Lactate clearance as a predictor of mortality in critically ill children – A single center prospective observational study

Background: Hyperlactatemia is a common finding in critically ill children and has a strong association with mortality. Lactate clearance (LC) correlates better with mortality than single-point estimation of lactate. This study aimed to evaluate the prognostic value of LC in predicting mortality among children in the intensive care unit (ICU). Subjects and Methods: In this prospective study from the tertiary pediatric ICU of a teaching hospital in India, 150 children aged 1 month to 17 years were included. Serial blood lactate levels were measured at admission, 12 h, 24 h, and 48 h. LC was calculated at 12, 24, and 48 h. Results: The median age (interquartile range [IQR]) of the study population was 2 (8.7) years. Thirty-two patients (21.3%) died. LC of < 10% at 24 h (area under the receiver operating characteristic curve [AUC]: 0.786) and <23% at 48 h (AUC: 0.827) provided the best sensitivity and specificity for predicting mortality as compared to 12 h clearance (AUC: 0.572). Although admission lactate in nonsurvivors (median [IQR]: 41.5 [21.4]) was higher than in survivors (median [IQR]: 29 [17.15]), the difference was not statistically significant ( P = 0.061). Serial lactate estimation showed a statistically significant difference between survivors and nonsurvivors at 12 h (<0.001), 24 h (<0.001), and 48 h (<0.001). Lactate at 24 h (AUC: 0.849) and 48 h (AUC: 0.895) had better predictive value than at admission lactate (AUC: 0.591). Conclusions: LC is a fair predictor of mortality among children in the ICU. Delayed LC at 24 h and 48 h predicted mortality better than at 12 h.