Nerve Blocks in the Emergency Department

Quick Reference

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Quick Answer

Nerve blocks provide targeted analgesia for ED procedures by depositing local anesthetic near peripheral nerves. Ultrasound guidance increases success rates (85-98% vs 60-75% landmark technique) and reduces complications. Common ED blocks include femoral nerve block (hip/femur fractures), fascia iliaca compartment block (FICB), interscalene brachial plexus block (shoulder), digital blocks (finger injuries), and dental blocks (tooth pain). Local anesthetic systemic toxicity (LAST) is the most serious complication - treat with lipid emulsion 20% (1.5 mL/kg bolus). Maximum doses: bupivacaine 2 mg/kg (3 mg/kg with adrenaline), lidocaine 4.5 mg/kg (7 mg/kg with adrenaline).

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ACEM Exam Focus

Fellowship Written Exam

• Anatomy: Peripheral nerve course, relations to vessels, fascial planes
• Pharmacology: Local anesthetic maximum doses, duration of action, systemic toxicity
• Ultrasound: In-plane vs out-of-plane needle technique, nerve identification
• LAST management: Recognition, lipid emulsion dosing, ECMO indications

Fellowship OSCE

• Procedural station: Perform ultrasound-guided femoral or digital block on model
• Communication: Consent for nerve block, explain risks/benefits
• Complication management: Recognize and manage LAST

Key Viva Topics

1. Indications and contraindications for common ED nerve blocks
2. Local anesthetic pharmacology and maximum safe doses
3. Ultrasound-guided vs landmark techniques
4. LAST recognition and management algorithm
5. Anatomical basis for specific nerve blocks

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Key Points

1. Ultrasound guidance increases success rates to 85-98% (vs 60-75% landmark) and reduces complications by 65% compared to landmark technique (PMID: 29775286, 21669577)

2. Maximum safe doses (without adrenaline): Bupivacaine 2 mg/kg, Ropivacaine 3 mg/kg, Lidocaine 4.5 mg/kg, Levobupivacaine 2.5 mg/kg (PMID: 28254067, 17921671)

3. LAST presentation: Early CNS signs (perioral numbness, tinnitus, agitation, seizures) followed by cardiovascular collapse (hypotension, arrhythmias, cardiac arrest) (PMID: 28254067, 20354420)

4. Lipid emulsion therapy: 20% Intralipid 1.5 mL/kg IV bolus over 1 minute, then 0.25 mL/kg/min infusion for LAST (PMID: 28254067, 20354420, 18784232)

5. Femoral nerve block provides superior analgesia vs IV opioids for femoral neck fractures (NRS reduction 3.5 vs 1.2 points, PMID: 24239333, 21911550)

6. Fascia iliaca compartment block (FICB) has lower complication rate than femoral nerve block (no vascular puncture risk) and similar efficacy (PMID: 21911550, 19608378)

7. Digital block with adrenaline is SAFE - systematic review of 3,110 cases showed zero digital necrosis (PMID: 25611100, 28414436)

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Indications

Absolute Indications

• Fracture reduction: Femur, hip, radius, shoulder dislocation
• Laceration repair: Complex hand, finger, foot lacerations
• Abscess drainage: Large abscesses requiring extensive incision
• Procedural sedation alternative: High-risk patients (elderly, cardiac/respiratory comorbidities)
• Multimodal analgesia: Rib fractures, long bone fractures

Relative Indications

• Opioid-sparing analgesia: Opioid-intolerant or opioid-seeking patients
• Prolonged ED wait: Analgesia while awaiting OR
• Pre-hospital analgesia: HEMS/retrieval medicine (femoral, FICB)

When to Consider

• Any fracture requiring manipulation or transportation analgesia
• Complex wound repair in sensitive areas (fingers, toes, face)
• Patients refusing or unsuitable for procedural sedation
• Rib fractures interfering with ventilation (serratus anterior plane block, erector spinae plane block)

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Contraindications

Absolute

Relative

• Compartment syndrome - nerve block may mask evolving compartment syndrome
• Pre-existing neuropathy in target nerve distribution
• Anticoagulation (warfarin, DOACs) - risk vs benefit for compressible sites
• Sepsis - theoretical bacteremia seeding risk
• Severe hypovolemia - vasodilation from local anesthetic may worsen hypotension

Risk-Benefit Considerations

• Compartment syndrome concerns: Use short-acting local anesthetic (lidocaine 1-2 hours), frequent neurovascular checks, low-dose blocks
• Anticoagulation: Femoral nerve block and FICB are relatively contraindicated (non-compressible); digital and forearm blocks acceptable
• Elderly with dementia: Difficult to assess block success or complications - consider alternative analgesia

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Anatomy

Common ED Nerve Blocks - Anatomical Summary

Femoral Nerve Anatomy

Origin: Lumbar plexus (L2-L4) Course: Descends through psoas, emerges under inguinal ligament lateral to femoral artery Nerve relations:

• Lateral: Iliopsoas muscle
• Medial: Femoral artery (remember NAVY - Nerve, Artery, Vein, Y-fronts medial to lateral)
• Anterior: Fascia lata and fascia iliaca
• Posterior: Iliopsoas muscle

Ultrasound appearance: Hyperechoic triangular structure lateral to femoral artery, depth 1-3 cm

Fascia Iliaca Compartment (FICB) Anatomy

Fascial plane: Between fascia iliaca (deep) and fascia lata (superficial) Target: Deposit local anesthetic below fascia iliaca to spread to femoral, lateral femoral cutaneous, and obturator nerves Landmark: 1 cm distal to inguinal ligament, junction of medial 1/3 and lateral 2/3 of line from ASIS to pubic tubercle

Advantages over femoral nerve block:

• Lower risk of vascular puncture (no vessel proximity)
• Covers lateral femoral cutaneous nerve (femoral block does not)
• Easier landmark technique (2-pop technique - fascia lata then fascia iliaca)

Brachial Plexus (Interscalene) Anatomy

Nerve roots: C5, C6, C7 (± C8, T1 contribution) Location: Between anterior and middle scalene muscles at C6 level (cricoid cartilage) Target: C5-C6 nerve roots appearing as "stoplight" sign on ultrasound (3 hypoechoic circles stacked)

Coverage:

• Shoulder joint (C5-C6)
• Lateral upper arm (C5-C6)
• Does NOT block ulnar nerve (C8-T1) or medial forearm

Digital Nerve Anatomy

Course: Common digital nerves bifurcate at metacarpal head level into proper digital nerves (2 per finger - radial and ulnar sides) Location: Volar-lateral aspect of digit, running with digital arteries

Approaches:

1. Dorsal web space (traditional): Inject at base of finger, web space
2. Transthecal (single injection): Through flexor tendon sheath at A1 pulley
3. Volar subcutaneous: Volar base of proximal phalanx

Epinephrine safety: Modern evidence supports epinephrine use in digital blocks (3,110 cases, zero necrosis - PMID: 25611100)

Inferior Alveolar Nerve (Dental Block) Anatomy

Origin: Branch of mandibular division of trigeminal nerve (V3) Course: Enters mandibular foramen on lingual surface of ramus Landmark: Pterygomandibular raphe (palpable band between pterygoid and masseter)

Injection site: 1 cm above occlusal plane of lower molars, just lateral to pterygomandibular raphe

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Equipment

Essential Equipment

Optional Equipment

Equipment Sizing

Adult

Paediatric

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Preparation

Patient Preparation

1. Informed consent: Explain procedure, risks (nerve injury below 0.1%, LAST below 0.01%, vascular puncture 1-5%), benefits, alternatives
2. Positioning:
   • Femoral/FICB: Supine, leg externally rotated, knee slightly flexed
   • Interscalene: Sitting or supine, head turned away from injection side
   • Digital: Hand supine, finger slightly flexed
3. Monitoring: Continuous pulse oximetry, ECG, BP monitoring (for LAST detection)
4. IV access: Mandatory for all nerve blocks (for LAST treatment)
5. Pre-procedure check: Verify correct limb/side, mark site, check LA dose calculation

Operator Preparation

1. Standard precautions: Mask, sterile gloves, gown (for large volume blocks)
2. Hand hygiene: Alcohol-based handrub
3. Equipment check:
   • Ultrasound functioning, image optimized
   • Needles, syringes, LA drawn up
   • Aspiration performed before injection
   • Lipid emulsion 20% immediately available
4. Assistance arranged: Nurse to monitor patient, assist with equipment
5. Backup plan identified: Procedural sedation, IV analgesia if block fails

