Clinical Assessment and Risk Stratification
Look Externally
Any external markers of difficult airway? Examples; Body habitus, beards, midface trauma, jaw malocclusion, short neck, large tongue.
Evaluate 3/3/2
Inter-incisor distance (assess how many fingers can be placed between superior and inferior incisors whenSoft mouth opened wide) should be at least three fingers.
Hyomental distance: At least three fingers from base of mandible (mentum) to hyoid bone
Thyromental distance: At least two fingers from hyoid bone to thyroid notch
Mallampati
Ask patient to open mouth and protrude tongue. Class 1-4 is awarded based on features of airway seen. 1: Complete visualisation of soft palate, fauces, uvula and pillars 2: Soft palate, fauces, portion of uvula, 3: Soft palate, base of uvula, 4: Only hard palate visible. A higher class (3/4) is a possible predictor of a more difficult intubation.
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Obstruction
Conditions which may compromise laryngoscopy and the passage of an ETT e.g. epiglottits, head and neck cancer, ludwigs angina, neck haematoma, airway burn, foreign body.
Neck Mobility
Any restrictions to neck mobility e.g. degenerative/inflammatory spine pathology (OA, rheumatoid, ankylosing spondylitis), trauma (cervical collar/ manual in line stabilisation). Those with limited neck mobility are considered more difficult to intubate.
Emergency intubations are not without risk, not least due to the emergent nature of the procedure itself. A growing body of evidence suggests that the risk accompanying an invasive airway technique may even outweigh its intended benefits of protecting the airway and achieving adequate ventilation. The AIRWAYS-2 and PART studies, both published in the same 2018 issue of the Journal of the American Medical Association (JAMA), concluded that intubation is not superior to placing a supraglottic airway device (SAD) in the out-of-hospital (atraumatic) cardiac arrest setting; and that SAD may be at least as good, if not better than attempts at inserting an ETT.
The 4thNational Audit Project of the Royal College of Anaesthetists and Difficult Airway Society (NAP4) was designed, in part, to look at airway management in ED and highlight any deficiencies that have or could have led to serious harm. Analysis of cases highlighted the following gaps in care:
- Poor or delayed recognition of at-risk or deteriorating patients
- Inadequate preparation
- Insufficiently trained staff
- Inadequate equipment