LARYNGEAL MASK AIRWAY LMA Dr Rupak Bhattarai Taishan

LARYNGEAL MASK AIRWAY (LMA) Dr. Rupak Bhattarai Taishan Medical University

Laryngeal Mask Airway It is being increasingly used in place of a face mask or tracheal tubes during administration of an anesthetic, to facilitate ventilation. Also used in patients with difficult intubation.

PARTS OF LMA THE CUFF THE APERTURE BARS THE AIRWAY TUBE THE CONNECTOR THE INFLATION LINE THE PILOT BALOON THE VALVE

Types of LMA Generally four types of LMA used these days: The re-usable LMA The disposable LMA The proseal LMA which has an orifice through which naso -gastric tube can be inserted Fastrach LMA that facilitates intubating patients with difficult airways.

PROSEAL FASTRACH AND

An LMA consists of a wide bore tube whose proximal end connects to a breathing circuit and the distal end is attached to an elliptical cuff that can be inflated through a pilot tube.

Procedure of insertion of LMA The deflated cuff is lubricated and inserted blindly into the hypopharynx so that once inflated , the cuff forms a pressure seal around the entrance to the larynx. This requires the anesthetic depths slightly greater than the required for the insertion of an oral airway. The shaft of an LMA can be secured with tape. The re-usable LMA , which can be used after autoclave is made of silicon rubber and is available in many sizes.

INTERNAL VIEW OF PLACEMENT OF LMA

Sizes of LMA No 1 : For infant with weight less than 6. 5 kg. No 2 : Child with weight 6. 520 kg. No 2. 5 : Child with weight 20 -30 kg. No 3 : Small adult with weight greater than 30 kg. No 4 : Normal adult with weight less than 70 kg. No 5 : Large adult with weight greater than 70 kg.

Cuff volume (ml) for LMA No 1 : 2 -4 ml No 2: Up to 10 ml No 2. 5: Up to 15 ml No 3 : Up to 20 ml No 4: Up to 30 ml No 5 : Up to 30 ml

Contraindication for LMA insertion Pharyngeal pathology (e. g abscess). Pharyngeal obstruction. Full stomach patient. Pregnancy. Although LMA is clearly not a substitue for tracheal intubation but it has proven particularly helpful as a temporizing measure in patients with difficult airways because of its easy of insertion and relatively high success rate (95 -99%).