Comparison of dexmedetomidine and buprenorphine as an adjuvant to bupivacaine during spinal anaesthesia for tibial interlocking nailing surgeries

Abstract

INTRODUCTIONSpinal anesthesia is the choice of regional anesthesia technique for surgeries on the lower limbs, as it preserves consciousness, spontaneous breathing at the same time provides for analgesia and muscle relaxation.1,2 These advantages can be minimized when local anaesthetic alone is used for spinal anaesthesia, as it provides for shorter duration of action.2,3 Many adjuvants like fentanyl, buprenorphine have been tried and are effective to prolong the anaesthetic effects.2,4 Dexmedetomidine, is a selective alpha2-adrenoreceptor agonist has been used for analgesia and intravenous sedation in intensive care unit. 5,6 When used for spinal anasethesia, it acts on the ABSTRACT Background: Buprenorphine is being used as an adjuvant to local anaesthetic for spinal anaesthesia since long. Dexmedetomidine is a new drug which has got alpha 2 agonistic property, and is being tried for spinal anesthesia along with bupivacaine in recent times. Settings and Design: This study was conducted in a prospective, randomized, controlled and double-blind manner. The study included ninety American Society of Anaesthesiologists class I and II patients undergoing tibial interlocking nailing surgeries under spinal anaesthesia. Methods:The patients were randomly divided into three groups (n=30 each) by closed envelope technique. Patients in group 1 received 15 mg of 0.5% hyperbaric bupivacaine, group 2 received 15 mg of 0.5% hyperbaric bupivacaine with 30μg of buprenorphine, and group 3 received 15 mg of 0.5% hyperbaric bupivacaine with 5μg dexmedetomidine for spinal anesthesia. The duration of motor and sensory blockade and any adverse events were recorded. Data were analysed using Chi-square test or Fisher's exact test for categorical data and analysis of variance for continuous data. A value of P<0.05 was considered as statistically significant. Results: In our study the subjects in group 3 (dexmedetomidine) group had significantly longer period of motor blockade (240±20min) and sensory blockade (180±22.2min) compared to other groups, which is statistically significant (P=0.0001 and P= 0.006 respectively). The time to first request of analgesic in the post-operative period was also longer (240±30.2min) in dexmedetomidine group when compared with other groups (P=0.0001). There were no untoward complications (hypotension, sedation) in any groups. Conclusions:We concluded that dexmedetomidine (5μg) with bupivacaine for spinal anesthesia gives significantly longer duration of sensory and motor blockade, than buprenorphine (30μg) with bupivacaine for spinal anaesthesia.