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Advanced Principles- Fall 2018 > Regional- upper body > Flashcards

Flashcards in Regional- upper body Deck (32)
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How is a nerve stimulator used for blocks?

  • The needle is insulated but current flows from the tip.
    • The current provides enough stimulation to reach "threshold" and stimulate the nerve
  • User can control settings (mA, mS, Hz)
    • usual settings: 1 mA, 0.1 mS, 2 Hz
  • After the nerve area is localized, decrease amps to 0.5 mA
    • if you have nerve response at <0.3 mA, your needle might be in the nerve
    • Goal: nerve response btw 0.3 mA and 0.5 mA


What equipment do you need to set up for a nerve block?

  • marker and ruler
  • chloroprep
  • lidocaine with small gauge needle
  • LA of choice in 20 ml syringes
  • 21 or 22 g B bevel needle of appropriate size for block
    • bevel is slightly more blunt than typical needle
  • nerve stimulator with EKG pad
  • gloves
  • anxiolytics


What are the common local anesthetics?

their concentrations?

How long do they act?

  • Very long acting
    • Liposomal bupivacaine (exparel)
  • Long acting
    • Ropivacaine (most common b/c it is less cardiotoxic than Bupivacaine
      • 0.5%
    • Bupivacaine
      • 0.25% to 0.75%
  • Short acting
    • Mepivacaine
      • 1.5%
    • Lidocaine
      • 1-2%


What are the max doses of the local anesthetics?

  • Bring Coke To Raves
    • Bupivacaine: 2.5 mg/kg
    • Cocaine: 3 mg/kg
    • Tetracaine: 3 mg/kg
    • Ropivicaine: 3 mg/kg
  • 4th house on ELM st has cars
    • Etidocaine: 4 mg/kg
    • Lidocaine: 4 mg/kg, 7 mg/kg with epi
    • Mepivacaine: 4 mg/kg, 7 mg/kg with epi
    • Chloroprocaine: 12 mg/kg


What medications may be added to locals as an adjunct?

  • Epi- (1:200,000 or 1:400,000)
    • can extend duration of action by causing vasoconstriction
    • often used as a vacular marker
  • Clonidine (alpha 2 agonist)- 75-100 mcg per 30 ml LA
    • will prolong DOA by hours
  • Buprenorphine (mixed opioid agonist-antag)
    • will prolong DOA
  • Dexamethasone- up to 4 mg to 30 ml LA
    • increase up to 10 hours
    • seen to be effective administered IV as well.



What are the different probes used for?


  • Linear probe (high frequency) gives great resolution for shallow tissue; often used for upper extremity blocks
    • 7-12 Hz
    • ideal for vascular and nerve structures
    • depts 6-8 cm
  • High frequency linear probe
    • 10-15 Hz
    • ideal for superficial nerve and vascular structures
  • Curved probe (low frequency) gives lower resolution but better penetration for deep structures
    • 4-7 Hz


What are the control settings and what do they do?

define hypOechoic, hypERechoic, in plane, and out of plane

  • gain- brightness of display

  • depth- how much depth is displayed on screen

  • frequency- higher frequency = greater resolution but less depth

  • hypoechoic- black

  • hyperechoic-white

  • in plane- inserting the needle lengthwise under the probe so you can see the entire needle on screen.

  • out of plane- inserting needle perpendicular to probe so you can only see pinpoint of needle.


What is the Raj test?

How is it performed?

What response should you see?

  • Used to determine how close needle is to nerve and make sure it is not intraneural
  • How is it done?
    • after minimal twitch elicited (0.2-0.5 mA)
    • 1 ml of LA injected
    • look for loss of motor stimulation
    • if twitch is still elicited at 0.1-0.2 mA needle should be withdrawn


Basic LA injection technique:

  • after nerve is found with US or PNS, gently aspirate for blood, CSF, or air
  • gently inject 1 ml of LA- should terminate twitch (Raj test)
  • aspirate again then inject 5 ml
    • should inject easily
    • observe for change in HR if using epi
  • repeat aspiration every 5 ml
  • observe for signs of toxicity


Do you remember the brachial plexus??

Good luck!

Randy Travis Drinks Beer


The four main upper extremity blocks work on which parts of the brachial plexus?


