Inside a Zoll defibrillator - with SCARY capacitor

[@nixxonnor]

The first voice message when the batteries were inserted was "Are the batteries new, press the button" After power on: "Electrodes, adult. Unit OK", "No shocks given", "Stay calm", "Examine reaction", "Call for help" x 3 Then "Open airways", "Examine breathing", "Fasten electrodes to the patient's bare chest",

[@jwalster9412]

Interesting.

[@aaronbrandenburg2441]

Even though my only language is English I thought that it might be saying something on this lines and does make sense now that you have effectively translated it and I'm sure everybody would agree that it was nice of you to do this for the rest of us non Norwegian speaking folk thanks

[@davidmurn772]

I'm a big fan of the Zoll unit's as we use them at work. The Australian units (from start to finish) say: Adult pads. Unit OK. Stay Calm. Check Responsiveness. Call for help. Attach defib pads to patients bare chest. Don't touch patient, analyzing. Shock Advised. Don't touch patient, press flashing shock button. Shock delivered. Continue CPR.

[@UpLateGeek]

Or in Clive's case, "Fasten electrodes to the patient's _bear_ chest" 😄

[@Murgoh]

I don't speak Norwegian but I do speak Swedish and obviously English (I'm from Finland) and I was able to easily understand the text instructions though the speech was less clear to me. There's a (literally) funny difference though, in Norwegian "rolig" means calm, in Swedish it means fun or amusing.

[@19CW86]

Used same AED in real scene. Older gentleman fell on the floor at mall, and I saw that. My friend was with me and we realized that the man was not breathing and he was lifeless. My friend started cpr and I called help and ran to get AED. I also told the security where is the patient and he waited the ambulance outside. We pushed the shock button 4 times during cpr and before ambulance came, after 4th time man woke up. Paramedics connected aed to laptop to get information how many joules it had used. Never forget how thankfull the man was. He was 76 years old

[@nequastar1826]

good on you man, respect

[@cicianamumu]

I just want you to know how lucky you were that the man actually woke up after using the AED on him. This does not happen often! Great job!

[@gloomyblackfur399]

From a Zoll manual, "Use of Panasonic, Rayovac, or Varta batteries may result in significantly longer defibrillator charging times than those required during emergency situations." Hopefully they learned about Panasonic's crappy batteries through testing and not real-world experience.

[@noggin73]

Varta don't have a great track record! The destroyer of old motherboards.

[@RT-qd8yl]

I'll always stand my my "Poweer" batteries. Yes, two Es. With a picture of a tiger on it. 😎

[@phils4634]

Yet, Panasonic Eneloops are generally regarded as the very best rechargeables.

[@littlegrabbiZZ9PZA]

That, and this is a medical device, so in most jurisdictions the manufacturer has to give you a list of "approved" power sources the device was tested with. The list *can* have only one entry, but to avoid supply chain problems it's usually 3-5. Using the device with unapproved batteries voids the certification, and dumps a lot of liability for any problems on the user and/or the person who put the "wrong" batteries in.

[@jada1173]

​@@RT-qd8yl yellow/gold batteries with black tiger? Hellesens or something? Back in the 80's 😄

[@nicolek4076]

My father was recovering in hospital from an myocardial infarction, when I went to visit him. He had recently retired from an academic post in a medical electronics research centre at Imperial College. I found him holding an impromptu seminar round his bed with a group of medical students about the way that defibrillators work.

[@johnopalko5223]

I like your dad.

[@spvillano]

Can't blame him at all. The A&P, as well as the biochemistry involved in normal cardiac function and defibrillation/cardioversion is fascinating and I've actually given similar lectures to medics in the Army.

[@chrisbullock613]

What a great guy 😀

[@nicolajaynehodson9223]

kudos to your Dad ... I love meeting people like him and gettign gems of information from them

[@ellenorbjornsdottir1166]

@@esecallumyou know that whole memeplex is an op, right? you know the virus is doing everything your influencers told you the shot would, right? N95 with everything you do, everywhere you go, with everyone you know, and every plant you grow, and HEPA or MERV13 at home. thank me later

[@WizardTim]

You can trick the AED into delivering a shock quite easily, connect a 50 ohm resistor to the paddles output, this will make it think it's connected to a person, it will give the 'no shock advised' prompt if you just do that, but you can then connect across the 50 ohm resistor a signal generator outputting a ~2 Hz sine wave which is close enough to VFIB (aim for ~1 mV across the resistor), you'll then get the 'shocked advised' prompt when it analyses and it will charge up the capacitor and arm the shock button, you can then disconnect the signal generator (otherwise you will blow it up, adding some series protection resistors to the signal generator is advisable and helps get the 1 mV right) and press the shock button and enjoy the resistor being vaporized in a couple milliseconds. Here's a video of me blowing up a resistor and a capacitor with an old LIFEPAK 12 defibrillator. kzbin.info/www/bejne/jWXMl6GCmKZ8eq8 I vote for a return of your roulette resistor wheel, which 50 ohm resistor(s) will explode? Place your bets now! Also to add to your mention at the end, I want to also mention as strange as it sounds AEDs work exactly the same on women, but women statistically are significantly less likely to survive out of hospital cardiac arrest even when an AED is present. Many people aren't sure if they will work correctly (eg. the male only pictograms) or are afraid of legal consequences, so unfortunately some people die next to an AED that isn't used. Furthermore in the event you're the Good Samaritan for a stranger in cardiac arrest, you get to be the main character, none of this "okay I'll wait here for you to call your manager to ask if I can borrow your AED", you just take the thing, Good Samaritan and necessity laws generally extend to allowing you to even break and enter to retrieve an AED without any liability.

[@theussmirage]

The defibrillator analyzers we use to test these things work in a very similar manner, except with a cardiac waveform generator. It won't fire with a normal rhythm, but you can set it to several types of arrhythmia and the AED will react accordingly. It even times the delay between the waveform and the output from the defibrillator, which typically is a few milliseconds. Someone needs to send Clive a full/manual defibrillator to tear down, there's so much more the bigger defibrillators can do

[@alexanderkupke920]

Having just received a fresh up of my first aid training, including a demonstration with an AED trainer device (it simulates different situations, but does not actually give a shock and is used with a training dummy) I have to add something very important. The training part actually only was showing what the device looks like and what the instructions look and sound like. The pictures and speech instructions are so easy, everyone can use them in an emergency. And the software of those is safe on a human. The only thing you can do wrong with those in a medical emergency, where you have symptomes of a herat attack or just in general an unconscious person, is to not use them.

[@martinbalmforth2665]

My dad owes his life to a defibrilator. He was in vf after getting covid. . Local plod used it on him to get his heart to behave. In my eyes, that is the best invention ever

[@tdurmon]

I was a paramedic and worked in EMS many years ago. AEDs are amazing devices! I was trained on the use of an AED as a first responder and EMT, prior to becoming a paramedic and using the type of defibrillator you see on TV and in hospitals. We’d ordinarily start out at 120 joules, increasing to 200, then 300 joules, if necessary. (I believe that’s accurate…it’s been a long time) While there often is a bit of muscular reaction to the shocks, it’s nothing like you see on TV. No one is bouncing off the table! But I can tell you that defibrillators DO save lives!

