Dexmedetomidine in Serratus Plane Block for Mastectomy
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional

Summary: 
      The serratus plane block (SPB) described by Blanco et al, 2013 is a progression from the work
      with the Pecs I and II blocks. The serratus muscle is a superficial and easily identified
      muscle and considered a true landmark to perform thoracic wall blocks because lateral
      cutaneous branches of the intercostal nerves pierce it in the mid-axillary line. A local
      anesthetic (LA) is injected under ultrasound (US) guidance either superficial or deep to
      serratus anterior muscle providing predictable and relatively long-lasting regional
      anesthesia, which would be suitable for surgical procedures performed on the chest wall.

      The linear US probe of frequency (6-13 MHz) is placed over the mid-clavicular region in a
      sagittal plane.The ribs are counted inferiorly and laterally until the fifth rib in the
      midaxillary line is identified.The latissimus dorsi, teres major, and serratus muscles are
      identified.
    

Detailed description: 
      Possible regional techniques for breast surgery include selective intercostal nerve blockade,
      thoracic paravertebral blockade, thoracic epidural, intrapleural, local wound infiltration.
      Each of these techniques has advantages and disadvantages. In general, local or wound
      infiltration is safe but limited in terms of duration of action, depending on the local
      anesthetic (LA) used. More invasive techniques such as selective intercostal nerve blocks and
      thoracic paravertebral blockade may be complicated by pneumothorax or transient Horner's
      syndrome These techniques are also may be associated with higher risk of local anesthetic
      toxicity. Besides the neurological side-effects associated with thoracic epidural and
      paravertebral blocks such as post-sympathectomy hypotension and bradycardia, total spinal
      block, paraplegia, epidural hematoma, unpredictable spread, intravascular injection also
      requires special skill precluding their routine use in the setting of day-case surgery. With
      the use of ultrasound (US) devices in anesthetic practice, newer regional techniques based on
      detailed knowledge of innervations of the breast are developed as the pectoral nerve (Pecs)
      block I and II.The breast innervations briefly include lateral and medial pectoral nerves
      that arise from the brachial plexus innervating the pectoral muscles.The anterior divisions
      of the thoracic intercostal nerves from T2 to T6. They give off lateral and anterior
      branches. The Lateral branches pierce the external intercostalis and the serratus anterior
      muscles at the mid-axillary line to give off anterior and posterior terminal cutaneous
      branches. The lateral cutaneous branch of the second intercostal nerve does not divide and it
      is called the intercostobrachial nerve.The Anterior branches pierce the internal
      intercostalis muscle, the intercostal membranes, and pectoralis major to supply the breast in
      its medial aspect.The long thoracic nerve passes on the serratus anterior muscle supplying
      it. The thoracodorsal nerve innervates the latissimus dorsi muscle.
    

Intervention name(s): Bupivacaine-Dexmedetomidine; Bupivacaine; General anesthesia
Intervention type(s): Drug; Drug; Drug
Intervention description(s): isobaric bupivacaine 2.5 mg/ml plus 5 micro gram/ml adrenaline and 1 micro gram/kg dexmedetomidine in a volume of 0.5 ml/kg; isobaric bupivacaine 2.5 mg/ml plus 5 micro gram/ml adrenaline in a volume of 0.5 ml/kg; Normal saline in a volume of 0.5 ml/kg
Intervention MeSH terms: Dexmedetomidine; Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Supportive Care