Effect of Adding Dexmedetomidine versus Fentanyl to Intrathecal Bupivacaine on Spinal Block Characteristics in Gynecological Procedures: A Double Blind Controlled Study

Abstract

Problem statement: The purpose of this study was to evaluate the onset and duration of sensory and motor block as well as operative analgesia and adverse effects of Dex Metedo Midine (DXM) or fentanyl given intrathecally with plain 0.5% bupivacaine for spinal anesthesia. Approach: seventy six patients classified as American Society of Anesthesiologists (ASA) status I, II and III scheduled for vaginal hysterectomy, vaginal wall repair and tension free vaginal tape were prospectively studied. Patients were randomly allocated to receive intrathecally either 10 mg isobaric bupivacaine plus 5 µg dexmetedomidine (group D n = 38) or 10 mg isobaric bupivacaine plus 25 mg fentanyl (group F n = 38), the onset time to reach peak sensory and motor level, the regression time for sensory and motor block, hemodynamic changes, and side effects were recorded. Results: Patients in group D had significant longer sensory and motor block times than patients in group F. the mean time of sensory regression to S1 was 274±73 min in group D and 179±47 min in group F (P < 0.001). The regression time of motor block to reach modified Bromage 0 was 240±60 min in group D and 155±46 min in group F (P< 0.001). The onset times to reach T10 dermatome and to reach peak sensory level as well as onset time to reach modified Bromage 3 motor block were not significantly different between the two groups. Conclusion: In women undergoing vaginal reconstructive surgery under spinal analgesia, 10 mg plain bupivacaine supplemented with 5 µg dexmetedomidine produces prolonged motor and sensory block compared with 25 µg fentanyl.

A comparison of intrathecal dexmedetomidine and clonidine as adjuvants to hyperbaric bupivacaine for gynecological surgery

“…They produce analgesia by the depressing release of C-fi ber transmitters and by hyperpolarization of post-synaptic dorsal horn neurons. 4,5,11 The complementary action of local anesthetics and alpha2 adrenoreceptor agonist accounts for their profound analgesic properties. The prolongation of motor block of spinal anesthetics may be the result of binding of alpha2 adrenoreceptor agonists to the motor neurons in the dorsal horn.…”

“…[4][5][6][7] Where gradually evolving studies can build the evidence for its safe use in central neuraxial blocks.…”

“…2 Based on earlier human studies, intrathecal 5 mcg dexmedetomidine would produce longer duration of analgesic effect in spinal anesthesia with minimal side effects. [4][5][6][7] Where gradually evolving studies can build the evidence for its safe use in central neuraxial blocks. ³ We explore its usefulness and also compare this new alpha2 adrenergic agonist with the previously established and widely used adjuncts.…”

Efficacy of premixed versus sequential administration of dexmedetomidine as an adjuvant to intrathecal hyperbaric bupivacaine in lower limb surgery

“…Though the mechanism of this effect is not clear, it is proposed to act by binding to presynaptic C fibres, thus depressing the release of neurotransmitters, and by hyperpolarisation of postsynaptic dorsal horn neurons. 9,10 It is also shown to reduce the incidence of shivering in the postoperative period and the post-anaesthetic analgesic requirement. Similarly, studies have been done to determine the optimal intrathecal dose of dexmeditomidine.…”

“…Many studies [8][9][10] have shown that dexmeditomidine, when used as an intrathecal adjuvant, decreases postoperative analgesic requirement. This analgesic sparing effect was more pronounced in group S as compared with group P as requirement for rescue analgesic was significantly less in group S during the first six hours postoperatively.…”