the individualized PEEP group during pneumoperitoneum and Trendelenburg positioning. Lung compliance was higher in patients receiving individualized PEEP at all measured intraoperative time points. Postoperative respiratory events were observed in both groups. Conclusion: In patients undergoing robotic surgery in the Trendelenburg position, stepwise recruitment maneuvers combined with individualized PEEP were associated with improved intraoperative respiratory mechanics without clinically significant hemodynamic instability. Figures Figure 1 INTRODUCTION Atelectasis can be expected in up to 90% of patients under general anesthesia [ 1 , 2 ]. Several mechanisms have been proposed for the development of atelectasis during general anesthesia, including collapse of small airways, compression of lung tissue, absorption of intraalveolar gas, and impairment of pulmonary surfactant function [ 1 ]. Mechanical ventilation strategies during general anesthesia have therefore been significantly influenced by the progressive decrease in oxygenation and lung compliance [ 1 ]. With the rapid advancement of minimally invasive surgical techniques, their use has expanded across many surgical procedures [ 3 ]. However, these surgeries are typically performed under general anesthesia in the Trendelenburg position with pneumoperitoneum. CO₂ pneumoperitoneum combined with the Trendelenburg position causes cephalad displacement of the diaphragm and mediastinal structures due to upward pressure from intra-abdominal contents. This results in a reduction in functional residual capacity (FRC), vital capacity, and lung compliance, as well as an increase in peak airway pressure (Ppeak), plateau pressure (Pplat), and ventilation–perfusion mismatch [ 4 ]. Lung compliance decreases by approximately 35% in the Trendelenburg position even without pneumoperitoneum, and pneumoperitoneum further exacerbates this reduction [ 5 , 6 ]. In addition, end-expiratory alveolar pressure may become insufficient to maintain alveolar patency, leading to the development of atelectasis. Consequently, lung-protective mechanical ventilation strategies have been developed to minimize these adverse effects. Various parameters, including tidal volume, positive end-expiratory pressure (PEEP), recruitment maneuvers (RM), and ventilator modes, have been investigated in the development of lung-protective mechanical ventilation strategies. Recruitment maneuvers, which are used to reopen atelectatic lung units, represent an important component of lung-protective ventilation and improve oxygenation and ventilation during anesthesia by reopening collapsed alveoli. They have also been shown to improve lung compliance and FRC [ 7 , 8 ]. Although there is no universally accepted consensus regarding the routine intraoperative use of RM, several well-recognized principles and guiding concepts have been described in the literature [ 7 ]. Fundamentally, reopening collapsed alveoli requires the application of high airway pressures or volumes. However, such approaches carry the potential risk of barotrauma, volutrauma, hemodynamic instability, and alveolocapillary injury. The selection of PEEP, a key element of lung-protective ventilation, should be individualized according to patient characteristics, surgical technique, and patient positioning rather than applying a uniform value to all patients. Recruitment maneuvers may be used to determine and maintain this individualized PEEP level. Although multiple RM techniques have been described, no single method has been identified as ideal. In the late 20th century, it was recognized that high tidal volumes were associated with ventilator-induced lung injury, leading to their avoidance in clinical practice [ 9 ]. Conversely, excessively low tidal volumes have also been discouraged, as they may contribute to the development of atelectasis [ 10 ]. To date, there is no clear consensus in the literature regarding the optimal lung-protective ventilation strategy during robotic surgery. Therefore, this study was designed to investigate the effects of recruitment maneuvers on blood pressure, heart rate, oxygen saturation, airway pressures, and lung compliance during intraoperative mechanical ventilation in patients undergoing robotic surgery in the Trendelenburg position. The secondary objective of the study was to evaluate the impact of the Trendelenburg position on postoperative respiratory complications, including prolonged extubation time, need for reintubation, atelectasis, pulmonary infection, and pneumothorax, during the recovery room period. MATERIALS AND METHODS Ethics approval and consent to participate The study protocol was approved by the Gazi University Hospital Medical Research Ethics Committee (Decision No: 2023/156). This study was conducted retrospectively using anonymized patient data. Due to the retrospective nature of the study and the use of previously collected clinical data, the requirement for informed consent to participate was waived by the Ethics Committee. All procedures involving human participants were performed in accordance with the ethical standards of the institutional research committee and with the principles of the Declaration of Helsinki. Following approval from the local ethics committee (Gazi University Hospital Medical Research Ethics Committee, 2023/156), this study was conducted retrospectively. Between 2012 and 2022, demographic characteristics, hemodynamic parameters, ventilation parameters, and intraoperative and postoperative anesthesia recovery room complications of patients who underwent robotic surgery in the deep Trendelenburg position in our clinic were retrospectively reviewed and recorded from patient files. The study data were generated from these records. Exclusion criteria included American Society of Anesthesiologists Physical Status (ASA) IV patients, patients with an individualized PEEP value of 5 cmH 2 O, patients with intraoperative surgical complications, cases converted to open surgery, and patients with incomplete or inadequate data. The information presented in Figure 1 was compiled from these records, and the obtained data were analyzed using appropriate statistical methods. Trial Design During the study period, data from 258 patients who underwent robotic surgery in the Trendelenburg position were included in the study. According to patient records, 123 patients received fixed PEEP, while 135 patients received individualized PEEP combined with recruitment maneuvers. Recruitment maneuvers were applied after intubation (T1), after insufflation (T2), after positioning (T3), and after desufflation and correction of position (T4). Patients were divided into two groups: the fixed PEEP group (Group 1) and the individualized PEEP group (Group 2). Statistical analyses were performed to compare outcomes between the two groups. Demographic data When the groups were compared, no statistically significant differences were observed in terms of ASA classification, age, history of hypertension, or smoking status (P > 0.05; Table 1). However, the prevalence of diabetes mellitus was significantly higher in patients in Group 1 compared with those in Group 2 (P < 0.05). Perioperative anesthesia management Standardized advanced monitoring, including pulse oximetry, electrocardiography, invasive arterial blood pressure, capnography, and temperature monitoring, was applied to all patients. Intravenous general anesthesia induction was performed using propofol (2–2.5 mg/kg), remifentanil infusion (0.2 µg/kg/min), and rocuronium (0.6 mg/kg). Following successful endotracheal intubation, mechanical ventilation was initiated with the following settings: positive end-expiratory pressure (PEEP) of 5 cmH₂O, tidal volume of 6–8 mL/kg, and respiratory rate of 12–16 breaths/min. After endotracheal intubation, invasive arterial cannulation was performed via the radial artery using a 20-gauge catheter. Anesthesia was maintained with 1 minimum alveolar concentration (MAC) sevoflurane and remifentanil infusion at a rate of 0.1–0.3 µg/kg/min. Following surgical preparation, pneumoperitoneum was established via intra-abdominal carbon dioxide insufflation after trocar and robotic arm placement, and patients were positioned in a 30° Trendelenburg position. At the completion of surgery and after surgical closure, patients were returned to the supine position. For postoperative