Can Lactate Clearance Predict Mortality in Critically Ill Children?

Abstract

Serial evaluation of blood lactate, including lactate clearance, may have greater value over single measurement at the time of presentation. The rationale of the current study was to evaluate the use of lactate clearance after 6 hours of admission to pediatric intensive care unit (PICU) as a predictor of mortality in critically ill children. A prospective observational study was conducted in a nine-bed PICU of a tertiary care teaching hospital over a period of 6 months. Lactate levels were measured in arterial blood samples of 76 patients at the time of admission and 6 hours later. According to calculated lactate clearance, patients were divided into group A (lactate clearance more than 0) which included 71% of patients and group B (lactate clearance ≤0) which included 29% of patients. Lactate level at admission was a poor predictor of mortality (area under receiver operating characteristic curve [AUC] = 0.519, p = 0.789). Lactate clearance after 6 hours of admission was a significant predictor of mortality (AUC = 0.766, p < 0.001). Using Kaplan-Meier survival curve, overall survival was significantly better among group A ( p < 0.001). Using multivariate logistic regression model, lactate clearance after 6 hours (odds ratio = 0.98, 95% confidence interval [CI]: 0.96-0.99) and The Pediatric Index of Mortality 2 (PIM2) score (odds ratio = 4.7, 95% CI: 1.85-12.28) had independent prognostic significance with regard to mortality ( p = 0.030, 0.001 respectively). We conclude that lactate clearance after 6 hours of admission can predict mortality in critically ill children.