Dr. Rupak Bhattarai

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LARYNGEAL MASK AIRWAY (LMA)

• Dr. Rupak Bhattarai
• Taishan Medical University

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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.

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PARTS OF LMA

• THE CUFF
• THE APERTURE BARS
• THE AIRWAY TUBE
• THE CONNECTOR
• THE INFLATION LINE
• THE PILOT BALOON
• THE VALVE

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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.

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PROSEAL AND FASTRACH
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• 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.

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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.

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INTERNAL VIEW OF PLACEMENT OF LMA
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Sizes of LMA

• No 1 For infant with weight less than 6.5 kg.
• No2 Child with weight 6.5-20 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.

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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

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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).