analgesia, all patients received intravenous morphine (0.1 mg/kg), tramadol (1.5 mg/kg), and diclofenac (75 mg). Additionally, ondansetron 4 mg IV was administered for antiemetic prophylaxis. Neuromuscular blockade was reversed with sugammadex (4 mg/kg), and patients were extubated after achieving adequate spontaneous breathing and wakefulness. Postoperatively, patients were transferred to the recovery room. During recovery, intravenous tramadol (1 mg/kg) was administered to patients with a visual analog scale (VAS) score>4. Recruitment Maneuver Technique Recruitment maneuvers were performed using the “stepwise increase of PEEP” technique during pressure-controlled mechanical ventilation, as described in the literature. Peak airway pressure (Ppeak), driving pressure, and dynamic compliance were continuously monitored and recorded throughout the maneuver. The target peak airway pressure was 40–50 cmH₂O. PEEP was gradually increased starting from 5 cmH₂O, with increments of 5 cmH₂O at each step, and 3–5 breaths were delivered at each level. Once the target peak airway pressure was achieved, PEEP was gradually decreased. Mechanical ventilation was subsequently continued using the PEEP level at which driving pressure was lowest and lung compliance was highest. This value was recorded as the individualized PEEP. The target peak airway pressure range of 40–50 cmH₂O was selected to allow adequate alveolar recruitment while accounting for interindividual variability in chest wall compliance and intra-abdominal pressure during pneumoperitoneum and Trendelenburg positioning, in line with previously described recruitment strategies. In the individualized PEEP group, the applied PEEP levels ranged between 6 and 14 cmH₂O, reflecting interindividual variability in respiratory mechanics during robotic surgery in the Trendelenburg position. Because fixed PEEP was defined as 5 cmH₂O, patients with an individualized PEEP value of 5 cmH₂O were excluded from the study, and individualized PEEP was defined as >5 cmH₂O. In the fixed PEEP group, EtCO₂ values were maintained within clinically acceptable limits (25–59 mmHg); patients with values outside this range requiring intervention were excluded from the analysis. Data Collection and Outcomes Demographic characteristics, hemodynamic variables, and mechanical ventilation parameters were extracted from anesthesia records and documented. Lung compliance, PEEP, and SpO₂ values were compared at four predefined time points: after intubation (T1), after insufflation (T2), after positioning (T3), and after desufflation and repositioning (T4). The primary outcome of the study was intraoperative respiratory mechanics, specifically dynamic lung compliance and driving pressure at predefined intraoperative time points (T1–T4). Hemodynamic variables and postoperative respiratory outcomes were evaluated as secondary outcomes. Postoperative respiratory complications in the recovery room were compared between the two groups. Atelectasis and pneumothorax were diagnosed based on postoperative chest radiographs, while respiratory distress (defined as SpO₂ >90% with mask or nasal cannula support) and bronchospasm were identified from patient records. The primary outcome of the study was intraoperative respiratory mechanics, particularly lung compliance, while hemodynamic variables were evaluated as secondary safety outcomes. Statistical Analysis Statistical analyses were performed using SPSS version 21.0 (IBM Corp., Armonk, NY, USA). The normality of continuous variables was assessed using the Shapiro–Wilk test. Continuous variables with normal distribution were expressed as mean ± standard deviation, and non-normally distributed variables were expressed as median (interquartile range). Categorical variables were presented as frequency and percentage. Baseline demographic and perioperative variables were compared between the fixed PEEP and individualized PEEP groups using the Student’s t-test or Mann–Whitney U test, as appropriate. Categorical variables were compared using the χ² test or Fisher’s exact test when expected cell counts were less than 5. Repeated measurements of respiratory parameters (compliance, SpO₂ and PEEP) at different time points (T1, T2, T3, T4) were analyzed using repeated measures analysis of variance (RM-ANOVA) for normally distributed data, or the Friedman test for non-normally distributed data. When significant differences were detected, post hoc pairwise comparisons with Bonferroni correction were performed. Repeated measurements of hemodynamic parameters (MAP and EtCO₂) were also analyzed using RM-ANOVA or the Friedman test, as appropriate. A p-value <0.05 was considered statistically significant. RESULTS Intraoperative mean arterial pressure (MAP) values of the patients are presented in Table 2. In the intragroup comparison of MAP values, no statistically significant difference was observed in Group 1 (p> 0.05). In contrast, MAP in Group 2 was significantly lower at T3 compared with T1 and T4 (p <0.05). In the intergroup comparison, MAP values at T2 and T3 were significantly lower in Group 2 than in Group 1 (p <0.05). In the intragroup analysis, EtCO₂ values in Group 1 were significantly higher at T3 and T4 compared with T1 (p <0.01). In the intergroup comparison, EtCO₂ values at T3 and T4 were significantly higher in Group 1 than in Group 2 (p <0.001) (Table 3). Lung compliance values were significantly higher at all measurement time points in Group 2, which received individualized PEEP following recruitment maneuvers, compared with Group 1, which received fixed PEEP (p <0.05). Postoperative pulmonary complications are presented in Table 4. Reintubation was required in 2% of patients in Group 1, whereas 6% of patients in Group 2 developed respiratory distress that resolved with mask ventilation. DISCUSSION In the present study, mean arterial pressure values were lower in the individualized PEEP group during Trendelenburg positioning compared with the fixed PEEP group. However, these reductions were transient and did not require clinical intervention. End-tidal CO₂ values were higher in patients receiving fixed PEEP, particularly after positioning and desufflation. Lung compliance values, reflecting favorable respiratory mechanics, were consistently higher in patients receiving individualized PEEP following recruitment maneuvers. Robotic surgery has become increasingly common across multiple surgical specialties [11–15]. Nevertheless, pneumoperitoneum and Trendelenburg positioning are known to induce significant hemodynamic and respiratory changes. Several ventilation strategies, including PEEP application and recruitment maneuvers, have been proposed to attenuate these effects [16]. Recruitment maneuvers are an important component of lung-protective ventilation, as they reopen collapsed alveolar units and may improve oxygenation and lung compliance [7,8]. However, the optimal timing and technique of RM application during robotic surgery remain controversial. In the present study, stepwise recruitment maneuvers combined with individualized PEEP were applied at predefined intraoperative stages to evaluate their effects on respiratory mechanics and hemodynamic variables. Different RM techniques have been described in the literature [17]. In this study, RM was performed using a stepwise increase in PEEP under pressure-controlled ventilation. This approach was associated with higher lung compliance and lower EtCO₂ values during pneumoperitoneum and Trendelenburg positioning, suggesting improved ventilation efficiency. Recruitment maneuvers may also be associated with transient hemodynamic effects due to increased intrathoracic pressure [18,19]. In the present study, MAP values were transiently reduced during Trendelenburg positioning in the individualized PEEP group, consistent with previous reports [20–24]. These findings highlight the importance of careful monitoring during RM application. Pneumoperitoneum-related CO₂ absorption may contribute to elevated EtCO₂ levels during robotic surgery [25,26]. In the present study, EtCO₂ values were lower in patients receiving individualized PEEP, which may reflect improved respiratory mechanics and ventilation–perfusion matching. Lung compliance has been reported to decrease substantially during Trendelenburg positioning, with further reductions following pneumoperitoneum [5,6]. Consistent