Comparison of dexmedetomidine and idazolam as adjuvants ti intratechal bupivacaine on the duration of block in opium addicted patients candidate for lower extremity surgery

Considering the decreased duration and quality of neuro-axial block in opioids addicted patients, adjuvant medications could improve the anesthetic and analgesic properties of local anesthetics.
fifty six opioids addicted patients candidate for lower extremities surgery were randomly assigned into two groups of Dexmedetomine (5 mcg) and Midazolam (2mg) added to intratechal Bupivacaine. Sensory block, motor block, pain and sedation were evaluated using pin prick test, modified bromage scale, visual analog scale (VAS) and ramsey score respectively. Morphine consumption in 12 hour and 24 hour post operative period were recorded as well.
duration of sensory block was 175 ± 18.9 minute and 147 ± 16.3 minute in Dexmedetomidine and Midazolam groups respectively which was statistically meaningful (p 0.001). Pain in 6 and 12 hour post operative period was meaningfully higher in Midazolam group (p 0.003 and p 0.02 respectively) but not in 24 hour period (p 0.18). Morphine consumption in 24 hour post operative period was much lower in Dexmedetomidine group which was statistically meaningful (p 0.029).
Dexmedetomidine, as an adjuvant medication for spinal anesthesia in opioids addicted patients, can lengthen the sensory block more than Midazolam; moreover, it has less adverse effects andaugments sedation and analgesia.