Airway Discussion

8/6/2019 Airway Discussion

1/30

Difficult Airway Case Discussion

DIFFICULT AIRWAY Case Discussion

Dr.P.Shanmuka Nagaraju

1. Describe the anatomy and physiology of the human airway ?

The airway extends from the nose or mouth to the terminal bronchioles.

The upper airway includes nose, oral cavity, pharynx, larynx, trachea and main bronchi.

NOSE :

The nasal cavity is divided into two halves by the nasal septum.

The entrance of each nostril is covered by skin with hair and is called the vestibule.

Nasal valves are the narrowest portion of the nostril and demarcate the vestibule from the nasal

cavity proper.

The columella is the strut at the caudal end of the septum between the two nostrils.

Floor of the nasal cavity is parallel to the hard palate.

Roof of the nose is tent shaped & the middle third of the roof is formed by the cribriform plate of the

ethmoid and houses the olfactory epithelium.

Nasal septum supports the dorsum of the nose, it consists of quadrilateral cartilage joined to the

vomer and the ethmoid bone.

The lateral wall of the nose has three projecting shelves of bone known as turbinates or conchae.

They serve to increase the surface area of the nasal cavity.

The turbinates are superior, middle, inferior and the space under each turbinate is called as

the meatus.

The nasolacrimal duct opens into the inferior meatus. The posterior ethmoidal sinus opens into the superior meatus.

The anterior & middle ethmoidal sinuses, maxillary sinus & frontal sinus opens into middle

meatus.

The sphenoidal sinus opens into sphenoidal recess.

Epithelium within the nose : Olfactory & respiratory epithelium.

Olfactory epithelium

confined to the superior part of the nasal cavity,

It is non ciliated, contains bipolar olfactory cells,

It extends medially on to the septum and laterally on to the superior turbinate. Respiratory epithelium

lines the rest of the nasal cavity.

It is a pseudostratified ciliated columnar epithelium.

Goblet cells and mucous glands are distributed throughout the submucosa.

Blood supply to the nose :

It is by both external & internal carotid arteries.

Superior part of the nose supplied by the anterior and posterior ethmoidal arteries which

are branches of the ophthalmic artery, which in turn is a branch of the internal carotid artery.

Remaining part of the nose supplied by maxillary artery, a branch of external carotid

artery.

Dr.P.Shanmuka Nagaraju 1


2/30


Littles area (Kiesselbachs plexus) is an area on the anterior septum where several vessels

anastomose and is the frequent site of epistaxis.

Venous drainage : to the ophthalmic and facial veins and the pterygoid and pharyngeal plexuses.

Nerve supply of the nose :

The nose receives sensory, special sensory and autonomic nerve supply.

Sensory nerve supply is by

Anterior ethmoidal nerve the ophthalmic division of trigeminal nerve.

Greater palatine nerve the maxillary division of trigeminal nerve.

Special sensory supply is by the olfactory nerves.

Autonomic nerve supply provides secretomotor and vasomotor control.

The sympathetic fibers arise from the first five thoracic segments of the spinal cord and

synapse in the superior cervical ganglion and the postganglionic fibres run with the

blood vessels to the nose. An increase in sympathetic tone causes vasoconstriction and

decreased secretion.

The parasympathetic supply to the nose is from the lacrimal nucleus with the fibers

leaving the brain stem in the nervus intermedius. They relay in the pterygopalatine

ganglion before entering the nasal cavity. An increase in parasympathetic tone causes

swelling and increased secretion from the nasal mucosa.

Functions of the nose :

The nose is the organ of smell,

It filters the respiratory gases off the dust particles of more than 4m in size.

It causes warming and humidification of inspired gases. This function is brought about by the

large surface area and rich vascularity of the conchae. The nose humidifies the air by 85% when it reaches the nasopharynx.

The mucus blanket of the nose moves backwards from the front of the nose to the postnasal

space in about 20 minutes.

The submucosa contains lymphocytes, eosinophils, mast cells, and macrophages. The

immunoglobulins (Ig), IgA, IgM and IgG are also present in the nasal mucosa. All help in

phagocytosis.

During quiet breathing, the resistance through the nasal passage accounts for more than 50% of

the total respiratory resistance. This is more than twice the resistance during mouth breathing.

Human newborn infants are obligatory nose breathers. This is due to cephalic position of the

epiglottis and close apposition of the soft palate to the tongue and epiglottis in neonates. This

makes mouth breathing more difficult than nose breathing.

In infants, a nasogastric tube significantly increases total airway resistance by as much as 50%

and may further compromise breathing.

ORAL CAVITY :

The oral cavity consists of the upper and lower dentition, the tongue and floor of the mouth, the hard

palate and the openings of the major salivary glands.

The anterior border of the tonsil is known as the anterior pillar of the fauces and marks the start of

the pharynx itself.



3/30


The oral cavity is lined by stratified squamous epithelium.

The blood supply of the oral cavity is from the branches of the external carotid artery.

The posterior one-third of the tongue is continuous posteriorly with the epiglottis, between these two

areas lie two small depressions known as valleculae.

The floor of the mouth is supported by the mylohyoid muscles.

The sensory nerve supply of the tongue :

Anterior 2/3rd

-- by lingual nerve, the mandibular division of trigeminal nerve.

Posterior 1/3rd

by glossopharyngeal nerve.

The gustatory sensation from the anterior 2/3rd

of the tongue is by facial nerve.

The motor supply of the tongue is by hypoglossal nerve.

The blood supply of the tongue is by lingual artery, a direct branch of the external carotid artery.

The oral cavity contains a complete ring of lymphoid tissue (Waldeyers ring), which comprises the

adenoids (pharyngeal tonsils), the palatine tonsils, and the lingual tonsils.

PHARYNX :

The pharynx is topographically and functionally divided into three parts :

nasopharynx,

oropharynx and

laryngopharynx.

Nasopharynx : It's boundaries are

Anteriorly, nasopharynx is limited by the internal nares and the posterior border of nasal septum.

Roof & the posterior wall of nasopharynx abut against the basilar part of the occipital bone. The lateral wall of the nasopharynx houses the pharyngotymphanic tube.

The floor of the nasopharynx is formed by the soft palate.

Oropharynx : It's boundaries are

Anteriorly by the tonsillar pillars.

Roofed by the soft palate (inferior aspect).

The inferior border is formed by the dorsal part of the tongue.

The superior border by the the epiglottis.

Laryngopharynx : It's boundaries are

Superiorly by the superior border of epiglottis. Inferiorly by the cricoid cartilage.

Posterior wall by middle & inferior constrictor muscles, stylopharyngeus and palatopharyngeus

muscles.

The posterior wall extends from the lower border of the 2nd

cervical vertebra above to the upper

border of the 6th

cervical vertebra below, where the laryngopharynx becomes continuous with the

oesophagus.

The laryngopharynx opens anteriorly into the larynx.



4/30


LARYNX :

The larynx lies at the level of the 4th

to 6th

cervical vertebrae.

It subserves two main functions :

1. Acts as a protective valve at the upper end of the trachea.

2. Acts as an organ of speech.

It is composed of a framework of cartilages interconnected by muscles and ligaments.

Cartilages of the larynx : ( No. of cartilages 9 )

Unpaired cartilages are :

Thyroid cartilage ,

Cricoid cartilage,

Epiglottis.

Paired cartilages are :

Arytenoid cartilages,

Corniculate cartilages,

Cuneiform cartilages.

