Serum anion gap versus lactate clearance as mortality predictors in critically ill children

Introduction: Mortality prediction is important for optimal resource allocation in the paediatric intensive care unit (PICU).
Objectives: To estimate the predictive value of serum corrected anion gap (cAG) and lactate clearance for predicting mortality in PICU.   
Method: We conducted a prospective study of children admitted to the PICU of a tertiary hospital. PRISM III and IV score, cAG and lactate clearance were done in all patients, and the predictive value was calculated for mortality.     
Results: The mortality in the study group was 12%. The cAG was significantly lower in survivors than in non-survivors (p <0.001). The lactate levels at 6 hours (AUC 0.898) had the best mortality prediction, followed by admission lactate (AUC 0.804) and cAG (AUC 0.742). However, the lactate clearance did not show good predictive value.  
Conclusions: The cAG is an excellent mortality predictor in a low-resource setting.