Effects of calcium channel blockers on circulatory response to tracheal intubation in hypertensive patients: nicardipine versus diltiazem.

We studied the circulatory responses to laryngoscopy and tracheal intubation in 37 hypertensive patients who received nicardipine 30 micrograms.kg-1 iv (Group N, n = 12), diltiazem 0.3 mg.kg-1 (Group D, n = 12) or saline placebo (Group C, n = 13) 60 sec before the initiation of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg.kg-1 iv, and succinylcholine 2 mg.kg-1 iv was used to facilitate tracheal intubation after precurarization with vecuronium 0.02 mg.kg-1 iv. In patients in Group C heart rate (HR) increased from 79 +/- 14 (baseline) to 110 +/- 12 (P < 0.05) associated with tracheal intubation; mean arterial pressure (MAP) increased from 116 +/- 8 to 140 +/- 77 (P < 0.05) and rate-pressure product (RPP) increased from 13385 +/- 2393 to 21251 +/- 3883 (P < 0.05). The changes from baseline values in HR and RPP after tracheal intubation in Group D were less than those in Groups C and N (P < 0.05). The increase in MAP following tracheal intubation in Groups N and D was lower than that in Group C (P < 0.05). We conclude that, compared with nicardipine, administration of diltiazem iv is associated with less circulatory response to tracheal intubation in hypertensive patients.