Adaptation to amino acid infusion in patients undergoing operation

Urine ketone levels were measured in patients receiving peripheral amino acid solutions, and the results were correlated with changes in nitrogen balance. Thirty well-nourished patients who were to undergo cystectomy were placed on liquid, noncarbohydrate diets 3 days before operation, and no oral intake was allowed until 7 days after operation. Crystalline amino acid (1.3 to 1.5 gm/kg/day) solutions were infused continuously from 3 days before to 7 days after operation. Blood was obtained 3 days before and 3, 7, and 10 days after operation; 24-hour urine outputs were determined daily. Qualitative urine acetone levels were determined four times daily. During the infusion period, 14 (47%) patients developed ketonuria (group I); 16 patients did not (group II). The mean serum glucose levels ranged from 99 to 107 mg/dl in group I and from 108 to 113 mg/dl in group II (P less than 0.05). The mean serum transferrin level decreased after operation to 117 mg/dl in group I and 97 mg/dl in group II. The mean cumulative adjusted nitrogen balance was -24 +/- 8 gm in group I and -47 +/- 9 gm in group II (P less than 0.05). No patient developed sepsis. Qualitative testing of urinary ketones correlated with significant alterations in blood urea nitrogen, serum glucose, transferrin, and cumulative adjusted nitrogen balance. The bedside determination of urinary ketones may be useful in assessing a patient's adaptation to peripheral amino acid infusions.