Low-Dose Postoperative Amino Acid Infusion and Kidney Protection After Cardiac Surgery: A Before-and-After Observational Cohort Study

Objectives: To evaluate the real-world impact of implementing routine postoperative amino acid infusion on cardiac surgery–associated acute kidney injury (AKI). Design: Before-and-after study. Setting: Intensive care unit (ICU). Participants: Adult patients undergoing cardiac surgery. Interventions: Ringer lactate solution as maintenance solution after admission to the ICU for the first 48 postoperative hours versus 4% amino acid solution infusion for the first postoperative 48 hours. Measurements and Main Results: The primary outcome was AKI development according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria (stages 1, 2, and 3). The authors performed a multivariable analysis to identify predictors of AKI in the study cohort. During the study period, 520 patients underwent cardiac surgery and were included in the final study cohort: 147 consecutive patients received Ringer lactate solution (June 15, 2024, or earlier) while 373 consecutive patients received amino acid solution (after June 15, 2024). The overall incidence of AKI was higher in the Ringer lactate group than in the amino acid group (41.5% v 30.0%, p = 0.012), with the magnitude and direction of findings confirmed for stage 1, 2, and 3 AKI. The authors performed a multivariable analysis to identify predictors of AKI. After adjustment for potential confounders, amino acids remained associated with a reduction in the overall incidence of AKI in a multivariate analysis. Conclusions: Postoperative amino acids are effective in reducing AKI in a real-world setting.