Metabolic acidosis as a predictor of outcome in critically ill children – A single-center prospective observational study

Abstract

Background: Acid-base disorders are common in critically ill patients and contribute significantly to mortality and morbidity. Metabolic acidosis (MA) can be measured by pH, base deficit, serum bicarbonate, and anion gap. A study was conducted to determine the incidence and type of MA among children admitted to the pediatric intensive care unit (PICU) and to assess its roles as a predictor of outcomes in them. Subjects and Methods: Over 1 year, 100 children between 1 month and 12 years of age who presented to the PICU with an MA or developed it within 24 h of admission were prospectively enrolled. Clinicodemographic data, pediatric sequential organ failure assessment score at admission, clinical outcome, and serial measurements of anion gap, serum lactate, and bicarbonate level were recorded. Results: The incidence of MA was 60.2% with a majority (52%) being high anion gap metabolic acidosis (HAGMA). The predominant condition (39%) leading to MA was catecholamine-resistant shock with organ dysfunction. Peak lactate value and bicarbonate nadir had a significant positive correlation with the duration of mechanical ventilation and inotropic support, but only peak lactate value was significantly associated with mortality. A peak lactate value of 2.19 mmol/L yielded the highest sensitivity and specificity for predicting mortality. There was no association was found between peak anion gap and morbidity or mortality. Conclusions: MA was observed in 60% of children in PICU, with HAGMA being the most common type. Peak lactate value and bicarbonate nadir were correlated with high morbidity, but only peak lactate value was significantly associated with mortality.