with previous findings, lung compliance decreased in both groups; however, values remained higher in patients receiving individualized PEEP throughout the intraoperative period. Postoperative respiratory events were observed in both groups. Although differences were noted, the retrospective design and lack of systematic postoperative imaging limit definitive conclusions regarding postoperative pulmonary complications. Although postoperative outcomes were not the primary focus of this retrospective analysis, the observed improvements in intraoperative respiratory mechanics may contribute to lung protection and warrant further prospective investigation. This study has several limitations that should be acknowledged. First, its retrospective design precludes the establishment of causal relationships between ventilation strategy and clinical outcomes. Second, the absence of randomization and the single-center nature of the study may limit the generalizability of the findings. In addition, postoperative pulmonary complications were identified based on clinical records rather than systematic imaging in all patients, which may have led to underestimation of their true incidence. Finally, although intraoperative respiratory mechanics were comprehensively evaluated, long-term postoperative pulmonary outcomes were not assessed. These limitations should be considered when interpreting the results, and prospective randomized studies are warranted to confirm our findings. CONCLUSION In conclusion, the intraoperative application of stepwise recruitment maneuvers combined with individualized PEEP was associated with improved respiratory mechanics and lower EtCO₂ levels during robotic surgery performed in the Trendelenburg position. This approach did not result in clinically significant hemodynamic instability. Individualized lung-protective ventilation strategies may be considered to optimize intraoperative respiratory management in this patient population. Declarations IRB: Gazi University Faculty of Medicine Clinical Research Ethics Committee (Decision No: 2023/156) Declaration of interest: The authors declare no conflicts of interest. Authors’ contributions: Esin Tekin and Nurdan Bedirli designed the study. Esin Tekin collected the data. Data interpretation was performed by Nurdan Bedirli and Omer Kurtipek. Statistical analyses were conducted by Nurdan Bedirli. All authors made substantial contributions to the work, participated in drafting the manuscript, and approved the final version. Data availability: The clinical data of this study are available from the corresponding author upon reasonable request. Funding: This study received no external funding. Abbreviations RM: Recruitment maneuver PEEP: Positive end-expiratory pressure MAP: Mean arterial pressure EtCO₂: End-tidal carbon dioxide PaO₂: Partial arterial oxygen pressure SpO₂: Peripheral oxygen saturation FRC: Functional residual capacity V/Q: Ventilation–perfusion ratio Ppeak: Peak airway pressure Pplat: Plateau pressure ECG: Electrocardiography MAC: Minimum alveolar concentration References Güldner A, Gama de M, Abreu. Intraoperative protective ventilation reduces postoperative pulmonary complications-PRO. Volume 50. Notfallmedizin, Schmerztherapie: AINS,: Intensivmedizin; 2015. pp. 524–8. 9Anasthesiologie. Hedenstierna G, et al. Functional residual capacity, thoracoabdominal dimensions, and central blood volume during general anesthesia with muscle paralysis and mechanical ventilation. Anesthesiology. 1985;62(3):247–54. Bedirli A et al. Our initial experience with robotic laparoscopic surgery. Turkish J Surg, 2012. 28(1). Estes J, Romeo RC. Patient Positioning and Common Nerve Injuries. Basic Clinical Anesthesia, 2015: pp. 631–636. Hirvonen EA, Nuutinen LS, Kauko M. Ventilatory effects, blood gas changes, and oxygen consumption during laparoscopic hysterectomy. Anesth Analg. 1995;80(5):961–6. Rauh R, et al. Influence of pneumoperitoneum and patient positioning on respiratory system compliance. J Clin Anesth. 2001;13(5):361–5. Putensen C, et al. Alveoläre Ventilation und Rekrutierung unter lungenprotektiver Beatmung. Anästhesiol Intensivmed Notfallmed Schmerzther. 2008;43(11/12):770–7. Oczenski W. Atmen-Atemhilfen: Atemphysiologie und Beatmungstechnik. Georg Thieme; 2008. Dreyfuss D, Saumon G. Ventilator-induced lung injury: lessons from experimental studies. Am J Respir Crit Care Med. 1998;157(1):294–323. Bendixen HH, Hedley-Whyte J, Laver MB. IMPAIRED OXYGENATION IN SURGICAL PATIENTS DURING GENERAL ANESTHESIA WITH CONTROLLED VENTILATION. A CONCEPT OF ATELECTASIS. N Engl J Med. 1963;269:991–6. Geiger JD, Hirschl RB. Innovation in surgical technology and techniques: Challenges and ethical issues. Semin Pediatr Surg. 2015;24(3):115–21. Menon M, et al. Prospective comparison of radical retropubic prostatectomy and robot-assisted anatomic prostatectomy: the Vattikuti Urology Institute experience. Urology. 2002;60(5):864–8. Bhayani SB, et al. Prospective comparison of short-term convalescence: laparoscopic radical prostatectomy versus open radical retropubic prostatectomy. Urology. 2003;61(3):612–6. Link RE, et al. Making ends meet: a cost comparison of laparoscopic and open radical retropubic prostatectomy. J Urol. 2004;172(1):269–74. Nelson B, et al. Comparison of length of hospital stay between radical retropubic prostatectomy and robotic assisted laparoscopic prostatectomy. J Urol. 2007;177(3):929–31. Topuz U et al. The Effects Of ‘Recruitment’Maneuver On Laparoscopic Colon Surgery . Amato MB, et al. Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndrome. N Engl J Med. 1998;338(6):347–54. Hess DR. Recruitment Maneuvers and PEEP Titration. Respir Care. 2015;60(11):1688–704. Bhattacharjee S, Soni KD, Maitra S. Recruitment maneuver does not provide any mortality benefit over lung protective strategy ventilation in adult patients with acute respiratory distress syndrome: a meta-analysis and systematic review of the randomized controlled trials. J Intensive Care. 2018;6:35. Reis Miranda D, et al. The open lung concept: effects on right ventricular afterload after cardiac surgery. Br J Anaesth. 2004;93(3):327–32. Huh JW, et al. Effect of the alveolar recruitment manoeuvre on haemodynamic parameters in patients with acute respiratory distress syndrome: relationship with oxygenation. Respirology. 2010;15(8):1220–5. Lovas A, Szakmány T. Haemodynamic Effects of Lung Recruitment Manoeuvres. Biomed Res Int, 2015. 2015: p. 478970. Min JY, et al. Prediction of hypotension during the alveolar recruitment maneuver in spine surgery: a prospective observational study. Eur J Med Res. 2023;28(1):64. Zhang X, et al. Robot-assisted versus laparoscopic-assisted surgery for colorectal cancer: a meta-analysis. Surg Endosc. 2016;30(12):5601–14. Wittgrove AC, Clark GW, Tremblay LJ. Laparoscopic Gastric Bypass, Roux-en-Y: Preliminary Report of Five Cases. Obes Surg. 1994;4(4):353–7. Sharma KC, et al. Cardiopulmonary physiology and pathophysiology as a consequence of laparoscopic surgery. Chest. 1996;110(3):810–5. Molloy B, Watson C. A comparative assessment of intraocular pressure in prolonged steep Trendelenburg position versus level supine position intervention. J Anesth Clin Sci, 2012. 1. Mills JT, et al. Positioning injuries associated with robotic assisted urological surgery. J Urol. 2013;190(2):580–4. Ulm MA, et al. Position-related injury is uncommon in robotic gynecologic surgery. Gynecol Oncol. 2014;135(3):534–8. Oksar M, et al. Anesthetic considerations for robotic cystectomy: a prospective study. Braz J Anesthesiol. 2014;64(2):109–15. Phong S, Koh L. Anaesthesia for robotic-assisted radical prostatectomy: considerations for laparoscopy in the Trendelenburg position. Anaesth Intensive Care. 2007;35(2):281–5. Barr C, et al. Cerebral oedema following robotic surgery: a rare complication. Arch Gynecol Obstet. 2014;290(5):1041–4. Berger JS et al. Anesthetic considerations for robot-assisted gynecologic and urology surgery. J Anesth Clin Res, 2013. 