Indications
Primary anesthetic Postop pain management History PONV Malignant hyperthermia risk Patient severity unable to tolerate general anesthesia Surgeon preference
Absolute Contraindications
Patient refusal Severe aortic stenosis Active bleeding in anticoagulated patient Local anesthetic allergy Infection at proposed block site
Relative Contraindications
Respiratory compromise Inability to cooperate/understand the procedure Anesthetized patient Bloodstream infection Pre-existing peripheral neuropathy
Ultrasound advantages over traditional landmark technique
- Visualization anatomic structures
- Real-time needle movements
- Local anesthetic spread
SAFER
Nerve stimulation?
- Not always necessary in experienced providers
Long thoracic nerve stimulation helpful to AVOID
How much volume?
20-40mL per block
US guided vs. landmark technique
Complete block success demonstrated w/ 5mL
20mL relatively safe vs. 40mL local anesthetic (LAST risk)
Only inject 5mL after negative aspiration
Pre-Procedure
Verify correct patient Obtain informed consent Ensure patient understands procedure & risks Correct procedure & extremity Gather all necessary equipment Sedation pre-medication Place oxygen on patient w/ ETCO2 Obtain baseline vital signs & monitor during procedure Administer proper/adequate sedation
Cervical Plexus Block
Indications
Carotid endarterectomy
Superficial neck surgery
Clavicle fractures
Cervical Plexus
Branches & Nerves
Cervical nerve root C2-C4 Major nerves include - Transverse cervical - Great auricular - Lessor occipital - Supraclavicular
Cervical Plexus Block
Provides anesthesia to anterolateral neck, anterior & retro-auricular areas, & anterior chest inferior to the clavicle
Cervical Plexus Technique
- Position patient w/ head turned to non-operative side
- Place transducer at sternocleidomastoid muscle midpoint & move laterally until posterior edge identified
- Identify brachial plexus b/w anterior & middle scalene muscle
- Cervical plexus located in plane above prevertebral fascia
- Needle passed lateral to medial in-plane to area b/w sternocleidomastoid muscle & prevertebral fascia
Cervical Plexus Pearls
Visualization plexus nerves not necessary
Purely sensory nerves
Low local anesthetic concentration used
Cervical Plexus Complications
Poor needle visualization → intrathecal injection d/t close proximity to vertebral nerve roots
Potential intravascular injection in vertebral artery
Brachial Plexus
Ventral rami C5-T1 nerve roots
Converge & diverse into trunks, divisions, cords, branches, & terminal nerves
Supplies sensory & motor innervation to the upper extremity
Roots
5
C5 → T1
Trunks
3
Superior/upper
Middle
Inferior/lower
Divisions
6
Anterior (3)
Posterior (3)
Cords
3
Lateral
Posterior
Medial
Branches
5 Musculocutaneous Axillary Median Radial Ulnar
Proximal Branches
Dorsal scapular
Phrenic
Long thoracic
Medial Branches
Medial pectoral
Medial cutaneous to arm & forearm
Lateral Branches
Suprascapular
Subclavius
Lateral pectoral
Posterior Cord
Upper & lower subscapular
Thoracodorsal
EXTENSION
C5
Should abduction
C6
Elbow flexion
C7
Elbow extension
C8
Finger flexion
T1
Finger abduction/adduction
Block Evaluation
Baseline push, pull, pinch (medial), pinch (lateral)
Brachial Plexus Blocks
Supraclavicular SCB
Interscalene ISB
Infraclavicular
Axillary
Supraclavicular
TRUNK & DIVISION LEVEL
Reliable upper extremity block
Procedures involving upper arm & hand
Brachial plexus most compact at this level
SCB Technique
- Transverse image using in-plane needle insertion
- Trunks/divisions found lateral to pulsating subclavian artery & superior to 1st rib
- Needle inserted lateral to medial toward inferior plexus aspect where the rib & artery meet (the corner pocket)
SCB Complications
↑risk phrenic nerve paralysis & stellate ganglion block
Pneumothorax most important complication
Possible inadvertent subclavian artery puncture
Interscalene Block
ROOT LEVEL
Primary brachial plexus block for procedures involving the shoulder & proximal upper arm (suprascapular nerve)
Nerve roots C5-C7 found in interscalene groove b/w anterior & middle scalene muscles
Stoplight or snowman
ISB Technique
- Supine position w/ head turned to non-operative side
- Place transducer in mid-clavicular fossa & move cephalad
- Inject up to 20-30mL
Lateral → medial OR posterior → anterior
5cm
B level needle
ISB Pearls
Nerve stimulation not required
Pre-procedure scan w/ color doppler performed prior to injection to limit inadvertent injections & identify anatomic variations
ISB Complications
Phrenic blockade occurs nearly 100% time Stellate ganglion block LAST High spinal Injury to dorsal scapular & long thoracic nerves
Stellate Ganglion Block
Horner’s syndrome
- Ptosis
- Miosis
- Anhidrosis
Infraclavicular Block
CORD LEVEL
Alternative to supraclavicular block especially in patients w/ severe COPD or respiratory insufficiency
Cords labeled by relation to the axillary artery - lateral, posterior, & medial
Infraclavicular Technique
- Patient supine w/ head turned to non-operative side
- Abduct arm → shallow image
- Transducer placed perpendicular to clavicle medial to coracoid plexus
- Short-axis image (sagittal plane)
- Cords are arranged around the axillary artery
22G 8cm needle
Insert in-place cephalad → caudal
20-30mL incremental local anesthetic injection
Infraclavicular Pearls
