1. Jeffrey M. Elder, M.D. Deputy Medical Director
New Orleans EMS Airway Lecture Series: Lecture 1 Predicting the Difficult Airway
RSI Failure Rate 1%
Jeffrey M. Elder, M.D.
Deputy Medical Director

2. When To Intubate? Failure to maintain/protect the airway
Required for successful oxygenation and ventilation
Reflexes avoid aspiration
Clear vocal communication is a good measure for airway protection/patency
Absence of a gag reflex not sensitive or specific as indicator for the need of an airway (swallowing)
Swallowing requires sensing the presence of pooled material and complex muscular actions to swallow
Spontaneous respirations ≠ airway protection

3. When To Intubate? Failure of Ventilation or Oxygenation
Supplemental oxygen not effective: ARDS
Respiratory fatigue/failure: Asthma
Can be reversible: Opioid overdose

4. When To Intubate? Anticipated Clinical Course Examples:
Deterioration of the critically ill
Patient is exposed to a period of increased risk:
Long transport time, air evacuation, etc.
Requires clinical gestalt
Examples:
Head injury/combative
Expanding hematoma
Expanding hematoma of the neck – prevertebral space hematoma may not be visible

5. Approach to Evaluating the Airway
Ask a question: What is your name?
Response can tell you about airway and neurological status
Normal voice, ability to inhale and exhale in a manner required for speech, comprehending the question
Only tells you about 1 moment in time
If unable to phonate properly: perform a detailed assessment of the airway

6. Approach to Evaluating the Airway
Examine Mouth and Oropharynx
Bleeding
Swelling of Mouth or Uvula
Any abnormality that would interfere with the passage of air
Examine Mandible and Central face integrity

7. Approach to Evaluating the Airway
Examine the Anterior Neck, Larynx, and Trachea:
Palpate for subcutaneous air
Tracheal injury, pulmonary injury, esophageal rupture, gas forming infections
Monitor the Respiratory Pattern
Stridor = upper airway obstruction
Subauditory stridor = needs stethoscope to hear

8. Approach to Evaluating the Airway
Observe the chest through several respiratory cycles
Look for symmetrical, concordant chest movement
Paradoxical movement or flail chest
Diaphragmatic breathing – spinal cord injury

9. Approach to Evaluating the Airway
Auscultation of the chest
Assess adequacy of air exchange
Decreased breath sounds in hemothorax, pneumothorax, or other pulmonary process
Monitor pulse oximetry, capnography, and mentation
ABGs rarely helpful in the decision to intubate
Anticipate clinical course!

10. Identification of the Difficult and Failed Airway

11. The Failed Airway
Failure to maintain acceptable oxygen saturation during or after on or more failed laryngoscopic attempts (CICO) or
Three failed attempts at orotracheal intubation by an experienced intubator, even when oxygen saturation can be maintained.
*From Manual of Emergency Airway Management CICO= can’t intubate, can’t oxygenate

12. Clinical presentations of the Failed Airway
There is not sufficient time to evaluate or attempt a series of rescue options, and the airway must be secured immediately because of an inability to maintain O2 sats via BVM. (CICO)
There is time to evaluate and execute various options because the patient is in a “can’t intubate, can oxygenate situation”

13. Four Technical Operations of the Difficult Airway
Difficult Bag Valve Mask Ventilation
MOANS
Difficult Laryngoscopy and Intubation
LEMON
Difficult Extra-Glottic Device
RODS
Difficulty Cricothyrotomy
SHORT

14. Difficult Bag-Mask Ventilation: MOANS
Mask Seal
Obstruction/Obesity
Age >55
No Teeth
Stiff lungs
M: can use KY on beard, but slimy mess
O: resistance (chest wall, abd. Wall) redundant airway tissues
A: loss of muscle and tissue tone
N: face caves in.. Leave dentures or place gauze in cheeks
S: high airway pressures: asthma, copd, pulm dz

15. Difficult Laryngoscopy and Intubation: LEMON
Look Externally
Evaluate 3-3-2
Mallampati Score
Obstruction/Obesity
Neck Mobility

16. Difficult Laryngoscopy and Intubation: LEMON
Look Externally
Gestalt
Gut Feeling
First Impression – “This looks bad!”