Site Preparation

1. Sterile technique: Aseptic non-touch technique (ANTT) for all blocks
2. Skin preparation: Chlorhexidine 2% in 70% alcohol (allow to dry 30 seconds)
3. Draping: Sterile drape for interscalene/femoral blocks; clean technique acceptable for digital blocks
4. Probe preparation: Sterile gel inside probe cover, secure with elastic band

Positioning

Femoral/FICB:

• Patient position: Supine, leg in 15° external rotation, knee slightly flexed
• Operator position: Stand on ipsilateral side of bed
• Assistant position: Opposite side for monitoring

Interscalene:

• Patient position: Supine or semi-recumbent, head turned 30-45° away from block side
• Operator position: At head of bed, facing patient
• Assistant position: Side of bed for monitoring

Digital block:

• Patient position: Hand resting on bedside table, palm up
• Operator position: Sitting opposite patient
• Assistant: Not required for digital blocks

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Procedure Steps

Femoral Nerve Block (Ultrasound-Guided)

Step 1: Ultrasound Scanning

• Place linear probe in transverse orientation at inguinal crease
• Identify femoral artery (pulsatile anechoic circle)
• Identify femoral nerve lateral to artery (hyperechoic triangular or oval structure)
• Optimize depth (3-4 cm) and gain to visualize nerve clearly
• Key point: Nerve is lateral to artery; if unsure, use color Doppler to confirm artery location
• Common error: Confusing iliopsoas muscle edge for nerve - nerve is more superficial and hyperechoic

Step 2: Skin Infiltration

• Infiltrate skin lateral to probe with 1-2 mL of 1% lidocaine using 25G needle
• Key point: Skin wheal 1-2 cm lateral to probe edge (for in-plane approach)
• Common error: Inadequate skin anesthesia - patients may move during block needle insertion

Step 3: Needle Insertion (In-Plane Technique)

• Insert 22G 5-8 cm needle from lateral to medial, in-plane with probe
• Visualize needle shaft and tip advancing toward nerve
• Avoid passing through femoral artery
• Key point: Needle tip must be visible at all times - if lost, withdraw and redirect
• Common error: Out-of-plane needle trajectory - only see needle tip as bright dot (unsafe)

Step 4: Local Anesthetic Injection

• Position needle tip adjacent to femoral nerve (not intraneural)
• Aspirate before injection to exclude intravascular placement
• Inject 1-2 mL test dose, observe for "donut sign" (LA circumferential spread around nerve)
• If no spread, reposition needle tip
• Inject total 15-20 mL of 0.5% bupivacaine or 0.5% ropivacaine slowly (over 1-2 minutes)
• Key point: Avoid high injection pressure (greater than 20 psi) - suggests intraneural injection
• Common error: Intravascular injection - always aspirate every 5 mL

Step 5: Post-Procedure Assessment

• Assess sensory block in anterior thigh and medial leg (femoral nerve distribution)
• Assess motor block: Knee extension weakness (quadriceps)
• Onset: 10-20 minutes for full block
• Duration: 8-12 hours (bupivacaine/ropivacaine)

Confirmation of Success

• circumferential LA spread around nerve |

Fascia Iliaca Compartment Block (Landmark Technique)

Step 1: Landmark Identification

• Identify anterior superior iliac spine (ASIS) and pubic tubercle
• Draw line connecting ASIS to pubic tubercle
• Mark point at junction of medial 1/3 and lateral 2/3 of line
• Mark point 1-2 cm distal to inguinal ligament (to avoid peritoneum)

Step 2: Needle Insertion (2-Pop Technique)

• Insert 22G 5 cm needle perpendicular to skin at marked point
• Advance until first "pop" felt (fascia lata)
• Continue advancing until second "pop" felt (fascia iliaca) - usually 1-2 cm deeper
• Key point: Two distinct "pops" must be felt - if only one pop, not below fascia iliaca
• Common error: Stopping after first pop - LA deposited above fascia iliaca (block fails)

Step 3: Local Anesthetic Injection

• Aspirate to exclude vascular puncture
• Inject 30-40 mL of 0.25-0.5% bupivacaine or 0.5% ropivacaine
• High volume required for spread to femoral, lateral femoral cutaneous, and obturator nerves
• Apply digital pressure distal to injection site for 2 minutes (to encourage proximal LA spread)
• Key point: Large volume (30-40 mL) essential for FICB - inadequate volume = block failure
• Common error: Using below 30 mL volume - insufficient spread to cover all target nerves

Digital Nerve Block (Dorsal Web Space Approach)

Step 1: Positioning and Preparation

• Hand resting palm-up on table
• Prepare 3-5 mL of 1% lidocaine (±1:100,000 epinephrine) in 10 mL syringe
• Use 25-27 gauge needle (1.5 inch)

Step 2: Injection (Web Space)

• Insert needle at base of finger, dorsal web space
• Advance needle to volar side (but do not pierce volar skin)
• Aspirate, then inject 2-3 mL slowly as needle withdrawn
• Repeat on opposite side of finger
• Total volume: 4-6 mL for complete digital block
• Key point: Inject slowly while withdrawing - avoid needle trauma to digital nerve
• Common error: Using excessive volume (greater than 10 mL) - may cause vascular compromise

Step 3: Assessment

• Onset: 5-10 minutes
• Test sensation distal to injection site
• Expected: Complete sensory block of entire digit

Inferior Alveolar Nerve Block (Dental Block)

Step 1: Landmark Identification

• Palpate coronoid notch (depression anterior to temporomandibular joint)
• Palpate pterygomandibular raphe (taut vertical band between pterygoid and masseter)
• Injection site: 1 cm above occlusal plane of lower molars, just lateral to raphe

Step 2: Needle Insertion

• Use 27 gauge 1.5 inch needle
• Insert from contralateral premolar region, parallel to occlusal plane
• Advance 1.5-2 cm toward mandibular foramen
• Key point: Keep needle close to medial ramus - if too lateral, misses nerve
• Common error: Inserting needle too deep - may enter parotid gland (facial nerve palsy)

Step 3: Local Anesthetic Injection

• Aspirate carefully (inferior alveolar artery proximity)
• If negative aspiration, inject 1.5-2 mL of 2% lidocaine with 1:100,000 epinephrine
• Onset: 5-10 minutes
• Duration: 2-3 hours (with epinephrine)

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Ultrasound Guidance

When to Use

• All femoral nerve blocks: Ultrasound increases success rate from 75% to 95% (PMID: 29775286)
• Interscalene blocks: Reduces complications (vertebral artery injection, phrenic nerve palsy rate unchanged)
• Fascia iliaca blocks: Ultrasound superior to landmark for fascial plane identification
• Digital blocks: Not required - landmark technique highly effective

Probe Selection

Technique

Probe Orientation:

• Transverse (short axis): Nerve appears as circle or oval
• Longitudinal (long axis): Nerve appears as linear structure (rarely used in ED)

Needle Approach:

• In-plane: Needle shaft visible along its entire length - PREFERRED for safety
• Out-of-plane: Only needle tip visible as bright dot - higher risk of vascular puncture

Key Views:

• Femoral nerve: Hyperechoic triangle lateral to femoral artery, depth 1-3 cm
• Brachial plexus (interscalene): "Stoplight" sign - 3 hypoechoic circles (nerve roots) between scalene muscles
• Fascia iliaca: Hyperechoic line deep to iliopsoas muscle

Sonographic Anatomy

Femoral Nerve:

• Appearance: Hyperechoic triangular or oval structure
• Relations: Lateral to femoral artery (pulsatile), superficial to iliopsoas (hypoechoic muscle)
• Depth: 1-3 cm in adults

Brachial Plexus (Interscalene Level):

• Appearance: 3 hypoechoic circles ("traffic lights") stacked vertically
• Relations: Between anterior scalene (medial) and middle scalene (lateral) muscles
• Depth: 1-2 cm

Nerve vs Tendon Differentiation:

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Alternative Techniques

Landmark (Blind) Technique vs Ultrasound-Guided

When to use landmark:

• Ultrasound not available
• Digital nerve blocks (highly reliable anatomical landmarks)
• Fascia iliaca block (2-pop technique)

Advantages of landmark:

• Faster setup (no equipment preparation)
• Useful in austere environments (RFDS, remote)
• Lower cost

Disadvantages of landmark:

• Lower success rate (60-75% vs 85-98% ultrasound)
• Higher complication rate (vascular puncture 5-10% vs below 1% ultrasound)
• Cannot visualize vascular structures or LA spread

Nerve Stimulator-Guided Technique

Principle: Low-amperage electrical current (0.5-1.0 mA) stimulates motor nerve, producing muscle twitch when needle near nerve

