Effects of Recruitment Maneuver and Positive End-Expiratory Pressure on Respiratory Mechanics and Transpulmonary Pressure During Laparoscopic Surgery

Background: The authors tested the hypothesis that during laparoscopic surgery, Trendelenburg position and pneumoperitoneum may worsen chest wall elastance, concomitantly decreasing transpulmonary pressure, and that a protective ventilator strategy applied after pneumoperitoneum induction, by increasing transpulmonary pressure, would result in alveolar recruitment and improvement in respiratory mechanics and gas exchange. Methods: In 29 consecutive patients, a recruiting maneuver followed by positive end-expiratory pressure 5 cm H 2 O maintained until the end of surgery was applied after pneumoperitoneum induction. Respiratory mechanics, gas exchange, blood pressure, and cardiac index were measured before (T BSL ) and after pneumoperitoneum with zero positive end-expiratory pressure (T preOLS ), after recruitment with positive end-expiratory pressure (T postOLS ), and after peritoneum desufflation with positive end-expiratory pressure (T end ). Results: Esophageal pressure was used for partitioning respiratory mechanics between lung and chest wall (data are mean ± SD): on T preOLS , chest wall elastance (E cw ) and elastance of the lung (E L ) increased (8.2 ± 0.9 vs. 6.2 ± 1.2 cm H 2 O/L, respectively, on T BSL ; P = 0.00016; and 11.69 ± 1.68 vs. 9.61 ± 1.52 cm H 2 O/L on T BSL ; P = 0.0007). On T postOLS ,