Severity of illness correlates with alterations in energy metabolism in the pediatric intensive care unit.

Abstract

To evaluate the correlations between severity of illness scoring systems and biochemical markers of physiologic stress. Tertiary care pediatric ICU in a university hospital. A prospective, clinical study. Twelve patients aged 2 to 120 months (four patients aged less than 12 months) with varying diagnoses including sepsis, cardiovascular surgery, respiratory failure. Oxygen consumption (VO2), daily total urinary nitrogen, and the branch chain to aromatic amino acid ratio were correlated with the Physiologic Stability Index, Pediatric Risk of Mortality score, and Therapeutic Intervention Scoring System. Linear regression analysis and multivariate stepwise regression analysis were used to analyze the data. Pediatric Risk of Mortality score and Physiologic Stability Index correlated with VO2 (r2 = .69, p less than .001 and r2 = .52, p less than .01, respectively) and with daily total urinary nitrogen excretion (r2 = .66, p less than .001 and r2 = .62, p less than .01, respectively). The Therapeutic Intervention Scoring System correlated with the total urinary nitrogen excretion (r2 = .69, p less than .001) and branch chain to aromatic amino acid ratio (r2 = .49, p less than .01). Correlations existed between Pediatric Risk of Mortality score and Physiologic Stability Index (r2 = .88, p less than .001) and Pediatric Risk of Mortality score and Therapeutic Intervention Scoring System (r2 = .48, p less than .01). The correlations were independent of diagnostic category, suggesting that the alterations in biochemical variables were most directly related to the overall severity of illness as measured by the scoring system.