A phase II study to evaluate the efficacy of dexmedetomidine for sedation in the medical intensive care unit

Abstract

Objective: To evaluate dexmedetomidine for sedation of patients in the medical ICU. Design and setting: Prospective observational study in an intensive care unit of a university hospital. Patients: Twelve ventilated patients with median APACHE II score 23 (range 10-26). Interventions: Patients received a loading dexmedetomidine infusion of 1 μg kg-1 over 10 min followed by a maintenance infusion rate of 0.2-0.7 μg kg-1 h-1 for up to 7 days. After experience with the first four patients this maintenance rate of infusion was increased to a maximum of 2.5 μg kg-1 h-1. If required, propofol and morphine provided rescue sedation and analgesia, respectively. Results: The first four patients with dexmedetomidine infusion at 0.7 μg kg-1 h-1all required rescue sedation with a propofol infusion. A protocol amendment allowed the next eight patients to receive higher dexmedetomidine infusions (mean 1.0 ± μg kg-1 h-1). Five of the next eight patients did not required propofol, and two patients only required minimal propofol infusions (20-40 mg h-1). A further patient, with hepatic encephalopathy, required a propofol at 50-100 mg h-1. Only modest falls in arterial pressure, heart rate and cardiac output were seen, and no rebound sequelae occurred on discontinuation of dexmedetomidine. Adverse cardiovascular events were nearly all confined to the initial loading dose period of dexmedetomidine. Conclusions: Sedation with dexmedetomidine is efficacious in critically ill medical patients requiring mechanical ventilation in the intensive care unit. A reduction in loading infusion is advised, but higher maintenance infusions may be required to that seen previously in the postoperative ICU patient.