The laryngeal mask airway.

The laryngeal mask airway (LMA) is a new concept in airway management. A miniature inflatable mask is positioned in the hypopharynx, forming a low-pressure seal around the laryngeal inlet. The mask is attached via a tube to the breathing circuit. It is inserted after induction of anesthesia without the need for muscle relaxants or laryngoscopy. The LMA can be used to facilitate both spontaneous and controlled ventilation in adults and children. The LMA has been used for a wide variety of surgical procedures but is probably best suited to short procedures, especially if a light general anesthetic is used in combination with a regional technique. It may be particularly useful in outpatient anesthesia, as it avoids the need for intubation or muscle relaxants. It can be used as an alternative to mask anesthesia or when an endotracheal tube would have been inserted to allow surgical access. It has been used successfully in cases of difficult or failed intubation, although its role here needs further appraisal. It does not protect against aspiration of stomach contents and should not be used when aspiration is a risk. Controversy exists regarding its use to facilitate positive-pressure ventilation (PPV) due to concern that gases under pressure may be forced into the stomach and predispose the patient to regurgitation. It may be more difficult to use in children. It is now widely used in the United Kingdom; however, it is not yet available for sale in the U.S. It has already had a major effect on practice in Britain and has the potential to do the same in the United States.