GLORIOUS: Restrictive versus liberal oxygenation during CPB-assisted surgery

In patients undergoing cardiopulmonary bypass (CPB)-assisted heart surgery, a restrictive oxygenation strategy during CPB and weaning of CPB was not superior to a liberal oxygenation strategy in terms of reducing death, renal failure, stroke, or heart failure.

The single-centre, randomised GLORIOUS trial with a 2-by-2 design tested a restrictive versus a liberal oxygenation strategy as well as the glucagon-like peptide-1 (GLP-1) agonist exenatide versus a placebo among patients who underwent CPB-assisted heart surgery. Dr Sebastian Wiberg (Rigshospitalet Copenhagen University, Denmark) discussed the findings regarding the oxygenation strategy [1]. “Application of CPB is known to cause organ injury,” said Dr Wiberg, “and oxidative stress is part of the mechanism leading to these injuries.”

The trial enrolled 1,389 participants who underwent CPB-assisted coronary artery bypass grafting (CABG) and/or aortic valve replacement. Participants were randomised 1:1 to a restrictive oxygenation strategy (FiO₂ 50%) during CPB and the first hour after weaning from CPB or to a liberal oxygenation strategy (FiO₂ 100%). The primary endpoint was the time to first occurrence of a composite of death, stroke, renal failure, or heart failure. “In case of an oxygen saturation level <92% for more than 30 seconds, FiO₂ was increased to reach a saturation level of at least 92%,” added Dr Wiberg.

As expected, the arterial oxygen partial pressure was significantly higher in the liberal oxygenation arm than in the restricted oxygenation arm (210 mmHg vs 83 mmHg; P<0.001). However, after a median follow-up of 5.9 years, the authors did not see a difference between the 2 strategies with respect to the primary endpoint (HR 1.00; 95% CI 0.81–1.30; P=0.92). Neither did Dr Wiberg and colleagues report significant differences between the study arms regarding the occurrence of adverse events. Surgical site infections were numerically but not significantly higher in the restricted oxygenation arm (3.2% vs 1.6%; P=0.05).

“In adult patients undergoing elective or sub-acute CPB-assisted CABG and/or aortic valve replacement, a restrictive oxygenation strategy during CPB and weaning did not reduce mortality or morbidity from renal failure, stroke, or heart failure, as compared with a liberal oxygenation strategy,” concluded Dr Wiberg.

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   1. Wiberg S, et al. Restrictive vs liberal oxygenation in CPB-assisted heart surgery. LBS.04, AHA Scientific Sessions 2024, 16–18 November, Chicago, USA.

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Posted on 3 February 2025