SUPRA GLOTTIC

AIRWAY DEVICE

DR. DEBOJYOTI DUTTA

MODERATOR- DR.SUSHIL BHATI

S.M.S. MEDICAL COLLEGE

INTRODUCTION

Devices that are used to maintain the airway patency and provide

ventilation by placing just above the glottic opening.

They sit outside the trachea and provide a hands free means of gas

tight airway.

Standard of airway management , filling the niche between

facemask and tracheal tubes.

Dr. Archie Brain developed LMA in 1982 as a modification of

Goldman dental mask with ET tube.

The first commercially available supraglottic airway device was LMA-

Classic(1988).

CLASSIFICATION Based on Generation:-

LMA

First GenerationSimple airway device. Low pressure

pharyngeal seal

May or may not protect

from aspiration.

Have no specific design

to lessen the risk.Eg.-

cLMA

Flexible LMA

All LMs

Laryngeal tube

Cobra perilaryngeal

airway

Second GenerationSpecially designed for

safety.

High pressure pharyngeal

seal.

Reduce the risk of

aspiration.

May be more efficacious

in ventilation.

Eg.-

PLMA,Supreme LMA,

Laryngeal tube suction 2,

Laryngeal tube suction D,i-gel,

SLIPA.

CLASSIFICATION Based on sealing mechanism –

1.Cuffed perilaryngeal sealer:-

Non-directional non esophageal Sealers- cLMA, Flexible LMA, LMA

unique.

Directional Non-esophageal sealing- Fastrach LMA, ALMA.

Directional esophageal sealing- Proseal LMA, Suprem LMA.

2.Cuffed pharyngeal sealer:-

Without esophageal sealing: COPA, PAX.

With esophageal sealing: Combitube, LT, LTS.

3.Cuff less preshaped sealer: -

With esophageal sealing- Baska mask, i-gel.

Without esophageal sealing- SLIPA , AirQ-SP.

CLASSIFICATION

BASED ON THE NUMBER OF LUMEN-

1.Single Lumen Devices:-

LMA-classic, LMA-unique, LMA-flexible, ILMA, C-trach, Soft seal,

Laryngeal Airway Device(LAD), Ambu Laryngeal Mask,

Pharyngeal airway express(PAX), Cobra Perilaryngeal

Airway(CPLA), Laryngeal Tube(LT), Cuffed oropharyngeal airway,

Stream Lined Liner of the Pharyngeal Airway(SLIPA), Glottic

Aperture Seal Device.

2.Double Lumen Devices:- Proseal LMA, Combitube, Laryngeal Tube Suction(LTS), Airway Management Device(AMD).

3.Tripple Lumen Devices:- Elisha Airway Device(EAD).

INDICATION

Alternative airway during GA specially in short surgical

procedures and minor therapeutic or diagnostic procedures

like radiation therapy, diagnostic and interventional

radiology, endoscopy, ECT etc.

Cardiopulmonary resuscitation to secure the airway.

Essential part of difficult airway trolley.

Primary airway device when urgent airway patency is

required in lateral position as lesser time required to place

LMA in the lateral position as against endotracheal intubation

in this position.

Relative indication- in professional singers to avoid vocal cord

trauma.

CONTRAINDICATION

Limited mouth opening (< 2 fingers)

Local pathology in pharynx , larynx or upper airway.

Trismus, facial or upper airway trauma

Increase risk of aspiration- Morbid obese, > 14 week pregnant,

prior opiods medication, delayed gastric empting, acute

abdominal or thoracic injury, history of GERD, and hiatus hernia.

Reduced lung compliance/increase work of breathing

ADVANTAGES Increased speed and ease of

placement.

Less requirement of expertise.

Improved hemodynamic stability at induction and during emergence of anesthesia.

Minimal IOP and ICP changes during insertion.

Increase airway tolerance.

Lower frequency of coughing during emergence.

Improved oxygen saturation during emergence

DISADVANTAGE

Inadequate positive

pressure ventilation.

