EFFECTS OF ALFENTANIL ON THE HEMODYNAMIC AND CATECHOLAMINE RESPONSE TO TRACHEAL INTUBATION

A randomized, placebo-controlled study was conducted in 60 ASA Class I , II, and III patients to determine the dose response of alfentanil in moderating the cardiovascular and catecholamine response to tracheal intubation (INT). Patients were randomly allocated into one of four gr oups to receive either 15 mug/kg alfentanil (A15), 30 mug/kg alfentani l (A30), 45 mug/kg alfentanil (A45), or normal saline (control), given intravenously (IV) before induction of anesthesia. One minute after a dministration of 4.0 mg/kg thiopental and 1.5 mg/kg succinylcholine IV , tracheal intubation was performed using direct laryngoscopy In respo nse to INT, increases in heart rate, systolic blood pressure, and syst emic vascular resistance occurred in the control group. These changes were significantly more than corresponding changes of heart rate, syst olic blood pressure, and systemic vascular resistance in all three alf entanil groups (P < 0.05). In contrast, cardiac index and ejection fra ction decreased moderately in every group during the study period, but there were no differences among groups with respect to either cardiac index or ejection fraction at corresponding times following INT. In t he control group, epinephrine and norepinephrine serum concentrations increased by 152 +/- 52% and 58 +/- 62%, respectively, following INT ( different from A30 and A45, P < 0.05). However, up to a dose of 30 mug /kg (A30), a dose-dependent decrease in the maximum percent changes of both epinephrine and norepinephrine occurred in response to INT. A la rger dose of alfentanil was no more efficacious as the catecholamine r esponse to tracheal intubation was not significantly different when co mparing the A45 and A30 groups. It is concluded that 30 mug/kg is the optimal dose of alfentanil for providing complete attenuation of the c ardiovascular and catecholamine response to tracheal intubation.