Awake Intubation Techniques

Overview

• Importance of awake intubation in emergency situations (3:00 a.m. scenario).
• Goal: Achieve complete airway anesthesia rapidly (under 5 minutes).
• Challenge: Awkward awake intubations often lead to patient discomfort (gagging, coughing, multiple attempts).

Anatomy of the Airway

• Rich Innervation: The airway is hard to anesthetize due to its rich nerve supply.
• Key Nerves:
  • Glossopharyngeal Nerve: Innervates tongue, pharynx, and posterior third of the tongue; responsible for gag reflex.
  • Superior Laryngeal Nerve: A branch of the vagus nerve; innervates larynx inlet and upper vocal cords.
  • Recurrent Laryngeal Nerve: Another branch of vagus; innervates the airway below the cords.
  • Maxillary Branch of Trigeminal: Innervates palate (less clinically relevant).

Anesthesia Technique Overview

• Complete Airway Anesthesia: Essential for successful awake intubation.
• Recommended method: Block all three key nerves.
• Equipment Needed:
  • 22-gauge spinal needle
  • 4 x 3 mL syringes
  • 10 mL syringe
  • 25 or 23 gauge needles
  • 20 mL of 2% lidocaine
  • Tongue depressor
  • Syringe for skin local anesthesia
  • Gauze and gloves.

Nerve Blocking Techniques

1. Glossopharyngeal Nerve Block

• Technique:
  • Use 3 mL of 2% lidocaine administered submucosally near posterior tonsillar pillar.
  • Retract tongue using depressor or laryngoscope.
  • Ideal injection site: Caudal aspect of the posterior tonsil pillar.
• Injection Steps:
  • Advance needle through mucosa, aspirate, inject.
  • Repeat on the other side.
• Aspirate Tips:
  • Blood indicates too lateral, air indicates through and through.

2. Superior Laryngeal Nerve Block

• Ultrasound Guidance:
  • Position probe on thyrohyoid membrane.
  • Visualize hyoid bone and thyroid cartilage.
• Technique:
  • Insert needle through the membrane, aspirate, and inject 3 mL of local.
  • Ensure to avoid the superior thyroid artery.

3. Recurrent Laryngeal Nerve Block

• Technique:
  • Approach via cricothyroid membrane.
  • Aspirate air to confirm placement in trachea.
  • Inject 4 mL of 2% lidocaine quickly.
  • Coughing during injection helps distribute anesthetic.

Additional Tips

• Tongue Retraction: Can provoke gagging; use extra lidocaine if necessary.
• Nasal Intubation: Usually doesn't require nasal cavity anesthesia.
• Other Methods: Nebulizers, gargles, sprays are less effective and take more time.

Safety and Efficacy

• Patient Cooperation: Critical for success; avoid sedation overuse to prevent airway emergencies.
• Data Support: Blocks often outperform topical methods in efficacy and safety.
• Dosage Consideration: Safe limit for lidocaine is 5 mg/kg; aim for quick, effective anesthesia.
• Overall Goal: Complete nerve blocks in under 5 minutes, ensuring readiness for intubation.