Comparison of Oral Labetolol and Oral Pregabalin in Attenuating Pressor Response to Endotracheal Intubation in Patients undergoing Mastoidectomy under General Anaesthesia- A Randomised Control Study

Introduction: Direct laryngoscopy and tracheal intubation provoke stress response side-effects in the form of hypertension, tachycardia, and dysrhythmia which are long-standing concerns for anaesthetists. Various drugs and techniques have been tried over the last few decades to avoid these side-effects but none are ideal. Oral labetalol through years of study has proven its efficacy in attenuation of these haemodynamic responses. Oral pregabalin is also effective in this regard, however, there are no studies comparing their relative efficacies. In the present study, we have compared these two drugs i.e., oral pregabalin and oral labetalol with satisfactory results.

Aim: To compare the efficacy of preoperative oral pregabalin with that of oral labetalol in controlling the haemodynamic responses to laryngoscopy and intubation in patients undergoing mastoidectomy under general anaesthesia.

Materials and Methods: This randomised control study was conducted in Era Medical College and Hospital, Lucknow, Uttar Pradesh, India, over the period of 18 months from June 2019 to December 2020. Total 90 American Society of Anesthesiologists (ASA) Grade I and II patients aged 18-50 years of either gender scheduled to undergo elective mastoidectomy surgery under general anaesthesia were enrolled in this study. Thirty patients received tablet oral pregabalin 150 mg, 30 received oral labetalol tablet 200 mg while the remaining 30 received placebo in form of a multivitamin tablet. Drugs were given one hour before propofol induction. Heart rate, Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Arterial Pressure (MAP) were recorded preoperatively, 60 minutes after administration of study drug, during laryngoscopy and intubation, and at 1, 2, 5, and 10 minutes after intubation. At the end of the study, results were represented as (mean±SD) and percentage changes and compared using the student’s t-test.

Results: Mean age of group I was 25.53±8.51 years, group II was 24.80±8.19 years and group III was 26.03±9.10 years. While conducting an intergroup comparison of the two study drugs oral pregabalin showed a greater control in haemodynamic parameters like SBP (at t=2 min, p-value <0.001, t=5 min, p-value 0.003), DBP {at t=Induction (p-value <0.001), 1 min (p-value=0.010), 2 min (p-value <0.001), 5 min (p-value <0.001)} and MAP {at t=Induction (p-value <0.001), 1 min (p-value=0.006), 2 min (p-value <0.004), 5 min (p-value=0.033)} than oral labetalol. Intergroup difference in heart rate was not appreciable between the two drugs except at 60 minutes and baseline after administration (p-value <0.001).

Conclusion: The study showed that though both pregabalin and labetalol were effective in controlling postintubation haemodynamic changes, attenuation of all immediate postintubation haemodyn-amic changes except heart rate was more effective with pregabalin as compared to labetalol. The difference in attenuation of heart rate was not significant between pregabalin and labetalol.