What question did this study set out to answer?

To investigate the effects of restrictive versus liberal oxygenation strategies on pulmonary function after open-heart surgery.

April 17, 2026Open Access

Impact of Restrictive vs. Liberal Oxygenation on Pulmonary Decline After Open-Heart Surgery: A substudy of the GLORIOUS randomized clinical trial

Key Points

To investigate the effects of restrictive versus liberal oxygenation strategies on pulmonary function after open-heart surgery.
Exploratory substudy of a randomized clinical trial design
Involved adult patients undergoing CABG and/or SAVR
Compared oxygenation strategies of FiO2 50% versus FiO2 100% during CPB and the first postoperative hour
Measured pulmonary function parameters preoperatively and three months postoperatively
Overall pulmonary function declined significantly across all parameters three months post-surgery.
Median FEV declined by 8.3 percentage points and FVC by 6.1 percentage points.
No significant between-group differences in pulmonary decline were observed (all p>0.3).
Findings highlight that neither oxygenation strategy prevented the decline.

Abstract

Objectives Pulmonary dysfunction is a known complication of open-heart surgery.High fractions of inspired oxygen (FiO2) 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 ANONYMOUS randomized, clinical trial.Setting Single tertiary center with cardiothoracic surgery expertise.Participants Adult patients undergoing non-emergent coronary artery bypass grafting (CABG) and/or surgical aortic valve replacement (SAVR).Interventions Restrictive (FiO2 50%) vs. liberal (FiO2 100%) oxygenation during CPB and the first hour after weaning or until patient transfer from the operating table.Pulmonary function (FEV, FVC, FEV/FVC, and DLCO) measured preoperatively and three months postoperatively.Measurements and Main Results A total of 878 patients were included in the study.Postoperatively, at the three months mark, pulmonary function declined across all parameters in the overall study population (median FEV (%predicted) by 8.3 percentage points (95%CI 6.6 to 8.3), FVC (% predicted) by 6.1 pp (95%CI 5.2 to 7.0), FEV/FVC by 1.6 pp (95%CI 1.0 to 2.1), and DLCO (% predicted corrected) by 7.7 pp (95%CI 6.2 to 9.1), (all p0.3), including in subgroup analyses.Conclusions While pulmonary function exhibited a mild-to moderate decline three months after open-heart surgery, a restrictive (FiO2 50%) oxygenation strategy during CPB did not attenuate this decline compared to a liberal (FiO2 100%) strategy.Findings are hypothesisgenerating.

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