Defibrillators.

[bigclive]

Just in case there's anyone who is still unaware of how these things have evolved over the years, here's a quick insight.

An AED (Automatic External Defibrillator) is an electronic device that is designed to assist in the treatment of individuals who have received a life threatening electric shock. To treat the victim you open the unit (which usually starts talking you through the process) and place the adhesive electrode pads diagonally across the chest as shown in pictures on the pads themselves. The unit then analyses the hearts electrical activity and if it detects a healthy heartbeat it will do nothing other than continue to monitor the hearts operation. If it detects that the heart is in a state of ventricular fibrillation (muscles out of sync) it will attempt to knock the muscles back into sync by applying a high current pulse through the chest at the exact point in time that has the maximum chance of recovering a heartbeat.

The person giving the treatment then provides external CPR (chest compressions) to encourage the heart to beat in sync again.

These things were originally invented to protect the lives of power linemen. (Few of whom actually have access to them!) While they were developing them they discovered that pressure on the chest caused blood flow and CPR was born.

These machines are not the scary monstrosities favoured in TV hospital dramas, but are now the size of a multi-function tester and cost about the same! They are so easy to use that a child can literally use them. they can also be used to recover a heartbeat in the event of other forms of cardiac arrest.

I just thought I'd mention this.... Some areas of the electrical industry involve routine live work and these machines were designed for the men and women who do that work.

Every construction site should have a defibrillator.

Check out Philips Heartstart as an example of a typical unit.

 

[Andy™]

i thought you were going to describe how to DIY one!

 

[exbdc]

Interesting comment Bigclive as I'm actually trained in the use of one.

The major stumbling blocks are the cost of the units, initial training & refresher courses - St. John's Ambulance recommend 6 monthly. There is also the litigation issue. Although an unconscious victim is deemed to have given implied consent & it is difficult to worsen their situation, there have been cases where "ambulance chasers" have encouraged the relatives to sue following a death. It is also recommended that all defib operators are also trained oxygen administrators which invloves further training & access to an O2 kit. These are expensive to buy & also have high ongoing service costs for cylinder testing & O2 cleaning.

Most of us can't put a cost on a life, but unless the HSE regs. change, I suspect they will be few & far between.

 

[bob]

i thought you were going to describe how to DIY one!

i was thinkng exacly the same

bob

 

[Apache]

Now I am going to have to correct a couple of your points there....

An AED (Automatic External Defibrillator) is an electronic device that is designed to assist in the treatment of individuals who have received a life threatening electric shock. To treat the victim you open the unit (which usually starts talking you through the process) and place the adhesive electrode pads diagonally across the chest as shown in pictures on the pads themselves. The unit then analyses the hearts electrical activity and if it detects a healthy heartbeat it will do nothing other than continue to monitor the hearts operation. If it detects that the heart is in a state of ventricular fibrillation (muscles out of sync) it will attempt to knock the muscles back into sync by applying a high current pulse through the chest

You are correct to this point Ventricular fibrillation is really when the heart muscle is fluttering. The muscles are not contracting in a regular pattern, all the cells are firing at the same time.

at the exact point in time that has the maximum chance of recovering a heartbeat.

No it doesn't. It analyses the rhythm. That is all. If it is a suitable rhythm then it delivers a shock. The purpose of that shock is to stop the heart! Seriously. What is then supposed to happen the SAN (sino-atrial node) is the heart's intrinsic pacemaker and the cells should fire here first. If this works well the hearts rhythm is restored. If not the person using the AED must do CPR for 2 minutes before the unit will deliver a second shock and so on until an ambulance arrives, you become to tired to continue CPR, the heart rhythm changes and the machine won't give a shock or the batteries go flat!

The person giving the treatment then provides external CPR (chest compressions) to encourage the heart to beat in sync again.

Ballcocks! CPR is given as soon as the casualty goes into cardiac arrest. It is continued until the AED is available and then the patient is immediately shocked. You may continue with CPR if you don't know if it's worked but this serves as a crude pump to move blood around the body. IT HAS NOTHING TO DO WITH RESTORING RHYTHM

These things were originally invented to protect the lives of power linemen.

That's very interesting. I never knew why they were first developed Thanks

While they were developing them they discovered that pressure on the chest caused blood flow and CPR was born.

Attempts at CPR predate electricity. This cannot be true. :|

These machines are not the scary monstrosities favoured in TV hospital dramas, but are now the size of a multi-function tester and cost about the same! They are so easy to use that a child can literally use them.

Absolutely spot on! You see then in shopping centres and train stations. Cost from

 

[Apache]

Interesting comment Bigclive as I'm actually trained in the use of one. The major stumbling blocks are the cost of the units, initial training & refresher courses - St. John's Ambulance recommend 6 monthly. There is also the litigation issue. Although an unconscious victim is deemed to have given implied consent & it is difficult to worsen their situation, there have been cases where "ambulance chasers" have encouraged the relatives to sue following a death. It is also recommended that all defib operators are also trained oxygen administrators which invloves further training & access to an O2 kit. These are expensive to buy & also have high ongoing service costs for cylinder testing & O2 cleaning.

