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
airways
 Avoidance:
 Anticipate
 Airway exam, predictors of difficulties
 Preparation
 Know your equipment
 Back-up plan
 Methods, adjuncts for intubation/ventilation/oxygenation
Outline
 The Difficult Airway
Definitions
Assessment
 The Algorithm
Anticipated DA
Unanticipated DA
 Devices
Fibreoptic Bronch
Glidescope
Bullard Scope
Jet Ventilator
 Surgical Airways
Percutaneous Trach
Cricothyroidotomy
Trans-tracheal Jet
The “Difficult Airway” Definitions
 Difficult Airway
 Difficult
Laryngoscopy
 Difficult Mask
Ventilation
 Difficult
Endotracheal
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 required
Use of fresh gas flow button >2X (flush)
Predictors of Difficult Ventilation
 Beard
Hiding? Bad seal
 Obesity
BMI > 26
 Age
>55
 Teeth
Lack of…
BOATS
 Snoring
On history or dx OSA
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 laryngoscopist
using direct laryngoscopy requires:
 More than 2 attempts with same blade
 Change in blade or use of adjunct
 Use of alternative device/technique
following failed intubation with direct
laryngoscope
Predictors of Difficult
Laryngoscopy/Intubation
 aka: 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) ok
to 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-Reassuring
Laryngoscopy
Ventilation technique
Aspiration Risk
Intolerance of apnea
 Anticipated DA
Awake Technique
Box A
NB - “Invasive” = knife
or needle in the neck
(see “surgical airway”)
 Reassuring
Put the patient to
sleep, now having
difficulty
 Unanticipated DA
Attempts after
induction
Box B
Difficult Airway Algorithm Anticipated DA
DA anticipated, intubate Awake:
Patient will maintain their
own patent airway
Can abandon or try
another 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 monitor
sensory-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
tolerate
 Used to do awake blind nasal intubations in
trauma 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:
 Local Anesthetic
 Bronch
Correct size
 Light Source
 monitor/eyepiece
 Suction
 O2 for patient
3 areas to freeze
Nasopharynx
Base of tongue
Larynx/trachea
Topical
Swish/swallow
Pledgets
Viscous
 Tube/Lube
Nebulized
 Oral Airways/Bite block
Nerve Blocks
4% Lido, 10-15min pre
FOB intubation
 Topicalize the airway
Supplemental O2
 Appropriate sedation
For the patient!
 Insert Oral Airway
Appropriate size… it will
help guide scope and
protect it
 Tube loaded on scope
 Visualize cords with
scope
Some more local via
working channel?
 Advance ETT
 Confirm placement
ETCO2
 Induce the anesthetic
Very uncomfortable
Holder/tape
suction
Patient needs coaching/reassurance throughout!!!
Troubleshooting
 FOB not good if pt. bleeding in  Tube not advancing
A/W or ++ secretions
through cords
Suction not adequate
Try O2 to clear lens
 Desaturations…
Keep O2 on!
Breaks for patient
Sedation level
 Fogging up
Defogger
Warm scope prior to starting
Suction/insuffl/flush
Adjust picture?
Too large tube and too
small scope: the extra room
causes the tube to catch on
arytenoids
Softer ETT
Deep breath
Scope in centre of cords,
bevel forward, rotate ETT
clockwise
Pearls:
DA Algorithm
 Ok, so if you’re not reassured by the airway,
intubate awake
 If not successful (box A)
 Cancel/wake vs. invasive airway!!
 What if the airway doesn’t look bad and you
bang the 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 laryngoscopy
 Evidence that this approach leads to
complications (including death)
Return to Mask Ventilation, get SpO2
back up and try another technique
 Glidescope, Bullard, Bougie, Trachlite,
Intubating LMA, McCoy Blade…
Alternate Techniques
 Your first attempt at laryngoscopy should
always be set up to be the best
 Early transition from one technique to another
without persistent and multiple failed attempts
 On subsequent attempts, use adjuncts to
enhance whatever’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 blades
 MAC, 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 end
of a “conventional-like”
blade
 Steeper angle (60º)
Canadian Invention!
Glidescope Advantages
 Setup minimal/easy!
 Handled with similar
skills for direct
laryngoscopy
But in midline
No need to elevate tongue
 Point of sight is near
blade tip
Can see around the corner”
 Image on screen
Supervisor, assistant
can see too
 Less stress on
airway
 Don’t need external
light source
Lightweight, 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 blade
 Same setup as FOB
 Eyepiece
 Working Channel
 Detachable Stylet
 Blade has “natural curve”
 Good if C-spine ROM 
Predecessor to Glidescope?
Bullard +’s
Low profile
 Gets into mouth when opening limited
High Flow O2 via channel blows secretions
away and may reduce fogging
Attached stylet helps direct tube to glottis
Can use standard scope handle instead of
light 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, breathe
yourself… 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 surgical
airway?
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
membrane
 Local to skin (if time) and entry
via membrane with large needle
attached to partially-filled syringe
 Aspiration of air = into airway!
 Proceed to ventilate, retrograde
wire intubation, percutaneous
cric set
Transtracheal “Ventilation”
 Connect the
needle/angiocath to an
oxygen source, jet
ventilator, ambubag and
deliver air/oxygen into
the trachea
 Not a protected or
definitive airway
 Life-saving, temporizing
measure
Sanders Jet Ventilation
O2 from hipressure source
(50psi) thru valve
and switch to a
needle and into
the airway
Used in shared
airway surgeries
 Rigid 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 unpredictable
FiO2 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 dilate
tissues and insert a large bore
cannula to secure the airway
 Not a trach, but allows ventilation
and oxygenation with low-pressure
systems (std 15mm connector)
 Ambubag, conventional ventilator
 Some are cuffed, so would
“protect” airway
Emergency Tracheostomy
 Rather than needling
the neck, once it’s
established that the
patient needs a
surgical airway, the
surgeon performs a
surgical tracheostomy
 Awake or asleep,
depending on where
on the algorithm the
scenario happens to
be
Awake Tracheostomy
 Some airways are so non-reassuring and
patients so high risk that Plan A is to perform a
tracheostomy under 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/W obstruction and loss of airway
 Can’t intubate, can’t ventilate scenario is avoided!
 Awake patient prepped and draped, surgery
started… once airway access secured,
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 routine
 There’s more to a difficult airway than difficult
laryngoscopy
 Need skills with various airway tools and adjuncts and
must transition between them easily and quickly
 Familiarity with the difficult airway algorithm should
give you a sense of which direction a given scenario
is taking
 When faced with cannot intubate, cannot ventilate
scenario, decision to secure surgical airway is lifesaving and hesitation can be costly
Questions? Discussion?
Thank you.