Dr.Gayathri RamanathanDr.Gayathri Ramanathan

Associate ProfessorAssociate Professor

SRM MEDICAL COLLEGE HOSPITAL & SRM MEDICAL COLLEGE HOSPITAL & RESEARCHCENTRERESEARCHCENTRE

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• Causes of difficult intubation • Basic airway evaluation• Management plan for Anticipated difficult airway – Plan A, Plan

B , Plan C & Plan D• Gallery of tools• The Expected & Unexpected Difficult Airway

OBJECTIVES

DEFINITION

American society of Anesthesiologist (ASA) suggested

(difficult to ventilate) That when sign of inadequate ventilation

could not be reversed by mask ventilation or

oxygen saturation could not be maintained above 90%

DEFINITION

(difficult to intubate) If a trained Anaesthetist using conventional

laryngoscope takes more than 3 attempts or

more than 10 minute to complete tracheal intubation

15- 50%

EVEN WITH

PROPER

EVALUATION !

ARE ONLY PICKED UP

DIFFICULT

MASK

VENTILATIO

N

DIFFICULT INTUBATION

EXTREMELY DIFFICULT

ABANDON

GS – 1 in 2000OBG- 1 in 300

CAUSES OF DIFFICULT INTUBATION

Anesthetist

Pre-op assessmentEquipments

Experience not enoughPoor technique

Malfunctioning equipment

Inexperienced assistance

CAUSES OF DIFFICULT INTUBATION

Patient

1. Congenital causes 2. Acquired causes

Basic airway evaluation in all patients

Dr. Binnion’s LEMON Law

BONES

The 4 D’s

Dr. Binnions Lemon Law: An easy way to remember multiple tests…

L ook externally.E valuate the 3-3-2 rule.M allampati.O bstruction?N eck mobility.

L: Look Externally

Receding jaw

Short muscular neck

ObesityBuck teeth

Dentures

L: Look Externally

Facial trauma

Stridor

Macroglossia

E:Evaluate the 3-3-2 rule

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3 fingers fit in mouth- Inter incisor distance

3 fingers fit from mentum

to hyoid cartilage 2 fingers fit from the floor

of the mouth to the top of the thyroid cartilage

M: Mallampati classification

Class-I Class-II

Class-III Class-IV

soft palate, fauces; uvula, anterior and the posterior pillars.

the soft palate, faucesand uvula

soft palate and base of uvulaOnly hard palate

O: Obstruction? BloodBlood

VomitusVomitus

Teeth Teeth

EpiglottisEpiglottis

DenturesDentures

TumorsTumors

Impacted ObjectsImpacted Objects

N:Neck mobility -Measurement of

Atlanto-Occipital Angle

Thyro- Mental Distance

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Measure from upper edge of thyroid cartilage to chin with the head fully extended.

• A short thyromental distance = an anterior larynx .

• > 7 cm is usually = easy intubation

• < 6 cm = difficult airway

MANAGEMENT PLAN OF

ANTICIPATED DIFFICULT AIRWAY

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Is mask ventilation going to be difficult?

Can’t ventilateDefined by “BONES”• Beard• Obesity• No teeth• Elderly• SnoringCan’t ventilate

Is laryngeal visualization going to be difficult?Can’t intubate

Defined by 4 D’s1.Disproportion2.Distortion3.Dysmobility4.Dentition

Disproportion

Pierre robin sequence

Acromegaly

Prognathism

Achondroplasia

Can’t intubate

Neurofibromatosis

Burns contracture

Distortion

Cystic hygroma

Can’t

intu

bate

DysmobilityTM joint Ankylosis

Klippel Fiel

Can’t

intubate

Edentulous

Buck teeth

Dentition

Can’t

intubate

Is cricothyroidotomy going to be difficult?

Can’t Rescue

Should assessment reveal a potentially difficult airway the cricothyroid membrane should be identified and marked, BEFORE an intervention is undertaken

Possible Options!Following airway assessment, the person performing the intubation should be in a position to decide between three possible

options1.Awake intubation2.Quick look3.Induction and paralysis

1. Awake Intubation

The patient needs to be intubated awake

There is significant risk of complications if sedatives and/or muscle relaxants are administered prior to airway control.

2. Quick Look

The patient may be sedated for an attempt at direct laryngoscopy WITHOUT muscle

relaxation (“Quick Look”)

There is some risk of failed laryngoscopy but

There should be a low risk of failed mask ventilation.

3. Induction & Paralysis

The patient may be induced and paralyzed,

In this case the patient is assessed as having a low risk of laryngoscopy and/or mask

ventilation 

Pre-oxygenation: How Much Is Enough?

Two techniques common in use:1. Tidal volume breathing (TVB) of oxygen

for 3–5 min2. Deep breaths (DB) 4 times within 0.5

min

Both are equally effective in increasing arterial oxygen tension (Pao2).

Anesth Analg 1981; 60: 313–5

Each subject received 5 mg/kg thiopental and 1 mg/kg succinylcholine.

Anesthesiology 2001, 95: 754-759

Spontaneous recovery from

succinylcholine-induced apnea

may not occur sufficiently

quickly to prevent hemoglobin

desaturation in subjects whose

ventilation is not assisted.

Pre-oxygenation

What are we going to do if we don’t get the Tube?

Plans “A”, “B” ,“C” and plan “D”.Know this answer before you tube.

Failure -Why does it happens?

No critical discussion with colleagues about proposed management plan

No request for experienced helpExaggerated idea of personal abilityIll-conceived plan A and/or plan BPoorly executed plan A and/or plan BPersisting with plan A too long, starting the rescue

plan too lateNot involving, and preparing, surgical colleagues

GALLERY OF TOOLS

ILMAVideo laryngoscopesMalleable video stillet- Levitan scopeFibreoptic bronchoscope

ELECTIVE EMERGENCY

Old case of Hemi-mandibulectomy with forehead flap with trismus for block dissection of neck nodes

ELECTIVE

Anesthesia of choice - G.A.

Intubating technique of choice

?

MANAGEMENT PLAN OF

UNANTICIPATED DIFFICULT AIRWAY

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TheUnexpected DifficultAirway

Experienced help may not be immediately available

Special equipment may not be immediately available

A general anaesthetic has usually been administered

A long acting relaxant may have been givenBackup airway management plans may be

poorly thought out

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Take home messageBe familiar with the alternative methods of

intubating technique and use it regularly in your day today practice e.g. ILMA, FOB, Videolaryngoscopes, cricothyroidotomy…………….

So that you won’t fumble at the time of crisis

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Challenges may Challenges may bebe

Waiting for youWaiting for you

Thank you