Cytrulline as a marker of complete or partial weaning off parenteral nutrition in adult patients – observatory pilot study

Abstract

Aim of the study: Citrulline is a recognized marker of small bowel mass and function. The aim of this study was to identify plasma citrulline concentration that permitted adult patients to be partially or completely weaned off total parenteral nutrtion (TPN).<br>Materials and Methods: We measured plasma citrulline in 29 adult TPN patients in Warsaw hospital in 2014 and 2015. We evaluated how many of those patients were weaned from TPN or whether there was a decrease in the frequency of parenteral nutrition (PN) over the following year. Citrulline was assayed in deproteinised plasma samples using HPLC with fluorescence detection after derivatization in a timed reaction with o-phtalaldehyde and mercaptoethanol as described by Kilpatric. The group of weaned patients were compared to the TPN-dependent using Student’s t-test.<br>Results: Citrulline levels among the 29 patients ranged from 6.1 to 44.9 μmol/L (average 19.9 μmol/L). Six patients were completely weaned off PN over one year. Their citrulline levels were between 19,5 and 44.9 (average 28,7) μmol/L and were the highest measured in the patient population. Four patients with citrulline levels between 19.0 and 30.6 (average 23.8) μmol/L) had PN 5 days each week. The 19 patients who were totally dependent on PN had citrulline levels between 6.1 and 18.8 (average 15.3) μmol/L. There was a statistically significant difference between weaned and dependent on parenteral nutrition patients (p=0.0001).<br>Conclusions: Patients receiving TPN who have a high blood citrulline level may be able to be weaned off PN. This may reflect better intestinal mass and function. Citrulline levels may be a good predictor for weaning patients off PN or diminishing the frequency of PN.