Regional- upper body Flashcards
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%
- Ropivacaine (most common b/c it is less cardiotoxic than Bupivacaine
- Short acting
- Mepivacaine
- 1.5%
- Lidocaine
- 1-2%
- Mepivacaine
What are the max doses of the local anesthetics?
-
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- Bupivacaine: 2.5 mg/kg
- Cocaine: 3 mg/kg
- Tetracaine: 3 mg/kg
- Ropivicaine: 3 mg/kg
-
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- 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.
Ultrasound:
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!
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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:
innervates:
motor:
sensory:
- 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:
Motor:
Sensory:
- Roots: C5,6
- Motor:
- deltoid- abducts elbow from body
- teres minor
- Sensory
- inferior shoulder
- upper lateral of arm
Radial Nerve:
Roots:
Motor:
Sensory:
- 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:
Motor:
Sensory:
- 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:
Motor:
Sensory:
- 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:
contraindications
- 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:
complications
- Hornor’s Syndrome (most common)- when LA spreads to cervical plexus (C3-C$) and sympathetic chain
- Horny PAM
- Ptosis
- anhydrosis
- miosis
- Horny PAM
- Phrenic nerve block (common)
- recurrent laryngeal nerve block (rare-hoarseness)
- IV injection
- subarachnoid/epidural injection
- pneumothorax
Supraclavicular:
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?
innervates?
- 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
disadvantages
- 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)
What are some additional upper extremity blocks?
- Single nerve “touch ups”
- ulnar, median, radial
- wrist block
- Superficial cervical plexus block
- unilateral procedures of the nec
- carotid endarterectomy
- Suprascapular nerve block
- posterior shoulder pain
- Continuous nerve catheter placements
Summary chart: Interscalene, supraclavicular, infraclavicular, axiallary, bier
List the brachial plexus part
volume
indications
and notes
