OPTIMAL DOSE OF NICARDIPINE FOR MAINTENANCE OF HEMODYNAMIC STABILITY AFTER TRACHEAL INTUBATION AND SKIN INCISION

To determine the optimal dose of nicardipine (N) for maintenance of he modynamic stability during the postinduction period, we designed a ran domized, double-blind, placebo-controlled, dose-ranging study using fo ur different doses of N administered after a standardized anesthetic i nduction 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 administ ered intravenously (IV) in 2.5 mL of saline over 30 s 2 min before lar yngoscopy. Mean arterial pressure (MAP) and heart rate (HR) were recor ded at 1-min intervals for 15 min after tracheal intubation and for 5 min after skin incision. After intubation, the peak MAP values differe d from the preinduction baseline MAP values by 21% +/- 20%, 9% +/- 12% , 1% +/- 13%, -10% +/- 12%, and -15% +/- 13% (mean +/- SD) in the cont rol, N0.5, N1, N2, and N4 groups, respectively. However, the percent c hange in the pre-to postintubation MAP values (37% to 47%) was similar in all five groups. The highest postintubation HR values were recorde d in the N4 group (P < 0.05 versus the other groups). However, the inc reases in MAP values after skin incision were the least in the N4 grou p. In conclusion, N1 IV, administered 2 min before laryngoscopy provid es optimal control, of arterial blood pressure during the postinductio n period. Implications: Acute increases in blood pressure during anest hesia are undesirable in patients with preexisting cardiovascular dise ases. This double-blind study found that the calcium-channel blocker, nicardipine, 1 mg intravenously 2 min before tracheal intubation maint ained hemodynamic stability during the intraoperative period.