Association Between Intraoperative Hyperlactatemia and Infection After Cardiac Surgery With Cardiopulmonary Bypass: A Multicenter Retrospective Study

ABSTRACT Objectives To test the hypotheses that intraoperative hyperlactatemia is independently associated with increased postoperative infection risk in cardiac surgery with cardiopulmonary bypass (CPB). Methods This study involved 4970 cardiac surgical patients with CPB from two medical centers. Intraoperative hyperlactatemia was defined as blood lactate levels exceeding 2.0 mmol/L. The main objective was to investigate the association between intraoperative hyperlactatemia and postoperative infections. Furthermore, we identified the threshold values of intraoperative peak blood lactate levels linked to a heightened risk of postoperative infection. Results Postoperative infections occurred in 14.49% of the patients included in the study. Patients who developed postoperative infection had significantly higher intraoperative median peak lactate levels (3.5 mmol/L vs. 2.6 mmol/L and p < 0.001). After adjusting for confounders, patients with intraoperative hyperlactatemia had roughly a 1.5‐fold increased risk of developing postoperative infection (adjusted OR: 1.49; 95% CI: 1.18–1.91; and p < 0.001). Moreover, the threshold for intraoperative peak blood lactate levels that correlated with a higher risk of composite in‐hospital postoperative infection was approximately 2.7 mmol/L. Conclusions Consistent with our hypothesis, intraoperative hyperlactatemia was independently associated with a 1.49‐fold increased risk of postoperative infection in CPB‐assisted cardiac surgery. Notably, maintaining intraoperative blood lactate levels below 2.7 mmol/L might lower the risk of such infections.