Thyroid cartilage :

It is shield shape,

It consists of two laminae joined in midline.

The cartilagenous protrusion of the thyroid cartilage at the front of the neck is called

"Adam's apple".

Cricoid cartilage :

It forms a complete cartilagenous ring immediately below the thyroid cartilage.

It articulates with the thyroid cartilage and the arytenoids. Epiglottis :

It is a fibrous cartilage attached to the back of the thyroid cartilage on its lower side and to

the back of the hyoid bone on its upper side.

It projects backwards and upwards behind the base of the tongue, partially covering the inlet

of the larynx.

Arytenoid cartilages :

Pyramidal in shape.

They sit on each side of the upper lateral border of the cricoid cartilage.

Muscles of the larynx : They are of two types

External laryngeal muscles which are depressors of the larynx are :

Sterno thyroid ,

Thyro hyoid,

Inferior constrictor muscle.

Omohyoid is the external laryngeal muscle which is an elevator of larynx.

Intrinsic laryngeal muscles : they include

Cricothyroid muslce tensor of the vocal cords.

Lateral cricoarytenoid muslce abductor of the vocal cords.



5/30


Posterior cricoarytenoid muscle adductor of the vocal cords.

Inter-arytenoid muscle adductor of the vocal cords.

Thyro-arytenoid muscle relaxes the vocal cords.

False vocal cords are the vestibular folds which are narrow bands of fibrous tissue extending from

the anterolateral surface of each arytenid to the angle of the thyroid.

Rima glottidis is the narrow space between false vocal cords.

Glottis is the triangular opening formed by the true vocal cords.

Glottis is the narrowest part of the larynx in the adults.

Subglottis is the narrowest part of the larynx in neonates, infants and children.

True vocal cords are pale white ligamentous structures attached to the angle of the thyroid cartilage

and to the arytenoids.

Innervation of the larynx :

Internal branch of the Superior Laryngeal Nerve sensory supply to

epiglottis,

base of the tongue,

supraglottic mucous,

thyroepiglottic joint,

cricothyroid joint.

External branch of the Superior Laryngeal Nerve

Sensory to the anterior subglottic mucosa.

Motor to Cricothyroid muscle. Recurrent laryngeal nerve

Sensory innervation to larynx below the glottis.

Motor to all intrinsic laryngeal muscles except cricothyroid.

TRACHEA :

It is a tubular structure, lying opposite the 6th

cervical vertebra at the level of cricoid cartilage.

It is flattened posteriorly.

It is supported along its 10 to 15cm length by 16 to 20 horseshoe shaped or C shaped cartilagenous

rings.

It extends from the lower end of cricoid cartilage to the carina.

Carina is situated at T6 level.

According to the rule of thumb, the diameter of the trachea is similar to that of the patient's index

finger.

BRONCHI :

The trachea bifurcates at the carina to form the right and left main bronchi.

The right main bronchus is shorter and wider than the left main bronchus.

The right main bronchus descends at a steeper angle of 25 to the vertical compared with 45 on the

left side.



6/30


The right upper lobe branch arises at 2 3 cm from the carina.

Due to vertical angle of the right main bronchus, aspiration of the foreign body is most commonly

diverted to the right bronchus.

2. Define difficult airway ?

DIFFICULT MASK VENTILATION :

"Inability of the anaesthesiologist to maintain 90% saturation using 100% oxygen with

face mask in a patient with normal respiratory function "

DIFFICULT INTUBATION :

"A conventionally trained anesthesiologist failed to intubate for atleast three consecutive

attempts or taken a time period of more than 5 minutes to intubate "

DIFFICULT LARYNGOSCOPY :

"Inability to expose the glottis with a standard curved blade laryngoscope corresponding

to grade 3 & 4 of the Cormack and Lehane classification "

3. Discuss the airway compromising congenital conditions?

CONGENITAL DISEASE CLINICAL FEATURES

Pierre-Robin syndrome Micrognathia, Macroglossia,

Cleft soft palate

Treacher-Collins syndrome Auricular & ocular defects,

Malar & mandibular hypoplasia

Goldenhars syndrome Auricular & ocular defects,

Malar & mandibular hypolasia

Downs syndrome Poorly developed or absent bridge of the nose,

Macroglossia

Kippel-Feil syndrome

Congenital fusion of a variable number of cervical

vertebrae,

Restriction of neck movement

Goiter Compression of trachea,

Deviation of larynx/trachea



7/30


4. What are the acquired causes for airway compromise ?

ACQUIRED DISEASE FEATURES

Supraglottis Laryngeal oedema

Croup Laryngela oedema

Intraoral & Retropharyngeal abscess Distortion of the airway & trismus

Ludwig's angina Distortion of the airway & trismus

Rheumatoid arthritis TMJ Ankylosis,

Cricoarytenoid arthritis,

Deviation of larynx,

Restricted mobility of cervical spine.

Ankylosing spondylitis Ankylosis of cervical spine,

Ankylosis of TMJ,

Lack of mobility of cervical spine.

Cystic hygroma,

Lipoma,

Adenoma,

Goitre

Stenosis or distortion of the airway,

Fixation of the larynx,

Fibrosis from irradiation

Malignant tumor,

Facial injury,

Cervical spine injury,

Laryngeal or tracheal trauma.

Edema of the airway,

Hematoma,

Unstable fractures of the cervical spine.

Obesity Short thick neck,

Redundant tissue in the oropharynx,

Sleep apnea.

Acromegaly Macroglossia,

Prognathism

Acute burns Oedema of the airway.

5. What physical examination to be done to rule out difficult airway ?

A global assessment ( includes general, physical and regional examination ) should include :

1. Patency of the nares : look for masses inside nasal cavity (e.g. Polyps), deviated nasal septum, etc.

2. Mouth opening of at least 2 large finger breadths between upper and lower incisors in adults is

desirable.

3. Teeth :

Prominent upper incisors or canines can impose a limitation on alignment of oral or pharyngeal

axes during laryngoscopy,



8/30


A large base of tongue can cause difficulty during the direct laryngoscopy or bag-mask

ventilation.

An edentulous state, on the other hand, can render axis alignment easier but hypopharyngeal

obstruction by the tongue can occur.

4. Palate : A high arched palate or a long, narrow mouth may present difficulty.

5. Assess patients ability to protrude the lower jaw beyond the upper incisors (Prognathism).

6. Temporo-mandibular joint movement : It can be restricted in ankylosis/fibrosis, tumors, etc.

7. Measurement ofsubmental space (hyomental / thyromental length should ideally be > 6 cm).

8. Observation ofpatients neck : A short, thick neck is often associated with difficult intubation.

Any masses in neck, extension of neck, neck mobility and ability to assume sniffing position

should be observed.

9. Presence ofhoarse voice / stridor or previous tracheostomy may suggest stenosis.

10. Any systemic or congenital disease requiring special attention during airway management

(e.g. respiratory failure, significant coronary artery disease, acromegaly, etc.).

11. General assessment of body habitus can yield important information.

12. Infections of airway (e.g. epiglottitis, abscess, croup, bronchitis, pneumonia).

13. Physiologic conditions : Pregnancy and obesity.

6. What factors leads to difficulty in mask ventilation ?[ Pneumonic BONES )

The specific factors leading to difficulty in mask ventilation are :

1. Presence of Beard : It causes difficulty in creating proper seal with a mask.

2. Obesity : Patients with BMI > 26 kg/m2

may be difficult to mask ventilate,

3. No teeth: Difficult to establish effective seal,

4. Elderly and Snoring : Patients older than 55 years with a history of snoring are probably associated

with varying degrees of obstructive sleep apnea and are difficult to mask ventilate,

5. Jewellery worn by piercing of lips, tongue, cheek, chin, eye brows and ear may also create

difficulty in mask ventilation.