When to use:

• Ultrasound not available
• Adjunct to ultrasound (confirmation of nerve proximity)

Advantages:

• Confirms nerve proximity (motor response at 0.3-0.5 mA indicates optimal position)
• Does not require ultrasound skills

Disadvantages:

• Does not visualize vascular structures (cannot prevent vascular puncture)
• Ineffective for sensory nerves (e.g., lateral femoral cutaneous)
• Prolonged procedure time
• Less reliable in elderly or neuropathic patients

Continuous Nerve Block Catheters

Indications:

• Prolonged analgesia required (greater than 12 hours) - e.g., rib fractures, multitrauma
• ICU patients with ongoing pain
• Patients awaiting delayed surgery

Technique:

• Insert catheter through introducer needle under ultrasound guidance
• Infuse local anesthetic at 5-10 mL/hour (0.2% ropivacaine)

Contraindications:

• Infection risk (prolonged catheter dwell time)
• Patients unable to report complications

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Additional ED Nerve Blocks

Serratus Anterior Plane (SAP) Block

Indications:

• Rib fractures (anterolateral chest wall T2-T9)
• Chest tube insertion analgesia
• Breast abscess drainage

Anatomy:

• Target: Plane between serratus anterior muscle (superficial) and intercostal muscles (deep)
• Level: 5th rib at mid-axillary line
• Nerves blocked: Lateral cutaneous branches of intercostal nerves T2-T9

Ultrasound Technique:

1. Patient position: Lateral decubitus, arm elevated
2. Probe position: Linear probe at mid-axillary line, ribs 4-6 level
3. Identify ribs (hyperechoic with acoustic shadow), latissimus dorsi (superficial), serratus anterior (intermediate), intercostal muscles (deep)
4. In-plane needle approach: Superficial to deep, aiming for plane between serratus and intercostal muscles
5. Inject 20-30 mL of 0.5% ropivacaine or 0.25% bupivacaine
6. Observe LA spread along fascial plane

Advantages over intercostal blocks:

• Single injection (vs multiple intercostal blocks)
• Lower pneumothorax risk (more superficial)
• Longer duration (blocks multiple dermatomes)

Evidence: PMID: 28540450 (SAP block for rib fractures)

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Erector Spinae Plane (ESP) Block

Indications:

• Rib fractures (posterior/lateral chest wall)
• Vertebral compression fractures
• Herpes zoster pain (acute)
• Flail chest

Anatomy:

• Target: Fascial plane deep to erector spinae muscle, superficial to transverse processes
• Level: T5 transverse process (for mid-thoracic coverage T2-T9)
• Mechanism: LA spreads cranio-caudally and penetrates paravertebral space via costotransverse foramina

Ultrasound Technique:

1. Patient position: Sitting or lateral decubitus
2. Probe position: Longitudinal (sagittal) 3 cm lateral to midline at T5 level
3. Identify "sawtooth" pattern of transverse processes (hyperechoic)
4. Identify erector spinae muscle (superficial to transverse process)
5. In-plane needle approach: Cranio-caudal direction, aiming for plane between erector spinae and T5 transverse process
6. Inject 20-30 mL of 0.5% ropivacaine
7. Observe "fluid lift-off" of erector spinae muscle from transverse process

Advantages:

• Versatile (thoracic, abdominal, pelvic pain)
• Low complication rate (no vascular/pleural proximity)
• Easy to learn (superficial plane, clear landmarks)

Evidence: PMID: 32252119 (ESP block in ED), PMID: 28188621 (ESP for analgesia)

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Forearm Nerve Blocks (Radial, Median, Ulnar)

Indications:

• Hand lacerations
• Metacarpal/phalangeal fractures
• Carpal tunnel release (median nerve block)
• Foreign body removal from hand

Anatomy:

Median Nerve Block (Wrist):

1. Landmark: Between palmaris longus and flexor carpi radialis tendons, 2 cm proximal to wrist crease
2. Needle: 25G, 1 inch
3. Insert perpendicular to skin, advance 1 cm
4. Aspirate, inject 3-5 mL of 1% lidocaine
5. Avoid intraneural injection (patient reports electric shock to thumb/fingers)

Ulnar Nerve Block (Wrist):

1. Landmark: Medial to flexor carpi ulnaris tendon, 2 cm proximal to wrist crease
2. Insert needle perpendicular, advance 0.5-1 cm (nerve is superficial)
3. Inject 3-5 mL of 1% lidocaine around nerve
4. Caution: Ulnar artery is lateral to nerve - aspirate to avoid intravascular injection

Radial Nerve Block (Wrist):

1. Landmark: Dorsal wrist over radial styloid
2. Subcutaneous infiltration (nerve has multiple superficial branches at wrist)
3. Create "bracelet" of LA from radial styloid to mid-dorsum of wrist
4. Inject 5-10 mL of 1% lidocaine subcutaneously
5. Onset: 10-15 minutes

Evidence: PMID: 26281816 (forearm nerve blocks)

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Hematoma Block (Distal Radius Fracture)

Indications:

• Closed reduction of distal radius fractures (Colles', Smith's)
• Alternative to Bier's block or procedural sedation

Contraindications:

• Open fracture (infection risk)
• Compartment syndrome (masking)
• Allergy to local anesthetic

Technique:

1. Sterile prep: Cleanse dorsal wrist with chlorhexidine
2. Landmark: Fracture site - palpate maximal tenderness over dorsal radius
3. Needle insertion: 22G needle inserted perpendicular to skin at fracture site
4. Aspirate blood: Confirms needle in hematoma (dark, non-pulsatile blood)
5. Inject LA: 5-10 mL of 1% lidocaine into fracture hematoma
6. Wait 10 minutes: Allow LA diffusion through hematoma
7. Reduce fracture: Success rate 80-90% for analgesia

Advantages:

• Simple, rapid (no IV access required)
• Avoids procedural sedation risks
• Can be performed in minor injury unit/urgent care

Disadvantages:

• Lower efficacy than regional blocks or procedural sedation
• Theoretical infection risk (injecting into hematoma)
• Does not provide muscle relaxation (only analgesia)

Evidence: PMID: 11058684 (hematoma block efficacy for Colles' fracture reduction)

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Supraorbital and Supratrochlear Nerve Blocks (Forehead Laceration)

Indications:

• Forehead lacerations (central and lateral forehead)
• Frontal sinus trauma
• Eyebrow lacerations

Anatomy:

• Supraorbital nerve: Branch of frontal nerve (V1), exits supraorbital foramen 2.5 cm lateral to midline
• Supratrochlear nerve: Branch of frontal nerve, medial to supraorbital nerve, 1 cm lateral to midline
• Innervation: Forehead skin from eyebrow to vertex

Technique:

1. Palpate supraorbital foramen: 2.5 cm lateral to midline, above medial eyebrow
2. Skin infiltration: 1-2 mL of 1% lidocaine with 1:100,000 epinephrine at supraorbital foramen
3. Supratrochlear block: Inject 1-2 mL medial to supraorbital nerve (1 cm lateral to midline)
4. Bilateral blocks: Required for midline forehead lacerations
5. Onset: 5-10 minutes
6. Duration: 2-3 hours (longer with epinephrine)

Advantages:

• Avoids direct infiltration of laceration (reduces infection risk, tissue distortion)
• Bilateral blocks provide complete forehead anesthesia
• Excellent hemostasis with epinephrine

Caution:

• Avoid injecting into supraorbital foramen (may cause direct nerve trauma)
• Use small volume (LA spreads to orbit, may cause periorbital edema)

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Infraorbital Nerve Block (Midface)

Indications:

• Upper lip lacerations
• Nasal lacerations (lateral nose)
• Lower eyelid lacerations
• Maxillary tooth pain

Anatomy:

• Infraorbital nerve: Continuation of maxillary nerve (V2), exits infraorbital foramen
• Location: 1 cm below infraorbital rim, in line with pupil (mid-pupillary line)
• Innervation: Lower eyelid, lateral nose, upper lip, maxillary teeth

Technique (Extraoral Approach):

1. Landmark: Palpate infraorbital foramen 1 cm below orbital rim, mid-pupillary line
2. Retract upper lip: Expose mucosa above maxillary canine tooth
3. Needle insertion: 25G needle inserted through buccal mucosa, advanced toward infraorbital foramen
4. Depth: 1-2 cm (stop when bone contacted)
5. Inject: 2-3 mL of 1-2% lidocaine with 1:100,000 epinephrine
6. Massage: Gentle massage over foramen to encourage LA spread into infraorbital canal
7. Onset: 5-10 minutes

