Driving Pressure and Postoperative Pulmonary Complications in Thoracic Surgery

Nowdays, the usual setting of protective ventilation during one lung ventilation is tidal volume (VT) 5 ml/kg of predicted body weight, positive end-expiratory pressure (PEEP) 5 cm H2O and plateau pressure (Pplat) less than 25 cmH2O. However, a high incidence of postoperative pulmonary complications is still being observed even with a protective ventilatory strategy. Driving pressure is \[Pplat - PEEP\] and is the pressure required for the alveolar opening. Static lung compliance (Cstat) is expressed as \[VT / (Pplat - PEEP)\]. Thus, driving pressure is also expressed as \[VT / Cstat\]. Driving pressure has an inverse relationship with Cstat and orthodromic relationship with VT according to this formula. High driving pressure indicates poor lung condition with decreased lung compliance. Thus, investigator try to prove that driving pressure limited ventilation is superior in preventing postoperative pulmonary complications to existing protective ventilation in large scale multicenter study. Recruit maneuver perform all group after intubation (stepwise increase of positive end expiratory pressure 5,10,15 cmH2O with tidal volume 5mL/kg). The control arm receives existing conventional protective ventilation with tidal volume of 5mL/kg of ideal body weight and PEEP of 5 cmH2O during one-lung ventilation. The driving pressure arm receives driving pressure limited ventilation with tidal volume of 5mL/kg of ideal body weight and individualized PEEP. Individualized PEEP is adjusted to minimize driving pressure, it find through decremental PEEP titration from 10 to 2 cmH2O during one-lung ventilation.