Objective: To assess the pressor response to phenylephrine infusion before and after hydrocortisone in severe trauma patients and to correlate this response with their adrenal reserve.
Design: Prospective clinical study.
Setting: Surgical intensive care unit in a university teaching hospital.
Patients: Twenty-three young trauma patients (Injury Severity Score, 38 +/- 14) were studied at the end of the resuscitative period (27 +/- 15 hrs after trauma).
Interventions: Total cortisol response to intravenous corticotropin bolus (250 microg) was obtained. Total cortisol response <9 microg/dL defined an impaired adrenal function and the patient was called a nonresponder. Twelve to 24 hrs following this stimulation, phenylephrine was infused in a stepwise manner to establish the phenylephrine-mean arterial pressure dose-response curve before and after intravenous hydrocortisone administration (50 mg). An Emax model was used to describe the curve; the influence of the group (responder/nonresponder), the sequence (before/after hydrocortisone), and three covariates (Injury Severity Score, shock, and interleukin-6) were thereafter tested.
Measurements and main results: Forty-three percent of patients were nonresponders. Total cortisol response was not correlated with serum albumin concentration and was negatively correlated with the interleukin-6 concentration. A trend for a higher incidence of nonresponders (53% vs. 36%) and a lesser total cortisol response (7.9 +/- 5.1 vs. 12.5 +/- 5.1 microg/dL) was observed in the shock patients. A phenylephrine dose-response structure (E0, ED50, and Emax) was described without influence of the group and the sequence. However, hydrocortisone induced a 37% decrease in ED50 without change in Emax in the shock patients.
Conclusion: An acute administration of hydrocortisone increases the sensitivity to alpha1-adrenoceptor stimulation in fully resuscitated severe trauma patients following hemorrhagic shock. This effect is independent of the adrenal reserve of the patients and different from that previously reported in septic patients.