What are the recommendations for performing a brachial plexus block?

Recommendations for Performing a Brachial Plexus Block

Ultrasound guidance should be used for all brachial plexus blocks as the standard of care to improve success rates and reduce complications. 1, 2

Approach Selection

The choice of approach depends on the surgical site and patient factors:

1. Interscalene approach:

   • Best for shoulder and proximal upper arm procedures
   • Caution: High risk of phrenic nerve involvement (avoid in patients with respiratory compromise) 1

2. Supraclavicular approach:

   • Excellent alternative to interscalene with less respiratory impact
   • Higher success rates (92%) compared to axillary approach (56-86%) 3
   • Good option for patients with respiratory disease 1

3. Infraclavicular approach:

   • Effective for elbow, forearm, and hand procedures
   • Provides reliable anesthesia with 95% success rate when ultrasound-guided 4
   • Requires deeper needle insertion but avoids respiratory complications

4. Axillary approach:

   • Safest approach with minimal risk of pneumothorax or phrenic nerve involvement
   • Excellent for forearm and hand procedures
   • May miss musculocutaneous nerve (25% incomplete block rate) 5
   • Recommended for beginners learning ultrasound-guided techniques 6

Technical Considerations

Positioning

• Limit arm abduction to 90° in supine patients to prevent brachial plexus stretch injuries 7
• Use padded armboards to decrease risk of upper extremity neuropathy 7
• Consider chest rolls in laterally positioned patients to decrease risk of brachial plexus neuropathy 7

Equipment and Medication

• Use a high-frequency linear ultrasound probe for optimal visualization 6
• For single-shot blocks:
  • Ropivacaine 0.5% provides 3.7-8.7 hours of sensory block 3
  • Ropivacaine 0.75% provides 11.4-14.4 hours of anesthesia 3
• For continuous blocks:
  • Use ropivacaine 0.2-0.3% for infusion 1
  • Can provide analgesia for up to 48-72 hours 1

Technique

• Identify key anatomical structures (nerves, vessels) before needle insertion
• Use in-plane needle approach when possible for better visualization
• For humeral canal blocks, follow this sequence for optimal onset: median, ulnar, radial, musculocutaneous, and medial cutaneous nerves 8
• Consider dual guidance (ultrasound + nerve stimulation) for deep blocks 7

Safety Considerations

Monitoring

• Monitor patients for at least 30 minutes following local anesthetic injection 1
• Watch for signs of local anesthetic systemic toxicity (LAST)
• Maximum recommended dose of ropivacaine: 3 mg/kg 1
• Perform a simple postoperative assessment of extremity nerve function 7

Contraindications

• Central neuraxial anesthesia is contraindicated in patients on P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor) unless discontinued 5-7 days prior 7
• Peripheral nerve blocks with high bleeding risk (infraclavicular, parasacral) should be avoided in patients on P2Y12 inhibitors 7
• Low bleeding risk blocks (axillary, femoral, popliteal) may be performed in patients on antiplatelet therapy if benefit outweighs risk 7

Provider Presence

• An anesthetist may not need to remain present during surgery under peripheral regional anesthesia in certain defined circumstances 7
• The patient must be conscious and communicating effectively when responsibility is handed over 7
• The anesthetist should be immediately available for the first 15 minutes and thereafter contactable within 2 minutes 7

Multimodal Pain Management

• Combine regional anesthesia with scheduled acetaminophen (650 mg every 4-6 hours) 1
• Add NSAIDs/COX-2 inhibitors if not contraindicated 1
• Use opioids only as rescue medication 1

Common Pitfalls to Avoid

1. Inadequate visualization of needle tip during advancement
2. Intraneural injection (maintain visualization of local anesthetic spread)
3. Intravascular injection (aspirate before injection and use ultrasound to identify vessels)
4. Inappropriate padding that may increase pressure on nerves 7
5. Improper positioning leading to nerve stretch injuries
6. Exceeding maximum local anesthetic doses

By following these recommendations, clinicians can perform safe and effective brachial plexus blocks while minimizing complications and optimizing patient outcomes.