Branched chain metabolic support. A prospective, randomized, double-blind trial in surgical stress.

A prospective, randomized, double-blind trial of the nutritional effects of branched chain modified amino acid solutions was undertaken in 23 surgical patients within 24 hours of the onset of major general surgery, polytrauma, or sepsis. The effects were evaluated in the absence of abnormalities of oxygen transport and perfusion in an isocaloric/isonitrogenous setting where the major difference between the groups was the amount of branched chain amino acids received. Both groups received balanced parenteral nutrition with 1.5 gm/kg/day of amino acids, 30 calories/kg/day of glucose, and 7 calories/kg/day of fat. At the end of the 7-day study interval, the group receiving the branched chain enriched therapy at 0.7 gm/kg/day of branched chain amino acids had improved nitrogen retention; an elevation of their absolute lymphocyte count from 800 to 1800/mm3, a reversal of anergy to recall skin test antigens in 60% of the patients, and improved plasma transferrin levels (p less than 0.03). Nutritional support using the modified amino acid metabolic support solutions has beneficial effects during the stress interval that do not seem as achievable with current commercially available nutritional support regimens.

Does modified amino acid total parenteral nutrition alter immune-response in high level surgical stress.

A randomized prospective double-blinded study was conducted in patients in moderate to high level surgical stress to ascertain the effect of high dose branched-chain (BcAA) hyperalimentation on skin test reactivity and lymphocyte count. Isocaloric, isonitrogenous balanced total parenteral nutrition solutions were administered to two treatment groups. The study group received the high dose (45% BcAA) solution while the control group received a standard amino acid solution (24.2% BcAA). All patients received 1 to 1.5 g/kg/day of amino acids and 30 nonprotein cal/kg/day, with 30% of them as fat. Immune function was assessed by absolute lymphocyte count and delayed cutaneous hypersensitivity on days 0 and 7 of therapy. Absolute lymphocyte count showed a marked improvement in patients receiving high dose aBcAA (p less than 0.03). All patients were anergic at baseline; a much greater percentage of skin test reactivity was observed in the BcAA group on day 7 (p less than 0.03). They were also in positive nitrogen balance. The data suggest that improved nitrogen retention and immune-competence is possible with branched-chain-enriched hyperalimentation in high level surgical stress.

Nitrogen retention in critically ill patients is proportional to the branched chain amino acid load.

The nitrogen retention effect of branched chain enriched parenteral nutrition (BcAA) during surgical stress and polytrauma was evaluated in a prospective, randomized, double blind study in 32 patients. The doses of BcAA were 0.16, 0.3, 0.5, and 0.7 g/kg . day with a total amino acid load of 1 or 1.5 g/kg . day. It was provided in a setting of 30 glucose cal/kg . day with 7 cal/kg . day of iv fat also given to 16 patients. After the 7-day study was completed, analysis of the 4 treatment groups of 8 patients each demonstrated that there was an increased nitrogen retention effect of BcAA, that the effect was proportionate to BcAA load, that the effect started at 0.5 g of BcAA/kg . day in a setting of balanced nutritional support, and that the effect was consistent with a BcAA influence on protein synthesis. There were no complications or side-effects from high dose BcAA. Metabolic support of the stress response in ICU patients has become a clinical reality.