The Effect of L-Citrulline Supplementation on Outcomes of Critically Ill Patients under Mechanical Ventilation; a Double-Blind Randomized Controlled Trial

Introduction: Effective parenteral and enteral amino acid replacement is crucial for critically ill patients with altered amino acid metabolism. This study aimed to assess the effects of l-citrulline supplementation on the clinical and laboratory outcomes in critically patients. Methods: This was a double-blind placebo-controlled randomized clinical trial. 82 critically ill patients who were expected to receive mechanical ventilation for more than 72 hours were selected. The patients were assigned to either a placebo or an intervention group. The patients in the placebo group received 10 gr of microcrystalline cellulose and the ones in the intervention group were given l-citrulline daily for 7 days. Serum levels of fasting blood sugar (FBS), lipid profile, hepatic enzymes, serum electrolytes, urea nitrogen, creatinine, and C-reactive protein (CRP) were evaluated before and after the intervention. Duration of invasive ventilation, intensive care unit (ICU) length of stay, ventilator-free days, and 28-day mortality rate were recorded and compared between groups. Results: Eighty-two patients completed the trial. No statistically significant differences were observed between the two groups in terms of age (p = 0.46), sex (p = 0.49), body mass index (BMI) (p = 0.41), Sequential Organ Failure Assessment (SOFA) Score (p = 0.08), Clinical Pulmonary Infection Score (CPIS) score (p = 0.76), Acute Physiology and Chronic Health Evaluation (APACHE II) score (p = 0.58), risk factors (p = 0.13), ICU stay before randomization (p = 0.32), and reason of admission (p = 0.50) before the intervention. Citrulline group had a notable reduction in FBS (p = 0.04), total cholesterol (TC) (p = 0.02), low density lipoprotein (LDL-C) (p