Combined intravenous bolus amino acid supplementation and mobilization on early muscle loss in critically ill adults: a randomized controlled trial

Abstract

Background: Muscle wasting is a hallmark of critical illness. We evaluated the effect of amino acid supplementation and mobilization on early muscle loss in critically ill patients. Methods: We conducted a randomized parallel-group trial involving adult patients admitted to the surgical intensive care unit of a tertiary hospital. Participants were randomly assigned to two groups, both receiving standard care nutrition and mobilization. The intervention group also received a daily intravenous amino acid bolus with 45 min of cycle ergometry, starting on days 3–4 for a mean of 6 days. The primary co-outcomes were changes in vastus lateralis myofiber cross-sectional area (from biopsies) and ultrasound-derived rectus femoris cross-sectional area, measured between the preintervention (day 2) and postintervention (day 8) time points. Analyses were conducted using mixed-model analysis of variance and least significant difference testing. Secondary outcomes included the protein-to-DNA ratio, muscle echogenicity, whole-body phase angle, muscle strength (Medical Research Council sum score) and physical capability (6-min walk test). Results: Fifty patients (90% male, age 37 ± 12 years) were included. Standard of care participants received 1.23 ± 0.18 g/kg/day protein; intervention participants 1.57 ± 0.27 g/kg/day, including 0.37 ± 0.05 g/kg/day from the supplement. Muscle loss occurred significantly over time (biopsy P = 0.01; ultrasound P < 0.001), with no significant differences between groups. Similarly, no significant differences were observed in protein-to-DNA ratio, muscle echogenicity, phase angle, muscle strength, or physical capability. Conclusion: A short-duration combined intervention of intravenous bolus amino acids and cycle ergometry, limited to the acute phase of critical illness, did not reduce muscle loss or improve muscle quality, strength, or physical capability.