Comparison of L-arginine and L-citrulline oral supplementation in head trauma ICU patients receiving enteral nutrition: A randomized double blind clinical trial

Specific amino acids seem to have crucial role in the management of critically ill patients. This study aimed to compare the effect of L-arginine and L-citrulline supplementation on overall prognosis of critically ill patients.

A total of 105 head trauma ICU patients were recruited in this double-blind randomized clinical trial. Patients in the treatment groups took 10 gr per day oral L-Arginine or L-citrulline for 10 days. Demographic characteristics and anthropometric measurements were recorded. Nitric oxide (NOx), pre-albumin, pro-oxidant, anti-oxidant balance, fasting blood sugar, lipid profile, liver enzymes, serum electrolytes, blood urea nitrogen, creatinine and serum amino acids were measured. Gastrointestinal complications, ventilator need, length of hospital stay and 28-day mortality were recorded. The K2 testing system was used to compare the qualitative variables. Repeated measures ANOVA were used to compare means across variables. In case of significant time-group interaction, between group comparisons of changes at day 11 were done using ANOVA followed by Tukey or Mann Whitney analysis. When time effect factor was significant, the within-group comparison of values was performed by paired samples t test or Wilcoxon.

We observed no significant changes in NOx and PAB (P= 0.8, P= 0.1 respectively). There was a significant increase in serum LDL (P= 0.02) which was higher in the control group after 10 days of supplementation. There was non-significant increase in serum L-arginine in all three groups (P=0.36). However, changes of serum L-arginine was significant in the citrulline group (P=0.048). Serum L-citrulline was higher in the citrulline group compare to the arginine group (P=0.04).

L-arginine and L-citrulline supplementation did not increased NOx levels more than the control group. Also, PAB balance was not different among the intervention groups and the control group. L-arginine and L-citrulline had no significant effects on length of hospital stay, mortality rate, ventilator need and other factors evaluated in this study.