A Comparative Study of Intrathecal Dexmedetomidine and Fentanyl as Adjuvants to Bupivacaine for Lower Abdominal Surgeries

Abstract

Various adjuvants have been used with local anesthetics in spinal anesthesia to improve the quality of block and to provide prolonged postoperative analgesia. Dexmedetomidine, the new highly selective α2-agonist drug, is now being used as a neuraxial adjuvant. AIM: The aim of this study was to evaluate the onset and duration of sensory and motor block, hemodynamic effect, postoperative analgesia, and adverse effects of dexmedetomidine or fentanyl given intrathecally with hyperbaric 0.5% bupivacaine. METHODOLOGY: Fifty patients classified in American Society of Anesthesiologists classes I and II scheduled for lower abdominal surgeries were included in this prospective cohort study at Amala Institute of Medical Sciences. Patients received either 15 mg hyperbaric bupivacaine plus 25 μg fentanyl (group 1, n = 25) or 15 mg hyperbaric bupivacaine plus 5 μg dexmedetomidine (group 2, n = 25) intrathecally. RESULTS: Patients in dexmedetomidine group (2) had a significantly longer duration of motor and sensory block than patients in fentanyl group. (1) The mean time regression of motor block to reach Bromage 0 was 176.2±5.71 min in dexmeditomidine group and 166.36±5.97 min in fentanyl group (P<0.05). Duration of analgesia was 239.52±9.05 min in Dexmeditomidine group and 189.96±5.35 min in fentanyl group (p<0.05). A significant decrease in heart rate was noted in dexmedetomidine group. CONCLUSION: Intrathecal dexmedetomidine is associated with prolonged duration of analgesia and motor block along with significant decrease in heart rate.

A Comparison between Intrathecal Dexmedetomidine and Fentanyl as an Adjuvant to Hyperbaric Bupivacaine in Spinal Anaesthesia for Lower Limb Surgeries - A Double Blind Controlled Study

“…Similar results were also noted by Kishore et al, [19] Mehendru V et al, [18] Gupta R et al [21] Motor block onset time to modified Bromage 3 was also observed but no statistically significant differences were found. Similar findings were noted by Gupta et al, Mehendru V et al [18] and Kishore et al [19] Heart rate (HR), mean arterial blood pressure (MAP) at baseline, just after dural puncture, at 3 min intervals till first 15min, then at 5min intervals till 90 min were compared. Though there was theoretical possibility of lowering of HR [22] , difference of HR was not statistically significant at all the above intervals.…”

“…Similarly for MAP, no statistical significant difference was observed in our study between these two groups in above mentioned intervals. Similar observation was also noted by Mahendru V et al, [18] Kishore et al, [19] and Gupta R et al [21] Two segment sensory regression from highest sensory block level, sensory block regression to S1 level and motor block regression to modified Bromage 0 was compared between this two groups. The differences for all this three parameters were very much statistically significant (P<0.0001).…”

“…Similar Gupta et al, Mehendru V et al [18] Heart rate (HR), mean arterial blood pressure (MAP) baseline, just after dural puncture, 15min, then at 5min intervals at 5min intervals at till Though there was theoretical possibility [22] , difference of HR was not statistically the above intervals. Similar results Khan et al, [1] Suresh et al, [23] and Statistically significant lowering Licensed Under Creative Commons Attribution CC BY [14] , Mehendru V et al [18] , Kishore et al [19] , ] , Safari et al [20] , Suresh et al [23] , Sunil BV et al [24] , Nayagam HA et al [25] and Routrey et al [26] The mechanism by which intrathecal α adrenoreceptor agonists prolong the motor and sensory block of local anaesthetics is at the best, speculative. It may be an additive or synergistic effect secondary to the different mechanisms of action of the local anaesthetics and intrathecal α adrenoreceptor agonists.…”

“…These finding was similar with Mahendru V et al [18] , who observed no difference in the onset time in patients receiving dexmedetomidine (10.3 ± 3.3 min) and fentanyl (9.6 ± 2.9) as adjuvant to hyperbaric bupivacaine and fentanyl (7.4 ± 3.3 min) as adjuvants to isobaric bupivacaine (P = 0.95). Similarly, no significant differences in sensory onset time among study groups were also by observed by Gupta R et al, [12] Kishore et al [19] and Safari et al [20] The onset times observed in the study conducted by AI Ghanem et al [10] were relatively shorter by dexmedetomidine than those observed by us which can be attributed by difference in patient positioning (lithotomy vs supine in our study).…”

“…Similar results were also observed by Khan et al, [1] Suresh et al, [23] and Mahendru V et al [18] . Statistically significant lowering of HR was observed by Kishore et al [19] in dexmedetomidine group compared to fentanyl group which may be attributed by their greater volume of intrathecal drugs (total 3.5 ml compared to 3 ml in our study). Similarly for MAP, no statistical significant difference was observed in our study between these two groups in above mentioned intervals.…”