Clinical Investigation A Comparative Study of Oral Pregabalin and Clonidine for Attenuation of Hemodynamic Responses to Laryngoscopy and Tracheal Intubation

Background: Airway instrumentation by direct laryngoscopy and tracheal manipulation are powerful noxious stimuli causing adverse hemodynamic responses. This study evaluates and compares oral clonidine and pregabalin premedication on the hemodynamic responses following laryngoscopy and tracheal intubation and to assess the adverse events associated with these drugs. Materials & Methods: Sixty patients of ASA Grade I or II and aged between 18-60 years, of either sex, who were posted for elective surgeries under general anaesthesia were selected. The patients were randomly divided into 2 groups of 30 each where Group C received 200μg Clonidine and group P 150mg Pregabalin 90 mins before surgery. After three mins of pre-oxygenation with 100% oxygen, pre-medication given was 5μg/kg of IV glycopyrolate and 2.5μg/ kg IV Fentanyl was given for analgesia. Patients were induced with IV Thiopentone 5mg/kg followed by IV Suxamethonium 2mg/kg for intubation. Anaesthesia was maintained with Nitrous Oxide, Oxygen and Isoflurane. Muscle relaxation was achieved with IV Vecuronium 0.1mg/kg (loading dose) and 0.02mg/kg for maintenance dose. During laryngoscopy and endotracheal intubation the heart rate, systolic blood pressure, diastolic blood pressure and mean blood pressure were recorded at 0,1,3,5 and 10 mins. Statistical difference between the two groups were analyzed using student’s ‘t’ test. Results: Attenuation of increase in BP was better in group P whereas tachycardia response was better attenuated in group C and sedation was more commonly obtained in Group P which were statistically significant. Conclusions: Both Pregabalin and Clonidine successfully attenuated the hemodynamic response to laryngoscopy and tracheal intubation. Pregabalin better attenuates pressor response and clonidine better attenuates tachycardia response.