Evaluation of esmolol and fentanyl in controlling increases in heart rate and blood pressure during endotracheal intubation.

Laryngoscopy and intubation cause an adrenergic response manifested by tachycardia and hypertension. Various pharmacological agents, including fentanyl, have been administered prior to induction in an attempt to attenuate the adrenergic response but they all have limitations. Esmolol, an ultrashort-acting cardioselective beta blocker, has been administered by infusion to successfully protect surgical patients from the stresses of intubation. The objective of our study was to determine if esmolol would be equally effective when administered in a bolus with and without fentanyl. Forty-four ASA I and II females undergoing elective surgery were randomly divided into four groups and received the following agents prior to intubation: Group 1-esmolol 1 mg/kg and fentanyl 2 micrograms/kg, Group 2-placebo (normal saline), Group 3-esmolol 1 mg/kg and Group 4-fentanyl 3.5 micrograms/kg. Groups 1 and 4, which received fentanyl, demonstrated significantly less elevation in blood pressure. Esmolol appeared to attenuate increases in heart rate. Esmolol has a tissue distribution time of 2 minutes and an elimination half-life of 9 minutes. The window of its availability to the tissues is narrow, and timing of bolus administration is more critical than in administration by infusion. Doses in excess of 1 mg/kg appear to be necessary for effective control of heart rate. However, when used with fentanyl, esmolol provides effective protection against the adrenergic response to laryngoscopy and intubation.