13(4). Tables Tablo 1. Demographic and perioperative characteristics of the patients Group 1 (n=123) Group 2 (n=135) Age 65±3 67±5 ASA classification (II/III) 52/71 65/70 History of hypertension (%) 58 53 History of diabetes (%) 18 5 β Smoking (%)** 12 28 Duration of anesthesia (minutes) 180±20 185±15 Surgical time (minutes) 168±30 176±40 *Standard Deviation ; b P 0.05) Table 2 Intraoperative mean arterial pressure Endtidal CO 2 (mmHg) Group 1 (n = 123) Mean ± SD Group 2 (n = 135) Mean ± SD Post intubation (T1) 35 ± 7 36 ± 5 After insufflation (T2) 35 ± 9 35 ± 7 After position (T3) 46 ± 13* β 37 ± 8 After desufflation (T4) 44 ± 11* β 38 ± 6 SD: standard deviation *P < 0.05: Compared with T1 measurement in intragroup comparison β P < 0.001 Compared to Group 2 Table 3 Intraoperative endtidal carbon dioxide Postoperative pulmonary complications Group 1 (n = 123) Group 2 (n = 135) Re-intubation (%) 2 0 Respiratory distress (%) 12 ∗ 6 Bronchospasm 2 3 ∗ P < 0.01, comparing groups 1 and 2 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 18 Mar, 2026 Reviewers agreed at journal 11 Mar, 2026 Reviewers invited by journal 09 Mar, 2026 Editor invited by journal 12 Feb, 2026 Editor assigned by journal 09 Jan, 2026 Submission checks completed at journal 08 Jan, 2026 First submitted to journal 08 Jan, 2026 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-8527691","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":604278838,"identity":"61aad9ea-14d8-4579-b78e-0562130f7e2c","order_by":0,"name":"esin tekin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6klEQVRIie3PsQrCMBCA4QsHTtGulUB9hUjA1QdxsYtbQXApOFgQ2kVwrYu+gi7OloIuha5CF0HwBVwcREwyCjWODvmXHEc+SABstr+MRPpwEchVT4jRL4QrgkINgMREdJIANJgmYCCOk8fXMTy9dtI8Tsfhc+AkkjzCfS1pp34iUuCCYWtUpQUP0pxEZFFU9S86k5hR4P4aaa9qxjyIJEES15N+mWkyU2SiyMZEOPiaDJkkqMjWRNyzJqK7mlPBaCGCnSTZt784y9NNEq/jlkX3TkMvWJd5dnmE9URHXh+Lw/f7NpvNZjP1BjFDSxQh5/yQAAAAAElFTkSuQmCC","orcid":"","institution":"Gülhane Training and Research Hospital","correspondingAuthor":true,"prefix":"","firstName":"esin","middleName":"","lastName":"tekin","suffix":""},{"id":604278839,"identity":"036e22c3-8e9e-458b-b8cf-2b0aa6473c3d","order_by":1,"name":"nurdan bedirli","email":"","orcid":"","institution":"Gazi University","correspondingAuthor":false,"prefix":"","firstName":"nurdan","middleName":"","lastName":"bedirli","suffix":""},{"id":604278840,"identity":"e7742d00-a5cd-4f78-a867-7ce14f61f6ca","order_by":2,"name":"ömer kurtipek","email":"","orcid":"","institution":"Gazi University","correspondingAuthor":false,"prefix":"","firstName":"ömer","middleName":"","lastName":"kurtipek","suffix":""}],"badges":[],"createdAt":"2026-01-06 07:08:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8527691/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8527691/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104554742,"identity":"6e2978c2-2985-4195-809a-69c891c7719e","added_by":"auto","created_at":"2026-03-13 08:58:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":49749,"visible":true,"origin":"","legend":"\u003cp\u003eData evaluated in the study\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8527691/v1/e7d3a266f9dce38cf9ef4748.png"},{"id":104554843,"identity":"ddaa4195-1cb4-4a73-b278-a41a31ead62a","added_by":"auto","created_at":"2026-03-13 08:58:13","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":746679,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8527691/v1/1e700fe7-91e4-4d70-a959-dc511518a3f9.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eInvestigation of the Effects of Lung Protective Mechanical Ventilation in Robotic Surgeries Performed in Trendelenburg Position\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eAtelectasis can be expected in up to 90% of patients under general anesthesia [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Several mechanisms have been proposed for the development of atelectasis during general anesthesia, including collapse of small airways, compression of lung tissue, absorption of intraalveolar gas, and impairment of pulmonary surfactant function [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Mechanical ventilation strategies during general anesthesia have therefore been significantly influenced by the progressive decrease in oxygenation and lung compliance [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWith the rapid advancement of minimally invasive surgical techniques, their use has expanded across many surgical procedures [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, these surgeries are typically performed under general anesthesia in the Trendelenburg position with pneumoperitoneum. CO₂ pneumoperitoneum combined with the Trendelenburg position causes cephalad displacement of the diaphragm and mediastinal structures due to upward pressure from intra-abdominal contents. This results in a reduction in functional residual capacity (FRC), vital capacity, and lung compliance, as well as an increase in peak airway pressure (Ppeak), plateau pressure (Pplat), and ventilation\u0026ndash;perfusion mismatch [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Lung compliance decreases by approximately 35% in the Trendelenburg position even without pneumoperitoneum, and pneumoperitoneum further exacerbates this reduction [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In addition, end-expiratory alveolar pressure may become insufficient to maintain alveolar patency, leading to the development of atelectasis. Consequently, lung-protective mechanical ventilation strategies have been developed to minimize these adverse effects.\u003c/p\u003e \u003cp\u003eVarious parameters, including tidal volume, positive end-expiratory pressure (PEEP), recruitment maneuvers (RM), and ventilator modes, have been investigated in the development of lung-protective mechanical ventilation strategies. Recruitment maneuvers, which are used to reopen atelectatic lung units, represent an important component of lung-protective ventilation and improve oxygenation and ventilation during anesthesia by reopening collapsed alveoli. They have also been shown to improve lung compliance and FRC [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Although there is no universally accepted consensus regarding the routine intraoperative use of RM, several well-recognized principles and guiding concepts have been described in the literature [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Fundamentally, reopening collapsed alveoli requires the application of high airway pressures or volumes. However, such approaches carry the potential risk of barotrauma, volutrauma, hemodynamic instability, and alveolocapillary injury.\u003c/p\u003e \u003cp\u003eThe selection of PEEP, a key element of lung-protective ventilation, should be individualized according to patient characteristics, surgical technique, and patient positioning rather than applying a uniform value to all patients. Recruitment maneuvers may be used to determine and maintain this individualized PEEP level. Although multiple RM techniques have been described, no single method has been identified as ideal. In the late 20th century, it was recognized that high tidal volumes were associated with ventilator-induced lung injury, leading to their avoidance in clinical practice [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Conversely, excessively low tidal volumes have also been discouraged, as they may contribute to the development of atelectasis [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo date, there is no clear consensus in the literature regarding the optimal lung-protective ventilation strategy during robotic surgery. Therefore, this study was designed to investigate the effects of recruitment maneuvers on blood pressure, heart rate, oxygen saturation, airway pressures, and lung compliance during intraoperative mechanical ventilation in patients undergoing robotic surgery in the Trendelenburg position. The secondary objective of the study was to evaluate the impact of the Trendelenburg position on postoperative respiratory complications, including prolonged extubation time, need for reintubation, atelectasis, pulmonary infection, and pneumothorax, during the recovery room period.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the Gazi University Hospital Medical Research Ethics Committee (Decision No: 2023/156).\u003c/p\u003e\n\u003cp\u003eThis study was conducted retrospectively using anonymized patient data. Due to the retrospective nature of the study and the use of previously collected clinical data, the requirement for informed consent to participate was waived by the Ethics Committee.\u003c/p\u003e\n\u003cp\u003eAll procedures involving human participants were performed in accordance with the ethical standards of the institutional research committee and with the principles of the Declaration of Helsinki.