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

Objective: To 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 Design: We 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 non-gastrointestinal symptoms).

Results: Mean CIT for controls was 31 +/- 2 micromol/L. In patients with SBS (n = 24), serum CIT correlated linearly with percent enteral calories (R = 0.85; P <.001) and with bowel length (R = 0.47; P < or =.03). CIT level in patients with SBS weaned off PN was 30 +/- 2 micromol/L; in those subsequently weaned off PN, 20 +/- 2 micromol/L; and in those who would remain PN-dependent, 11 +/- 2 micromol/L ( P < or =.01). Serum CIT > or =19 micromol/L had 94% sensitivity and 67% specificity for being off or coming off total PN.

Conclusions: Serum CIT level >19 micromol/L in children with SBS is associated with development of enteral tolerance and may be a useful predictive test.