Low frequency transducer depending on patient body habitus
Additional subcutaneous injection local anesthetic
Needle sliding medially ↑pneumothorax/hemothorax risk
Thoraco-acromial artery & pectoral veins pass b/w the pectoral muscles
Doppler useful to help identify structures & prevent inadvertent puncture
Infraclavicular Complications
Poor needle visualization → inadvertent - Pneumothorax/hemothorax - Vascular puncture - LAST event Uncomfortable pressure d/t separating tissue vs. nerve pain
Axillary Block
TERMINAL BRANCHES LEVEL - Musculocutaneous - Radial - Ulnar - Median Procedures below the elbow Less attractive block b/c other blocks able to be done w/ ultrasound efficiently w/ minimal complications
Axillary Technique
- Supine position w/ head turned to non-operative side
- Arm abducted & rotated externally
- Place transducer in the crease formed by biceps muscle & pectoris major
22G 5cm
B level needle
Insert in-plane
20-40mL incremental local anesthetic injection
Axillary Pearls
Compressing the veins ↓risk vascular puncture
Block the radial nerve 1st (deep)
Pre-procedure scan
Slide transducer distally to appreciate each nerve then follow proximally
Axillary Complications
Not common
↑risk vascular puncture b/c needle re-directed several times to achieve adequate local anesthetic distribution
Paresthesia d/t multiple needle punctures may result in neuropathy
CAUTION multiple veins located around the artery
Elbow Nerve Blocks
Incomplete block rescue
Localized procedure
- Radial
- Median & ulnar (blocked w/ arm abducted)
Find the contrast
All 3 nerves are close to vascular structures or bone
Median Nerve
Median nerve alongside brachial artery in upper arm to the elbow
Insert needle lateral → medial in-plane
Inject 4-5mL local anesthetic
Additional 2-3mL inject when circumferential spread not noted
Radial Nerve
Scan distally along the lateral humerus
Identify the nerve - anterior course along the humerus
Lateral → medial in-plane needle insertion
Inject 4-5mL local anesthetic
Additional 2-3mL inject when circumferential spread not noted
Ulnar Nerve
Scan medially to identify the medial epicondyle
Identify where nerve enters proximal & distal
Medial → lateral in-plane needle insertion
Inject 4-5mL local anesthetic
Additional 2-3mL inject when circumferential spread not noted
IV Regional Anesthesia
Bier block
Upper or lower extremity procedures
Local anesthetic injected into the venous system
Extremity exsanguinated via compression & isolated by tourniquet
IVRA Mechanisms
Direct - local bathing nerve endings in tissue
Indirect - local anesthetic transported to the nerves substance via the vasa nervorum
IVRA Indications
Superficial procedures - Ganglion cyst excision - Carpal tunnel release - Dupuytren's contractures - Fraction reduction (pediatrics) Regional pain syndromes treatment - Analgesia - Reduce neurogenic inflammation
IVRA Contraindications
Patient refusal Injuries to the injury (crush or open fractures) Inability to cannulate peripheral vein Local skin infection or cellulitis True allergy to local anesthetics Pre-existing AV fistula Sickle cell disease Surgery >1hr
IVRA Procedure
Place IV catheter 22G distal
Apply double pneumatic tourniquet
Elevate the extremity & apply esmarch bandage
Occlude the axillary
Inflate proximal cuff 50-100mmHg > patient systolic
Remove esmarch
Inject 30-50mL 0.5-1% lidocaine
Tourniquet pain → inflate distal cuff then deflate proximal cuff
IVRA Pearls
Tourniquet must remain inflated at least 30 minutes following local anesthetic injection regardless surgery length
Cuff tourniquet deflation cyclical
- Deflate then instantly re-inflate
- Evaluate S/S LAST or other complications
- Wait 1-2 minutes
- Repeat
IVRA Complications
LAST Damage to radial, median, & ulnar nerves Compartment syndrome Arterial thrombosis Death or permanent brain damage
LAST
Local anesthetic systemic toxicity
Serious, but rare event during regional anesthesia
Occurs from inadvertent IV injection
- Blocking inhibitory neurons causes seizures
- Cardiac ion channel blockage → bradycardia
Short-acting local anesthetics less cardiotoxic
More potent agents ↑lipid solubility & protein binding
LAST Clinical Presentation
Rapid onset usually w/in 1 minute
Agitation, tinnitus, circumoral numbness, blurred vision, & metallic taste
Followed by muscle twitching, unconsciousness, & seizures → cardiac & respiratory arrest
LAST Incidence
0.4 per 10,000
LAST most commonly associated w/
Epidural
Axillary
Interscalene
LAST Prevention
Test dosing
Incremental injection 5mL w/ aspiration
Use pharmacologic markers
Ultrasound
LAST Treatment
Prompt recognition & diagnosis Airway management Suppress seizure - Benzodiazepines - Succinylcholine Prevent hypoxia & acidosis Lipid emulsion therapy Vasopressors - Epi <1mg/kg
Nerve Injury
Direct needle trauma - peripheral nerve injury varies w/ location
Local anesthetic neurotoxicity
US allows practitioner to identify important structures - dura, pleural, vasculature, bowel
Visualize needle in real-time & observe LA spread
Nerve Injury
↑Risk
Diabetes - diabetic neuropathy ↓sensation baseline Pre-existing neurologic disease Smoking ↑BMI Male
Lipid Emulsion Therapy MOA
Capture LA in blood (lipid sink) ↑fatty acid uptake by mitochondria Na+ channel binding interference Ca2+ entry promotion Accelerated shunting