A laryngeal mask airway (LMA) is used for assisted breathing in emergency situations and for patients who are undergoing surgery and require ventilation. The basic device consists of a soft, inflatable mask and a tube that reaches down into the patient’s throat. LMA intubation is the process of placing the tube into the throat, a procedure that is somewhat different using this device compared to using standard intubation techniques. The mask is inflated to hold the airway in place and to ensure that it fits the patient’s face properly.
Masks are available in different sizes to accommodate patients in virtually every size and age range. Selecting the wrong size can make it difficult to insert the tube, but in most cases there are sufficient indicators that choosing the correct one is not a problem. When performing LMA intubation, the patient’s mouth is opened and the curved tube is slipped into the mouth and throat, extending just a short way down the throat.
This system has certain advantages over other commonly used systems, among these that it can be placed quickly and does not require the use of a laryngoscope. LMA intubation is typically faster than other methods, the patient does not need to be given relaxants, and successful use of this device generally requires only the administration of a light anesthetic. Placement is usually very successful and even inexperienced medical personnel have close to a 100% success rate when attempting LMA intubation.
The original laryngeal mask is not recommended for patients who have not fasted, as some aspiration of stomach contents is possible. Newer versions of the product offer a way to block the esophagus and prevent aspiration, as well as a separate tube to empty the stomach once the mask is in place. Some models also have ribs or bars on them to ensure that the epiglottis is held out of the way, though this feature varies by manufacturer and by mask model. Contraindications for use of LMA intubation are patients who are morbidly obese and those who have growths or other types of airway obstructions.
Some types of the laryngeal mask are reusable as many as 40 times, but they require complete sterilization after each use. These are most commonly used by hospitals for surgical procedures, since they are set up to keep and clean other equipment as well. Disposable versions of the mask are appropriate for emergency rooms and for use by rescue personnel in the field, when retaining and reusing medical equipment can be more difficult.