Positive end-expiratory pressure setting based on transpulmonary pressure during robot-assisted laparoscopic prostatectomy: an observational intervention study

Abstract

Abstract Background In robot-assisted laparoscopic prostatectomy (RALP), concerns include the formation of atelectasis and reduced functional residual capacity. The present study aimed to examine the feasibility of positive end-expiratory pressure (PEEP) setting based on transpulmonary pressure (Ptp) as well as the effects of incremental PEEP on respiratory mechanics, blood gases, cerebral oxygenation (rSO 2 ), and hemodynamics. Methods Fourteen male patients who were scheduled to receive RALP were recruited. Patients received mechanical ventilation (tidal volume of 6 mL kg −1 ) and were placed in Trendelenburg position with positive-pressure capnoperitoneum. PEEP levels were increased from 0 to 15 cmH 2 O (5 cmH 2 O per increase) every 30 min. PEEP levels were assessed where end-expiratory Ptp levels of ≥0 cmH 2 O were achieved (PtpEEP0). Airway pressure, esophageal pressure, cardiac index, and blood gas and rSO 2 values were measured after 30 min at each PEEP step and respiratory mechanics were calculated. Results With increasing PEEP levels from 0 to 15 cmH 2 O or PtpEEP0, the values of PaO 2 and respiratory system compliance increased, and the values of driving pressure decreased. The median PEEP level associated with PtpEEP0 was 15 cmH 2 O. Respiratory system compliance values were higher at PtpEEP0 than those at PEEP5 ( P = 0.02). Driving pressure was significantly lower at PtpEEP0 than at PEEP5 ( P = 0.0036). The cardiac index remained unchanged, and the values of rSO 2 were higher at PtpEEP0 than at PEEP0 (right; P = 0.0019, left; P = 0.036). Conclusions PEEP setting determined by transpulmonary pressure can help achieve higher respiratory system compliance values and lower driving pressure without disturbing hemodynamic parameters.