Amino Acid Deficiency Secondary to Continuous Venovenous Hemofiltration in Acute Decompensation of Organic Acidemias: An Anabolic Dead End?

Abstract

Objective: To evaluate the impact of continuous renal replacement therapy (CRRT) on plasma amino acid (AA) concentrations in patients with acute metabolic decompensation of organic acidemias (OAs), and to explore whether AA supplementation during CRRT may mitigate AA depletion.

Design: Multicenter retrospective observational study.

Setting: PICUs managing acute metabolic decompensations of OAs.

Patients or subjects: Patients with confirmed OAs who underwent CRRT for severe acute metabolic decompensation.

Interventions: CRRT was initiated according to current guidelines in cases of severe decompensation. Standard metabolic management included high caloric intake through carbohydrates and lipids with temporary protein withdrawal (24-48 hr). In one patient, AA supplementation (2 g/kg) during CRRT combined with thiamin and citrate (anaplerotic therapy) was administered.

Measurements and main results: Plasma AA concentrations were measured before and after CRRT in nine patients with a median age of 21 days (interquartile range [IQR], 3-570 d). Quantitative variables are expressed as medians (IQR, 25th-75th). Before CRRT, 31% (95% CI, 24-39) of plasma AAs were below the normal range compared with 69% (95% CI, 59-77) after CRRT (p < 0.0001). A significant increase in lactatemia was observed following CRRT, without evidence of organ failure: median 2.2 mmol/L (IQR, 1.3-2.3) before CRRT vs. 5.3 mmol/L (IQR, 3.2-7.1) after CRRT; Hodges-Lehmann median difference +3.2 (95% CI, 0.8-5.6; p = 0.0065). In the patient receiving AA supplementation with anaplerotic therapy, plasma AA status improved markedly, with 65% of AAs below normal before CRRT vs. 15% after CRRT.

Conclusions: In acute decompensated OAs, CRRT performed without protein supplementation, as currently recommended, significantly reduces total plasma AA concentrations and may impair restoration of anabolism. AA infusion during CRRT could help preserve or restore protein anabolism. Prospective studies are needed to assess the safety and efficacy of AA supplementation during CRRT, with or without anaplerotic therapy, in this setting.