Predicting the difficult airway

Difficult to Bag Ventilate

Difficult BVM (MOANS)

• Mask seal
• Obesity
• Aged
• No teeth
• Stiffness (resistance to ventilation)

Difficult to Intubate (LEMON)^

An airway assessment score based on criteria of the LEMON method is able to successfully stratify the risk of intubation difficulty in the emergency department.

LOOK

• Look at the patient externally for characteristics that are known to cause difficult laryngoscopy, intubation or ventilation

• Trauma
• Short neck
• Micrognathia
• Prior surgery
• May also be difficult to bag
  • Body mass index
  • Advanced age
  • Beard
  • No teeth
  • Snoring
  • Dentures

Evaluate 3-3-2-1

• 3 - Ideally the distance between the patient's incisor teeth should be at least 3 finger breadths
• 3 - Distance between the hyoid bone and the chin should be at least 3 finger breadths
• 2 - Distance between the thyroid notch and the floor of the mouth should be at least 2 finger breadths
• 1 - Lower jaw should not sublux more than 1cm

Mallampati

• The patient sits upright, opens mouth and protrudes tongue
• Grades are based on visibility of the uvula, posterior pharynx, hard, and soft palate

Obstruction

• Assess for conditions leading to airway obstruction such as Peritonsillar Abscess (PTA), trauma, or Epiglottitis.

Neck Mobility

• Patient places chin down onto their chest and extend their neck.
• Remove the hard collar and provide manual stabilization in trauma patients.
• Poor neck mobility impacts ability to have airway access alignment.

Mallampati Score

3-3-2 ruleDistance between patient's incisor teeth of 3 finger breadths and distance between the thyroid notch and the floor of the mouth should be at least 2 finger widths

See Also

• Difficult airway algorithm