Effects of individualized positive end-expiratory pressure combined with recruitment maneuver on intraoperative ventilation during abdominal surgery: a systematic review and network meta-analysis of randomized controlled trials

Abstract

Low tidal volume ventilation strategy may lead to atelectasis without proper positive end-expiratory pressure (PEEP) and recruitment maneuver (RM) settings. RM followed by individualized PEEP was a new method to optimize the intraoperative pulmonary function. We conducted a systematic review and network meta-analysis of randomized clinical trials to compare the effects of individualized PEEP + RM on intraoperative pulmonary function and hemodynamic with other PEEP and RM settings. The primary outcomes were intraoperative oxygenation index and dynamic compliance, while the secondary outcomes were intraoperative heart rate and mean arterial pressure. In total, we identified 15 clinical trials containing 36 randomized groups with 3634 participants. Ventilation strategies were divided into eight groups by four PEEP (L: low, M: moderate, H: high, and I: individualized) and two RM (yes or no) settings. The main results showed that IPEEP + RM group was superior to all other groups regarding to both oxygenation index and dynamic compliance. LPEEP group was inferior to LPEEP + RM, MPEEP, MPEEP + RM, and IPEEP + RM in terms of oxygenation index and LPEEP + RM, MPEEP, MPEEP + RM, HPEEP + RM, IPEEP, and IPEEP + RM in terms of dynamic compliance. All comparisons were similar for secondary outcomes. Our analysis suggested that individualized PEEP and RM may be the optimal low tidal volume ventilation strategy at present, while low PEEP without RM is not suggested.

Keywords: Abdominal surgery; Alveolar recruitment maneuver; Individualized; Network meta-analysis; Positive end-expiratory pressure; Protective lung strategy.

Fig. 1

PRISMA flow diagram. RCT randomized controlled trial, PRISMA Preferred Reporting Items for Systematic Reviews and Meta-Analyses

Fig. 2

Risk-of-bias assessment of included studies

Fig. 3

Network plot of enrolled studies in this network meta-analysis. a Oxygenation index; b dynamic compliance; c mean arterial pressure; d heart rate; LPEEP low PEEP, MPEEP moderate PEEP, HPEEP high PEEP, IPEEP individualized PEEP, RM recruitment maneuver

Fig. 4

Comparison-adjusted funnel plot for intraoperative oxygenation index. LPEEP low PEEP, MPEEP moderate PEEP, HPEEP high PEEP, IPEEP individualized PEEP, RM recruitment maneuver

Fig. 5

Comparison-adjusted funnel plot for intraoperative dynamic compliance. LPEEP low PEEP, MPEEP moderate PEEP, HPEEP high PEEP, IPEEP individualized PEEP, RM recruitment maneuver