Association of hypoxemia during one-lung ventilation and postoperative complications: A retrospective cohort study

Intraoperative hypoxemia is a frequent complication during one-lung ventilation (OLV) and may contribute to postoperative morbidity. Although hypoxemic events are often transient, their cumulative physiological impact remains poorly understood. This study evaluated the association between cumulative hypoxemia during OLV and postoperative pulmonary complications in patients undergoing lung surgery.

We conducted a retrospective cohort study of adult patients (≥18 years) who underwent thoracic surgery with OLV between January 2017 and February 2022. Cumulative hypoxemic burden was calculated as the area under the curve (AUC) below a peripheral oxygen saturation (SpO₂) of 90% using trapezoidal integration. The primary outcome was a composite of severe pulmonary complications, including reintubation, prolonged mechanical ventilation, acute respiratory distress syndrome, extended non-invasive ventilatory support, and pneumonia. Multivariable logistic regression analysis was used to assess associations with outcomes, adjusting for potential confounders based on univariate analysis and biological plausibility.

A total of 2748 patients were included in this cohort, of which 60% underwent lung wedge resections, 25% lobectomies, and 14% segmentectomies. The incidence of severe pulmonary complications was 2.5%. In multivariable analysis adjusting for confounders, AUC of SpO₂ < 90% was independently associated with the composite outcome with an estimated odds ratio (OR) of 1.21 (95% confidence interval [CI] 1.02-1.44) per 1% x hour increase in AUC. There was no significant association between AUC of hypoxemia and secondary outcomes such as acute kidney injury (OR 1.14, 95%CI 0.96-1.36, P = 0.130), atrial fibrillation (OR 0.94, 95%CI 0.71-1.25, P = 0.680), delirium (OR 1.10, 95%CI 0.82-1.48, P = 0.523), and five-year all-cause mortality (hazard ratio 0.95, 95%CI 0.77-1.17, P = 0.620).

Cumulative hypoxemia during OLV is independently associated with increased risk of severe postoperative pulmonary complications. Prolonged hypoxemia (≥30 min) may be clinically significant and portend pulmonary complications. Further studies are warranted to explore features mediating this association.