[@MyFriendlyPup]

Clot jab has made defibulators as common as pay phones

[@rdizzy1]

@@MyFriendlyPup Almost no one would be using a defib on someone with myocarditis. Most cases are mild, and there were 1.5 million cases in 2013, almost a decade prior to the covid vaccine.

[@PetraKann]

Has there been an increase in heart attacks since 2021?

[@12345.......]

Thank you for saving lives. That's a rough job

[@12345.......]

​@@PetraKannstop, antivax nutter

[@G7OEA]

I used to provide it support for zoll in the Uk and have had long conversions with their service techs. I am also a cpr trainer and former ambulance tech. The AED plus was a bi-phasic. Meaning it fired the shock back and forth across the heart. The AED measures the impedance of the body and calculates the energy required in joules. Usually 360 joules. The model you have is a semi-autmatic meaning. You have to press the shock button. If you don't press the shock button within a time, limit the AED will discharge the capacitor into an internal sane load. The AED does a self test once a day. During the test tests the pads and if there are any faults, the green tick goes out and and the red cross comes on. The sensor is an accelerometer. It measures depth and rhythm. The data port is used to download the data, and it shows the heart rhythm and also the compressions measured by the pads.

[@FeatherdevNet]

That data port also gives information like the serial numbers, version numbers of the software/firmware running on it. The set voltages for the different countries and other configuration settings.

[@MultiVogon]

There you are, you've confirmed what I thought about the sensor detecting movement so it can calculate the depth/speed of CPR, and thus know if it is potentially effective or not. I like that design - the ones I have trained on just have the two pads & cpr is done direct to the chest - I prefer this design for sure!

[@MrDuncl]

Thanks for the detailed description. I was thinking modern AEDs do more than just discharge the capacitor in one go. I guess that is why so many thyristors are needed.

[@mdpaver1]

One of these just saved my 2 year old’s life. Will forever be grateful to the scientific and engineering community. The recovered data with integral to the decision to give her an ICD.

[@Embeddedtronics]

My mom was saved by a device like this twice. She wore a Zoll Lifevest before they were able to her pacemaker installed. Amazing device!

[@RyTrapp0]

Huh, didn't know that wearable defibs were a thing, interesting

[@JamesTK]

I know someone who was saved by an AED too, they're awesome. They ended up getting a ICD (basically defib implant) due to a congenital heart defect. They've received some boots from the implant since, said it hurts like hell, but glad to have it to keep them alive.

[@mumbaiverve2307]

Aren't defibrills and pacemakers 2 different things ?

[@JamesTK]

@@mumbaiverve2307yeah, but both deal with the heart in different ways

[@psirvent8]

@@RyTrapp0 Implantable defibs are a thing, and not to be confused with pacemakers.

[@John_Ridley]

I was responsible for maintaining a Philips AED about 10 years ago. When the battery aged out I cracked it open. It was just ten A123 cells inside, the difference is that it had a sealed plastic case around it and cost $150.

[@MetalheadAndNerd]

The case was probably hand-made by Dutch virgins, as Dave Jones would assume.

[@theussmirage]

The newer Zoll AEDs my hospital uses also happen to be powered by 123 cells, except they've innovated by adding a battery door 😅

[@BobBasshead]

Anything medical related costs 10X above normal cost.

[@ScaniaMF]

Same for Schiller Fred easy-Batterys. Inside the blue battery-box are simple A123 cells

[@android584]

That happens when the government decides to give the medical industry a taxpayer funded gravy train.

[@brownthunder3944]

As a medical engineer, i love this. We dont often get to take defibs apart to this level so this is seriously awesome

[@spvillano]

And the fine fun I could have repurposing the HV charging and capacitor... No, I must use my powers for good... ;) Such as a linear induction motor driver to launch a drone - which would be entertaining when the wings come off... :P

[@theussmirage]

Fellow biomedical engineer here, at my hospital we have service contracts on all our AEDs so the guys at Zoll get to have all the fun. The anesthesia machines I specialize in certainly make up for it 😂

[@keleighshepherd345]

Radiotherapy linear accelerator engineer here, I've always wanted to take one apart to see how it ticks! We have one outside the machine room whenever we're servicing the high voltage areas of the linac because 150kV tends to have a somewhat negative effect on the body 😅

[@weeardguy]

@@keleighshepherd345 The closest I got to a LINAC was during a job interview I once had. One of the engineers took me into the machine-room and showed me the many different assemblies. The sticker on the metal cover on the HV power supply did not beat around the bush: 'Voltages inside this unit can and WILL KILL YOU! LETHAL CURRENTS AND VOLTAGES RESIDE EVEN AFTER DISCONNECTION FROM MAINS POWER! DISCHARGE UNIT BEFORE OPENING! NEVER WORK ALONE!' The guy who showed me around very casually slapped his hand on the metal cover of the HV supply like 'And our trusty HV supply...' I really did take a step back ;) . And when he said I could reach in more to see the filament of the wave-guide glowing (so tiny for such a huge machine!), he was being funny again: 'So... uhm, just to tell you, you can see the filament and from the manual they say that you can actually touch the glass wave-guide... but from our experience it holds quite a static charge... so just don't touch it... haha'

[@spvillano]

@@theussmirage well, with flammable anesthetics, things could get quite, ahem, entertaining... ;)

[@Graham_Shaw]

The best bit about this video for me is Clive being so excited about a high quality product that really can save lives. A truley quality, innovative design, that's serviceable, and uses non-bespoke cell packs to power it. Cheers for the tear down BC!!

[@Gassit]

Louis Rossmann would approve.

[@restorer19]

I mentioned it in a livestream a few days after it happened, but I got one of the (I presume) less energetic defibrillations/zaps in an ambulance back in September. Thankfully it was to reset an SVT (supraventricular tachycardia, i.e. "above" the ventricles, so not one of the super life-threatening arrythmias, but still dangerous if there are complications or comorbidities) - my heart's atria (the upper section of muscle) was beating at around 230 BPM, and the ventricles beating at maybe half that, resulting in barely-effective circulation. That kind of arrythmia usually happens because of some physical or physiological issue that causes the heart's main pacemaker to stop temporarily, and if it resets itself at the wrong time (or so I understand), or if there are anatomical abnormalities, or electrolyte issues, it can set up a mostly self-sustaining electrical loop going around and around the heart conduction paths. At best, it's extremely uncomfortable. At worst, it can cauce insufficient blood flow to the heart and various organs and, if it lasts long enough, damage. I was dealing with severe lung and other circulation issues at the time, so after about a dozen attempts without being able to get an IV because of very low blood pressure, they asked if I wanted to try a shock instead. "Yes, PLEASE!" It was like having a firework go off in front of me at the exact same instant I got tackled from behind by a large person. My heart rate immediately halved, blood pressure went back up to normal(ish), and I felt better in seconds.

[@Haaraff]

The grey plastic pad in the middle indeed monitors rhythm and depth of chest compressions. The unit will give feedback accordingly such as "Herzdruckmassage gut" (I only know these units with German lines, meaning "compressions good") or "Fester drücken" ("press harder") and even give you a rhythm like a metronome.

