Orthotopic liver transplantation is the definitive treatment for end-stage liver failure, with renal failure being an important complication of this procedure that has implications for long- and short-term prognosis, affecting ICU stay and hospitalization time. Several studies have suggested that intravenous amino acids, particularly L-arginine, may have protective effects on renal function due to increased renal blood flow, which could be explained by enhanced production of nitric oxide among other mechanisms that are still unclear. In this context, we developed the hypothesis that the infusion of an amino acid solution in the perioperative period could reduce the incidence of acute renal failure in this group of patients; for this, we conducted a monocentric, analytical, prospective, interventional pilot study comparing standard treatment (in historically transplanted patients) with a group of patients who were administered amino acids in the perioperative period, considering that this medication is low-cost and has practically minimal side effects.

The primary objectives will be to measure the occurrence of acute kidney injury according to KDIGO criteria, evaluate the behavior of BUN and creatinine, as well as the initiation and duration of renal replacement therapy if necessary, use of vasopressors, diuresis, liver enzymes and bilirubin, lactate; this will be during the first 10 days postoperatively. Additionally, as a secondary objective, to measure all-cause mortality at 30 days. The study protocol must be approved by the institution's ethics committee. The treatment with amino acids will be carried out using Aminoven 10% from Fresenius Kabi available at the hospital. Fresenius Kabi has not had and will not have any role in the conception, development, data collection, and/or tabulation of data and/or publication of the results of this study. Data collection will be undertaken by specific personnel chosen from among those healthcare providers of liver transplantation, surgery, anesthesiology, and intensive care services.

Inclusion Criteria:

• All patients assigned to receive a liver transplant will be evaluated for eligibility.
• Patients over 18 years old scheduled for a liver transplant will be considered eligible if it is expected that they will have an ICU stay of at least 24 hours in the immediate postoperative period, regardless of the cause of liver failure and whether it was stable liver failure or acute on chronic liver failure.
• They must have a baseline measurement of serum creatinine that does not exceed 30 days prior to surgery or can be taken before the transplant surgery.

Exclusion Criteria:

• Patients under 18 years old will be excluded.
• Patients with a need for chronic hemodialysis, patients with chronic kidney disease with an estimated glomerular filtration rate of less than 30 ml per minute per 1.73 square meters of body surface area calculated by the Cockcroft-Gault equation.
• Patients with acute renal failure requiring acute intermittent or continuous renal replacement therapy during the hospitalization for surgery.
• Patients who refuse informed consent to participate in the study.

REQUIRES NEW REVIEW BY THE ETHICS COMMITTEE