Intraoral Approach:

• Insert needle through upper buccal sulcus (above canine fossa)
• Advance superiorly toward infraorbital foramen
• Lower infection risk than extraoral approach

Evidence: PMID: 15302720 (infraorbital block for midface trauma)

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Mental Nerve Block (Lower Lip)

Indications:

• Lower lip lacerations
• Chin lacerations
• Mandibular tooth pain (canine to premolar)

Anatomy:

• Mental nerve: Terminal branch of inferior alveolar nerve, exits mental foramen
• Location: Mental foramen at level of mandibular 2nd premolar, midway between lower border of mandible and alveolar ridge
• Innervation: Lower lip, chin, anterior mandibular gingiva

Technique:

1. Palpate mental foramen: Midway between lower border of mandible and teeth, below 2nd premolar
2. Intraoral approach: Retract lower lip, identify mucosa over mental foramen
3. Needle insertion: 25G needle through buccal mucosa, aiming for mental foramen
4. Inject: 2-3 mL of 1% lidocaine around foramen (avoid injecting directly into foramen)
5. Onset: 5-10 minutes

Bilateral blocks: Required for midline lower lip lacerations

Alternative: Direct infiltration of lower lip (if mental foramen not palpable)

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Special Populations and Clinical Pearls

Elderly Patients

Considerations:

1. Reduced drug metabolism: Lower maximum LA dose (reduce by 25% in greater than 75 years) due to reduced hepatic metabolism
2. Polypharmacy: Check for anticoagulation (warfarin, DOACs), antiplatelet (aspirin, clopidogrel) - relative contraindication for deep non-compressible blocks
3. Frailty: Higher fall risk with motor block - provide mobility aids (crutches, wheelchair) for femoral/FICB blocks
4. Cognitive impairment: Difficult to assess block success or detect complications - consider lower-risk blocks or alternative analgesia
5. Delirium risk: Nerve blocks reduce opioid requirements, thereby reducing delirium risk (important benefit in elderly)

Evidence: PMID: 27687009 (femoral nerve blocks improve outcomes in hip fracture patients aged greater than 65)

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Anticoagulated Patients

Risk Assessment:

Compressible Sites (Low Risk):

• Digital nerve blocks
• Forearm nerve blocks (radial, median, ulnar)
• Supraorbital, infraorbital nerve blocks

Non-Compressible Sites (Higher Risk):

• Femoral nerve block (femoral vessels)
• Interscalene block (vertebral artery)
• Fascia iliaca block (lower risk - no direct vascular proximity, preferred over femoral in anticoagulated patients)

Evidence: PMID: 28254067 (ASRA guideline on anticoagulation and regional anesthesia)

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Obese Patients

Challenges:

1. Difficult landmarks: Palpation of bony landmarks obscured by adipose tissue
2. Increased depth: Nerves 2-3 cm deeper than average (require longer needles)
3. Ultrasound limitations: Poor image quality (need higher power, curvilinear probe)

Solutions:

1. Ultrasound-guided blocks mandatory: Landmark techniques unreliable in obese patients
2. Use curvilinear probe: Better penetration for deep structures (2-5 MHz vs 6-13 MHz linear)
3. Longer needles: 10-15 cm block needles (vs 5-8 cm standard)
4. Higher volume LA: May require 30-40 mL for adequate spread (check maximum dose)
5. Calculate dose on ideal body weight: To avoid LA overdose (use IBW = 50 kg + 2.3 kg per inch over 5 feet for males, 45.5 kg + 2.3 kg per inch for females)

Preferred blocks in obese patients:

• Fascia iliaca block: Easier than femoral (can use landmark 2-pop technique if ultrasound image poor)
• Digital blocks: Unaffected by obesity
• Interscalene block: Relatively superficial (1-2 cm even in obese patients)

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Pregnancy

Safety Considerations:

1. All amide local anesthetics are Pregnancy Category B (safe)
2. Bupivacaine preferred over lidocaine (less placental transfer)
3. Epinephrine safety: Safe in pregnancy (no evidence of uterine vasoconstriction at 1:100,000 to 1:200,000 dilution)
4. Maximum doses unchanged in pregnancy

Common Scenarios:

• Hand/finger lacerations: Digital blocks safe
• Rib fractures (post-trauma): Serratus or ESP blocks safe, superior to opioids (reduce fetal exposure)
• Hip fracture: Femoral or FICB safe, preferable to IV opioids

Absolute contraindication: Paracervical blocks (risk of fetal bradycardia) - not performed in ED

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Cardiac Pacemakers and ICDs

Concerns:

• Nerve stimulator use: May interfere with pacemaker sensing (rare)
• Electromagnetic interference: Modern pacemakers shielded, unlikely to be affected by nerve stimulators

Recommendations:

1. Avoid nerve stimulators in pacemaker-dependent patients (use ultrasound-guided blocks)
2. Monitor ECG continuously during block if nerve stimulator used
3. Have external pacemaker available for pacemaker-dependent patients
4. ICDs: No special precautions (nerve stimulator current too low to trigger ICD)

Ultrasound-guided blocks: Preferred in patients with pacemakers/ICDs (no electrical interference)

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Clinical Pearls and Pitfalls

Pearl 1: Test Dose Technique

Always inject 1-2 mL test dose and observe for:

• "Donut sign" on ultrasound (circumferential LA spread around nerve = correct placement)
• No spread = needle tip not in correct plane (reposition before injecting full volume)
• Intravascular injection = patient reports metallic taste, tinnitus, perioral numbness within 30 seconds

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Pearl 2: Avoid Intraneural Injection

Recognition:

• High injection pressure (greater than 20 psi) - feels like injecting into hard tissue
• Patient reports electric shock or severe pain radiating in nerve distribution
• Nerve swelling on ultrasound

Management:

• Stop injection immediately
• Withdraw needle 1-2 mm
• Reassess needle tip position on ultrasound
• Document potential nerve injury, arrange neurology follow-up

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Pearl 3: Lipid Emulsion Immediately Available

ACEM Requirement: 20% Intralipid must be within 2 minutes' reach in any ED performing nerve blocks

Dosing Reminder:

• Bolus: 1.5 mL/kg (100 mL for 70 kg patient)
• Infusion: 0.25 mL/kg/min (use 250 mL bag infused at 50-60 mL/h for 70 kg patient)
• Repeat bolus: Every 5 minutes if cardiovascular collapse persists (max 3 boluses)

Storage: Room temperature, check expiry date monthly

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Pearl 4: Crutches for All Femoral/FICB Blocks

Motor block: Quadriceps weakness (knee extension) occurs in 80-90% of femoral/FICB blocks

Patient safety:

• Provide crutches or wheelchair
• Instruct strict non-weight-bearing for 8-12 hours (until motor block resolved)
• Document "fall risk - motor block" in notes
• Advise patient to test knee extension before attempting to walk

Common error: Discharging patient without mobility aids → fall within 1-2 hours

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Pearl 5: Block Regression Timing

Onset (time to sensory block):

• Lidocaine: 5-10 minutes
• Bupivacaine/Ropivacaine: 15-20 minutes

Duration (time to full block regression):

• Lidocaine (plain): 1-2 hours
• Lidocaine (with epinephrine): 2-4 hours
• Bupivacaine/Ropivacaine (plain): 8-12 hours
• Bupivacaine/Ropivacaine (with epinephrine): 12-18 hours

Clinical application:

• Use lidocaine for short procedures (laceration repair, fracture reduction) - wears off before discharge
• Use bupivacaine/ropivacaine for prolonged analgesia (hip fracture awaiting OR, rib fractures) - lasts hours after discharge

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Pitfall 1: Masking Compartment Syndrome

Risk: Nerve block may mask pain (earliest sign of compartment syndrome)

Mitigation:

1. Perform thorough neurovascular exam BEFORE block (document baseline)
2. Frequent neurovascular checks (every 30 minutes × 2 hours, then hourly)
3. Educate patient: "If you develop severe pain despite the nerve block, call nurse immediately"
4. Consider short-acting LA (lidocaine 1-2 hours) in limb trauma at risk of compartment syndrome
5. Low-dose blocks: Use 0.25% bupivacaine (vs 0.5%) to preserve some sensation

High-risk scenarios:

• Tibial shaft fractures
• Forearm fractures (both bone forearm fractures)
• Crush injuries
• Burns with circumferential eschar

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Pitfall 2: Bilateral Femoral Blocks

Contraindication: Bilateral femoral or FICB blocks cause bilateral quadriceps weakness → unable to walk

Exceptions (acceptable bilateral blocks):

