Amino Acid Concentrations in Critically Ill Children Following Cardiac Surgery*

Abstract

Guidelines for administering amino acids to critically ill children are largely based on uncontrolled observational studies and expert opinion, without support from rigorous outcome studies. Also, data on circulating amino acid concentrations during critical illness are scarce. We thoroughly studied the time profiles of circulating amino acid concentrations in critically ill children who received standard nutritional care according to international guidelines. This is a subanalysis of pediatric critically ill patients included in a large (n = 700) randomized controlled study on intensive insulin therapy. The study was conducted at a university hospital PICU. We studied 100 patients in PICU for at least 3 days following cardiac surgery. Patients were assigned to intensive insulin therapy targeting normal-for-age fasting blood glucose concentrations or insulin infusion only to prevent excessive hyperglycemia. Plasma amino acid concentrations were measured at admission, day 3, and day 7 in PICU. At admission, the concentrations of most amino acids were comparable to those reported for healthy children. Total amino acid concentrations remained stable during ICU stay, but individual amino acids showed different time profiles with eight of them showing an increase and five a decrease. Nonsurviving children had higher total amino acid concentrations and individual amino acids compared with survivors at admission and/or during ICU stay. Intensive insulin therapy lowered the concentrations of total amino acids and several individual amino acids. Neonates showed somewhat different amino acid profiles with rather increased concentrations from baseline with time in ICU for total amino acids and several individual amino acids as compared with older infants and children. Circulating amino acid concentrations in critically ill children after cardiac surgery differ according to survival status, blood glucose control with intensive insulin therapy, and age.