Cricothyroidotomy

• Cricothyroidotomy can provide a definitive airway via the cricothyroid membrane.
• Can be performed using open, percutaneous, or needle techniques (Needle cricothyroidotomy is not a definitive airway).
• Surgical cricothyroidotomy is the emergency front of neck access of choice.

DAS guidelines for management of unanticipated difficult intubation in adults

Decision Making

Indications

Main emergency indications are:

1. Airway obstruction (proximal to the subglottis)
2. Respiratory failure

Can also be used for bronchoscopy in emergencies.

Contraindications

Obesity or cervical trauma obscuring landmarks

Distal airway obstruction (e.g. tracheal stenosis)

Laryngeal cancer (unless in extreme emergencies)

Coagulopathy (except emergencies)

Special Considerations

Needle cricothyrotomy is preferred in children under 12 due to anatomy (cricothyroid membrane is smaller, the larynx is more funnel-shaped, rostral, and compliant and cricothyroidotomy may be more prone to causing subglottic stenosis)

Surgical Anatomy

Surface Landmarks

• Thyroid Cartilage: The midline prominence of the thyroid cartilage is the most identifiable landmark.
• Cricoid Cartilage: Situated inferior to the thyroid cartilage - this is the only complete cartilaginous ring in the airway.
• Cricothyroid Membrane: Found between the thyroid and cricoid cartilages - provides the access point for cricothyroidotomy.

Layers Traversed:

1. Skin
2. Subcutaneous Fat
3. Middle Cricothyroid Ligament of the Cricothyroid Membrane
4. Mucosa of the Subglottic Larynx

Cricothyroid Membrane Dimensions:

• Horizontal length: ~30 mm
• Vertical length: ~10 mm
• Cricothyroid muscles make the gap for passing a tube even narrower

Cricothyroid Arteries:

• Branches of the superior thyroid artery that cross the superior part of the cricothyroid membrane.
• Incisions should ideally avoid the superior margin of the cricoid cartilage to reduce the risk of bleeding.

Structures to Avoid:

• Vocal Cords: Located superior to the incision site; care must be taken to avoid injuring them.
• Cricoid Cartilage Lamina: Lies posteriorly; overextension or forceful dilation risks perforating the trachea posteriorly.
• Thyroid Isthmus: Usually crosses the 2nd-3rd tracheal rings but is not involved in this procedure unless aberrant anatomy (e.g., pyramidal lobe) is present.

Proximity to Other Structures:

• Trachea: Directly inferior to the cricothyroid membrane and continuous with the airway.
• Oesophagus: Posterior to the trachea; incorrect instrument placement may lead to oesophageal injury.
• Anterior Jugular Veins: Located laterally, off the midline, and usually not at risk unless deviated.

• Narrowest Point:
  • The tube passes through the cricoid ring, the narrowest part of the upper airway.

Practical Considerations

• Avoid making incisions too superior to prevent damage to the vocal cords.
• Use anatomical landmarks carefully, especially in obese or edematous patients, where palpation can be challenging.
• For emergency airway access, a transverse incision at the cricothyroid membrane, angled slightly cephalad, is ideal to avoid posterior wall injury.

By understanding and adhering to these anatomical guidelines, surgeons can effectively perform cricothyroidotomy while minimizing risks of complications.

Pre-operative Planning

Evaluate the level of obstruction and palpability of landmarks

If a difficult airway is anticipated - can mark the landmarks before intubation is attempted (see below)

Consent

Risks

Bleeding

Tracheal wall perforation

Subglottic stenosis

Infection

Alternatives

Needle cricothyrotomy

Tracheostomy

Other steps in the DAS guidelines

Surgical Instruments

Equipment:

• Scalpel blade (e.g. size 10)
• Artery forceps
• Bougie
• Size 6-0 ETT (or tracheostomy tube)

Anaesthesia, Positioning, and Draping

Position supine with the neck exposed and extended (if possible)

Can administer local anaesthesia if time permits

Skin Marking

Identify and mark:

1. Thyroid cartilage
2. Cricothyroid membrane
3. Cricoid cartilage

Edit of original from Wikimedia Commons. Top black line = thyroid notch, middle black line = cricoid cartilage, bottom black line = sternal notch. Red line = cricothyroid membrane (location of cricothyroidotomy). Green line = standard location for tracheostomy incision.

Surgical Steps

Difficult Airway Society Training Video

1. 1. Locate the Larynx:
      • Use your non-dominant hand to perform a laryngeal handshake, palpating the thyroid cartilage, cricoid cartilage, and cricothyroid membrane.
      • Place your index finger directly on the cricothyroid membrane to confirm its location.
   2. Prepare the Larynx:
      • Stabilize the larynx with your non-dominant hand. Use your thumb and fingers to stretch the skin taut over the cricothyroid membrane.
      • Hold the scalpel in your dominant hand.
   3. Make the Initial Incision:
      • With the cutting edge of the blade facing toward you, make a transverse stab incision through the skin and cricothyroid membrane.
      • You will feel a distinct pop as the scalpel penetrates the trachea.
   4. Reposition the Scalpel:
      • Keeping the scalpel perpendicular to the skin, rotate it 90 degrees so the sharp edge points toward the feet.
      • Switch hands to hold the scalpel with your non-dominant hand.
   5. Maintain the Incision:
      • Apply gentle traction, pulling the scalpel toward you to create a triangular incision. Ensure the scalpel handle remains upright at 90 degrees to the skin.
   6. Introduce the Bougie:
      • Hold the bougie in your dominant hand, keeping it parallel to the floor and perpendicular to the tracheal plane.
      • Slide the angled tip of the bougie down the scalpel blade, maintaining contact until it enters the trachea.
      • Rotate the bougie to align it with the trachea and advance it gently 10–15 cm into the airway.
   7. Place the Tracheal Tube:
      • Remove the scalpel while keeping the bougie in place.
      • Advance a size 6 tracheal tube over the bougie and into the trachea, rotating the tube gently during insertion.
      • Avoid over-advancing the tube.
   8. Secure the Airway:
      • Remove the bougie.
      • Attach the ventilation circuit and deliver oxygen.
      • Inflate the cuff to secure the airway.
   9. Verify Placement:
      • Confirm ventilation using capnography.
      • Recheck the tube’s depth to ensure proper placement.
   10. Finalize:
       • Secure the tracheal tube with appropriate fixation.
       • Monitor the patient for adequate ventilation and oxygenation.

Post-operative Care

Monitor for pulmonary oedema and respiratory arrest.

Ensure humidification to prevent mucosal damage.

Regularly suction secretions aseptically.

Check cuff pressures and secure the tube to prevent accidental decannulation.

Follow-up

Monitor for long-term complications, including stenosis or dysphonia.

Perform regular tracheostomy care.

Complications

Immediate: Bleeding, false tract formation, pneumothorax.

Long-term: Subglottic stenosis, persistent stoma, tracheoesophageal fistula.