A Study of the Efficacy of Cardiac Antidysrhythmic Drugs in Attenuating Haemodynamic Responses to Laryngoscopy and Endotracheal Intubation in the Black Population

Abstract

Background: Laryngeal, tracheal and bronchial receptors are stimulated by mechanical and chemical irritants during laryngoscopy and endotracheal intubation. That almost always triggers powerful cardiovascular responses. Various attempts have been made to attenuate these responses. The aim of this study was to compare the efficacy and safety of cardiac antidysrhythmic drugs lidocaine, diltiazem and esmolol in the attenuation of cardiovascular responses to endotracheal intubation in the Black normotensive population. Patients and Methods: A randomized controlled trial was conducted in 160 adult patients of ASA physical status I or II undergoing various elective surgeries. The patients were randomly divided into four groups of 40 patients in each group - C, L, D, and E. Group - “C” received no drug (control) as placebo, group -“L” received 1.5 mg kg-1 preservative free lidocaine, group -“D” received 0.2 mg kg-1 diltiazem, and group-“E” received 2mg kg-1 esmolol IV. Group “C”, “D” and “E”, “L” one and two minutes before intubation. Changes in Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP) were measured and then compared within and between groups. Rate Pressure Product (RPP) was calculated and evaluated as well. Patients were also observed for any complications. Result: There was a significant increase in SBP, DBP, HR, MAP and RPP from the base line in control group “C” at 1 minute with onward decreases at 3 and 5 minutes respectively after intubation. Percentage change in haemodynamic variables in groups C, L, D and E at 1 minute are as follows: SBP=23.58%, 11.84%, 9.64% and 9.9%, DBP=18.73%, 18.89%, 11.93% and 10.40%, HR=30.45%, 26.00%, 7.01% and 1.50%, MAP=20.80%, 15.89%, 10.90 and 10.20%; RPP=61.44%, 40.86%, 17.26% and 11.68% respectively. Only patients receiving placebo had increased SBP, DBP, HR, MAP and RPP values after intubation compared with baseline values (p<0.05). Conclusions: Given the difference in the pharmacological mechanisms of these drugs, the prophylactic therapy with 2 mg kg-1 esmolol is significantly more effective and safe for attenuating haemodynamic changes to laryngoscopy and tracheal intubation, without producing increased risk of hypertension in the Black population.