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And now, some Real Life Useful Notes about defibrillators.

If someone near you is unconscious at this moment, call emergency services and let them help you. If your first reaction when faced with a medical emergency is to go to TV Tropes, well, you're probably beyond help.

Common emergency services numbers are:

  • 9-1-1 in North America
  • 1-1-2 in the European Union
  • 9-9-9 in the British Commonwealth and many of its former constituent nations.

Thanks to the Eagleland Osmosis phenomenon, all three of these numbers will redirect you to emergency services almost anywhere around the world. Modern smartphones will often have a separate button to call emergency services, which you can use even without a SIM card. Do this as soon as possible — time is of the essence. You'll find out why later.

In addition, many public places have an Automated External Defibrillator, or AED; if you can see one, run and get it and follow its instructions (or better yet, yell at someone closer to it to bring it over while you call emergency services).

This is a Useful Note. It is designed to help readers understand how things work in real life so that you can compare it to how it works in fiction. It's a way for you to do the research rather than actually apply it to your Real Life. Useful Notes are written by Tropers, not medical professionals, and they carry no guarantee of accuracy (or indeed, usefulness) for your situation. We don't particularly want you ruining someone else's life.


With that out of the way, let's talk about defibrillators in Real Life.

First, it's also helpful to visit the Useful Notes page on CPR, as CPR is a necessary step to save someone's life if you have to use a defibrillator.

When does one use them?

A defibrillator isn't magical, but it is a truly remarkable device, especially modern ones that can act almost like a robotic EMT. But let's get the biggest misconception out of the way first: A defibrillator doesn't restart the heart. It actually stops the heart and allows a rescuer to perform CPR to get it working again.

The reason to do this is that a patient may have a dysfunctional heart rhythm; the heart is technically working, but it's not doing a good enough job pumping blood through the body, and thus the brain and other organs are not receiving enough oxygen. Examples include pulseless tachycardia (the heart is beating too fast and can't pump blood effectively) and fibrillation (irregular beating or quivering without pumping, hence the name "defibrillator").


A quick response time is vital, as even seconds without oxygen can lead to permanent brain damage. Defibrillation has a little longer than that to do its thing; in general, odds of success fall dramatically if defibrillation is not applied within four minutes after the onset of cardiac arrest. For this reason, many public places will have Automated External Defibrillators (or AEDs), which allow a bystander to grab one quickly and get it to the patient.

Defibrillation always goes hand-in-hand with CPR; you need CPR to manually pump blood (and thus oxygen) through the body while the heart isn't pumping blood properly. In fact, if first responders encounter a victim who has been unconscious for a couple of minutes, they will do two minutes of CPR to remove metabolic waste products and bring in fresh oxygen; then they'll start shocking. CPR is immediately applied after every shock to minimize the amount of time the brain spends without oxygen. And even CPR is usually only a temporary measure until doctors can administer drugs to get the heart back to a good rhythm on its own.

Because of all this, you now know not to shock a flatline; after all, if defibrillator can't get the heart going again, what's the point?note  Whether or not a Magical Defibrillator can revive a heartbeat has become a good indicator of which Medical Dramas take their science seriously.

Success rates tend not to be very high, as with CPR, and the odds of successful conversion decrease the more shocks a patient requires. This contrasts with what often happens on TV, where a single shock isn't enough, but the patient revives on the second try.

How do they work?

Magical Defibrillators can work quite differently from their Real Life counterparts.

On TV, you'll often see rescuers dramatically rub the paddles against each other. In real life, this was done because the paddles are covered with conductive gel; rubbing the paddles gently spreads the gel evenly. It's seldom done now, because it can damage the paddles; copious amounts of gel will spread more than enough when you press the paddles against the patient's chest. Most modern defibrillators dispense with paddles entirely and use one-use adhesive pads instead. They don't require the operator to hold the paddles on the patient's chest, and they reduce the risk of accidentally shocking the operator. AEDs in particular use sticky pads; the operator just puts the pads on once, and the machine decides itself when and whether to administer a shock.

On TV, you'll see the rescuer press down hard on the patient's chest, the paddles will give a cool metallic "KACHUNK", and the patient will involuntarily jump several inches off the floor. In real life, there's no need to press down on the patient, no matter how satisfying it may be. Nor will the patient jump; the shock does cause generalized muscle contraction, but the movement is more akin to someone who was startled suddenly.

The pads/paddles aren't placed symmetrically on the chest; rather, one goes on the upper right side of the patient's rib cage, and the other goes on the lower left side. Generally, you will have to remove the patient's clothing as much as necessary to actually contact his or her body with the pads. Rescuers are also advised to remove any jewelry or metal from the patient, including under-wire brassieres. That said, the idea that metal or jewelry can kill a patient if exposed to a defibrillator is kind of a myth; it can cause superficial burns by heating up the metal, but mostly it just reduces the device's effectiveness.

