Effects of Positive Airway Pressure and Mechanical Ventilation of the Lungs During Cardiopulmonary Bypass on Pulmonary Adverse Events After Cardiac Surgery: A Systematic Review and Meta-Analysis

CPAP during CPB improved the alveolar-arterial oxygen gradient difference compared with apnea, but ventilation during CPB did not. Neither CPAP nor ventilation during CPB demonstrated evidence of improving clinical outcomes in low- or intermediate-risk patients for elective cardiac surgery. The findings are inconclusive because of heterogeneity and small sample sizes.