More chances of aspiration

of gastric content.

Sore throat.

Vascular compression and

nerve damage.

LMA- Classic

Comprised of three main components

– Airway Tube

– Mask

– Inflation line

Mask designed to conform to the

contours of the hypopharynx with its

lumen facing the laryngeal opening.

Made of medical grade silicone, it

can be autoclaved and reused many

times.

Seal pressure =25cmH2O

SIZE SELECTIONMask Size Patient size /Body Weight Maximum Cuff

Inflation Volume (Air)

1 Neonates/Infants up to 5 kg Up to 4 mL

1.5 Infants 5–10 kg Up to 7 mL

2 Infants/Children 10–20 kg Up to 10 mL

2.5 Children 20–30 kg Up to 14 mL

3 Children 30–50 kg Up to 20 mL

4 Adults 50–70 kg Up to 30 mL

5 Adults 70–100 kg Up to 40 mL

6 Large Adults over 100 kg Up to 50 mL

PREPARATION PRIOR TO

INSERTION

Select the proper size of LMA.

Inspect the LMA for any tear , blockage .

Slowly deflate the cuff to form a smooth flat wedge shape .

Over inflate: look for leak.

Use a water soluble lubricant to lubricate the posterior surface of LMA just prior to insertion.

Avoid excessive amounts of lubricant

-on the anterior surface of the cuff or

-in the bowl of the mask.

Avoid lignocaine jelly for lubrication .

INSERTION TECHNIQUE

Position: Neck flexed and head extended.

Use non-inserting hand to stabilize occiput.

Jaw should be pulled down by assistant.

LMA tube be grasped like a pen with index

finger pressing the point where tube joins

mask.

Place the tip of the LMA against the inner surface of the patient’s upper teeth.

Aperture facing forward, the tip pressed

upwards against the hard palate.

Mask is advanced into pharynx to ensure

that tip remains flattened and avoids the

tongue.

Continue.. Neck is kept flexed and head extended.

Press the mask into the posterior pharyngeal wall using the index finger.

Continue pushing with your index finger and guide the mask downward into position.

Grasp the tube firmly with the other hand and then withdraw your index finger from the pharynx.

Press gently downward with your other hand to ensure the mask is fully inserted.

Continue.. Inflate the mask with the

recommended volume of air.

Do not over-inflate the LMA.

Normally the mask should be

allowed to rise up slightly out of the hypo pharynx as it is inflated to find

its correct position.

Insert a bite-block or roll of gauze to

prevent occlusion of the tube.

Now the LMA can be secured

utilizing the same techniques as

those employed in the securing of

an endotracheal tube.

OTHER METHODS OF

INSERTION 1. Thumb index method.

2.Partial inflation method.

3.180 degree rotation method.

4.Laryngoscopy aided method.

5.Stylet aided method.

6.Insertion from the side of the mouth opening.

SIGNS OF CORRECT

PLACEMENT The slight outward movement of the tube

upon LMA inflation.

The presence of a smooth oval swelling in the neck around the thyroid and cricoidarea, or no cuff visible in oral cavity.

Ventilate the patient while confirming equal breath sounds over both lungs in all fields and the absence of ventilatory sounds over the epigastrium.

Part of LMA Position

Distal tip of silicone

cuff

Upper esophageal

sphinter

Sides of the cuff Pyriform fossa

Upper part of the cuff Tounge base

PROBLEMS Failure to press the deflated mask up against

the hard palate or inadequate lubrication or deflation can cause the mask tip to fold back on itself.

Once the mask tip has started to fold over, this may progress, pushing the epiglottis into its down-folded position causing mechanical obstruction .

If the mask tip is deflated forward it can push down the epiglottis causing obstruction

If the mask is inadequately deflated it may either

push down the epiglottis

enter the glottis.

INTUBATION WITH C-LMA 1.Blind intubation.

2.Fibrescope guided.

3.retrograde.

4.Lighted stylet guided.

