Evaluation of Amino Acid Kinetics During Low-Dose Continuous Renal Replacement Therapy in Patients With Acute Kidney...

Amino acid and protein loss during continuous renal replacement therapy has been proposed to contribute to protein-energy wasting 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 continuous renal replacement therapy in patients who did not receive nutritional supplementation.

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, and 240 minutes thereafter, and a filtrate sample was collected at 240 minutes. Changes in blood amino acid concentrations during 240-minute CVVH sessions were measured. The amino acid and protein concentrations in the filtrate were determined at the end of the 240-minute CVVH session, and the amounts of amino acids and proteins lost during 240-minute CVVH were calculated.

The median total amino acid blood concentrations did not decrease and were near the lower limits of the reference ranges. The 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 total amino acidloss 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.

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.