First Aid Primary Assessment: The ABCDE Approach

The ABCDE mnemonic structures the initial assessment of any ill or injured person:

1. A – Airway: Open, clear, patent? (Head tilt-chin lift / jaw thrust).
2. B – Breathing: Rate, depth, symmetry, effort, SpO₂.
3. C – Circulation: Pulse (rate, quality), BP, capillary refill, bleeding control.
4. D – Disability: Neurologic status (AVPU or GCS), pupils, glucose.
5. E – Exposure/Environment: Fully examine (undress), prevent hypothermia.

Key Principles

• Treat life threats as you find them (e.g., control massive bleed before airway if exsanguinating).
• Reassess continuously.
• Call for advanced help early.

ABCDE is universal: EMS, ED, ICU, wilderness, pediatric (with modifications).