5.Nasotracheal intubation.

DISADVANTAGES:-

1.Standard tube not long enough to insert.

2.Pilot tube may kincked.

3.Cricoid pressure make it difficult to pass the tube.

4.Paediatric-largest uncuffed tube too small to allow good seal for PPV.

5.Removal of the LMA disturbs the ET tube

6. PPV not always possible due to moderate pharyngeal seal.

7.More risk of aspiration

Steps to reduce the chance

of aspiration

Avoid in patients who are un-fasted, or have factors predispose to regurgitation.

Routinely test the cuff for defects before use.

Avoid lubricating the anterior surface of the mask, since the lubricant may be aspirated.

Insert the LMA only when adequate depth of anesthesia has been reached.

Avoid disturbing the patient during emergence from anesthesia.

Keep the cuff inflated till the patient is awake.

Action after aspiration

1. Do not attempt to remove

LMA.

2. Disconnect the circuit and

allow to drain the fluid while

head is down & to the side.

3. Suction the LMA & give 100% O2.

4. Ventilate manually with low

gas flow & small TV.

5. Evaluate tracheobronchial

tree & suction the remaining

fluid with FOB.

6. Intubate when aspiration

below vocal cords.

LMA - UNIQUE

Single use , PVC made , cheaper.

Tube – stiffer , Cuff- less

compliant.

Less rise of intracuff presuure

with N2O.

More difficult to insert.

Size same as cLMA.

FLEXIBLE LMA Flexometallic tube- narrower & longer.

Has a rigid preformed angle at the cuff.

Seal pressure=20cmH2O

More difficult to insert.

Introducer helps to stabilize the airway tube during insertion & it is removed once mask is in place.

It has a less incidence of dislodgement once placed.

More useful in head & neck surgeries, ENT and upper torso procedures where need to reposition the airway is prevalent

Problems- Disruption of spiral reinforce wire, Increased airway resistance , limits endoscope & tracheal tube passage , unsuitable for MRI.

AMBU AURA LARYNGEAL

MASK Ambu Auraonce- single-use LM with a

preformed curve.

The Ambu Aura40 is the reusable, silicone version of the Ambu AuraOnce.

The Ambu Aura-i designed to facilitate intubation like ILMA.

Three parts- an airway tube, a mount area, and a bowl including the inflatable cuff..

All these three areas are molded as single unit for extra safety - no separation..

Facilitate insertion without exerting force on the upper jaw in neutral position.

A reinforced tip reduces the risk of the device folding back during insertion.

integrated inflation line and no epiglotticbars at the airway orifice.

SOFT SEAL LARYNGEAL MASK

similar to the single-use LMA.

The ventilation orifice is wider and it is characterized by the absence of mask aperture bars.

Cuff is more elliptical.

insertion with the cuff partially inflated is

recommended.

A maximum intracuff pressure of 60 cm

H2O is recommended.

may be used as an intubation conduit.

The large bowl of the device and its PVC

Construction inhibit easy insertion.

PERILARYNGEAL AIRWAY single use, PVC made, latex free .

It has a breathing tube with a large inner

diameter to increase air flow.

In the proximal end it has a standard 15 mm

connection

Novel head design- Grill of soft bar with Cobra

head shape.

Lies infront of laryngeal inlet.

Tip deflects epiglottis.

Bars allow ventilation & instrumentation.

Internal ramp to guide ETT to wards glottis

Proximal high volume low pressure cuff- seals

hypopharynx.

PLA offers a more effective seal, and a better

fiberoptic score as the c-LMA.

ADVANTAGES

1. Easy to insert.

2. Large lumen allows larger ETT &

fibrescope.

3. Sealing pressure higher than C-

LMA.

4. Can be used for parcutaneousdilatational cricothyroidotomy.

DISADVANTAGES

1. Less airway protection –

as tip lies above the

oesophageal inlet.

