Adult Cardiac Arrest: Step-by-Step CPR and AED Guidance

Adult cardiac arrest is a time-critical emergency, often caused by sudden cardiac arrhythmia, usually linked to underlying heart disease. Immediate action — calling for help, starting CPR, and using an AED — gives the best chance of survival.

Step 1: Ensure the Scene Is Safe

Before approaching the casualty, always ensure the area is safe for you and others. Look for hazards such as:

• Traffic
• Fire
• Electricity
• Broken glass or sharp objects

If it's safe, approach the casualty.

Step 2: Check for Response

Gently shake their shoulders and ask:

“Are you alright?”

If there is no response, shout for help. If someone is nearby, ask them to:

• Call 999 immediately and put the phone on speaker
• Bring an AED if available

If you are alone, call 999 on speakerphone so the emergency operator can guide you through CPR.

Step 3: Check for Normal Breathing

Next, you need to check for normal breathing:

• Open the airway with a head-tilt, chin-lift (place one hand on the forehead and two fingers under the chin, gently tilting the head back)
• Look into the mouth and remove any visible obstruction, but only if it can be easily seen and removed
• Look, listen, and feel for normal breathing for up to 10 seconds

If the casualty is not breathing normally or only gasping, assume cardiac arrest and start CPR immediately.

Step 4: Start CPR Without Delay

Tell the 999 operator that the casualty is not breathing normally. The operator will dispatch an ambulance and guide you through CPR step-by-step.

How to Perform Chest Compressions

• Kneel beside the casualty
• Place the heel of one hand on the centre of the chest, between the nipples
• Place your other hand on top, interlock your fingers, and keep your arms straight
• Press down firmly to a depth of 5–6 cm
• Release fully after each compression, allowing the chest to rise
• Continue compressions at a rate of 100–120 per minute (about two compressions per second)

Tip: You can time compressions to the beat of a familiar song like “Stayin' Alive” or “Baby Shark”, both of which match the right rhythm.

Step 5: Give Rescue Breaths

After 30 compressions, give 2 rescue breaths:

• Re-open the airway with a head-tilt, chin-lift
• Pinch the nose closed and seal your mouth over theirs
• Blow steadily for about one second, watching for the chest to rise
• Allow the chest to fall before giving the second breath

Return immediately to chest compressions. If you are unable or unwilling to give breaths, continue with chest compressions only — these are still highly effective and strongly recommended.

Step 6: Use an AED as Soon as It Arrives

When an AED arrives:

• Switch it on immediately and follow the spoken instructions
• Expose the chest and attach the pads as shown on the diagram:
• One pad just below the right collarbone
• One pad on the left side of the chest, below the armpit
• The AED will analyse the heart rhythm. Ensure no one is touching the casualty during this step.
• If a shock is advised, ensure everyone is clear, say “Stand clear,” and press the shock button.
• Immediately resume CPR after the shock, starting with chest compressions.
• If no shock is advised, continue CPR as before.

Step 7: Continue Until Help Arrives

Continue CPR until:

• The person starts breathing normally or shows signs of life, such as movement, eye opening, or coughing
• Emergency services arrive and take over
• You become physically exhausted

If the Person Starts Breathing Normally

If the person starts breathing normally:

• Stop compressions and place them in the recovery position
• Keep the airway open and the head slightly tilted back
• Monitor their breathing continuously until help arrives

Key Points to Remember

• Call 999 immediately and use speakerphone
• Start CPR if the person is not breathing normally
• Perform 30 compressions to 2 breaths, compressing 5–6 cm at a rate of 100–120 per minute
• Use an AED as soon as possible and follow its voice instructions
• If you cannot give breaths, perform continuous chest compressions until help arrives

Every second counts. Your quick actions can save a life.