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

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 DO2during 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 DO2measurements 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 DO2and increased risk of AKI, intraoperative lactate elevations, and prolonged mechanical ventilation. Five randomized controlled trials (RCTs) demonstrated that maintaining DO2levels, indexed to body surface area (iDO2), above a threshold of 270–300 mL/min/m2significantly reduced the risk of postoperative AKI. However, evidence linking DO2management directly to reductions in mortality or neurologic complications remains limited, as well as studies reporting compliance with GDP strategies. Conclusion: Maintaining adequate iDO2during 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 iDO2threshold 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 DO2threshold determination.