[@MattyEngland]

Resuscitation to music, I like it

[@themanhimself3]

@@MattyEngland Coming back from death with a party.

[@ianstewart7605]

@@MattyEngland "Stayin alive, stayin alive!"

[@wrecksandtech]

@@MattyEnglandit was a graveyard smash

[@BPantherPink]

​@@ianstewart7605 Yes...that's the beat to follow for a hundred compressions per minute rate !!

[@chadhelmer3835]

The tempo of the song "Stayin Alive" is the ideal tempo for performing CPR. Zoll (at least at one plant in the US) will play a clip of the song over the PA system whenever one of their products saves a life.

[@gutschke]

I was always told to sing "another one bites the dust". Apparently, that song works quite well to keep the correct beat -- and while morbid, it's very memorable.

[@DonaldZiems]

​@@gutschkeboth have the same tempo: 120bpm

[@smj____]

How does the plant know zoll has saved a life? It doesn’t report back and just because you get the heart going again the patient may die…?

[@chadhelmer3835]

This is done when the event is reported to Zoll, so certainly this doesn't include every single event. ​@@smj____

[@zolar7a]

During lifeguard training we had a dummy unit that was just a speech module and a push button. The idea was to be able to drill the steps so we wouldn't be hesitating during an actual emergency. The real units are designed to be thrown around by someone in a panic, set up on a wet pool deck and applied to a soaking wet body all without electrocuting the rescuers.

[@RT-qd8yl]

22:08 I was taught in fire training that accurate and proper CPR *will* result in fractured ribs in the majority of patients. In especially weak or elderly patients it can even result in major, potentially life threatening trauma. That's one reason why any time CPR is given or even attempted, prompt medical care is needed even if the patient regains consciousness or feels fine afterward.

[@ragetist]

Oh lawd it must feel horrible crunching an elder like a bag of Lays while trying to remind yourself that you're doing the right thing.

[@RT-qd8yl]

@@ragetist It's definitely a weird feeling

[@feanenatreides]

So true. I've worked in nursing homes and when writing up DNR orders with families of very far gone residents it was sometimes hard not to say that breaking the ribs an 85 year old with advanced dementia to maybe keep them alive for a tiny bit longer isn't necessarily the kindest thing. But that part of the conversation was beyond the scope of my duties.

[@Blazer02LS]

Not fun. Worse is doing CPR on a baby. @@ragetist

[@spvillano]

@@ragetist it was, as I fractured my wife's ribs performing CPR, did so on healthy soldiers previously. With my wife, that was two weeks of nightmares reliving the ineffective CPR - she was down too long and was septic as well.

[@tronjet66]

I briefly worked in a hospital. We would routinely test AEDs and defibrillators with a device called a patient simulator, does what it says on the tin. It was really fun to fire the defibrillators off ETA: it does fire the full charge though the patient simulator, it can't tell the difference between the patient simulator and a patient. Ultimately we always want to fully run up the unit, if we didn't we might find out that things aren't working properly at the worst possible time

[@nicolajaynehodson9223]

yep, patient simulators and live defibs are used in health profesional / Ambulance staff training settings as well

[@JamesTK]

@@nicolajaynehodson9223 wouldn't want to be touching the simulator then, in case you get an indirect boot?

[@nicolajaynehodson9223]

@JamesTK basically although you shouldn't get a boot of the simulator as the pad cable plugs into the simulator along with the ecg leads. You then use training pads on the chest of Annie/ rescue mannequin

[@iandennis7836]

Those were the days......😂

[@dean5263]

Thanks to whoever sent this to you. Dad was a linesman and I worked in a repair shop where I was exposed to the tube driven high voltages. Fun times.

[@Totalinternalreflection]

Do not explode, babies. Duly noted. I imagine that would make for quite stubborn stains. Seriously though people, familierize yourself with where these things are in your local area, they can be found in many locations on buildings, in supermarkets etc, but it's worth knowing exactly where should you be in a position to need one fast, you could save someone's life. They are designed to be easily used by anyone with no prior experience. Very easy to follow instructions and the computer does everything except sticking the pads on, it then tells you what to do and not do as needed.

[@nhcs2k]

I think I laughed a bit to hard about the "maybe exploding baby". But this makes my day. 😂

[@janosnagyj.9540]

Let's just not forget how he continued on, saying ..."and 💩in the pants" 🤣😅

[@RT-qd8yl]

Ballistic dummy labs needs to whip something up... For science.

[@ucitymetalhead]

I thought when he said that about pooping "more than usual?"

[@spvillano]

We did have one of the old model defibrillators, all manual mode stuff, monophasic shocks, etc. Granted, this was decades ago as well... One day, things were quite dull, everyone was caught up with work, no patients in the TMC (troop medical clinic) and we had a new medic fresh out of Fort Sam Houston (military medical school). We convinced the kid that you could cook a hot dog at 120 joules... Our PA "owned" the clinic and was walking past when the discharge occurred and hotdog festooned all close by, as well as shot to the ceiling, walls, etc. "I don't care, as long as you clean that stuff up now". Those old Vietnam vets were a bit hard to rattle. Impressive, they can make planets now!

[@e4tshtanddie]

I don’t usually burst out laughing at his videos but the comedic delivery was spot on.

[@1o1s1s1i1e]

I started training as a lineman in 1977 and CPR was was given every year. There was a total of seven weeks of school over seven years before becoming a journeyman, it was part classroom and actual work in the training yard. Pole top rescue was done with 150 pound dummy, no not me the other dummy, and we had to clear the dummy from contact, give him three breaths, get a hand line around under his armpits and pull enough tension on the line to lift him before cutting his belt, then lower him to the ground and once back on the ground start CPR. Back then you hit the sternum once to try and get the heart back in rhythm then start CPR, but they quit that after a few years. Very nice device! Not sure if the crews in our area carry a device like that Clive, but if I see any in my travels I will ask.

[@braixeninfection6312]

Ah yes the good old pericardial thump. Aka punching them lol

[@hedgeearthridge6807]

A few months ago at work someone fell out in the cafeteria, and thankfully some HR staff who were CPR trained grabbed the AED and went to work on him. And he lived! He has to take about 4 months to recover as the heart attack took a heavy toll on him, but he's going to be ok. And aptly we bought a lot more AEDs and stationed them across the factory.

[@David_Hogue]

I used a training version in my most recent first aid class. I recommend taking a class.

[@digi-tal]

22:11 When I did First Aid training we got told if you’re not breaking ribs you’re not doing it hard enough!

[@MrDuncl]

We were told "Don't worry about breaking ribs. The patient can recover from that."

[@michaelcherry8952]

So a defibrillator literally turns your heart off and back on again (well, it turns your heart off and hopefully the heart restarts on its own). Seems like power cycling works with practically everything! I have to say, this is the first time I've seen a deep dive into one of these units and it seems to be really well designed. The audio/visual prompts are a great idea because even with training, it's very possible to panic a bit and forget the sequence. The fact that it monitors CPR actions is a really good idea too for the same reason. Even with training, in the moment you can get it wrong. Thanks for this. It was fascinating!

