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BackgroundThere is limited information concerning the current practice of intraoperative mechanical ventilation in obese patients, and the optimal ventilator settings for these patients are debated. We investigated intraoperative ventilation parameters and their associations with the development of postoperative pulmonary complications (PPCs) in obese patients.MethodsWe performed a secondary analysis of the international multicentre Local ASsessment of VEntilatory management during General Anesthesia for Surgery' (LAS VEGAS) study, restricted to obese patients, with a predefined composite outcome of PPCs as primary end-point.ResultsWe analysed 2012 obese patients from 135 hospitals across 29 countries in Europe, North America, North Africa, and the Middle East. Tidal volume was 8.8 [25th-75th percentiles: 7.8-9.9] ml kg-1 predicted body weight, PEEP was 4 [1-5] cm H2O, and recruitment manoeuvres were performed in 7.7% of patients. PPCs occurred in 11.7% of patients and were independently associated with age (P<0.001), body mass index ≥40 kg m-2 (P=0.033), obstructive sleep apnoea (P=0.002), duration of anaesthesia (P<0.001), peak airway pressure (P<0.001), use of rescue recruitment manoeuvres (P<0.05) and routine recruitment manoeuvres performed by bag squeezing (P=0.021). PPCs were associated with an increased length of hospital stay (P<0.001).ConclusionsObese patients are frequently ventilated with high tidal volume and low PEEP, and seldom receive recruitment manoeuvres. PPCs increase hospital stay, and are associated with preoperative conditions, duration of anaesthesia and intraoperative ventilation settings. Randomised trials are warranted to clarify the role of different ventilatory parameters in obese patients.Clinical trial registrationNCT01601223.

Original publication




Journal article


British journal of anaesthesia

Publication Date





899 - 908


Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Policlinico San Martino, Genova, Italy; Department of Intensive Care, Amsterdam, The Netherlands. Electronic address:


LAS VEGAS investigators, PROVE Network, Clinical Trial Network of the European Society of Anaesthesiology, Humans, Lung Diseases, Sleep Apnea Syndromes, Obesity, Postoperative Complications, Body Weight, Tidal Volume, Body Mass Index, Respiration, Artificial, Length of Stay, Positive-Pressure Respiration, Anesthesia, General, Kaplan-Meier Estimate