Postoperative pulmonary complications in the ENIGMA II Trial: A post hoc analysis.

Abstract

Nitrous oxide (N2O) promotes absorption atelectasis in poorly ventilated lung segments at high inspired concentrations. The ENIGMA Trial found a higher incidence of postoperative pulmonary complications (PPCs) and wound sepsis with N2O anesthesia in major surgery compared to FIO2 0.8 without N2O. The larger ENIGMA II trial randomised patients to N2O or air at FIO2 0.3 but found no effect on wound infection or sepsis. However, postoperative pulmonary complications were not measured. In the current study we collected post hoc data to determine if atelectasis and pneumonia incidences were higher with N2O in patients who were recruited to the Australian cohort of ENIGMA II.