Effect of Recombinant Human Insulin-like Growth Factor I and Early Total Parenteral Nutrition on Immune Depression Following Severe Head Injury

OBJECTIVE: To determine the effects of insulin-like growth factor I (IGF-I) and aggressive nutrition on CD4/CD8 ratios following head injury. DESIGN: Randomized controlled trial. SETTING: An urban level 1 trauma center. PARTICIPANTS: Head-injured patients with a Glasgow Coma Scale score of 4 to 10 within 6 hours of hospital admission requiring no major extracranial surgery with the exception of isolated lower-extremity fracture fixation. Fourteen patients were recruited and 11 completed the study. INTERVENTIONS: Patients were randomized to a continuous infusion of saline or 0.01 mg/kg per hour of recombinant human (rh) IGF-I. Both groups received parenteral nutrition and rapidly advanced to a total protein intake of 2 g/kg per day and a maximum nonprotein calorie intake of 40 kcal/kg per day. The nonprotein prescription was 1.25 times the metabolic energy expenditure determined by metabolic cart not to exceed a nonprotein calorie intake of 40/kcal. MAIN OUTCOME MEASURES: The CD4/CD8 ratios and serum IGF-I levels on days 1, 7, and 14. RESULTS: Administration of early aggressive nutrition eliminated the depressed CD4/CD8 ratio usually seen after head injury; administration of IGF-I increased the CD4/CD8 ratio while IGF-I levels were elevated. CONCLUSIONS: Infusion of rhIGF-I and aggressive early intravenous nutrition affects the immunologic response of patients with severe head injury.