Advanced Airway

Aka: Advanced Airway, Difficult Airway Assessment

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II. Indications: Advanced Airway

  1. Airway Protection
    1. Unconscious patient (Glasgow Coma Scale <=8) or significantly altered
      1. Intracranial Hemorrhage
      2. Severe Closed Head Injury
      3. Status Epilepticus
      4. Drug Overdose with CNS depression
      5. Multiple Trauma, Head Injury, abnormal mental status or severe, refractory Agitation
    2. Other aspiration risk
      1. Bleeding into upper airway
      2. Vomiting
      3. Unable to speak or swallow
    3. Airway obstruction risk
      1. Anaphylaxis or Angioedema
      2. Neck Mass or Stridor
      3. Mouth or neck infection
        1. Epiglottitis
        2. Ludwig's Angina
      4. Severe Maxillofacial Trauma
        1. Inhalation burn or other Inhalation Injury (with cord edema)
        2. Neck Hematoma
        3. Tracheal injury
        4. Neck foreign body
  2. Ventilation and Oxygenation
    1. Respiratory arrest
    2. Respiratory Failure (e.g. Asthma, COPD, Pneumonia, Pulmonary Edema)
      1. Hypoventilation/Hypercarbia
        1. paCO2 >55 mmHg
      2. Arterial Hypoxemia refractory to oxygen
        1. paO2 <55 RA, <70 on 100% Face Mask
      3. Respiratory Acidosis
    3. Need for prolonged Ventilatory support
    4. Class III or IV Hemorrhage with poor perfusion
    5. Sepsis or other severe Metabolic Acidosis
    6. Severe Chest Injury (e.g. Flail Chest or Pulmonary Contusion)
    7. Neuromuscular disorder (e.g. Guillain Barre, Myasthenia Gravis)
      1. Vital Capacity <20 ml/kg predicts high risk of Respiratory Failure (indicates ICU monitoring)
      2. Intubation based on clinical findings (e.g. Tachypnea, discomfort)
  3. References
    1. Strayer (2017) EM:Rap 18(8): 9-10

III. Assessment (from the Difficult Airway Course)

  1. Anticipate difficult Direct Laryngoscopy (Mnemonic: LEMON)
    1. See LEMON Mnemonic
    2. Look externally (gestalt)
      1. Long or short Mandible
      2. High arched Palate
      3. Short neck
    3. Evaluate the 3-3-2 rule
      1. Significantly more or less than these values suggests more difficult airway management
      2. Measure each of 3 parameters using patient's own finger breadths
        1. Three fingers of mouth opening
        2. Three fingers between mentum and hyoid
        3. Two fingers between hyoid and Thyroid cartilage
      3. Images
        1. entAirwayLemon332.jpg
    4. Mallampati Score
      1. Score of 3-4 suggests higher risk
      2. Images
        1. entMallampatiAll.jpg
    5. Obstruction ("hot potato voice", inability to swallow secretions, Stridor)
      1. Severe Angioedema
      2. Supraglottic swelling
      3. Smoke Inhalation
    6. Neck mobility reduced (e.g. Cervical Spine Immobilization, Rheumatoid Arthritis)
  2. Anticipate difficult mask ventilation (Mnemonic: MOANS)
    1. See MOANS Mnemonic
    2. See ROMAN Mnemonic
    3. Mask seal (e.g. beard)
    4. Obstruction
    5. Older Age
    6. No teeth (replace dentures for Bag Valve Mask Ventilation)
    7. Stiff lungs requiring increased Ventilatory pressures (Asthma, COPD, ARDS, term pregnancy)
  3. Anticipate difficult Cricothyrotomy (Mnemonic: SHORT)
    1. See SHORT Mnemonic
    2. See SMART Mnemonic
    3. Surgery distorting the airway and tracheal access
    4. Hematoma, infection or mass in the path of the cricothryotomy
    5. Obesity or fixed flexion deformity of the neck
    6. Radiation to the neck
    7. Tumors involving the airway or in vicinity
  4. Anticipate difficult Extraglottic Device (Mnemonic: RODS)
    1. See RODS Mnemonic
    2. Restricted mouth opening
    3. Obstruction of the upper airway or Larynx
    4. Distorted or disrupted airway
    5. Stiff lungs requiring increased Ventilatory pressures (Asthma, COPD, ARDS, term pregnancy)
  5. References
    1. Reed (2005) Emerg Med J 22:99-102 [PubMed]
    2. Difficult Airway Course
      1. https://www.theairwaysite.com

