The “LEMON” mnemonic facilitates airway assessment for predicting difficult intubation.
L: Look externally:
This involves visually inspecting the patient's airway for any signs of difficulty, such as facial trauma, facial trauma, large incisors, beard or mustache, large tongue, or abnormal anatomy
E: Evaluate the 3-3-2 rule:
This rule assesses the patient's mouth opening (3 fingerbreadth), hyoid-mental distance (3 fingerbreadth), and the thyroid-to-hyoid distance (2 fingerbreadth). These measurements can indicate potential difficulties in intubation.
M: Mallampati score:
The Mallampati score evaluates the visibility of the patient's tonsils and uvula. The Modified Mallampati Score:
Class I: Soft palate, uvula, fauces, pillars visible.
Class II: Soft palate, major part of uvula, fauces visible.
Class III: Soft palate, base of uvula visible.
Class IV: Only hard palate visible.
A high Mallampati score (class 3 or 4) is associated with more difficult intubation as well as a higher incidence of sleep apnea.
This assessment looks for any signs of airway obstruction, such as tumors or foreign bodies. Upper airway obstructions usually present with stridor, so listen carefully.
N: Neck mobility:
Neck mobility is evaluated to determine if there are any limitations that could affect intubation.
“LEMON” is a quick and easy mnemonic that can help healthcare professionals identify patients who may have difficult airways, allowing them to plan for alternative approaches to airway management. It has been validated and used in emergency departments and other clinical settings to predict difficult intubation.