title: Safety and effectiveness of alveolar recruitment maneuvers and positive end-expiratory pressure during general anesthesia for cesarean section: a prospective, randomized trial.
abstract: BACKGROUND
  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 20cmH2O and peak airway inspiratory pressure gradually increased to 45-50cmH2O. Volume-control ventilation was then used with low tidal volumes (6mL/kg) and positive end-expiratory pressure was reduced stepwise to 8cmH2O. In the control group, alveolar recruitment maneuvers were not used. Data were collected before and 3, 10 and 20min after the alveolar recruitment maneuver, before extubation and postoperatively at 10 and 20min.
  
  
  RESULTS
  Dynamic compliance, peak airway inspiratory pressure, PaO2and PaO2/FiO2were 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 20min 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/FiO2and oxygen saturation were higher (9.4-12%, 10.3-11.9% and 0.4-1.3%, respectively) in the alveolar recruitment maneuver group. Postoperatively, PaO2and oxygen saturation were significantly higher in the alveolar recruitment maneuver group compared to controls (PaO29.2% at 10min and 8.4% at 20min, oxygen saturation 0.8% at 10min and 1.1% at 20min). There were no significant differences in hemodynamic stability or adverse events between groups.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, School of Medicine, University Hospital of Patras, Rion-Patras, Greece. Electronic address: adaretha@yahoo.gr.
authors.forename: D
authors.initials: D
authors.lastname: Aretha
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, School of Medicine, University Hospital of Patras, Rion-Patras, Greece.
authors.forename: F
authors.initials: F
authors.lastname: Fligou
authors.affiliation: Technological Educational Institute of Western Greece, Patras, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Kiekkas
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, University Hospital of Larissa, Larissa, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Messini
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, School of Medicine, University Hospital of Patras, Rion-Patras, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Panteli
authors.affiliation: Department of Biometrics and Biomathematics, School of Medicine, University of Larissa, Larissa, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Zintzaras
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: M
authors.initials: M
authors.lastname: Karanikolas
mesh_terms: D000328:Adult; D000768:Anesthesia, General / Q000009:adverse effects / Q000379:methods*; D000773:Anesthesia, Obstetrical / Q000009:adverse effects / Q000379:methods*; D002585:Cesarean Section / Q000009:adverse effects / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008170:Lung Compliance; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration; D011247:Pregnancy; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Alveolar recruitment maneuver; Cesarean section; General anesthesia; Lung compliance