Dexmedetomidine Versus Fentanyl as Adjuvants to Intrathecal Bupivacaine in Knee Arthroscopy. A Randomized Controlled Trial

Introduction: Knee arthroscopy can be safely performed with neuraxial anaesthesia. Many adjuvants were added to local anesthetics to prolong the duration of the block. The earliest adjuvants were opioids followed by the α2 agonist clonidine. Dexmedetomidine is a newly introduced α2 agonist with promising characteristics in this respect. Methods: 30 patients were included in the study devided into two groups. Group D: Received 2.5ml hyperbaric bupivacaine 0.5% plus 5μg dexmedetomidine and Group F: Received 2.5ml hyperbaric bupivacaine 0.5% plus 25μg fentanyl. Primary outcome was the time to two segment regression in the sensory block. Results: The time to two segment regression was significantly longer in the Dexmedetomidine group. The highest sensory level and time to reach it was comparable between the two groups as well as the rate of side effecs. Conclusion: Intrathecal dexmedetomidine as an adjuvant to bupivacaine seems to be a good alternative to fentanyl for knee arthroscopy due to its intrathecal anesthetic and analgesic properties with minimal side effects.