Effects of human growth hormone on fuel utilization and mineral balance in critically ill patients on full intravenous nutritional support.

PURPOSE

The effects of recombinant human growth hormone (GH) on fuel utilization, mineral and fluid balance in critically ill patients were studied.

METHODS

Twenty patients requiring mechanical ventilation and receiving standard parenteral nutrition were studied. GH 0.1 mg/kg/day (n = 10) or placebo (n = 10) was administered as continuous intravenous infusion for 3 days. Plasma mineral levels, urinary nitrogen, and mineral excretion were measured. Indirect calorimetry was used to calculate energy production rate and fuel utilization.

RESULTS

Insulin-like growth factor I concentrations increased: day 4 GH, 18.9 +/- 7.0 ng/mL; controls 11.6 +/- 3.2 ng/mL (P < .05). During GH administration, the nitrogen balance became zero, whereas it remained negative in controls (P = .03). Fuel utilization did not differ between the groups. Neither did oxygen consumption, carbon dioxide production, or the respiratory quotient (RQ). Nonprotein RQ showed a tendency to decrease in the GH group, whereas an increase was present in controls. Mineral balance improved in both groups. Phosphate balance improved by 250% in the GH group (P = .054).

CONCLUSIONS

GH administration in critically ill patients reduces nitrogen loss and improves phosphate retention but does not have an important effect on fuel utilization.