What problems can defibrillators fix, and why can’t we use them with all cases? Why is there, apparently, a time limit on their use for a patient?

650 views

What problems can defibrillators fix, and why can’t we use them with all cases? Why is there, apparently, a time limit on their use for a patient?

In: Biology

7 Answers

Anonymous 0 Comments

It can help with cardiac arrest, you can’t use them with all cases as some people have the pace maker. There is a time limit due to the stagnation of blood causing clots which can create another heart attack and or stroke.

Anonymous 0 Comments

Defibrillators do only one thing — jolt the heart muscles. But the muscles need structure, healthy cells and a healthy nervous system to continue functioning.

Think of a defibrillator like the starter motor in a car. The starter uses power from the battery to crank the pistons to get the engine going. Then the starter motor stops adding energy to the system, because the engine is going by itself, burning gasoline.

The starter can’t drive the pistons for very long before it burns out or drains the battery. The starter can’t make pistons fire if the pistons are damaged. The starter can’t run the engine without gasoline providing power. Etc, etc.

Anonymous 0 Comments

The actual electrochemical system of the heart is a little bit beyond eli5, but in short, basically our heart has an electrical system (essentially using charged chemicals in place of electrons moving through metal). That electrical system is how the heart times (“paces”) and transmits (“conducts”) beats. That signal can be generated in a few places called “pacemakers”, and the signal conducts along predefined routes (almost like natural wires) through the atria and the ventricles. This ensures that the heart contracts in the proper sequence and at an appropriate rate.

Now, there are certain very specific instances where the electrical system goes haywire…situations where for whatever reason, the electrochemical transmission system has malfunctioned. If someone gets an electric shock, that’s one example where the heart often was simply jolted out of rhythm, and can be jolted back to a proper rhythm again. Another case is where somebody might have drowned for a short time, and the heart is “stunned” but not dead.

What we see more often clinically are a few things….cases where a person has an abnormally-firing part of the heart, a rogue cell that decides to take over pacemaking, and a defibrillation essentially sends a “hard reset” to the heart, hopefully stimulating a synchronized beat again. Sometimes a person has a pulse and is even awake, but the electrical system has gone haywire (either due to chemical imbalances, long-term damage to the system from high blood pressure and such, much smaller heart attacks that haven’t done too much damage but have messed with the electrical system, etc), and so we do what’s called “cardioversion”, which is like a softer, specifically timed defibrillation. (Extra info: often that involves atrial malfunctions, such as atrial tachycardias and atrial fibrillation, but can occasionally include ventricular malfunctions, specifically ventricular tachycardia with a pulse).

The other time we use it is when people are pulseless, i.e. clinically dead. People often associate that situation with heart attacks, rightly so, but defibrillation is only occasionally useful in those cases. Heart attacks usually involve death of the heart muscle…and even if the electrical system works fine, dead muscle can’t pump. In some cases, there’s enough of viable heart tissue left, but that tissue has been “stunned” due to lack of oxygen, and hopefully a defibrillation, in combination with some CPR, oxygen and medications, can un-stun and resynchronize it. That’s the whole idea. In some cases, this wasn’t due to a heart attack, but perhaps somebody who has lost a lot of blood and got to a trauma center clinically dead, but the heart muscle hadn’t quite died yet, and the blood loss was emergently corrected. (Extra info: Those shockable situations are usually ventricular fibrillation, and occasionally ventricular tachycardia).

Anonymous 0 Comments

The show Chicago Fire seems to portray the defibrillator usage accurately, resetting the heart to a normal rhythm, not bringing someone back from the dead

Anonymous 0 Comments

Your heart muscles are themselves responsible for keeping their rhythm. And they keep in sync by sensing what the rest of the muscle is doing. However there are several conditions that may cause the muscles in the heart to come out of sync with each other. Once you have made sure the underlying cause have been fixed so that the condition does not happen again then you can use a defibrillator to give the heart muscles a jolt so that they all beat at the same time and comes back into rhythm again.

Not all heart problems will cause this condition though. For example if the heart stops there is no muscle contractions to get back in sync. But once you have fixed the cause of the stopped heart it will start up again and may not all start in rhythm so you may need to use a defibrillator then.

And defibrillators do not work unless you have fixed the issue that caused the situation in the first place. It is only used to fix a symptom and not what causes the symptom. So if you have used a defibrillator and the heart muscles is still not in sync then you have not cured the condition and you need to diagnose it and cure it before there is any reason to try the defibrillator again. Sometimes the body is able to cure the issue by its own and sometimes the drugs may take some time to take effect or you may need to give another dose. But it may also be an undiagnosed condition or that there are no cures for the severity the patient have.

Anonymous 0 Comments

The heart is several muscles working together, if they stop working together, no blood gets pumped.
All the muscles doing their own thing randomly and not pumping blood is called fibrillation.

So how do you fix it?

**YOU TURN IT OFF AND ON AGAIN**

The defibrillator is the turning it off part.
It briefly shuts down everything in the heart, by overpowering every other signal.
Then you use stuff like CPR to hopefully turn it on again.
Hopefully rebooting the heart fixes the problem.

But not everything can be solved by a reboot, and often it just stop it from killing the patient then and there, but not fix the underlying problem, such as the thing that’s supposed to coordinating the heart not working.

Do note, if the heart is already stopped, turning it off does absolutely nothing. This is something sooooo many medical dramas get wrong.

As for the time limit, the heart not pumping due to fibrillation means blood isn’t flowing to the brain, so the brain dies. Also the heart it self needs blood too, so that dying as well is really bad.

Anonymous 0 Comments

Defibrillation only fixes ventricular fibrillation or ventricular tachycardia. These are when the heart is beating irrationally and not taking signals from the internal pacing system. Defibrillation causes a burst of electric current that causes the heart cells to pause and allow the pacemaker to take over again.

It does NOT help when the heart has “flatlined” or has stopped beating.