Impact of Restrictive Versus Liberal Oxygenation on Pulmonary Decline After Cardiac Surgery: A Substudy of the GLORIOUS Randomized Clinical Trial

OBJECTIVES: ) during the critical pulmonary reperfusion phase of cardiopulmonary bypass (CPB) weaning is a proposed pathophysiological contributor yet remains sparsely investigated. DESIGN: Predefined, exploratory substudy of the GLORIOUS randomized, clinical trial. SETTING: Single tertiary center with cardiothoracic surgery expertise. PARTICIPANTS: Adult patients undergoing nonemergent coronary artery bypass grafting (CABG) and/or surgical aortic valve replacement. INTERVENTIONS: 100%) oxygenation during CPB and the first hour after weaning or until patient transfer from the operating table. Pulmonary function (forced expired volume in 1 second [FEV₁], forced vital capacity [FVC], FEV₁/FVC, and diffusion capacity of carbon monoxide) was measured preoperatively and 3 months postoperatively. MEASUREMENTS AND MAIN RESULTS: A total of 878 patients were included in the study. Postoperatively, at the 3-month mark, pulmonary function declined across all parameters in the overall study population (median FEV₁ [% predicted] by 8.3 percentage points [95% CI 6.6 to 8.3], FVC [% predicted] by 6.1 percentage points [95% CI 5.2 to 7.0], FEV₁/FVC by 1.6 percentage points [95% CI 1.0 to 2.1], and diffusion capacity of carbon monoxide [% predicted corrected] by 7.7 percentage points [95% CI 6.2 to 9.1], all p< 0.001). However, no significant between-group differences in decline were observed (all p > 0.3), including in subgroup analyses. CONCLUSIONS: 100%) strategy. Findings are hypothesis-generating.