# The Effects of Premedication With Three Different Doses of Intravenous Dexmedetomidine on Spinal Anesthesia: A Randomized Comparative Study

## TL;DR

This study compares three doses of intravenous dexmedetomidine during spinal anesthesia and finds higher doses prolong motor block without significant side effects.

## Contribution

The study is the first in the region to compare three bolus doses of intravenous dexmedetomidine during spinal anesthesia.

## Key findings

- Higher doses (0.75 and 1 mcg/kg) significantly prolonged sensory and motor block duration.
- No significant differences in sedation levels, analgesia duration, or adverse effects between doses.
- Doses of 0.75 and 1 mcg/kg provided better block characteristics without compromising hemodynamic stability.

## Abstract

Background: Intravenous dexmedetomidine is one of the commonly preferred techniques for sedation during any regional procedure. However, only a very few studies compared the impact of different bolus doses during spinal anesthesia, and none for our geographical area.

Materials and methods: A total of 60 patients were allocated into either of the three groups (group I, II, III) to receive intravenous dexmedetomidine 0.5, 0.75, and 1 mcg/kg, respectively. The primary outcome was to compare the duration of sensory and motor blockade and the secondary outcomes were the level of sedation, hemodynamic stability, duration of analgesia, and the side effects, if any.

Results: Two-dermatome regression time and the duration of motor block were significantly higher in groups II and III when compared to group I. However, the difference in duration of analgesia, Ramsay sedation scores, bradycardia, and hypotension was statistically insignificant between the groups.

Conclusion: Intravenous dexmedetomidine in doses of 0.75 and 1 mcg/kg significantly prolongs the two-dermatome regression time and duration of the motor block when compared to 0.5 mcg/kg dose. Hence, it is better to titrate the dose between 0.75 and 1 mcg/kg, as the administration of bolus intravenous Dex in doses ranging between 0.75 and 1 mcg/kg appears to provide adequate intraoperative block characteristics while maintaining hemodynamic stability without any significant respiratory depression or other adverse effects.