[@PaulG.x]

The CPR doesn't restart the heart. It should automatically restart. If it doesn't CPR needs to continue , unless the reason the heart is not restarting is because the patient is dead. CPR just keeps the blood flowing and oxygenated.

[@michaelcherry8952]

@@PaulG.x I guess I wasn't clear. I meant that hopefully the heart will restart and the patient will recover because of CPR (which the machine also monitors) not that CPR will restart the heart. I'll edit my original comment to remove the CPR reference since it is confusing. Thanks for pointing that out.

[@PaulG.x]

@@michaelcherry8952 When I do my biannual CPR/First Aid refresher courses, the trainers are always quite emphatic about CPR not restarting the heart. They do that because the people they are training expect that to be the case and when it doesn't happen , they stop doing chest compressions. They want first aiders to keep doing chest compressions until an EMT takes over or tells them to stop. The misinformed expectation comes from TV and Hollywood - a couple of compressions , the patient coughs and jumps up and continues his triathlon. 🙄

[@ragetist]

This is really interesting. I was under the (probably common) misconception that defibrillators somehow shock the heart back into action instead of rebooting it. The ultimate "have you tried turning it off and on again?"

[@IndiTheBull]

We've just replaced all the old as hell heartstart defibs with Zoll ones so it's super interesting to see what's inside these things.

[@IndiTheBull]

I wonder if the reason our NHS Trust replaced all the heartstarts specifically with Zoll was down to the ease of maintaining them. The pressure sensor is an amazing idea but my god does it knack the heel of your palm after a few rounds.

[@bigclivedotcom]

It was probably to reduce long term costs and the maintenance required.

[@12799MaDeuce]

Had a Zoll kit at my previous workplace. The training from the distributor was extremely thorough, the talking instructions were super helpful if you hadn't had any training, and I was overall incredibly impressed with the quality of their product. I hope to work for myself one day, and I'll definitely be carrying a Zoll AED in my work vehicle.

[@BongoBaggins]

I've been on the receiving end of one of these. It was used to stop my heart when I was having a heart attack in the catheter lab in Wythenshawe University Hospital. It took 8 minutes to get my heart going again though. It's very good at its job.

[@restorer19]

It's probably worth mentioning that a defibrillator is (or harmful) - and will refuse to apply a shock - during a heart attack (myocardial infarction) rather than an electric-based irregular heartbeat (cardiac arrhythmia). Since a heart attack is a circulatory issue resulting in local lack of blood flow to heart muscle, stopping the heart briefly is probably the last thing you want to do. Certain arrhythmias can cause heart attack-like symptoms, particularly angina, but without preexisting near-complete blockage of a coronary artery, it's not much likely than intense exercise to cause heart muscle damage. Some training classes, for lifeguards for example, will have simulated "quizzes" where one student or TA will act as though they're having heart problems, and one or more students must act quickly with the appropriate first aid or response. Some volunteers took great joy in simulating exaggerated, Shakespearian deaths from defribrillating a heart attack. I presume this was before the more intelligent defibrillators were common.

[@mxslick50]

The metal enclosure is most likely an accelerometer to detect the movements of the compressions. It also helps in counting the compressions.

[@gn_electronics]

That was my first thought!

[@AlexRian_]

That assumption is correct. Maybe it's one of the Analog Devices ADXL or similar series of sensors.

[@kc8ufv]

The pads with that sensor in the middle are definitely to provide CPR Feedback/coaching. Proper depth and rhythm are critical. With that sensor, the monitoring in the unit can tell you if you need to go deeper/harder, or tell you if you are slowing down. While Clive didn't connect it in a way for it to do so, most, if not all, AEDs will give an audible metronome to assist with the pacing of CPR.

[@Paxmax]

I think so too, looks alot like the accelerometers used in early quadcopter controller boards.

[@JuanCarlosCoreaBarrios]

That is a fascinating look at the inside of a device I've used quite a few times ( thankfully on the giving end of it). I may be able to give a few details on the design of the board and electrode pads (I'm a doctor with an interest in tinkering with stuff, not an engineer, so please excuse my lack of electronics technical knowledge). The divider section is there to control the power output to the pads, as the device will recognize different shockable rhythms, which can be resynchronized at different outputs, not just ventricular fibrillation. The necessary energy to convert said rhythm can vary from 25 joules for some atrial originated rhythms to 200 joules for ventricular fibrillation ( or 360 joules for the older monophasic devices). That pressure sensor does not only measure the strength of the chest compressions, it will most likely prevent the device from analyzing the rhythm during CPR, as the chest compressions can sometimes mimic a true heart rate, and will prevent the device from discharging if the patient is not clear to prevent shocking the rescuer with potentially disastrous consequences. The analysis circuitry has to be isolated to allow the heart activity to be read since the average voltage of the heart activity is usually 1 to 2 millivolts at the surface of the chest, and I'll guess there is some sophisticated filtering going on to remove interference from muscle activity, other devices and such. The pad design is such that the right shoulder pad is the negative electrode and the left lower pad is the positive one and goes over the typical position of the apex of the heart. This is because the direction of current flow in the heart muscle goes from right to left and from the base to the apex, and shocking the heart in reverse polarity will invariably worsen the situation. Also, for rhythm analysis the device would need to know where it is looking at, and this electrode position is the one known as ECG lead II which is usually used for monitoring as it will sense the largest waveform and make recognition easier. BTW, babies do explode rather frequently, that's why nappies exist😂.

[@phils4634]

In Australia, you can buy a "personal" single-use, almost pocket - sized "in home" defib. for around $300. Extremely simple and straightforward to use, with definitely "no frills" such as an LC display, and you can even have a "lease" arrangement where you pay a monthly fee (with replacement if used, and after five years' non-use). These are appearing in many taxis, and are certainly present in all Police and Fire Service vehicles for immediate resus. use. Nowadays, most Pharmacies (including The Wife's) have an AED (hers is a Zoll AED Pro, which is certified for ACLS use), with a lot of Professional effort to reach 100% Pharmacy ownership, especially in rural areas, in the form of substantial grants, since such "upmarket" machines are a lot more costly (around the $4000 mark).

[@ragetist]

In US it's probably best to cause a scene, get tased by the police and hope for the best instead of seeking medical help and get millions in debt.

[@SeanBZA]

Definitely a government sponsered program then, likely with your health service running it under a tight leash.

[@MrDuncl]

I read that Australian. Kerry Packer was a big supporter of Defibrillators having been saved by one.

[@nickloh912]

I can tell how excited you were while you explained how this worked and the history - and rightfully so, medical equipment is fascinating. During the lockdowns I read up on the various makes and models of ventilators (since they were in the news so frequently) and now every so often I think about getting an old out-of-service one and tearing it down to see how it worked...

[@retro_tech]

Fantastic video, Clive. Every time I see such a complicated device built for a noble cause like this one, it really hits me how far we've come as a species and how much we can achieve by working together towards a common goal. Truly amazing.

