EFFICACY OF INTRAVENOUS ESMOLOL VERSUS LIDOCAINE FOR ATTENUATION OF THE PRESSOR RESPONSE IN NIGERIANS

Laryngoscopy and tracheal intubation are an integral component of airway management and general anaesthesia. Direct stimulation of the pharynx and larynx by the laryngoscope blade and the insertion of an endotracheal tube elicit a sympathetic nervous system response with a reflex consisting of a transient increase in blood pressure, heart rate, and the occurrence of cardiac dysrhythmias referred to as the 'pressor' response. This may be of major clinical significance in patients with pre-existing systemic hypertension, hypertensive heart disease, coronary artery disease, eclampsia, aneurysmal vascular disease and head injury in whom such a change may culminate in perioperative myocardial ischaemia or infarction, cardiac failure, dysrhythmias, cerebrovascular accidents or secondary brain injury.

To evaluate and compare the effects of intravenous lidocaine and esmolol on the pressor response as well as determine the occurrence of complications with the use of either agent in a Nigerian population.

Ninety adult ASA I and II patients undergoing elective non-cardiac surgery under general anaesthesia were randomly allocated to one of 3 groups; group E: 2mg.kg ^-1 esmolol, group L: 1.5mg.kg ^-1 lidocaine and group C: 20mls normal saline 3 minutes before laryngoscopy. Induction of anaesthesia was standardized for all patients. Heart Rate, Systolic Blood Pressure, Diastolic Blood Pressure, Mean Arterial Pressure and Rate Pressure Product were recorded at baseline, immediate post, 1, 3, 5 and 10 minutes after intubation.

Mean heart rate increased by 19.1%, 25.7%, and 41.4%, SBP increased 13.3%, 21.6% and 26.9%, MAP by 12.2%, 19.1% and 30.2%, RPP by 28.1%, 45.8% and 78.7% in groups E, L and C respectively post intubation. There were no complications attributable to the use of either agent.

Intravenous esmolol 2mg.kg^-1 given prior to laryngoscopy is more effective than intravenous lidocaine 1.5mg.kg^-1 in significantly attenuating the haemodynamic changes associated with pressure response to laryngoscopy and endotracheal intubation in normotensive patients from a Nigerian population.