Laryngeal Mask Airway (LMA) Insertion Technique

Originally designed for use in spontaneously breathing patients, it consists of a ‘mask’ that sits over the laryngeal opening, attached to which is a tube that protrudes from the mouth and connects directly to the anaesthetic breathing system. On the perimeter of the mask is an inflatable cuff that creates a seal and helps to stabilize it.

The use of the laryngeal mask overcomes some of the problems of the simple adjuncts:

1. It is not affected by the shape of the patient’s face or the absence of teeth.
2. The anaesthetist is not required to hold it in position, avoiding fatigue and allowing any other problems to be dealt with.
3. It significantly reduces the risk of aspiration of regurgitated gastric contents, but does not eliminate it completely.

Relative contraindication: 

1. Increased risk of regurgitation, for example in emergency cases, pregnancy and patients with a hiatus hernia. 

Technique for insertion of the standard LMA:

1. The patient’s reflexes must be suppressed to a level similar to that required for the insertion of an oropharyngeal airway to prevent coughing or laryngospasm.
2. The cuff is deflated and the mask lightly lubricated.
3. A head tilt is performed, the patient’s mouth opened fully and the tip of the mask inserted along the hard palate with the open side facing but not touching the tongue.
4. The mask is further inserted, using the index finger to provide support for the tube.
5. Eventually, resistance will be felt at the point where the tip of the mask lies at the upper oesophageal sphincter.
6. The cuff is now fully inflated using an air-filled syringe attached to the valve at the end of the pilot tube.
7. The laryngeal mask is secured either by a length of bandage or adhesive strapping attached to the protruding tube.
8. A ‘bite block’ may be inserted to reduce the risk of damage to the LMA at recovery.

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