7. What are the specific tests for assessing airway ?

Basing on the anatomical criteria :

1. MALLAMPATTI TEST :

The Mallampatti test correlates tongue size to pharyngeal size.

Procedure :

The patient should be in the sitting position with head in a neutral position,

Ask the patient to open the mouth as widely as possible and protrude the tongue

maximally.

The patient should not be actively encouraged to phonate as it can result in contraction

and elevation of the soft palate leading to a spurious picture.

Classified into 3 classes, based on the extent the base of tongue that is able to mask the visibility

of pharyngeal structures.



9/30


MALLAMPATTI CLASS STRUCTURES SEEN

Class I

Soft palate,

Uvula,

Faucial pillars, Posterior pharyngeal wall

Class II

Soft palate,

Base of the Uvula,

Upper part of faucial pillars.

Class III Soft palate.

Class IV Only hard palate

Class IV is the modification of Mallampatti classification by Samsoon & Young's Modification.

2. ATLANTO OCCIPITAL JOINT ( AO ) EXTENSION :

It assesses the alignment of oral, pharyngeal and laryngeal axis in Sniffing or Magill's position.

Procedure :

The patient is asked to hold head erect, facing directly to the front,

Then he is asked to extend the head maximally.

The examiner should estimate the angle traversed by the occlusal surface of upper teeth.

Measurement can be by simple visual estimate or more accurately with a goniometer.

The normal angle of extension is 35 or more.

Grading is based on the angle of extension.

GRADE ANGLE OF EXTENSION

Grade I > 35

Grade II 22 -- 34

Grade III 12 -- 22

Grade IV < 12

3. MANDIBULAR SPACE :

Thyro mental distance ( PATIL'S TEST ):

Defined as " the distance from the mentum to the thyroid notch while the patient's

neck is fully extended ".

This measurement helps in determining how readily the laryngeal axis will fall in line

with the pharyngeal axis when the atlanto occipital joint is extended.

Normal thyromental distance is > 6.5cm.

If the thyromental distance is < 6cm, difficult airway is anticipated.



10/30


Sterno mental distance ( SAVVA'S TEST ):

Defined as " the distance from the suprasternal notch to the mentum with the

patient head fully extended on the neck with the mouth closed ".

Normal sterno mental distance is > 12cm.

A value of < 12cm, predicts a difficult airway.

Mandibulo hyoid distance :

Defined as " Measurement of mandibular length from chin (mental) to hyoid ".

Normal mandibulo hyoid distance is 4cm or three finger breadths.

Laryngoscopy becomes more difficult as the vertical distance between the mandible and

hyoid bone increases.

Inter incisor distance :

Defined as " the distance between the upper & lower incisors ".

Normal distance is 4.6cm or more / 3 fingers breadth.

< 3.8cm predicts difficult airway.

4. WILSON'S SCORE :

Wilson et al included five features to predict difficult airway. The maximum score is 10.

CLINICAL FEATURE CHARACTERISTICS SCORE

WEIGHT

< 90 Kg 0

90 110 Kg 1

> 110 Kg 2

RECEDING MANDIBLE

Normal 0

Moderate 1

Severe 2

JAW MOVEMENT

Interincisor Gap > 5 & Subluxation > 0 0

Interincisor Gap < 5 & Subluxation = 0 1

Interincisor Gap < 5 & Subluxation < 0 2

HEAD & NECK

MOVEMENT

> 90 0

90 10 1

< 90 2

BUCK TEETH

Normal 0

Moderate 1

Severe 2



11/30


5. JAW SLIDE TEST :

In this test, the patient is asked to protrude the lower jaw. The grading is given basing on the

relationship between the upper jaw & lower jaw.

GRADE CHARACTERISTICS

Grade A Lower teeth infront of the upper teeth

Grade B Lower teeth at the level of upper teeth

Grade C Lower teeth behind upper teeth

Grade C indicates difficult intubation

6. LEMON LAW'S ASSESSMENT :

Lemon represents 5 simple, reproducible and rapid assessment methods on unco-operative and co-

operative patients. L = Look externally to identify features suggesting difficulty.

Facial trauma, Large incisors, Beard or moustache, Large tongue.

E = Evaluate the 3-3-2 rule.

Inter incisor distance or mouth opening 3 fingers breadth.

Mento Hyoid distance 3 fingers breadth.

Distance between top of thyroid cartilage & mandible 2 fingers breadth.

M = Mallampati grade.

O = Obstruction ( presence of any condition like epiglottitis, peritonsillar abscess,

trauma ).

N =Neck mobility ( limited neck mobility )

The score with a maximum of 10 points is calculated by assigning 1 point for each of the above

LEMON criteria.

Difficult intubation is associated with higher LEMON scores.

7. CORMACK & LEHANE'S CLASSIFICATION :

It is based on Direct Laryngoscopic view of the airway.

The 4 grades based on the direct laryngoscopic views are :

GRADES STRUCTURES VISUALIZED

Grade I Entire laryngeal aperture

Grade II Only posterior commissure

Grade III Only epiglottis

Grade IV Soft palate

Grades III & IV predict difficult intubation.



12/30


8. UPPER LIP BITE TEST ( by KHAN et al 2002 ):

Here the patient is asked to bite the upper lip with the lower incisors.

The test is classified into three classes :

CLASS UPPER LIP BITE

Class I The patient is able to bite the upper lip above the vermilion line.

Class II The patient is able to bite the upper lip below the vermilion line.

Class III The patient cannot bite the upper lip.

Class III indicates difficult intubation.

9. RADIO-GRAPHIC ASSESSMENT : ( From Skeletal films )

Lateral cervical x-ray film of the patients with head in neutral position & mouth closed is requiredfor the following measurement:

1. Mandibulo-hyoid distance : An increase in the mandibulo-hyoid distance resulted in an

increase in difficult laryngoscopy.

2. Atlanto-occipital gap :

A-O gap is the major factor which limits the extension of head on neck.

Longer the A-O gap, more space is available for mobility of head at that joint with good

axis for laryngoscopy and intubation.

3. Relation of mandibular angle and hyoid bone with cervical vertebra and laryngoscopy

grading :

A definite increase in difficult laryngoscopy was observed when the mandibular angle

tended to be more rostral and hyoid bone to be more caudal.



13/30


4. Anterior/Posterior depth of the mandible : by White and Kander (1975)

Posterior depth of the mandible is the distance between the bony alveolus immediately

behind the 3rd

molar tooth and the lower border of the mandible.

It is an important measure in determining the ease or difficulty of laryngoscopy.

10. PREDICTORS OF DIFFICULT AIRWAY IN DIABETICS :

a) Palm print sign :

The patient is made to sit, palm and fingers of right hand are painted with blue ink.

The patient then presses the hand firmly against a white paper placed on a hard surface.

It is categorized as:

GRADE PALM PRINT SEEN

Grade 0 All the pharyngeal areas are visible.

Grade 1 Deficiency in the interphalangeal areas of the 4th

& 5th

digits.

Grade 2 Deficiency in the interphalangeal areas of the 2nd

to 5th

digits.

Grade 3 Only the tips of digits are seen.

b) Prayer sign :

Patient is asked to bring both the palms together as Namaste.

The sign is categorized as

Positive When there is gap between palms.

Negative When there is no gap between palms.

8. What are the alternative approaches to endotracheal intubation ?

Currently, there are several options available for the management of anticipated or unexpected difficult

endotracheal intubation. The options include the following :

1. Flexible fiberoptic intubation.

2. Intubating laryngeal mask airway assisted intubation.

3. Lightwand [Trachlight] aided intubation.

4. Indirect fiberoptic laryngoscope aided intubation [Bullard laryngoscope , Upsher Scope].

5. Gum elastic bougie aided intubation.

6. Retrograde intubation.

9. What is Lightwand [Trach light TM] aided intubation ?

In this technique, endotracheal intubation is done by transillumination of the soft tissues of the neck

using a lightwand.

It is a semi blind technique.

It is gaining popularity because the lightwand is lightweight, relatively inexpensive, can be used in

pre hospital setting and can be handled easily with minimum practice.

Most commonly employed lightwand is the TrachlightTM.



14/30


The Trachlight [TL] consists of 3 parts:

A reusable handle , A flexible wand & A stiff retractable stylet.

Reusable handle :

The handle is made up of plastic with a lid at one end, which lodges 3 triple A alkaline

batteries.

A locking clamp is located on the front of the handle, which accepts and secures a standard ETT

connector.

Flexible wand :

The lightwand consists of a flexible plastic shaft with a bright bulb affixed at the distal end.

The lightwands are reusable up to ten times and will accommodate tracheal tubes from Internal

diameter [ID] size 2.5-10 mm.

The bulb provides illumination of the soft tissues of the neck during intubation using the TL.

The light emitted by the TL is extremely bright with minimal heat production [a maximum

surface temperature of approximately 60C].

After 30 seconds of illumination, the light bulb blinks off & on to further minimize heat

production and also indicates 30 seconds of apnea time.

Affixed to the proximal end of the wand is a rigid plastic connector, which allows adjustment of

the wand along the handle and accomodates the endotracheal tube of varying length.

Retractable stylet:

Enclosed within the lightwand is a stiff, but malleable, retractable stylet.

The retractable stylet gives sufficient stiffness to the device, allowing the wand to be shaped in a

field-hockey stick or J-shaped configuration. The shape enhances manoeuverability during intubation and facilitates the placement of the ETT

into the glottic opening.

Technique : One needs to prepare the endotracheal tube Trachlight [ETT-TL] assembly prior to use.

First, the stiff internal stylet of the light wand is lubricated with water soluble KY jelly or silicone

fluid ensuring its easy retraction during intubation.

Water soluble lubricant is now applied over the wand to facilitate the removal of the wand

following ETT placement.

The length of the wand is now adjusted by sliding the wand along the handle, placing the light bulb

at the end of the ETT without protruding beyond its tip.

Now the ETT-TL unit is bent to a 90 angle just proximal to the cuff of the tube in the shape of a

field-hockey stick configuration for orotracheal intubation and " J ," shaped configuration for

nasotracheal intubation.

With the anaesthetized patient lying supine and head in sniffing position, the jaw is grasped and

lifted upward using the thumb and index finger of the intubators nondominant hand.

The preshaped ETT-TL unit is now inserted into the midline of the oropharynx using the dominant

hand.

The midline position of the ETT-TL is maintained while the device is advanced gently in a rocking

motion along an imaginary midline sagittal arc. When resistance is felt, the ETT-TL is rotated



15/30


backward and the tip redirected towards the thyroid prominence using the glow of the light as a

guide.

When the tip of the ETT-TL enters the glottic opening, a well-defined circumscribed glow is seen in

the anterior neck slightly below the thyroid prominence. At this point, the stiff internal stylet is

retracted approximately 10 cms.

This makes the wand with premounted ETT pliable, allowing advancement into the trachea. The

ETT-TL is then advanced until the glow starts to disappear at the sternal notch.

Following release of the locking clamp, the TL is removed from the ETT.

Advantages of Trachlight :

1. TL aided ETI is an easy technique, relatively easy to learn and requires less experience.

2. Relatively inexpensive.

3. The lightwand is reusable for 10 times.

4. TL is used as an aid in the placement of an ETT or in the positioning of an already placed ETT.

5. TL is a useful adjunct in difficult airway.

6. It does not require extensive neck manipulation and can be used in patients with potential cervical

spine instability.

7. It is useful in patients with poor or irregular dentition and in patients with limited mouth opening.

8. It is less traumatic than blind nasal intubation.

9. It may be applied after failed intubation using rigid laryngoscopy.

10. Presence of secretion or blood is of no consequence while using the instrument.

Disadvantags of Trachlight :1. It is not recommended in patients with laryngeal inflammatory disorders such as epiglotitis or

tracheal stenosis.

2. It should not be used in patients with foreign body in the airway.

3. It is not recommended in patient with laryngeal or tracheal abnormalities such as polyps, tumors, or

a retropharyngeal abscess.

4. In morbidly obese patients, the ability to see the glow may be diminished.

5. On the contrary, in thin or frail patients, some trans-illumination may occur even when the tube tip is

in the esophagus.

10. Describe indirect fiberoptic laryngoscope aided entotracheal intubation ?

The indirect fiberoptic laryngoscope aided entotracheal intubation is done with the following :

1. Bullard Laryngoscope.

2. Upsher scope.

BULLARD LARYNGOSCOPE :

It is a rigid, fiberoptic intubating laryngoscope for indirect oral laryngoscopy, transmitting the view

from the tip of the L-shaped blade to a proximal view finder.

It is a valuable aid for the management of the predicted as well as the unanticipated difficult tracheal

intubation.

When using the Bullard laryngoscope, the oral, pharyngeal, and tracheal axes do not have to be



16/30


aligned to view the larynx. So it is the instrument of choice in the emergency trauma situation for

patients with suspected injury to the cervical spine.

Description of the Bullard Laryngoscope :

It is a curved rigid fiberoptic intubation device.

It consists of a conventional laryngoscope battery handle with light source and a unique anatomically

shaped blade.

The laryngoscope has fiberoptic bundles for both airway illumination and transmission of the view

from the distal tip to the proximally located eyepiece.

There is provision for the attachment of conventional video endoscope camera.

A 3.7 mm working channel is incorporated into the laryngoscope which permits

suctioning / administration of oxygen / administration of local anesthetics.

The proximal end of the working channel is provided with a Luer-lock connector for the attachment

of a three-way stopcock, so that all the above mentioned 3 functions can be done with a flick of the

knob.

The scope is provided with a tip extender which facilitates the lifting of the epiglottis.

It is also provided with a detachable metal stylet for mounting the ETT.

Bullard Laryngoscope comes in 3 sizes:

1. Pediatric [ newborn to 2 years ]: It has the following dimensions

width - 1.3 cm,

thickness - 0.64 cm,

internal radius of curvature - 0.74 inch.

2. Pediatric long [newborn to 10 years].3. Adult: It has the following dimensions

width - 2.5 cm,

thickness - 0.64 cm,

internal radius of curvature - 1.32 inch.

Technique : Select an appropriate size Bullard Laryngoscope.

Attach the blade extender to the device if it is to be used in large adults.

The blade extender provides sufficient length to pick up the epiglottis.

Load the chosen ETT over the stylet. Lubricate the blade and the handle.

The scope is held in the left hand. The blade-stylet assembly with premounted ETT is inserted into

the mouth in the horizontal plane, over the top of the tongue, and then swung caudad in the sagittal

plane into the posterior pharynx. The device follows the natural curve of the oropharynx.

