Individualised Positive End-Expiratory Pressure During Robotic-Assisted Radical Prostatectomy Guided by Intratidal Compliance-Volume Curve Analysis.

Abstract

Steep Trendelenburg positioning and capnoperitoneum during robotic-assisted prostatectomy adversely affect respiratory system mechanics and decrease dorsal lung ventilation. We hypothesised that individualising positive end-expiratory pressure (PEEP) based on intratidal compliance-volume curve analysis enhances dorsal regional lung ventilation. Thirty male patients undergoing robotic-assisted prostatectomy received a tidal volume of 7 mL kg^-1 and a PEEP of 7 cmH₂O. PEEP was increased in steps of 3 cmH₂O until a predominance of horizontal intratidal compliance profiles occurred or a PEEP of 22 cmH₂O was reached. The primary endpoint was the share of dorsal lung ventilation. Secondary endpoints included respiratory system mechanics, oxygenation, and haemodynamics. Best PEEP was 20.6 ± 2.7 cmH₂O. At best PEEP, defined as a predominance of horizontal intratidal compliance profiles, the share of dorsal ventilation was increased by 41% compared with PEEP 7 cmH₂O (p < 0.001) and oxygenation improved [P_aO₂/F_iO₂ 417 mmHg (95% CI 387-446) vs. 400 mmHg (95% CI 365-436), p = 0.016]. Aside from a slight increase in norepinephrine dosage [0.054 μg kg^-1 min^-1 (95% CI 0.043-0.066) vs. 0.048 μg kg^-1 (95% CI 0.037-0.059), p = 0.01], haemodynamic parameters were not affected by PEEP. Individualised PEEP guided by intratidal compliance-volume curve analysis enhanced dorsal lung ventilation, reduced driving pressure, and improved oxygenation during robotic-assisted prostatectomy. DRKS00021009 (ClinicalTrials.gov identifier: DRKS00021009).