[HN Gopher] Defibrillation devices save lives using 1k times les...
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Defibrillation devices save lives using 1k times less electricity
Author : wglb
Score : 105 points
Date : 2024-11-06 02:54 UTC (20 hours ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| echoangle wrote:
| > Energy reduction in defibrillation devices is an active area of
| research. While defibrillators are often successful at ending
| dangerous arrhythmias in patients, they are painful and cause
| damage to the cardiac tissue.
|
| I thought this was about needing a smaller battery in
| defibrillators and was wondering if that is really a problem, but
| this makes more sense.
| duskwuff wrote:
| This is more about implanted defibrillators than AEDs. In
| implanted devices, the size of the battery absolutely does
| matter.
| Groxx wrote:
| > _[in an] electrophysiological computer model_
|
| Worth researching perhaps, lower power is much safer for a lot of
| other parts of the body, but is there reason to believe that this
| is correct? Are these models really _that good_?
| Hilift wrote:
| This is actually interesting for multiple reasons. One is the
| technology. The other is the positive outcome rate for cardiac
| arrest after 30 days is so low.
|
| The percentage of cardiac arrest survivors with positive outcomes
| 30 days after release depends on the type of cardiac arrest, and
| can range from 40% to 82%:
|
| In-hospital cardiac arrest (IHCA) The 30-day survival rate for
| IHCA is around 25% in the United States and up to 35% in European
| countries. *In one study, the 30-day survival rate was 40%, with
| 34% of survivors having good neurological outcomes*.
|
| Out-of-hospital cardiac arrest (OHCA) The probability of survival
| after OHCA can be increased by providing immediate
| cardiopulmonary resuscitation (CPR) and using an automated
| external defibrillator (AED). In one study, *10% of people who
| experienced OHCA survived with a favorable neurological outcome*.
|
| https://pmc.ncbi.nlm.nih.gov/articles/PMC8359113/
| dukeofdoom wrote:
| My father survived this. No brain damage. Lived a few more
| years, until 74. The heart wasn't pumping at normal rates
| because of damage. Do to hip problems (arthritis) also had
| problems walking. Eventually Developed a blood clot in a leg.
| Initially survived the blood clot. But the medication given to
| thin out the blood clot caused bleeding on his liver. Somehow
| the Hospital missed the bleeding until it was too late. The
| operating room was also busy (Canada), so no intervention could
| be performed. Wasn't allowed to see him because of covid rules.
| Possibly been able to advocate for him if I was in his room,
| and saw his worsening condition.
|
| They can save your life in a hospital, but just as easily kill
| you by mistake or side effect of whatever intervention they are
| doing. Also, walking (or being able to walk) is very important
| for longevity.
|
| But the speed of the first response of the cardiac arrest is
| what matters. Since the brain is without oxygen. Assuming the
| person makes it to a hospital alive, they'll cool off the body
| to prevent brain damage. For every minute you survive, your
| odds get better.
| tomcam wrote:
| Terribly sorry for you and your father. Heartbreaking.
| elric wrote:
| When I was attending a first aid & CPR class, one of the first
| things the instructor explained was that the chance of
| successful CPR is very, very low, but not attempting CPR
| obviously reduces the odds even more. Not to discourage anyone,
| but rather to prevent us from beating ourselves up over it if
| things didn't go well.
|
| If you don't know CPR, you might want to consider learning.
| Dumble wrote:
| I think by "successful" the instructor meant actually
| restarting the heart and reviving the patient, which is very
| unlikely. Keeping blood moving und preventing/delaying
| neurological damage is the thing the patient will benefit
| from.
| bigmattystyles wrote:
| I was shocked to learn how traumatic properly done CPR is,
| think broken ribs, etc... no wonder so many older doctors
| have DNRs.
| Zak wrote:
| I think a big part of it is that long-term survival rates
| aren't very high. If you need CPR because of an underlying
| illness, you're probably actively dying. If you're an older
| doctor, you probably know it.
|
| CPR has a much better success rate when something like an
| electric shock stops an otherwise-healthy person's heart.
