BACKGROUND: Laryngoscopy and tracheal intubation often provoke an undesirable increase in blood pressure and heart rate. Nicardipine-induced reduction in blood pressure was greater with inhalational anesthetics than nicardipine alone. This study was designed to determine the optimal dose of nicardipine for acceptable hemodnamic change during inhalation with sevoflurane.

METHODS: Eighty ASA physical status 1 patients were randomly allocated into four groups of twenty patients. Tracheal intubation under direct laryngoscopy was performed. After intravenous thiopental 5 mg/kg, vecuronium 0.13 mg/kg 5, 10 or 15µg/kg of nicardipine was given intravenously followed by mask ventilation of three minutes with sevoflurane, nitrous oxide and oxygen. Heart rate and blood pressure were measured at the period of baseline, preintubation, immediately after intubation, 1, 2, 4, 6 and 9 minutes following intubation.

RESULTS: After tracheal intubation, the increase of systolic blood pressure was suppressed significantly by nicardipine 10 and 15µg/kg group compared with the control group. The increase of heart rate was greatest in the nicardipine 15µg/kg group.

CONCLUSIONS: We suggest that the appropriate dose of nicardipine during induction with sevoflurane for attenuation of pressor responses to laryngoscopy and intubation in healthy patients is 10µg/kg.