As the scope ETT assembly is advanced, epiglottis is visualized. It is then picked up and lifted

anteriorly.

On visualizing the glottic opening, advance the ETT off the stylet into the trachea.

UPSHER SCOPE :

It is a steel C-shaped laryngoscope with an integrated fiberoptic system.

It consists of a C-shaped metal blade of fixed curve.



17/30


It has a light channel and viewing fiberoptic bundle running along the entire length of the curved

blade.

It is equipped with a focusing ring on the eyepiece.

The tube channel of the scope is loaded with a 6.5 8.5 mm ID endotracheal tube.

Technique : After adequate anesthesia, the patients head and neck is positioned neutral.

The Upsher scope is inserted following the oropharyngeal curve and is made to slide down the back

of the tongue until the epiglottis is visualized.

At this stage the tongue of the patient is pulled out of the mouth or is asked to be protruded.

The epiglottis is now loaded onto the Upsher Scope tip with a scooping motion.

The scope is now elevated in an anterior direction elevating the epiglottis and exposing the glottic

aperture.

After having visualized the vocal cords, the pre-loaded ETT is advanced through the glottic opening

under vision.

The ETT is now disengaged from the channel, and the scope is withdrawn.

11. Describe the " gum elastic bougie aided intubation " ( GEBI )?

Gum elastic bougie aided intubation [GEBI] may be used blindly or aided by indirect laryngoscopy

with a laryngeal mirror / laryngeal mask airway.

Currently, two types of Gum Elastic Bougies ( GEB ) are available :

Straight GEB basically a tube changer.

Angled GEB recommended for endotracheal intubation in difficult airway situations.

The angled GEB

It has a length of 60 cm and a diameter 15 French.

It has an angulation at its distal end approximately 5 cm from its tip.

The angulation permits the tip to be steered around obstacles when the GEBs shaft is

rotated.

The angulation also assists the GEB to be manoeuvered blindly underneath the posterior

surface of the epiglottis in patients with Cormack Lehanes grade 3.

The tip looses its angulation after a maximum of 5 attempts at tracheal intubation.

The straight GEB It has a length of 70 cm and a diameter of 15 French.

It is not recommended during difficult airway manoeuvers.

It is used as a tube exchanger.

Technique : GEB is used in a number of ways to assist difficult intubation. They are as follows:

While performing left handed direct laryngoscopy in patients with grade III or IV Cormack and

Lehanes view, the anesthesiologist passes the 15 French 60 cm-long GEB blindly under the

epiglottis with his right hand. The GEB is considered to be correctly introduced intratracheally if the

anesthesiologist feels a click sensation as the tip of the GEB slides over the tracheal cartilage and/or

feels a resistance at 20-40 cm as the tip of the GEB hits the carina or a small bronchus. After



18/30


eliciting one or both of these vital signs, the ETT is slid over the bougie into the trachea and its

correct position is confirmed with capnography and auscultation of the chest.

If one is using indirect laryngoscopy with a laryngeal mirror, an appropriate size laryngeal mirror is

introduced with the left hand while an assistant gives a good jaw thrust. The operator now focuses

his head light on the mirror and tries to visualize the laryngeal structures. With his right hand the

operator passes the GEB into the trachea via the glottis. Subsequently, the ETT is rail-roaded into the

trachea over the GEB and confirmed for its correct position by auscultation and capnography.

Bougie aided intubation via the LMA : In this method, after the LMA has been noted to be in

correct position, a GEB is passed into the trachea and the operator feels for the clicks or resistance.

The LMA is now deflated and removed and the ETT is railroaded over the stylet or the bougie into

trachea. One can improve the success rate of this method by keeping the bougie in the midline and

angling the distal tip of the bougie anteriorly, if not present. Once the laryngeal vestibule is entered,

the bougie is rotated through 180. This facilitates the advancement of the bougie down the patients

trachea.

12. Describe " Retrograde Intubation "?

Retrograde intubation was first reported by D. J. Waters in 1963.

Retrograde intubation is a two stage procedure.

1st

stage retrograde passage of a catheter or a long guide wire from the larynx to the mouth or nose.

2nd

stage consists of railroading an ETT over the guide wire or the catheter.

The essential equipment for retrograde intubation consists of

an 16 18G IV cannula/catheter over needle,

a 18G epidural catheter or a J-tipped vascular guide wire , 70cm in length.

An artery forceps to prevent holding of the catheter or guide wire.

Technique :

The skin infront of the neck is infiltrated with 1 2ml of 1% lignocaine.

The larynx is stabilized between the thumb and the index finger of one hand.

The cricothyroid membrane is punctured with the catheter over needle assembly held at 45 pointing

cephalad.

After confirmation of tracheal placement of IV catheter by the aspiration of free air, catheter over

needle assembly is pushed further at an obtuse angle closer to the axis of the larynx. The needle stylet is now withdrawn.

A J-tipped guide wire or epidural catheter is inserted through the IV catheter and advanced cephalad

into the oro/nasopharynx.

The guide-wire or the epidural catheter is readily retrieved from the mouth using a Magill forceps if

patient fails to deliver it spontaneously.

The other end of the catheter or the wire infront of the neck, at the level of the cricothyroid

membrane, is held by the artery forceps so that it may not slip inside.

The catheter or the wire is now inserted into an appropriate size ETT and it is pulled to make it taut.

The tip of the ETT is well lubricated so as so facilitate its entry into the glottic opening.

In case of awake intubation, the patient is now asked to protrude his tongue. ( If the patient has been



19/30


anaesthetized, an assistant gently pulls the tongue forwards ).

This maneuver elevates the epiglottis and provides a clear passage of the ETT into the glottis.

As the ETT enters the larynx, resistance is felt at the level of the cricothyroid membrane.

At this stage the catheter is relaxed so as to relieve the tension at its distal end. This permits the

gentle advancement of the ETT into the trachea.

Following confirmation of the intra-tracheal placement of the ETT by auscultation over chest and

capnography, the catheter or the wire is removed through the mouth.

Complications of retrograde intubation :

peritracheal hematoma / tracheal laceration / infection [including soft-tissue neck infection]

subcutaneous emphysema / pneumothorax / pneumomediastinum,

mediastinitis and trigeminal nerve trauma / injury to the larynx and vocal apparatus,

recurrent laryngeal nerve damage.

Advantages of retrograde intubation :

Ideal for patients wiht cervical spine fractures where C-spine motion is to be avoided.

It is a safe alternative strategy in anticipated difficult airway.

It is effective in cases of failed intubation where bag-mask ventilation is adequate and time is

available.

Disadvantages of retrograde intubation :

It is not used in patients with infected skin of the neck.

It is not recommended in patients with infectious or neoplastic laryngeal lesions.

13. How is the airway anesthetized for " awake or conscious " intubation ?

Anesthesia of the Nares :

Done by cotton pledgets soaked in a mixed solution containing 4% Lignocaine & 1% Phenylephrine

( 3 : 1 combination which yields 3% Lignocaine & 0.25% Phenylephrine ) or a 4% Cocaine solution

(1.5 mg/kg ).

It can also be done by inserting large-sized soft nasal airways coated with 2% Lignocaine ointment.

These drugs anesthetize the mucous membrane of the nose, accompanied by vasoconstriction to

widen the nasal passages & decrease the bleeding.

Anesthesia of the Nasopharynx :

The anesthetic solution is instilled through a 16G or 18G plastic catheter inserted deeply into the

nose.

