Start CPR. Kneel by the casualty and put the heel of your hand on the middle of their chest. Correct hand placement for CPR may mean that your hands may touch some of the breast. This is okay.
Put your other hand on top of the first and interlock your fingers. Keep your arms straight and lean over the casualty. Press down hard, to a depth of about 5-6cm before releasing the pressure, allowing the chest to come back up.
Push at a rate of 100 to 120 per minute. Listen to instructions from the ambulance controller, who will tell you what to do and help you to push at the right speed.
Continue to perform CPR until:
emergency help arrives and takes over
the person starts showing signs of life and starts to breathe normally
you are too exhausted to continue. If there is a helper, you can change over every one-to-two minutes, with minimal interruptions to chest compressions
a defibrillator is ready to be used.