Combined spinal epidural anesthesia (CSE) with bupivacaine alone is not sufficient to cover pain sequel during lower limb surgeries. Previous studies used addition of either Nalbuphine or dexmedetomidine to bupivacaine in epidural anesthesia giving a good result in pain control. In this study the investigators will evaluate and compare the addition of either Nalbuphine or dexmedetomidine to bupivacaine in epidural anesthesia to evaluate the analgesic efficacy of either drug.
Surgical patients need adequate and effective intraoperative anesthesia and postoperative analgesia. Neuroaxial block including lower limb spinal and epidural blocks have a long history of effective anesthesia and lower limb pain relief. Spinal anesthesia is a simple method requiring small dose of local anesthetic agent to give immediate and effective sensory and motor block. But one of its major side effects is hypotension and difficulty in controlling the level of the block \[1\]. Meanwhile, epidural anesthesia is a safe, well-practiced, not expensive neuroaxial block technique that provides intraoperative anesthesia and postoperative analgesia. So, the combined spinal epidural block (CSE) aims to achieve intense sensory and motor anesthesia and prolong the duration of analgesia intraoperative extending to postoperative period \[2\]. Neuroaxial anesthesia and analgesia provide perfect analgesic effect by inhibiting nociceptive transmission from peripheral to central neuronal system, but this advantage limited by short half-life of the current local anesthetics. Bupivacaine is a local anesthetic which belongs to amide group of anesthetic agents that has been widely used for local infiltration, peripheral nerve block, spinal and epidural anesthesia and despite relatively long duration of action, still has insufficient time for postoperative analgesia \[3\]. Several neuroaxial adjuvants such as (opioids, dexamethasone, magnesium sulphate, midazolam and dexmedetomidine) can be added to local anesthetics to prolong its duration of anesthesia and decrease the dose requirement of local anesthetics \[4\]. Nalbuphine, a derivative of 14-hydroxy morphine is a strong analgesic with mixed kappa agonist and µ antagonist properties. Its potency is equal to morphine, but exhibits a ceiling effect on respiratory depression. It has the potential to maintain and enhance µ-opioid based anesthesia while simultaneously mitigating the µ-opioid side effects \[5\]. Dexmedetomidine is an imidazole compound. It is a highly selective α-2 adrenergic agonist with an affinity 8 times more specific when compared to clonidine. It has sedative, sympatholytic and analgesic effects that blunt cardiovascular responses both intraoperative and in the perioperative period. Patients remain calm and sedated when undisturbed but arouse readily with stimulation \[6\]. Dexmedetomidine causes manageable hypotension and bradycardia, but the striking feature of this drug is the lack of opioid-related adverse effects like respiratory depression, pruritis, nausea, and vomiting \[7\].
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
23
Surgery will be started under spinal anesthesia. When sensory block regress to T12 dermatome Epidural bolus dose will be given epidural bolus dose of 12ml (10ml 0.25% bupivacaine + 2ml normal saline) The onset of sensory blockade injected epiduraly with maximal cephalic spread will be assessed by bilateral pinprick method along the midclavicular line, every 5 min for 30 min and then every 30 min. top up dose of 8ml will be given postoperative (6ml 0.25% bupivacaine + 2ml normal saline).
Surgery will be started under spinal anesthesia. When sensory block regress to T12 dermatome Epidural bolus dose will be given epidural bolus dose of 12ml (10ml 0.25% bupivacaine + 100µg dexmedetomidine in 2ml volume) The onset of sensory blockade injected epiduraly with maximal cephalic spread will be assessed by bilateral pinprick method along the midclavicular line, every 5 min for 30 min and then every 30 min. top up dose of 8ml will be given postoperative (6ml 0.25% bupivacaine + 20µg dexmedetomidine in 2ml volume).
faculty of medicine, Zagazig university
Zagazig, Elsharqya, Egypt
Duration of epidural analgesia
time elapsed from epidural injection of LA until VAS score (≥3)
Time frame: within 24 hour postoperative
Maximum level of sensory blockade
the maximum sensory dermatome level after 30 min of administering the local anesthetic in the epidural space
Time frame: after 30 min of administering the local anesthetic in the epidural space
number of top up doses required
When sensory block regress to T12 dermatome Epidural bolus dose will be given
Time frame: within 24 hour postoperative
assessment of changes in patient's level of sedation
assessment of patient's level of sedation using Ramsey sedation score; where 1=patient is anxious and agitated or restless, or both. 2= Patient is co-operative, oriented, and tranquil. 3= Patient responds to commands only. 4= Patient exhibits brisk response to light glabellar tap or loud auditory stimulus. 5= Patient exhibits a sluggish response to light glabellar tap or loud auditory stimulus. 6= Patient exhibits no response.
Time frame: Sedation scores will be recorded just before the initiation and 2 hours postoperatively
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Surgery will be started under spinal anesthesia. When sensory block regress to T12 dermatome Epidural bolus dose will be given epidural bolus dose of 12ml (10ml 0.25% bupivacaine + 10mg nalbuphine in 2ml volume) The onset of sensory blockade injected epiduraly with maximal cephalic spread will be assessed by bilateral pinprick method along the midclavicular line, every 5 min for 30 min and then every 30 min. top up dose of 8ml will be given postoperative (6ml 0.25% bupivacaine + 2mg nalbuphine in 2ml volume).