1. Assessing the Difficult Airway in the ED
University of Utah Affiliated
Emergency Medicine Residency Program
July, 2009
Erik D. Barton, MD, MS, MBA

2. Outline The Failed Airway Defining the Difficult Airway
Difficult Airway prediction tools
Evidence-based experience

3. The “Failed” Airway Multiple Definitions…
Number of failed attempts (e.g., three)
Failure to ventilate with a BVM
Failure to oxygenate
Failure to visualize the larynx

4. The Failed Airway Clinically, 2 types of “failed” airways:
1. Cannot intubate, but can oxygenate
2. Cannot intubate, and cannot oxygenate

5. The Failed Airway Type 1: (Can’t intubate, can oxygenate)
Most common airway problem!
Failure to intubate on 3 attempts by an experienced operator
National Emergency Airway Course
Consider alternative techniques / adjuncts

6. The Failed Airway Type 2: (Can’t intubate, can’t oxygenate)
Oxygen saturation <90% with BVM
Any number of attempts
Surgical airway
Cricothyrotomy
Percutaneous technique

7. Rapid Sequence Intubation
Failed Attempt
Rescue Maneuvers
The first rescue from failed intubation is bagging.
The first rescue from failed bagging is better bagging.
Rescue devices

8. Rapid Sequence Intubation
Failed Attempt
Rescue Maneuvers
Plan in advance
Systematic approach essential
Equipment
Training
…remember “Skydiving!!”

9. The Difficult Airway The DIFFICULT AIRWAY is something you PREDICT…
A FAILED ARWAY is something you EXPERIENCE!!

10. Predictors of Difficult Intubation
The Difficult Airway
Predictors of Difficult Intubation
Rely on luck,….very high stakes
Adopt the Anesthesia checklist?
A simpler, more reliable system is needed.

11. Identification of the Difficult Airway
3 Key Attributes
Difficult Bag/Mask Ventilation
Difficult Intubation
Difficult Cricothyrotomy

14. Difficult Bag/Mask Ventilation
The Difficult Airway
Difficult Bag/Mask Ventilation

17. Difficult Bag/Mask Ventilation
The Difficult Airway
Difficult Bag/Mask Ventilation
Defined as: leak, H2O seal, change operator, sat < 92%, O2>15L, no chest movement
1502 patients, 75 (5%) had difficult BMV
5 attributes by MV analysis: beard, bmi>26kg/m2, snoring, edentulousness, age>55
> 2 attributes = 72% sens, 73% spec
Langeron O, et al: Prediction of Difficult Mask Ventilation. Anesthesiology 2000; 92:

18. Difficult Bag/Mask Ventilation
The Difficult Airway
Difficult Bag/Mask Ventilation
Anesthesiologist’s gestalt 17% sensitive but 96% specific
Only 1/1502 (0.06%) impossible BMV
0.7% impossible intubation, 44% of those had difficult BMV = 0.3% overall
Langeron O, et al: Prediction of Difficult Mask Ventilation. Anesthesiology 2000; 92:

19. Mask seal Obesity Aged (>55) No teeth Stiff lungs
Approach to the
Difficult Airway
Difficult Bag Mask Ventilation
Mask seal
Obesity
Aged (>55)
No teeth
Stiff lungs

20. Difficult Crycothyrotomy
The Difficult Airway
Difficult Crycothyrotomy

23. Difficult Cricothyrotomy
The Difficult Airway
Difficult Cricothyrotomy
little literature guidance
more of a “gestalt”
local neck anatomy probably the only real issue

24. Surgery scar Hematoma Obesity Radiation Tumor Difficult Cricothyrotomy
Approach to the
Difficult Airway
Difficult Cricothyrotomy
Surgery scar
Hematoma
Obesity
Radiation
Tumor

25. The Difficult Airway
Difficult Intubation

27. Predictors of Difficult Intubation
The Difficult Airway
Predictors of Difficult Intubation
Most based on laryngoscope grade
Numerous external attributes implicated
Some systems very complex, some simple
Various definitions of difficult intubation
Mallampati scale widely used, but crude
Difficult to apply complex scales in crisis
Few have been prospectively validated

28. Predictors of Difficult Intubation
The Difficult Airway
Predictors of Difficult Intubation
Dentition
Upper airway attributes
Mouth/oral access
Anatomic abnormalities
Immobilized trauma patient
Facial/neck trauma
Underlying conditions
Short neck
Small occiput
Facial hair
Airway obstruction
Large tongue
High larynx
Small mandible