[@rustymotor]

Have worked in Biomedical engineering since the early 80’s and have seen the evolution of Defibs from heavy devices sitting on stainless steel trolleys with the green CRT displays and traditional curly cord paddles and right through to the modern AED units such as this ZOLL unit that is easily carried around. The old units were great to dismantle for high quality components and the storage capacitor used to be very large and possibly containing dreaded PCB oil. Yes, the old fashion defibs could be used to zap things with as there were no computerised safety lockouts to prevent accidental discharging of 360 Joules of high voltage into empty drink cans or disused electronic circuit boards. Good fun to be had back in the day with old defibs!

[@phils4634]

Back in the day (when I worked for the Royal Navy in Nuclear Medicine), we built a Marx generator using date - expired defib. capacitors. That cap (if charged to the target 2.3kV) is good for just over 300J. Our Marx gen. was quite capable of producing VERY energetic 1 metre sparks, and used to get through 10 megohm resistors at quite a rate!

[@conundrum2007]

Interesting, I came up with a project, making a giant induction heater for nuking hard drives. The idea is basically to get the drive hot enough that any possible data is long gone (red heat) with a video camera to show that the drive has actually been destroyed prior to shredding.

[@125brat]

As a long-term sufferer of paroxysmal atrial fibrillation I have been successfully d.c. cardioverted many times in the past. As i understand it from the way the heart works, it is the only organ in the body that works independently and autonomously from the brain- as long as it is provided with oxygenated blood, it will beat and pump. Cardioversion in fact stops the heart and hopefully allows it to restart under the control of the sino-atrial node which is it's inbuilt pacemaker. The rhythmical beating is a contraction and reset of the chambers seen in the qrs complex waveform but this is initiated by the p-wave which is a vey small hump seen just before the qrs complex. Absense of the p-wave causes chaotic and random firing of the contraction process and the irregular rhythm characteristic of AF. Of course there are many other issues with the heart that may or may not be resolved by cardioversion, so this is why careful analysis of the hear electrical activity prior to shocking is done otherwise it can be ineffective or damage to the heart.

[@drmatt89]

A.E.Ds most of the time do not have a cardioversion option (unless fancy ones that can be put into manual mode). DC Cardioversion is slightly different to defibrillation, uses less energy and it is synchronised to a certain point in your cardiac electrical cycle. Defibrillation just dumps all that energy in one go as soon as you press the button, if you did that when in AF it may turn into Ventricular fibrillation. i.e put you into cardiac arrest. You are correct in that heart will keep beating with oxygenated blood. The brain modulates the speed and force of contraction with nervous and chemical control. Hope your experience with cardioversion was ok. Source : FRCA FFICM

[@PaulG.x]

I used to work in the physiology department of Green Lane Hospital which had an international reputation for cardiology research. One of the projects I recall was researching cardiac perfusion methods for transporting hearts destined for transplant. They used rat hearts and would keep them beating for quite a long time after removal from the animal by just supplying them with a perfusion solution instead of blood. The organ was then rapidly frozen and analysed to determine if any deterioration had occurred during the process. en.wikipedia.org/wiki/Green_Lane_Hospital,_Auckland#Legacy

[@125brat]

@@PaulG.x That's interesting. Back in 2008 my wife and I landed in Christchurch after 34 hours of flights from Heathrow via Los Angeles and Auckland, only for me to go into atrial fibrillation during the night. My wife contacted the hotel reception and I was subsequently taken to the hospital in Christchurch for treatment. We were seen by an Irish doctor who on learning we were on holiday arranged for immediate cardioversion "so we could get on and enjoy our holiday". A couple of hours later I awoke to find I was back in sinus rhythm and after a cup of tea was on my way back to the hotel to continue a fantastic month-long tour of south island in our Kea motor home. It's a holiday my wife and I will never forget for many reasons, not least the fantastic care from the doctors and staff in the Christchurch hospital.

[@PaulG.x]

@@125brat I frequently visit the laboratory complex Christchurch across the road from the hospital . I was there the day of the big earthquake in 2010.

[@125brat]

@@PaulG.x We were very sad when we heard about the earthquake and that the cathedral had been basically demolished as well as other places we'd visited. We were shocked to see the pictures of the devastation to the coast road north of Kaikoura we had driven along during our visit and the many other places that had been badly damaged. Unfortunately it's the price of living in a geological very young country.

[@jkobain]

When Clive pays so much attention to how something is made, makes you want to buy it, ngl. ;D

[@guitarslinger4hire]

Been a medic for almost 35 years now. Ive given the shocks 100s of times and been on the receiving end of 7 (thankfully i was dead for those). The heart actually puts out millivolts that can be picked up with an oscilloscope, and the first monitors were nothing more, but with filters to remove interference. I think some of that circuitry may be a flip/flop for lack of better terms because the initial charge is delivered from one pad to the other, then it reverses and goes in the opposite direction, these are referred to as bi-phasic. The old ones basically just charged the capacitor, then dumped the entire charge in one direction. Good video, as a provider, we dont get to see the insides of those often.

[@John_Ridley]

$1000 for a defib is a killer deal. I bought one for a public space as a donation about 15 years ago, and with a deep charity discount it was $1500, I think list price was around $2500.

[@oliverer3]

Does kinda seem like the type of thing where you probably don't want to go for the cheap bootleg version.

[@benbaselet2026]

@@oliverer3 This just made me think if there are actually cheap chinese copies of these things in aliexpress... Of course there are Chinese versions of the things but hopefully not fakes of other products.

[@oliverer3]

@@benbaselet2026 A cursory search found fewer than I expected but there were definitely some for very concerningly low prices.

[@ShockValue500]

Automated defibrillator prices have dropped dramatically the past couple decades. One of the first automated units cost 5000 in 1985, then the first biphasic AED cost 4000 in 1994, and nowadays the most advanced defibrillators cost only 2000 in today's money

[@benbaselet2026]

@@ShockValue500 Probably they are fairly cheap to manufacture en masse. Medical certification probably has its costs and when the buyers are all kinds of companies, public operators and other non-individuals there is no point saving a couple of hundred bucks on a unit because many just don't care.

[@RetroTechRestoration]

I've been a paramedic for 20 years. Most of the new AEDs support biphasic defibrillaton, part of which is measuring the resistance across the pads and only delivering an appropriate amount of current. The chain of resistors may be used for part of that adjustment.

[@jednick]

This is like seeing an old friend. I outfitted my former police department with the Zoll some years ago. It replaced a competitor model that aged-out. The Zoll used standard batteries instead of a proprietary battery cartridge like the previous one. The one-piece pad is easier to work with, too. Excellent unit.

[@CameraTim-DAMMITDOTcom]

I'm now imagining a defib unit with a "is the patient a lawyer?" button on it. We were taught how to do CPR back in the late 1970s, probably in the boy scouts. I remember being told you'd have to apply enough pressure to seriously dent a very hard basketball. That's not easy to do. In the last 5 years when mum was in hospital (with dementia and probably had a stroke) a nurse was saying you'll probably crack ribs giving someone CPR. Don't stop, keep going.

[@gregorythomas333]

In the US we have Good Samaritan laws that protect people that attempt to render aid to someone...they cannot be sued for either for saving them or failing to save them. I looked up these defib units and in the US they run about $1400...but there are refurbished units available that go for only $800....so they are definitely affordable if you save up.

