Positive end-expiratory pressure setting based on transpulmonary pressure during robot-assisted laparoscopic...

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 (rSO₂), and hemodynamics.

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 cmH₂O (5 cmH₂O per increase) every 30 min. PEEP levels were assessed where end-expiratory Ptp levels of ≥0 cmH₂O were achieved (PtpEEP0). Airway pressure, esophageal pressure, cardiac index, and blood gas and rSO₂ values were measured after 30 min at each PEEP step and respiratory mechanics were calculated.

With increasing PEEP levels from 0 to 15 cmH₂O or PtpEEP0, the values of PaO₂ and respiratory system compliance increased, and the values of driving pressure decreased. The median PEEP level associated with PtpEEP0 was 15 cmH₂O. 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 rSO₂ were higher at PtpEEP0 than at PEEP0 (right; P = 0.0019, left; P = 0.036).

PEEP setting determined by transpulmonary pressure can help achieve higher respiratory system compliance values and lower driving pressure without disturbing hemodynamic parameters.