Recruitable alveolar collapse and overdistension during laparoscopic gynecological surgery and mechanical ventilation: a prospective clinical study
Laparoscopic surgery in Trendelenburg position may impede mechanical ventilation (MV) due to positioning and high intra-abdominal pressure. We sought to identify the positive end-expiratory pressure (PEEP) levels necessary to counteract atelectasis formation ("Open-Lung-PEEP") and to provide an equal balance between overdistension and alveolar collapse ("Best-Compromise-PEEP").
In supine position, the median Open-Lung-PEEP was 12 (8-14) cmH2O with 8.7 (4.7-15.5)% of overdistension and 1.7 (0.4-2.2)% of collapse. Best-Compromise-PEEP was 8 (6.5-10) cmH2O with 4.2 (2.4-7.2)% of overdistension and 5.1 (3.9-6.5)% of collapse. In Trendelenburg position with capnoperitoneum, Open-Lung-PEEP was 18 (18-20) cmH 2 O (p < 0.0001 vs supine position) with 1.8 (0.5-3.9)% of overdistension and 0 (0-1.2)% of collapse and Best-Compromise-PEEP was 18 (16-20) cmH2O (p < 0.0001 vs supine position) with 1.5 (0.7-3.0)% of overdistension and 0.2 (0-2.7)% of collapse. Open-Lung-PEEP and Best-Compromise-PEEP were positively correlated with body mass index during MV in supine position but not in Trendelenburg position.
The PEEP levels required for preventing alveolar collapse and for balancing collapse and overdistension in Trendelenburg position with capnoperitoneum were significantly higher than those required for achieving the same goals in supine position without capnoperitoneum. Even with high PEEP levels, alveolar overdistension was negligible during MV in Trendelenburg position with capnoperitoneum.
This study was prospectively registered at German Clinical Trials registry (DRKS00016974).