AA Course-Difficult Airway1

7/23/2019 AA Course-Difficult Airway1

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Difficult Airway Management

Anesthesia Assistant Course

Algonquin College

Joel Berube

19 SEP 09



Objectives

Airway management is our specialty!

Significant M&M associated with mismanaged

airwaysAvoidance: Anticipate

Airway exam, predictors of difficulties

Preparation Know your equipment

Back-up plan Methods, adjuncts for intubation/ventilation/oxygenation



Outline

The Difficult AirwayDefinitions

AssessmentThe AlgorithmAnticipated DA

Unanticipated DA

DevicesFibreoptic Bronch

GlidescopeBullard Scope

Jet Ventilator

Surgical AirwaysPercutaneous Trach

Cricothyroidotomy

Trans-tracheal Jet



The “Difficult Airway” Definitions

Difficult Airway

Difficult

Laryngoscopy

Difficult Mask

Ventilation

DifficultEndotracheal

Intubation



Difficult Airway

Situation where a “conventionally trained

anesthesiologist” experiences difficulty

with mask ventilation, endotracheal

intubation or both



Difficult Mask Ventilation

1 person unable to keep SpO2 >92%

Significant gas leak around face mask

No chest movement

Two-handed mask ventilation needed

Change of operator requiredUse of fresh gas flow button >2X (flush)



Predictors of Difficult Ventilation

BeardHiding? Bad seal

ObesityBMI > 26

Age>55

TeethLack of…

Snoring

On history or dx OSA

BOATS



Difficult Laryngoscopy

Not possible to view any part of the vocal

cords during direct laryngoscopy

Cormac-Lehane Grades III/IV



Difficult Endotracheal Intubation

Insertion of ETT with direct laryngoscopy

requires >3 attempts or >10 minutes

Or when an experienced laryngoscopistusing direct laryngoscopy requires:More than 2 attempts with same blade

Change in blade or use of adjunctUse of alternative device/techniquefollowing failed intubation with directlaryngoscope



Predictors of Difficult

Laryngoscopy/Intubationaka: your airway assessment (last class)

Mallampati

What can you see when they open their mouth?Mouth Opening, teeth Can you fit your blade + tube in the opening?

Thyromental Distance Predicts an “anterior larynx”

C-Spine Range of Motion Can they get in a “sniffing position”?



Tough Airways?



General Approach to Airways:

Is Airway Control Required?ie: is there a different anesthetic technique?

Predict Difficult Laryngoscopy?

Is Supralaryngeal Ventilation (LMA, mask) okto use if needed?

ie: can you get away without intubation?

Full Stomach?

Will the patient tolerate an apneic period?



Difficult Airway Algorithm

A model for the approach to the difficult

airway

Considers:Patient factors

Clinical setting

Skills of the practitioner

If you need to intubate the patient for the

case and run into trouble at any step…





Airway assessment

Non-ReassuringLaryngoscopy

Ventilation techniqueAspiration Risk

Intolerance of apnea

Anticipated DAAwake Technique

Box A

NB - “Invasive” = knife

or needle in the neck

(see “surgical airway”)

ReassuringPut the patient to

sleep, now havingdifficulty

Unanticipated DAAttempts after

inductionBox B



Difficult Airway Algorithm -

Anticipated DA



DA anticipated, intubate Awake:

Patient will maintain their

own patent airway

Can abandon or tryanother approach

No “bridges burned”

Concept: freeze the

airway, put the tube in,

+/- sedation (usually +!)



Awake Intubation Advantages:

Maintain spontaneous ventilation

Wide open pharynx and palate space

Forward tongue

Maintain esophageal tone (aspiration) Able to protect if reflux occurs

Risk of neurologic injury: able to monitorsensory-motor function Some spines: awake intubation + positioning!



