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

Abstract

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.