  • Interscalene block- roots and trunks
    • all terminal nerves except ulnar nerve
  • supraclavicular blocks- trunks and division
  • Infraclavicular- cords
  • axillary block- terminal branches
    • median, radial, and ulnar
  • ***the 5 terminal branches:
    • Musculocutaneous
    • axillary
    • median
    • radial 
    • ulnar


Musculocutaneous nerve:






  • Roots: C5,6, &7
  • innervates:
    • coracobrachialis
    • biceps
    • brachialis
  • motor: flex arm
  • sensory: lateral from elbow to wrist
  • **Not affected by axillary nerve block


Axillary Nerve:




  • Roots: C5,6
  • Motor:
    • deltoid- abducts elbow from body
    • teres minor
  • Sensory
    • inferior shoulder
    • upper lateral of arm


Radial Nerve:




  • Roots: C6, 7, 8, T1
  • Motor:
    • triceps
    • supinator and extensors of the forearm
  • Sensory:
    • posterior upper arm and forearm
    • lateral border of elbow
    • thumb and dorsal surface of hand 


Median Nerve:




  • Roots: C7, 8, & T1
  • Motor:
    • flexors and pronator muscles of forearm and wrist flexion
  • Sensory:
    • palmar surface of hand, index, and middle fingers
    • tips of index and middle fingers


Ulnar Nerve:




  • Roots: C8, T1
  • Motor
    • Flexor carpi ulnaris- finger abduction
  • Sensory
    • little finger and ring finger


Interscalene block:

For what type of surger?

Provides anesthesia to:

Does NOT provide anesthesia to:

  • Ideal for surgery of shoulder and upper arm
  • Provides anesthesia to C5, 6, 7
  • Does NOT provide anesthesia to ulnar nerve
    • do not use this block for procedures below the elbow.


Interscalene block:


  • Absolute:
    • contralateral recurrent laryngeal nerve palsy
    • phrenic nerve palsy
    • **you could accidentally block these nerves on the side you are doing the block and then they would be impaired on both sides.
  • Relative:
    • brachial plexus pathology
    • impaired pulmonary function
      • can the patient tolerate hemi-diaphragm paralysis?


Interscalene block:


  • Hornor's Syndrome (most common)- when LA spreads to cervical plexus (C3-C$) and sympathetic chain
    • Horny PAM
      • Ptosis
      • anhydrosis
      • miosis
  • Phrenic nerve block (common)
  • recurrent laryngeal nerve block (rare-hoarseness)
  • IV injection
  • subarachnoid/epidural injection
  • pneumothorax



What does it block?

What section of brachial plexus?

  • effectively blocks all portions of the upper extremity- hand, forearm, and upper arm
  • occurs in the trunk/division section of the brachial plexus
    • better at blocking inferior trunk than interscalene block


Supraclavicular contraindications

  • brachial plexus pathology
  • pneumothorax
  • coagulopathy- b/c sublcavian artery is non-compressible if punctured


Supraclavicular block complications:

  • Pneumothorax most associated with supraclavicular block than other blocks
    • apex of lung is medial and posterior to brachial plexus
    • sudden cough and SOB
  • vascular puncture
  • phrenic nerve block
  • horner's syndroms (less so than interscalene)


What is the infraclavicular block used for?

  • Infraclavicular block blocks all terminal branches
    • good for procedures distal to elbow
  • Onset takes longer due to nerves not being as compact
  • reduced risk of pneumothoraz


Infraclavicular block complications

  • vascular puncture
    • axillary vein and artery
    • non-compressible region
  • Risk of pneumothorax is low because block is outside of pleura


Axillary nerve block:

What is it used for?

What nerves does it block?

  • ideal for hand or forearm surgery (distal to elbow)
  • blocks ulnar, radial, and median nerves
    • musculocutaneous nerve requires a separate nerve block
  • Pt must be able to abduct and rotate arm 90 degrees



What are the different methods for performing an axillary block?

  • nerve stimulator
  • trans-arterial
  • ultrasound


What are the complications with axillary blocks?

  • vascular punchture
    • not a big issue--compress for 5 minutes
  • hematoma
  • IV injection
  • **if you accidentally puncture the artery, convert to transarterial technique


Intercostobrachial block:



  • Originates in the upper thorax- T2
  • Cutaneous innervation of the medial aspect of the upper arm
    • gets the sensory spot where the turnequit goes
    • NOT anesthetized with the brachial plexus
  • Field block- 5 ml


Bier block:



  • Advantages
    • ideal for hand or forearm cases that are under 60 minutes
    • performed without access to nerve stim or U/S
  • Disadvantages
    • often fails in obese arms
    • limited block duration
    • tourniquet pain
    • LA toxicity risk


How can you evaluate the block?

  • push (arm extension- radial nerve)
  • Pull (arm flexion- musculotaneous nerve)
  • Pinch (index finger- median nerve)
  • Pinch (little finger- ulnar nerve)