7. Difficult Airway
Situation where a “conventionally trained
anesthesiologist” experiences difficulty
with mask ventilation, endotracheal
intubation or both
1/25/2024
8. 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)
1/25/2024
9. Predictors of Difficult Ventilation
Beard
Hiding? Bad seal
Obesity
BMI > 26
Age
>55
Teeth
Lack of…
Snoring
On history or dx OSA
BOATS
1/25/2024
11. 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
1/25/2024
12. Predictors of Difficult
Laryngoscopy/Intubation
Your airway assessment .
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”?
1/25/2024
14. 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?
1/25/2024
15. 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…
1/25/2024
17. 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
1/25/2024
19. 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 +!)
1/25/2024
20. 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!
1/25/2024
21. 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
1/25/2024
22. 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)
1/25/2024
23. 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
1/25/2024
25. FOB intubation:
Bronch
Correct size
Light Source
monitor/eyepiece
Suction
O2 for patient
Tube/Lube
Oral Airways/Bite block
Local Anesthetic
3 areas to freeze
Nasopharynx
Base of tongue
Larynx/trachea
Topical
Swish/swallow
Pledgets
Viscous
Nebulized
4% Lido, 10-15min pre
Nerve Blocks
1/25/2024
26. 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
Holder/tape
suction
Visualize cords with
scope
Some more local via
working channel?
Advance ETT
Confirm placement
ETCO2
Induce the anesthetic
Very uncomfortable
Patient needs coaching/reassurance throughout!!!
1/25/2024
27. Troubleshooting
FOB not good if pt. bleeding in
A/W or ++ secretions
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?
Tube not advancing
through cords
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
1/25/2024
29. DA Algorithm
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?
1/25/2024
31. From this point on, consider:
Call for Help
Absolutely!
Return to Spontaneous Ventilation
If you can
Awakening the patient
If you can
1/25/2024
32. 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…
1/25/2024
34. 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
1/25/2024
37. 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
1/25/2024
38. 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!!!
1/25/2024
39. 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?
1/25/2024
40. 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
1/25/2024
41. 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!!!
1/25/2024
42. 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
1/25/2024
44. 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?
1/25/2024
45. The “Surgical” Airway
The same is 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
1/25/2024
46. 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
1/25/2024
47. 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
1/25/2024
48. Sanders Jet Ventilation
O2 from hi-pressure
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
1/25/2024
49. 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
1/25/2024
50. 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
1/25/2024
51. 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
1/25/2024
52. 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, induction of anesthesia
can occur
1/25/2024
59. 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 life-
saving and hesitation can be costly
1/25/2024
