Optimal dose of nicardipine for maintenance of hemodynamic stability after tracheal intubation and skin incision.

Abstract

To determine the optimal dose of nicardipine (N) for maintenance of hemodynamic stability during the postinduction period, we designed a randomized, double-blind, placebo-controlled, dose-ranging study using four different doses of N administered after a standardized anesthetic induction sequence. A total of 106 patients were assigned to one of the following treatment groups: saline (control), N 0.5 mg (N0.5), N 1 mg (N1), N 2 mg (N2), and N 4 mg (N4). The study medication was administered intravenously (I.V.) in 2.5 mL of saline over 30 s 2 min before laryngoscopy. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 1-min intervals for 15 min after tracheal intubation and for 5 min after skin incision. After intubation, the peak MAP values differed from the preinduction baseline MAP values by 21% +/- 20%, 9% +/- 12%, 1% +/- 13%, -10% +/- 12%, and -15% +/- 13% (mean +/- SD) in the control, N0.5, N1, N2, and N4 groups, respectively. However, the percent change in the pre- to postintubation MAP values (37% to 47%) was similar in all five groups. The highest postintubation HR values were recorded in the N4 group (P < 0.05 versus the other groups). However, the increases in MAP values after skin incision were the least in the N4 group. In conclusion, N1 I.V., administered 2 min before laryngoscopy provides optimal control of arterial blood pressure during the postinduction period. Acute increases in blood pressure during anesthesia are undesirable in patients with preexisting cardiovascular diseases. This double-blind study found that the calcium-channel blocker, nicardipine, 1 mg intravenously 2 min before tracheal intubation maintained hemodynamic stability during the intraoperative period.