difficult airway and identification by dr vijaykumar silvaraja

1. AIRWAY ASSESSMENT AND
IDENTIFICATION OF DIFFICULT
AIRWAY
DR VIJAYKUMAR
SILVARAJA
EMERGENCY PHYSICIAN
HOSPITAL SELAYANG

2. DIFFICULT AIRWAY VS FAILED AIRWAY
IDENTIFICATION OF DIFFICULT AIRWAY
OUTLINE

3. DIFFICULT AIRWAY vs FAILED
AIRWAY

4. DEFINITION DIFFICULT AIRWAY
4
Difficult Airway- When a trained anaesthesiologist
experiences difficulty with mask ventilation, tracheal
intubation or both
Difficult ventilation-When it is not possible to maintain
SPO2>90% using 100% O2 and positive pressure mask
ventilation in a patient
Difficult Intubation-When a skilled person using direct
layngoscopy requires more than 3 attempts or more than
10 minutes
American Society of Anaesthesiologist 2003

5. DIFFICULT AIRWAY
Can be divided into two categories:
Anatomically Difficult Physiologically Difficult
• There are anatomical or logistical
barriers to successful airway
management.
• Requires anatomical assessment
of the airway to determine the
possibility of a difficult airway.
• Critically ill patients who are
physiologically compromised such as
unstable hemodynamics, impaired
oxygenation/ventilation and/or
metabolic derangement.
• Requires optimization of overall
patient management in context of
stabilization of physiological
parameters prior to intubation to
minimize risk of peri-intubation
arrest.
The Walls Manual of Emergency Airway Management, 5th ed

6. 6
Why Need To Predict Difficult Airway?

7. DEFINITION FAILED AIRWAY
• A failed airway exists when any of these conditions is met
1. Failure to maintain acceptable oxygen saturation during
or after one or more laryngoscopic attempts
2. Three failed attempts by an experienced intubator even if
oxygen saturation can be maintained
3. Single best attempt at intubation fails in “forced to act”
situation
The Walls Manual of Emergency Airway Management, 5th ed

8. Failed airway present in two ways:
1. Can’t Intubate, Can’t Oxygenate
2. Can’t Intubate, Can’t Oxygenate
DEFINITION FAILED AIRWAY
The Walls Manual of Emergency Airway Management, 5th ed

9. IDENTIFICATION DIFFICULT
AIRWAY

10. IDENTIFICATION DIFFICULT
AIRWAY
4 dimensions:
1. Difficult
laryngoscopy
2. Difficult BVM
3. Difficult EGD
4. Difficult
cricothyrotomy
The Walls Manual of Emergency Airway Management, 5th ed

11. IDENTIFICATION DIFFICULT AIRWAY
The Walls Manual of Emergency Airway Management, 5th ed
4 DIMENSIONS

12. 4 DIMENSIONS DIFFICULT
AIRWAY
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility
DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask seal/Mallampati/Male
A – Age
N – No teeth
DIFFICULT EGD
R – Restriction
O – Obstruction/Obesity
D – Disrupted/Distorted airway
S – Short thyromental distance
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour
The Walls Manual of Emergency Airway Management, 5th ed

13. L = Look
Externally
Eg: small mandible, large tongue, large teeth and
short neck
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility

14. E = Evaluate
3 – adequacy of oral access
3 - dimensions of the mandibular space to accommodate
the tongue on DL
2- location of the larynx in relation to the base of the tongue
Theoretically
use patient’s
finger
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility

15. M =
Mallampati
Score
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility

16. CORMACK LEHANE

17. O =
Obstruction
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility
-The presence of stridor is generally considered to indicate that the
airway has been reduced to <50% of its normal caliber, or to a
diameter of 4.5 mm or less !!!
- Obese patients frequently have poor glottic views by DL or VL

18. N = Neck
mobility
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility

19. R = Restriction/Radiation DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask seal/Mallampati/Male
A – Age
N – No teeth
Recent evidence suggests that radiation
treatment to the neck is one of the
strongest predictors of difficult and failed
mask ventilation.

20. O =
Obesity/OBSTR
UCTION/OSA
DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask seal/Mallampati/Male
A – Age
N – No teeth
PROBLEM IN OBESE:
- increased body mass and the resistance to diaphragmatic excursion
- redundant tissues, creating resistance to airflow in the upper airway
- frequently have poor glottic views by DL or VL
- desaturation faster

21. M = Mask
DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask seal/Mallampati/Male
A – Age
N – No teeth
Eg; Bushy beards, blood or debris on the face, or a disruption of lower facial
continuity

22. A = Age
DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask
seal/Mallampati/Male
A – Age
N – No teeth

23. N = No Teeth
DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask seal/Mallampati/Male
A – Age
N – No teeth
Tips:
- Leave dentures (if available) in situ for BMV and remove them for intubation.
- gauze dressings may be inserted into the cheek areas through the
mouth to puff them out in an attempt to improve the seal.
- Another technique for limiting mask leak involves rolling the lower lip down toward the chin
and using the inner mucosal surface as a contact point for the bottom of the mask