2. Airway obstruction.

INTUBATING LARYNGEAL

AIRWAY medical-grade silicon and latex free.

airway tube is curved similar to the anatomical curve of the upper airway to eliminate the need to bend the tube further during use, which can lead to kinking.

Mask- keyhole outlet to direct ETT to laryngeal inlet.

3 ridges – on inflation of mask, these ridges move against the posterior pharynx and improve anterior mask seal.

After intubation , ILA can be removed without dislodging the ETT using a reusable "ILA Removal Stylet”.

Low airway seal, high risk of aspiration.

INTUBATING LMA A modification of the c-LMA.

A rigid (stainless steel) anatomically

curved,short & wide bored shaft that

follows the anatomical curve of the palate

and the post pharyngeal wall.

An epiglottic elevator bar at the mask

aperture

Armoured flexible ET tube with a

longitudinal and a horizontal black line-

coincides with the epiglottic elevating bar.

The Stabilizer Rod of 25cm.

Seal pressure=60cmof H2O max.

Body

weight

ILMA size Air

volume

Tracheal

Tube

30-50kg 3 20ml 7mm

50-70kg 4 30ml 7.5mm

70-100kg 5 40ml 8mm

INSERTION Position: Neutral

Hold rigid handle parallel to patient’s chest.

Glide the mask along the palate till the straight part of the rigid tube is

parallel to the chin.

Rotate the rigid handle directing towards patient’s nose till it can not

be advanced.

Inflate the cuff & check ventilation.

Introduce FETT with black line faceing rigid handle till 15 cm mark.

Now grip ILMA handle firmly and lift it forward by few mms without

levering.

Advance the tube using clinical judgment.

Inflate the cuff and check for tracheal intubation.

Continue..

After confirmation of tracheal intubation deflate the ILMA cuff.

Remove FETT connector

Insert the stabilizing rod in the FETT to keep it in place.

Remove the ILMA gently over the stabilizing rod until it is clear of the

oral cavity.

Stablize the FETT to prevent accidental extubation.

Remove ILMA and the stabilizing rod.

Reconnect FETT connector and the breathing circuit and

confirm position again

CHANDY’S MANEUVER They increases the seal pressure and aligns the axes of trachea and

FETT.

First step : Rotating ILMA in coronal & sagittal plane in an attempt to

find least resistant ventilation position.

Second step : is to grasp the handle and use it to draw LMA forward

2-5 mm in a lifting action without levering teeth.

ADVANTAGES

Useful in “can’t intubate, can’t ventilate” scenarios.

Allows fast insertion into correct position without moving patient’s head or neck.

Can be used alone or as a guide to intubation.

Facilitates ventilation between ILMA insertion and ETT insertion

Good conduit for fibreopticintubation in presence of blood or clot in oral cavity.

Difficult laryngoscopic view is irrelevent to the success of ILMA intubation.

DISADVANTAGES

More likely to dislodge in head or

neck manipulation.

Unsuitable for MRI.

Difficulty in insertion with limited

mouth opening.

On removal of ILMA , tracheal tube

can be displaced downwards.

PROSEAL LMA

Reusable , silicon made , most specialized modification of c-LMA.

Modifications:-

(i) oesophageal drain tube

(ii) posterior inflatable cuff

(iii) reinforced airway tube

(iv) integral bite block

(v) introducer

Higher leak pressure(35cm of H2O)

than c-LMA(25cm of H2O).

Size- in 7 sizes (1-5) like the C-LMA with

drainage tube of

8,10,10,14,16,16&18 Fr respectively.

INSERTION (i) Standard: identical to the cLMA, but demanding

careful attention to detail.

(ii) Introducer: a metal introducer is attached to the concave side of the device. It is then introduced in the same manner as an intubatingLMA.

(iii) Bougie-guided: a bougie is placed upside down into the oesophagus and the PLMA is railroaded into place via the drain tube (suction catheters or orogastric tubes are alternatives).This technique had a significantly higher success rate.

