Serum citrulline levels correlate with enteral tolerance and bowel length in infants with short bowel syndrome

ObjectiveTo determine if serum levels of CIT (a nonprotein amino acid synthesized by the intestine) correlate with total parenteral nutrition (PN)-independence in children with short bowel syndrome (SBS).Study designWe prospectively obtained serum amino acid profiles over a 24-month interval from all infants with SBS 3 weeks to 4 years of age. Remaining small intestine length was recorded at surgery, and percent enteral calories tolerated (enteral calories divided by enteral plus parenteral calories x 100) was determined in 24 infants with SBS and 21 age-matched controls (blood drawn for nongastrointestinal symptoms).ResultsMean CIT for controls was 31 +/- 2 @mmol/L. In patients with SBS (n=24), serum CIT correlated linearly with percent enteral calories (R=0.85; P =0.47; P @?.03). CIT level in patients with SBS weaned off PN was 30 +/- 2 @mmol/L; in those subsequently weaned off PN, 20 +/- 2 @mmol/L; and in those who would remain PN-dependent, 11 +/- 2 @mmol/L (P @?.01). Serum CIT >=19 @mmol/L had 94% sensitivity and 67% specificity for being off or coming off total PN.ConclusionsSerum CIT level >19 @mmol/L in children with SBS is associated with development of enteral tolerance and may be a useful predictive test.