Efficacy of esmolol administration at different time intervals in attenuating hemodynamic response to tracheal...

Laryngoscopy and endotracheal intubation are known to cause increase in both arterial blood pressure and heart rate. Several strategies have been evolved to blunt the haemodynamic response to tracheal intubation but each method has its own advantages and disadvantages. Esmolol, a cardio selective Beta-1 blocking drug, can alleviate some of these problems. Esmolol, when administered parenterally, exhibits rapid onset and a short duration of action due to its rapid clearance by red blood cell esterases. Hence we conducted the present study to evaluate the efficacy and optimum time of single bolus esmolol administration in attenuating hypertensive- tachycardiac response to laryngoscopy and tracheal intubation.

The randomized double blind prospective study was conducted in 60 patients, in the age group of 20-40 years, of both sexes, belonging to American Society of Anaesthesiologists (ASA) physical status class I or II and scheduled for elective surgery requiring endotracheal intubation and general anaesthesia. The efficacy and optimum time of single bolus esmolol administration in attenuating hypertensive - tachycardiac response to laryngoscopy and tracheal intubation was evaluated. Patients in group I (n = 20) received bolus administration of injection esmolol 1.5 mg/kg intravenously (iv) 90 seconds before intubation; in group II (n = 20) three minutes before intubation and in group III (n = 20) six minutes before intubation.

There was no clinical and statistically significant variation in heart rate in group I and II at different time intervals of the study period but in group III heart rate increased significantly one minute after tracheal intubation. (P < 0.05) One minute after intubation, the increase in systolic, diastolic and mean blood pressure and rate pressure product was statistically significant in group I (P < 0.01) and group III. (P < 0.05) However, in group II increase in systolic blood pressure and rate pressure product was statistically not significant. (P > 0.05)

To conclude, single intravenous bolus dose of esmolol (1.5 mg/kg) is safe and more effective in attenuating haemodynamic response to laryngoscopy and tracheal intubation when administered three minutes prior to intubation.