24. R = Restricted
Opening
DIFFICULT EGD
R – Restriction
O – Obstruction/Obesity
D – Disrupted/Distorted airway
S – Short thyromental distance
Adequate mouth opening is required for
insertion of the EGD

25. O = Obesity /
Obstruction
DIFFICULT EGD
R – Restriction
O – Obstruction/Obesity
D – Disrupted/Distorted airway
S – Short thyromental distance

26. D =
Distorted
Airway
DIFFICULT EGD
R – Restriction
O – Obstruction/Obesity
D – Disrupted/Distorted airway
S – Short thyromental distance
Eg: fixed flexion deformity of the spine, penetrating neck injury
with hematoma, epiglottitis, and pharyngeal abscess each may
distort the anatomy sufficiently to prevent proper positioning
of the device.

27. S = Short thyromental distance
DIFFICULT EGD
R – Restriction
O – Obstruction/Obesity
D – Disrupted/Distorted airway
S – Short thyromental distance

28. S = Surgery
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour
The anatomy may be subtly or obviously distorted, making the airway landmarks
difficult to identify. Scarring may fuse tissue planes
and make the procedure more difficult.

29. M = Mass
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour
A hematoma (postoperative or traumatic), abscess, or
any other mass in
the pathway of the cricothyrotomy may make the
procedure technically difficult,
and requires the operator to meticulously locate the
landmarks

30. A = Access /
Anatomy
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour
Obesity makes surgical access challenging, as it is often difficult
to identify landmarks. Similar challenges are presented by
subcutaneous
emphysema, soft tissue infection, or edema.

31. R = Radiation
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour
Past radiation therapy may distort and scar tissues

32. T = Tumor
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour

33. 4 DIMENSIONS DIFFICULT AIRWAY
DIFFICULT LARYNGOSCOPE
L – Look externally
E – Evaluate 3-3-2
M – Mallampati score
O – Obstruction/Obesity
N – Neck mobility
DIFFICULT BVM
R – Restriction/Radiation
O – Obstruction/Obesity/OSA
M – Mask seal/Mallampati/Male
A – Age
N – No teeth
DIFFICULT EGD
R – Restriction
O – Obstruction/Obesity
D – Disrupted/Distorted airway
S – Short thyromental distance
DIFFICULT CRICOTHYROTOMY
S – Surgery
M – Mass
A – Assess
R – Radiation
T - Tumour
The Walls Manual of Emergency Airway Management, 5th ed

34. OTHER PREDICTORS
Tintinalli 9th edition

35. OTHER PREDICTORS

36. Assess seven most common bedside tests, routinely used to detect difficult
airways. These take only a few seconds to complete and require no special
equipment.
1. Mallampati test (original or modified; asking a sitting patient to open his
mouth and to protrude the tongue as much as possible so that visibility can
be determined);
2. Wilson risk score (including patient's weight, head and neck movement,
jaw movement, receding chin, buck teeth);
3. Thyromental distance (length between the chin and the upper edge of
Adam's apple);
4. Sternomental distance (length between the chin and the notch between
the collar bones);
5. Mouth opening test;
6. Upper lip bite test;
7. or any combination of these tests.

37. Key results
•For difficult laryngoscopy 🡪upper lip bite
test had the highest sensitivity
•For difficult tube insertion 🡪 Modified
Mallampati test had the highest sensitivity

38. OTHER PREDICTORS
Upper lip bite test
In class 3, probability of a difficult intubation increases from 10% to >60% (+LR 14)
Will This Patient Be Difficult to Intubate?: The Rational Clinical Examination Systematic Review. JAMA. 2019 Feb 5;321(5):493-503. doi:
10.1001/jama.2018.21413.

39. OTHER PREDICTOR - HEAVEN
Kuzmack E et al. A Novel Difficult-Airway Prediction Tool for Emergency Airway Management: Validation of the HEAVEN Criteria in a
Large Air Medical Cohort. JEM 2018. PMID: 29331494

40. Kuzmack E et al. A Novel Difficult-Airway Prediction Tool for Emergency Airway Management: Validation of the HEAVEN Criteria in a
Large Air Medical Cohort. JEM 2018. PMID: 29331494
OTHER PREDICTOR - HEAVEN

41. Kuzmack E et al. A Novel Difficult-Airway Prediction Tool for Emergency Airway Management: Validation of the HEAVEN Criteria in a
Large Air Medical Cohort. JEM 2018. PMID: 29331494

42. • The existing difficult airway prediction tools are
not practical for emergency intubation and do not
incorporate with physiological data, HEAVEN
criteria more relevant for emergency RSI.
• The HEAVEN criteria may be useful to predict
laryngoscopic view and intubation perfomance
for DL and VL during emergency RSI.