Esophageal pressure versus gas exchange to set peep during intraoperative ventilation

Abstract

BACKGROUND: Pneumoperitoneum and Trendelenburg position affect respiratory system mechanics and oxygenation during elective pelvic robotic surgery. The primary aim of this randomized pilot study was to compare the effects of a conventional low tidal volume ventilation with PEEP guided by gas exchange (VGas-guided) versus low tidal volume ventilation tailoring PEEP according to esophageal pressure (VPes-guided) on oxygenation and respiratory mechanics during elective pelvic robotic surgery. METHODS: This study was conducted in a single-center tertiary hospital between September 2017 and January 2019. Forty-nine adult patients scheduled for elective pelvic robotic surgery were screened; 28 subjects completed the full analysis. Exclusion criteria were American Society of Anesthesiologists physical status 6 3, contraindications to nasogastric catheter placement, and pregnancy. After dedicated naso/orogastric catheter insertion, subjects were randomly assigned to VGas-guided (FIO2 and PEEP set to achieve SpO2 > 94%) or VPes-guided (PEEP tailored to equalize end-expiratory transpulmonary pressure). Oxygenation (PaO2 /FIO2 ) was evaluated (1) at randomization, after pneumoperitoneum and Trendelenburg application; (2) at 60 min; (3) at 120 min following randomization; and (4) at end of surgery. Respiratory mechanics were assessed during the duration of the study. RESULTS: Compared to VGas-guided, oxygenation was higher with VPes-guided at 60 min (388 6 90 vs 308 6 95 mm Hg, P 5 .02), at 120 min after randomization (400 6 90 vs 308 6 81 mm Hg, P 5 .008), and at the end of surgery (402 6 95 vs 312 6 95 mm Hg, P 5 .009). Respiratory system elastance was lower with VPes-guided compared to VGas-guided at 20 min (24.2 6 7.3 vs 33.4 6 10.7 cm H2O/L, P 5 .001) and 60 min (24.1 6 5.4 vs 31.9 6 8.5 cm H2O/L, P 5 .006) from randomization. CONCLUSIONS: Oxygenation and respiratory system mechanics were improved when applying a ventilatory strategy tailoring PEEP to equalize expiratory transpulmonary pressure in subjects undergoing pelvic robotic surgery compared to a VGas-guided approach. (ClinicalTrials.gov registration NCT03153592)NCT03153592).