Safety and effectiveness of alveolar recruitment maneuvers and positive end-expiratory pressure during general anesthesia for cesarean section: a prospective, randomized trial

Introduction: During cesarean section, the supine position reduces functional residual capacity and worsens lung compliance. We tested the hypothesis that alveolar recruitment maneuvers and positive end-expiratory pressure improve lung compliance in women undergoing general anesthesia for cesarean section. Methods: Ninety women undergoing cesarean section were randomly assigned to one of two groups in a prospective, double-blind trial. In the alveolar recruitment maneuver group, pressure-control ventilation was used and inspiratory time was increased to 50% after delivery; positive end-expiratory pressure was increased to 20 cmH(2)O and peak airway inspiratory pressure gradually increased to 45-50 cmH(2)O. Volume-control ventilation was then used with low tidal volumes (6 mL/kg) and positive end-expiratory pressure was reduced stepwise to 8 cmH(2)O. In the control group, alveolar recruitment maneuvers were not used. Data were collected before and 3, 10 and 20 min after the alveolar recruitment maneuver, before extubation and postoperatively at 10 and 20 min. Results: Dynamic compliance, peak airway inspiratory pressure, PaO2 and PaO2/FiO(2) were significantly different in the alveolar recruitment maneuver group compared to controls at all time points during surgery except at baseline. Oxygen saturation was significantly greater in the alveolar recruitment maneuver group at 10 and 20 min and before extubation. Dynamic compliance was 29.7-42.5% higher and peak airway inspiratory pressure 3.6-10.2% lower in the alveolar recruitment maneuver group compared to controls. The PaO2, PaO2/FiO(2) and oxygen saturation were higher (9.4-12%, 10.3-11.9% and 0.4-1.3%, respectively) in the alveolar recruitment maneuver group. Postoperatively, PaO2 and oxygen saturation were significantly higher in the alveolar recruitment maneuver group compared to controls (PaO2 9.2% at 10 min and 8.4% at 20 min, oxygen saturation 0.8% at 10 min and 1.1% at 20 min). There were no significant differences in hemodynamic stability or adverse events between groups. Conclusion: Compared to standard care, the alveolar recruitment maneuver with positive end-expiratory pressure and low tidal volumes appears safe and effective in improving lung compliance and both intraoperative and postoperative oxygenation in women undergoing general anesthesia for elective cesarean section. (C) 2016 Elsevier Ltd. All rights reserved.