What is the recommended protocol for a stellate ganglion block?

Stellate Ganglion Block Protocol

The recommended protocol for stellate ganglion block (SGB) involves ultrasound-guided injection of 6-8 mL of local anesthetic (typically bupivacaine 0.25-0.5%) at the C6 level with appropriate safety precautions including intravenous access, monitoring, and resuscitation equipment readily available. 1, 2, 3

Preparation and Safety Measures

Pre-procedure Requirements

• Obtain informed consent after discussing risks, benefits, and alternatives
• Place intravenous line before procedure (recommended by 72% of departments) 2
• ECG monitoring during the procedure (recommended by 28% of departments) 2
• Ensure presence of an assistant during the procedure (recommended by 73% of departments) 2
• Have resuscitation equipment immediately available including:
  • Oxygen and ventilation devices
  • Anticonvulsant medications
  • Intubation equipment 2

Contraindications

• Coagulopathy or anticoagulant therapy
• Local infection at injection site
• Allergy to local anesthetics
• Severe cardiac conduction abnormalities

Technique

Patient Positioning

• Supine position with neck slightly extended
• Head turned away from the side to be blocked

Ultrasound-Guided Approach (Preferred)

1. Use ultrasound guidance to identify the C6 level (or C7 as an alternative) 3

2. Identify key landmarks:

   • Carotid artery
   • Longus colli muscle
   • Prevertebral fascia
   • Transverse process of C6 (Chassaignac's tubercle)

3. Medication preparation:

   • Bupivacaine 0.25-0.5% (preferred by 82% of departments) 2, 3
   • Volume: 6-8 mL provides optimal efficacy (4 mL may be insufficient) 4
   • Optional: Consider administering a test dose of 0.5-2 mL before full injection (used by 53% of departments) 2

4. Needle insertion:

   • Use a 22-25G needle
   • Insert needle in an anteroposterior direction
   • Advance to the prevertebral fascia anterior to the longus colli muscle
   • Perform careful aspiration before injection to avoid intravascular administration

5. Injection:

   • Inject slowly after negative aspiration
   • Observe for spread of local anesthetic anterior to longus colli muscle

Alternative Landmark-Based Approach

• Identify Chassaignac's tubercle (C6 transverse process)
• Insert needle perpendicular to skin until contact with tubercle
• Withdraw 1-2 mm and inject after negative aspiration

Assessment of Block Efficacy

Signs of Successful Block

• Horner's syndrome (miosis, ptosis, enophthalmos, and conjunctival reddening)
• Increased skin temperature (≥34°C or increase of ≥1.5°C from baseline)
• Increased skin blood flow (≥50% increase)
• Abolished skin resistance response
• Increased skin resistance level (≥13%) 3

Monitoring Parameters

• Skin temperature of face and hand (bilateral comparison)
• Development of Horner's syndrome (typically within 5-10 minutes)
• Hemodynamic parameters
• Respiratory status

Potential Complications and Management

Common Side Effects

• Hoarseness (recurrent laryngeal nerve block)
• Nasal congestion
• Facial warmth and flushing
• Temporary dysphagia

Serious Complications (Rare: 1.7 per 1000 blocks) 2

• CNS complications (seizures from intravascular injection)
• Subarachnoid or epidural spread
• Pneumothorax
• Allergic reactions
• Vertebral artery injection
• Hematoma formation

Management of Complications

• For local anesthetic systemic toxicity: Stop injection, administer oxygen, manage seizures, consider lipid emulsion
• For respiratory compromise: Maintain airway, provide ventilatory support
• For pneumothorax: Chest tube if significant

Special Considerations

• C7 level injection may provide better efficacy than C6 for sympathetic blockade 3
• Higher concentration of local anesthetic appears more effective than larger volume 3
• For patients with cardiac conditions, careful monitoring is essential as SGB can affect cardiac sympathetic innervation 5
• Avoid SGB in patients with COVID-19 or suspected infection due to potential risk of viral transmission 1

Post-Procedure Care

• Monitor vital signs for at least 30 minutes post-procedure
• Assess for development of Horner's syndrome and temperature changes
• Provide patient education regarding temporary side effects (ptosis, nasal congestion)
• Advise patients to avoid driving immediately after the procedure due to potential visual changes

SGB is an effective intervention for various pain conditions when performed correctly with appropriate safety precautions. The key to success is proper technique, adequate volume of local anesthetic, and careful patient monitoring.