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Regional Anesthesia in the Outpatient Setting

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Regional Anesthesia in the Outpatient Setting Powered By Docstoc
					Regional Anesthesia in
the Outpatient Setting



         Ravindra V. Prasad, MD
       Department of Anesthesiology
         UNC School of Medicine
              Review
   3/30 – Ghia, Axillary Block
   4/1 – Wilkes, Axillary Block
   4/8 – Levin, SAB
   4/14 – Klein, Lower Extremity Blocks
   4/15 – Prasad, ???
              Overview
   Regional Anesthesia: general comments
   Upper Extremity Blocks
   Paravertebral Blocks
   Neuraxial Blocks
   Lower Extremity Blocks
               Regional: advantages
 Avoid GA complications
 Less anesthetic required
     faster wake-up?
     quicker recovery?
 Faster ambulation, faster discharge
     N/V less common
     post-op pain minimized
                Regional: problems
   Time
   Equipment
   Personnel
   GA still backup plan
   Skill
       regional techniques
       management of awake or LIGHTLY sedated
        patients
           Block Placement
 Monitoring
 Emergency equipment and drugs should be
  readily available
 Block equipment readied before starting
 POSITIONING
 SEDATION (preoperative, intraoperative)
 Patient selection
Upper Extremity Blocks
 Brachial Plexus Blocks
 Peripheral Nerve Blocks
     elbow
     wrist
 Bier Blocks
Brachial Plexus
Dermatome Distribution
Brachial Plexus Blocks
 Indications: surgery of upper extremity
 Approaches
     Axillary
     Infraclavicular
     Supraclavicular
     Interscalene (ISB)
ISB: technique
 Equipment
 Drugs
 Technique
ISB: complications
   Pneumothorax
   Phrenic nerve paralysis
   Horner’s syndrome
   C6 root neuropathy (intraneural injection;
    root pinned against C6 tubercle)
Bier Block
 Intravenous Regional Anesthesia (IVRA)
 Described by Bier in 1908
 Intravenous injection of local anesthetics in
  an extremity isolated from the systemic
  circulation
 A simple technique which is easy to
  perform
 Widespread use in surgical cases of short
  duration
Bier Block: indications
 Surgery of the extremities, especially hand
  and forearm
 Surgery of short duration (less than 1 hour)
 Soft tissue procedures (block is less dense
  than nerve blocks; may have pain if bony
  involvement)
Bier Block: contraindications
 Disease processes or states
     prolonged tourniquet times contraindicated
      (Sickle Cell Disease or Trait)
     more susceptible to toxic effects of agents used
      (Heart Block)
 Hypersensitivity/allergy to agents used
 Patients with a painful extremity
 Certain patient body habitus
Bier Block: technique
 Equipment
     tourniquet(s) with pressure gauge
     rubber bandage (Martin, Esmarch)
 Drugs
     Local Anesthetics: Lidocaine 0.5% or
      Prilocaine 0.5%
     Opioids
     Ketorolac
Bier Block: mechanisms of
action
 Direct action at nerve endings
 Diffusion into nerve trunks
     Nerve trunks consist of fascicles covered with
      epineurium
     Blood vessels contained within the epineurium
     Capillaries within endoneurium extend
      intraneurally as vasa nervorum
     Local anesthetic diffusion occurs from nerve
      core to the periphery
Bier Block: complications
 Local anesthetic systemic toxicity
     Premature tourniquet release, malfunctioning
      tourniquet
     Leakage through intraosseous veins or ordinary
      veins
 Direct tissue local anesthetic toxicity
  (neuronal, muscular, vascular injury )
 Ischemic injury (prolonged tourniquet time,
  excessive tourniquet pressure)
Bier Block: pearls
   Tourniquet pain
   Tourniquet deflation
   Prolonged surgery
   Lower extremity surgery
Paravertebral Blocks (PVB)
 Paravertebral space
 Spinal root emerges
  from intervertebral
  foramen, divides into
  dorsal and ventral
  rami and sympathetics
 Unilateral motor,
  sensory, and
  sympathetic block
PVB Indications
 Thoracic
     thoracotomy
     mastectomy
     nephrectomy
     cholecystectomy
     rib fractures
     post-thoracotomy pain
     post-mastectomy pain
 Lumbar: inguinal hernia
PVB: technique
 Equipment
 Drugs
 Technique
      2.5-3 cm lateral to
       spinous process, caudal
       and 1-2 cm deep to
       transverse process
      4-5 ml local anesthetic
 Variations
PVB: risks
 Complication                   Adults   Children   Greengrass
                                (319)    (48)       (156)
 Pleural puncture               3        1
 Pneumothorax, symptomatic      1        0          1
 Bloodstained aspirate          12       2
 Hypotension (requiring fluid   16       0
 or ephedrine)
 Epidural involvement                               2
 Epinephrine absorption                             1


     Reported failure rate 10-15%
PVB: breast surgery
 Block T1-T6: go lateral to C7-T5.
 Greengrass:
     Retrospective review, 156 blocks in 145
      patients vs. 100 GA over 2-year period
     85% block alone
     91% block + local
     2.6% complication (4/156)
PVB vs. GA: breast surgery

  Complication                  PVB %   GA %
  Require N/V med during        20      39
  hospital stay
  Narcotic analgesia required   25      98
  during hospital stay
  Discharged POD #0             96      76
PVB: inguinal hernia repair
 Block T10-L2: go lateral to T10-L2
 Onset of surgical anesthesia 15-30 min
PVB: IH Repair, outcome
 22 patients. 3 converted to GA
     1/3 had good block at emergence
     failure rate 2-3/22 = 9-14%
 Of 20 “successful” blocks
     Onset of discomfort 14  11 hrs, first narcotic 22  18
      hrs
     13 (65%) no incisional discomfort for at least 10 hrs
      after block
     3 (15%) epidural spread
                                    Klein, SM Greengrass RA Weltz C Warner DS, 1998
PVB: inguinal hernia, satisfaction

    Satisfaction with anesthetic   24 hr   48 hr
    Not satisfied                  0       0
    Satisfied                      3       2
    Very satisfied                 17      18
            SAB
 Duration
 Disadvantages
 Advantages vs. epidural
Duration, SAB

                             Duration of Sensory Block, SAB
 Drug          Dose   2-Dermatome        Complete         Prolongation by
               (mg)   regression (min) Resolution (min) -Agonists (%)
 Procaine      50-200 30-50              90-120           30-50
 Lidocaine     25-100 40-100             140-240          20-50
 Bupivacaine   5-20   90-140             240-380          20-50
 Tetracaine    5-20   90-140             240-380          50-100
Epidural
 Duration
 Disadvantages
 Advantages vs. SAB
Duration, Epidural

                                  Duration of Sensory Block, Epidural
Drug                    2-Dermatome        Complete           Prolongation by
                        regression (min) Resolution (min) -Agonists (%)
Chloroprocaine 3%       45-60              100-160            40-60
Lidocaine 2%            60-100             160-200            40-80
Mepivacaine 2%          60-100             160-200            40-80
Ropivacaine 0.5-1.0%    90-180             240-420            No
Etidocaine 1-1.5%       120-240            300-460            No
Bupivacaine 0.5-0.75%   120-240            300-460            No
Summary
 Regional anesthesia is good
 Use it!

				
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