Effect of Low Dose Intravenous Dexmedetomidine with 4% Sevoflurane on Haemodynamic Response during Laryngoscopy and Tracheal Intubation: A Randomised Controlled Study

Introduction: Over the last decade, the use of dexmedetomidine has found favour in obtunding the haemodynamic response during laryngoscopy and tracheal intubation but the use of higher doses has lead to a number of adverse effects.

Aim: To compare the effect of low dose dexmedetomidine (0.5 μg/kg) and 4% sevoflurane (dial setting) with, Normal Saline (NS) and 4% sevoflurane (dial setting) on haemodynamic response to laryngoscopy and intubation.

Materials and Methods: This randomised double blind controlled study was carried out in 60 patients of American Society of Anaesthesiologists (ASA) class I, undergoing elective surgery under general anaesthesia. The patients were allocated to group DX (n=30) and group NS (n=30), who received dexmedetomidine 0.5 μg/kg infusion and NS infusion intravenous (i.v.) respectively, in equal volume over 10 minutes before anaesthesia induction. They were evaluated for the requirement of thiopentone sodium, vecuronium bromide and sevoflurane, total i.v. fluids transfused haemodynamic parameters intraoperatively (pre and post induction) and postoperatively at regular intervals, and side effects.

Results: On statistical comparison, Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Arterial Pressure (MAP) were found to be significantly less in group DX than in group NS with a p-value of <0.05. The total i.v. fluids infused in group NS and DX expressed as mean±Standard Deviation (SD) were 1145.00±228.21 and 1325.00±359.64, respectively. This was statistically significant. Thiopentone requirement was statistically more in group NS with a mean±standard deviation of 249.17±37.99 than in group DX (225.00±38.84). Similarly, sevoflurane requirement was statistically less in the DX group at various time intervals. Ten patients (33%) in group DX required antiemesis, compared to 13 patients (43%) in group NS. Two patients in group NS and three patients in group DX required injection (inj.) atropine to treat bradycardia.

Conclusion: On comparison, a combination of 4% sevoflurane with 0.5 μg/kg dexmedetomidine was more effective in attenuating pressor response than 4% sevoflurane (dial setting) alone, but is associated with minor and manageable risk of bradycardia and hypotension.