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFollowing approval from the local ethics committee (Gazi University Hospital Medical Research Ethics Committee, 2023/156), this study was conducted retrospectively. Between 2012 and 2022, demographic characteristics, hemodynamic parameters, ventilation parameters, and intraoperative and postoperative anesthesia recovery room complications of patients who underwent robotic surgery in the deep Trendelenburg position in our clinic were retrospectively reviewed and recorded from patient files. The study data were generated from these records.\u003c/p\u003e\n\u003cp\u003eExclusion criteria included American Society of Anesthesiologists Physical Status (ASA) IV patients, patients with an individualized PEEP value of 5 cmH\u003csub\u003e2\u003c/sub\u003eO, patients with intraoperative surgical complications, cases converted to open surgery, and patients with incomplete or inadequate data.\u003c/p\u003e\n\u003cp\u003eThe information presented in Figure 1 was compiled from these records, and the obtained data were analyzed using appropriate statistical methods.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial Design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the study period, data from 258 patients who underwent robotic surgery in the Trendelenburg position were included in the study. According to patient records, 123 patients received fixed PEEP, while 135 patients received individualized PEEP combined with recruitment maneuvers. Recruitment maneuvers were applied after intubation (T1), after insufflation (T2), after positioning (T3), and after desufflation and correction of position (T4).\u003c/p\u003e\n\u003cp\u003ePatients were divided into two groups: the fixed PEEP group (Group 1) and the individualized PEEP group (Group 2). Statistical analyses were performed to compare outcomes between the two groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDemographic data\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhen the groups were compared, no statistically significant differences were observed in terms of ASA classification, age, history of hypertension, or smoking status (P \u0026gt; 0.05; Table 1). However, the prevalence of diabetes mellitus was significantly higher in patients in Group 1 compared with those in Group 2 (P \u0026lt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePerioperative anesthesia management\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStandardized advanced monitoring, including pulse oximetry, electrocardiography, invasive arterial blood pressure, capnography, and temperature monitoring, was applied to all patients. Intravenous general anesthesia induction was performed using propofol (2–2.5 mg/kg), remifentanil infusion (0.2 µg/kg/min), and rocuronium (0.6 mg/kg). Following successful endotracheal intubation, mechanical ventilation was initiated with the following settings: positive end-expiratory pressure (PEEP) of 5 cmH₂O, tidal volume of 6–8 mL/kg, and respiratory rate of 12–16 breaths/min.\u003c/p\u003e\n\u003cp\u003eAfter endotracheal intubation, invasive arterial cannulation was performed via the radial artery using a 20-gauge catheter. Anesthesia was maintained with 1 minimum alveolar concentration (MAC) sevoflurane and remifentanil infusion at a rate of 0.1–0.3 µg/kg/min.\u003c/p\u003e\n\u003cp\u003eFollowing surgical preparation, pneumoperitoneum was established via intra-abdominal carbon dioxide insufflation after trocar and robotic arm placement, and patients were positioned in a 30° Trendelenburg position. At the completion of surgery and after surgical closure, patients were returned to the supine position.\u003c/p\u003e\n\u003cp\u003eFor postoperative analgesia, all patients received intravenous morphine (0.1 mg/kg), tramadol (1.5 mg/kg), and diclofenac (75 mg). Additionally, ondansetron 4 mg IV was administered for antiemetic prophylaxis. Neuromuscular blockade was reversed with sugammadex (4 mg/kg), and patients were extubated after achieving adequate spontaneous breathing and wakefulness. Postoperatively, patients were transferred to the recovery room. During recovery, intravenous tramadol (1 mg/kg) was administered to patients with a visual analog scale (VAS) score\u0026gt;4.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRecruitment Maneuver Technique\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Recruitment maneuvers were performed using the “stepwise increase of PEEP” technique during pressure-controlled mechanical ventilation, as described in the literature. Peak airway pressure (Ppeak), driving pressure, and dynamic compliance were continuously monitored and recorded throughout the maneuver.\u003c/p\u003e\n\u003cp\u003eThe target peak airway pressure was 40–50 cmH₂O. PEEP was gradually increased starting from 5 cmH₂O, with increments of 5 cmH₂O at each step, and 3–5 breaths were delivered at each level. Once the target peak airway pressure was achieved, PEEP was gradually decreased. Mechanical ventilation was subsequently continued using the PEEP level at which driving pressure was lowest and lung compliance was highest. This value was recorded as the individualized PEEP.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThe target peak airway pressure range of 40–50 cmH₂O was selected to allow adequate alveolar recruitment while accounting for interindividual variability in chest wall compliance and intra-abdominal pressure during pneumoperitoneum and Trendelenburg positioning, in line with previously described recruitment strategies.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the individualized PEEP group, the applied PEEP levels ranged between 6 and 14 cmH₂O, reflecting interindividual variability in respiratory mechanics during robotic surgery in the Trendelenburg position.\u003c/p\u003e\n\u003cp\u003eBecause fixed PEEP was defined as 5 cmH₂O, patients with an individualized PEEP value of 5 cmH₂O were excluded from the study, and individualized PEEP was defined as \u0026gt;5 cmH₂O. In the fixed PEEP group, EtCO₂ values were maintained within clinically acceptable limits (25–59 mmHg); patients with values outside this range requiring intervention were excluded from the analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Collection and Outcomes\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDemographic characteristics, hemodynamic variables, and mechanical ventilation parameters were extracted from anesthesia records and documented. Lung compliance, PEEP, and SpO₂ values were compared at four predefined time points: after intubation (T1), after insufflation (T2), after positioning (T3), and after desufflation and repositioning (T4). The primary outcome of the study was intraoperative respiratory mechanics, specifically dynamic lung compliance and driving pressure at predefined intraoperative time points (T1–T4). Hemodynamic variables and postoperative respiratory outcomes were evaluated as secondary outcomes.\u003c/p\u003e\n\u003cp\u003ePostoperative respiratory complications in the recovery room were compared between the two groups. Atelectasis and pneumothorax were diagnosed based on postoperative chest radiographs, while respiratory distress (defined as SpO₂ \u0026gt;90% with mask or nasal cannula support) and bronchospasm were identified from patient records.\u003c/p\u003e\n\u003cp\u003eThe primary outcome of the study was intraoperative respiratory mechanics, particularly lung compliance, while hemodynamic variables were evaluated as secondary safety outcomes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistical analyses were performed using SPSS version 21.0 (IBM Corp., Armonk, NY, USA).\u003cbr\u003e\u0026nbsp;The normality of continuous variables was assessed using the Shapiro–Wilk test. Continuous variables with normal distribution were expressed as mean ± standard deviation, and non-normally distributed variables were expressed as median (interquartile range). Categorical variables were presented as frequency and percentage.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBaseline demographic and perioperative variables were compared between the fixed PEEP and individualized PEEP groups using the Student’s t-test or Mann–Whitney U test, as appropriate. Categorical variables were compared using the χ² test or Fisher’s exact test when expected cell counts were less than 5.