[@deker0954]

You can be sued. In wich case you need a lawyer. But the case is unlikely to go forward.

[@CountryRock2k1]

@@deker0954 Perhaps if the patient has a DNR.

[@themanhimself3]

@@CountryRock2k1 Could you imagine actually saving someone's life and they have a DNR? It sounds like a movie script. 🤣🤣 I'm sure you would be fine because DNR's are usually protected by HIPAA, there is no way you could know.

[@The0Meerkat]

The X and tick arn't just for battery. A tick indicates that the unit is emergency ready. For this to be the case the following needs to be true: the batteires need to be installed, the batteires need to be in date, a set of pads need to be plugged in and it needs to have passed a self diagnosic check. In the event of a low or expried battery the unit will also make an occasional beep in a similar fashon to a battery operated smoke detector with a low battery. The unit has a built in timer which is reset manually when new batteries are installed. It works on an honour system there is no computerised check. The self diagnostic process runs periodically by itself.

[@echoroommedia]

Whoa! My grandfather was actually on the engineering team ( or lead engineer/designer I can’t remember) for one of the first zoll designs that shrunk these devices down to laptop size! Totally forgot about that

[@joetaylor486]

Our equipment group (UK ambulance service) rate Zoll defibs. We have had a few different ones over the years and a currently using Corpulse units. Previously physiocontrol lifepak 15s

[@jayzo]

Speaking of proprietary batteries - I work with ETDs, devices that are used to detect explosives and the machines are incredibly overpriced. £19k each and the batteries give you an hour of battery life when off the mains supply. Replacements cost about £500 each I think and they're literally 8 18650s with a proprietary BMS and fancy case. I've been saving them from the bin and recycling them because most failures of the battery are actually the BMS so those 8 cells were perfectly good, Panasonic cells too.

[@daviddavidson2357]

Hearing you speak about the infrared port for it to log and communicate with a PC reminds me of one the absolute best implementations I've seen of having a device communicate with another (in this case a phone, over an app), it was a carbon monxide alarm that logged levels, alarm events, severity (yellow or red) and dates. Did it use Bluetooth? Nope. Did it use WiFi? No. Did it use IR? No. NFC? Nope. No superfluous communication parts needed, it used the piezo buzzer (at a relatively low volume) and the mic in a mobile phone, basically like an old modem. It would spend a few seconds chirping while being held close to the phone and that was enough to send the kilobyte (if even that much) of data to the phone. You didn't set the date and time on the alarm itself, it (I assume) just says "This is how long I've been turned on for" to the phone and the phone uses it's time and date to figure out times and dates of alarm events. Very clever system. Another clever one I've seen was when I got a universal remote for my grandmother; she's getting older and two remotes with lots of buttons tended to have her change the input source and not know how to fix it, then get pretty upset over the whole thing. The sale page for the remote said it was programmable, so I assumed that meant that you entered in a code to select ones saved to the memory chip from the factory. You could do that, or you could hold the old remote up against the IR LED ("Within 3-5cm") and then the IR led would be run in reverse (like an IR solar panel) and it would save the information sent. There was only 1 IR LED on it, so it didn't have a specialized photodiode/phototransistor It was a bit hit and miss, usually programmed all but one or two buttons, I ended up using a flipper to program it because of the brighter IR blaster (also allowed me to see if it was saving the remote codes as actual codes, but it was just saving whatever the LED picked up) and got it done on about the fifth try, though I was able to custom select which buttons would be enabled, save both the TV remote and freeview box to it and most importantly avoid programming in stuff like source select so the TV wasn't accidentally changed around. Two clever workarounds to save on part costs and complexity without actually compromising on the function of the product.

[@andymonty2528]

EI "audio link" works great as long as it's quiet... Not just the co alarms their fire detection range uses it too

[@obd6HsN]

12:50 - no, they will still use IR because of the opto-isolation. Same reason that the machines you see on the wall have mains power to light the box and keep it warm, but the AED is completely battery-powered.

[@ruben_balea]

If ElectroBOOM were with you I think there is a 99% chance that he would volunteer to test the ECG function and also a 1% chance that he would be willing to test all the functions.

[@psirvent8]

I mean, testing the ECG function wouldn't cause any harm, and besides, this is a semi-automatic AED, meaning you have to press a button to actually deliver the shock. No button press no shock. Also if the heart is beating as it should the AED will not deliver a shock even if you press the button. Therefore it looks safe enough for anyone to try out.

[@brianm6337]

He could send it him as a birthday present..

[@kc8ufv]

​@@psirvent8While closed up, the unit won't give a person a shock unless they have a rhythm where a shock would be beneficial, such as VFib.

[@SeanBZA]

@@psirvent8 Also it detecting a proper rhythm and normal range heartbeat it will simply refuse to deliver any shock, and removing the pads will also cause it to detect pads off, and still not shock. Most of the smarts has gone into making sure it really will not do anything dangerous, and it has a very narrow range of conditions that are acceptable to do any action, other than tell you to call EMS.

[@psirvent8]

@@SeanBZA Yeah, I knew that too.

[@richardockman8303]

Last Wednesday i had surgery for an implantable cardioverter defibrillator which is made by Abbott and is the model Gallant DR. I now have an App on my phone that downloads the ICD each night and sends the condition of the device and any heart rhythm problems to the Doctors office.Battery life depends if the ICD is pacing often , should be five to nine years.

[@CrazyOregonBeaver]

I used one of those Caps in a bug zapper, with some modifications. No more little dead bug bodies laying around just vaporization. 😂😂😂

[@samuelfellows6923]

And… how loud were the exploding flys? And did you have to further part the electrical bars/grids assuming they would self-arc without a fly across them with the zapper turned on, with a capacitor of that capacity

[@CrazyOregonBeaver]

@@samuelfellows6923 They were quite loud. But not as loud as wasps and large moths.

[@paulmaxwell8851]

We have a bug zapper at our local Community Hall that vaporizes flies. It sounds almost like a small gunshot and everyone jumps. We don't like it!

[@Byzmax]

As someone with my own defibrillator built in to my chest I can attest to how amazing these things are. It's saved my life twice now and also has interevened in a more sophisticated way when it detects a problem starting to reveal itself so it does not have to give you the full shock. It communicates with the hospital any changes in my heart function and they will often know I have a problem before I do. Truly incredible...... The lawyer bit made me laugh quite a bit

[@peter.stimpel]

I somehow LOVE the way you are telling not to safe lawyers, by maneuvering around with may or may not.

[@midlifelab]

I think the only safe way to proceed if the first aid patient is a lawyer, is to get their prior written consent to try and save their life, preferably notarized!

[@peter.stimpel]

@@midlifelab And even then I couldn't be sure not to get sued afterwards.

[@LiquidPortalDigital]

I owe my life to one of those. I went into VFIB while working out, still no cause found after lots of expensive testing, and the EMTs that arrived had to shock me twice with one. I don't remember any of it except waking up 3 days later in the ICU. Amazing piece of engineering.

[@bigclivedotcom]

I recently checked the one in the local gym had up to date pads. I was willing to donate a new set of batteries and pads if they were out of date. They were well in date, so it is being maintained.