17. Difficult Laryngoscopy and Intubation: LEMON
Evaluate Rule:
Relates the mouth opening to size of the mandible to the position of the larynx in terms of likelihood of successful visualization of the glottis by direct laryngoscopy

18. Difficult Laryngoscopy and Intubation: LEMON
Mouth must open adequately to permit visualization past the tongue when both the blade and ET tube are within the oral cavity
The mandible must be sufficient size to allow the tongue to be displaced fully into the submandibular space
The glottis must be located a sufficient distance caudad from the base of the tongue so that a direct line of site can be created to look from mouth to vocal cords as the tongue is displaced inferiorly

19. Difficult Laryngoscopy and Intubation: LEMON
First “3”
Assesses for mouth opening
3 fingers between the upper and lower incisors

20. Difficult Laryngoscopy and Intubation: LEMON
Second “3”
Length of the Mandibular space
Mentum to hyoid

21. Difficult Laryngoscopy and Intubation: LEMON
“2”
Position of the glottis in relation to the base of the tongue
Space from Chin-neck junction (hyoid) to and thyroid notch

22. Difficult Laryngoscopy and Intubation: LEMON
Mallampati
Sitting Up
Head in sniffing position
Open mouth, protrude tongue without phonation
Class I-IV
Class I & II = low intubation failure rate
Class III & IV = intubation failure may be > 10%

23. Difficult Laryngoscopy and Intubation: LEMON

24. Difficult Laryngoscopy and Intubation: LEMON
Obstruction/Obesity
Four Cardinal Signs of Upper Airway Obstruction:
Muffled voice
Difficulty swallowing secretions
Stridor
Sensation of dyspnea
Dyspnea = critical obstruction

25. Difficult Laryngoscopy and Intubation: LEMON
Stridor
Occurs when airway circumference is less than 50% of normal (4.5mm or less)
May quickly lead to total obstruction with administration of opiates or benzos
Loose the stenting of open airways
Prepare for double set up

26. Difficult Laryngoscopy and Intubation: LEMON
Neck Mobility
C spine immobilization may compound the effects of other difficult airway markers
Trauma, RA, Ankylosing Spondylitis
May require video laryngoscopy
Video laryngoscopy – less neck movement

27. Difficult Extraglottic Device: RODS
Restricted Mouth Opening
Obstruction
Disrupted or Distorted Airway
Stiff Lungs or Cervical Spine

28. Difficult Extraglottic Device: RODS
Restricted Mouth Opening
Allowing for oral access to insert device

29. Difficult Extraglottic Device: RODS
Obstruction
Upper airway obstruction at larynx or below
EGD will not bypass this obstruction

30. Difficult Extraglottic Device: RODS
Disrupted or Distorted Airway
Seat/Seal compromised of the device
Flexion deformity of the neck

31. Difficult Extraglottic Device: RODS
Stiff Lungs or Cervical Spine
Increased airway resistance
Severe Asthma
Decreased pulmonary compliance
Pulmonary Edema
Decreased Cervical Movement

32. Difficult Cricothyrotomy: SHORT
Surgery or Disrupted Airway
Hematoma (infection/abscess)
Obesity
Radiation
Tumor
Cric. rate – 0.5% medical; 2.3% in trauma

33. Difficult Cricothyrotomy: SHORT
Surgery or Airway Disruption
Anatomy distortion
Halo Device
Old Tracheotomy, etc

34. Difficult Cricothyrotomy: SHORT
Hematoma
Infection
Trauma or Postop
Not a contraindication

35. Difficult Cricothyrotomy: SHORT
Obesity
Access
Short neck
Large pannus
Subcutaneous Emphysema
Careful palpation to overcome!

36. Difficult Cricothyrotomy: SHORT
Radiation
Distortion of Anatomy
Scar Tissue
Fixed Flexion Deformity of the Spine

37. Difficult Cricothyrotomy: SHORT
Tumor
Extrinsic
Intrinsic
Access and bleeding issues

39. Acknowledgement
Manual of Emergency Airway Management, 3rd Edition. Walls, R. and Murphy, M