HOME

Pediatric Anesthesiology
Airway
Pediatric Airway
Congenital Heart Dis
Induction
Quiz

Malig Hyperthermia
Quiz

Preop Preparation
Quiz

Peds Anesth Links
The Difficult Airway - 3
Airway Evaluation

A. History

1. Prior anesthetic experience (Read the old anesthesia records.)
2. Suggestive disorders, signs and symptoms
Hoarseness
Stridor
Rheumatoid arthritis
TMJ disorder
C-spine disease
Oropharyngeal pathology
Stridor
Any mouth, throat, neck or jaw problems?

B. Physical Exam: Predictors of difficult mask ventilation *

  1. Grade 3 (1.4% incidence)
      BMI > 30
      Beard (the only easily-modified risk factor)
      Mallampati class III or IV
      Age > 57 years
      Limited jaw protrusion
      Snoring
  2. Grade 4 (0.16% incidence)
      Snoring
      Thyromental distance < 6 cm
  3. Grade 3 or 4 and difficult intubation (0.37%)
      Limited mandibular protrusion
      Abnormal neck anatomy
      Sleep apnea
      Snoring
      BMI > 30

C. Physical Examiniation:DL difficulty relatively likely: What to look for:

1. Temporomandibular disease
a. Chronic or subacute
i) Arthritis (rheumatoid, psoriatic,
degenerative, ankylosing spondylitis)
ii) Mandibular hypoplasia (small chin)
b. Acute
i) Infection
ii) Trauma
2. Abnormal oropharyngeal anatomy
a. Chronic or subacute
i) Small mouth
ii) Prominent maxillary incisors
iii) Macroglossia
iv) Tumors (especially floor of mouth
or supraglottic)
b. Acute
i) Trauma to tongue (swelling)
ii) Inhalational injury
iii) Ludwigs angina (floor of mouth infection)
iv) Peritonsillar abscess
v) Retropharyngeal abscess
3. Abnormal laryngeal and neck anatomy
a. Chronic or subacute
i) Rheumatoid arthritis
ii)Supraglottic tumors and cysts
b. Acute
i) Epiglottitis
ii) Trauma to neck and larynx
4. Abnormal C-spine anatomy
a. Arthritis (rheumatoid, ankylosing spondylitis,
degenerative)
b. Fracture or subluxation

D. Physical Exam: DL difficulty: How to find it:

1. Focus on the three requirements
for successful DL:
a. Mouth must open (at least a little).
b. Three axes (tracheal, pharyngeal, oral)
must be at least somewhat aligned in
the sniffing (or sniff) position.
c. There must be a place big enough
to put the tongue, and space to see.
2. Mouth opening; TMJ mobility.
(Normal > 4 cm. Enough for blade may be enough
for DL if no other problem.)
3. C-spine mobility; sniffing position:
a. Flexion of neck mainly, then a little:
b. Extension of head (at atlanto-axial joint)
on the flexed neck:
Head Extension
4. Is there a place to put the tongue?
a. View patient's profile
Mandibular hypoplasia?
Protruding incisors?
b. Palpation of neck, mandible, mandibular space
(Mandible < 9 cm suggests difficult DL.)
c. Thyromental distance
(Less than 6 cm suggests difficult DL.)
5. Upright maximal tongue protusion test
(Mallampati classification - see figure below)
Look for soft palate, uvula, tonsillar pillars:
Class I: tonsillar pillars and all of uvula
(only 0.4% were difficult)
Class II: more than base of uvula but not pillars
Class III: only base of uvula
Class IV: no uvula or soft palate
Yes, false positives and negatives do occur.


6. Upper Lip Bite Test
Upper Lip Bite Test
The Upper Lip Bite Test Classes

Laryngoscopic view
Grades I and II Grades III and IV
Mallampati I and II 189 3
Mallampati III and IV 94 14
Upper Lip Bite I and II 251 4
Upper Lip Bite III 32 13


7. Five predictive risk factors:
a. Limited jaw movement (limited opening or protrusion)
b. Poor head and neck movement
c. Receding chin (small mandible)
d. Obesity, BMI > 30


Greg Gordon MD
Updated: