- Need for positive pressure ventilation (PPV)
- LMA better than endotracheal for paramedics, especially in pediatric patients
- Spontaneous respirations
- Gag reflex
- Significant facial trauma
Difficult Supraglottic Device (RODS)
- Restricted motnh opening
- Distorted airway
- Stiff lungs or neck (c-spine)
- Supraglottic Airway (SGA) device (many options exist, see below)
- Appropriate sedation/paralytic agents, if indicated
|Mask Size||Weight (kg)||Age (yr)||LMA Length (cm)||LMA Cuff Vol (mL)||Largest ETT^ (mm)|
^Largest ETT that can pass thorough "Intubating LMA" (ILMA)
|igel size||patient size||weight (kg)|
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.
- Paralyze (if indicated)
- Place supraglottic airway device - possible techniques include:
- 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)
- Laryngeal nerve injury
- Hypoglossal nerve injury
- Pharyngeal edema
- There are 2 generations of supraglottic airway devices
- 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.
- Higher failure rate with obese patients, inappropriate patient position (e.g. trendelenberg), and placement by inexperienced provider
- 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
- 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)
- Zhu X-Y, Lin B-C, Zhang Q-S, Ye H-M, Yu R-J. A prospective evaluation of the efficacy of the laryngeal mask airway during neonatal resuscitation. Resuscitation. 2011;82(11):1405–1409. doi:10.1016/j.resuscitation.2011.06.010
- Calkins MD, Robinson TD. Combat trauma airway management: endotracheal intubation versus laryngeal mask airway versus combitube use by Navy SEAL and Reconnaissance combat corpsmen. J Trauma. 1999;46(5):927–932
- Tarascon Adult Emergency Pocketbook
- 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.
- Timmermann, A. Supraglottic airways in difficult airway management: successes, failures, use and misuse. Anaesthesia, 2011, 66(Suppl. 2), pages 45–56.