This randomized controlled trial evaluated the effect of adding intrathecal dexmedetomidine (10 µg) to hyperbaric bupivacaine (11 mg) for spinal anesthesia in patients undergoing lower limb amputation. Thirty patients (ASA I-III) scheduled for elective supra- or infracondylar amputation were randomly allocated to two groups: Control Group (n=15) received hyperbaric bupivacaine 11 mg plus saline 0.9%, and Experimental Group (n=15) received hyperbaric bupivacaine 11 mg plus dexmedetomidine 10 µg. Primary outcomes were duration of motor and sensory neuraxial block and postoperative analgesia at 48 hours. As a prespecified exploratory secondary outcome, incidence of acute neuropathic pain was assessed using the DN4 screening tool at 48 hours. The study was conducted at the Hospital Regional de Alta Especialidad Dr. Juan Graham Casasus, Villahermosa, Tabasco, Mexico, from April to October 2025. Ethics approval was obtained from the Institutional Review Board (CEI/JGC/C02-25) prior to patient enrollment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
30
Hyperbaric bupivacaine 0.5% 11 mg plus saline 0.9% 0.1 ml administered intrathecally. Total volume 2.3 ml.
Hyperbaric bupivacaine 0.5% 11 mg plus dexmedetomidine 10 µg administered intrathecally. Total volume 2.3 ml.
Hospital Regional de Alta Especialidad Dr. Juan Graham Casasus
Villahermosa, Tabasco, Mexico
Time to First Analgesic Rescue
Time in hours from spinal block to first postoperative analgesic rescue request.
Time frame: 48 hours postoperatively
Proportion Requiring Analgesic Rescue
Proportion of patients requiring at least one analgesic rescue dose during the postoperative period.
Time frame: 48 hours postoperatively
Heart Rate
Heart rate measured in beats per minute during the first 4 hours post-block.
Time frame: 4 hours postoperatively
Duration of Motor Block
Duration of motor block assessed by modified Bromage scale (0-3, higher scores indicate greater motor block). Measured at multiple timepoints through 48 hours postoperatively.
Time frame: 48 hours postoperatively
Duration of Sensory Block
Duration of sensory block assessed by Hollmen scale. Measured at multiple timepoints through 48 hours postoperatively.
Time frame: 48 hours postoperatively
Incidence of Acute Neuropathic Pain
Incidence of acute neuropathic pain assessed by DN4 screening tool (0-10, score ≥4 indicates neuropathic pain component). Reported as exploratory secondary outcome.
Time frame: 48 hours postoperatively
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