By slowly applying long cotton tipped applicators till they reach the posterior wall of the

nasopharynx.

If three such applicators can be inserted, a 7.0-mm ID endotracheal tube will usually pass through

that nostril.



20/30


Anesthesia of the Oropharynx :

The tongue and oropharynx can be anesthetized with 10% Lignocaine spray using the laryngoscope

blade or a tongue depressor.

The patient can also gargle and expectorate 30 ml of 2% viscous lignocaine solution to produce

topical anesthesia of the pharynx.

Anesthesia of the Trachea :

The trachea can be anesthetized with a translaryngeal application of 2 to 3ml of 1% Lignocaine.

A 22G catheter or a 23G needle is inserted through the cricothyroid membrane in the midline, air is

aspirated to confirm the location of the needle tip.

2ml of 1% lignocaine is injected quickly at the end of expiration & the needle is removed

immediately.

The cough induced by stimulation of the laryngeal mucosa, provides excellent spread of the

anesthetic below the vocal cords.

Nerve blocks to anesthetize the airway :

1. Glossopharyngeal Nerve Block :

Glossopharyngeal nerve provides sensation to the posterior 1/3rd

of the tongue, the pharynx and

the superior surface of the epiglottis.

A 22G spinal needle is used to inject 5mL of 1% lidocaine with epinephrine into the

base of each posterior tonsillar pillar.

The needle should be aspirated to avoid intravascular injections.

The block is acceptable with a full stomach and does not appear to affect airway integrity whenperformed bilaterally.

The block is intended to provide more comfortable laryngoscopy.

2. Superior Laryngeal Nerve ( SLN ) Block:

SLN innervates the epiglottis, aryepiglottic folds, and the laryngeal structures down to the false

cords.

The patient is placed supine with the neck extended.

The hyoid bone is displaced laterally toward the side to be blocked, and a 25G, 2.5cm needle is

walked off the greater cornu of the hyoid bone inferiorly and is advanced 2 to 3 mm. As the needle passes through the thyrohyoid membrane, a slight loss of resistance is felt, and 3 mL

of 1% lignocaine solution is injected superficial and deep to this structure. The block is then repeated

on the opposite side. This technique produces anesthesia from the inferior aspect of the epiglottis to

the vocal cords.

The SLN may also be blocked by the application of lidocaine-soaked pledgets with Krause forceps

held in the pyriform fossa. This technique is frequently performed by otolaryngologists prior to

laryngoscopy.



21/30


13. Describe the "flexible fiberoptic intubation"?

Fiberoptic intubation was first performed by Dr. P. Murphy in 1967.

Flexible fiberoptic bronchoscopy is useful for the anesthesiologist in the following :

management of difficult tracheal intubation, evaluation of the upper airway,

verification of ETT placement,

repositioning or checking patency of ETT,

changing ETT,

placement of double lumen tubes,

placement of endobronchial blockers.

Principle of fiberoptics :

Fiberoptic bronchoscopy depends on the mechanics of light.

Light travels at different velocities in different substances. The velocity of light in a substance

depends on the refractive index of the substance.

The refractive index of a substance is the ratio of velocity of light through the substance and the

velocity of light through a vaccum.

The difference in light velocities alters the direction of a light beam as it passes from one medium to

another.

If the light hits a glass air interface at 90, it passes straight through the substance. As the angle of

incidence of the light is increased from the perpendicular, the greater the bending of light as it

emerges from the glass into the air.

Total internal reflection ( i.e., the light is reflected back inside the glass ) occurs at a critical angle.

The fiberoptic scope is a flexible instrument, capable of transmitting an image from the distal tip to

the proximal end.

The technological factor of fiberscope is that when a beam of light enters an ordinary glass rod, it is

reflected off the walls of the rod and emerges from the other end.

The glass rod becomes flexible ( called glass fiber ) when the diameter of the glass rod is < 25 .

The light enters at one end of the glass fiber and is repeatedly reflected off the walls of the fiber and

emerges at the other end with a uniform appearance. A single fiber is capable of transmitting light

but not capable of transmitting an image.

For image transmission, an objective lens is placed at the tip of the fiberscope. This lens focuses the

image on a large number of flexible fibers, which are tightly fastened together at the proximal and

distal ends of the scope.

The image which emerges at the handle of the fiberscope is focussed by the eyepiece lenses and can

be viewed directly by the operator or can be transmitted with a video camera to a television screen

and / or video recorder.

To prevent degradation of the image, each fiber is coated with a transparent substance of lower

refractive index. This process is called Cladding.

The image resolution is directly related to the size of the smallest fibers ( the lower limit for glass



22/30


fiber size is 8, images smaller than this cannot be resolved )

The quality of the image is

directly proportional to the total no. of glass fibers in the coherent bundle and

indirectly proportional to diameter of the glass fiber.

The fiberscope is composed of three parts :

Body of the scope includes the tip deflection unit, eye piece, focussing light & working

channel sleeve.

Aflexible insertion cord contains a working channel, one image transmitting fiber bundle &

one or two light transmitting bundles.

A light transmission cord sends light from an external source to the tip of the insertion cord

which allws the field of view to be illuminated.

Steps of Fiberscope intubation :

Premedicate the patient . ( Inj. Glycopyrrolate 0.2 0.4 mg, Inj. Fentanyl 2g/kg or Inj. Midazolam

1 2 mg ). ( anticholinergic is strongly recommended to prevent secretions from obscuring the view

in the upper airway )

The tip of the fiberscope is defogged with a commercial solution or warm soapy water.

The fiberscope is lightly lubricated along its entire length with a water soluble agent ( K-Y Jelly )

to facilitate passage through the ETT.bro

Anesthetize the airway ( Total dose of lignocaine is 3mg/kg )

Pre-oxygenate the patient with 100% oxygen for 3 mins.

For conscious, sedated nasal intubation, the lubricated ETT is inserted into the posterior nasopharynx& the fiberscope is passed through it. In anesthetized patients, a standard oral airway is used to keep

the tongue off the posterior pharyngeal wall.

For consious or anesthetized oral intubation, the epiglottis is the major obstacle for directing the tip

of the fiberscope. An intubating airway or a bite block is inserted, then ETT is inserted about 8 to

10cm into the airway and the fiberscope is passed through the ETT.

Keep the insertion cord of the fiberscope straight and taut & do not form a loop ( this improves the

control over the tip of the scope )

Oxygenate through the working channel while performing the procedure.

Push the fiberscope very slowly and gently while entering the oropharynx ( either oral / nasal route )

Identify the 1st

landmark, ' epiglottis '.

Advance the fiberscope to the laryngeal opening, and advance further until it enters the subglottic

space.

Identify the 2nd

landmark, ' trachea '.

Advance further till the 3rd

landmark, ' carina ' is seen.

Now advance the ETT, with a gentle rotation motion.

Remove the fiberscope, verify the position of ETT and connect to the breathing circuit.



23/30


Problems encountered during fiberoptic intubation :

1. Poor vision due to poorly focussed eye piece / film over the lens / fogging / secretions & blood.

2. Bleeding

3. Coughing

4. Laryngospasm & bronchospasm

5. Oesophageal intubation

6. Failure to railroad the ETT.

7. Desaturation due to

respiratory depression due to drugs

excessive use of suction

endobronchial intubation

Cleaning & Disinfection of Fiberscope :

Immediately after use, the suction channel should be rinsed with water or saline to remove blood,

tissue and secretions.

