What is the recommended anesthetic protocol for an intranasal (intra-nasal) block?

Recommended Anesthetic Protocol for Intranasal Block

For intranasal blocks, the recommended protocol is lidocaine 2-5% combined with phenylephrine 0.5% as a vasoconstrictor, with a maximum total lidocaine dose not exceeding 9 mg/kg lean body weight. 1

Medication Selection and Dosing

Local Anesthetic Agent

• First choice: Lidocaine (2-5%)
  • Preferred due to favorable cardiovascular and systemic toxicity risk profile 1
  • Maximum dose: 9 mg/kg lean body weight (not a target but a maximum) 1
  • Higher concentrations may provide faster onset but not necessarily better efficacy 1

Vasoconstrictor

• First choice: Phenylephrine 0.5% combined with lidocaine 1, 2
  • Reduces incidence of epistaxis 1
  • More appropriate than cocaine due to safety profile 1
• Alternative: Xylometazoline with lidocaine 2% gel 2

Combination Products

• Co-phenylcaine (2.5 ml lidocaine 5%/phenylephrine 0.5%) is effective 1
• Tetracaine 2% with oxymetazoline 0.05% is an effective alternative 2

Administration Techniques

Topicalization Methods

• Direct application: Apply 2-5% lidocaine to the nasal passages 2
• Mucosal atomization device (MAD): Delivers fine spray of local anesthetic 1
• Gel application: Lidocaine 2% gel can provide good coverage and patient acceptance 2

Timing Considerations

• Allow adequate time for onset of action:
  • Lidocaine onset: approximately 5 minutes 1
  • Optimal anesthetic effect: 25-30 minutes after application 3
  • Peak effect: 35-40 minutes after application 3

Safety Considerations

Avoiding Toxicity

• Monitor for signs of local anesthetic toxicity (lightheadedness, perioral numbness, tinnitus) 1
• Consider total dose of all local anesthetics administered regardless of route 1
• Avoid occlusive dressings which can triple serum lidocaine levels 4
• Have lipid emulsion available in case of local anesthetic toxicity 1

Special Precautions

1. Avoid cocaine due to:

   • Toxic cardiovascular complications 1
   • No superior analgesic efficacy compared to co-phenylcaine 1

2. Absorption variability:

   • Significant interindividual variation in lidocaine absorption 4, 5
   • OTC preparations may lead to higher serum levels than prescription formulations 5

Procedural Steps

1. Pre-procedure:

   • Consider antisialogogue (glycopyrronium bromide 0.2-0.4 mg) 30-60 minutes before procedure 1
   • Apply topical nasal vasoconstrictor first 1

2. Topicalization:

   • Apply lidocaine with phenylephrine to nasal passages
   • Allow adequate time for onset (minimum 5 minutes, optimal 25-30 minutes) 3

3. Testing adequacy:

   • Test adequacy of topicalization in an atraumatic manner before instrumentation 1
   • Use a soft suction catheter or Yankauer sucker to assess anesthetic effect 1

4. Supplemental oxygenation:

   • Provide supplemental oxygen throughout the procedure 1
   • High-flow nasal oxygen is preferred if available 1

By following this protocol, you can achieve effective anesthesia for intranasal procedures while minimizing the risk of complications and ensuring patient comfort.