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Re: Defibrillator

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi Jonathan, Jim, all,

I am also a firefighter by profession, though I do NOT carry an
EMT license (that's because I entered the fire service in 1988
and my municipal employer didn't require EMT certification for
firefighters until 1991). I do come across defibs quite often in the
course of my job however and as a matter of fact, we carry an
automatic defib on the fire apparatus that I drive. We were just issued
it a few weeks ago and haven't had to use it in the field YET. Most
of the defib caps that I have come across look to be in the 5.2 kV
at 34 uFd range but are surprisingly small for that much
energy (high energy density). The "standard" shock settings are
200 and 360 joules, so using the energy formula E= 1/2CV~2,
that means a 34 uFd cap would need to be charged to3430 volts and 4600 volts
to deliver a 200 J and a 360 J shock, respectively. Of course, these are the shock energy settings for the older defibs carried on ambulance units and I'm not really 
sure what the settings for the fully automatic ones that are desinged
for use by any reasonbly prudent adult of the general public as there
are no external controls for the shock delivery (that's probably a good thing!)
The thought of John Q Public being able to shock the first person he/she see's fall 
unconscious is a bit troubling to me as an emergency service professional but I
understand that these newer auto befibs are pretty much "idiot-proof".

David Rieben



----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, May 09, 2006 2:34 PM
Subject: RE: Defibrillator



Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hi Johnathan,

Yes the burns from a pig one may not want to survive, yet the line is
carrying far more current, not that it would matter much.

Staying on topic, I was thinking more about 240 or 440 accidents which occur
more frequently.

It would be nice to have one in every household, especially past fifty! Say
how big of cap/V is in those? Any know?

Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, May 09, 2006 10:11 AM
To: tesla@xxxxxxxxxx
Subject: RE: Defibrillator

Original poster: "Jonathan Peakall" <jpeakall@xxxxxxxxxxxx>

The price of AED's is dropping. However, the comments below are correct in
that asystole (flat line, heart stopped) is more likely to occur than v-fib
from electrical shock. After all, the way an AED works is to STOP a heart
that is in v-fib, and then (hopefully) the heart restarts itself with a
normal beat.

I once was at a scene (I'm a firefighter/EMT) where a cable guy got hit with
12kV from a power line. He was driving a cherry picker extended, and came in
contact with the power line. He was horribly burned, lost a leg and his
genitals were a charred lump. His heart however, was still beating. I heard
that the poor guy lived.

  >I
 >read somewhere a while ago when defibs were becoming available to the
 >public that defibs are less effective than CPR.

The above is untrue. If a person having a heart attack is hit with an AED
within 10 minutes, their chance of survival is very good. After ten minutes
the chance drops dramatically. AED's are going to be in every public place
very soon. They key to an AED being effective is rapid use.

If you really want one, contact me off list, I have a friend who sells them
for a living and maybe he would give you a deal.


Jonathan
www.madlabs.info



 > Original poster: "Peter Terren" <pterren@xxxxxxxxxxxx>
 >
 > Possibly, but an automated defib unit will set you back what most
 > people spend on their hobby in a couple of years. It still requires
 > someone else to use it.
 > I am not sure if we really know how much electrocution is due to
 > persisting VF after removal of the HV source rather than asystole,
 > major burns or prolonged respiratory arrest due to sustained
 > application.  Asystole (electrical standstill) will generally recover
 > itself once the current is removed and this will usually occur with
 > DC greater than 200mA across the chest whereas VF occurs between
 > 100mA to 200mA very roughly and tends not to recover spontaneously
 > unless it is clamped down into asystole with a further DC/Bipolar shock.
 > I have several functioning non-automated unipolar defibs but don't
 > bother keeping one on. Perhaps I should...
 > Peter  http://tesladownunder.com
 >
 >
 > >Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
 > >I am wonder if a defib would be a worthwhile safety addition in our
 > >trade. Fire extinguishers and at times HV gloves and bang sticks are
 > >worth while. I don't recall anyone mentioning a defibrillator on hand.
 > >.... Regards,
 > >Jim Mora
 >
 >
 >
 >
 >