Nicardipine for controlled hypotension during spinal surgery.

Nicardipine is the first intravenously administered dihydropyridine calcium channel blocker. Its primary physiologic actions include vasodilatation with limited effects on the inotropic and dromotropic function of the myocardium. Several reports have documented its use in adult patients for pharmacologic control of blood pressure. We present our experience with nicardipine as an agent for controlled hypotension during spinal surgery in 24 children. After the induction of general anesthesia, nicardipine was started at 5 (22 patients) or 10 micrograms/kg/min (two patients). The target mean arterial pressure (MAP) of 55-65 mm Hg was reached in 5.1 +/- 2.1 min (range, 2-10). Intraoperative infusion requirements to maintain the target MAP varied from 0.5 to 7 micrograms/kg/min (mean, 2.5 +/- 1.1). No adverse effects related to nicardipine were noted. Nicardipine appears to be an effective agent for controlled hypotension in children. Future studies are required to determine its advantages/disadvantages compared with more commonly used agents such as sodium nitroprusside or adrenergic antagonists.