I am starting a new series of blog posts that I’ll call – We need. This is where I will be musing about things the World in a broad sense needs to be a better place. I will not be writing science fiction, but aim to write about what we can achieve soon, with the technology we already have, if we were just a bit more creative and bold.
My first article is about saving human lives with cheap Automated External Defibrillators.
Introduction to cardiac arrest
New cardiopulmonary resuscitation guidelines are out. By convention they are published every 5 years by international societies of experts after all the recent scientific literature is reviewed. Guidelines are then compiled based on the best scientific evidence we have and, where it’s lacking, on expert consensus. Guidelines are basically your manual on how to best save a person who has suffered a cardiac arrest.
Cardiac arrest is a state in which a person’s heart no longer performs its primary job, pumping the blood around the body and to the vital organs, brain included. A person looses consciousness and if nothing is done by others, the death is unquestionable.
Now here comes the catch. Just because the heart has stopped pumping blood, does not mean it’s in complete standstill. If the first electrocardiogram (ECG) of the heart is recorded just after the collapse, most of these hearts will show electrical activity that we consider shockable (as high as 76% of the time). The rest are in non-shockable activity, when the heart truly is in complete standstill.
Heart is a big old muscle. But it also has some internal smarts that help control it, otherwise it would just be sitting there doing nothing. Its pacemaker cells send electrical signals in regular intervals to the muscle triggering it to squeeze. So the spread of these electrical signals is what we see as ECG when we put electrodes on the patient’s skin.
If these signals are fine, the heart will squeeze fine. If the signals are bad, the heart will squeeze bad. One such bad signal is called ventricular fibrillation (VF). It is a chaotic signal, without any rhythm, that sends the heart muscle in perpetual shivering like motion where it is just wriggling like a can of worms doing nothing to pump the blood. This is the type of electrical activity that many hearts go into at the early stage of cardiac arrest. The good thing about it is that we have a good chance of restoring the normal electrical activity if we shock the heart, something called defibrillation. Think of it like force rebooting a computer that just froze on you.
Open surgery video showing the heart in VF successfully shocked back to normal rhythm.
Sure you could shock a heart in any electrical activity, but the reason one is called shockable and the other non-shockable is based on the response. Shockable activity can be “erased” by defibrillation and therefor the person potentially saved, allowing the normal pacemakers in the heart to start doing their job again. On the other hand you can defibrillate the non-shockable activity all you want, but this will not restart the heart. So basically those patients who are in VF have a better chance of survival. But if they are not defibrillated quickly, they will also deteriorate to a non-shockable activity, usually asystole, drastically limiting their chances of survival. Defibrillation within 3–5 min of collapse can produce survival rates as high as 50–70%.
How to defibrillate quickly
We have seen that defibrillating quickly increases chances of survival. Because the quicker you try this intervention, more people will be in a shockable activity and more will be converted to normal rhythm. Also they will spend less time in cardiac arrest, so their vital organs will not sustain significant damage. When a defibrillator is not available chest compressions and rescue breaths (CPR) are used to take over the heart’s function and keep organs viable until the defibrillator or other interventions are available. However with every second passing this inevitably reduces the chances of survival and good outcome.
So what needs to happen for somebody in cardiac arrest to be defibrillated quickly?
- Witness the collapse
Somebody needs to see that the person has collapsed or that they’re unresponsive and not breathing. People who have suffered cardiac arrest cannot help themselves. Sure, there is a lot that can be done in terms of education to prevent the arrest from happening in the first place. For example, education about heart attack symptoms, such as chest pain and breathlessness. Because if people seek help with such symptoms immediately, many arrests can be avoided. But also on the other hand many arrests come without any significant warning symptoms.There is also a group of people who really do not need anyone to save them, because the saviour is within them. I am talking about people with implanted pacemakers that can also act as defibrillators. These devices are implanted in people who have for example survived cardiac arrest or have been found to have other heart problems in order to prevent or treat potential arrhythmias in the future.
Take a look at this video in which a soccer player collapses on the pitch and is then successfully defibrillated and brought back to life by his implantable cardioverter defibrillator (ICD).
Maybe in the distant future we will all be injected with special nano particles or implanted with small bio chips that will closely monitor and fix our hearts as required, but until then in most cases of cardiac arrest the number one necessity is to witness the event.
