Evaluation of Increase in Intraoperative Lactate Level as a Predictor of Outcome in Adults After Cardiac Surgery.

OBJECTIVES: Early onset hyperlactatemia develops intraoperatively or within the first 6 hours of admission to the intensive care unit (ICU) and is associated with a poor prognosis. The aim of the present study was to determine the utility of an increase in the intraoperative lactate level, independent of the absolute lactate value at baseline after induction, as a dynamic parameter for morbidity (ICU length of stay, postoperative renal failure, and inotrope use) and mortality in adults post-cardiac surgery. DESIGN: Retrospective observational study. SETTING: Single-center study in an academic hospital. PARTICIPANTS: The study comprised 779 patients who underwent elective cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were classified into the following 5 groups based on the increase in the intraoperative lactate level: (1) group 1-negative, (2) group 2-1- to 1.59-fold increase, (3) group 3-1.6- to 1.99-fold increase, (4) group 4-2- to 3-fold increase, and (5) group 5->3-fold increase. Logistic regression analyses were performed. Group 5 had a 4 times greater mortality (7.7%), the longest ICU length of stay (89.02 ± 78.73 h), and the greatest incidence of postoperative renal failure (n = 5 [19.2%]) compared with group 1. The increase in the intraoperative lactate level was a statistically significant predictor of mortality (p = 0.001) and ICU length of hospital stay (p = 0.0006) and was highly predictive for postoperative renal failure requiring renal replacement therapy (p = 0.001). CONCLUSIONS: An increase in intraoperative lactate, independent of the level on induction, is a useful dynamic parameter to identify patients at risk of postoperative morbidity and mortality and might provide an early trigger for introducing measures to avoid poor outcomes.