Epidural Nalbuphine Versus Dexmedetomidine as Adjuvants to Bupivacaine in Lower Limb Surgeries
Condition: Lower Limb Surgeries
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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].
    

Intervention name(s): normal saline; Dexmedetomidine; Nalbuphine
Intervention type(s): Drug; Drug; Drug
Intervention description(s): 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).; 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).
Intervention MeSH terms: Dexmedetomidine; Nalbuphine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The patients will be divided randomly by a computer-generated randomization table into three equal groups
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Epidural Nalbuphine; Epidural Dexmedetomidine; combined spinal-epidural anesthesia; lower limb surgeries