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Equipment for Emergency Cricothyrotomy: Types, Indications, and Limitations

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ANATOMY OF THE CRICOTHYROID MEMBRANE (CTM)

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DEFINITION AND TERMINOLOGY

• Barash Clinical Anesthesia, 9e - Cricothyrotomy, p. 2405
• Miller's Anesthesia, 10e - p. 5958

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INDICATIONS

Primary Indication - CICO (Cannot Intubate, Cannot Oxygenate)

1. Conventional orotracheal/nasotracheal intubation has failed
2. Oxygenation cannot be maintained (SpO₂ cannot be maintained >90% between intubation attempts or after three attempts)
3. Bag-valve-mask ventilation has failed

Specific Indications (Roberts & Hedges; Tintinalli's; Rosen's):

"If standard intubation seems unlikely to succeed, it is not always necessary to attempt it prior to establishing a surgical airway." - Tintinalli's Emergency Medicine

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CONTRAINDICATIONS

Absolute:

• Age < 5-12 years (depending on source - the cricoid is the narrowest part in children; surgical cricothyrotomy is contraindicated; needle cricothyrotomy with TTJV is preferred)
• Laryngeal fracture
• Tracheal transection or obstruction below the CTM
• Complete airway obstruction (for jet ventilation - expiration is blocked)
• Laryngeal neoplasm or subglottic stenosis

Relative:

• Coagulopathy
• Distorted or unidentifiable neck anatomy (obesity, haematoma, prior surgery)
• Local infection at puncture site
• Operator unfamiliarity

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TYPES OF EMERGENCY CRICOTHYROTOMY & EQUIPMENT

┌─────────────────────────────────────────────────────────────┐
│              EMERGENCY CRICOTHYROTOMY                       │
│                         │                                   │
│         ┌───────────────┼───────────────┐                   │
│         ▼               ▼               ▼                   │
│   NEEDLE/CANNULA   SURGICAL (Open)  PERCUTANEOUS            │
│  CRICOTHYROTOMY    CRICOTHYROTOMY    DILATIONAL              │
│   + PTLV/TTJV                      (Seldinger)              │
└─────────────────────────────────────────────────────────────┘

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TYPE 1: NEEDLE CRICOTHYROTOMY (with Percutaneous Translaryngeal Ventilation / TTJV)

Equipment Required:

"Do not try to use standard oxygen tubing, three-way stopcocks, or bag-valve devices or attach to wall outlets turned to highest liter flow." - Tintinalli's, p. 240

Technique Summary (Tintinalli's):

1. Extend neck; identify CTM
2. Stabilize thyroid cartilage with non-dominant hand
3. Attach 3 mL syringe to catheter; insert at 45° caudally through CTM
4. Aspirate air to confirm tracheal entry
5. Advance catheter to hub; remove needle
6. Connect jet ventilator; I:E ratio 1:4; max 1 second inspiration
7. Monitor chest rise; auscultate bilateral breath sounds

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TYPE 2: SURGICAL CRICOTHYROTOMY (Open / Standard Technique)

Equipment Required (Tintinalli's - Table 30-3; Roberts & Hedges; Miller's Box 40.4):

• Traditional 5-step technique: Incise skin → identify CTM → stab/incise CTM horizontally → dilate with Trousseau dilator → insert tube
• Rapid Four-Step Technique (RFST / Brantigan-Grow): Palpate → horizontal stab incision through skin AND CTM → caudal traction with tracheal hook → insert tube (omits dilator; faster but slightly higher complication rate in some studies)
• Bair Claw modification: Replaces single hook with double-hook device; reduces cricoid ring fractures; operator positioned at head of bed

Surgical Cricothyrotomy Technique (Miller's Box 40.4):

1. Stand on patient's left (if right-handed)
2. Stabilize larynx with left hand
3. Left index finger identifies CTM (if not palpable, 8-10 cm vertical midline incision + blunt dissection)
4. Transverse stab incision through skin and CTM with right hand, blade edge toward you
5. Keep scalpel perpendicular; rotate 90° so cutting edge points caudally
6. Swap hands; left hand maintains gentle lateral traction on scalpel (keeping handle vertical)
7. Insert bougie caudally beside scalpel blade
8. Remove scalpel; railroad 6 mm cuffed ETT over bougie; inflate cuff; ventilate
9. Confirm placement (capnography, bilateral breath sounds)

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TYPE 3: PERCUTANEOUS DILATIONAL CRICOTHYROTOMY (Seldinger Technique)

Equipment in Melker Kit (Roberts & Hedges):

Technique:

1. Identify CTM; insert 18G needle with syringe at 45° caudally; aspirate air/saline bubbles confirm entry
2. Advance TFE catheter; remove needle; insert guidewire through catheter; remove catheter
3. Small skin incision at guidewire entry
4. Thread dilator + Melker catheter together over wire → advance flush with skin → remove guidewire and dilator
5. Inflate cuff; confirm placement; ventilate

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COMPARISON OF TECHNIQUES

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LIMITATIONS OF EACH TECHNIQUE

Needle Cricothyrotomy Limitations:

• Not a definitive airway - bridge only; CO₂ accumulates rapidly (safe for ~30-45 minutes only)
• Kinking of catheter - standard IV catheters kink easily; dedicated kink-resistant catheters (Cook, Ravussin) are mandatory
• High-pressure source mandatory - BVM and standard wall O₂ flowmeters are inadequate; if proper jet ventilator is unavailable, ventilation is ineffective
• Barotrauma risk - pneumothorax, massive subcutaneous emphysema, mediastinal emphysema if catheter misplaced or ventilation excessive
• Requires patent upper airway for exhalation - passive exhalation must occur via glottis; complete upper airway obstruction is the only absolute contraindication
• Small catheter lumen - limits gas flow; 16G or larger preferred (13G commercial catheters ideal)
• Catheter displacement - requires constant manual stabilization; easily dislodged

Surgical Cricothyrotomy Limitations:

• Contraindicated in children <5-12 years - funnel-shaped compliant pediatric larynx; cricoid is narrowest point; thyroid isthmus overlies CTM
• Subglottic stenosis - historically feared; now known to be infrequent; risk increased with prolonged cannulation, old age, diabetes, concurrent laryngeal pathology
• Requires identifiable CTM - obesity, haematoma, prior surgery may obscure landmarks
• Not a permanent airway - must be converted to formal tracheostomy (ideally within 72 hours) or removed
• Vocal cord/laryngeal injury - if blade passes too deeply or cephalad
• Bleeding - thyroidea ima artery (midline branch of aorta), cricothyroid vessels laterally
• Tube malposition - mainstem bronchial intubation, tube impinging on vocal cords
• Cricoid ring fracture - reported with single-hook RFST; reduced with Bair Claw

Percutaneous Seldinger Limitations:

• Requires easily identifiable CTM - anatomical distortion makes needle localisation difficult (unlike surgical technique where skin incision first exposes anatomy)
• Guidewire complications - wire may pass in wrong direction or kink
• Slower than surgical technique - multiple steps; less suited to extreme emergencies
• Less reliable in soiled/bloody fields - guidewire placement less reliable with active hemorrhage
• Smaller airway catheter - compared to standard ETT, may limit suctioning

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COMPLICATIONS

Acute Complications (More Common):

• Tube malposition / failed placement
• Hemorrhage (thyroidea ima, cricothyroid vessels)
• Mainstem bronchial intubation
• Laryngotracheal injury
• Subcutaneous emphysema
• Tension pneumothorax (rare)

Acute Complications (Less Common):

• Esophageal puncture
• Aspiration
• Retrograde pharyngeal intubation

Late Complications:

• Subglottic / glottic stenosis (infrequent; risk factors: prolonged cannulation, DM, old age, laryngeal pathology)
• Voice change (most common reported long-term complaint)
• Difficulty swallowing
• Wound infection
• Tracheomalacia (especially with TTJV)
• Vocal cord changes

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FAILED AIRWAY ALGORITHM - CICO PATHWAY

FAILED INTUBATION
        │
        ▼
Can you oxygenate with BVM / SGA?
        │
   YES  │   NO (CICO)
        │      │
        │      ▼
        │  ┌─────────────────────────────────────┐
        │  │     FRONT OF NECK ACCESS (FONA)     │
        │  │                                     │
        │  │  Age ≥ 10-12 years?                 │
        │  │     │              │                │
        │  │    YES             NO               │
        │  │     │              │                │
        │  │     ▼              ▼                │
        │  │  SURGICAL      NEEDLE               │
        │  │  CRICOTHYROTOMY  CRICOTHYROTOMY      │
        │  │  (preferred)   + TTJV               │
        │  │     │          (children)           │
        │  │     ▼                               │
        │  │  6 mm cuffed ETT via                │
        │  │  bougie / scalpel-bougie            │
        │  │  technique                          │
        │  │     │                               │
        │  │     ▼                               │
        │  │  Stabilize → Plan for tracheostomy  │
        │  └─────────────────────────────────────┘
        │
        ▼
  Awaken patient if possible /
  continue with definitive plan

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POST-PROCEDURE CONSIDERATIONS

• Cricothyrotomy is NOT a permanent airway - conversion to formal tracheostomy should be planned
• Confirm placement with capnography and bilateral auscultation
• Secure tube with tapes/ties/sutures
• Plan for ICU admission
• Decannulate as soon as clinically feasible to reduce subglottic stenosis risk

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KEY POINTS SUMMARY

1. CTM is ~9 mm × 30 mm, subcutaneous, midline - the safest anterior neck access point
2. Three techniques: Needle (TTJV), Surgical (Open), Percutaneous Seldinger
3. Primary indication: CICO (SpO₂ <90%, failed BVM, failed ≥3 intubation attempts)
4. Surgical cricothyrotomy is contraindicated below age 5-12 years; needle technique is preferred in children
5. Dedicated kink-resistant catheters and high-pressure (35-50 psi) O₂ are mandatory for effective TTJV
6. Surgical technique has highest success rate (90-100%); cannula technique ~50% by anaesthesiologists
7. Not a permanent airway - convert to tracheostomy after stabilisation
8. The feared complication of subglottic stenosis is now known to be infrequent

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• Barash Clinical Anesthesia, 9e - pp. 2405-2411
• Miller's Anesthesia, 10e - Box 40.4, pp. 5958-5962
• Tintinalli's Emergency Medicine, 9e - Chapter 30, Tables 30-3, 30-5
• Roberts and Hedges' Clinical Procedures in Emergency Medicine, 7e - Chapter 6, Boxes 6.2, 6.3
• Morgan & Mikhail's Clinical Anesthesiology, 7e - Chapter 19, Chapter 55, Figure 55-6
• Washington Manual of Medical Therapeutics - pp. 3514-3568
• Rosen's Emergency Medicine, 9e - Chapter 1 (Failed Airway Algorithm)