Dear Straight Dope:
Back in the 80s, when I was a teen, both my school and my Boy Scout troop were constantly pushing CPR training in our faces. If everyone in America knew CPR, we were told, life would be transformed for the better. So, 25 years later, has widespread CPR training truly changed life as we know it? (Personally, I've never been called upon to perform CPR in my entire life, thankfully.)
Community CPR training has not by itself transformed life as we know it, but it is part of a suite of advances that have made heart attacks more survivable. Other developments include improved emergency medical services and the greater availability of advanced life support (ALS) gear like defibrillators. And administering CPR can definitely save lives; I know this because I’ve done it. That’s the good news. The bad news is that even with immediate, prompt CPR and ALS, survival rates are worse than you might think.
As an EMT, I performed CPR on three patients; only one survived long enough to be discharged from the hospital. If anything, this success rate was above average. Studies put survival rates for for victims of cardiac arrest who received CPR alone in the range of 5 to 25 percent, depending on circumstances. If that sounds low, consider this: one study found survival rates doubled when a bystander initiated CPR promptly.
The two biggest factors that affect survival are (a) whether the victim’s collapse was actually witnessed by a person trained in CPR and (b) whether the witness was a stranger or not. Factor (a) is pretty simple: if the collapse is witnessed, then the delay in starting CPR is typically minimal and thus damage to the brain from oxygen starvation is reduced. The details concerning factor (b) are perhaps more surprising: bystanders trained in CPR are less likely to initiate CPR if they know the cardiac arrest victim; strangers are 4.6 times more likely to initiate CPR than bystanders known by the victim. Why? Reasons given to researchers for failing to administer CPR mostly boiled down to panic.
So if you’re planning on having a heart attack, I recommend you arrange to have a trained stranger on hand who can start CPR immediately upon your collapse. Most people, of course, don’t get the opportunity for such planning, meaning it’s key that lots and lots of people be trained in CPR. One study calculated for each person actually saved by CPR, 12,306 people have to have received CPR training.
Survival rates are higher in those communities where automated external defibrillators (AEDs) are available in places like airports, community centers, office buildings, and police cars. AEDs can increase survival rates by 22 to 39 percent. That doesn’t mean they’ve made CPR obsolete. Not all heart attacks are due to ventricular fibrillation, the electrical malfunction that defibrillators correct; CPR will keep blood flowing to the brain in these cases and when defibrillators are not available.
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