The Difficult Airway Flashcards
What will you routinely examine during your airway interview?
Malampati score, thyromental distance, mouth opening, neck flexibility and extension
Predicting difficult airway anagram
O (BMI >26) B (Bearded) E (Elderly) S (Snorers) E (Edentulous)
Mallampati score is based on
how much of the oral anatomy can be visualized (class III or IV can help predict a difficult intubation)
Mallampati score estimates
size of tongue relative to the oral cavity and assesses head and neck mobility
Mouth opening is related to
craniocervical extension
In a Class I Mallampati, you can see
Soft palate
Fauces (arch)
Uvula
tonsillar pillars
In a Class II Mallampati, you can see
soft palate
fauces
uvula
In a Class III Mallampati, you can see
Soft palate
base of uvula
In a Class IV Mallampati, you can see
Hard palate only
Thyromental (TM) distance is an indicator of
mandibular space and can also predict an “anterior airway” (narrow, receded mandibles)
A normal thyromental distance is considered to be
3 finger breadths (>6cm)
Normal value for sternomental distance
~13 cm
Sternomental distance is an indicator of
head and neck mobility (potential single most important factor but rarely studied)
Mouth opening indicates
movement of the temporomandibular joint (TMJ) (some patients will have lock jaw)
Normal mouth opening is considered
3 finger widths
Significantly limited mouth opening is very predictive of
poor VC visualization
What Wilson risk score is considered high risk for difficult intubation
> 8
Parameters involved in Wilson Risk Score
Weight Head/neck movement Jaw movement Receding mandible Prominent incisors
Series of grade views during direct laryngoscopy
Cormack-Lehane
How is the Cormack-Lehane grade determined
by how much of the laryngeal aperture can be visualized
In a Cormack-Lehane grade 1, you can visualize
entire laryngeal aperature
In a Cormack-Lehane grade 2, you can visualize
Only the posterior portion of the glottis is visualized
2A: partial view of vocal cords
2B: only arytenoids/epiglottis visualized
In a Cormack-Lehane grade 3, you can visualize
The epiglottis, but no part of the glottis is visualized
In a Cormack-Lehane grade 4, you can visualize
soft palate visualized only
What grades for Cormack-Lehane predict a difficult intubation
3 and 4
Criteria for difficult intubation
- MP score III or IV
- Cormack-Lehane grade view III or IV
- TMD < 3 finger breadths
- Small mouth opening
- minimal head/neck ROM
Overall incidence of difficult intubation
5.8%
Incidence of difficult intubation for normal patients
6.2% (excluding obstetric and obese)
Incidence of difficult intubation for obstetric patients
3.1%
Incidence of difficult intubation for obese patients
15.8%
Difficult airway is generally defined as
3 or more basic DL attempts from an experienced practitioner