Positioning:- The easy passage of an orogastric

tube into the stomach via the oesophageal tube has been shown to correlate with optimal

anatomical airway positioning over the larynx.

ADVANTAGES Increased airway seal improves the PPV.

Decreased chance of aspiration-

1.Oesophageal opening is isolated from the airway.

2.Drain tube vents gas leaked into the oesophagus.

3.On regurgitation drain tube vents the fluid & small solid particles

beyond the pharynx.

4. The large bulk of the PLMA reduces the space available for

regurgitated fluid to ‘pool’.

5. Increased oesophageal and pharyngeal seal decreases the risk

of any pooled fluid entering the laryngeal inlet.

Simple tests enable correct positioning of the PLMA to be confirmed.

The stomach may be accessed with an orogastric tube.

DISADVANTAGES

1. Less suitable as an intubating device as an ILMA b/c narrow

airway tube.

2.Slightly longer time required to insert than C-LMA.

3.Can cause airway obstruction by- compression of supraglottic

structure or cuff in folding.

4.Contraindicated for intraoral surgery .

LMA - SUPREME

Single use, PVC made 2nd

generation LMA.

Has features of P-LMA, I-LMA & LMA unique.

(i) Single use , PVC- (cf.LMA unique).

(ii) Large inflatable plastic cuff, but no posterior cuff (cf. PLMA)

(iii) Oesophageal drain tube

(iv) Preformed semi-rigid tube

(v) Fins in the mask bowl to prevent epiglottic obstruction(cf. PLMA, cLMA)

Pharyngeal seal is intermediate between cLMA and PLMA( 26–30 cm H2O)

Oesophageal seal not reported.

ADVANTAGES

The reinforced tip reduces the risk

of fold-over, compared with the

PLMA.

Anatomic curve that facilitates

easy insertion.

A drain tube to allow gastric

aspiration.

A high volume/ low pressure cuff

which generates higher seal pressure (36.1 vs 27.4cm H20 of

LMA unique).

A built-in bite block and fixation

tab to help secure the airway

4- An oval airway cross section

for improved stability of the

airway

DISADVANTAGES

drain tube runs through the middle

of the airway tube (rather than next to it in the PLMA) dividing it

into two narrow lumens. This limits

its use for airway inspection

and for use as a conduit for

intubation.

Being made of PVC, the SLMA

may cause more trauma than

silicone devices

LMA C-Trach Enables combined ventilation,

visualization, and intubation.

High first attempt intubation success rate

of 91%.

Fiberoptic technology allows real time

visualization of the glottic opening and

of the ET tube passing through the vocal

cords.

Ideal in rescue/difficult airway situations

.

Completely portable and wireless system

weighs less than eight ounces.

Easy to learn and very effective

INSERTION

Inserted exactly the same as the LMA Fastrach.

Once the airway is secured and patient is being ventilated

The viewer is switched on, placed in the magnetic connector and a clear image of the larynx is displayed in real time.

The ET tube can be viewed as it enters the trachea. Once the patient is intubated, the viewer is removed and the mask is removed leaving the ET tube in place.

Problems:-

1. It has a poorer image quality than a flexible fiberoptic endoscope.

2. It cannot be used easily in the patient with a limited mouth

opening.

3. The view may be obstructed by secretions, lubricant, or blood.

i-GEL Novel SAD designed by UK anaesthetist,

Muhammed Nasir.

(i) Single use.

(ii) Cuffless: the mask is made of a soft polymer and is shaped similarly to an inflated LMA posteriorly with its anterior shape designed to ‘fit the perilaryngealstructures’.

(iii) Narrow-bore oesophageal drain tube.

(iv) Short, wide-bore airway tube.

(v) Integral bite block

(vi) Contains an epiglottic rest at the anterior part of the cuff which reduces the possibility of epiglottis ‘down folding’ and airway obstruction.

Continue…

Mask is made of a thermoplastic elastomer (SEBS-Styrene Ethylene

Butadiene Styrene) that has the flexibility and feel of human tissue. . After placement, body heat from the patient activates the gel component of this airway which expands to fill the void in the hypopharynx where the device rests.