| elric wrote:
| It's usually a good thing that the heart sits inside a
| boney cage. Not so much when you're trying to coax it into
| action.
| KineticLensman wrote:
| Yes when I was CPR'd I got broken ribs. It was the defib
| that brought me round though.
|
| The broken ribs were much more painful than the subsequent
| ICD implant. Although subsequently meeting the people who
| broke my ribs was actually a very happy and positive
| experience.
| MobileVet wrote:
| Our community had one of those horrible situations you hope
| never happens, kid drowning in the pool during end of year
| celebration. The woman that pulled him out and successfully
| revived him with CPR was a doctor, but credited the save to
| her childhood lifeguard CPR training.
|
| Please learn CPR if you can.
| dheera wrote:
| OHCA survivor now with an ICD here. I just want to say I'm
| grateful for this technology and grateful that people still
| work on this and attempt rescue even if only 10% of people
| survive. I'm one of those 10%.
| KineticLensman wrote:
| I survived an out-of-hospital cardiac arrest (previously
| undiagnosed ventricular fibrillation). Luckily I was in a
| building about 20 yards from where they kept the defibrillator,
| and they started CPR within a couple of minutes of me going
| down, with defibrillation as soon as they had got the device
| ready. I was already sitting up and talking when the air
| ambulance arrived but I still got the helicopter ride.
|
| When I had an ICD implanted a few days later the surgical team
| stressed how massively lucky I'd been. They all stopped what
| they were doing and stared at me when the lead person read out
| my case history.
|
| I don't think I had significant neurological issues as a
| result. Perhaps I should check my HN comment history to see if
| my rate of karma accrual changed around the date of the event.
| softgrow wrote:
| The article is about internal defibrillators. External ones are
| still the same as (good grief) 35 years ago (well maybe down from
| 300J to 200J). The only change I've noticed is moving from a gel
| for the pads to a gel pad (which feel like a frog, chuck one in
| your partners bed and let them find it!) which reduced the
| possibility of burning and odd smells in your ambulance.
| Fortunately my sense of smell wasn't great and often had a
| partner who smoked (and was allowed to in the olden days) in the
| ambulance to dull it. You kids don't know how it was having to
| actually manually read the trace instead of all this new-fangled
| automation that guides you through it.
| breezeTrowel wrote:
| I think the biggest change with external defibrillators has
| been placement. It's now front and back instead of two on the
| front.
| wbl wrote:
| I should redo my CPR then. Learned two on the front in high
| school in NJ. But also to read the instructions though I'm
| sure when seconds count you don't.
| AndrewDavis wrote:
| Modern AEDs have voice guidance telling the person what to
| do. So you can follow the instructions as you do it.
|
| Also, you should call the emergency number in your region
| and (at least in Australia) they'll transfer you to someone
| who can coach you through using the defib and performing
| CPR until professional help arrives.
|
| Don't let that stop anyone from getting their CPR up to
| date though. The more experience you have the better
| equipped you'll be if you need to use it
| giantg2 wrote:
| I see AEDs at work. If I have a heart attack, I have no
| confidence in my team being able to use it. I've seen how
| they handle requirements and documentation in stories.
| have_faith wrote:
| > Not sure if we have time for learning CPR in the
| current sprint, let's put it in the backlog
| exe34 wrote:
| was going to say, you need to make sure to open a ticket
| and bring it to the refinement meeting.
| dx034 wrote:
| I just did a training course and for the ones we used it was
| still two on the front. Only for children it's front and
| back.
| KineticLensman wrote:
| Likewise in the UK, two on the front, at least for adults.
| Makes less disruption to CPR if you leave the patient on
| their back.
| h1fra wrote:
| Well I thought it was one in the front and one close to the
| ribs
| extraduder_ire wrote:
| AEDs are an amazing invention and I'm glad to see them dotted
| around the place. Initially in dedicated cabinets mounted to
| walls outdoors, and sometimes in repurposed telephone booths.
| giantg2 wrote:
| I see AEDs hanging on the wall at work. My only real thought
| is if I have a heart attack at work, just let me die. Clearly
| I'm not going to make it to retirement anyways if the stress
| nd stress eating from my job is giving me a heart attack.
