A comparison of intrathecal dexmedetomidine, clonidine, and fentanyl as adjuvants to hyperbaric bupivacaine for lower limb surgery: A double blind controlled study

Abstract

Background:Various adjuvants are being used with local anesthetics for prolongation of intraoperative and postoperative analgesia. Dexmedetomidine, the highly selective 2 adrenergic agonist is a new neuraxial adjuvant gaining popularity.Settings and Design:The study was conducted in prospective, double blind manner. It included 120 American Society of Anesthesiology (ASA) class I and II patients undergoing lower limb surgery under spinal anesthesia after approval from hospital ethics committee with written and informed consent of patients.Materials and Methods:The patients were randomly allocated into four groups (30 patients each). Group BS received 12.5 mg hyperbaric bupivacaine with normal saline, group BF received 12.5 mg bupivacaine with 25 g fentanyl, group BC received 12.5 mg of bupivacaine supplemented 30 g clonidine, and group BD received 12.5 mg bupivacaine plus 5 g dexmedetomidine. The onset time to reach peak sensory and motor level, the regression time of sensory and motor block, hemodynamic changes, and side effects were recorded.Results:Patients in Group BD had significantly longer sensory and motor block times than patients in Groups BC, BF, and BS with Groups BC and BF having comparable duration of sensory and motor block. The mean time of two segment sensory block regression was 147 ± 21 min in Group BD, 117 ± 22 in Group BC, 119 ± 23 in Group BF, and 102 ± 17 in Group BS (P > 0.0001). The regression time of motor block to reach modified Bromage zero (0) was 275 ± 25, 199 ± 26, 196 ± 27, 161 ± 20 in Group BD, BC, BF, and BS, respectively (P > 0.0001). The onset times to reach T8 dermatome and modified Bromage 3 motor block were not significantly different between the groups. Dexmedetomidine group showed significantly less and delayed requirement of rescue analgesic.Conclusions:Intrathecal dexmedetomidine is associated with prolonged motor and sensory block, hemodynamic stability, and reduced demand of rescue analgesics in 24 h as compared to clonidine, fentanyl, or lone bupivacaine.

Comparative Study of Bupivacaine alone versus Bupivacaine and Dexmedetomidine for Spinal Anesthesia in Hysterectomies

“…It has an added advantage because, if the sensory block is achieved earlier at T6 dermatome, surgery can also be started earlier in group II as compared with group I. Previously it was also observed that time taken for regression of sensory block to S1 dermatome was delayed with the addition of dexmedetomidine to bupivacaine [12,[16][17][18] , which is in accordance with the present study. Complete motor blockade was achieved earlier and the duration of motor block was more prolonged in group II as compared with group I.…”

“…It has also been observed earlier that addition of low-dose dexmedetomidine to intrathecal bupivacaine does not lead to higher sedation scores [12,13] . Patients remained hemodynamically stable in both groups at all measured intervals for 24 h. Dexmedetomidine as an adjuvant to bupivacaine does not produce any significant hemodynamic changes and vitals remained stable both intraoperatively and postoperatively [16][17][18] . Incidence of side effects and complication was comparable between the two groups, which is in accordance with previous studies [13,19] ..…”

“…Addition of dexmedetomidine to intrathecal bupivacaine produced prolonged postoperative analgesia, and requirement of rescue analgesia in the postoperative period was also decreased [13,[16][17][18][19] . In the present study, no sedative was given during premedication, and thus most of the patients had sedation score in the range of 0 and 1 at all measured intervals in both groups.…”

Intrathecal Dexmedetomidine Alleviates Shivering during Cesarean Delivery under Spinal Anesthesia

“…9) Several studies have shown that use of intrathecal dexmedetomidine as an adjuvant to hyperbaric bupivacaine is associated with prolonged motor and sensory block, while maintaining the hemodynamic stability. [25][26][27] Recent studies have shown that dexmedetomidine may be safely used as an intrathecal supplement in Cesarean delivery. 12,28) Respiratory depression is a potential side effect of dexmedetomidine.…”

“…13,28) The intrathecal doses of dexmedetomidine used in our study were based on previous human studies wherein no neurotoxic effects were documented at these doses. [25][26][27][33][34][35] A limitation of this study was that a doseresponse experiment was not performed to determine the optimal dose of dexmedetomidine required for optimal suppression of shivering, but without causing any significant side effects. In the present study, dexmedetomidine was used as an adjuvant to hyperbaric bupivacaine in a dose of 5 µg as this dosage is reported to be associated with prolonged duration of sensory and motor block without significant side effects.…”