Delivery of oxygen during cardiopulmonary bypass and associated clinical outcomes among adult cardiac surgery patients: A systematic review

Abstract

Purpose

Oxygen delivery (DO₂) during cardiopulmonary bypass (CPB) is critical in preventing postoperative complications in adult cardiac surgery. This systematic review aimed to assess the relationship between intraoperative DO₂ during CPB, particularly within Goal-directed Perfusion (GDP) strategies, and associated clinical outcomes.

Methods

A systematic search of MEDLINE, Embase, Web of Science, PsycINFO, CINAHL, PROSPERO, and Cochrane was conducted from database inception through December 2024, adhering to PRISMA 2020 guidelines. Studies reported intraoperative DO₂ measurements and their relationship with clinical outcomes among adults undergoing cardiac surgery with CPB. Data extraction and quality assessment were performed independently by two reviewers.

Results

Thirty-nine studies (71,050 patients) were included, with acute kidney injury (AKI) being the most frequently studied outcome (84.6% of studies). A consistent association was found between lower intraoperative DO₂ and increased risk of AKI, intraoperative lactate elevations, and prolonged mechanical ventilation. Five randomized controlled trials (RCTs) demonstrated that maintaining DO₂ levels, indexed to body surface area (iDO₂), above a threshold of 270–300 mL/min/m² significantly reduced the risk of postoperative AKI. However, evidence linking DO₂ management directly to reductions in mortality or neurologic complications remains limited, as well as studies reporting compliance with GDP strategies.

Conclusion

Maintaining adequate iDO₂ during CPB significantly reduces postoperative complications, especially AKI. These findings underscore the clinical relevance of GDP strategies, highlighting the importance of individualized perfusion management to optimize outcomes. Further large-scale RCTs are needed to confirm these benefits, standardize specific iDO₂ threshold levels that are beneficial, and to explore strategies that impact mortality and neurologic outcomes, as well as investigate the role that temperature management plays in DO₂ threshold determination.