Carrying a defibrillator?

[tazzle]

I remember a previous thread questioning whether carrying a defibrillator on board for an elderly crew member was a good idea or not. Having just had an email invitation to buy the new Philips HeartStart Home Defibrillator for £600 (why me? Do they know something I don't?) I found the following from an American doc that may be useful to anyone considering this bit of kit:
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1) THE FACTS

These are the statistics you should know before believing any commentator on this opinion board. They are taken from the very authoritative "ACLS - Principles and Practice" of the American Heart Association, p 93, a highly recommended reading.
Rates of survival to hospital discharge for patients with witnessed ventricular fibrillation arrest:
No CPR, delayed defribillation (>10 minutes): 0-2% survive
Early CPR, Delayed defibrillation (>10 mn): 2-8% survive
Early CPR, Early defibrillation (7 mn): 20% survive
Early CPR, Very early defibrillation (4 mn): 30% survive
Public access defibrillation programs in airports and casinos have been able to break the 2 minutes to 1st shock barrier with survival rate of 50-70%
In supervised setting with extremely early defibrillation, 89% survive (based of 101 victims)
Nearly all neuroloogically intact survivors who in some studies number more than 90% had a ventricular tachyarrhythmia that was treated by early defibrillation.

Now ask yourself this: how long, realistically, do you think it would take:
1) for an ambulance (assuming the one closest to you is available at the time of calling) will reach your house, assuming no traffic and no difficulty finding your home
2) for the personnel to carry their equipment, introduce themselves, go to the room where the patient is
3) reevaluate the situation themselves, before, finally
4) decide to install the defibrillator and defibrille ?
(I live in a place in the country where it is not realistic to have an ambulance ARRIVE at my home in less than 20 mn under the best condition (at night with zero traffic), so in my case probability of survival to sudden cardiac arrest at home realistically is nil)

2) THE RISKS

Ok, a defibrillator might be useful if you have a ventricular fibrillation. But, what are the chance of you having one ?

(From Harrison's Principle of Internal Medicine, p 1618)

Sudden Cardiac Arrest probability:
Adolescent and young adults: 1/100,000
between 45 and 75 years: 1/750 (unselected population)

Male are 7x as likely to female to have a sudden cardiac arrest.

% of suddent cardiac arrest due to ventricular fibrillation: 65-80%

When all factored in, for an unselected male 45 to 75 the probability of ventricular fibrillation per year is somewhere near 0.08%.

For your defibrillator to be of any use, you would need all that your cardiac arrest due to a ventricular fibrillation occurs:
1) when you are not sleeping (about 1/3 chance)
2) when your defibrillator is nearby (? chance)
3) when someone is actually witnessing your cardiac arrest (1/2 ?)
4) and that witness knows a defibrillator is nearby, will think of using it, and knows how to use it (?)

Your probability of successful use is probably going down to 0.01% after all this.

Your altruism might crank it up to 0.03% to take into account middle-aged visitors and members of your family your defibrillator will help

THE COST

Now we can determine the cost per life saved:

Cost of machine per year (assuming 10 year depreciation) / (Probability per year of event (middle aged) x optimistic survival rate or 80%) (assuming the alternative is close to 0% survival)

$150 / 0.03% = $500,000 per male life saved


OTHER WAY TO CALCULATE IT

200,000 sudden cardiac arrest in the USA

Assuming every citizen out of 4 in the USA (250M/4) has a defibrillator ($1500/10 year depreciation=$150) (62.5M x $150= about $10,000M total cost) and that 1/10 cardiac arrest will be saved because 1/10 cardiac arrest will fullfill all the successfull condition (ventricular fibrillation, occurs while awake, near a knowledgeable adult, near a defibrillator, not in a car while driving, etc) then the cost per life saved would be: $10,000 Millions / (200,000 * 1/10) = $500,000 per life saved per year.

While I do see the usefulness and cost-effectiveness of the product for airports and other such public area, I am of the opinion that it is not cost effective for the average family.

A much more cost-effectively way to increase your longevity is simply to alter your diet.

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[Colin_S]

[ QUOTE ]
why me? Do they know something I don't

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They did but your article now makes it common knowledge. See the last number.

"Assuming every citizen out of 4 in the USA (250M/4) has a defibrillator ($1500/10 year depreciation=$150) (62.5M x $150= about $10,000M total cost)"

 

[dralex]

I was questioning it when the costs were higher- £600 seems a lot more reasonable. Interesting set of statistics and emphasises the difference between perceived risk and actual risk. A lot of ideas and items are peddled on public perceived risk which is very emotive and over-estimating than actual risk.

I would be interested in knowing the actual odds of using an EPIRB or you liferaft as the cost of the defib is now in the realms of other safety equipment we carry.

ANyone have the figures?

VF arrest in the older population is often secondary to other heart disease, therefore therefore even if you save someone form the immediate risk of death from VF, there may well be other pathology underlying it. It's different in people who are in VF due to other causes such as drowning and hypothermia, as the cause is potentially totally reversible.

If a person does have a VF arrest and is shocked out of it, they are usually still very unwell and in need of acute intensive medical support to maximise their chances of quality survival, but at least they HAVE a chance.

 

[Cutter]

much better you buy a cardioscan device - see what your risk is and modify diet etc accordingly - only a little plug as my mate has the franchise on them in UK but look good and not expensive

 

[Ships_Cat]

I would be interested in knowing the actual odds of using an EPIRB or your liferaft

I would be quite sure that the odds are very, very low. The chance of using the EPIRB being higher than the need for the liferaft.

