Laryngeal Mask Airway (LMA) The LMA designed by Archie Brain in 1988 is becoming increasing! y popular and is replacing the EIT for anaesthesia and maintaining the airway in many situations. It allows attachment to circuit, end-tidal monitoring, and acts as a route for EIT. ADVANTAGES OVER ETI • Simpler to insert and check placement (safer airway tool for non-anaesthetists) • Can be inserted without muscle relaxation and even with local anaesthesia • Well tolerated till awake and does not cause a sympathetic response • Can be used for IPPV without entering or traumatising the larynx and trachea • Protects the larynx from secretions and bleeding from above DISADVANTAGES • Contraindicated in "full stomach" as aspiration may occur • Contraindicated if ventilation requires high airway pressures e.g. obesity • Relative contraindication if access for adjustments is limited during surgery • High seal pressure on mucosa may cause posterior pharyngeal wall damage Selection of patient and procedure (comparing the risk of complications) are important considerations when deciding between the LMA and EIT. LMA size Patient Volume of cuff (ml) Neonate 4 1.5 / 2 Child 7-10 2.5 20-30kg 14 3 30 -50kg/adult female 20 4 Adult male 30 516 Large adult male 40 INDICATIONS • A hands free substitute for the oro-pharyngeal airway and facemask • Emergency resuscitation and CPR • Difficult intubation: airway maintenance when intubation fails (see page 4.25). • To facilitate intubation with a bougie or fibre optic instrument • IPPV with tidal volumes of <lOml/kg and Paw< 25 cm Hp PRE-USE CHECK is essential as the LMA maybe sterilised and re-used 50 times. Check for clear lumen, transparent tube and no kink on flexion to 180°. Cuff should hold the volume recommended +50% without herniation. 

INSERTION 1. Deflate the cuff fully, so that it curves back on itself. 2. Lubricate only the back (palatal) surface and the tip of the LMA. 3. Suppress pharyngeal reflexes with i. v. or volatile agent or LA. 4. Extend the head and flex the neck. 5. Hold the LMA at the junction of the cuff and tube. 6. Slide the tip against the hard palate and continue backward pressure till it passes the back of the tongue. Shift the fingers to the top of the tube and push the tube in till positioned. 7. Check that the black line faces the upper lip. 8. Inflate the cuff with adequate air to minimize air leak (up to 60cm Hp). 9. Insert a bite block and fix the tube bent southwards (ifnot flexible). 10. Connect to breathing system and check ETC02 and ventilation. INTUBATION USING A STANDARD LMA Use a size 6mm ETT with a size 4 LMA, and a 7mm with a size S LMA. 1. Insert the ETT through the LMA with the tip projecting. 2. Insert LMA, inflate cuff, and push the ETT further (may need to cut the epiglottis protection bands of the LMA). Check ventilation. Keep the LMA in till extubation. 3. If a larger ETT is needed: Insert a teflon introducer through the LMA into the trachea. Remove the LMA and rail road the ETT over the introducer. INTUBATING LMA The rigid silicone coated tube is curved to fit the palate and the pharynx, allowing easy insertion. The handle should be lifted at intubation. The epiglottis elevating bar allows passage of an 8mm ETT or fibreoptic bronchoscope and is useful for a difficult airway with limited head and neck movement. It allows ventilation and oxygenation throughout intubation attempts. LMA PRO-SEAL I SUPREME (curved) Double cuff design reduces mucosa! pressure and damage. Double tube design separates respiratory and alimentary tracts, and allows Paw>25cm Drain tube allows gastric suction and prevents insufflation. Pro-seal has an introducer. Avoid in full stomach except in emergencies (CPR and difficult intubations). LMA i·gel has 1. a soft non inflating cuff of gel which seals over the larynx and reduces sore throat, 2. an epiglottic rest, and 3. a bite block. LMACTrach A portable viewer gives a colour image direct view of the larynx and passage of ETT. It allows continuous ventilation and oxygenation during intubation. 4