Optimization of positive end-expiratory pressure in reverse Trendelenburg position during laparoscopic surgery in adult patients

The optimal level of PEEP during laparoscopic surgery without lung injury remains unclear and controversial. We hypothesized that personalized adjustment of positive end-expiratory pressure (PEEP) by best compliance could improve perioperative gas exchange and respiratory biomechanics in adult patients undergoing laparoscopic surgery in the reverse Trendelenburg (RT) position.Objective: The primary objective of the study was to determine the difference in oxygenation between the groups. Secondary objectives were differences in intraoperative dynamics of compliance and driving pressure.Methods. A randomized trial was conducted with patients undergoing laparoscopic cholecystectomy, divided into two groups. In the PEEP titration group (iPEEP), PEEP was adjusted according to best compliance. PEEP titration was performed in 1 cmH2O increments. In control group (PEEP5) we set PEEP of 5 cmH2O. Results. Sixty patients were included in the study. PEEP during pneumoperitoneum (PNP) did not differ between the two groups at 5 minutes and 1 hour after PNP (t2, 5.3±4.58 vs 5.0±0.0 cmH2O, t3 5.93±5.09 vs 5.0±0.0 cmH2O, respectively, both P>0.05) and corresponded with esophageal pressure monitoring. Oxygen saturation (SpO2) levels were comparable throughout surgery. Higher driving pressure (DP) was observed in the iPEEPgroup at 5 minutes post-PNP, but DP values remained within protective limits. Compliance decreased in both groups 5 minutes post-PNP but was lower in the iPEEPgroup. These differences in DP and compliance disappeared one hour after PNP and by the end of surgery. The P/F ratio was significantly higher in the iPEEPgroup compared to the PEEP5 group 1 hour and 24 hours post-surgery (p<0.05), although the iPEEPgroup had higher preoperative P/F values.Conclusions. During laparoscopic cholecystectomy in RT position PEEP 5 is sufficient, but some patients need personalized adjustment. Intraoperative titrated PEEP improved perioperative oxygenation and did not affect on respiratory mechanics. Keywords: PEEP, compliance, oxygenation, laparoscopy, lung protective ventilation.