Cardiac arrest is a situation where a person’s heart has stopped pumping blood around the body.
Cardiopulmonary Resuscitation (CPR) is a life-saving technique used to try to restore blood circulation and breathing in a person who is in cardiac arrest.
A critical part of performing CPR is rhythm.
Just as the heart has a regular rhythm while performing normally, usually between 50 and 100 beats every minute, during CPR we must maintain a regular rhythm to maintain blood pressure to keep the blood carrying oxygen to the brain to prevent brain damage.
Brain damage can begin within 2 to 3 minutes of the cardiac arrest due to a lack of oxygen.
Research has shown that a faster rate of between 100 to 120 compressions is needed because every CPR compression can only push about 33% of the blood volume that would be pushed by the heart during a normal heartbeat.
Consistent compressions help to create a pumping action, pushing oxygenated blood to the vital organs which is crucial for survival.
Interruptions to the compressions can cause the blood pressure to drop very quickly resulting in less blood being circulated to the brain and lungs.
Maintaining this rhythm, the rescuer only stops for 2 seconds to deliver 2 rescue breaths after every 30 compressions.
Keeping to this rhythm and allowing the chest to completely recoil between compressions allows the heart to refill with blood which can be circulated by the next compression.
It is important to realise what it is we are trying to achieve by performing CPR on a person in cardiac arrest.
We are not trying to re start the person’s heart.
We are trying to maintain their blood pressure, because their own heart is not able to do that, to keep pushing oxygenated blood to the brain to prevent brain damage so that medical professionals may be able to fix the problem that caused the cardiac arrest.
This is why it must be done with rhythm and consistency, until medical help is available, only pausing to deliver rescue breaths.