Abstract PR050

Abstract

Background & Objectives: Both the alpha 2 agonist, clonidine1 and dexmedetomidine2 have been shown to blunt stress response due to laryngoscopy and tracheal intubation (LTI). However clonidine is more often used as an antihypertensive where as dexmedetomidine is preferentially used as a sedative analgesics. Therefore, we wanted to compare the effectiveness of intravenous (IV) clonidine versus dexmedetomidine in controlling heart rate(HR) and blood pressure(BP) responses to LTI and to compare their effects on sedation. Materials & Methods: Sixty American Society of Anesthesiologists physical class 1/2 adult inpatients scheduled for general endotracheal anaesthesia were randomised to receive either clonidine (2 mcg/kg) or dexmedetomidine (1mcg /kg) IV over 10 minute before anaesthesia induction. Haemodynamic (BP and HR) were noted before and after administration of study drugs at five time points. Sedation level was assessed at base line and after study drug infusion. The haemodynamic data obtained were analysed statistically with repeated measure ANOVA with base line data as control value. Results: The hemodynamic were comparable between the groups at base line. There was a fall in HR over time in both the groups but it reached statistical significance only in dexmedetomidine group after study drug infusion (p=0.000) and at 1 minute post intubation (p=0.005).A significant fall in blood pressure was recorded in both the group after study drug administration which was counteracted to some extent by sympathetic stimulation at 1 minute post LTI (P>0.05 compare to base line) but again continued to fall till the end of study period (p=0.000). The maximum percentage fall in systolic blood pressure, diastolic blood pressure, and mean blood pressure after intubation were significantly higher in the clonidine group than in dexmedetomidine group (26 % vs. 22%, 29.4% vs. 26%, and 28.7% vs. 24%, respectively).The patients in dexmedetomidine group tend to be more sedated compared to clonidine group (4.6±0.6 vs.3.80 ±1.2; p=0.002) after study drug infusion. Conclusion: Dexmedetomidine and clonidine attenuated the heart rate response but the return to base line value was quicker in dexmedetomidine. Both drugs resulted in a significant fall in blood pressure. Dexmedetomidine appears to be superior to clonidine because it resulted in lesser magnitude of hypotensive episodes.