The LEMON law was developed by the National Airway Management course for identification of the difficult airway.
LEMON is a mnemonic for
L: look external
E: evaluate by the 3-3-2 rule (distance between incisors, hyoid-mental distance, thyroid to floor of mouth distance)
M: Mallampati score
O: obstruction to the airway
N: neck mobility
Features to look for externally (original score looked for 7 items):
(1) facial trauma
(2) size of incisors
(3) beard or moustache
(4) size of tongue
|
Parameter |
Finding |
Points |
|
facial trauma |
absent |
0 |
|
|
present |
1 |
|
size of incisors |
not large |
0 |
|
|
large |
2 |
|
beard or moustache |
absent |
0 |
|
|
present |
1 |
|
size of tongue |
small or moderate |
0 |
|
|
large |
1 |
|
distance between incisors with mouth wide open |
3 or more finger breadths |
0 |
|
|
0 to 2 finger breadths |
1 |
|
hyoid-mental distance |
3 or more finger breadths |
0 |
|
|
0 to 2 finger breadths |
1 |
|
thyroid to floor of mouth (thyroid to hyoid distance) |
2 or more finger breadths |
0 |
|
|
1 |
|
|
Mallampati score |
Class I, II or III |
0 |
|
|
Class IV |
1 |
|
obstruction to airway |
absent |
0 |
|
|
present |
1 |
|
neck mobility |
absent (limited) |
1 |
|
|
present |
0 |
total score =
= SUM(points for all 10 items)
Interpretation:
• minimum score: 0
• maximum score: 10
• A higher score was associated with a difficult airway but intubation difficulty could occur even with a low score.
• The Mallampati score was not felt to be useful for intubations in the Emergency Department.
• The items most useful for intubation in the Emergency Department were large incisors, a reduced inter-incisor distance and reduced distance from the thyroid gland to the floor of the mouth.
Specialty: Anesthesiology, Surgery, general, Pulmonology, Cardiology, Emergency Medicine, Otolaryngology
