Objective: To determine the effect of a low-calorie parenteral nutrition (PN) regimen on the incidence and severity of hyperglycemia and insulin requirements.
Design: Prospective, randomized, clinical trial.
Setting: Urban, university-affiliated, level-I trauma center.
Patients: Consecutive surgical patients requiring PN.
Interventions: Patients were randomized to receive either a low-calorie PN formulation (20 nonprotein kilocalories per kg per day) or a standard PN formulation (30 nonprotein kilocalories per kg per day). Lipid-derived calories were standardized to 1000 kilocalories three times weekly for all patients; consequently, the number of calories varied only by the amount of carbohydrate administered. Protein requirements were individualized on the basis of estimated metabolic stress. Hyperglycemia was defined as a blood glucose level > or = 200 mg/dL.
Measurements and main results: Forty patients were evaluated (low-calorie PN, n = 20; standard PN, n = 20). Demographics of the two groups were similar. The incidence of hyperglycemic events was significantly lower in the low-calorie group (0% [0-0.5] vs. 33.1% [0-58.4]; p = .001]. Additionally, the severity of hyperglycemia was also lower in the low-calorie group (mean glucose area under the curve = 118 +/- 22 [mg x hr]/dL vs. 172 +/- 44 [mg x hr]/dL; p < .001). This resulted in lower average daily insulin requirements (0 [0-0] units vs. 10.9 [0-25.6] units; p < .001.). The only predictor of hyperglycemia was a dextrose administration rate >4 mg/kg/min.
Conclusions: : Administration of a low-calorie PN formulation resulted in fewer and less-severe hyperglycemic events and lower insulin requirements. PN regimens should not exceed a dextrose administration rate of 4 mg/kg/min to avoid hyperglycemic events.