Attenuation of the pressor response to laryngoscopy and tracheal intubation with intravenous verapamil

Abstract

This study was undertaken in surgical patients in order to evaluate the effects of intravenous verapamil on the circulatory responses to laryngoscopy and tracheal intubation. Laryngoscopy for tracheal intubation was initiated 1 min after thiamylal 5 mg .cntdot. kg-1 and succinylcholine 1.5 .mu.g .cntdot. kg-1 in the control group (n = 21). The verapamil group (n = 23) received intravenous verapamil 0.1 mg .cntdot. kg-1 immediately after thiamylal-succinylcholine administration. The resulting changes in mean arterial pressure (MAP) and heart rate (HR) were continuously measured. Compared with control group, MAP increased less in response to laryngoscopy and tracheal intubation (56 .+-. 13% versus 25 .+-. 15% above baselines, P < 0.01) and returned toward baseline sooner in patients receiving verapamil. For hypertensive patients, MAP increases from baseline after intubation were 18 .+-. 9% in the verapamil group, and 53 .+-. 14% in the control group, respectively (P < 0.001). Increases in HR response to laryngoscopy for intubation were comparable in both groups. We conclude that intravenous verapamil is effective in reducing pressor responses during endotracheal intubation, especially in hypertensive patients.