- Recognise cardiac arrest
Witnessing someone collapse does not mean you will realise they are in cardiac arrest. This is actually quite challenging for layman. You need to figure out if the person is responsive, but also if they are breathing or not. In the state of fear and if you have not been trained this becomes increasingly difficult. The fine border can sometimes be a challenge even for medical professionals, so if in doubt in most cases it is better to start resuscitation. Of course education is very important here, and luckily we live in the age were learning something new has never been easier. Many strategies can be employed here, and one of them involves smartphones, the most ubiquitous electronic devices that everyone seams to be carrying in their pockets all of the time. They can serve as your assistants if you ever witness someone collapsing.
If you haven’t already, download the free mobile CRP app to help you save a life in the event of cardiac arrest.
Emergency medical dispatchers, the ones you call to send you an ambulance, can also struggle to recognise cardiac arrest based on your description of the situation. This too can be helped with modern smartphones. If you read my review paper on mobile technology in cardiac arrest, you’ll see that for example their ability to make video calls can be helpful.
- Apply the AED
Now that we have recognised the person in front of us is in cardiac arrest, we know the best chance to save them is quick defibrillation.
What the hell is a defibrillator?
A defibrillator is an electronic device that can record an ECG trace of the heart and also deliver electrical therapy in the form of a shock that can stop arrhytmias and allow the heart to restart.
Professionals, like paramedics, carry manual defibrillators like the one below. These devices are very advanced and have many additional features.
Automated external defibrillators (AEDs) on the other hand are more simplified and easier to use versions of manual defibrillators. Nevertheless they are more than capable to do the job. But the best thing is they can do it automatically by diagnosing the underlying heart electrical activity and delivering electric shock if necessary. All you have to do is place a pair of pads on the person’s skin.
OK, now you know what a defibrillator is, but where do you get one in the time of need?
Ambulance crews will have one, so they are always a safe bet. But they are not on scene. It will take them time to arrive. Even in the best systems they will rarely arrive in those first 5 minutes.
Other alternative strategies have also been successfully implemented to augment the ambulance service. For example equipping police cars and fire truck with AEDs so that the network is denser and the ones who are the closest can react. The same principle is used with community volunteers. Trained people who can stop what they’re doing and run to the rescue of those in need. Some very cool strategies are in use here, such as again use of mobile technology to map locations of cardiac arrest victims and rescuers. Just take a look at the fantastic PulsePoint project.
Get a public access AED
Public access AEDs are the ones that are strategically placed in public places that have a high density of citizens, such as airports, railway stations, bus terminals, sport facilities, shopping malls, offices and casinos. Chances are higher that cardiac arrest will happen in the areas where there is a greater flow of people. The problem is that there is not enough of them, so maybe you will just not be able to find one when you need it. The second problem is that even if there is one, you might not know it exists, so it could remain unused. Again mobile technology to the rescue here, mostly with online databases of public access defibrillators with their precise locations.
But the far BIGGEST problem with public access AEDs is that more than 80% of cardiac arrests happen at home. So if you do not happen to live in a shopping mall, chances are slim that there is going to be an AED close by.
Have an AED delivered to you
Maybe in the near future after you inform the emergency medical dispatcher about cardiac arrest over your mobile phone, they’ll drop an AED from the sky at your precise location. You see, it has been proposed that drones could deliver AEDs to scenes of cardiac arrest. Take a look at the ambulance drone project by Delft University of Technology.
Drones seam like a good idea for delivering things. And there are many interesting ongoing projects, like delivering medication to remote villages or delivering your Amazon purchases. Being a geek and loving drones, I was immediately drawn to this idea, but I am not entirely sure it would be beneficial. All the deliveries that have so far been tested and found to be successful were of things that do not require such urgency as AEDs do. While you would be amazed if your Amazon package was delivered in 4 hours instead of 24, this would be no good in cardiac arrest. There are many factors at play here.
Aircraft factors: drone needs to be super fast, super precise, be able to carry weight, have enough flight time, be autonomous, etc.
Airspace factors: weather conditions, ground configuration, but most importantly legislation.
And finally the crucial thing, cardiac arrest factors, the urgency of it, the location which is mostly indoors, etc.
I think the problem is finding a sweet spot where this strategy makes sense. If you are too remote, it probably does not, because it would take the drone a lot of time to reach you. It would be better to own an AED then, individual or at least one in the community. If you are too close to a public access AED, then again why use a drone. If you are within an easy reach of ambulances, it is a question how much faster, if at all, drone can reach you.
While it looks like a good idea, it is still not possible, it would cost significant amount of money, and I am not sure if it makes sense at all.
What I think can happen sooner and be more effective is making…
Cheap as chips AEDs
Let’s compare fires to cardiac arrest, and fire extinguishers to AEDs.
