A Randomized Controlled Trial to Compare the Efficacy of Intravenous Dexmedetomidine and Clonidine as Adjuvants to Low Dose Opioid in Attenuation of Hemodynamic Response to Laryngoscopy and Tracheal Intubation.

Increase in sympathetic activity as a result of cardiovascular stress response to laryngoscopy can be detrimental to the patient. The primary objective is to compare intravenous dexmedetomidine and clonidine as adjuvants to low dose opioid (fentanyl) for attenuation of hemodynamic response to laryngoscopy and tracheal intubation. The secondary objectives are to compare the perioperative dose requirement of fentanyl and thiopentone, to compare the duration of postoperative analgesia, and to look for side effects in all three groups. This randomized controlled trial was performed in a tertiary care hospital in North India from November 2012 to April 2014. One hundred twenty (120) patients (ASA I or II) posted for elective surgery under general anesthesia. Group D received intravenous dexmedetomidine (1μg/kg) with intravenous fentanyl (1μg/kg), Group C received intravenous clonidine (1μg/kg) with intravenous fentanyl (1μg/kg) and Group F received intravenous fentanyl (2μg/kg). Heart rate and mean arterial pressure were recorded at baseline, after study drug at 5, 10 & 15 minutes, after induction, intubation (0 min) and 1, 3, 5, 10, 15 minutes after intubation. The required perioperative doses of thiopentone and fentanyl, and time to first rescue analgesia given in postoperative period were also noted. One way ANOVA and Repeated Measures ANOVA followed by multiple comparisons (if applicable) were used for data analysis. P value <0.05 was considered statistically significant. The rise in HR and MAP at laryngoscopy and intubation was found to be less in clonidine group as compared to fentanyl group and dexmedetomidine was able to abolish this rise completely. The requirement of thiopentone and fentanyl were significantly least in dexmedetomidine group and the duration of time to first rescue analgesia was significantly prolonged in clonidine group. Intravenous fentanyl (2μg/kg) failed, addition of clonidine to fentanyl was able to partially blunt it, but the addition of dexmedetomidine to fentanyl completely abolished the hemodynamic response to laryngoscopy and intubation.