It is placed blindly in the oropharynx and the cuff is inflated with large volume of air tat is about 30 to 40 ml for a adult size tube. The inflated cuff of the Laryngeal Mask Airway seals the lateral and posterior pharyngeal walls and patient can be ventilated through ventilation ports.
Indications of Laryngeal Mask Airway or LMA :
- LMA is used as an alternative to intubation where difficult intubation is anticipated.
- LMA is also useful for securing airway in emergency where intubation and mask ventilation is not possible.
- Laryngeal Mask Airway is used as an elective method for minor surgeries where anesthetist wants to avoid intubation.
- LMA can be used as a conduit for bronchoscopes, small size tubes, gum elastic bougies.
Advantages of Laryngeal Mask Airway or LMA :
- LMA is easy to insert (even paramedical staff can insert).
- Laryngeal Mask Airway does not require any laryngoscope and muscle relaxants.
- It does not require any specific position of cervical spine so can be used in cervical injuries.
Disadvantages of Laryngeal Mask Airway or LMA :
- It does not prevent aspiration so should not be used for full stomach patients.
- High incidence of laryngospasm.
Contraindications of Laryngeal Mask Airway or LMA :
- Full stomach patients.
- Hiatus hernia, pregnancy (where chances of aspiration are high).
- Oropharyngeal abscess or mass.
1. Intubating LMA: Up to 8 no. endotracheal tube can be guided through it.
2. Proseal LMA: It has larger cuff and drain tube (which is used to prevent epiglottis from occluding the airway tube). It is more suitable for patients who have decreased pulmonary compliance and have high airway resistance.
LMA are available in 7 different sizes the smallest one for neonate and largest for large adults.