Comparison of Two Different Doses of Dexmedetomidine as an Adjuvant to Intrathecal Bupivacaine in Patients Undergoing Femur Surgery.

ABSTRACT

Background: Duration of action of local anaesthetic is an important limiting factor in spinal anaesthesia. Dexmedetomidine, selective α 2- agonist has been recently used in addition to other adjuvants to prolong the duration of intrathecal local anaesthetics. Aim: To compare two different doses of dexmedetomidine added to heavy bupivacaine 0.5% intrathecally for femur surgeries. Methods: In this prospective double blind trial, one hundred and twenty patients were randomly allocated into two groups, D1 and D2. Group D1 received 12.5 mg 0.5% hyperbaric bupivacaine and 5 μg dexmedetomidine. Group D2 received 12.5 mg 0.5% hyperbaric bupivacaine and 10 μg dexmedetomidine. Results: Sensory and motor block were comparable in both groups in terms of characteristics like the highest level of sensory block achieved, time to achieve maximum sensory block and time of two segment regression, time to achieve maximal motor block and duration of regression to Bromage scale 0. However time of first analgesic request and total analgesic requirement were significantly reduced by increasing intrathecal dose of dexmedetomidine to 10 μg without any undesirable effects. Conclusion: Intrathecal dose of 10 μg dexmedetomidine provided an increased duration of sensory compared to 5μg dosing, with no significant increase in duration of motor blockade or the incidence of hypotension, bradycardia and any other undesirable side-effects.