During the last 5 years on average about 6 people per million inhabitants of the United Kingdom per year lost their lives due to fires. In total that is about 400 people per year. On the other hand medical professionals respond to about 30,000 out-of-hospital cardiac arrests in the UK every year and the survival rate is as low as 10%. That means around 27,000 people die from cardiac arrest per year.
Why are fire deaths so rare? I don’t know.
Education? Probably. Better buildings/materials? Probably. Fire alarms? Probably. Legislation? Probably. Better industrial standards? Probably. Reduced use of open fire? Probably. Fire extinguishers are cheap as chips and enforced by law? Hmmm, maybe yeah. It seams that we have been doing most of these things in the cardiac arrest arena, except making our tools cheaper.
By the way, the 10% survival in the UK is miserable. There are some parts of the World, like King County in the USA, that report survival above 60%. They sure did not get there over night, and there are many contributing factors why they are approaching the maximal theoretical survival rate, but the most important one is quick defibrillation. Could the rest of us catch up with them if AEDs were everywhere?
We need to have more AEDs and they need to be everywhere. The fact they are expensive sure doesn’t help. Many studies looking at cost effectiveness of public access programs and personal AEDs concluded that it is just not worth it. Why? Because of the price.
AEDs are unfortunately expensive and their prices are not falling quickly enough for my taste.
I did a bit of research online, and the cheapest AED I found in the UK was 715 GBP (around 1100 USD). Quite a lot. And the prices of subsequent models rapidly double and triple.
The cheapest AED I could find on the UK market. Price without taxes – 595 pounds, 715 pounds with taxes.
Something is fishy here. Why do these things cost so much?
I mean you can buy an amazing smartphone for less than 200 pounds without contract, not to mention one tablet per child 7-inch tablet for less than 80 USD. Modern mobile devices have many times the processing power of the computers that NASA used to get us to the Moon. They feature most of the components that can be found in an AED, microprocessors and Lithium battery, and many others like cameras, various sensors etc. It seams as microprocessors and lithium batteries are getting cheaper, mobile devices are getting more powerful and cheaper as well, but not AEDs.
The basic design of a external defibrillator includes a control box, a power source, delivery electrodes, cables, microelectronics and connectors. Let’s take a look at price trends during the years of two major components, batteries and microprocessors.
Source – Battery University
We can clearly see that over the course of the last 25 years, Lithium ion batteries are rapidly getting cheeper, while at the same time storing more punch. Of course the same is happening with microprocessors. You’ve heard of Moore’s law, right? This all means that the prices of AEDs should have demonstrated the same downward trend? Not to mention the fact that the market is getting bigger, that there is more competition in both manufacturing and sales…
So during the last 5 years, the price of Li-ion batteries has gone down about 35%. What happened with AEDs?
|ZOLL AED Plus||2.270||1.800||20|
|ZOLL AED PRO||3.400||3.000||12|
Prices for 2010 – pdf catalog from that year. Prices for 2015 – Google best price online.
So we can see that the average drop in AED price is about 15%. Far less then the price drop of Li-ion batteries. Crazy!
That ZOLL AED Plus model for example uses a pack of 10 Duracell non rechargeable batteries that I can now find online for only 35 USD! And they were 75 USD just recently. WOW. Batteries are 35 USD, so what costs the extra 1.765 USD in 2015? Not sure, since this model has been around for ages, and has not seen much change, if any. So it is still using the same components as it was 5 years ago, but has not seen a significant decline in price.
AEDs can be cheaper. I am sure.
Not to mention the fact that many of these models are just an overkill for what we want to do. They can deliver up to 300 shocks, have standby times of 5 years, are drop and water resistant etc. In my view this is not necessary for the revolution that needs to happen. Sure, these devices have their place, but for average layman resuscitation they are just too elaborate. I want an AED that can deliver 10 shocks max, because by that time the ambulance crew will arrive, and also the chances of survival are anyway very low if the normal rhythm has not been established by then, that has a shorter shelf life and that maybe can even be a single use device. So strip all the bells and whistles and make something that gets the job done 99% of the time for the price of less than 200 USD. This way AEDs could be everywhere, in every building, in every first aid kit, and in every home with inhabitants with even the slightest risk of cardiac arrest.
Let’s do it!
Latest posts by Ivor Kovic (see all)
- Can tablets replace AED trainers? - October 16, 2016
- Twitterverse of Emergency Physicians – Infographic - January 11, 2016
- Prescribe an app for your anxious patient - December 14, 2015