CPR and use of an automated external defibrillator (AED)
This domain examines high-quality adult CPR, safe AED operation and the decisions around when to start, pause and stop resuscitation. Practical marks hinge on compression quality and on verbalising each AED step.
Adult CPR sequence
Place the casualty on a firm, flat surface. Position the heel of your hand on the centre of the chest, lower half of the sternum, and interlock your fingers. Give 30 compressions to 2 rescue breaths: compress 5–6 cm at 100–120 per minute, allow full chest recoil, and keep interruptions under 10 seconds. Each breath lasts about 1 second and should produce a visible chest rise. If you are unwilling or unable to give breaths, perform compression-only CPR. Swap rescuers every 2 minutes to maintain depth.
Using the AED
Turn the device on and follow its voice prompts. Bare and dry the chest; remove patches, jewellery and excess hair, and avoid placing pads over an implanted pacemaker or on wet skin. Place one pad below the right collarbone and the other on the left lower ribs, clear of breast tissue. Ensure nobody touches the casualty during analysis and shock delivery, then resume compressions immediately. For a child, use paediatric pads or the paediatric setting if available; otherwise use adult pads.
When to stop
Stop when emergency services take over, the casualty shows signs of life and begins breathing normally, or you are physically exhausted. If breathing returns, place the casualty in the recovery position and keep monitoring.
Worked example
A 55-year-old collapses and is not breathing normally. You start compressions, a colleague brings the AED and the prompt says “shock advised”. Reasoning: clear everyone, deliver the shock, then immediately resume compressions for 2 minutes before the next analysis - do not wait to check the pulse.
Traps that cost marks
- Shallow compressions, leaning on the chest, or long pauses around AED use.
- Only one shock delivered because the rescuer stops to reassess.
- Defibrillating a wet chest or with someone touching the casualty.