[@TopEndSpoonie]

That was so good. Thanks for that Clive. Been wanting to get my hands on one to have a look inside.

[@carlveilleux5744]

Talk about a good timing. I just had an episode of fibrillation last week and ended up at the hospital. When the doctor announced they were going to perform a cardioversion on me, pointed to the defibrillator besides me and started to explain what this was, that didn't sound very enjoyable. I mean, if I'm passed out, go ahead and shock me, but hearing the nurses revising their protocol of what they were about to do and specifically what they were going to do if the procedure crapped out (basically, a 2nd stronger shock) I didn't feel like hearing that! ahah! Miraculously (to me) the problem went away at the very last minute (I had medication). I was literally seconds away from being shocked with the defibrillator, with the electrodes glued to my chest, sedative ready to be injected etc when my heart got back in sync by itself. I know there is a huge killer capacitor in those things, and when they glued the electrodes to my chest that's all I was thinking of!! lol

[@farmersteve129]

The baby remark at around 6:00...😅😅

[@robindeputy]

I work for a utility company here in the USA and we carry these defibrillators on our vehicles and must re-certify on CPR and AED use regularly. I’ve always wondered what they looked like inside. Thanks for sharing!

[@KeritechElectronics]

Damn good video, I loved the in-depth explanation and a reverse teardown :) I never had an AED in my hands, let alone took one apart. It's good to take a peek into one.

[@ziginox]

It's always comedic when a presenter is fighting a device trying to talk over them, especially when it's talking in another language. That has to be one of the biggest modern capacitors I've ever seen! Absolutely massive.

[@karllangeveld6449]

I opened one of the ‘pressure sensors’ similar to this one (a newer version of zoll)and found out it wasn’t a pressure sensor but a 3D accelerometer.

[@bigclivedotcom]

It does appear to be an accelerometer.

[@norr2596]

Yes, they are accelerometers. Zoll used to (maybe 5 years ago I last saw it?) have a training app so you could attach your phone to the back of your hand with an elastic band and monitor compression depth during training on CPR manikins. Generally really useful to get feedback at a stressful time, but can be less than helpful when performing CPR on a small framed individual and the AED keeps exhorting you to press almost all the way through their ribcage to the floor.

[@Aardvarkzombies]

As a CBET, I appreciate sharing knowledge of defibs and AEDs. Good video.

[@dcallan812]

Very interesting thing. I hadn't realised how inexpensive (relatively) they are now. I might even subject we get one for our flats. Most of t he residents are older folk Great video 2x👍

[@256byteram]

A friend of mine many years ago got ahold of a very obsolete defibrillator, somehow. Not sure how. The tag said it was decommissioned in the 1980's and came from a local hospital. The capacitor in the Zoll defibrillator can store a charge of 320 Joules. The unit I remember had a maximum charge in excess of 500 Joules. My dad works in a hospital and I told him about it. He recalled a nurse telling him (and I understand there are few degrees of separation there) there was an incident at a hospital she worked at in the 1980s where a nurse was electrocuted and killed by a defibrillator. It was said to be a loud, blood curdling scream as she was flung across the room. There were two machines in service, and the second one saved her life. Both machines were ordered to be decommissioned and destroyed. I went back to my friend's place and looked at the service tag on his machine. It was the same hospital, and from the same period. He's always accumulated a lot of weird things.

[@o0OMouseO0o]

You should ask Ralphie if he could secretly try it out on one of his clients.

[@tncorgi92]

I had to think for a moment and remember what line of work Ralfy was in, then I chuckled.

[@wisher21uk]

I’ve learnt something new today Clive, I never knew they stop the heart, I always thought it was for restarting the heart thank you 😊

[@drmatt89]

They cause all of the heart muscle cells to depolarise at the same time which then hopefully allows the hearts own pacemaker cells to restart in a more coordinated fashion. They only shock when the heart is in Ventricular fibrillation or ventricular tachycardia, i.e the electrical discharges are random or too fast for the heart to contract and pump normally.

[@wisher21uk]

@@drmatt89 thank you

[@iandennis7836]

​@@drmatt89this.

[@iamdarkyoshi]

You should work with Alec from Technology Connections for a crossover episode. I think a video from him on these would be quite cool

[@rich1051414]

Most people don't know this, but often a heart attack doesn't mean your heart has stopped, but rather, the beat is irregular to the point that it can no longer pump the blood, and the best way to fix that issue is to first stop the heart, and then restart it. Scary stuff.

[@supralapsarian]

We have this same unit at the church where I minister (and am certified on its use). I have always thought it to be an excellent design. Thank you, BC, for showing us the excellent INSIDES as well. The pressure sensor was a great bonus discovery!

[@davidgriffiths2223]

Thanks Big Clive, I needed a visit to the ER today for an encounter with the professional version (which fixed me all up). When I got home I ordered this model. I also love the easy maintenance of this unit without proprietary batteries. Hope I don’t need them but feel better having one for the family at home.

[@3rdworldgarage450]

I work as a Biomed in a hospital and always find it interesting to see the take of people outside my profession on the things we work with every day.

[@wombleway]

Not that there's anything wrong with any of your other videos, but this one is absolutely brilliant - AEDs are an amazing bit of kit, and they're so easy to use by anyone, even a total novice with no first aid knowledge at all. It's great to see someone so enthusiastic about the device, if just one person is inspired to "give it a go" in an emergency situation when they may otherwise have hesitated, then that'll be fabulous. Excellent stuff Clive. 👍🏻

[@rohitkhanna4487]

Talking about defibrillator battery. I had found some old batteries for Defibtech Lifeline in the recycle bin at my organization. I opened the battery which was in a plastic casing. I was anticipating a reasonably sized Lithium chemistry. I was disappointed to find a fairly small Lithium battery with a circuit board that had a RTC chip to keep track of battery expiry date.

[@MeteorMark]

Thank you for the in depth explanation of this AED Clive! As a Beach Lifeguard, Company First Aider (Bedrijfs Hulp Verlener) & Red Cross Telecommunication Technician, I never had to perform CPR or hook up an AED in real life, but have had training on several models over the years, none that shows the steps with the LEDs & pictograms, or speak Norwegian 😉 though. The pad for measuring compression depth & frequency is new to me, I already deducted the component is an accelerometer, pretty neat! And for everyone, if you up to it, learn CPR, with an AED, and basic First Aid. You'll never know when you have to use it, and if you don't, always call for help!

[@BryanTorok]

About 6 years ago I was diagnosed with having atrial fibrillation (AF). After being treated with meds and stabilized, my cardiologist had me back in the hospital for a process called cardioversion. They put a pad on my chest and one on my back and zapped the heart. They had me under anesthesia as I'm told it is quite painful. I had oval burn marks on my chest and back from the procedure. The doctor said it only took one shock to get the heart back in sinus rhythm. I've been fine ever since. I check myself regularly with a Kardia device that shows and records my EKG on my cell phone and the cloud.

[@williamterry3177]

Thank you for your heartwarming analysis! Bless your heart Clive!