Here in NZ I would be very hard pressed to recall any occasion in recent years where the crew of a pleasure yacht have ended up in their liferaft when sailing coastal, although I do recall the use of EPIRB's.

On the route from here to the Pacific Islands there are frequently a number of boats lost in a year and of those with 406 EPIRB's (NZ registered yachts are required to carry them for ocean voyages, but very few NZ yachts are lost here these days, mostly foreign) I can only recall very few over recent years who have ended up in their liferafts as well - they are usually plucked off the yacht by a merchant vessel before the boat sinks (if it does at all in the end).

In regions with higher vessel numbers, obviously will be more cases but I doubt that the actual chance of use in most places is as much as it is here due to the very few refuges about our coast and the long ocean passage required to get anywhere else.

Before the assumption mongers jump in /forums/images/graemlins/frown.gif, I am not suggesting they not be carried, we carry both (although I would pass at routinely carrying a defibrillator).

John

 

[Rob_Webb]

I've been on plenty of cruising boats where they've carried de-fibs - usually on the basis that having spent $1,000s on other safety equipment why not maximise your chances and spend a bit extra on this scenario? Brought it home to me when I arrived in Vanuatu a couple of years back and yacht came in next day with one dead crew member (50-ish Aus guy) who pegged out a few days earlier - no de-fib onboard.

Sobering experience to have to use tho so be prepared.

And of course we carry em on CG boats.

 

[Ships_Cat]

Hi Rob

I would feel quite confident that it would be the case that around here more yacht peeps would have heart attacks on board (and even die) in one year than the total number that have ever had to get into liferafts.

What would be your call on that?

{Whoops interrupted this to say hi to the local big police launch which does alot of rescues around here paying a check through the marina and did a 180 off our stern - they can just fit lengthways across the aisle with a couple of feet to spare so always nice to see them spin it around not missing a beat}

Regards

John

 

[Sniper]

two points:

1) a defibrillator may only help in the case of a VF/VT arrest. It is of no use in the case of a heart attack alone, which is the more likely scenario to be encountered.

2) If someone does arrest, defibrillation is the definitive treatment for VF/VT arrest BUT it is not a sure fire answer. Unless, as dralex says above, the arrest is due to one of the 8 reversible causes (4Hs, 4Ts) the underlying pathology is likely to indicate a very poor longer term prognosis. (one of the major gripes with programmes like 'casualty' is the impression given that every arrest can be immediately shocked back into a perfusing rhythm and the patient will be sitting up within 5 minutes receiving counselling about their lifestyle choices - the vast majority of arrests do not regain an output in a prehospital situation)

On the other hand, one of the 4 Hs is hypothermia, so one could argue that this increases the potential value of cruising boats carrying defibrillators. In any case, I suppose the defib only has to work once for it to be considered a worthwhile investment.



You pays yer money.....

 

[tazzle]

I'm not sure I understand the medical points, but in lay-speak it seems this particular de-fib won't attempt a shock if the heart is stopped as it needs to detect some heart activity to calculate the charge - would this be correct? So the 'casualty' scenario in which the dead are brought back to life by a de-fib is just TV myth?

 

[Sniper]

This defibrillator will be an AED (Automatic External Defibrillator) which is the sort that are quite commonly available in public places. The AED carries inside it some fairly sophisticated software which detects the electrical activity in the heart and determines whether or not the rhythm is shockable. This means that they are fail-safe - if you put the pads on a healthy person with normal sinus rhythm, for example, the machine would not allow a shock to be administered. Equally, a patient in asystole (so-called 'flat line') would not be shocked as this is a non-shockable rhythm - its a dead heart.

Defibrillation works by stopping all electrical activity in the heart momentarily in the hope that the natural in-built pacemakers in the heart will then kick back in with a regular, perfusing rhythm. It's a bit like giving someone having hysterics a good slap in the face - the intention is to bring them to their senses!

As far as the 'casualty' scenario goes, it's not quite a myth; someone in VF/VT arrest is effectively dead (they usually look it) so defibrillation may ostensibly bring them back to life. Where programmes like this are (IMHO) at fault is in giving the impression that defibrillation is almost always succesful - sadly this is not the case.

 

[jimi]

Every single handed sailor should carry one. It may be his one chance to resusitate himself!

 

[Anchorite]

Nah: you need two hands for these things /forums/images/graemlins/wink.gif

 

[DinghyMan]

I did the training and was an AED operator for St John Ambulance for a couple of years - the AED's that you see in shops and railway stations are fairly operator proof as they talk to you and tell you exactly what to do and when.

The AED course was the first first aid course I went on where they spent a lot of time explaining that there was a very good chance that you would loose the casualty and the survival rates were pretty low even with near instant treatment and then shipping off ASAP.

As you say the AED's treat VF/VT only and only the bigger more complex defib's treat anything more, and very few first aiders are trained to use them.

One other thing to consider was that I was required to requalify every 90 days to keep my qualification and the initial test and re-qual test were pretty keen.

 

[Peter2B]

Just a question - what if you have to use one on a MOB victim who goes into cardiac arrest just after you've got him out of the drink, or on som eone who's just soaked from sailing? Surely you can't use those defibs on a wet patient, or when standing on a wet surface? Kinda defeats the purpose, I would reckon....