Overview
This lecture covers the laryngeal mask airway (LMA): its parts, indications, contraindications, insertion steps, advantages, disadvantages, and post-placement care as used in emergency settings.
LMA Anatomy and Function
- The LMA is a supraglottic airway device used mainly in patients with reduced consciousness, such as cardiac arrest.
- Key airway structures affected are the tongue, hard and soft palate, pharynx, epiglottis, and larynx.
- The LMA sits above the larynx with its tip in the esophagus and opening over the larynx.
How the LMA Works
- The LMA is single-use, inflatable, covers the supraglottic area, and allows for ventilation but does not prevent aspiration.
- The device consists of a cuff, mask, valve, pilot balloon, inflation line, airway connector, and tube.
- Best tolerated in patients with low consciousness; otherwise, the patient may gag or remove the device.
Indications and Contraindications
- Indicated for poor airway (GCS 3) despite OPA/NPA, cardiac arrest where ETT cannot be placed, and as rescue after failed intubation.
- Contraindicated if gag reflex present, active vomiting, upper airway obstruction, distorted airway, or trismus/restricted mouth opening.
Advantages and Disadvantages
- Advantages: allows continuous chest compressions, is easy and quick to insert, enables one-handed ventilation, allows ETCO2 monitoring, and is less invasive than ETT.
- Disadvantages: not a definitive airway, difficult in high airway pressure situations, cannot use with trismus, and risk of aspiration.
Potential Complications
- Complications include poor seal, regurgitation, aspiration, kinking, laryngospasm, cough, airway trauma, dislodgement, and stomach insufflation.
Preparation & Equipment
- Prepare: LMA (size based on weight), Cobbs connector, securing device, lubricant, syringe, manual ventilation bag with filter and oxygen, ETCO2 monitor, and suction device.
- Use water-based lubricant and ensure all equipment is easily accessible.
Insertion Procedure
- Clear and position the airway, select and prepare LMA, lubricate cuff, and position patient supine with neck extended.
- Insert LMA by advancing over the tongue, inflate cuff to marked volume, check ventilation (chest rise), attach ETCO2, and secure device.
- If gagging, displacement, vomiting occurs, remove LMA and manage airway accordingly.
Post-Insertion and Troubleshooting
- Use Cobbs connector for less pressure on device, continue chest compressions if ventilation is adequate, and ventilate at 10 breaths/min.
- Troubleshoot by re-inflating cuff, re-inserting if displaced or folded, replacing damaged LMA, or managing complications (e.g., suction for regurgitation).
Key Terms & Definitions
- Laryngeal Mask Airway (LMA) — A supraglottic airway device for airway management.
- Supraglottic — Located above the vocal cords (glottis).
- Trismus — Jaw muscle spasm limiting mouth opening.
- Aspiration — Inhaling foreign materials into the airway/lungs.
- Gastric insufflation — Unintentional inflation of the stomach with air.
- End tidal carbon dioxide (ETCO2) — Measurement of CO2 in exhaled air to assess ventilation.
Action Items / Next Steps
- Review LMA skill sheet and PEEP guidelines.
- Watch the recommended video demonstration of LMA insertion.
- Prepare to practice LMA insertion and troubleshooting in a skills session.