by Kaitlyn Edwards

Created on: September 16, 2010   Last Updated: November 30, 2011

Cardiopulmonary resuscitation (CPR) is a combination of breaths and chest compressions (at a ratio of 30 compressions to 2 breaths) to mimic the natural action of the heart and to pump blood around the body, transporting oxygen from the lungs around the body, and carbon dioxide back to the lung. It is important that this is preformed adequately in order that the organs, particularly the brain, are adequately perfused and as such, have a good supply of oxygen in order to reduce the risk of long term damage. It is used in two situations.

After completing the primary survey, CPR may be commenced after checking for breathing. If breathing is absent, or the person has agonal breathing (occasional, infrequent and abnormal gasps), CPR should be commenced (after summoning professional help). The current guidelines do not advocate checking for circulations, as was the previous guideline. This is because, unless people are used to doing this regularly, it is unreliable. People often thought they felt a pulse or used their thumb and felt their own pulse whilst checking. It is also currently accepted that if a person is in respiratory arrest, they are highly likely to go in to cardiac arrest. Current thinking suggests that less damage will be done by performing compressions on a person whose heart may still be beating, than allowing people to check for circulation and incorrectly believing there is a circulation.

CPR, performed correctly and effectively, in essential to maximize a person's chance of survival following a respiratory or cardiac arrest.

The second situation in which CPR should be used is less obvious. When  a person is choking, if they lose consciousness, CPR is used in hope that either the breaths will force the blockage further down, in which case it would block one of the bronchi, and allow the other lung to clear. Or, that the compressions, which work a lot like chest thrusts which are used on children, babies and pregnant women, will force the blockage up and out. Whilst this is perhaps not as effective as backslaps and abdominal thrusts, a person who is choking who then loses consciousness is likely to have done so due to hypoxia (lack of oxygen), so it is important that the casualty is oxygenated. Also, hypoxia is one of the reversible causes of cardiac arrest, so by preforming CPR, it is a way of reducing the risk of cardiac arrest. It would also be very difficult to roll an unconscious casualty and perform back slaps simultaneously.

In conclusion, CPR should be performed when a person is not breathing adequately, regardless of whether or not they have circulation, and when a choking casualty loses consciousness. In both these situations, professional help should be summoned.

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