Basic Life Support consists of the following sequences of actions:

•  Ensure that the casualty, any bystanders, and you are safe.

• Gently shake the casualty's shoulders and ask loudly "Are you alright?"

• Leave him in the position in which you find him provided there is no further danger.
• Try to find out what is wrong with him and get help if needed.
• Reassure him regularly.

• Shout for help (assuming  you are alone).
• Turn the casualty onto his back and open the airway using head tilt and chin lift:

• Look for chest movement.
• Listen at the casualty's mouth for breathing.
• Feel for air on your cheek.

In the first few minutes after a cardiac arrest a casualty may be barely breathing or taking infrequent noisy gasps (agonal breathing). Do not confuse this with normal breathing - treat as not breathing.

Look, listen and feel for 10 seconds to determine if the casualty is breathing normally. If you have any doubt about whether the breathing is normal act as if it is not normal.

• Put him into the recovery position.
• If an ambulance has not been called, call 999 or go for help.
• Check for continued breathing.

• If an ambulance has not been called, call 999 or go for help.
• If you do have the AED and oxygen commence defibrillation.
• If you do not have the AED and oxygen:
• Kneel by the side of the casualty, place the heal of one hand on the casualty's chest between the nipples.
• Place the heel of your other hand on top of the first hand.
• Interlock the fingers of your hands and ensure that pressure is not applied over the casualty's ribs. Do not apply any pressure over the upper abdomen or the bottom end of the bony sternum (breastbone).
• Position yourself vertically above the casualty's chest and, with your arms straight, press down on the sternum 4-5 cm.
• After each compression release all the pressure on the chest without losing contact between your hands and the sternum. Repeat at a rate of about 100 times a minute (a little less than 2 compressions a second).
• Compression and release should take equal amounts of time.

• After 30 compressions open the airway again using head tilt and chin lift
• Pinch the soft part of the casualty's nose closed, using the index finger and thumb of your hand on his forehead.
• Allow his mouth to open but maintain chin lift.
• Take a normal breath and place your lips around his mouth, making sure that you have a good seal.
• Blow steadily into his mouth whilst watching for his chest to rise; take about 1 second for his chest to rise as in normal breathing; this is an effective rescue breath.
• Maintaining head tilt and chin lift, take your mouth way from the casualty and watch for his chest to fall as air comes out.
• Take another normal breath and blow into the casualty's mouth once more to give a total of 2 effective rescue breaths. Then return your hands without delay to the correct position on the sternum and give a further 30 chest compressions.

• Continue with chest compressions and rescue breaths in a ratio of 30:2.
• Stop to recheck the casualty only if he starts breathing normally, otherwise do not interrupt resuscitations

• Check the casualty's mouth and remove any visual obstruction.
• Recheck that there is adequate head tilt and chin lift.
• Do not attempt more than 2 breaths each time before returning to chest compressions.

• If you are not able, or are unwilling, to give rescue breaths, give chest compressions only.
• If chest compressions only are given, these should be continuous at a rate of 100 a minute.
• Stop to recheck the casualty only if he starts breathing normally; otherwise do not interrupt resuscitation.

• Qualified help arrives and takes over,
• the casualty starts breathing normally, or
• you become exhausted.