Outside of the fiberscope is wiped with detergent solution.

The channels of the fiberscope should be brushed with detergent solution to prevent drying of

secretions.

The fiberscope is dried by wiping with dry guage.

Additional items of equipment like cameras, remote video controllers, light sources and procedure

carts should be wiped with 70% alcobol.

2% alkaline glutaraldehyde is the disinfectant of choice for flexible endoscopes and should be

immersed for a minimum of 20min.

The disinfection should be followed by adequate rinsing of the instruments with sterile deionized

water to remove all traces of the disinfectant.

The insertion tube , the channels and the suction valve rinsed with 70% alcohol and then dried.

Gas sterilization with ethylene oxide at temperatures < 55C for 10 -12hrs is safe.

14. Describe "Blind nasal intubation " ?

The blind nasal intubation is done in either awake or asleep without visualizing the larynx.

Indications for blind nasal intubation :

Potentially difficult orotracheal intubation. Patients in whom muscle relaxants & surgical airway are contraindicated.

Patients with dental fractures, arthritis or dislocations of TMJ.

Patients with small mouth, a short neck, a large tongue, a H/O of previous head and neck

surgery or cervical spine immobility.

Contraindications for blind nasal intubation :

acute epiglottitis,

apnoea,

basilar skull fractures with or without CSF rhinorrhoea,



24/30


bleeding diathesis,

upper airway foreign body,

large bilateral nasal polyps, abscesses and severe laryngeal trauma.

Technique :

The patient is premedicated with anticholinergic ( Inj. Glycopyrrolate 0.2mg / Inj. Atropine 0.6mg )

Opioid analgesics ( Inj.Fentanyl 50g ) or Benzodiazepines ( Midazolam 1 2mg ) given to provide

mild sedation, analgesia and reduction of cough and bronchospasm.

Advantage of Fentanyl is that it is rapidly reversed by Naloxone.

Airway is anesthetized with lignocaine ( total dose should not exceed 3mg/kg )

Vasoconstriction of nasal mucosa is accomplanished with a topical solution of Oxymetazoline or

Phenylephrine.

The ETT is lubricated with xylocaine jelly.

The right nostril is preferred for passage of ETT because the bevel of the ETT will face the flat

nasal septum, reducing damage to the turbinates.

A 6 6.5mm ID ETT for women & 7 7.5mm ID ETT for men are suitable for nasotracheal route.

Insertion to a depth of 26cm, measured at the naris in women and 28cm in men , results in proper

placement of the tube within the trachea.

The ETT is advanced in a direction perpendicular to the face and paralled to the hard palate.

Once the endotracheal tube has passed into the nasopharynx, the monitoring of breath sounds

becomes the key for successful intubation.

At each inspiratory effort, the tube should be advanced while constantly monitoring breath sounds.

If advancing the tube results in loss of or reduction in breath sounds ( indicates esophageal

intubation ) , then the tube should be withdrawn to the point at which the breath sounds aremaximally heard. The endotracheal tube then turned slightly and readvanced with each inspiratory

effort.

If on repeated insertions, the ETT failed to enter the trachea, the tube should be withdrawn to the

point where the breath sounds are heard loudest. Then the cuff is inflated with 10ml of air. This

directs the ETT tip anteriorly away from the posterior pharyngeal wall.

Then the tube is advanced a further 2cm without loss of breath sounds. When the tube is near the

laryngeal inlet, the patients starts to cough, at this point, the cuff is deflated and the tube is advanced

further into the trachea.

During this process to facilitate entry of ETT into the trachea, the patient's neck is extended or

cricoid pressure is applied to align the tube with the glottis.

Successful intubation is confirmed by auscultation of the chest for breath sounds and with the help

of capnography.

15. Describe " Rapid sequence induction " ?

The rapid sequence induction is also known as " CRASH INDUCTION".

It is the universally accepted way of securing the airway for a patient who has a full stomach.

Technique :

The patient is preoxygenated with 100% oxygen for a minimum of 3 minutes with a tight

fitting face mask.



25/30


The calculated IV dose of Inj. Thiopentone ( 5 6 mg/kg ) is rapidly administered

intravenously followed immediately by Inj. Succinylcholine ( 2 mg/kg ) or Inj. Rocuronium

( 1.2 mg/kg ).

After administration of the muscle relaxant, positive pressure ventilation is not done.

Cricoid pressure is applied ( SELLICK'S MANEUVER ) starting from the induction of

anesthesia till the confirmation of correct placement of the ETT.

Cricoid pressure acts as a barrier to regurgitation of gastric contents during induction of

anesthesia and prevents inflation of the stomach during positive pressure ventilation.

The thumb and middle finger are placed on either side of the cricoid to prevent lateral

movement of the cartilagenous ring and backward pressure ( upto 30 Newtons ) is applied.

This compresses the oesophagus against the vertebral column and occludes it leaving the

airway patent.

If active vomiting occurs during application of cricoid pressure, it should be abandoned to

prevent rupture of oesophagus.

16. How do you assess the cervical spinal stability in trauma cases prior to airway

manoeuvers ?

The 5 clinical criteria, that are used to clear cervical spine stability in conscious trauma patients :

1. No posterior midline cervical spine tenderness,

2. No intoxication,

3. An alert patient,

4. No focal neurological deficits and

5. No painful distracting injuries.

The overall sensitivity of the above criteria is 97.6% and having low specificity.

The conscious patients who do not satisfy the above criteria must be investigated by three cervical

radiographs namely

lateral view including the base of the occiput to 1st

thoracic vertebra,

anteroposterior view

open mouth odontoid view to rule out injury to the cervical spine.

The above views identify 61% of cervical injuries.

In patients with altered mental status, the cervical spine injury is ruled out by lateral radiograph of

the neck. CT scanning has higher sensitivity of 97 100%.

MRI investigation of choice to detect spinal cord injury.

17. Describe ' Cricothyrotomy ' ?

It is a life saving procedure and final option of " Cannot ventilate & Cannot intubate " situations.

In infants and children, cricothyrotomy is difficult to perform because of soft cartilages and ill defined

cricothyroid membrane.



26/30


Indications for Cricothyrotomy :

1. Failure of oral or nasal endotracheal intubation ( causes )

Massive oral, nasal, or pharyngeal hemorrhage

Massive regurgitation or emesis

Masseter spasm

Clenched teeth

Structural deformities of oropharynx, congenital or acquired

Stenosis of upper airway (pharynx or larynx)

Laryngospasm

Mass effect (cancer, tumor, polyp, web, or other mass)

2. Airway obstruction (partial or complete)

Nontraumatic

Oropharyngeal edema

Laryngospasm

Mass effect (cancer, tumor, polyp, web, or other mass)

Traumatic

Oropharyngeal edema

Foreign body obstruction

Laryngospasm

Obstruction secondary to a mass effect or displacement

Stenosis

3. Traumatic injuries making oral or nasal endotracheal intubation difficult

Maxillofacial injuries Cervical spine instability

4. Need for definitive airway during procedures on face, neck, or upper airway

Laryngeal surgery

Oral surgery

Maxillofacial surgery

Laser surgery

Bronchoscopy

Contraindications for cricothyrotomy :

1. Absolute contraindications :

Endotracheal intubation can be accomplished easily and quickly, and no contraindications to

endotracheal intubation are present.

Transection of trachea with retraction of distal end into the mediastinum.