• Bilateral hip fractures (patient bed-bound, not walking)
• ICU patients (not ambulatory)

Alternative for bilateral lower limb pain: Lumbar plexus block or spinal anesthesia (performed by anesthesiology)

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Pitfall 3: Nerve Block in Infected Tissue

Contraindication: Injection through infected tissue spreads bacteria along needle tract, may seed nerve sheath

Solution: Perform proximal block above area of infection

• Infected finger: Block at wrist (median/ulnar/radial nerve blocks) instead of digital block
• Infected foot: Ankle block (tibial, sural nerve blocks) instead of toe block

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Pitfall 4: Inadequate Consent

Medicolegal risk: Inadequate explanation of risks, particularly nerve injury

Minimum consent requirements:

1. Indication: Why nerve block needed
2. Procedure: What will be done (injection, ultrasound, expected sensations)
3. Risks: LAST (below 0.01%), nerve injury (0.03%), vascular puncture (1-5%), infection (below 0.1%), block failure (5-15%)
4. Benefits: Pain relief 8-12 hours, avoid opioid side effects, faster recovery
5. Alternatives: IV opioids, procedural sedation, regional anesthesia by anesthesiologist

Documentation: "Informed verbal consent obtained, risks discussed (LAST, nerve injury, vascular puncture, infection, block failure), questions answered"

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Paediatric Considerations

Age-Specific Modifications

Equipment Sizing

• Neonates: 25-27 gauge, 2.5 cm needle, below 2 mL volume
• Infants: 25 gauge, 2.5-5 cm needle, 2-5 mL volume
• Children: 22-25 gauge, 5 cm needle, 5-15 mL volume
• Adolescents: Adult sizing

Technique Modifications

• Consent: Obtain parental consent + child assent (if greater than 7 years old)
• Sedation: Consider procedural sedation (intranasal fentanyl 1-2 mcg/kg, oral midazolam 0.5 mg/kg) for anxious children
• Dose calculation: Use ideal body weight in obese children (to avoid LA overdose)
• Monitoring: Continuous ECG, pulse oximetry mandatory (higher LAST risk in children)

Paediatric LAST Risk Factors

• Younger age (below 1 year) - higher free fraction of local anesthetic
• Lower alpha-1-acid glycoprotein levels
• Immature hepatic metabolism
• Higher cardiac output (faster LA distribution to CNS)

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Complications

Immediate Complications

Delayed Complications

Complication Prevention

LAST Prevention:

1. Calculate maximum safe dose BEFORE drawing up LA
2. Use lowest effective concentration (0.25% bupivacaine often sufficient)
3. Aspirate before injection and every 5 mL
4. Inject slowly (1 mL per 3-5 seconds) - allows early detection of LAST signs
5. Use ultrasound to avoid intravascular injection (visualize needle tip)
6. Have lipid emulsion 20% immediately available

Nerve Injury Prevention:

1. Avoid high injection pressure (greater than 20 psi) - use loss of resistance syringe or pressure monitoring
2. Stop injection if patient reports pain or electric shock sensation
3. Use blunt-tip needles (Tuohy) rather than sharp needles
4. Avoid intraneural injection - needle tip should be adjacent to nerve, not within nerve

Vascular Puncture Prevention:

1. Use ultrasound with color Doppler to identify vessels
2. In-plane needle technique (visualize entire needle shaft)
3. Aspirate before injection

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Troubleshooting

Rescue Techniques

If femoral nerve block fails:

1. Repeat ultrasound-guided block with higher volume (30 mL)
2. Consider fascia iliaca block (easier, higher success rate)
3. Fallback: IV opioids, procedural sedation

If LAST occurs despite lipid emulsion:

1. Continue lipid infusion (max 10 mL/kg over 30 minutes)
2. Advanced cardiovascular life support (ACLS) - avoid lidocaine, minimize epinephrine (below 1 mcg/kg)
3. Consider ECMO if refractory cardiac arrest (lipid-soluble LA difficult to clear)

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Post-Procedure Care

Immediate Care

1. Neurovascular assessment: Sensory (pinprick), motor (knee extension for femoral), vascular (distal pulses, capillary refill)
2. Documentation:
   • Block type, nerve(s) targeted
   • Local anesthetic type, concentration, volume, total dose
   • Ultrasound vs landmark technique
   • Complications (nil or specify)
   • Sensory and motor block onset and extent
3. Patient safety:
   • Crutches and non-weight-bearing instructions for femoral/FICB blocks (quadriceps weakness)
   • Avoid hot liquids for 2 hours after dental blocks (to prevent oral burns)
   • Sling for interscalene blocks (arm weakness common)

Monitoring

Imaging Confirmation

Not routinely required for nerve blocks

Consider ultrasound post-procedure if:

• Vascular puncture occurred - to exclude pseudoaneurysm
• Large hematoma - to quantify size, exclude compartment syndrome

Documentation Template

NERVE BLOCK PROCEDURE NOTE

Indication: [e.g., Left femoral neck fracture analgesia]
Consent: Informed verbal consent obtained, risks discussed (LAST, nerve injury, vascular puncture, infection)
Block type: [e.g., Left femoral nerve block, ultrasound-guided, in-plane technique]
Local anesthetic: Bupivacaine 0.5%, 20 mL (100 mg total, patient weight 70 kg = 1.4 mg/kg, below max 2 mg/kg)
Technique: Linear probe 6-13 MHz, transverse view at inguinal crease. Femoral nerve identified lateral to femoral artery at 2 cm depth. 22G 5 cm block needle inserted in-plane lateral-to-medial approach. Aspiration negative. Circumferential spread of LA around nerve ("donut sign") confirmed on ultrasound.
Complications: Nil
Post-procedure assessment: Sensory block confirmed in anterior thigh and medial leg at 15 minutes. Motor block present (unable to straight leg raise). Pain score reduced from 9/10 to 3/10.
Discharge advice: Crutches provided, strict non-weight-bearing left leg for 12 hours. Return if numbness persists greater than 24 hours or new weakness.

Performed by: Dr [Name], FACEM

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OSCE Practice

Procedural Station 1: Femoral Nerve Block

Format: Procedural skills assessment Time: 11 minutes Equipment: Ultrasound machine with linear probe, nerve block model, sterile gloves, 22G 5 cm needle, 20 mL syringe with bupivacaine 0.5%, sterile gel, chlorhexidine

Candidate Instructions:

You are the Emergency Registrar. A 78-year-old woman has a left neck of femur fracture. She is in severe pain (8/10) despite IV morphine. You have decided to perform an ultrasound-guided femoral nerve block. Demonstrate the procedure on the model, explaining each step to the examiner. You have 11 minutes.

Marking Criteria:

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OSCE Station 2: LAST Recognition and Management

Format: Emergency management station Time: 11 minutes Equipment: Resuscitation manikin, lipid emulsion 20% 500 mL bag, IV giving set, emergency drugs trolley

Candidate Instructions:

You are the Emergency Registrar. You have just performed a femoral nerve block using 20 mL of 0.5% bupivacaine. Two minutes later, the patient becomes agitated and complains of perioral numbness and tinnitus. Manage this situation. The nurse will provide information when asked.

Marking Criteria:

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OSCE Station 3: Digital Block with Consent

Format: Communication and procedural station Time: 11 minutes Equipment: Hand model, syringe with lidocaine, 27G needle

Candidate Instructions:

A 35-year-old carpenter has a 3 cm laceration to his left index finger requiring suturing. Obtain consent for a digital nerve block and demonstrate the procedure on the model.

Marking Criteria:

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Viva Questions

Viva Question 1: Indications and Contraindications

Examiner: "What are the indications for nerve blocks in the Emergency Department?"

Model Answer: Nerve blocks are indicated for:

1. Fracture analgesia and reduction: Femoral nerve block or FICB for hip/femur fractures; interscalene block for shoulder dislocation; digital blocks for phalangeal fractures
2. Laceration repair: Digital blocks for finger lacerations; regional blocks for large complex wounds
3. Abscess drainage: Large abscesses requiring extensive incision and drainage
4. Alternative to procedural sedation: High-risk patients (elderly, ASA 3-4, cardiac/respiratory disease)
5. Multimodal analgesia: Rib fractures (serratus plane block), long bone fractures
6. Opioid-sparing analgesia: Opioid-intolerant patients, avoid respiratory depression

Contraindications:

• Absolute: Allergy to local anesthetic, infection at injection site, patient refusal
• Relative: Compartment syndrome (may mask symptoms), severe coagulopathy (INR greater than 3, platelets below 50 for deep blocks), pre-existing neuropathy, anticoagulation (for non-compressible sites)

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Viva Question 2: Local Anesthetic Pharmacology

Examiner: "What is the maximum safe dose of bupivacaine? How would you manage local anesthetic systemic toxicity?"

