What is a Laryngeal Mask Airway (LMA)?

What is a Laryngeal Mask Airway (LMA) ?

​The LMA is a supraglottic airway device that was first designed for elective ventilation in the operating room. The use of the LMA is an often preferred alternative to bag-valve-mask ventilation allowing the healthcare provider to monitor the patient rather than holding the mask in place. ​The LMA is also minimally invasive and designed specifically for airway management in the unconscious patient. Subsequently, an inflatable mask is fitted with a tube that exits the mouth to permit ventilation of the lungs.

History of the LMA

The laryngeal mask airway (LMA) is a supraglottic airway device developed by British Anesthesiologist Dr. Archi Brain. It has been in use since 1988. 

Types of Laryngeal Mask Airways

The LMA comes in an assortment of sizes and styles. The different types of laryngeal mask airways include:
​
1. LMA Classic: the original, reusable device
2. LMA Unique: a disposable version that works well in the field
3. LMA Fastrach: an intubating LMA that easily precedes intubation
4. LMA Flexible: softer tubing, not appropriate for emergency situations
5. LMA ProSeal: used to suction gastric contents, not appropriate for emergency
6. LMA Supreme: similar to the ProSeal, but includes a built-in bite block
7. LMA CTrach: includes built-in fiber optics with a video screen

When Do You Use a LMA?

The LMA is used as temporary airway during anesthesia or as a life-saving measure when respiration is not present. The LMA is often useful in the operating room, intensive care unit, emergency room, and by paramedics and EMT's.

The Anatomy of the LMA

​The LMA consists of an endotracheal tube that connects to an elliptical mask on the distal end. The mask features a cuff that forms an airtight seal on the glottis once it is in place. The mask of the LMA is inserted first, with the mask covering the glottis and the tube extending out of the patient’s mouth.

LMA devices range in size from 0 for an infant to 6 for a large adult. The specific size is determined by the age and weight of the patient. When a patient is between mask sizes, the larger size is usually recommended to ensure a secure seal.

How To Insert an LMA

To insert an LMA, follow these steps:

1. Inflate and deflate the cuff to check its volume and ensure there are no leaks.
2. Apply the lubricant to the posterior surface of the mask.
3. Pre-oxygenate the patient with bag-valve-mask ventilation if possible.
4. Position the patient in the sniffing or "neutral" location.
5. Insert the LMA and manually guide it along the hard and soft palates and into the throat by pushing with the index or long finger in the v-shaped notch where the tube attaches to the mask.
6. Use minimal pressure to advance the LMA until you encounter resistance.
7. After the LMA is in place, then inflate the cuff.

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