[@JerryEricsson]

Mom passed away on New Years day at age 97 and 11 months. She had me execute a DNR on her because a nurse informed her that CPR would break her ribs and she decided she would rather die then live on with broken ribs. She hated pain of any sort, god bless her. When she did die, the nurses were not with her and the subject never came up as it were, they checked on her (she was hospitalized with flu like symptoms) at 4:00 AM, then checked again at 4:20 AM and she had died. Had I known the seriousness of the illness I would have been by her side but the doctors didn't think it was that serious. Doctors don't know that much I guess. Ah well I am getting used to planning funerals, Did my wife 4 years ago, both my sisters before that and my brother-in-law before that. Death is expensive. Well post death is expensive. I have enough insurance to plant me on the hill between mom and my wonderful wife of 51 years and 4 days, my kids can fight it out over my house, I willed my guns to my grandsons, guess I am ready when my time comes.

[@jasonsomerville2504]

When I started as an NHS technician and then Paramedic in the 90s, I used the Lifepack 5, 10, 12 and then Zoll devices. The early life packs had those paddles, and we'd use condutive gel or later wet pads ( we called 'wet fish')...AEDs of course smaller and pads which got rid of paddles. The different pads such as the paediatric ones, have I believe a different impedance which tells the algorithm what modes are appropriate. The relay probably allows the charge to be dumped, if a rhythm changes...really interesting session thanks...

[@ewoutbuhler5217]

Nice! I'm part of the neighborhood 6 minute zone initiative making sure our area is covered by 2 AEDs that are accessible 24/7. It's crucial to be with a patient within 6 minutes after cardiac arrest/fibrillation. The 112 network will issue a call via app to trained volunteers to go to site with a patient requiring CPR/AED, via the AED pickup points, boxes installed on the outside of some neighborhood houses. Just got the service contract renewed, we're good for another 5 years.

[@AnotherGenericChannel]

Been zapped twice in the last year by defibrillators. Been shocked a lot by those since I was 16. The most annoying part is all the tiny burns spread out, bunch of spiky itchy burns that will be around for weeks. The shocks kind of blur together over the decades but those tiny burns will be around for a few weeks to remind you of the shocking experience you had recently. They are a large part of why I only play with low voltage/amperage/mortality rate electronics. Last trip to the ER I was the only patient in it at the time so when they went to do cardioversion the staff asked if they could watch. Ended up with 4 EMT's and over a dozen Nurses and Doctors in the room. Pacemaker only kicks in when it detects fatal rhythms. For some inexplicable reason it is hard to call Emergency when you are getting tased repeatedly. Especially when you are getting tased directly in the heart.

[@stevesmith7530]

As someone in pre-hospital emergency care, AEDs are fantastic. That they can be used by people with no training whatsoever just makes them better Many of the proprietary (£300) batteries are just a bunch of the same or similar lithium cells welded together in a pretty plastic case. Part of the reason to not touch during monitoring is so the machine does not pick up your heart beat.

[@zero0ryn]

Hey Clive, An ECG measurement from Right arm to Left leg will give typically 1mV Peek to peek of signal. Its measured using a balanced deferential amplifier with a 50 or 60Hz filter to block the mains field that we all live in. Often biasing is fed back to the patient via a 3rd electrode. This is usually only required for mains powered devices even though there is isolation between the patient and the rest of the device. I've seen both transformers and opto-isolators used for this purpose. The circuit also needs isolated power which is usually fed through a transformer. A modern 12 lead (10 electrode) ecg does some very cleaver maths in adding and subtracting of multiple analog signals to produce the 12 signals used to diagnose a heart attack amongst other things. I myself suffer from atrial flutter and have escaped being shocked in A&E a few times as the drugs worked :)

[@simrock_]

Not a PSA as such, but about a decade ago when we did our training on them, it used to be that nearly every McDonalds would have one of them in the back or under the counter. So in the unlikely case that you would need to apply your CPR training, and happen to be in the vicinity of a golden arches, and there's multiple of you, it can be worth it to send the other person off and grab one. And yeah, proper CPR will break ribs in most cases.

[@RC-nq7mg]

I think what they were actually doing while rubbing the paddles together was quickly spreading conductive gell over them while the unit charged its capacitors so it could be used the moment it was ready.

[@jamesplotkin4674]

I agree, a notice in bold universal language should clearly state: "Not For Use On Lawyers" Good one, Clive ;-)

[@Alan_AB]

The first ever portable defibrillator was invented in my home town of Belfast, Northern Ireland by Professor Frank Pantridge. The first ever "cardiac ambulance" operated out of the Royal Victoria Hospital in Belfast. Just thought I'd add that in, Clive.

[@mickb6285]

Fascinating! I'm first aider at a civil engineering contractor in the UK and have Zoll AEDs on our construction sites, in vehicles and offices. They have proven be very robust. Often wondered what was inside them, but couldn't find an excuse to go further than swapping batteries.

[@moffarocka3537]

Thanks, Clive, for the insight and background on such an AED. We have used a demo version during first aid training and were told about the rather high energy of the shock delivered, but that capacitor way exceeded my expectations... One thing worth mentioning that we experienced in training: if you are not experienced in regular use with AEDs, like most of us, it may or may not (😊) be a good idea to always have at least another person helping when using the AED. If you are on your own, you may be more than busy with CPR and calling emergency services, and even though the AED guided you through the process, the stress may be immense. Plus, you may lose time locating the next AED and getting it. So another thing I took from the training: make yourself familiar with the locations of first aid equipment and such in your regular places (work, gym...)

[@iandennis7836]

I was a resus training officer and the first thing I hammered into my students was " GET HELP". There are very few worse things than trying to manage a collapsed patient on your own.

[@BY504A]

In the early 80's I worked in a U.S. based company that designed and built defibrillators. It's amazing how small they have gotten the units and how capable they are. The circuit boards at the time were all hand laid out. The batteries were sealed lead acid if memory serves correctly. I was in awe of the people who deigned these devices and often wondered how many lives these machines saved over their intended lifetime. Fascinating topic for sure.

[@ElectronicTonic156]

I took apart one of those a few years ago. Removed the ✅❌ LCD and made a 1-Hz blinky circuit for it. Used a couple of BJT astable multivibrators to make it flash between ✅ in the ON state (AC applied to two middle pins), and ❌ in the OFF state.

[@sjm4306]

That was a fascinating teardown! I work in R&D in the medical device industry and while the stuff we make is quite different it was really interesting to see the design decisions and safety/mitigation measures in this device.

[@Pippy626]

You can change the language with the a flash drive or usb cable using the AED Manager

[@PsRohrbaugh]

Both "paddles" style and open chest defibrillators are still sometimes used in hospitals: a trained medical professional can use hand paddles much faster, and when having thoracic surgery, sometimes defibrillating the person's heart with their chest open is a planned (or unplanned) part of the procedure.

[@AlaskanInsights]

caps like that usually have a resistor built in, but don't bet your life on it.

[@guywilkinson]

It's really nice to see a high quality product being torn down on your channel. It's time we showed people what great engineering is. Thanks for a great video Clive 😊 fascinating!

[@Stuartrusty]

As an electronics engineer/tech who has recently been on a first aid at work course, this is most interesting. Was unaware that some machines had a chest compressions sensor, this is a good idea!