Airway Assessment – The US Approach

The potential hazards identified on the previous page, and others, have been incorporated into two mnemonics from the American Emergency Airway Management course.

MOANS acts as an aide-memoire for indicators of difficult BVM:

  • M: Mask seal – for example a beard or blood
  • O: Obesity and obstruction
  • A: Age
  • N: No teeth
  • S: Stiff lungs

LEMON highlights patients who may be difficult to intubate:

  • L: Look: a rapid ‘gut-feeling’ assessment
  • E: Evaluate the 3-3-2 rule
  • M: Mallampati score see note below
  • O: Obesity/obstruction (stridor in particular is worrying)
  • N: Neck mobility
3-3-2 rule

A normal patient should be able to accomodate:

3 finger breadths between incisors

3 fingers from the tip of the chin to the neck

2 fingers from the chin/neck junction to the thyroid cartilage.

Image courtesy of LITFL[12]

Note: Mallampati score is assessed, conventionally, by asking a seated patient to open their mouth as far as they can. This can be approximated in the supine patient using a tongue depressor or laryngoscope blade if necessary. If only the base of the uvula, or less, can be visualised, intubation may be more challenging. It is difficult to assess in the immobilised or obtunded patient [8].

Refresh your airway anatomy, watch this video:

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