Study interventions
The study drug was 5 g of enterally administered L-citrulline (Proteocit, Citrage, Boissy St Léger-France) every 12 h for 5 days, starting within 24 h of inclusion. L-Citrulline was administered enterally through nasogastric tube feeding in 30 s. Patients randomized to placebo received a standard isonitrogenous, isocaloric preparation of nonessential amino acids, including alanine, glycine, aspartic acid, and proline, in a matching volume (50 mL) using the same techniques at the same time points. All patients included in the study received enteral nutrition to achieve recommended caloric and protein intakes [