The document discusses the history and use of laryngeal mask airways (LMA). It describes how Dr. Brain developed the first LMA prototype in 1981 as a supraglottic device that sits outside the trachea but provides an airway. Over time, different types of LMAs were developed including the classic LMA, ProSeal LMA, reinforced LMA, LMA-Unique, and Supreme LMA. The document outlines the features and proper insertion technique for each LMA and discusses their advantages, such as being less invasive than endotracheal tubes, as well as potential complications if not properly placed.

1. Laryngeal mask airway
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu), Dip. Diab.
DCA, Dip. Software statistics-
PhD ( physiology), ( IDRA )

2. Supraglottic device – the first
• standard fixtures in airway management, filling a
niche between the face mask and the tracheal tube
in terms of both anatomical position and degree of
invasiveness.
• These devices sit outside the trachea but provide a
hands-free means of achieving a gas-tight airway.

3. History
• Archie Brain –
• Supraglottic approach was less traumatic
• Gold man mask in his dental anesthesia clinic
• Nasal mask was possibly similar to laryngeal
inlet
• Connected the tube with the rim
• Prototype LMA in 1981

4. From the internet for closed academic
purpose only

5. • 1983 – first published article in BJA
• 1985 Katz MD popularized the use in US
• Slowly commercial devices
• Replaced ETT in the use as such in number of
cases
• Various modifications !!

6. LMA – classic
• It consists of an oval soft silicone mask that
sits over the larynx with an integrated stem
that extends through the oral cavity to allow
attachment to the anaesthetic circuit or other
appropriate equipment.
• Mask when inflated, fits around the laryngeal
inlet and supports it in a position away from
the posterior pharyngeal wall

7. • Mask like a bowl continues as a stem to end in
a 15 mm male connector for a breathing
circuit
• Mask and stem – 30 degrees
• Inflatable mask – tube, pilot balloon , valve
• Grilles across the mask for preventing down
folding of epiglottis.
• Silicone rubber – 40 times autoclavable

8. Taken from internet for closed academic purpose only

9. INSERTION
TECHNIQUE
• Something like swallowing
• Deflate smooth, Fbs, pilot balloon
• Sniffing position
• Jaw assistant
pen hold – index at junction
Black line centre of upper lip
push for hard palate
Release pull assistant
cuff tip flat against palate --See folding of tip.

10. • Continue pushing with left
hand
• Resistance
• Anterior laryngeal
displacement
• Inflate to desired ml to see
LMA slightly coming out

11. • When properly placed, the mask rests on the
hypopharyngeal floor. The sides face the pyriform
fossae, and the upper border of the cuff is behind
the tongue base
• Other techniques
• Partially inflated
• Retromolar and turn
• Lateral in high arched palate
• Release cricoid pressure if not

13. Seals !!
• pharyngeal seal.
• During controlled ventilation efficacy is dependent on
factors such as whether the device orifice sits over the
larynx and the quality of the device seal with the
laryngopharynx
• esophageal seal
• Reducing aspiration risk requires a good-quality seal
with the hypopharynx and/or oesophagus

16. • If the epiglottis has downfolded, moving the
LMA up and down without deflating the cuff
may help to reposition the epiglottis. Another
maneuver is to withdraw for 5 cm and reinsert
• My fixing – gauze piece and a plaster as bite
block
• Intubate through LMA if needed
• Maintain anesthesia

17. Extubate LMA – my option
• Supraglottic device – hence patient
acceptance is better
• Small dose fentanyl , cut off agents , awake
• Reverse and totally awake
• Deflate – remove the LMA – ask the patient to
swallow
• No suction in LMA removal

18. • Although careful placement, cuff inflation, and adaptation
time improve the seal, leakage often occurs at 20 cm H2O
airway pressure with the classic LMA.
• Obesity, a head-down tilt, abdominal insufflation, airway
obstruction, or any other conditions necessitating
ventilation with high airway pressures increase the risk of
hypoventilation, gastric insufflation, and regurgitation

19. Taken from internet for closed academic purpose only

20. Advantage LMA !!
• Professional singers
• Remote locations
• Resuscitation
• Endoscopies
• ESWL

21. Complications
• injuries have been reported with LMA use, including
injuries to the epiglottis, posterior pharyngeal wall,
uvula, soft palate, tongue, and tonsils
• Sore throat
• Ventilate ? Change of head position ?
• rare complications include 12th cranial nerve
paralysis, unilateral hypoglossal nerve paralysis and
transient bilateral vocal cord paralysis

22. • If gastric contents are seen in the laryngeal
mask, the patient should be placed in the 30°
head-down position, the LMA left in situ,
anesthesia deepened,
• and the breathing system disconnected
temporarily to allow drainage and suctioning
of the airway tube.
• Intubate if aspirated

23. LMA-Unique
• The single-use LMA-Unique (disposable
laryngeal mask airway, DLMA) is made of
polyvinyl chloride and costs less than a
reusable LMA
• tube is stiffer and the cuff is less compliant.
• It may be helpful to warm the tube before
insertion

24. The reinforced (or flexible) LMA
• The reinforced (or flexible) LMA (sizes 2-5) is an
alternative version of the LMA in which the tube is
thinner, narrower and longer and is reinforced with a
spiral of steel wire to add flexibility and reduce the risk of
kinking;
• Difficult to insert. can rotate later
• Tongue bite safety , no in MRI
• But nasal surgeries , tonsils !!

25. Insertion of an LMA is
frequently difficult in
patients in whom
tracheal intubation is
difficult.

26. Proseal LMA ( pLMA)
Aspiration is the
danger?
Can we decrease
leak ?

27. • Drainage tube with a
ring
• No grille
• Cuff s- 2
• Anterior and posterior
• Reinforced tube
• - Hence narrower
• Bite block

28. pLMA
• Greater depth
• Technically more demanding insertion
• The device may be introduced digitally or with
a special introducer.
• Bougie to drainage tube and esophagus
• Bougie to larynx – straight to main tube
• Laryngoscope or a tongue depressor

30. Position ??
• (1) The PLMA may not be inserted sufficiently far, with the
consequence that the tip of the drainage tube lies in the
pharynx. Positive-pressure ventilation is ineffective because
delivered gas passes out the drainage tube.
• (2) The tip of the PLMA may lie within the glottis, thereby
obstructing ventilation and impairing function of the drainage
tube.
• (3) The tip may be folded over and obstruct ventilation and
the drainage tube.

31. Gel to proximal portion of drainage
tube
• The drainage tube gel does not move with positive-pressure
ventilation or brief firm pressure applied to the sternum.
• The drainage tube gel does not move when airway pressure is
raised to 20 cm H2O.
• The drainage tube gel moves slightly when brief “bobbing”
pressure is applied to the suprasternal notch (the mechanism
is pressure on the esophagus).( SS notch test )
• Catheter inside drain tube

32. Clinical pearls
• Can we nebulize ??
• Pregnancy more than 14 weeks ??
• Prone position ??
• Classic 20 cm Vs 30 cm peak pressure for
pLMA
• Cuff pressure is 60 cm for both
• Limit of surgical duration – 2 hours but with
proseal 12 hours reported

33. Supreme LMA
• . Similar to the pLMA,
• sLMA has an improved cuff
design that produces higher
airway leak pressures,
• drainage tube that allows for
gastric access,
• integrated bite block
• Fixation tab to insert and to
find size

34. Summary
• LMA – history
• Types
• Classical insertion tecniques
• Indications and contraindications
• Merits and demerits
• Supreme
• pLMA
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