Evaluation of amino acid kinetics during low-dose continuous renal replacement therapy in patients with acute kidney injury: a prospective single-center study.

Abstract

Objective: Amino acid and protein loss during continuous renal replacement therapy (CRRT) has been proposed to contribute to protein energy wasting (PEW) in patients with acute kidney injury (AKI); however, the actual amount removed remains unclear. We investigated the loss of amino acids and proteins in the filtrate during CRRT in patients who did not receive nutritional supplementation.

Methods: A total of 19 patients with AKI who received low-dose continuous venovenous hemofiltration (CVVH) were included. Blood samples were collected before CVVH initiation and at 30, 60, 120, 240 minutes thereafter, and a filtrate sample was collected at 240 minutes. Changes in blood amino acid concentrations during 240-minute CVVH session were measured. The amino acid and protein concentrations in the filtrate were determined at the end of 240-minute CVVH session, and the amounts of amino acids and proteins lost during 240-minute CVVH were calculated.

Results: Median total amino acid (TAA) blood concentrations did not decrease and were near the lower limits of the reference ranges. Median concentrations of 3-methyl histidine, a marker of skeletal muscle catabolism, were above the upper limits of the reference ranges throughout the CVVH session. The median TAA loss during the 240-minute CVVH session was 0.95 g. In 10 patients with detectable proteins in the filtrate, the median protein loss was 2.52 g.

Conclusion: These results suggest that optimal nutritional management in patients with AKI who receive CVVH should take into account amino acid and protein loss and hypercatabolism.