Advantages:-

1. easy to insert: due to a combination of a very,very low coefficient

of friction when lubricated & absence of cuff.

2. truncated tip, with the aim of reducing post-use dysphagia.

3. wide lumen make it well worth for both airway rescue and as a

conduit for assisted intubation.

4. A gastric channel allows for suctioning and placement of a nasogastric tube.

5.Though oesophageal seal is low but enough (according to the manufacturer).

LARYNGEAL TUBE

multiuse, latex-free, single-lumen silicon tube

two low pressure cuffs (proximal and distal).

The distal balloon (esophageal balloon) seals the airway distally

The proximal balloon (oropharyngeal balloon) seals both the oral and nasal cavity.

Two anterior ,oval ventilating vents between the cuffs.

Cough pressure 60cmH2O

4 types- LT, LT-D, LTS-II, LTs-D

INSERTION Open the mouth app. 3 cm using

the thumb and index finger technique in neutral position of head.

Hold like a pen in the area of the teeth marks (three black marks).

Insert centrally along the hard palate into the hypopharynx.

Advance until a slight resistance is felt. The center black line should n be level with the upper front teeth.

Inflate the cuffs considering the respective colour code.

Connect bag to the 15 mm standard connector.

place the tube deeper, inflate the cuffs and withdraw until ventilation is optimized results in the best depth of insertion because tissue is retracted away from the laryngeal inlet.

SIZE VOLUME(ml)

0 10

1 20

2 35

2.5 45

3 60

4 80

5 90

ADVANTAGES

1. Easy insertion.

2. 2.High ventilation pressure can

be used.

3. Better protection from

aspiration.

4. Can be used to intubate the

trachea.

DISADVANTAGES

1.Airway obstruction.

2.Displacement on head &

neck movement.

3. Cuff rupture

4. Trauma to pharynx.

ESOPAHGEAL- TRACHEAL

COMBITUBE PVC double lumen supraglottic

airway device with two inflatable balloons

2 Lumens: tracheal and pharyngeal

Ventilation -either tracheal or esophageal intubation

95% of cases tube enters the esophagus

Proximal balloon-seals the oral and the nasal cavity

Distal balloon - seals either the esophagus or the trachea, depending on which of these the ETC has been sited.

Size- 37 Fr for height up to 5 ft.

41 Fr for height above 5.5 ft.

Between 5-5.5ft – either of these.

INSERTION Neutral position. Lift the tongue and

lower jaw upward to open the oropharynx .

Lubricate the tube with sterile, water soluble lubricant.

Insert the Combitube so that it curves in the same direction as the natural curvature of the pharynx .

If resistance is met, withdraw tube and attempt to reinsert.

Advance tube until the patient’s teeth are between the two black lines.

Inflate the blue pilot cuff with 100ml of air from the large syringe.

Inflate the white pilot cuff with 15ml of air from the small syringe.

Begin ventilation through the longer tube . If auscultation of breath sounds is good and gastric inflation is negative, continue and vice versa.

INDICATION

1. Patients in irreversible

respiratory arrest (i.e.

narcotic overdose,

hypoglycemia).

2. Patients in cardiac arrest.

3. Ventilation in

normal/abnormal airways

4. Failed intubation

5. Unconscious patients without

a gag reflex, and in need of

ventilatory support

CONTRAINDICATION1. Intact gag reflex

2. Under 4 feet tall & Under 16

years of age

3. Conscious – arouseable

patient

4. Known esophageal disease (cancer, varices)

5. Ingestion of caustic

substances

6. Stoma or functional surgical

airway

7. Partial or complete FBAO

8. CONSIDER: Latex Allergy

ADVANTAGES

1. Requires minimal training

2. May be more useful in non-

fasted patients

3. Successful passage and

ventilation in many patients via

esophageal route

4. Portable, useful in remote

setting

5. Functions in either the trachea

or esophagus

DISADVANTAGES1. Only adult and small adult

sizes

2. Potential for esophageal

trauma

3. Problems maintaining

seal in some patients

EASY TUBE The Easy Tube is new disposable,

polyvinyl -chloride, double-lumen, latex-free, supra-glottic airway device.

