Relationships among biochemical measures in children with diabetic ketoacidosis.

OBJECTIVES: Investigating empirical relationships among laboratory measures in children with diabetic ketoacidosis (DKA) can provide insights into physiological alterations occurring during DKA. We determined whether alterations in laboratory measures during DKA conform to theoretical predictions. METHODS: We used Pearson correlation statistics and linear regression to investigate correlations between blood glucose, electrolytes, pH and PCO2 at emergency department presentation in 1,681 pediatric DKA episodes. Among children with repeat DKA episodes, we also assessed correlations between laboratory measures at the first vs. second episode. RESULTS: pH and bicarbonate levels were strongly correlated (r=0.64), however, pH and PCO2 were only loosely correlated (r=0.17). Glucose levels were correlated with indicators of dehydration and kidney function (blood urea nitrogen (BUN), r=0.44; creatinine, r=0.42; glucose-corrected sodium, r=0.32). Among children with repeat DKA episodes, PCO2 levels tended to be similar at the first vs. second episode (r=0.34), although pH levels were only loosely correlated (r=0.19). CONCLUSIONS: Elevated glucose levels at DKA presentation largely reflect alterations in glomerular filtration rate. pH and PCO2 are weakly correlated suggesting that respiratory responses to acidosis vary among individuals and may be influenced by pulmonary and central nervous system effects of DKA.