A comparison of essential and general amino acid infusions in protein-depleted patients receiving parenteral alimentation.

Six malnourished patients were studied during intravenous nutrition therapy to compare the efficiency of essential and general amino acids when given as the sole nitrogen source during intravenous nitrogen therapy. A cross-over design was used so that each patient received both essential amino acids plus arginine and histidine and a general amino acid solution in random order. Glucose provided the remainder of the energy and both infusions contained 2 g of amino acid per 100 kcal. Each patient's daily urea nitrogen production was greater during infusion of the general amino acid solution. Consequently, nitrogen intake minus urea nitrogen production was significantly greater when the essential amino acid solution was infused. Plasma amino acid levels were determined on each patient during both essential and general amino acid infusion. Abnormalities tend to reflect the composition of the amino acid solutions as well as their administration directly into the systemic circulation bypassing the portal circulation.