Supraglottic airway

Indications

  • Need for positive pressure ventilation (PPV)
    • Can be used both as primary and rescue airway (if BVM or intubation fail)[1]
    • Can also be used as a conduit/guide for elective or rescue fiberoptic intubation[2]

Contraindications

Absolute

  • Spontaneous respirations
  • Gag reflex

Relative

  • Significant facial trauma

Difficult Supraglottic Device (RODS)

  • Restricted motnh opening
  • Obstruction
  • Distorted airway
  • Stiff lungs or neck (c-spine)

Equipment Needed

  • Supraglottic Airway (SGA) device (many options exist, see below)
  • Appropriate sedation/paralytic agents, if indicated

LMA Sizes[3]

Mask Size Weight (kg) Age (yr) LMA Length (cm) LMA Cuff Vol (mL) Largest ETT^ (mm)
1 <5 <0.5 10 4 3.5
1.5 5-10 <1 10 5-7 4
2 6.5-20 1-5 11.5 7-10 4.5
2.5 20-30 5-10 12.5 14 5
3 30-60 10-15 19 15-20 6
4 60-80 >15 19 25-30 6.5
5 >80 >15 19 30-40 7

^Largest ETT that can pass thorough "Intubating LMA" (ILMA)

iGel Sizes

igel size patient size weight (kg)
1 neonate 2-5
1.5 infant 5-12
2 smal pediatric 10-25
2.5 large pediatric 25-35
3 small adult 30-60
4 medium adult 50-90
5 large adult 90+

Procedure

Due to variety of devices and placement techniques, impossible to give exact universal procedure

  • Prepare patient (appropriate positioning, preoxygenate, pretreatment if indicated)
    • Topical anesthetic to posterior oropharyngeal mucosa may be beneficial in awake Intubation/LMA placement.
  • Induction
  • Paralyze (if indicated)
  • Place supraglottic airway device - possible techniques include[4]:
    • Use thumb/index finger to guide SGA along midline of hard palate (cuff deflated or partially inflated, if possible) - advance until seated
    • Insert SGA with cuff facing hard palate, then rotate 180 degrees while advancing (similar to OPA insertion)
    • Insert laterally 45 degrees against tongue, advance and rotate to midline
  • Inflate cuff (if applicable)
  • Confirm placement (CXR, etCO2, lung sounds, listen for oropharyngeal air leak)

Complications[1]

  • Bronchospasm
  • Hoarseness
  • Laryngeal nerve injury
  • Hypoglossal nerve injury
  • Pharyngeal edema
  • Dysphagia

Special Considerations

  • There are 2 generations of supraglottic airway devices[5][2]
    • 1st Gen = classic LMA, other standard LMAs
    • 2nd Gen = iGel, LMA Supreme, Pro-Seal LMA (PLMA)
  • Second generation devices achieve improved esophageal and pharyngeal seal (causes ↑ oropharyngeal leak pressure), incorporate a "drain tube" that allows access to the esophagus and stomach, and usually have an incorporated bite block.
  • Oropharyngeal leak pressure = the applied pressure at which the seal between the device and the larynx begins to leak.
    • Peak inspiratory pressure needs to be less than the oropharyngeal leak pressure for effective ventilation and to prevent gastric insufflation.[4]
  • Higher failure rate with obese patients, inappropriate patient position (e.g. trendelenberg), and placement by inexperienced provider[2]

See Also

References

  1. 1.0 1.1 Apfelbaum JL, et al.; American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013 Feb;118(2):251-70
  2. 2.0 2.1 2.2 Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Cook TM, Woodall N, Frerk C; Fourth National Audit Project. Br J Anaesth. 2011 May;106(5)
  3. Tarascon Adult Emergency Pocketbook
  4. 4.0 4.1 Patel B., Bingham R. Laryngeal mask airway and other supraglottic airway devices in paediatric practice. Contin Educ Anaesth Crit Care Pain (2009) 9 (1): 6-9.
  5. Timmermann, A. Supraglottic airways in difficult airway management: successes, failures, use and misuse. Anaesthesia, 2011, 66(Suppl. 2), pages 45–56.