Laryngeal Masks

Soon after the laryngeal mask airway became popular in elective anesthesia it became apparent that the device had a distinctly valuable role in cannot intubate, cannot mask ventilate situations. Cricothyrotomy, whether using an open or percutaneous technique, has an average time requirement of 75-100+ seconds. The LMA, and other supraglottic ventilation devices, such as the iGel, AirQ, and King LT, can provide ventilation in less than 20 seconds. Additionally, the performance of these devices is not affected by the patient characteristics that negatively affect mask ventilation, laryngoscopy, and surgical airways (such as obesity, limited neck movement, facial hair, etc.). Having a means of rescue ventilation should intubation and mask ventilation fail is a requirement for safe practice in emergency airway management.

LMA Unique positioned over laryngeal inlet in pharyngeal model (center) and on lateral neck radiograph (right).

Laryngeal Mask Airway (LMA North America)

1) Wedge-shaped inflatable mask fits over larynx, creating seal within upper airway. Patient must have absent gag reflex.

2) Tip of wedge fits into upper esophagus and bowl of mask covers laryngeal inlet. Minimal regurgitation protection.

3) Numerous models including disposable version (LMA Unique) and intubating LMA (Fastrach).

4) Numerous sizes from pediatric to adult; typical adult female requires #4 LMA, typical adult male #5 LMA.

5) Recommended insertion technique (LMA Unique, Classic): With mask deflated, lubricate undersurface, using fingers at base of bowl, push mask down throat, up against palate, and backward to posterior hypopharynx, until bowl is around curvature of tongue.

6) Best seal pressure is with under-inflation of mask; recommended volume is 30 cc for #4 , and 40 cc for #5--many users start with half this volume and listen over the neck for a cuff leak. If cuff leak, try smaller mask volume or larger LMA.

7) Cricoid pressure prevents optimal placement and pushes tip out of upper esophagus.

The LMA Fastrach: A unique device capable of rescue ventilation and blind intubation (LMA North America)

LMA Fastrach features:

1) A short, large-bore tube section;

2) an epiglottis elevating bar

3) a custom designed, flexible tracheal tube

Tube pushes up the epiglottis elevating bar as it passes. Soft tip, flexible tube exits at a low trajectory to pass into trachea.  Fastrach LMA now available in single use version.

LMA Fastrach Insertion Technique Size 4 recommended for most adult females, 5 for most males. Lubricate back of mask. Fastrach must be rotated into proper position. Start by having curved tube contact chin, then roll backward.   Advance by keeping back of mask in contact with soft palate and posterior pharynx as it is placed. Do not lift upward on handle at this point, as this can cause down-folding of epiglottis. On full insertion, the tube section of the device is oriented somewhat caudally, parallel to the inner surface of upper incisors.   A slight withdrawal and reinsertion of the device helps advance the tip of the mask under the epiglottis. The mask is then inflated. Many clinicians use less than the recommended inflation volumes marked on the handle. Bag the patient and optimize ventilation by slight adjustment of the handle. Capnographic wave forms are the ideal way to verify proper location of the mask over the laryngeal inlet before blind intubation.

If resistance is felt, try repeating “in-out” maneuver of mask and reinserting tube.   AIRWAY CAM is a distributor of LMA products, including the LMA Fastrach and LMA Supreme. BUY LMA PRODUCTS HERE

The air-Q is a single use supraglottic airway with advanced design features for both ventilation and fiberoptic intubation (Cook Gas Inc.)   1) Easy insertion due to mask shape and firmness of leading edge. Mask tip does not fold down or back upon insertion. 2) Undersurface of mask has broad flat shape that promotes midline placement, lateral stability, and ideal supraglottic position. 3) Removable connector, short wide-bore tube section, and keyhole outlet all facilitate fiberoptic intubation.

The I-gel: a single use supraglottic airway without an inflatable cuff (Intersurgical Ltd., Wokingham UK)   1) Mask is made of a thermoplastic elastomer (SEBS-Styrene Ethylene Butadiene Styrene) that has the flexibility and feel of human tissue. Upon insertion, it adapts to the patient’s airway. 2) Advanced anatomic mask design mirrors perilaryngeal anatomy and provides effective seal without a cuff. 3) Firmness of material and tip design permit easy insertion, without back-folding of leading edge. Lateral stability and midline positioning are promoted by broad back of mask and buccal cavity stabilizer. 4) A gastric channel runs from the proximal connector to the mask tip and allows for suctioning and placement of a nasogastric tube.