A laryngeal mask, also known as laryngeal mask airway is a medical device (supraglottic airway) which keeps the patient’s airway open during unconsciousness or anaesthesia. The mask has an airway tube which is joins an elliptical mask to a cuff that is inserted through the mouth of the patient to the windpipe where it is inflated and it forms a airtight seal on the top of glottis, thus preventing the airway from collapsing. Laryngeal masks are also usually used by anaesthesists to administer anaesthesia gas or oxygen into the lungs of the patient during surgery and by paramedics for unconscious patients and during emergency conditions.
The laryngeal mask was invented early 1980s by British anaesthesiologist Archibald Brain. In December 1987, the first commercial laryngeal mask was launched in United Kingdom.
History of Laryngeal Mask
Dr. Archie Brain started studying the anatomy and physiology of the upper airways and concluded that current methods for connecting artificial airways to the patient were not the best because there is no direct end-to-end junction; the face mask is sealed against the face and the endotracheal tube goes far beyond, as a result of which junction is created within the trachea instead of at the beginning. He recommended using fitting loop into the anatomical loop of space around the larynx, with a downward projection into oesophagus, which can be hollow to enable draining of regurgitant fluids.
Laryngeal mask airways come in several types, as follows:
- The LMA Classic- it is the original design and is reusable.
- The LMA Unique- it is a disposable mask, and is used for emergency and pre hospital setting.
- The LMA Fastrach- it is an intubating LMA which is designed to act as a conduit for intubation. LMA Fastrach has special features like insertion handle, epiglottic elevating bar to lift epiglottis, rigid shaft with anatomical curvature which increase the rate of successful intubation and do not restrict the size of the endotracheal tube. The LMA Flexible has softer tubing. It is not used the in the emergency setting.
- The LMA ProSeal- it has an additional channel for suction of gastric contents and also allows 50% higher pressures without any leak. But, it does not allow blind intubation and hence cannot be used in the emergency setting.
- The LMA Supreme- it has a newer design similar to the ProSeal and has a built-in bite block.
- LMA CTrach- it is like the LMA Fastrach and has built-in fiberoptics which can be connected to a video screen to visualize the larynx.