What are the recommended nerve block techniques and medications for pain management in emergency medicine?

Nerve Block Techniques and Medications for Pain Management in Emergency Medicine

Regional anesthesia techniques through nerve blocks are strongly recommended as effective first-line interventions for pain management in emergency medicine, particularly for site-specific injuries, due to their superior analgesia and opioid-sparing effects. 1

Recommended Nerve Block Techniques by Anatomical Region

Upper Extremity Blocks

• Brachial Plexus Blocks:
  • Supraclavicular approach: Provides more consistent success (92% success rate) compared to axillary approach (56-86% success rate) 1
  • Axillary approach: Alternative when supraclavicular approach is contraindicated
  • Subclavian perivascular approach: Effective for surgical anesthesia with median duration of 11.4-14.4 hours 2

Lower Extremity Blocks

• Hip Fracture Blocks:

  • Fascia Iliaca Compartment Block (FICB): Superior to opioids for pain control during movement 1
  • Pericapsular Nerve Group (PENG) Block: Effective for hip fracture pain 3
  • Femoral Nerve Block: Reduces pain intensity and rescue analgesia requirements 4

• Knee Pain:

  • Genicular Nerve Block: Targets superior lateral, superior medial, and inferior medial genicular nerves for motor-sparing analgesia 5

Abdominal/Truncal Blocks

• Transversus Abdominis Plane (TAP) Block: Effective for laparoscopic and open abdominal surgery 1
• Rectus Sheath Block: Viable alternative to TAP block, especially for midline incisions 1

Digital Blocks

• Digital Nerve Block: Recommended for finger injuries including burns, providing complete anesthesia without tissue distortion 6

Recommended Medications and Dosing

Local Anesthetics

• Ropivacaine:

  • Concentration: 0.2% for analgesia, 0.5% for surgical anesthesia
  • Dosing: 5-250 mg depending on block type
  • Duration: 5-8 hours for major nerve blocks with 0.5% concentration 2
  • Advantages: Lower cardiotoxicity than bupivacaine

• Bupivacaine:

  • Concentration: 0.25-0.5%
  • Maximum dose: 2-3 mg/kg without epinephrine
  • Duration: Comparable to ropivacaine for brachial plexus blocks 2

• Lidocaine:

  • Concentration: 1% without epinephrine for digital blocks
  • Maximum dose: 4-5 mg/kg (not exceeding 300 mg total) 6
  • Onset: Faster than bupivacaine or ropivacaine
  • Duration: Shorter than bupivacaine or ropivacaine

Multimodal Analgesia Approach

Nerve blocks should be incorporated into a multimodal analgesia regimen:

1. First-line: Regional nerve blocks for site-specific pain
2. Base analgesia: Regular acetaminophen (up to 15 mg/kg every 6 hours, max 4g/day) 1
3. Adjuncts:
   • Low-dose ketamine (0.15-0.3 mg/kg) for opioid-sparing effect 1
   • NSAIDs with caution in elderly or those with renal impairment 1
4. Rescue analgesia: Limited opioids for breakthrough pain

Implementation Considerations

Timing and Duration

• Acute setting: Single-shot blocks provide 6-12 hours of analgesia
• Extended analgesia: Continuous catheter techniques can provide 3-4 days of pain relief 7
• Pre-procedural blocks: Consider nerve blocks before painful procedures or reductions 1

Technical Considerations

• Ultrasound guidance: Improves success rates and reduces complications 4, 8
• Time efficiency: Most blocks can be performed in under 5 minutes with proper training 8
• Pain relief onset: Majority of patients experience significant relief within 5 minutes 8

Special Populations

Elderly Patients

• Reduce opioid dosing by 20-25% per decade after age 55 1
• Peripheral nerve blocks reduce delirium risk compared to opioid-based regimens 3
• Avoid gabapentinoids in older patients undergoing major surgery 1

Trauma Patients

• Continuous nerve blocks can reduce hourly opioid use by approximately 58% 7
• Blocks provide superior analgesia for fracture pain compared to standard care 4

Pitfalls and Caveats

• Contraindications: Coagulopathy, infection at injection site, patient refusal
• Complications: Monitor for:
  • Intravascular injection
  • Local anesthetic systemic toxicity
  • Nerve injury
  • Infection
  • Hematoma
• Digital blocks: Avoid epinephrine-containing solutions in digits due to risk of ischemia 6
• Continuous catheters: Have a planned removal process and transition to oral analgesia 1

Nerve blocks in emergency medicine significantly reduce pain scores, decrease opioid requirements, and improve patient outcomes when performed correctly. The evidence strongly supports their routine use as part of standard emergency pain management protocols.