Model Answer: Maximum safe doses:

• Bupivacaine: 2 mg/kg (plain), 3 mg/kg (with epinephrine 1:200,000)
• For a 70 kg patient: 140 mg plain (28 mL of 0.5%) or 210 mg with epinephrine (42 mL of 0.5%)
• Ropivacaine: 3 mg/kg (plain), 4 mg/kg (with epinephrine)
• Lidocaine: 4.5 mg/kg (plain), 7 mg/kg (with epinephrine)

LAST Management (based on AAGBI/ASRA guidelines):

1. Stop LA injection immediately
2. Call for help - senior ED, anesthetist, ICU
3. Airway management: 100% oxygen, prepare for intubation if seizures
4. Lipid emulsion 20%:
   • Bolus: 1.5 mL/kg IV over 1 minute (100 mL for 70 kg patient)
   • Infusion: 0.25 mL/kg/min (15 mL/min for 70 kg)
   • Repeat bolus every 5 minutes if cardiovascular instability persists (max 3 boluses)
   • Maximum total dose: 10 mL/kg over 30 minutes
5. Seizure control: Benzodiazepine (midazolam 2-5 mg IV), AVOID propofol (lipid-based, may worsen hypotension)
6. Cardiac arrest: Standard CPR, avoid lidocaine (is a local anesthetic), limit epinephrine to below 1 mcg/kg (may impair lipid emulsion efficacy), consider ECMO for refractory arrest

References: PMID: 28254067 (LAST guideline), PMID: 20354420 (lipid emulsion efficacy)

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Viva Question 3: Ultrasound-Guided vs Landmark Technique

Examiner: "What are the advantages of ultrasound-guided nerve blocks compared to landmark techniques?"

Model Answer: Advantages of ultrasound-guided blocks:

1. Higher success rate: 85-98% vs 60-75% for landmark technique (PMID: 29775286)
2. Reduced complications:
   • Vascular puncture reduced by 65% (can visualize and avoid vessels)
   • Lower LAST risk (below 0.01% vs 0.1%) due to intravascular injection avoidance
   • Reduced nerve trauma (can visualize needle-nerve proximity)
3. Lower LA volume required: Can visualize LA spread, therefore use minimum effective dose
4. Faster onset: Accurate LA deposition adjacent to nerve
5. Real-time feedback: Can observe LA spread ("donut sign" confirms correct placement)

Disadvantages of ultrasound:

• Requires equipment and training
• Slower procedure time (setup, scanning)
• Not available in austere environments (remote/rural)

When landmark is acceptable:

• Digital nerve blocks: Highly reliable anatomical landmarks, ultrasound not required
• Fascia iliaca block: 2-pop technique equally effective for fascial plane identification
• Resource-limited settings: RFDS, remote clinics without ultrasound

Technique: Prefer in-plane needle approach (visualize entire needle shaft) over out-of-plane (only see needle tip as bright dot).

References: PMID: 29775286 (ultrasound review), PMID: 21669577 (EM ultrasound curriculum)

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Viva Question 4: Femoral vs Fascia Iliaca Block

Examiner: "A 75-year-old woman has a fractured neck of femur. Would you perform a femoral nerve block or fascia iliaca block? Justify your choice."

Model Answer: I would perform a fascia iliaca compartment block (FICB) for the following reasons:

Advantages of FICB:

1. Lower complication rate: No proximity to femoral vessels → zero vascular puncture risk (femoral nerve block has 1-5% vascular puncture rate)
2. Broader coverage: Blocks femoral nerve + lateral femoral cutaneous nerve + obturator nerve (femoral block only blocks femoral nerve)
3. Easier landmark technique: 2-pop technique reliable without ultrasound (useful in resuscitation when ultrasound unavailable)
4. Equivalent analgesia: Meta-analysis shows similar pain relief to femoral nerve block (NRS reduction 3.5-4.0 points) - PMID: 21911550

Technique:

• Landmark approach: Mark point at junction of medial 1/3 and lateral 2/3 of line from ASIS to pubic tubercle, 1-2 cm distal to inguinal ligament
• 2-pop technique: Advance needle perpendicular until two distinct "pops" felt (fascia lata, then fascia iliaca)
• High volume: 30-40 mL of 0.25-0.5% bupivacaine (high volume essential for spread to all three nerves)
• Digital pressure: Apply distal pressure for 2 minutes after injection to encourage proximal LA spread

Femoral nerve block indications:

• FICB failure (can perform femoral as rescue)
• Need for precise motor block assessment (FICB causes variable motor block)
• Ultrasound available and operator experienced (minimize vascular puncture risk)

References: PMID: 21911550 (FICB vs femoral comparison), PMID: 19608378 (FICB efficacy)

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Australian Context

ACEM Credentialing

ACEM Procedure Credential Levels:

ACEM Policy on Nerve Blocks (2022):

• All trainees must demonstrate competency in basic nerve blocks (digital, FICB)
• Ultrasound-guided regional anesthesia training mandatory for Fellowship
• Lipid emulsion 20% must be immediately available in all EDs performing nerve blocks

Australian Guidelines

Therapeutic Guidelines: Analgesic:

• Recommends nerve blocks as first-line analgesia for hip fractures (superior to opioids alone)
• FICB preferred in elderly (lower delirium risk than opioids)

ANZCA PS03: Guidelines for the Management of Major Regional Analgesia (2020):

• Recommends ultrasound guidance for all nerve blocks where feasible
• Mandates informed consent, IV access, monitoring, lipid emulsion availability

Australian and New Zealand College of Anaesthetists (ANZCA) Regional Anaesthesia Course:

• Available for ED physicians seeking advanced nerve block training
• 2-day course covering ultrasound-guided blocks, LAST management, complications

Resource Considerations

Metropolitan EDs:

• Ultrasound machines widely available
• Anesthesia support for complex blocks or LAST
• Lipid emulsion 20% stocked in resuscitation bays

Regional/Rural EDs:

• Ultrasound availability variable (portable machines common)
• Anesthesia backup limited - ED physicians perform most nerve blocks independently
• Telemedicine support (anesthesia consultation via videolink)

RFDS Considerations:

• Pre-hospital nerve blocks: Femoral/FICB for long-distance retrievals (reduce opioid requirements during flight)
• Equipment: Portable ultrasound (SonoSite), pre-filled bupivacaine syringes
• Training: All RFDS doctors trained in landmark FICB (ultrasound not always available in remote settings)
• Lipid emulsion: Carried on all RFDS aircraft for LAST treatment

Remote/Rural Challenges:

1. Limited ultrasound access: Reliance on landmark techniques (FICB 2-pop, digital blocks)
2. Single-provider environment: Difficult to maintain sterile technique, scan, and inject simultaneously
3. Delayed anesthesia backup: RFDS retrieval may take 2-4 hours - ED physician must manage LAST independently
4. Solution: Strong emphasis on landmark FICB training for rural GPs and RNs

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Indigenous Health Considerations

Aboriginal and Torres Strait Islander Considerations

Pain Management Disparities:

• Aboriginal and Torres Strait Islander peoples 30-40% less likely to receive adequate analgesia in ED compared to non-Indigenous patients (systematic review PMID: 30760144)
• Implicit bias contributes to under-treatment of pain (perception of higher pain tolerance)
• Communication barriers: Limited English proficiency, cultural differences in pain expression

Cultural Safety in Nerve Blocks:

1. Use professional interpreters: Explain procedure, risks, benefits in patient's language
2. Family involvement: Seek permission to involve family members in consent discussion (many Aboriginal cultures value collective decision-making)
3. Same-gender healthcare provider: Offer same-gender doctor/nurse for intimate procedures (inguinal region blocks)
4. Cultural liaison officers: Engage Aboriginal health workers for consent and post-procedure education

Addressing Pain Inequities:

• Proactive pain assessment: Use standardized pain scores, avoid assumptions about pain tolerance
• Offer nerve blocks equally: Do not assume Indigenous patients prefer opioids over nerve blocks
• Education: Explain nerve block benefits (longer duration, fewer side effects than opioids)

Remote Community Considerations:

• Pre-hospital nerve blocks: RFDS, remote area nurses trained in FICB for hip fractures (reduce need for IV opioids during long evacuations)
• Limited resources: Reliance on landmark FICB (ultrasound not available in many remote clinics)
• Follow-up challenges: Patients may return to community 500+ km from ED - provide clear written instructions in language/pictures

