Airway Assessment – The US Approach
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 accommodate:
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.
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. [9]
Difficult LMA = RODS [4]
- Restricted mouth opening
- Obstruction
- Distorted airway
- Stiff lungs or c-spine
Difficult surgical airway = SHORT [4]
- Surgery
- Hematoma
- Obesity
- Radiation distortion or other deformity
- Tumor
Refresh your airway anatomy, watch this video.