Was your arrest witnessed?
If there's nobody else around when you have your cardiac arrest - or if there is someone else around and they don't notice that you have died - you have a 3.9% chance of getting out of the hospital with your major brain functions intact. How often does this happen? More than half of all out-of-hospital ("OOH") arrests are unwitnessed.
If a bystander saw you arrest, you have 15.2% chance of survival with brain intact - that's nearly four-times better odds. The moral of this factoid is that you need to always have someone around, and that person needs to know how to tell if you've just arrested. More than one-third of all OOH arrests are witnessed by a bystander.
If a 911 responder got there in time to see you arrest - maybe someone called 911 because you weren't looking all that good a few minutes ago - you have an 18.6% chance of survival with major brain functions intact. A little more than 10% of the time, a 911 responder sees the arrest happen.
Many of you are asking yourselves, "Why is it that my odds of survival only improve by 22% when it's the professionals see the arrest, as opposed to an ordinary bystander?" Good question. Read on.
Who started performing CPR on you?
In one third of the cases a bystander initiated CPR, and in two thirds of the cases a 911 responder initiated CPR. When the 911 responder initiated CPR, 8.7% survived. When the bystander initiated CPR, 11.3% survived - a 41% improvement.
Who first applied the AED or Monitor to your right upper chest and left side chest wall?
An overwhelming 96.3% of the arrest victims had an AED / Monitor applied by the 911 responder, and only 3.7% had one applied by a bystander. When the 911 responder applied the monitor, 9.1% survived. When the bystander applied the AED, 23.5% survived.
Why did so few AEDs get applied by bystanders? First of all, there aren't enough AED's nearby in most locations. Second, fewer than one-third of the bystanders will perform CPR, so why would we think that all bystanders would apply the AED, even if AED's were everywhere?
Why did the bystanders get such better results? An AED promptly applied works far, far better than one applied after the 911 responder gets there.
How representative are these numbers?
Mileage does vary. If you arrest on a farm, your chances of surviving are near zero. If you are in the passenger concourse in the Pheonix, AZ airport your chances of surviving are 75% - an average value for the past ten years. The Phoenix airport gets such good results because there are lots of trained people and AED's nearby, and they practice.
Interestingly enough, the existence of such a wide range of outcome probabilities tells us that most places can do far better than they do.
What does all this mean?
- You do not want to have a cardiac arrest, and you really don't want to have an unwitnessed one.
- If you get immediate, high-quality CPR (chest compressions of two inches or more, 100-120 times a minute with almost no interruptions and with no interruption longer than five seconds) and if you get defibrillated promptly - say, within three minutes of the arrest - you can expect your survival odds to be far, far higher than otherwise.
- Get a personal AED, unless you live alone.