| retrac wrote:
| Bit of a false dichotomy: some people survive a heart
| attack without intervention, but suffer crippling injuries
| as a result. It's entirely possible to develop arrhythmia,
| fall into a low-oxygen state where you get brain damage,
| and then have your stupid heart decide to start pumping
| again.
| giantg2 wrote:
| That's fine. At least I'll be too brain damaged to go
| back to that hell hole.
| abfan1127 wrote:
| you could leave now...
| giantg2 wrote:
| Not really. I have a family to support and no real
| alternatives.
| westurner wrote:
| "New defib placement increases chance of surviving heart attack
| by 264%" (2024) https://newatlas.com/medical/defibrillator-
| pads-anterior-pos... :
|
| > _Placing [AED,] defibrillator pads_ on the chest and back,
| _rather than the usual method of putting two on the chest,
| increases the odds of surviving an out-of-hospital cardiac
| arrest by more than two-and-a-half times, according to a new
| study._
|
| "Initial Defibrillator Pad Position and Outcomes for Shockable
| Out-of-Hospital Cardiac Arrest" (2024)
| https://jamanetwork.com/journals/jamanetworkopen/fullarticle...
| devilbunny wrote:
| I know article authors don't write their own headlines, but
| for all who read this: it's about out-of-hospital cardiac
| arrest, which _can_ be caused by a heart attack, but is in no
| way the most likely presentation of a heart attack.
| westurner wrote:
| The AED should measure the rhythms before applying
| defibrillation.
|
| An emergency AED operator doesn't need to make that
| distinction (doesn't need to differentially diagnose a HA
| as a CA) , do they?
|
| You just put the AED pads on the patient and push the
| button if they're having a heart attack.
| westurner wrote:
| (and stand clear such that you are not a conductor to the
| ground or between the pads)
| inlined wrote:
| I teach AED use and both my curriculum and trainer AEDs have
| one pad on the right chest and one on the left side. Is this
| the "two on the chest" method? If so, why have organizations
| not updated their curriculum and tooling?
|
| Should I assume that irrespective of this finding, pads
| should be placed where the AED indicates so that rhythm
| detection works correctly?
| fm2606 wrote:
| As a former firefighter-paramedic of 14 years which I left in
| 2020, our LifePak monitors went up to 360J. We did use self
| adhesive pads and never once did I have any odd smells after
| "welding" someone. We used stacked sequence, starting out at
| 200J, 300J and 360J. Our LifePaks did have AED but very few
| people used that option, so yeah, medics and agencies still
| require to know how to read traces. To know which rhythms to
| shock and which ones not to isn't rocket science, nor are there
| that many. There are only two pulseless rhythms that get
| shocked. There are also a couple of reason to shock conscious
| people with rhythms that does require a bit more training and
| knowing when to give the shock but it isn't all that difficult
| to learn.
|
| Not sure why the "us kids" comment. How come you aren't
| boasting about not wearing gloves and PPE? I've heard about
| "back in the day" how it was a badge of honor to be covered in
| someone else's blood. That shit ain't cool at all, but it does
| occasionally happen where blood does get on unprotected skin,
| it has happened to me.
|
| Did we have to know as much as back in the 70s, 80s and 90s?
| No, not at all but that is advancement and not necessarily
| watering it down.
|
| If I have an out-of-hospital emergency I definitely would want
| street medics and firefighter there for help. I am still
| shocked how often I've seen doctors and nurses loose their shit
| because they aren't use to having to think on their own or they
| don't have a team of 10 or 15 people there to back them up.
| I've seen it in firefighters and medics as well, just not as
| often. Most nurses aren't allowed intubate in a well lit
| hospital room, let alone lying on the asphalt of a highway or
| floor of someones home.
| Johnny555 wrote:
| >Not sure why the "us kids" comment.
|
| >Did we have to know as much as back in the 70s, 80s and 90s?
| No, not at all but that is advancement and not necessarily
| watering it down.
|
| Sounds like you do understand the comment and agree with it,
| but still took offense.