Most of us can't put a cost on a life, but unless the HSE regs. change, I suspect they will be few & far between.

Some very good point there

Even so if ANYONE was in a situation where a person had a heart attack in front of them and there was an AED available - use it!

They are idiot proof. Open the lid and follow instructions. They will not shock a healthy heart rhythm, nor will they shock a heart that has fully stopped. Only when it is a appropriate. You cannot do any harm.

Oxygen is a useful adjunct but the oxygen MUST be removed from the patient before a shock is given. You guys don't need me to explain that - oxygen + spark = bang!

The person is already dead. You are not going to make things worse - only possibly better!

The time I could see a liability issue was a broken or flat AED provided (not fit for purpose)?

Everyone go and do some first aid training!

 

[exbdc]

Some very good point there Even so if ANYONE was in a situation where a person had a heart attack in front of them and there was an AED available - use it!

They are idiot proof. Open the lid and follow instructions. They will not shock a healthy heart rhythm, nor will they shock a heart that has fully stopped. Only when it is a appropriate. You cannot do any harm.

Oxygen is a useful adjunct but the oxygen MUST be removed from the patient before a shock is given. You guys don't need me to explain that - oxygen + spark = bang!

The person is already dead. You are not going to make things worse - only possibly better!

The time I could see a liability issue was a broken or flat AED provided (not fit for purpose)?

Everyone go and do some first aid training!

So you use them on animals then?

 

[Apache]

So you use them on animals then?

Personally no. They have been used. We had one at college.

A person's heart tends to go into VF whereas animals tend to go asytolic - ie no shockable rhythm.

But I know a little about the theory

 

[Andy™]

Personally no. They have been used. We had one at college.A person's heart tends to go into VF whereas animals tend to go asytolic - ie no shockable rhythm.

But I know a little about the theory

how do you use it to shock a gerbil? each pad would be big enough to wrap it in. but i suppose if it didnt work, he'll be precooked ready for eating...

 

[Apache]

how do you use it to shock a gerbil? each pad would be big enough to wrap it in. but i suppose if it didnt work, he'll be precooked ready for eating...

they have been used in dogs and horses to my knowledge. Someone somewhere will have used one on a cat - I'm sure.

Hospital defibs have extra functions including transcutaneous pacing (forcing the heart to beat when it is beating slow) and cardioversion (changing an arrhythmia to a normal rhythm). These are more likely in a vet context than the shocking of VF after a shock or heart attack.

 

[bigclive]

I think your post is very useful but the factual errors, to me, needed attention

Your corrections are appreciated, but I must admit that I was dumbing it down a bit, using a bit of hard sell to encourage their adoption and completely avoiding the mention of the units actually STOPPING your heart.

The original history is really interesting. The guy who is credited with inventing the technique was approached by the American electrical industry in its early days in a bid to do something about the number of their powerline men who were being electrocuted. A lot of the experiments were done on dogs and initially involved a large high voltage transformer on a trolley which worked on the principle that if the heart was stopped by a shock then another one may get it going again. Latterly the technique was somewhat honed down, but it's only now that defibs are gradually finding their way to the very men they were originally invented for.

During the dog tests it was noted that when the electrode pads were pressed onto the dog, the blood pressure increased and that is apparently the point they "discovered" CPR. Then again, I bet you'll find evidence of similar techniques being used before then, but not necessarily understanding what was happening.

For instance, one technique for "heart failure" was to strap the affected individual over the back of a horse and then set it off galloping. Another completely misguided technique was to use a bellows to blow smoke up the victims rectum. Special bellows were actually made for this very purpose. It's the source of the term "blowing smoke up your ass" meaning to misguide. ROTFWL

I currently have no plans to publish a "make your own defibrillator" project on my website. I feel that might be pushing the liability risk a bit too far.

Given the litigation that has had a negative effect on the adoption of AEDs in some public areas, the only people they should NOT be used on are lawyers.

 

[exbdc]

Given the litigation that has had a negative effect on the adoption of AEDs in some public areas, the only people they should NOT be used on are lawyers.

But didn't Shakespeare say "The first thing we do, let's kill all the lawyers"

 

[Andy™]

I currently have no plans to publish a "make your own defibrillator" project on my website. I feel that might be pushing the liability risk a bit too far.

start watching Mythbusters more. they made one on there a while back

 

[Zeespark]

Apache between you and the Don - I am starting to worry now

AndyGuiness Drink

 

[Apache]

Apache between you and the Don - I am starting to worry now AndyGuiness Drink

Why? What have I said/done?

:|

 

[Zeespark]

You, the chainsaw, being a vet (access to pigs?), and the Don being able to accumulate dead bodies

Only having a pop same to the Don as well :x

AndyGuiness Drink

 

[Robojin]

Given the litigation that has had a negative effect on the adoption of AEDs in some public areas, the only people they should NOT be used on are lawyers.

Very true, we reserve the right to use the 5x RCD 150mA test on them ; \