Evidence‑Based Recommendations for LEMON Airway Assessment

Assessment Components

External facial examination – The American Society of Anesthesiologists recommends that clinicians assess facial features (mouth opening, ability to prognath, head and neck mobility, prominent upper incisors, presence of beard, and the upper‑lip‑bite test) as the “Look externally” element of the LEMON airway assessment. [1][2]
Airway obstruction identification – The American Society of Anesthesiologists advises that any existing airway obstruction or pathology be identified during the “Obstruction” component of LEMON, as these findings may significantly complicate intubation. 1

Consider awake intubation – In patients screened positive for a difficult airway, awake intubation should be contemplated when the patient has difficult ventilation, a high aspiration risk, cannot tolerate apnea, or when emergency invasive rescue is expected to be challenging. (Level of evidence: prospective cohort, 2022) [3][4]
Prepare specialized airway equipment – Immediate availability of specialized airway devices (e.g., video laryngoscopes, supraglottic airways, fiber‑optic scopes) is recommended for patients with a positive LEMON screen. (Level of evidence: expert consensus, 2022) 1
Formulate a backup strategy – A pre‑planned backup plan that includes alternative devices and invasive airway options (e.g., surgical airway) should be established before attempting intubation in a predicted‑difficult airway. (Level of evidence: expert consensus, 2022) [1][2]
Limit intubation attempts and ventilate between attempts – The number of intubation attempts should be minimized, and mask ventilation should be provided between attempts to reduce hypoxia risk. (Level of evidence: prospective cohort, 2022) [3][1]

Maintain access to basic difficult‑airway equipment – Even when the LEMON screen is negative, clinicians should ensure that standard difficult‑airway tools (e.g., bougie, alternative laryngoscope blades) are readily accessible. (Level of evidence: expert consensus, 2022) 1