| 8338550bff96 wrote:
| Best of both worlds
| closewith wrote:
| > Did we have to know as much as back in the 70s, 80s and
| 90s? No, not at all but that is advancement and not
| necessarily watering it down.
|
| We need to know much more now than ever before, as the number
| of treatments performed on scene has grown enormously. Not to
| mention survivability is orders of magnitude better.
| FireBeyond wrote:
| > having to actually manually read the trace instead of all
| this new-fangled automation that guides you through it.
|
| I never met a LifePak 12 that did not flag every 12 lead it saw
| as an "Abnormal ECG".
| snapetom wrote:
| They're already commercializing this. I'm due for a new implanted
| defibrillator because of a needed battery change. My current one
| is 5in x 4in. Depending on when I get it, my electrophysiologist
| says next one should be smaller due to a smaller required charge
| to jump start the heart.
| KineticLensman wrote:
| > They're already commercializing this.
|
| My ICD is an Abbott Ellipse VR [0] and is 2 x 2.5 x 0.5 inches
| in size. It doesn't make too much of a bump under my skin. It
| was implanted in 2021 and I don't think was new then.
|
| [0]
| https://www.cardiovascular.abbott/int/en/hcp/products/cardia...
| snapetom wrote:
| Oh, interesting. I haven't looked it up, but I'm probably
| getting another Boston Scientific. Mine was implanted in
| 2018.
| KineticLensman wrote:
| [Edit]
|
| > They're already commercializing this.
|
| Sorry to disappoint, and unfortunately, no. See other comments
| elsewhere. This study is based on a theoretical study of 2D
| simulated tissues. The original paper itself contains the
| disclaimer...
|
| >> _" The approach considered here is impractical - it requires
| an accurate mathematical model of the tissue as well as
| complete knowledge of the state of the tissue at the initial
| time. Furthermore, computation of a defibrillating electrical
| field cannot be performed in real time."_
| snapetom wrote:
| For this study, yes, but the trend of less and less charges
| has been occurring for a few years. There have been numerous
| studies that have happened 3-4 years ago that's even in the
| cituations.
| niemandhier wrote:
| This appears to be a simulation study done in 2d.
|
| Similar results have been observed in 2d simulations for more
| than 20 years, no one had managed to translate them to
| application.
|
| One of the problems is, that 2 d and 3d reaction-diffusion
| systems are very different when it comes to so-called topological
| charge conservation. One can show that interactions of the
| applied electrical field can be described by its influence on the
| topological charges.
|
| In 2d these topological charges are limited to points in 3d they
| form curves.
|
| Points are limited to drifting and colliding, lines can twist,
| self collide, form rings and so on making translating 1d results
| to 3d quite difficult.
| KineticLensman wrote:
| > This appears to be a simulation study done in 2d.
|
| Yes. The paper says
|
| >> _In this study, a simple two-dimensional numerical model of
| atrial tissue containing anatomical heterogeneities - the
| essential ingredient responsible for the emergence of virtual
| electrodes - was used to explore ultra-low-energy
| defibrillation._
|
| > no one had managed to translate them to application.
|
| Yes. The paper itself has the following statements in its
| conclusion:
|
| >> _The approach considered here is impractical - it requires
| an accurate mathematical model of the tissue as well as
| complete knowledge of the state of the tissue at the initial
| time. Furthermore, computation of a defibrillating electrical
| field cannot be performed in real time._
| nyanpasu64 wrote:
| I remember playing with spiral waves using the VIRUS element in
| Powder Game (2), and didn't know that heartbeat disturbances were
| caused by the same patterns on cardiac muscle.
| wizzwizz4 wrote:
| Powder Game: https://dan-ball.jp/en/javagame/dust/
|
| Powder Game 2: https://dan-ball.jp/en/javagame/dust2/
|
| Emoji Simulator: https://ncase.me/sim/?s=bz
| yapyap wrote:
| 1k times, really?
| kleiba wrote:
| The original article has the number 1,000 in its title, why the
| ridiculous change to 1k for hackernews?
|
| As a matter of fact, as it is written right now, it makes little
| sense compared to the article's actual headline.
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