Randomization and masking
Patients were randomized in a 1:1 ratio to either L-citrulline (intervention group) or placebo (control group). The randomization sequence was generated using SAS 9.4 software (SAS Institute, Cary, NC, USA) and used blocks of size 6, stratified by site.To maintain blinding, treatments were prepared by a nurse from another unit who was not involved in the clinical trial.