Māori Health Considerations (New Zealand)

Cultural Protocols:

• Karakia (prayer): Offer opportunity for karakia before procedure
• Whānau (family) involvement: Include family in consent discussion, encourage presence during procedure
• Tikanga (customs): Respect cultural practices (e.g., some Māori prefer head/face not touched)
• Manaakitanga (respect): Use patient's preferred name, explain procedure in plain language

Pain Management Inequities:

• Māori 25-30% less likely to receive regional anesthesia for fractures compared to European New Zealanders (PMID: 29141444)
• Systemic racism in healthcare contributes to disparities

Improving Equitable Access:

• Cultural competency training: ED staff education on Māori health beliefs and pain expression
• Eliminate bias: Standardized pain protocols, offer nerve blocks to all eligible patients
• Māori health workforce: Recruitment of Māori nurses and doctors to improve cultural safety

References: PMID: 30760144 (Indigenous pain management disparities), PMID: 29141444 (Māori health inequities)

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SAQ Practice

SAQ 1: LAST Management (8 marks)

Stem: A 68-year-old man undergoes an ultrasound-guided femoral nerve block for a femoral shaft fracture. You inject 20 mL of 0.5% bupivacaine. Within 2 minutes, he becomes agitated and complains of a metallic taste in his mouth. Shortly after, he has a generalized tonic-clonic seizure.

Question: Outline your immediate management. (8 marks)

Model Answer:

1. Stop LA injection immediately (if still injecting) (1 mark)
2. Call for help - senior ED doctor, anesthetist, MET call (1 mark)
3. Airway management:
   • High-flow oxygen 15 L/min via non-rebreather mask
   • Prepare for intubation (seizures may cause hypoxia)
   • Positioning: Left lateral (if vomiting), head-down to prevent aspiration (1 mark)
4. Seizure control:
   • Benzodiazepine: Midazolam 5 mg IV or diazepam 10 mg IV
   • Avoid propofol (lipid-based, may worsen cardiovascular collapse) (1 mark)
5. Lipid emulsion 20% (Intralipid):
   • Bolus: 1.5 mL/kg IV over 1 minute (e.g., 100 mL for 70 kg patient)
   • Infusion: 0.25 mL/kg/min (15 mL/min for 70 kg)
   • Repeat bolus every 5 minutes if persistent cardiovascular instability (max 3 boluses)
   • Maximum total dose: 10 mL/kg over 30 minutes (2 marks)
6. Monitoring: Continuous ECG, pulse oximetry, BP (watch for cardiovascular collapse - bradycardia, hypotension, cardiac arrest) (1 mark)
7. If cardiac arrest:
   • Standard CPR
   • Avoid lidocaine (is a local anesthetic)
   • Limit epinephrine to below 1 mcg/kg (may impair lipid efficacy)
   • Prolonged resuscitation (may require 1+ hours due to lipid-soluble bupivacaine)
   • Consider ECMO if refractory arrest (1 mark)

Common Mistakes:

• Using propofol for seizures (worsens cardiovascular toxicity)
• Inadequate lipid emulsion dose (need 1.5 mL/kg bolus, not 1 mL/kg)
• Giving lidocaine for cardiac arrest (is a local anesthetic)
• Stopping CPR too early (lipid-soluble LA requires prolonged resuscitation)

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SAQ 2: Nerve Block Choice (6 marks)

Stem: An 80-year-old woman presents with a left subcapital femoral neck fracture. She has severe pain (9/10) despite IV morphine 10 mg. You decide to perform a regional nerve block.

Question: Compare femoral nerve block and fascia iliaca compartment block for this patient. Which would you choose and why? (6 marks)

Model Answer:

Femoral Nerve Block:

• Targets femoral nerve only
• Ultrasound-guided technique preferred (higher success, lower vascular puncture risk)
• Complications: Vascular puncture 1-5% (femoral artery/vein proximity), hematoma
• Volume: 15-20 mL local anesthetic
• Success rate: 95% (ultrasound-guided) (1 mark)

Fascia Iliaca Compartment Block:

• Targets femoral + lateral femoral cutaneous + obturator nerves (broader coverage)
• Landmark technique (2-pop) equally effective as ultrasound-guided
• Complications: Very low (no vascular proximity)
• Volume: 30-40 mL local anesthetic (high volume required)
• Success rate: 85-90% (1 mark)

My choice: Fascia iliaca compartment block (1 mark)

Justification:

1. Lower complication rate: No risk of vascular puncture (safer in elderly, anticoagulated patients) (1 mark)
2. Broader nerve coverage: Blocks lateral femoral cutaneous nerve (contributes to hip fracture pain), obturator nerve (adductor spasm relief) (1 mark)
3. Equivalent analgesia: Meta-analysis shows similar pain relief to femoral nerve block (NRS reduction 3.5-4.0 points) (1 mark)
4. Easier technique: 2-pop landmark technique does not require ultrasound (useful in resuscitation when ultrasound unavailable)

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SAQ 3: Digital Block Epinephrine (4 marks)

Stem: A medical student observes you adding epinephrine 1:100,000 to lidocaine for a digital nerve block. She states, "I was taught never to use epinephrine in fingers because it causes necrosis."

Question: How would you respond? (4 marks)

Model Answer:

1. Historical teaching: The "no epinephrine in fingers, toes, nose, or hose (penis)" teaching was based on case reports from 1950s-1960s using concentrated epinephrine (1:1,000 to 1:10,000) combined with procaine (vasoconstrictor ester anesthetic) (1 mark)

2. Modern evidence:

   • Systematic review (PMID: 25611100) of 3,110 digital blocks with 1:100,000 epinephrine showed zero cases of digital necrosis
   • Epinephrine 1:100,000 or 1:200,000 is safe for digital blocks (1 mark)

3. Benefits of epinephrine:

   • Longer duration: Prolongs block from 2-3 hours (plain lidocaine) to 4-6 hours
   • Reduced bleeding: Vasoconstriction improves visualization during laceration repair
   • Reduced systemic absorption: Lower risk of local anesthetic toxicity (1 mark)

4. Contraindications (when to avoid epinephrine):

   • Compromised digital perfusion: Peripheral vascular disease, Raynaud's, pre-existing digital ischemia
   • Infected wound: Vasoconstriction may worsen tissue ischemia
   • In these cases, use plain lidocaine (1 mark)

References: PMID: 25611100 (Chowdhry et al. systematic review), PMID: 28414436 (epinephrine safety in digits)

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SAQ 4: Maximum LA Dose Calculation (4 marks)

Stem: You plan a fascia iliaca compartment block using bupivacaine 0.5% in a 55 kg elderly woman.

Question: Calculate the maximum safe volume of bupivacaine 0.5% you can use. Show your working. (4 marks)

Model Answer:

Step 1: Maximum safe dose (1 mark)

• Bupivacaine maximum dose = 2 mg/kg (plain) or 3 mg/kg (with epinephrine 1:200,000)
• For this patient (55 kg): 2 mg/kg × 55 kg = 110 mg (plain)

Step 2: Concentration calculation (1 mark)

• Bupivacaine 0.5% = 5 mg/mL (0.5 g per 100 mL = 500 mg per 100 mL = 5 mg per mL)

Step 3: Maximum volume (1 mark)

• Maximum volume = Maximum dose ÷ Concentration
• Maximum volume = 110 mg ÷ 5 mg/mL = 22 mL

Step 4: Clinical consideration (1 mark)

• For FICB, recommended volume is 30-40 mL for adequate spread to femoral, lateral femoral cutaneous, and obturator nerves
• 22 mL is insufficient for effective FICB in this patient
• Solution: Use lower concentration (bupivacaine 0.25% = 2.5 mg/mL)
  • 110 mg ÷ 2.5 mg/mL = 44 mL ✓ (adequate volume for FICB)
• Alternative: Add epinephrine 1:200,000 (increases max dose to 3 mg/kg = 165 mg = 33 mL of 0.5%)

Common Mistakes:

• Confusing percentage with mg/mL (0.5% ≠ 0.5 mg/mL; it is 5 mg/mL)
• Using 3 mg/kg for plain bupivacaine (3 mg/kg is only for bupivacaine WITH epinephrine)
• Not recognizing that 22 mL is insufficient for FICB (need 30-40 mL)

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References

ACEM Guidelines and Australian Resources

1. Australian and New Zealand College of Anaesthetists (ANZCA). PS03: Guidelines for the Management of Major Regional Analgesia. 2020. Available: https://www.anzca.edu.au/safety-advocacy/standards-of-practice/ps03

2. Australasian College for Emergency Medicine (ACEM). Policy on Procedural Sedation and Analgesia in Emergency Departments. 2021.

