Effects of nicardipine on the circulatory responses to tracheal intubation in normotensive and hypertensive patients.

This study was undertaken to examine the effects of nicardipine on circulatory responses to laryngoscopy and tracheal intubation in normotensive (n = 39) and hypertensive (n = 36) patients. Laryngoscopy and tracheal intubation were performed after induction of anaesthesia with thiamylal, followed by administration of intravenous saline or nicardipine 20 or 30 micrograms.kg-1 and suxamethonium. Blood pressure and heart rate were recorded, and rate-pressure product was calculated. Nicardipine 20 and 30 micrograms.kg-1 prevented the increase in mean arterial pressure after intubation in normotensive and hypertensive patients (p less than 0.01 compared with saline). The changes in heart rate after intubation were significantly greater in normotensive patients than in hypertensive patients when 20 or 30 micrograms.kg-1 of nicardipine was given (p less than 0.05 and p less than 0.01 respectively). Rate-pressure product increased significantly (p less than 0.01) after intubation in normotensive patients whether nicardipine was administered or not, but the increase was suppressed completely by nicardipine 20 or 30 micrograms.kg-1 in hypertensive patients. We conclude that nicardipine is effective in preventing the circulatory responses to laryngoscopy and tracheal intubation in hypertensive patients.