How to perform CPR in an emergency

Cardiopulmonary resuscitation (CPR) is used to treat someone who has stopped breathing, but the method varies depending on the cause. CPR always involves chest compressions, but in some cases mouth-to-mouth resuscitation via "rescue breaths" should also be given. Your first step must be to assess the patient's condition.

• Tap or gently shake the patient. Shout "Can you hear me? Open your eyes. Squeeze my hand." If there's no response, shout for help. Get someone to summon an ambulance and to confirm they have done so. Make sure they tell the ambulance controller that a cardiac arrest is suspected.
• Kneel by the patient and roll them onto their back, pulling from the hip. Tilt the head back, lifting the chin with your fingers to open the airway.
• Put your ear close to their mouth and listen for breathing. If the patient is breathing normally, place them in the recovery position (only if you know how to perform this maneuver) and don't start CPR.
• If the patient isn't breathing normally, or is coughing, breathless or motionless, apply CPR. If drowning or asphyxiation is suspected, alternate 100 chest compressions with two rescue breaths. Otherwise start by applying 600 chest compressions and then alternate as above.

1. Kneeling over the patient place the heel of your hand at the centre of their chest. Cover that hand with the other and lace your fingers, keeping the fingers of the lower hand raised, away from the patient's ribcage.
2. Lean forward with your arms straight till your shoulders are over the chest and press straight down five to  six centimetres (two to 2 1/2 inches). Keep your hands in place but ease the pressure to let the chest rise. Repeat 30 times at a rate of 100 to 120 per minute.
3. If the patient starts breathing normally again, place them in the recovery position. If the patient isn't responsive after six minutes of compressions, continue by alternating two rescue breaths (see below) with 30 compressions until help arrives. If you cannot or do not want to give rescue breaths, give chest compressions on their own.

When giving CPR, carry on until help arrives or the patient regains consciousness or starts breathing again — or until you are too tired to continue. It's also a good idea to print out these directions and keep them in your purse or wallet.

1. Place a hand on the person's forehead and tilt the head back, supporting the chin with your fingers. Pinch their nose to close it, draw a normal breath, seal your lips around the mouth and blow until the chest rises.
2. Watch the chest fall — the complete cycle should take about one second — and repeat once more before resuming chest compressions. If you have enlisted a fellow first-aider, take it in turns; stop pumping the chest while your partner gives rescue breaths, and vice versa.