Peripheral plasma amino acid abnormalities in rehabilitation patients withsevere brain injury

Objective: Acute severe brain injury causes an increased mobilization of am ino acids from tissue. The plasma amino acid profile of patients undergoing rehabilitation after brain injury is unknown. This study was aimed at deli neating the plasma amino acid profile of rehabilitation patients with brain injury. Design: Peripheral plasma aminogram, lactate, pyruvate, glycerol, ketone bo dy, and carnitine concentrations were determined in 11 patients with brain injury (34.6 +/- 15 years old, 60 +/- 16.8 days after injury) and in 8 cont rols. Resting energy expenditure and nitrogen balance were also determined. Results: (1) All essential amino acids and about 50% of nonessential amino acids were significantly lower in brain injury patients than in controls (p < .05). (2) Plasma amino acids were lower irrespective of either energy an d protein intake or nitrogen balance. (3) Total carnitine concentration and esterified/free carnitine ratio were higher in brain injury patients than in controls (p < .05). Conclusions: Rehabilitation patients with brain injury may have an importan t reduction of their plasma aminogram. Muscle tissue depletion and the pers istence of a hypercatabolic state caused by subclinical infections, pressur e sores, and immobility may contribute to this reduction.