Fractured larynx or significant damage to the cricoid cartilage or larynx

2. Relative contraindications :

For infants and toddlers (


27/30


Technique of Cricothyrotomy :

If there are no contraindications, such as known or suspected cervical spine injury, thepatient's head

should be hyperextended. Extension of the neck aids identification of the anatomy and control of the

cricoid space.

Cricothyroid membrane is identified.

The skin and subcutaneous tissue immediately above the cricothyroid membrane is infiltrated using

lidocaine with epinephrine.

The larynx is stabilized by holding it between the nondominant thumb and middle finger.

A 20 to 22G needle is inserted through the cricothyroid membrane to confirm intra-airway

positioning by aspirating air. The needle is kept in position to serve as a guide for the surgical

procedure and removed before insertion of the tracheostomy tube.

A midline longitudinal (vertical) skin incision about 3 to 4 cm long over the cricoid membrane is

made for an emergency cricothyrotomy. For an elective cricothyrotomy, a 2 cm transverse

(horizontal) skin incision is made.

After the skin incision, a short horizontal (transverse) stabbing incision about 1 cm long is made in

the lower part of the cricothyroid membrane (i.e., nearer the cricoid cartilage than the thyroid

cartilage to avoid the cricothyroid arteries).

The stabbed incision is widened with the Curved Mayo scissors or a curved hemostat or blunt end of

the scalpel or a tracheal dilator.

The tracheostomy tube is inserted between the tracheal dilator blades or hemostat, the cuff is inflated

and correct placement of the tube is confirmed by auscultation of breath sounds and by

capnography..

Complications of surgical cricothyrotomy :

Immediate / Early complications Late / Delayed complications

Bleeding, hematoma

Incorrect tube placement

Unsuccessful tube placement

Prolonged procedure time

Subcutaneous emphysema

Obstruction of the tube

Esophageal & Mediastinal perforation

Pneumothorax, pneumomediastinum

Vocal cord injury

Laryngeal fracture

Aspiration

Obstructive problems

Voice changes or dysphonia

Infections

Bleeding

Persistent stoma

Subjective feeling of lump in the throat

Subglottic or glottic stenosis

Tracheoesophageal fistula

Tracheomalacia

Types of Cricothyrotomy :

1. Needle cricothyrotomy : performed with catheters i.e., from 4cm length in children upto 14cm

length in adults.



28/30


2. Percutaneous dilatational cricothyrotomy : performed using Seldinger technique.

3. Surgical cricothyrotomy : performed by making incision through the cricothyroid membrane using

a scalpel after which an ETT is inserted.

18. Describe " Transtracheal Jet Ventilation " ( TTJV ) ?

TTJV is the percutaneous insertion of a catheter into the trachea through cricothyroid membrane and

ventilation achieved using jet ventilation.

The pressure of the gas used for jet ventilation in adults is 50 psi and in children is 30 psi.

TTJV is employed as an emergency airway.

In infants and children less than 5 yrs of age it is not recommended because of high incidence of :

vasovagal events,

subcutaneous emphysema,

bilateral pneumothorax, inadvertent placement into oesophagus and submucosal false passage in trachea.

In infants and children cricoid and thyroid carriages are soft and cricothyroid membrane is poorly

defined. So successful placement of catheter into infant trachea is difficult.

Major limitation of TTJV is the need to maintain patent airway cephalic to the catheter. If upper

airway is obstructed, life threatening barotrauma occurs.

Technique :

The landmarks are similar to cricothyrotomy.

A 5-mL syringe containing 1 to 2 mL of sterile normal saline or water or 1% lignocaine is attached

to a large-bore needle (13 or 14G).

With the thumb and middle fingers of the nondominant hand, the cricoid cartilage is stabilized, and

the cricothyroid membrane is palpated with the index finger. The syringe is held in the dominant

hand and the needle is directed caudally at


29/30


Complications of TTJV :

Common complications Rare complications

Subcutaneous emphysema (mostcommon)

Kinking of the catheter

Blockage or obstruction of the catheter

Coughing (in a conscious patient)

Bleeding (minor), hematoma

Infections

Aspiration

Incorrect or unsuccessful catheter

placement Prolonged procedure time

Persistent stoma

Subjective feeling of a "lump in the

throat"

Pneumatocele

Barotrauma Pneumothorax

Pneumomediastinum

Mediastinal perforation

Esophageal perforation

Dysphonia or voice changes

(secondary to vocal cord injury,

laryngeal fracture, or disruption of

laryngeal cartilage)

Subglottic/glottic stenosis Tracheoesophageal fistula

Damage to laryngotracheal mucosa

Swallowing problems

19. What are the differences between adult & paediatric airways ?

Infants have small nares and nasal passages.

In infants head is large compared to body size resulting in automatic sniffing position withoutelevation of occiput.

Infants have a large tongue in relation to oral cavity. Base of tongue is situated in close proximity to

laryngeal inlet. This caudal insertion is called glossoptosis.

Tonsils are small in newborn but it grows to maximal size at 4 7 years of age. Enlarged tonsils may

obscure laryngeal view or may interfere with mask ventilation.

In infants epiglottis lies at the level of C1 ( in adults C3 ) touching the soft palate separating

oesophageal inlet from laryngeal inlet. Hence infants are obligate nasal breathers till 2 6 months of

age, the ability to breath orally is age related and increases with postnatal age.

The epiglottis in infants is large, stiff and omega shaped. ( in adults, it is short broad & flat ).

Epiglottis is attached at 45 to anterior pharyngeal wall in infants and children( in adults at 20 ). As

a result, epiglottis should be picked up with the laryngoscopic blade for better visualization of

glottis.

Larynx lies in a more cephalic position C3 C4 at birth, C4 C5 at 2 years and C5 C6 in adults.

A cephalic and superior position of larynx in infants creates more acute angulation between glottis

and base of tongue, hence posterior displacement is often necessary to improve the view.

Larynx is funnel shaped till 68 years of age. ( in adults cylindrical in shape )

Cricoid cartilage is the narrowest part of the airway in infants. (glottis in adults)

The vocal cords are bow shaped making an angle with anterior commissure, where as the plane of

vocal cords is perpendicular to long axis of trachea and vocal cords are linear in adults.



30/30


Trachea in infants is short narrow and angled posteriorly resulting in accidental endobronchial

intubation or extubation with changes in head position.

Ribs are horizontal with decreased anterior, posterior and cephalic movements. Hence the diaphragm

is the mainstay of ventilation in neonates.

The angle formed by abdominal wall and diaphragm is more acute in infants, which reduces the

mechanical efficiency during contraction.

Infants have higher percentage of type II fibres (fast twitch, low oxidative) in their respiratory

musculature leading to early appearance of respiratory fatigue.

20. What are the different techniques for difficult airway management ?

The techniques for Difficult Airway Management

Techniques of Difficult Intubation Techniques for Difficult Ventilation

Alternative laryngoscope blades Awake intubation

Blind intubation

Fiberoptic intubation

Intubating stylet or Tube changer

LMA

Light wand

Retrograde intubation

Invasive airway access

Esophageal tracheal Combitube Intratracheal jet stylet

Laryngeal mask airway

Oral and nasopharyngeal airways

Rigid ventilating bronchoscope

Invasive airway access

Transtracheal jet ventilation

Two-person mask ventilation

References :

1. Practice of Anesthesia Churchillson & Wylie - 7th

Edition.

2. Miller's anesthesia 6th

Edition

3. Anesthesiology Yao & Artusio's - 4th

Edition4. Indian Journal of Anesthesia . Volume 45, August 2005

Documents

Airway Discussion