Mowell Silicone Laryngeal Mask Airway

The laryngeal mask airway is a safe and reliable airway management device. This review describes the insertion techniques, advantages, limitations, and potential applications of the laryngeal mask airway in neonates. The standard version, made of medical grade silicone, consists of an oval shaped mask with an inflatable outer rim; a wide bore airway tube, which originates from the back plate, is joined at the proximal end with a 15 mm standard connector. The two aperture bars in the middle of the mask lumen, opposite to the distal end of the airway tube, are intended to prevent obstruction of the tube by the epiglottis. The black line running along the shaft helps to detect any subsequent rotation of the mask on the tube axis.

RANGE, SIZES, AND INSERTION TECHNIQUES OF THE LMA (Laryngeal Mask Airway)

1. Use the correct size of LMA for the patient. Size 1 is suitable for neonates weighing 2.5–5 kg.11 It has been postulated that a smaller size (0.5) could be useful in preterm newborns. However, there are reports of successful use of size 1 in preterm neonates weighing 0.8–1.5 kg.12–15
2. Fully deflate the cuff as described in the manual, and lubricate the back of the mask tip (for neonates in the labour ward, lubrication may not be necessary, as oral and pharyngeal secretions may reproduce this function).
3. Press (flatten) the tip of the LMA against the hard palate. During this manoeuvre, the operator should grasp the LMA like a pen with the index finger at the junction between the mask and the distal end of the airway tube.
4. Gently advance the LMA with one single movement, applying continuous pressure against the palatopharyngeal curvature with the index finger. The vector of the force applied must be directed cranially and not caudally.
5. Continue pushing the LMA against the soft palate so that the cuff passes along the posterior pharyngeal wall and the tip locates itself in the hypopharynx—that is, it cannot be pushed further inwards.
6. Inflate the mask to the minimum air volume necessary to establish an adequate seal. The maximum recommended volume for each size is rarely required. Do not hold the shaft of the LMA during cuff inflation, as the shaft may be observed to move outwards during cuff inflation allowing correct positioning.
7. Connect the proximal end of the airway tube to a device (bag, ventilator) for PPV.
8. Correct LMA positioning can be evaluated by observing synchronous movements of the chest and by neck auscultation.