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Supraglottic airway
From WikEM
Contents
Indications
- Need for positive pressure ventilation (PPV)
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
- ↑ 1.0 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
- ↑ 2.0 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)
- ↑ Tarascon Adult Emergency Pocketbook
- ↑ 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.
- ↑ Timmermann, A. Supraglottic airways in difficult airway management: successes, failures, use and misuse. Anaesthesia, 2011, 66(Suppl. 2), pages 45–56.