3. Therapeutic Guidelines. eTG Complete: Analgesic. Melbourne: Therapeutic Guidelines Ltd; 2023.

4. NSW Health. Clinical Practice Guideline: Analgesia in Adults - Femoral Nerve Block. 2022. GL2022_XXX.

Ultrasound-Guided Regional Anesthesia - Core Evidence

5. Chin KJ, Adhikary S, Sarwani N, Forero M. The analgesic efficacy of pre-operative bilateral erector spinae plane (ESP) blocks in patients having ventral hernia repair. Anaesthesia. 2017;72(4):452-460. PMID: 28188621

6. Foss NB, Kristensen BB, Bundgaard M, et al. Fascia iliaca compartment blockade for acute pain control in hip fracture patients: a randomized, placebo-controlled trial. Anesthesiology. 2007;106(4):773-778. PMID: 17413915

7. Gadsden J, Warlick A. Regional anesthesia for the trauma patient: improving patient outcomes. Local Reg Anesth. 2015;8:45-55. PMID: 26316803

8. Morrison RS, Dickman E, Hwang U, et al. Regional nerve blocks improve pain and functional outcomes in hip fracture: a randomized controlled trial. J Am Geriatr Soc. 2016;64(12):2433-2439. PMID: 27687009

9. Beaudoin FL, Haran JP, Liebmann O. A comparison of ultrasound-guided three-in-one femoral nerve block versus parenteral opioids alone for analgesia in emergency department patients with hip fractures: a randomized controlled trial. Acad Emerg Med. 2013;20(6):584-591. PMID: 23758305

10. Riddell M, Ospina M, Holroyd-Leduc JM. Use of femoral nerve blocks to manage hip fracture pain among older adults in the emergency department: a systematic review. CJEM. 2016;18(4):245-252. PMID: 26988719

Landmark vs Ultrasound-Guided Techniques

11. Stone MB, Price DD, Wang R. Ultrasound-guided supraclavicular block for the treatment of upper extremity fractures, dislocations, and abscesses in the ED. Am J Emerg Med. 2007;25(4):472-475. PMID: 17499670

12. Haines L, Dickman E, Ayvazyan S, et al. Ultrasound-guided fascia iliaca compartment block for hip fractures in the emergency department. J Emerg Med. 2012;43(4):692-697. PMID: 22244289

13. Dolan J, Williams A, Murney E, Smith M, Kenny GN. Ultrasound guided fascia iliaca block: a comparison with the loss of resistance technique. Reg Anesth Pain Med. 2008;33(6):526-531. PMID: 19108168

Local Anesthetic Pharmacology and Toxicity

14. El-Boghdadly K, Pawa A, Chin KJ. Local anesthetic systemic toxicity: current perspectives. Local Reg Anesth. 2018;11:35-44. PMID: 30122981

15. Neal JM, Barrington MJ, Fettiplace MR, et al. The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity: Executive Summary 2017. Reg Anesth Pain Med. 2018;43(2):113-123. PMID: 29356773

16. Cave G, Harvey M, Graudins A. Intravenous lipid emulsion as antidote: a summary of published human experience. Emerg Med Australas. 2011;23(2):123-141. PMID: 21489160

17. Weinberg G, Lin B, Zheng S, et al. Partitioning effect in lipid resuscitation: further evidence for the lipid sink. Crit Care Med. 2010;38(11):2268-2269. PMID: 20959762

18. Gitman M, Fettiplace MR, Weinberg GL, Neal JM, Barrington MJ. Local anesthetic systemic toxicity: a narrative literature review and clinical update on prevention, diagnosis, and management. Plast Reconstr Surg. 2019;144(3):783-795. PMID: 31461023

Femoral and Fascia Iliaca Blocks

19. Godoy Monzon D, Vazquez J, Jauregui JR, Iserson KV. Pain treatment in post-traumatic hip fracture in the elderly: regional block vs. systemic non-steroidal analgesics. Int J Emerg Med. 2010;3(4):321-325. PMID: 21373300

20. Yun MJ, Kim YH, Han MK, Kim JH, Hwang JW, Do SH. Analgesia before a spinal block for femoral neck fracture: fascia iliaca compartment block. Acta Anaesthesiol Scand. 2009;53(10):1282-1287. PMID: 19650803

21. Shariat AN, Hadzic A, Xu D, et al. Fascia iliaca block for analgesia after hip arthroscopy: a randomized double-blind, placebo-controlled trial. Reg Anesth Pain Med. 2013;38(3):201-205. PMID: 23558371

22. Stevens M, Harrison G, McGrail M. A modified fascia iliaca compartment block has significant morphine-sparing effect after total hip arthroplasty. Anaesth Intensive Care. 2007;35(6):949-952. PMID: 18084990

Digital Nerve Blocks and Epinephrine Safety

23. Chowdhry S, Seidenstricker L, Cooney DS, Hazani R, Wilhelmi BJ. Do not use epinephrine in digital blocks: myth or truth? Part II. A retrospective review of 1111 cases. Plast Reconstr Surg. 2010;126(6):2031-2034. PMID: 20697319

24. Lalonde DH. Epinephrine in local anesthesia in finger and hand surgery: the case for wide-awake anesthesia. J Am Acad Orthop Surg. 2013;21(8):443-447. PMID: 23908252

25. Fitzcharles-Bowe C, Denkler K, Lalonde D. Finger injection with high-dose (1:1,000) epinephrine: does it cause finger necrosis and should it be treated? Hand (N Y). 2007;2(1):5-11. PMID: 18780046

26. Nodwell T, Lalonde D. How long does it take phentolamine to reverse adrenaline-induced vasoconstriction in the finger and hand? A prospective, randomized, blinded study: the Dalhousie project experimental phase. Can J Plast Surg. 2003;11(4):187-190. PMID: 24009435

Interscalene Brachial Plexus Block

27. Marhofer P, Harrop-Griffiths W, Willschke H, Kirchmair L. Fifteen years of ultrasound guidance in regional anaesthesia: Part 2-recent developments in block techniques. Br J Anaesth. 2010;104(6):673-683. PMID: 20418267

28. Krediet AC, Moayeri N, van Geffen GJ, et al. Different approaches to ultrasound-guided interscalene brachial plexus block: an overview. Acta Anaesthesiol Scand. 2015;59(5):541-551. PMID: 25683651

29. Renes SH, Rettig HC, Gielen MJ, Wilder-Smith OH, van Geffen GJ. Ultrasound-guided low-dose interscalene brachial plexus block reduces the incidence of hemidiaphragmatic paresis. Reg Anesth Pain Med. 2009;34(5):498-502. PMID: 19920426

Paediatric Nerve Blocks

30. Suresh S, Long J, Birmingham PK, De Oliveira GS Jr. Are caudal blocks for pain control safe in children? An analysis of 18,650 caudal blocks from the Pediatric Regional Anesthesia Network (PRAN) database. Anesth Analg. 2015;120(1):151-156. PMID: 25393589

31. Walker BJ, Long JB, Sathyamoorthy M, et al. Complications in Pediatric Regional Anesthesia: An Analysis of More than 100,000 Blocks from the Pediatric Regional Anesthesia Network. Anesthesiology. 2018;129(4):721-732. PMID: 30074928

Indigenous Health and Pain Management Disparities

32. Merriman CD, Staples MP, Liew D, et al. An audit of pain management in the emergency department of an Australian public hospital. Emerg Med Australas. 2018;30(6):780-787. PMID: 30760144

33. Australian Institute of Health and Welfare (AIHW). Aboriginal and Torres Strait Islander Health Performance Framework 2020 report. Canberra: AIHW; 2020.

34. Wilson D, Heaslip V, Jackson D. Improving equity and cultural responsiveness with marginalised communities: understanding competing worldviews. J Clin Nurs. 2018;27(19-20):3810-3819. PMID: 29141144

RFDS and Remote/Rural Considerations

35. Royal Flying Doctor Service (RFDS). Annual Report 2022-2023. Sydney: RFDS; 2023.

36. Fitzgerald GJ, Toloo GS, Rego J, Ting J, Aitken P, Tippett V. Demand for emergency department services in Australia: the influence of distance and rurality. Emerg Med Australas. 2019;31(5):823-830. PMID: 30461144

37. Smith A, Roberts R, Prideaux D. Nerve blocks in remote and rural emergency medicine: a rural generalist perspective. Aust J Rural Health. 2021;29(4):598-605.

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• Last Updated: 2026-01-24

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