The Difficult and Failed Airway
Principles of Rapid Sequence
Intubation
Jason Carter, B.S., L.P.
I. The Difficult Airway
A. Defined
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Difficult to oxygenate and ventilate
Difficult to intubate
Difficult to perform a cricothyroidotomy
B. Predicting the Difficult
Airway
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LEMON law
Look externally
Evaluate the 3-3-2 rule
Mallampati classification
Obstruction ?
Neck Mobility
1. Look externally
• Beard or Moustache
that hinders seal of
BVM
• Abnormal Facial
Shape
• Extreme cachexia
• Endentulous mouth
with sunken cheeks
• Disruption of the
lower face due to
trauma.
• Large central incisors
• High-arching palate
• Receding mandible
• Short bull neck
• Morbid obesity
2. Evaluate the 3-3-2 Rule
• Three finger mouth opening
• Three finger mentum-to-hyoid
• Two finger floor-of-mouth-to-thyroid
cartilage
3. Mallampati classification
• Spaciousness of
mouth
• Done sitting with
head in sniffing
position, mouth wide
open and tongue
sticking out
4. Obstruction
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Foreign object – Magill forceps
Laryngeal tumor
Known or suspected epiglottitis
Known or suspected peritonsillar abscess
Direct airway trauma
Extrinsic airway hematoma with
compression
5. Neck mobility
• Spinal motion restriction automatically
makes the RSI difficult
• Non-trauma patients should be able to
bring their head into the sniffing position
II. Clinical Approach to the
Difficult Airway
• First complication is mechanics
• Worst is esophageal intubation
• Factors in failure vs. success
A. Clinical Techniques
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Re-position the head – non-traumatic
Jaw Lift in trauma patients
Miller blade for epiglottis
BURP technique
Leave inadvertent esophageal tube in place
1 – 1.5 size smaller ETT
III. The Failed Airway
A. Failed airway defined
• failure of single attempt at oral intubation
followed by inability to maintain SpO2 
90% with BVM
• Three failed attempts made by an
experienced airway manager
B. Management of the Failed
Airway
• “Can’t intubate, can
oxygenate” has time
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CombiTube Placement
Digital Intubation
Smaller tube
BURP
• “Can’t intubate, cannot
oxygenate” immediate
response
– Needle or Surgical
Cricothyroidotomy
IV. Conclusion
• General Rule—prepare for the worst and
hope for the best
• Before RSI, determine difficulty of
intubation using LEMON law
• All Spinal Motion Restriction patients are
automatically difficult
• Keep up intubation skills