On TV, the defibrillator will recharge with a loud, low, whining noise. This kind of happens in real life, but not the way you'd expect. Modern capacitors charge noiselessly, but medical personnel who used the new equipment expected to hear the whine, and when they didn't, they thought the devices were malfunctioning. Manufacturers have added an audio recording of the whine to let users know it's working.

On TV, the rescuer will dramatically yell "Clear!" before administering a shock. And they do this in real life, too — the instruction is to keep clear of the patient. This ensures that (a) no one gets an accidental electric shock and (b) the machine doesn't accidentally pick up a bystander's working heart rhythm. AEDs will have a pre-recorded "Shock advised — charging — stand clear" warning, but human operators are advised to repeat the warning themselves and physically restrain people from the patient if necessary.

Remember that the job of a defibrillator is to stop a "bad" heart rhythm; that said, they are just as good at stopping a normal one. Not standing clear of the patient is an excellent way to end up with two patients, rather than just one.

After the shock, CPR should continue immediately, both to minimise the amount of time without CPR and to help get the heart back into the correct rhythm. After two minutes of CPR, you check the rhythm and shock again if necessary. It's not uncommon for several shocks to be necessary, but the more shocks needed, the worse the prognosis is.

So what does one do with a flatline, then?

It depends. For the most part, defibrillators are useless where the heart basically isn't beating at all (known as "asystole"). But you can use similar devices to induce "synchronized cardioversion"; the device analyzes the heart rhythm and delivers a countershock at a precise interval. It's not technically defibrillation, it's rarely done outside a hospital, and it can't be done on an automated device. It's for situations where the heart is basically running on idle but not doing anything. Beyond that, you do CPR, apply certain drugs, and possibly try an external pacemaker.

How easy is it to use one?

Surprisingly so; with the advent of AEDs, the medical establishment is effectively trusting laypeople to provide the crucial first few steps of medical care, if only because laypeople may be the only one close enough to the patient to provide it. The AED will include instructions on how to use it, both audio and visual. It will read the patient's heart rhythm, decide whether to administer a shock, give the standard "Clear!" warning, and shock the patient itself. It will also remind you to perform CPR immediately following a shock (which kind of does require someone who knows what he's doing, but if no one can be found, well, a layperson is better than nobody).

In fact, a public-use defibrillator's heart rhythm detector also serves as protection against potentially Deadly Pranks or other misuse; it will not administer a shock unless it detects a heart rhythm that requires a shock. It is possible to beat this system, though, by shaking the defibrillator while it's analyzing, which can fool the software into analyzing artifacts of the movement as a heart rhythm. For this reason, EMS personnel are advised to pull over before analyzing a rhythm in an ambulance. Experienced paramedics on manual defibrillators can usually differentiate this.

Hospital-grade defibrillators are basically expert-only devices, but they're also the closest thing you'll find to a Do-Anything Robot in healthcare. These devices can act as either an automated or manual defibrillator; they also include a synchronized cardioversion system (see the flatline section), a portable ECG monitor, and an external pacemaker. They'll tell you whether the current rhythm is shockable, and even keep track of when you last administered drugs and when to give the next round. Field versions also have built-in blood pressure and pulse oximetry monitoring, and can also read information from invasive monitors, giving real-time data on cardiac output, blood pressure, intracranial pressure, and end tidal CO2. In effect, a hospital-grade defibrillator is an ICU-in-a-box.

Can the character use something other than a machine?

No. TV seems to believe that the defibrillator works on the basis that Lightning Can Do Anything, so if you replicate the lightning (or the assault on the patient's chest), you can replicate a defibrillator. It doesn't work that way.

On TV, you'll occasionally see any electric shock to the patient's chest act as a Magical Defibrillator. If it's through lightning-based powers, you can Hand Wave it as something magical since there's no real-life equivalent to compare it to. But if you're just going to have the patient struck by lightning or hook him up to a wall plug or power line (known in the business as a "suicide cord"), that can also work on TV. In real life, not only would this not work as a defibrillator, but it's also a good way to cause the conditions that would require a defibrillator to get rid of. The electric shock of a defibrillator is specific, timed, targeted, and measured; a wall outlet's only concern is powering the TV you're using to watch your shows.

Similarly, on TV any harsh contact to the chest might work as a defibrillator; this idea suggests that it's not the electricity so much as the physical contact that's doing the work. As such, you may see TV characters randomly and indiscriminately whack the patient on the chest to get their heart going again. It is kind of related to the "precordial thump", a last-ditch CPR effort which is precisely aimed and timed (so not indiscriminate), and which is basically not used medically anymore.


The defibrillator actually predates CPR; CPR was invented in 1957, but defibrillation was first tested in 1899 and first used on humans in 1947. That said, defibrillators wouldn't become field medicine until the 1960s, when the move from AC to DC defibrillation made portable units possible. More effective biphasic defibrillators were invented in the 1980s.

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