30. BMV as important as intubation Mouth opening/access
The Difficult Airway
Identification of the Difficult Airway
BMV as important as intubation
Mouth opening/access
Neck extension at AOJ
Neck flexion at CTJ
Mentum-Hyoid-Thyroid distance
Presence/Risk of obstruction

31. The LEMON law Identification of the Difficult Airway
Approach to the
Difficult Airway
Identification of the Difficult Airway
Development of a consistent approach:
The LEMON law
© National Emergency Airway Management Course

32. The LEMON law L ook externally E valuate 3-3-2 M allampati
Approach to the
Difficult Airway
The LEMON law
L ook externally
E valuate 3-3-2
M allampati
O bstruction?
N eck mobility
© National Emergency Airway Management Course

33. L ook externally Identification of the Difficult Airway
Approach to the
Difficult Airway
Identification of the Difficult Airway
L ook externally
Difficult BMV (MOANS)
Difficult Cricothyrotomy (SHORT)
Intubator Gestalt

35. Or some other thyromental distance equivalent
Approach to the
Difficult Airway
Identification of the Difficult Airway
E valuate 3-3-2
Or some other thyromental distance equivalent

37. M allampati Identification of the Difficult Airway Approach to the

38. Mallampati

41. O bstruction? Identification of the Difficult Airway Approach to the

42. N eck mobility Identification of the Difficult Airway Approach to the

44. The LEMON law L ook externally MOANS, SHORT E valuate 3-3-2
Approach to the
Difficult Airway
The LEMON law
L ook externally
MOANS, SHORT
E valuate 3-3-2
M allampati
O bstruction?
N eck mobility
© National Emergency Airway Management Course

45. The Difficult Airway Prediction Tools Do they really work?
850 intubations over 37 months
838 patients underwent RSI
3 failed intubations
452 (53%) could not follow simple commands
370 (44%) were C-spine immobilized
RESULTS = only 32% of ED patients could be assessed by LEMON criteria
Levitan, et al, Ann Emer Med, 2004

46. The Difficult Airway Prediction Tools
Air Medical Prehospital intubations
Swanson & Barton, ACEP, 2004

47. The Difficult Airway Prediction Tools
Air Medical Prehospital intubations
Swanson & Barton, ACEP, 2004

48. The LEMON Score ED study in the UK Prospective, Observational study
June 2002 to September 2003
156 patients undergoing intubation
Compared LEMON scores to Cormack-Lehane visualization grades
Grade 1 view = “easy”
Grade 2, 3, 4 view = “difficult”
Reed, Dunn et al, Emerg Med J, 2005

49. Cormack-Lehane Laryngoscopic Visualization Grades
Grade I
Grade II
Grade III
Grade IV

50. The LEMON Score Reed, Dunn et al, Emerg Med J, 2005

51. The LEMON Score Reed, Dunn et al, Emerg Med J, 2005

52. The LEMON Score Reed, Dunn et al, Emerg Med J, 2005

53. The “LEON” Score Reed, Dunn et al, Emerg Med J, 2005

54. Need a consistent approach Awake techniques by default
The Difficult Airway
Management of the Difficult Airway
Need a consistent approach
Awake techniques by default
Need definition of and preplanned approach to failed airway
No “one trick pony” approach
Alternative devices

55. The Difficult Airway… Alternative devices?
Superglottic: LMA, Combitube, King tube
Fiberoptic devices: flexible, rigid, hand-held
Lighted stylets: Trachlight, Lightwand
Surgical: open, transtracheal

56. Is Nasal Intubation an Option?

57. Putting it all together…
Are there any contraindications for RSI?
Is intubation predicted to be successful?
Is bag-valve-mask predicted to be successful?
Cricothyrotomy difficulties?
Can you consider “awake” laryngoscopy (or nasal)?
Is this a “failed” airway?
What type of failed airway?

58. The Emergency Difficult Airway Algorithm
The Difficult Airway
The Emergency Difficult Airway Algorithm
Emergency airway management is different
Key driver is that patient MUST be intubated NOW
ASA Difficult Airway Algorithm breaks down
Emergency Algorithm addresses necessity
Prediction tools have limitations:
LEMON criteria cannot be universally applied
Consistent use will predict most of the difficult patients

59. The End!
QUESTIONS??