Comparison of esmolol and labetalol, in low doses, for attenuation of sympathomimetic response to laryngoscopy and intubation.

OBJECTIVE: The present study compared the efficacy of esmolol and labetalol, in low doses, for attenuation of sympathomimetic response to laryngoscopy and intubation.

DESIGN: Prospective, randomized, placebo controlled, double-blinded study.

SETTING: Operation room.

PATIENTS AND METHODS: 75 ASA physical status I and II adult patients, aged 18-45 years undergoing elective surgical procedures, requiring general anesthesia and orotracheal intubation.

INTERVENTIONS: Patients were allocated to any of the three groups (25 each)-Group C (control)10 ml 0.9% saline i.v. Group E (esmolol) 0.5 mg/kg diluted with 0.9% saline to 10 ml i.v. Group L (labetalol) 0.25 mg/kg diluted with 0.9% saline to 10 ml i.v. In the control group 10 ml of 0.9% saline was given both at 2 and 5 min prior to intubation. In the esmolol group 0.5 mg/kg of esmolol (diluted with 0.9% saline to 10 ml) was given 2 min prior and 10 ml of 0.9% saline 5 min prior to intubation. In the labetalol group 10 ml of 0.9% saline was administered 2 min prior and 0.25 mg/kg of labetalol (diluted with 0.9% saline to 10 ml) 5 min prior to intubation. All the patients were subjected to the same standard anesthetic technique.

MEASUREMENTS: Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded prior to induction, at time of intubation and 1, 3, 5, and 10 min after intubation. Mean arterial pressure (MAP) and rate pressure product (RPP) were calculated. Abnormal ECG changes were also recorded.

RESULTS: Compared to placebo and esmolol (0.5 mg/kg), labetalol (0.25 mg/kg) significantly attenuated the rise in heart rate, systolic blood pressure, and RPP during laryngoscopy and intubation. However, the difference was not statistically significant among the values for DBP and MAP.

CONCLUSION: In lower doses, labetalol (0.25 mg/kg) is a better agent than esmolol (0.5 mg/kg) in attenuating the sympathomimetic response to laryngoscopy and intubation.