It has a close design to the Combitube, intended to be more friendly to use.

Allows ventilation in either esophageal or tracheal position, however it is expected to enter the esophagus in most cases.

However, the Easy Tube had a better fiberoptic view and a shorter time to achieve an effective airway, with similar ventilatory performances with the ETC

STREAMLINED LINER OF THE

PHARYNGEAL AIRWAY Plastic made, uncuffed, disposable ,2nd

generation SAD.

Anatomically pre-shaped to line the pharynx.

Hollow & boot shaped distal part-

1. Toe- rest in the oesophageal entrance.

2. Bridge- fits to the pyriform fossa.

3. Heel- anchor in correct position & connect the airway tube.

4. Two lateral bulges- relieve pressure on Hypoglossal& recurrent laryngeal NV.

5. Large capacity chamber-store regurgited fluid.

Available in 6 sizes- relate to dimension across the bridge: 47, 49, 51, 53, 55, and 57 mm.

ADVANTAGES

1. Easy to insert.

2. Greater airway sealing pressure.

3. N2O has no effect on sealing

pressure- as no cuff.

4. Effective protection against

aspiration during PPV

CONTRAINDICATEDUpper airway

abnormality.

CUFFED OROPHARYNGEAL

AIRWAY PVC made , single use ,1st generation.

The distal cuff inflate below the soft palate, behind the tongue, above the epiglottis, and within the oropharynx.

Available in five sizes: 7, 8, 9, 10, and 11 cm length with cuff inflation volume of 20, 25, 30, 35, and 40 ml respectively.

Insertion like Gudel’s oropharyngealairway.

COPA is recommended for use in spontaneously breathing patients with no risk factors for aspiration.

It is quick and easy to place.

Easy size selection & low cost.

Less airway protection

ELISHA AIRWAY DEVICE

Silicon made , latex free, latest.

three separate channels for ventilation,

intubation, and gastric tube insertion.

Ventilation channel (VC) and Intubation channel (IC) are side-by-side but join at the ventilation outlet situated in front of the laryngeal inlet.

The VC has a standard 15 mm

connector at th proximal end.

The IC allows passage of an 8.0 mm ET

tube for blind or fiberoptic-guided

intubation.

Gastric tube channel (GTC) has an

outlet located in the distal end of the

device.

Two high-volume, low-pressure cuffs.

Proximal cuff seals the oropharynx and nasopharynx & distal

cuff seals esophagus.

Both are inflated through a single pilot port with 50 cc of air

resulting in an intra-balloon pressure of approximately 70 cm

H2O.

Provide combination of 3 functions in a single device:

ventilation, intubation (blind and/or fiberoptic-aided) without

interruption of ventilation, and gastric tube insertion.

OTHER NEWER SAD

Eldor Laryngeal Airway.

Glottic Aperture Seal Airway.

Glossopalatine Tube. Etc.

EFFICACY VS SAFETY

For the evaluation of efficacy (absolute & relative ) small clinical

trials can be used.

Contrary, evaluations of safety (like ventilation failure rates , more

pertinently the risk of aspiration ) may need studies in larger scale

with larger populations.

Therefore the risk profile of a new device (unless it is particularly

unsafe) is unlikely to be established for several years after

introduction.

SUMMARY

There is no solid evidence of any device performing better than the classic LMA among the first generation SADs.

In the second-generation SADs- The PLMA proved top be very efficacious and safe in both routine and advanced uses

SAD with a drain tube has become the first choice as the standard of care.

Other newer SADs like i-gel, SLMA, and LTS-II have increasing positive evidence of their superiority.

All these developments in the field of SAD paved the way to take an ever larger role in modern airway management.