Inspired Oxygen Concentration During the Re-initiation of Two-Lung Ventilation in Thoracic Surgery: A Post Hoc Analysis of Data From the Multicenter Perioperative Outcomes Group

BACKGROUND: A recent multicenter study suggested that the duration of single-lung ventilation, and not the intensity of the hyperoxia (ie, inspired oxygen fraction) during this period, contributes to the development of postoperative pulmonary complications. However, lung reinflation, at the cessation of single-lung ventilation, is a period of particular susceptibility to hyperoxic injury, and the impact of alveolar hyperoxia during this period on postoperative pulmonary complications has not been specifically assessed. METHODS: Clinical practice surrounding the inspired oxygen fraction at lung reinflation and potential clinical implications of alveolar hyperoxia occurring during this period were assessed in this secondary analysis of data from a multicenter retrospective cohort study. RESULTS: On multivariable logistic regression, average inspired oxygen fraction during the period of lung reinflation was independently associated with postoperative pulmonary complications (adjusted odds ratio [aOR]: 1.14, 95% confidence interval [CI], 1.01–1.29, P = .032; unit: 10% FiO 2 increment). The duration of single-lung ventilation (in hours) also remained significant in this model (aOR: 1.21, 95% CI, 1.03–1.42, P = .020). CONCLUSIONS: The results of this study suggest a unique sensitivity to alveolar hyperoxia at the time of lung reinflation and raise the possibility that restricting the inspired oxygen fraction during lung reinflation could reduce injury and related sequelae. Our findings imply that a 10% increase in FiO 2 during the reinflation period (eg, increasing FiO 2 from 80% to 90%) would be associated with 14% greater odds of developing a postoperative pulmonary complication. However, they should be viewed as hypothesis-generating due to the retrospective nature of the study and serve as justification for prospective investigation of this association.