\u003c/p\u003e\n\u003cp\u003eRepeated measurements of respiratory parameters (compliance, SpO₂ and PEEP) at different time points (T1, T2, T3, T4) were analyzed using \u003cstrong\u003erepeated measures analysis of variance (RM-ANOVA)\u003c/strong\u003e for normally distributed data, or the \u003cstrong\u003eFriedman test\u003c/strong\u003e for non-normally distributed data. When significant differences were detected, post hoc pairwise comparisons with Bonferroni correction were performed. Repeated measurements of hemodynamic parameters (MAP and EtCO₂) were also analyzed using RM-ANOVA or the Friedman test, as appropriate.\u003c/p\u003e\n\u003cp\u003eA p-value \u0026lt;0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eIntraoperative mean arterial pressure (MAP) values of the patients are presented in Table 2. In the intragroup comparison of MAP values, no statistically significant difference was observed in Group 1 (p\u0026gt; 0.05). In contrast, MAP in Group 2 was significantly lower at T3 compared with T1 and T4 (p \u0026lt;0.05).\u0026nbsp;In the intergroup comparison, MAP values at T2 and T3 were significantly lower in Group 2 than in Group 1 (p \u0026lt;0.05).\u003c/p\u003e\n\u003cp\u003eIn the intragroup analysis, EtCO₂ values in Group 1 were significantly higher at T3 and T4 compared with T1 (p \u0026lt;0.01). In the intergroup comparison, EtCO₂ values at T3 and T4 were significantly higher in Group 1 than in Group 2 (p \u0026lt;0.001) (Table 3).\u003c/p\u003e\n\u003cp\u003eLung compliance values were significantly higher at all measurement time points in Group 2, which received individualized PEEP following recruitment maneuvers, compared with Group 1, which received fixed PEEP (p \u0026lt;0.05).\u003c/p\u003e\n\u003cp\u003ePostoperative pulmonary complications are presented in Table 4. Reintubation was required in 2% of patients in Group 1, whereas 6% of patients in Group 2 developed respiratory distress that resolved with mask ventilation.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn the present study, mean arterial pressure values were lower in the individualized PEEP group during Trendelenburg positioning compared with the fixed PEEP group. However, these reductions were transient and did not require clinical intervention. End-tidal CO₂ values were higher in patients receiving fixed PEEP, particularly after positioning and desufflation. Lung compliance values, reflecting favorable respiratory mechanics, were consistently higher in patients receiving individualized PEEP following recruitment maneuvers.\u003c/p\u003e\n\u003cp\u003eRobotic surgery has become increasingly common across multiple surgical specialties [11–15]. Nevertheless, pneumoperitoneum and Trendelenburg positioning are known to induce significant hemodynamic and respiratory changes. Several ventilation strategies, including PEEP application and recruitment maneuvers, have been proposed to attenuate these effects [16].\u003c/p\u003e\n\u003cp\u003eRecruitment maneuvers are an important component of lung-protective ventilation, as they reopen collapsed alveolar units and may improve oxygenation and lung compliance [7,8]. However, the optimal timing and technique of RM application during robotic surgery remain controversial. In the present study, stepwise recruitment maneuvers combined with individualized PEEP were applied at predefined intraoperative stages to evaluate their effects on respiratory mechanics and hemodynamic variables.\u003c/p\u003e\n\u003cp\u003eDifferent RM techniques have been described in the literature [17]. In this study, RM was performed using a stepwise increase in PEEP under pressure-controlled ventilation. This approach was associated with higher lung compliance and lower EtCO₂ values during pneumoperitoneum and Trendelenburg positioning, suggesting improved ventilation efficiency.\u003c/p\u003e\n\u003cp\u003eRecruitment maneuvers may also be associated with transient hemodynamic effects due to increased intrathoracic pressure [18,19]. In the present study, MAP values were transiently reduced during Trendelenburg positioning in the individualized PEEP group, consistent with previous reports [20–24]. These findings highlight the importance of careful monitoring during RM application.\u003c/p\u003e\n\u003cp\u003ePneumoperitoneum-related CO₂ absorption may contribute to elevated EtCO₂ levels during robotic surgery [25,26]. In the present study, EtCO₂ values were lower in patients receiving individualized PEEP, which may reflect improved respiratory mechanics and ventilation–perfusion matching.\u003c/p\u003e\n\u003cp\u003eLung compliance has been reported to decrease substantially during Trendelenburg positioning, with further reductions following pneumoperitoneum [5,6]. Consistent with previous findings, lung compliance decreased in both groups; however, values remained higher in patients receiving individualized PEEP throughout the intraoperative period.\u003c/p\u003e\n\u003cp\u003ePostoperative respiratory events were observed in both groups. Although differences were noted, the retrospective design and lack of systematic postoperative imaging limit definitive conclusions regarding postoperative pulmonary complications.\u003c/p\u003e\n\u003cp\u003eAlthough postoperative outcomes were not the primary focus of this retrospective analysis, the observed improvements in intraoperative respiratory mechanics may contribute to lung protection and warrant further prospective investigation.\u003c/p\u003e\n\u003cp\u003eThis study has several limitations that should be acknowledged. First, its retrospective design precludes the establishment of causal relationships between ventilation strategy and clinical outcomes. Second, the absence of randomization and the single-center nature of the study may limit the generalizability of the findings. In addition, postoperative pulmonary complications were identified based on clinical records rather than systematic imaging in all patients, which may have led to underestimation of their true incidence. Finally, although intraoperative respiratory mechanics were comprehensively evaluated, long-term postoperative pulmonary outcomes were not assessed. These limitations should be considered when interpreting the results, and prospective randomized studies are warranted to confirm our findings.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eIn conclusion, the intraoperative application of stepwise recruitment maneuvers combined with individualized PEEP was associated with improved respiratory mechanics and lower EtCO₂ levels during robotic surgery performed in the Trendelenburg position. This approach did not result in clinically significant hemodynamic instability. Individualized lung-protective ventilation strategies may be considered to optimize intraoperative respiratory management in this patient population.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eIRB:\u003c/strong\u003e Gazi University Faculty of Medicine Clinical Research Ethics Committee (Decision No: 2023/156)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of interest:\u003c/strong\u003e The authors declare no conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions:\u0026nbsp;\u003c/strong\u003eEsin Tekin and Nurdan Bedirli designed the study. Esin Tekin collected the data. Data interpretation was performed by Nurdan Bedirli and Omer Kurtipek. Statistical analyses were conducted by Nurdan Bedirli. All authors made substantial contributions to the work, participated in drafting the manuscript, and approved the final version.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability:\u003c/strong\u003e The clinical data of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This study received no external funding.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eRM: Recruitment maneuver\u003c/p\u003e\n\u003cp\u003ePEEP: Positive end-expiratory pressure\u003c/p\u003e\n\u003cp\u003eMAP: Mean arterial pressure\u003c/p\u003e\n\u003cp\u003eEtCO₂: End-tidal carbon dioxide\u003c/p\u003e\n\u003cp\u003ePaO₂: Partial arterial oxygen pressure\u003c/p\u003e\n\u003cp\u003eSpO₂: Peripheral oxygen saturation\u003c/p\u003e\n\u003cp\u003eFRC: Functional residual capacity\u003c/p\u003e\n\u003cp\u003eV/Q: Ventilation–perfusion ratio\u003c/p\u003e\n\u003cp\u003ePpeak: Peak airway pressure\u003c/p\u003e\n\u003cp\u003ePplat: Plateau pressure\u003c/p\u003e\n\u003cp\u003eECG: Electrocardiography\u003c/p\u003e\n\u003cp\u003eMAC: Minimum alveolar concentration\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eG\u0026uuml;ldner A, Gama de M, Abreu. Intraoperative protective ventilation reduces postoperative pulmonary complications-PRO. Volume 50. Notfallmedizin, Schmerztherapie: AINS,: Intensivmedizin; 2015. pp. 524\u0026ndash;8. 