Comparative analysis of intrathecal dexmedetomidine and fentanyl as an adjuvant to isobaric levobupivacaine in orthopaedic surgery

Abstract

Aim: to compare a combination of isobaric Levobupivacaine with fentanyl and dexmedetomidine for the characteristics of spinal blockade with respect to onset, duration and hemodynamic parameters and side effect. Material and methods: This was a prospective, randomized, and double blinded clinical comparative study conducted in the Department of Anaesthesiology, Jawaharlal Nehru medical college and hospital Bhagalpur, Bihar, India from march 2019 to February 2020. The study population consisted of 150 adult patients who were classified as American Society of Anesthesiologists (ASA) physical status I or II, undergoing elective lower limb orthopaedic surgery under spinal anesthesia. The study participants were randomly divided into three groups.Group A: 0.5% Levobupivacaine Isobaric 2.5ml+ 0.5ml normal saline (total volume is upto 3.0 ml). Group F: 0.5% Levobupivacaine Isobaric 2.5ml + 25mug fentanyl (test solution will diluted with normal saline to total volume of 3.0ml). Group D: 0.5% Levobupivacaine isobaric 2.5ml +5 mcg dexmedetomidine (test solution will diluted with normal saline to total volume of 3.0 ml. Result: The mean time for onset of sensory block was 10.59 ±4.06 min in the saline group and 8.31±2.93 min in the dexmedetomidine group  and 2.21±1.19 min in the fentanyl group. The mean time taken to achieve maximum sensory block in group A was 15.62±4.91 min, in group D was 13.18±3.51 min and in group F it was 5.28±1.92 min so maximum sensory block was achieved earlier in group. Peak level of sensory block attained in the fentanyl group was T4 and the peak level of sensory block in dexmedetomidine group was T6 and in the saline group peak level was T8. So the highest sensory block was attained in the fentanyl group. The mean duration of sensory block in group A was 113.47±7.12min, and in group F was 161.11±12.74min., and in group D was 204.12±6.41 min. Prolong duration occur in the dexmedetomiine group. The prolongation of effect may result from synergism between local anaesthetic and alpha2 adrenoceptor agonist action. The mean onset time of motor block in group A was 11.04±3.98 min, in group D it was 8.97±3.31 min, in group F it was 3.31 ±1.33 min. Onset of motor block occured earlier in the fentanyl group. In the present study there was a significant difference in duration of motor block across the three groups with p value <0.001. In group A mean duration of motor block was 161.04±6.30 min, and in group D was 253.26±6.59 min and in group F it was 186.74±11.64 min. Conclusion:Dexmedetomidine group has longer onset of and duration of sensory block and effective postoperative analgesia and fewer side effect as compared to fentanyl group.

Keywords: Subarachanoid block, Levobupivacaine, anesthesia.