Contraindications to Awake

Emergency: no ABSOLUTE, but caution

Cardiac ischemia, bronchospasm,

increased ICP or ocular pressure

Elective:

Refusal or inability to cooperate

Child, mental retardation, dementia, intox

Allergy to local anesthetics



Technique:

Generally “Awake Intubation” implies use

of Fibreoptic Bronchoscope

Any other method to intubate is possible,

but likely more difficult or tough to

tolerateUsed to do awake blind nasal intubations intrauma patients (some still do)



The Fibreoptic Bronchoscope

“fragile device with optical and non-optical elements” Glass-fibre bundle (10k-30k fibres)

Objective - Insertion Cord - Eyepiece ~60cm, graduated q10cm

Flexible, rotate, bend, control

Working Channel (2mm diam) Suction, O2, fluids, drugs

Peds intubating scopes: no channel (<2mm ext diam)

Light Source



Bronch



FOB intubation:

BronchCorrect size

Light Sourcemonitor/eyepiece

Suction

O2 for patient

Tube/Lube

Oral Airways/Bite block

Local Anesthetic3 areas to freeze

Nasopharynx

Base of tongue

Larynx/trachea

TopicalSwish/swallow

Pledgets

Viscous

Nebulized4% Lido, 10-15minpre

Nerve Blocks



FOB intubation

Topicalize the airwaySupplemental O2

Appropriate sedationFor the patient!

Insert Oral AirwayAppropriate size… it willhelp guide scope andprotect it

Tube loaded on scopeHolder/tape

suction

Visualize cords withscopeSome more local viaworking channel?

Advance ETT

Confirm placement

ETCO2

Induce the anestheticVery uncomfortable

Patient needs coaching/reassurance throughout!!!



Troubleshooting

FOB not good if pt. bleeding inA/W or ++ secretionsSuction not adequate

Try O2 to clear lens Desaturations…

Keep O2 on!

Breaks for patient

Sedation level

Fogging upDefogger

Warm scope prior to starting

Suction/insuffl/flush

Adjust picture?

Tube not advancing

through cordsToo large tube and toosmall scope: the extra room

causes the tube to catch onarytenoids

Softer ETT

Deep breath

Scope in centre of cords,bevel forward, rotate ETTclockwise



Pearls:



DA Algorithm

Ok, so if you’re not reassured by the airway, intubateawake If not successful (box A)

Cancel/wake vs. invasive airway!!

What if the airway doesn’t look bad and you bangthe patient off to sleep only to see this…

Obviously you can’t just stick

the tube in! What now?





From this point on, consider:

Call for Help

Absolutely!

Return to Spontaneous Ventilation

If you can

Awakening the patient

If you can



Cannot Intubate Scenario

Optimize position/scope etc…

DO NOT persist with repeated attempts

at direct laryngoscopyEvidence that this approach leads tocomplications (including death)

Return to Mask Ventilation, get SpO2back up and try another techniqueGlidescope, Bullard, Bougie, Trachlite,Intubating LMA, McCoy Blade…





Alternate Techniques

Your first attempt at laryngoscopy should always be setup to be the best

Early transition from one technique to another without

persistent and multiple failed attemptsOn subsequent attempts, use adjuncts to enhancewhatever’s missing the last time

Need to remain fluid/flexible and adapt the plan as you

progress through the algorithm Often means going through lots of equipment

Having backups and backups for the backups



Other devices

Reviewed last week?

Different laryngoscope bladesMAC, Miller, McCoy

Different introducers

Stylet, Bougie, Trachlite

“Supraglottic Devices”

LMA, Proseal, Fastrach (ILMA)

Combitube, King Airway, Cobra Airway



Glidescope

Video-assisted

laryngoscopy

Video chip set at the endof a “conventional-like”blade

Steeper angle (60º)

Canadian Invention!



Glidescope Advantages

Setup minimal/easy!

Handled with similar skills

for direct laryngoscopyBut in midline

No need to elevate tongue

Point of sight is near

blade tipCan see around thecorner”

Image on screenSupervisor, assistantcan see too

Less stress on

airway

Don’t need external

light sourceLightweight, compact



Glidescope Negatives

As with FOB, image can be obscured by

blood/secretion Less a problem with color vs. B/W monitor

Sometimes view is better than you can get a tube into Variations on stylet bends

Re-usable glidescope stylet

Limited number of handles/blades Need to be sterilized between uses

Cap in correct place before cleaning!!!



Bullard Scope

Fixed fibreoptic cable on

posterior part of bladeSame setup as FOB

Eyepiece

Working Channel

Detachable StyletBlade has “natural curve” Good if C-spine ROM

Pedecesso to lidesco"e?