9Anasthesiologie.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHedenstierna G, et al. Functional residual capacity, thoracoabdominal dimensions, and central blood volume during general anesthesia with muscle paralysis and mechanical ventilation. Anesthesiology. 1985;62(3):247\u0026ndash;54.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBedirli A et al. Our initial experience with robotic laparoscopic surgery. Turkish J Surg, 2012. 28(1).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEstes J, Romeo RC. \u003cem\u003ePatient Positioning and Common Nerve Injuries.\u003c/em\u003e Basic Clinical Anesthesia, 2015: pp. 631\u0026ndash;636.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHirvonen EA, Nuutinen LS, Kauko M. Ventilatory effects, blood gas changes, and oxygen consumption during laparoscopic hysterectomy. Anesth Analg. 1995;80(5):961\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRauh R, et al. Influence of pneumoperitoneum and patient positioning on respiratory system compliance. J Clin Anesth. 2001;13(5):361\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePutensen C, et al. Alveol\u0026auml;re Ventilation und Rekrutierung unter lungenprotektiver Beatmung. An\u0026auml;sthesiol Intensivmed Notfallmed Schmerzther. 2008;43(11/12):770\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOczenski W. Atmen-Atemhilfen: Atemphysiologie und Beatmungstechnik. Georg Thieme; 2008.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDreyfuss D, Saumon G. Ventilator-induced lung injury: lessons from experimental studies. Am J Respir Crit Care Med. 1998;157(1):294\u0026ndash;323.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBendixen HH, Hedley-Whyte J, Laver MB. IMPAIRED OXYGENATION IN SURGICAL PATIENTS DURING GENERAL ANESTHESIA WITH CONTROLLED VENTILATION. A CONCEPT OF ATELECTASIS. N Engl J Med. 1963;269:991\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGeiger JD, Hirschl RB. Innovation in surgical technology and techniques: Challenges and ethical issues. Semin Pediatr Surg. 2015;24(3):115\u0026ndash;21.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMenon M, et al. Prospective comparison of radical retropubic prostatectomy and robot-assisted anatomic prostatectomy: the Vattikuti Urology Institute experience. Urology. 2002;60(5):864\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBhayani SB, et al. Prospective comparison of short-term convalescence: laparoscopic radical prostatectomy versus open radical retropubic prostatectomy. Urology. 2003;61(3):612\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLink RE, et al. Making ends meet: a cost comparison of laparoscopic and open radical retropubic prostatectomy. J Urol. 2004;172(1):269\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNelson B, et al. Comparison of length of hospital stay between radical retropubic prostatectomy and robotic assisted laparoscopic prostatectomy. J Urol. 2007;177(3):929\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTopuz U et al. \u003cem\u003eThe Effects Of \u0026lsquo;Recruitment\u0026rsquo;Maneuver On Laparoscopic Colon Surgery\u003c/em\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmato MB, et al. Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndrome. N Engl J Med. 1998;338(6):347\u0026ndash;54.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHess DR. Recruitment Maneuvers and PEEP Titration. Respir Care. 2015;60(11):1688\u0026ndash;704.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBhattacharjee S, Soni KD, Maitra S. Recruitment maneuver does not provide any mortality benefit over lung protective strategy ventilation in adult patients with acute respiratory distress syndrome: a meta-analysis and systematic review of the randomized controlled trials. J Intensive Care. 2018;6:35.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReis Miranda D, et al. The open lung concept: effects on right ventricular afterload after cardiac surgery. Br J Anaesth. 2004;93(3):327\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuh JW, et al. Effect of the alveolar recruitment manoeuvre on haemodynamic parameters in patients with acute respiratory distress syndrome: relationship with oxygenation. Respirology. 2010;15(8):1220\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLovas A, Szakm\u0026aacute;ny T. \u003cem\u003eHaemodynamic Effects of Lung Recruitment Manoeuvres.\u003c/em\u003e Biomed Res Int, 2015. 2015: p. 478970.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMin JY, et al. Prediction of hypotension during the alveolar recruitment maneuver in spine surgery: a prospective observational study. Eur J Med Res. 2023;28(1):64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang X, et al. Robot-assisted versus laparoscopic-assisted surgery for colorectal cancer: a meta-analysis. Surg Endosc. 2016;30(12):5601\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWittgrove AC, Clark GW, Tremblay LJ. Laparoscopic Gastric Bypass, Roux-en-Y: Preliminary Report of Five Cases. Obes Surg. 1994;4(4):353\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSharma KC, et al. Cardiopulmonary physiology and pathophysiology as a consequence of laparoscopic surgery. Chest. 1996;110(3):810\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMolloy B, Watson C. A comparative assessment of intraocular pressure in prolonged steep Trendelenburg position versus level supine position intervention. J Anesth Clin Sci, 2012. 1.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMills JT, et al. Positioning injuries associated with robotic assisted urological surgery. J Urol. 2013;190(2):580\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUlm MA, et al. Position-related injury is uncommon in robotic gynecologic surgery. Gynecol Oncol. 2014;135(3):534\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOksar M, et al. Anesthetic considerations for robotic cystectomy: a prospective study. Braz J Anesthesiol. 2014;64(2):109\u0026ndash;15.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhong S, Koh L. Anaesthesia for robotic-assisted radical prostatectomy: considerations for laparoscopy in the Trendelenburg position. Anaesth Intensive Care. 2007;35(2):281\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarr C, et al. Cerebral oedema following robotic surgery: a rare complication. Arch Gynecol Obstet. 2014;290(5):1041\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBerger JS et al. Anesthetic considerations for robot-assisted gynecologic and urology surgery. J Anesth Clin Res, 2013. 13(4).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\n\u003cp\u003eTablo 1. Demographic and perioperative characteristics of the patients\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\n\u003ctable width=\"604\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e\u003cstrong\u003eGroup 1\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;(n=123)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e\u003cstrong\u003eGroup 2\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(n=135)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e65\u0026plusmn;3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e67\u0026plusmn;5\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eASA classification (II/III)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e52/71\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e65/70\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eHistory of hypertension (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e58\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e53\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eHistory of diabetes (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e18\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e5\u003csup\u003e\u0026beta;\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eSmoking (%)**\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e12\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e28\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eDuration of anesthesia (minutes)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e180\u0026plusmn;20\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e185\u0026plusmn;15\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"245\"\u003e\n\u003cp\u003eSurgical time (minutes)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e168\u0026plusmn;30\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"180\"\u003e\n\u003cp\u003e176\u0026plusmn;40\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\n\u003cp\u003e*Standard Deviation ;\u003csup\u003eb\u003c/sup\u003eP \u0026lt;0,05: compared with Group 2\u003c/p\u003e\n\u003cp\u003e**No statistically significant difference was observed for smoking status between groups (P \u0026gt; 0.05)\u003c/p\u003e\n\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eIntraoperative mean arterial pressure\u003c/div\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eEndtidal CO\u003csub\u003e2\u003c/sub\u003e (mmHg)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup 1 (n\u0026thinsp;=\u0026thinsp;123)\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup 2 (n\u0026thinsp;=\u0026thinsp;135)\u003c/div\u003e\n\u003cdiv class=\"SimplePara\"\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/div\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003ePost intubation (T1)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e35\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e36\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAfter insufflation (T2)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e35\u0026thinsp;\u0026plusmn;\u0026thinsp;9\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e35\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAfter position (T3)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e46\u0026thinsp;\u0026plusmn;\u0026thinsp;13*\u003csup\u003e\u0026beta;\u003c/sup\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e37\u0026thinsp;\u0026plusmn;\u0026thinsp;8\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eAfter desufflation (T4)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e44\u0026thinsp;\u0026plusmn;\u0026thinsp;11*\u003csup\u003e\u0026beta;\u003c/sup\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e38\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003eSD: standard deviation\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003e*P\u0026thinsp;\u0026lt;\u0026thinsp;0.05: Compared with T1 measurement in intragroup comparison\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003e\u003csup\u003e\u0026beta;\u003c/sup\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.001 Compared to Group 2\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eIntraoperative endtidal carbon dioxide\u003c/div\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003ePostoperative pulmonary complications\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup 1 (n\u0026thinsp;=\u0026thinsp;123)\u003c/div\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eGroup 2 (n\u0026thinsp;=\u0026thinsp;135)\u003c/div\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eRe-intubation (%)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eRespiratory distress (%)\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e12\u003csup\u003e\u0026lowast;\u003c/sup\u003e\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e6\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003eBronchospasm\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e2\u003c/div\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cdiv class=\"SimplePara\"\u003e3\u003c/div\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003e\u003csup\u003e\u0026lowast;\u003c/sup\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.01, comparing groups 1 and 2\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-pulmonary-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pulm","sideBox":"Learn more about [BMC Pulmonary Medicine](http://bmcpulmmed.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pulm/default.aspx","title":"BMC Pulmonary Medicine","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-8527691/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8527691/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground and Goal of Study:\u003c/h2\u003e \u003cp\u003eRobotic surgery performed under general anesthesia with pneumoperitoneum and deep Trendelenburg positioning may adversely affect respiratory mechanics and gas exchange. Lung-protective ventilation strategies, including recruitment maneuvers (RM) and individualized positive end-expiratory pressure (PEEP), have been proposed to mitigate these effects. This study aimed to evaluate the effects of stepwise recruitment maneuvers combined with individualized PEEP on hemodynamic variables, respiratory mechanics, gas exchange, and postoperative respiratory outcomes in patients undergoing robotic surgery in the Trendelenburg position.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e \u003cp\u003e After approval by the Gazi University Hospital Medical Research Ethics Committee, data of patients who underwent robotic surgery between 2012 and 2022 were retrospectively reviewed. Patients were divided into two groups: fixed PEEP (Group 1, n\u0026thinsp;=\u0026thinsp;123) and individualized PEEP combined with recruitment maneuvers (Group 2, n\u0026thinsp;=\u0026thinsp;135). Recruitment maneuvers were performed using a stepwise PEEP increase technique after intubation (T1), after pneumoperitoneum insufflation (T2), after positioning in Trendelenburg (T3), and after desufflation and position correction (T4). Demographic data, intraoperative hemodynamic parameters, respiratory variables, and postoperative respiratory outcomes were recorded. Continuous variables were analyzed using the Student\u0026rsquo;s t-test or Mann\u0026ndash;Whitney U test, and categorical variables were compared using the χ\u0026sup2; test. A p value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e \u003cp\u003eMean arterial pressure values showed transient reductions in the individualized PEEP group during Trendelenburg positioning. End-tidal CO₂ levels were lower in the individualized PEEP group during pneumoperitoneum and Trendelenburg positioning. Lung compliance was higher in patients receiving individualized PEEP at all measured intraoperative time points. Postoperative respiratory events were observed in both groups.\u003c/p\u003e\u003ch2\u003eConclusion:\u003c/h2\u003e \u003cp\u003eIn patients undergoing robotic surgery in the Trendelenburg position, stepwise recruitment maneuvers combined with individualized PEEP were associated with improved intraoperative respiratory mechanics without clinically significant hemodynamic instability.\u003c/p\u003e","manuscriptTitle":"Investigation of the Effects of Lung Protective Mechanical Ventilation in Robotic Surgeries Performed in Trendelenburg Position","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-13 08:57:05","doi":"10.21203/rs.3.rs-8527691/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-03-18T07:57:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"22215746461755517802252367685637827597","date":"2026-03-11T08:17:53+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-09T06:09:33+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-02-12T08:07:09+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-09T09:11:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-08T16:27:33+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pulmonary Medicine","date":"2026-01-08T16:16:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pulmonary-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pulm","sideBox":"Learn more about [BMC Pulmonary Medicine](http://bmcpulmmed.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pulm/default.aspx","title":"BMC Pulmonary Medicine","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"be6bddee-21e2-4ab0-a1b7-a67c82fad022","owner":[],"postedDate":"March 13th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-13T08:57:08+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-13 08:57:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8527691","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8527691","identity":"rs-8527691","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}