Top 5 First Aid Tricks Everyone Should Know Part 5: Defibrillation

Scott 8
(Editor’s note: this is a continuation of the “Top 5 First Aid Tricks Everyone Should Know” series written by our resident paramedic/firefighter, Scott. For the other parts of this series: Part 1: Direct Pressure; Part 2: Temperature Control; Part 3: Recovery Position; Part 4: CPR)

AEDFirst Aid Trick #1 Defibrillation.

Unlike the other items on this list, this one requires special equipment. But the fact that cardiac arrest currently rings in as the number 1 cause of “natural” death in the United States and many other countries (more than breast cancer, lung cancer, and HIV/Aids combined); that an estimated 95% percent of cardiac arrest victims die before reaching the hospital or other emergency medical help; and the ease of using an automated external defibrillator (AED)  (not to mention that the price for buying one has dropped drastically in recent years), I couldn’t in good conscience leave it off the list.

Those minutes that it takes for emergency medical aid to arrive can make a huge difference in whether the person survives in cases of cardiac arrest.  How much of a difference? According to the American Red Cross, after a person experiences cardiac arrest, the person’s chance of surviving drops by 7%-10% per minute until treated with defibrillation.

For your reference, in an accredited department in the U.S. (of which most are not because of the expense of getting accredited and maintaining accreditation- for example, only 6 departments in all of Washington State are currently accredited), from the time you hit the last digit on the phone to call emergency aid to the emergency aid starting to drive away from their station, you are looking at about 2-3 minutes. From there, it’s all about drive time to your location.

On average, the accredited standard is a max of 8 minutes for urban, 12 minutes for suburban, and 18 minutes for rural, but to be frank, most departments, particularly when staffed by volunteers, usually won’t hit those numbers and the average will be longer, sometimes much longer.  It’s not difficult to do the math with the Red Cross’ numbers and the average response time numbers to see that having an AED on hand and knowing how to use it drastically ups the odds of you or a loved one surviving a cardiac arrest.

The good news is that the price for buying an AED has dropped dramatically in recent years, such as with this Home Defibrillator, which isn’t that much more than many people spend on a computer, but unlike a computer, could save your life or someone you love. Also, in many places, such as New York State, you can get as much as a $500 tax credit for each Defibrillator unit purchased, which further cuts down on the cost of this life saving device.

But whether you end up getting one for your home or not, many businesses, schools, restaurants, and the like are starting to have these mounted to walls, so even if you don’t have one, it’s good for you to familiarize yourself with the process of using one before the emergency situation presents itself.

Defibrillation is the process of delivering a dose of electrical energy through the heart in the hopes that its normal electrical pathways begin to work normally. This is often depicted on TV and movies, though many times not quite accurately. In the movies, the medical professional places the paddles to the person’s chest and ZAP! They magically come back to life. (After a dramatic number of shocks until “It’s too much, we can’t shock him again! … Come on, live damn you!” *queue dramatic Hollywood pause*)

Once your heart goes into cardiac arrest, the only way to get its electrical system to work properly again is to send a massive (compared to the amount the heart gives itself) amount of electrical energy to stop (yes, stop) all the electrical activity in the heart (known as depolarization). This procedure is so important that creators of the devices have developed the technology to the state that just about anyone can perform it- from a 7 year old in grade school to the doctors in an emergency room.

The heart is a two part pump, one part mechanical and one part electrical. The mechanical function of the heart is governed by the electrical system within the heart. That electrical system, in turn, can be affected by neurotransmitters from the brain (or fancy pacemakers created by the Dr. Frankenstein-like minds of the world). But since we’re talking about shocking someone, we’ll only focus on the electrical system of the heart. Should you want to know how the brain governs it, I direct you to the many medical schools around the country!

When your heart is beating normally, its muscle cells are receiving an electrical shock approximately 60-100 times per minute. When this happens, your heart contracts, forcing blood out to the body. What causes this shock?  Short answer: chemistry. Long answer: The exchange of electrolytes across specialized cells within the heart build up a differing electrical potential on either side of the cell. When this electrical potential reaches a certain amount, it discharges and sends a shock down another unique set of cells within the heart, causing a shock and thus the contraction.

The specific set of cells that regulate the heart rate (in most people) are called the Sinoatrial node or SA node for short. The SA node (pacemaker of the heart) sits in the upper portion of the R atria near the entrance of the superior vena cava. When the SA node sends out and electrical shock, it immediately shocks the atria (the top chambers of the heart). The pulse then gets “held up” in another set of cells called the Atrioventricular node, or AV node for short. The impulse then travels down to the bundle of His (no, not the bundle of hers, sorry ladies ;-)) and then to two pathways called the right and left bundle branches. Then it’s transmitted to the rest of the Ventricles (lower chambers of the heart) through what are called Purkinje fibers. All together this “shock” causes the atria to contract, then the ventricles. The wonder of a pulse!

So what and how do these electrolytes cause this shock? In an attempt not to give a physiology lecture of ungodly length, I will simply say that the main two electrolytes involved are sodium and potassium. Potassium normally sits inside the cell, and sodium outside. Potassium slowly leaks outside of the cell as sodium forces its way in. This creates the differing electrical potential that builds up until the point of discharge because sodium and potassium have different electrical potentials. Other electrolytes also help in creating this differential, and they are calcium and magnesium. For how exactly all these electrolytes cross the cells membrane, I will only say here that it would take way too long to explain in this article; just trust me on this one, they do. All together the harmony created by this yin and yang system of electrical and mechanical systems come together to make that wonderfully thumping thing inside your chest!

So let’s talk about this infamous “shocking” business. When the SA node becomes damaged, or simply isn’t working properly, other parts of the heart start to take over to create the heartbeat. There are millions of foci in the heart that can make this beat happen. The reason why they normally don’t is that the SA node “overrides” them and they accept the impulse from it, instead of trying to create one on their own.

When these foci start to beat on their own, they can create an electrical impulse that simply doesn’t create the mechanical squeeze necessary for blood flow, thus no pulse. When this happens, if you “shock” all of these foci, you get them all to depolarize at the same time. The hope is that the SA node, or some other foci, will take over and create a pulse producing rhythm on its own.

So should there be no electrical impulse at all, like say when someone is “flat-lined”, called asystole, then shocking is pointless, since you would need an electrical impulse to create a beat. So when you see those heroes on the TV and movies shocking someone with a flat-line, if they were actually doctors, be assured that their license to practice medicine would be reviewed after that was discovered. Unless of course, they just say it looked like a fine V-fib! (don’t ask, electrical physiologists go to school for a long time, and about half of you have probably already glazed over from the medical speak at this point.  Don’t think I don’t see you skimming.  Pay attention, you could save someone’s life! ;-))

When someone goes into cardiac arrest, the most common heart rhythm present is known as ventricular fibrillation. This is when all those foci in the bottom of your heart begin to fire off at the same time. The result is a seizure-like reaction that leaves the heart just quivering. No blood is then circulated out of the heart. Because it’s known that this is the most common rhythm, and the only way to fix it is with a shock, the engineers of the world have come up with a way that everyone can deliver this shock when needed. The machine is known as an Automatic External Defibrillator (AED).

An AED can be operated by anyone. There are many different manufacturers of them, and all work similarly. They only allow you to shock someone in ventricular fibrillation. (So no using it on your sleeping friends :(… of course tasers do exist! )

Image-2Once you open the AED, it will tell you a three step process to shock someone, in three different ways. The first is in picture form. It will show you how to turn on the machine. How to place pads (sticky patches that take the place of traditional paddles). It will then show you which button to press to shock the person. The second method is in word form. It will read something like: turn on the machine, place the pads as shown, and press the shock button. Both of those methods are color coded as well. The last form is verbal. Once the machine is turned on, it will begin to tell you to “place pads on patient’s bare chest, plug in pads connecter next to flashing light.” It will continue to tell you this until you do. Once you do, the machine will then tell you not to touch the patient, as it is analyzing the heart rhythm. If the machine sees that the person is in ventricular fibrillation, it will tell you something like “shock advised. Do not touch the patient. Press the flashing light to deliver the shock.” If the shock is not advised, it will tell you that as well. It will then tell you how to perform CPR.

You cannot plug in the pads incorrectly as the manufacturers only allow them to be plugged in one way. The machine will not let you shock someone who doesn’t need it. Several studies have found that when using an AED there is no difference in survival rate after application of shock delivery between lay people as young as 7 years old doing it or doctors.  This isn’t brain surgery.

AEDs have become extremely common place. Many governmental organizations require them to be present in publicly funded buildings, like schools and court houses. Private businesses like casino’s, churches, and large office buildings commonly have them. They can be bought at several national retailers, and doctors often prescribe them to patients at risk of cardiac arrest. (Note: in some places where there isn’t just a straight tax credit to anyone who buys an AED, getting a prescription for one can sometimes at least turn it into a tax deduction.) So next time you are in a public place, look for them. They might just save your life!

Since cardiac arrest is the number one “natural” cause of death in the United states any person in cardiac arrest will require an electrical shock, and because AED technology has progressed to the point of allowing just about anyone to give this shock, defibrillation is #1 on our top 5 first aid tricks everyone should know.

Some people have suggested that CPR be #1 and not #2, since it increases the person’s chance of survival so significantly. I chose defibrillation as #1 because CPR alone will not make their heart start beating again. Defibrillation will. CPR just extends the amount of time a person can be in cardiac arrest and still have this defibrillation work. One study showed that communities with people trained in CPR and AED use had twice as many victims survive a cardiac arrest compared to communities using CPR only. Good quality CPR and rapid defibrillation together will give the person in cardiac arrest the greatest chance of survival. So make sure you know about both!

There you have it! The top 5 first aid tricks everyone should know. With the exception of an AED, you need no special equipment to perform them. They will definitely help save someone’s life. Most people can do them, and knowing them all will help in a very wide range of emergency situations. I encourage everyone to take a first aid and CPR classes if you are interested in knowing more. (There’s even a non-zero chance you might get me as your instructor if you happen to live in the right area… you can marvel at my ability to make the CPR class take far longer than others make it last, owning to my incessant need to teach all my students all the little details of what’s going on in the body and how it all works as I teach.  Come for the CPR instruction, stay for the free medical-school-like detail! You too can roll your eyes at me and frequently glance at your watch as I attempt to cram a seemingly never ending stream of medical knowledge into your head! :-))

Be Sure and Check Out the Other Parts of this series:

*Legal Disclaimer: This article contains general information about medical conditions and treatments. The information is not direct advice for your specific situation, and should not be treated as such, nor should it be viewed as a replacement for proper, professional first aid training. You should never delay seeking medical advice, disregard medical advice, or discontinue medical treatment because of information in this article…. There, I’ve covered myself.  ;-)

[Image via Shutterstock]

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8 Comments »

  1. Larry November 21, 2013 at 1:52 pm - Reply

    I would argue that CPR is more important to know than using an AED.

    - If you know CPR, you start CPR, have someone call 911, and send someone else to get the AED. The AED itself tells you how to use it.

    - If there is no AED you have to start CPR anyway.

    - If you don’t know CPR and there’s no AED, or if you don’t know CPR and the AED says “No shock advised. Continue CPR,” you might just as well start the wake, and, if there’s an AED, hope it can lead you in a chorus of “On Eagles Wings.”

  2. A Disgruntled Brit July 18, 2014 at 8:21 am - Reply

    “That electrical system, in turn, can be affected by neurotransmitters from the brain”

    I was taught that the SAN is completely, 100% independent of the brain and nervous system, as in it generates it’s own pulses regardless of what any neurotransmitters etc are telling it?

    • A Disgruntled Brit July 21, 2014 at 6:11 am - Reply

      Wait, I’ve just thought about it and it makes sense, otherwise how would it know when to speed up the heart etc? Ignore my comment

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