Difficult intubation
A difficult airway describes any situation in which standard airway management-bag‑valve‑mask (BVM) ventilation, laryngoscopy and tracheal intubation, or recognised surgical airway techniques-is anticipated to be, or becomes, difficult or impossible.
In the emergency setting this includes both predicted difficult airways (pre‑procedure recognition) and a failed airway (inability to secure or maintain an oxygenating airway).
The overriding priorities are preservation of oxygenation, avoidance of hypoxic brain injury, and rapid, team‑based escalation through pre‑planned backup strategies.
This section covers recognition and prediction, system and equipment requirements, a practical Plan A→D staged approach, key rescue interventions, causes of post‑intubation hypoxia, and practical pitfalls for exam and clinical practice.
Recognition and prediction of a difficult airway
- Do a focused airway assessment for every patient in whom airway instrumentation is considered (including procedural sedation).
- Use a structured mnemonic such as LEMON and record the predicted difficulty and a Plan A-D on the airway checklist (RCEM PSA).
- No single test is fully reliable-combine findings and assume difficulty when multiple risk factors are present.
- Other predictors include prior difficult intubation, tracheostomy stoma, congenital facial abnormalities, pregnancy (airway oedema), morbid obesity, and acute physiology (hypoxaemia, haemodynamic instability, full stomach).
LEMON (concise)
- Look externally: obesity, short or thick neck, facial/neck trauma, burns, large tongue, small mouth, loose teeth, significant facial hair.