Bullard +’s

Low profileGets into mouth when opening limited

High Flow O2 via channel blows secretionsaway and may reduce fogging

Attached stylet helps direct tube to glottis

Can use standard scope handle instead oflight source



Bullard -’s

Finnicky… sometimes very difficult to get

a good view, even in an easy airway

Plastic extension on blade sometimes

dislodges. Don’t forget it in the patient!!!



Back to the Difficult Airway

Still unable to intubate despite help, various

adjuncts, adjustments, alternate devices…

Now you’re having trouble ventilating!!!Now try: 2 and 3 handed mask ventilation,

LMA (if feasible)If this works, get the SpO2 back up, breatheyourself… Try again, abort, discuss





Cannot Intubate-Cannot Ventilate

THIS IS AN EMERGENCY

If you haven’t yet… CALL FOR HELP

People die if you can’t ventilate them

You NEED to secure an airway or have the

patient awake and breathing on their own!

Securing the airway likely now = Invasive Airway

Salvage techniques while getting the surgicalairway?



The “Surgical” Airway

aka the invasive airway

If access to the airway through the mouth or

nose is unavailable, need to access the

airway via the trachea

Needle cricothyroidotomy and jet ventilation

Percutaneous cricothyroidotomy set

Emergency/Awake Tracheostomy



Cricothyroidotomy

Landmarks: thyroid cartilage,cricoid cartilage = cricothyroid

membraneLocal to skin (if time) and entryvia membrane with large needleattached to partially-filled syringe

Aspiration of air = into airway!

Proceed to ventilate, retrogradewire intubation, percutaneouscric set



Transtracheal “Ventilation”

Connect theneedle/angiocath to an

oxygen source, jetventilator, ambubag anddeliver air/oxygen intothe trachea

Not a protected ordefinitive airway

Life-saving, temporizingmeasure



Sanders Jet Ventilation

O2 from hi-pressure source

(50psi) thru valveand switch to aneedle and into

the airwayUsed in shared

airway surgeriesRigid bronch

Surgeon working in airway, can’t

use normal ventilation/ETT



Sanders Jet Ventilator

Continuous Ventilation is possible Can minimize apneic period, shorten surgery

Can deliver O2, N2O, Volatile Anesthetic Jet entrains room air, so variable and unpredictableFiO2 at end of scope

Inadequate ventilation of lungs if poor

compliance Difficult to assess adequacy of ventilation

Can be used for transtracheal oxygenation Next section



Percutaneous Cric Set

Once cricothyroid membrane

punctured with needle, can use

Seldinger technique to dilatetissues and insert a large bore

cannula to secure the airway Not a trach, but allows ventilation

and oxygenation with low-pressuresystems (std 15mm connector) Ambubag, conventional ventilator

Some are cuffed, so would

“protect” airway



Emergency Tracheostomy

Rather than needlingthe neck, once it’s

established that thepatient needs asurgical airway, thesurgeon performs a

surgical tracheostomy Awake or asleep,depending on whereon the algorithm thescenario happens to be



Awake Tracheostomy

Some airways are so non-reassuring and patientsso high risk that Plan A is to perform a tracheostomyunder local anesthetic (+/- minimal sedation) PRIOR

to any other airway management or anesthesia Ex: certain head/neck tumors/malformations,

Any attempt at awake intubation may create an A/Wobstruction and loss of airway Can’t intubate, can’t ventilate scenario is avoided!

Awake patient prepped and draped, surgerystarted… once airway access secured, induction ofanesthesia can occur





Recap

Difficult Airway Definitions Predictors

Difficult Airway Algorithm

Fibreoptic Bronchoscope Awake intubation

Alternate Devices Glide, Bullard, Sanders

Emergency Airway

Surgical Airway



Take-Home messages

Not all airways are routineThere’s more to a difficult airway than difficultlaryngoscopy

Need skills with various airway tools and adjuncts andmust transition between them easily and quickly

Familiarity with the difficult airway algorithm shouldgive you a sense of which direction a given scenario

is takingWhen faced with cannot intubate, cannot ventilatescenario, decision to secure surgical airway is life-

saving and hesitation can be costly



Questions? Discussion?

Thank you.

Documents

AA Course-Difficult Airway1