Exploring the intraoperative lung protective ventilation of different positive end-expiratory pressure levels during abdominal laparoscopic surgery with Trendelenburg position.

Abstract

The intraoperative lung protective effect of mechanical ventilation of different positive end-expiratory pressure (PEEP) levels on patients undergoing abdominal laparoscopic surgery with the steep Trendelenburg position remains undefined. The purpose of the study was to explore the optimal PEEP. Sixty patients scheduled for abdominal laparoscopic surgery were randomized to four groups including: PEEP 0, 4, 8 and 12 cmH2O. The pulmonary dynamic compliance (Cdyn), dead space to tidal volume ratio (VD/VT), and intrapulmonary shunt ratio (QS/QT) were measured after anesthesia induction (T0), 5 min after pneumoperitoneum (PNP) with position change (T1), 30 (T2) and 60 min (T3) after PEEP, and end of surgery (T4). Cdyn increased when different levels of PEEP (including the 4, 8, and 12 cmH2O) were used vs. no PEEP (P<0.05). The VD/VT in PEEP 8 and 12 cmH2O were significantly improved than no PEEP (P<0.05). Meanwhile, the QS/QT in PEEP 12 cmH2O was higher than others during the procedures. A moderate PEEP level (8 cmH2O) with low tidal volume was sufficient to improve Cdyn and to decrease VD/VT without increasing QS/QT, which was suggested to be a good choice of intraoperative lung protective ventilation during abdominal laparoscopic surgery with Trendelenburg position.