Attenuation of Hemodynamic Responses to Laryngoscopy and Endotracheal Intubation with Dexmedetomidine: A Comparison Between Intravenous and Intranasal Route.

Background: Dexmedetomidine is a highly selective, a2 adrenoreceptor agonist drug, which has sedative, analgesic and anxiolytic property without any respiratory depressive action. Dexmedetomidine causes post synaptic activation of a2 adrenoreceptors in the CNS resulting in hypotension and bradycardia through sympatholysis. Preoperative administration of dexmedetomidine can successfully attenuate the laryngoscopic stress response via intravenous, intramuscular or intranasal routes. Material and Methods: 80 adult patients of either sex between the age group of 18 to 60 years of ASA-I and ASA-II undergoing elective major surgeries were divided randomly into two groups of 40 patients each. Group - D(IV) received intravenous dexmedetomidine (0.50µg/kg) diluted in 50 ml syringe with normal saline through an infusion pump over 40 min before induction. Group - D(IN) received intranasal dexmedetomidine (1 µg/kg) in undiluted form which was prepared from parenteral preparation (100µg/ml). Intranasal drug dripped into both nostrils in equal volume using a 1 ml syringe in supine head down position about 40 min before induction. Result: The mean baseline heart rate in group D(IV) was (82.73 ± 5.95) per minute and it decreased to (80.33 ± 5.93) per min at 10 minutes time interval but was statistically insignificant. The p-value became statistically significant at 30minute (0.024) and 40-minute (0.011) time interval in pre induction period. During laryngoscopy and intubation time interval Mean heart rate was (87.18 ±5.54) beats/minute in group D(IV) and (90.95±6.02) beats/minute in group D(IN) and the p-value in intergroup comparison came out to be 0.004 which was statistically significant. Conclusion: Dexmedetomidine drug when given in group D(IN) through intranasal route at a dose of 1 µg/kg body weight forty minutes before induction of anesthesia produced similar haemodynamic changes as when given through intravenous route as infusion in group D(IV) at a dose of 0.5 µg/kg body weight in patients undergoing major surgeries under general anaesthesia. [ABSTRACT FROM AUTHOR]