Suleiman et al.1 assert that driving pressure and mechanical power (because of increased respiratory rate in low tidal volume groups) may be more important determinants of perioperative lung injury and postoperative pulmonary complications than tidal volume and positive end-expiratory pressure (PEEP). We used a factorial cluster design to assign 2,860 patients to four combinations of tidal volume and PEEP. There were no differences in oxygenation during recovery or in pulmonary complications among the groups. We therefore concluded that any combinations of tidal volume between 6 and 10 ml/kg and PEEP between 5 and 8 cm H2O are comparably safe in relatively healthy patients having general anesthesia for orthopedic surgery.2
As expected, both driving pressure and mechanical power differed among our four treatment groups (table 1). For example, mechanical power increased approximately 1.2 J/min with each increase in tidal volume and/or PEEP, ranging from...
