Comparison of Administration of Two Standard Intravenous Amino Acid Formulas to Severely Brain-Injured Patients

Abstract

Twenty severely brain-injured patients with Glasgow Coma Scale scores of 4-9 were prospectively randomized to receive one of two standard amino acid formulas, starting with the first day of hospital admission up to day 14 postinjury. Formula 2 (patient group 2) had 54 percent more leucine, 53 percent more isoleucine, 74 percent more valine, 28 percent less phenylalanine, 31 percent less methionine, 111 percent more proline, 38 percent less alanine, and 38 percent less glycine than formula 1 (patient group 1). Groups 1 and 2 received statistically equal overall mean parenteral nutrition calories and protein (2173 +/- 147 vs. 2059 +/- 143 kcal, and 77 +/- 12 vs. 83.1 +/- 6 g, respectively). There was a significant difference in overall mean urinary urea nitrogen excretion (group 1 = 24.6 +/- 1.3 vs. group 2 = 18.3 +/- 1.1, p = 0.02) and nitrogen balance (group 1 = -8.0 +/- 2.1 vs. group 2 = +1.8 +/- 1.2, p = 0.01). Mean overall isoleucine values were significantly higher in group 2 (overall mean 77 mumol/L vs. 62 mumol/L, p = 0.04). Phenylalanine levels were significantly higher in group 1 (107 mumol/L) versus group 2 (82 mumol/L) patients (p = 0.01). Arginine levels were significantly higher in group 1 (78 mumol/L) versus group 2 (49 mumol/L) patients (p = 0.0002). This observation suggests that some standard intravenous amino acid formulas may be more apt to promote positive nitrogen balance than others.

Traumatic Brain Injury Alters Methionine Metabolism: Implications for Pathophysiology

“…Only a few clinical studies have examined the consequences of amino acid supplementation after TBI. Ott et al ( 1988 ) compared the effects of two different intravenous amino acid formulations on amino acid levels and nitrogen balance in sTBI patients. Their results indicated that positive nitrogen balance could be achieved with early administration of some combinations of amino acids, although neither the specific amino acids responsible for this improvement, nor their effect on outcome was assessed (Ott et al, 1988 ).…”

“…Ott et al ( 1988 ) compared the effects of two different intravenous amino acid formulations on amino acid levels and nitrogen balance in sTBI patients. Their results indicated that positive nitrogen balance could be achieved with early administration of some combinations of amino acids, although neither the specific amino acids responsible for this improvement, nor their effect on outcome was assessed (Ott et al, 1988 ). BCAAs play important roles in regulating protein synthesis, gluconeogenesis, and energy metabolism as well as functioning as a major source of nitrogen for producing glutamine and nitric oxide (Fernstrom, 2005 ; Jeter et al, 2013 ).…”

Metabolomic Analysis in Neurocritical Care Patients

“…Taken together, methionine supplementation in TBI patients during the acute injury phase could potentially improve disease prognosis. Currently, only a few clinical studies are available assessing the potential benefits of intravenous methionine supplementation [ 48 , 49 , 50 ]. However, Dash et al, 2016 did not account for variability in plasma methionine concentrations due to food source, a potential limitation of the study.…”

Management of Elevated Intracranial Pressure

“…214,215 Enriched parenteral and enteral feedings containing branched chain amino acids (BCAA) have been shown to improve nitrogen balance with decreased nitrogen excretion. 217,218 Effect on morbidity and mortality was not assessed in these studies. Relatively few studies have specifically addressed the impact of providing a high-protein (including BCAA) high-caloric intake on overall outcome in head-injured patients.…”