Analysis of Factors Influencing Extended Post Anesthesia Care Unit Length of Stay (PACU-LOS) in Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy

Background The post anesthesia recovery phase following bariatric surgery is a high-risk period characterized by increased susceptibility to respiratory and hemodynamic complications, warranting prolonged monitoring and targeted interventions. Despite advancements in perioperative care, the identification of risk factors for extended recovery remains a critical unmet need in obese populations. Methods This single-center retrospective study analyzed 169 consecutive patients undergoing laparoscopic sleeve gastrectomy for metabolic syndrome and extubated in post anesthesia care unit (PACU) at Peking University Third Hospital (2015–2025). Patients were stratified by PACU length of stay (LOS) into extended (≥ 42 min, 75th percentile) and control (< 42 min) groups. Comprehensive perioperative variables were evaluated, including ‌preoperative data of demographic profiles, ASA physical status, BMI, obesity surgery mortality risk score (OS-MRS), and obstructive sleep apnea syndrome (OSAS) comorbidity; ‌Intraoperative and postoperative‌ data including procedure duration, hypoxemia incidence, pain scores, number of rescue antiemetic administered, postoperative complications, reoperation rates, length of hospital stay, 30-day readmission rates and mortality. Univariate analysis and logistic regression analysis. Were performed to find the risk factors of prolonged LOS. Results The extended PACU-LOS group (n = 45, 26.6%) demonstrated significantly higher BMI (40.6 [38.1, 47.2] vs. 38.7 [34.9, 44.0] kg/m², p  = 0.007), ASA III prevalence (66.7%% vs 25.8%, p  < 0.001), existence of OSAS (71.1% vs. 33.1%, p  < 0.001), intraoperative peak P _ET CO ₂ (41 [39, 46] vs. 39 [36, 42] p  < 0.001) and post-extubation hypoxemia incidence (62.2% vs. 9.7%, p  < 0.001). Multivariate analysis identified three independent predictors: post-extubation hypoxemia ( OR  = 14.771, 95% CI : 5.557 ~ 39.268), ASA III ( OR  = 3.924, 95% CI : 1.362 ~ 11.304), and OSAS ( OR  = 3.122, 95% CI :1.091 ~ 8.934). Conclusion ASA III classification, preexisting OSAS, and post-extubation hypoxemia independently predict extended PACU-LOS in patients undergone laparoscopic sleeve gastrectomy. These findings underscore the imperative for preoperative risk stratification using standardized scoring systems, protocolized post-extubation oxygenation strategies, and resource allocation for high-dependency monitoring in at-risk patients.