Intraoperative ventilation: incidence and risk factors for receiving large tidal volumes during general anesthesia

We performed a cross-sectional analysis of our prospectively collected perioperative electronic database for current intraoperative ventilation practices and risk factors for receiving large tidal volumes (VT > 10 mL/kg PBW). We included all adults undergoing prolonged (≥ 4 h) elective abdominal surgery and collected demographic, preoperative (comorbidities), intraoperative (i.e. ventilatory settings, fluid administration) and postoperative (outcomes) information. We compared patients receiving exhaled tidal volumes > 10 mL/kg PBW with those that received 8-10 or < 8 mL/kg PBW with univariate and logistic regression analyses.Ventilatory settings were non-uniform in the 429 adults included in the analysis. 17.5% of all patients received VT > 10 mL/kg PBW. 34.0% of all obese patients (body mass index, BMI, ≥ 30), 51% of all patients with a height < 165 cm, and 34.6% of all female patients received VT > 10 mL/kg PBW.Ventilation with VT > 10 mL/kg PBW is still common, although poor correlation with PBW suggests it may be unintentional. BMI ≥ 30, female gender and height < 165 cm may predispose to receive large tidal volumes during general anesthesia. Further awareness of patients' height and PBW is needed to improve intraoperative ventilation practices. The impact on clinical outcome needs confirmation.The lung can be injured by positive pressure ventilation. Mechanical stretch triggers a proinflammatory response within the first 2 hours in healthy animal models [1-4]. The benefit of lung protective ventilation (LPV) with low tidal volumes (VT), usually 6 mL/kg predicted body weight (PBW), has been strongly evidenced for patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS) [5-8]. LPV strategies, designed to limit end-inspiratory volumes and pressures, were associated with reduced inflammatory markers in bronchoalveolar lavage fluid and blood [6-8] and improved clinical outcomes [5,7,8].In patients without evidence of existing lung injury, t