The facts about cardiac arrest and resuscitation (CPR)

The American Heart Association (AHA) is having its annual Scientific Session and some of the information below is taken from presentations made there.

First, some initial information.

A cardiac arrest is not the same as a heart attack

A cardiac arrest occurs when the heart stops pumping. It may stop pumping effectively because of an arrhythmia or chaotic heart rhythm (like ventricular fibrillation.)

Therefore, in some cardiac arrests, the heart is not at a standstill. But since it isn’t pumping, blood pressure falls to zero and the patient rapidly loses consciousness. Almost always without resuscitation the patient will die. The goal of the resuscitation is to get the heart to beat rhythmically again and raise the blood pressure so that blood can perfuse vital organs like the brain, heart, liver, kidneys and others.

A heart attack occurs when the circulation though one or more coronary arteries is blocked. The part of the heart served by that artery gets starved for oxygen and nutrients and may die. A heart attack may cause a cardiac arrest.

Some basic data on cardiac arrests:

Almost 400,000 cardiac arrests occur in the United States per year.
About 88% of cardiac arrests don’t occur in a hospital, they occur at home. The life you save may be that of a spouse, parent, child, other relative, close friend or neighbor.
Many cardiac arrest victims don’t look ill before the arrest. They may not have any history of heart disease or previous heart attack.
Only 32% of out-of-hospital cardiac arrest victims receive CPR from a bystander. Because of this and other facts, only about 8% of cardiac arrest patients survive when an arrest occurs at home or in public.
Blacks are almost twice as likely to experience cardiac arrests in a public place as whites.
A survey showed that 70% of Americans feel helpless during a public cardiac arrest. The reasons are that those people either don’t know how to do CPR, or don’t do it because there has been a lapse between their training in CPR and when they are called upon to use it.
More men experience cardiac arrests (53%) than women (47%.)
Women tend to have worse outcomes than men when resuscitated.

Early initiation of CPR is important

It follows from some of the above information that if more victims of cardiac arrest received bystander CPR, more might survive. One study looked at how to do just that.

hands-only-cprEmergency Medical Service (EMS) dispatchers were told to get the caller to EMS to start CPR. The dispatchers were given instructions to read to the bystander(s) to walk them through CPR even if they had no previous training. They would read form a script and encourage the bystanders to continue CPR till EMS arrived. Though their instructions were more detailed than this, the AHA recommends the following:

Don’t be afraid; your actions can only help. If you see an unresponsive adult who is not breathing or not breathing normally, call 911 and push hard and fast on the center of the chest.

The data showed that:

More bystanders were willing to attempt CPR
Time from the receipt of the 911 call to the start of CPR decreased
There was an increase in survival from 7.9% to 11.2%

This last data point, that the survival rate increased from 7.9% to 11.2%, might not look like much of an increase. But remember, some of these patients may have been in cardiac arrest for some time before being discovered and there may have been nothing that could have been done to reverse that situation. Or they may have experienced cardiac arrest secondary to another fatal concurrent illness (massive stroke, aneurysm rupture, etc.) that CPR would not cure. And finally, when you do that the math, 7.9% to 11.2% is nearly a 42% increase in survival.

First part of the article

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