Esophageal Pressure Versus Gas Exchange to Set PEEP During Intraoperative Ventilation.

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 (V) versus low tidal volume ventilation tailoring PEEP according to esophageal pressure (V) 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 ≥ 3, contraindications to nasogastric catheter placement, and pregnancy. After dedicated naso/orogastric catheter insertion, subjects were randomly assigned to V ([Formula: see text] and PEEP set to achieve [Formula: see text] > 94%) or V (PEEP tailored to equalize end-expiratory transpulmonary pressure). Oxygenation ([Formula: see text]/[Formula: see text]) 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 V, oxygenation was higher with V at 60 min (388 ± 90 vs 308 ± 95 mm Hg, = .02), at 120 min after randomization (400 ± 90 vs 308 ± 81 mm Hg, = .008), and at the end of surgery (402 ± 95 vs 312 ± 95 mm Hg, = .009). Respiratory system elastance was lower with V compared to V at 20 min (24.2 ± 7.3 vs 33.4 ± 10.7 cm HO/L, = .001) and 60 min (24.1 ± 5.4 vs 31.9 ± 8.5 cm HO/L, = .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 V approach. (ClinicalTrials.gov registration NCT03153592).