IV. Precautions: Aspiration Risks (avoiding Vomiting during intubation is critical)

  1. Full Stomach (4-6 hours from last meal)
  2. Head Trauma (ICP increase, swallowed blood)
  3. Delayed Gastric Emptying
  4. Intestinal Obstruction
  5. Obesity
  6. Pregnancy

V. Protocol: Overview

  1. See Emergency Decision Cycle (OODA Loop, AAADA Model)
  2. Airway management always begins by opening the airway (e.g. position the head and neck)
    1. See Emergency Airway Management
  3. Advanced Airway is indicated (based on above indications)
    1. Endotracheal Intubation
    2. Laryngeal Mask Airway (LMA)
  4. Equipment: Laryngoscope
    1. Video Laryngoscopy is superior to Direct Laryngoscopy for successful intubation (by Odds Ratio >12)
      1. Sakles (2012) Ann Emerg Med 60(6):739-48
    2. However, Direct Laryngoscopy is most common means of rescuing Video Laryngoscopy (e.g. Glidescope) failure
      1. Best to maintain Direct Laryngoscopy skills to use as back-up procedure for device failure or malfunction
      2. Levitan and Brode in Majoewsky (2013) EM:Rap 13(1): 10
  5. Consider which of the 3 approaches is indicated
    1. Crash Airway (patient comatose or in cardiopulmonary arrest)
      1. Able to ventilate
        1. Attempt intubation
        2. If initial attempt fails, give Succinylcholine 2 mg/kg IV
        3. Make up to 3 additional attempts at intubation
      2. Unable to ventilate or oxygenate
        1. Go below to failed airway
    2. Difficult airway expected
      1. Call for help
      2. Unable to oxygenate or ventilate with Bag Valve Mask prior to any intervention attempt
        1. Consider BIPAP or CPAP for preoxygenation
        2. Prepare for Cricothyrotomy (see failed airway below)
          1. Consider Scott Weingart's CriCon double set-up approach
        3. Rapid Sequence Intubation with a single intubation attempt
          1. Consider Elastic Bougie placement, BIPAP, and then Endotracheal Tube placed over bougie
        4. Go below to failed airway
      3. Able to ventilate (with Bag Valve Mask)?
        1. Yes: May precede below with Rapid Sequence Intubation
        2. No: Anticipate inability to effectively Bag Valve Mask (PPV)
          1. Use awake patient measures
          2. Visualize airway under Local Anesthetic
            1. Direct Laryngoscopy or Video intubation
            2. Consider placing Elastic Bougie if cords visualized
          3. Fiberoptic intubation (e.g. flexible bronchoscopy)
            1. Light sedation and Local Anesthetic (e.g. cetacaine spray)
            2. Consider drying agent (e.g. glycopyrolate)
            3. Thread endoscope through ET Tube lumen and insert scope via nose or mouth
    3. Rapid Sequence Intubation (routine intubation allows time for premedication)
      1. See Rapid Sequence Intubation
  6. Failed airway options
    1. Failed intubation or cervical immobilization?
      1. Elastic Bougie guided intubation
      2. Tactile Orotracheal Intubation (Digital Intubation)
      3. Laryngeal Mask Airway (or other extraglottic airway) to temporize
      4. Nasotracheal Intubation (if no Maxillofacial Trauma, Basilar Skull Fracture)
      5. Intubating Laryngeal Mask Airway (intubating LMA)
    2. Cannot intubate, cannot oxygenate (and cannot ventilate): CICO
      1. Cricothyrotomy ("cut to air")

VI. Resources

  1. Airway Cam (Levitan)
    1. https://www.airwaycam.com/
  2. Airway World (Walls, requires free registration to view videos)
    1. https://amec.6connex.com/portal/airwayworld/login

VII. References

  1. Majoewsky (2012) EM: RAP-C3 2(5): 3-4
  2. Levitan (2013) Practical Airway Management Course, Baltimore
  3. Walls (2012) Emergency Airway Management, 3rd Ed, Lippincott, Philadelphia, p. 9-22, 82-93
  4. Fuchs and Yamamoto (2011) APLS, Jones and Bartlett, Burlington, p. 40-1

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