Comparison of the effects of PEEP levels on respiratory mechanics and elimination of volatile anesthetic agents in patients undergoing laparoscopic cholecystectomy; a prospective, randomized, clinical trial.

BACKGROUND/AIM In laparoscopic procedures, intraabdominal carbon dioxide (CO2) insufflation can cause decreased compliance, increased airway resistance, and impaired ventilation-perfusion ratios. We aimed to investigate the effects of intraoperative positive end-expiratory pressure (PEEP) treatment on respiratory dynamics and elimination time of volatile anesthetic agents. MATERIALS AND METHODS In the present study, 75 ASA I-II patients were randomized into 3 groups to receive 0 cmH2O PEEP (group I), 5 cmH2O PEEP (group II), or 8 cmH2O PEEP (group III). Hemodynamic parameters, peak and plateau inspiratory airway pressures (Ppeak, Pplateau), compliance values, the ratio of the fractions of inspired and expired concentration of sevoflurane (Fi/Fexp sevoflurane) at 1 MAC, times from 1 to 0.3 and 0.1 MAC and values for pulmonary function tests (PFT) were recorded. RESULTS Ppeak and Pplateau in group III were higher; compliance values in group I and the extent of reduction in postoperative forced vital capacity (FVC) in group III were lower than those in the other groups (P < 0.05). No significant difference was observed between the groups regarding times from 1 to 0.3 MAC and times from 0.3 to 0.1 MAC. CONCLUSION It was found that 8 cmH2O PEEP increased compliance without clinically significant pulmonary deterioration and that 8 cmH2O PEEP led to less impairment in postoperative PFTs compared to 0 and 5 cmH2O PEEP but had no effect on sevoflurane elimination time.