Extraglottic Device

Aka: Extraglottic Device, Supraglottic Device, Supraglottic Airway, Laryngeal Mask, Laryngeal Mask Airway, LMA, Esophageal Obturator Airway, Esophageal Tracheal Combitube, King Supraglottic Airway, I-Gel, Pre-Hospital Extraglottic Airway Management, RODS Mnemonic

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II. Preparations: Extraglottic Device - Laryngeal Mask Airway (LMA, I-Gel)

  1. Preferred Extraglottic Device
  2. Used as bridge to definitive airway (especially as back-up for failed intubation, if no airway obstruction)
  3. LMA may be used as conduit to carry fiberoptic scope
  4. Some LMAs (intubating LMA, I-Gel) may be used as conduit to intubate
    1. Use a bronchoscope with a Preloaded ET Tube
      1. LMAs can accept an ET Tube diameter 3 sizes up from LMA (e.g. #4 LMA accepts a 7.0 ET Tube or smaller)
      2. Specific Intubating LMAs may be used with bronchoscope (but have a 10% fail rate)
    2. Avoid removing intubating LMA initially after intubating (risk of dislodging ET Tube)
    3. LMA may be removed later under controlled conditions
  5. Does not secure upper airway (risk of aspiration)
    1. LMAs should be used with orogastric suction (some have specific ports for suction catheter)
    2. I-Gel, for example, has a port that accepts a 12 french NG tube (small)
  6. Insertion Technique
    1. Select proper LMA size (see below, #4 is most common for adults, #3 for small female, #5 for a large male)
    2. Test the LMA cuff by inflating, and then deflate the LMA cuff
    3. Lubricate the closed, convex, posterior LMA surface (Palate side of the device)
    4. Place your index and middle finger into the anterior or airway side of the LMA
    5. Insert the LMA, with the open, concave side facing the inner mouth
      1. Lubricated, posterior side should be against the Palate
    6. Allow the LMA to glide along the Palate and settle into the airway
    7. Inflate the LMA cuff when seated in the airway

III. Preparations: Extraglottic Device - Supraglottic Airways (or King LT) or Esophageal Tracheal Combitube (ETC)

  1. Used primarily by prehospital personnel
  2. Balloon inflation (and deflation) on device requires practice

IV. Technique: Anticipate difficult Extraglottic Device (Mnemonic: RODS)

  1. Restricted mouth opening
  2. Obstruction of the upper airway or Larynx
  3. Distorted or disrupted airway
  4. Stiff lungs requiring increased Ventilatory pressures (Asthma, COPD, ARDS, term pregnancy)

V. Precautions

  1. Vomiting
    1. Consider pre-treatment with Antiemetics (e.g. Zofran)
    2. Extraglottic Devices including LMA do not protect the airway
      1. May increase risk of aspiration (by deflecting vomit into airway)
  2. High pressure, non-compliant lungs (Asthma or COPD)
    1. Extraglottic Devices including the LMA cannot generate airway pressures above 25 mmHg
  3. Over-inflation of balloon (especially LMA)
    1. Avoid over-inflating with LMA (un-seats the LMA, and pushes the LMA up and out of airway)
    2. LMA #3 (small female): Inflate 10cc air
    3. LMA #4 (large female, small male): Inflate 15cc air
    4. LMA #5 (large male): Inflate 20cc air

VI. Approach: Pre-Hospital Extraglottic Airway

  1. Cardiac Arrest patients often arrive at Emergency Department with extraglottic airways placed in field
  2. Evaluate extraglottic airway placement and ventilation on arrival
    1. Continuous waveform Capnography
    2. Bilateral lung air movement
    3. Consider glidescope or Laryngoscope confirmation of airway placement
  3. Confirmed extraglottic airway proper placement should be left in place initially
    1. Offers adequate initial airway management and allows for complete patient assessment
    2. Gastric decompression may be performed with Orogastric Tube passed through side port
    3. Sufficient airway control to allow for imaging and other testing
    4. Extraglottic airways may be connected to Ventilator (typically pressure control ventilation)
  4. Removal of extraglottic airway on arrival and prematurely may result in patient decompensation
    1. Confirmed extraglottic airway proper placement is unlikely to be cause of Hypoxia
    2. Plan for Endotracheal Tube placement when patient stabilized
  5. Endotracheal Tube Exchange for Extraglottic Device
    1. King Airway with Difficult airway anticipated
      1. Leave King Airway in Esophagus but deflate the balloons
      2. Place Laryngoscope beside the King Airway and sweep it to the side
      3. Intubate the airway while the King Airway is in the Esophagus
      4. Dodd (2017) J Emerg Med 52(4):403-8 +PMID:27876327 [PubMed]
    2. I-Gel Airway or Intubating LMA with Difficult airway anticipated
      1. Perform Endoscopic Intubation while the Extraglottic Device is still being ventilated
  6. References
    1. Swaminathan and Braude in Herbert (2020) EM:Rap 14-5
    2. Braude (2019) Ann Emerg Med 74(3): 415-22 +PMID:31060744 [PubMed]

VII. Efficacy

  1. Prehospital extraglottic airways (LMA, I-Gel) offer at least equal if not better survival benefit in out-of-hospital Cardiac Arrest
    1. Benger (2018) JAMA 320(8):779-91 +PMID:30167701 [PubMed]
    2. Wang (2018) JAMA 320(8):769-78 +PMID:30167699 [PubMed]

VIII. Resources

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

IX. References

  1. Levitan (2013) Practical Airway Management Course, Baltimore
  2. Walls (2012) Difficult Airway Course, Chicago

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