X-Message-Number: 5581
Date: Sat, 13 Jan 1996 23:11:11 -0500 (EST)
From: Charles Platt <>
Subject: emergency alerts (fwd)

The following exchange occurred on a different mailing list but is 
relevant to all cryonicists and is therefore being crossposted to CryoNet.

--CP

---------- Forwarded message ----------
Date: Sat, 13 Jan 1996 12:14:16 -0500 (EST)
From: Charles Platt <>
To: CryoCare Forum <>
Cc: Charles Platt <>
Subject: emergency alerts

On Sat, 13 Jan 1996, Mike Darwin wrote:


> GOOD LUCK!!!!!  You think motion sensors have problems!  Wow!  try using a 
radio
> transmitter.  Do you have a cordless phone?  Had any problems as you moved
> around?  Considered the power supply problem?  A transmitter takes a lot of

> juice.  To be sure it is working properly it would have to send out test 
signals

> periodically.  This means power, this means batteries.  Transmitters are not 
to
> be confused with wrist-watch sized recievers like pager watches.  They are
> bigger and they need bigger batteries.

Now, Mike, we each have our special areas of knowledge, and frankly, 
yours is not hardware. There are possible answers to all your rather 
scathing quibbles.

For example:

The pulse monitor would require a very small amount of power to detect
heartbeats. The base station (there might need to be more than one in a
large home) can send an interrogatory message to the monitor every minute
or two. If the monitor is detecting a pulse, it responds with a very brief
(milliseconds) return signal requiring very little power. If the monitor
is NOT detecting a pulse, it responds with a different signal. If the base
station is unable to make contact with the monitor, it tries repeatedly;
if still no success, it sounds an audible alarm in the home where it is
installed, to alert the user that the system isn't working. If the user 
doesn't respond, the base station dials for medical help.


> Ever owned a pulse detecting watch?  Ever seen it give false readings or fail 
to

> read?  These things are pretty reliable, but not reliable enough without a lot
> of fine tuning.

In the system I have outlined, the detector could send a third type of
signal if it is currently unable to get a good reading from the patient.
The base station could then sound a different kind of alarm, telling the
user than the monitor has been misaligned or whatever. Bear in mind that
we're not interested in how fast the pulse is beating, only whether it is
beating at all. Surely it would be trivial to design a system to detect
this with reasonable reliability.

> All do-able.  But not straightforward.  I've seen several

> people try to tackle this problem of transmitters and these were the problems:
> 

> 1) Compliance: if it is bulky and not actively useful like a pager or cell 
phone

> people will not wear it.  If it requires electrodes or patches to be attached 
to
> skin compliance goes to near zero in "healthy" (i.e., not dying) people.
> Compliance was lousy in dying people too.

I agree the device has to be unobtrusive, but I don't see why electrodes or 
patches would be necessary. See below.

> 2) The proliferation of cordless phones, radio operated devices, pager

> transmissions, computers and other sources of noise is a major problem to use 
of
> a transmitter.

Depends which frequently band you use. Regular cordless phones suck, but
the high-frequency models (which cost twice as much) are better. In any
case, in my outlined system the base station would make repeated attempts
to establish contact with the monitor device before giving up and sounding
an "out of touch" alarm. This would allow the user to move through brief
"dead spots" in the transmitter coverage without being annoyed by alarm
signals. 

> 3) Hospitals use a device called a radio Holter monitor which transmits EKG
> continuously to a recorder and the nurses' station.  It is necessary to put

> antennae at 10 ft. intervals in the halls.  You will have to have an antennae 
in
> every room of the home.  If you go outside, it will alarm. Big nuisance=lousy
> compliance.

You're describing a system which requires high bandwidth: a large
continuous stream of data. Mine would require only a very brief
interrogatory message every minute or so. 


> 4) The point of the system I describe is that it requires nothing more than 
use
> of a conventional alarm system.  When you come home you switch on, when you

> leave, you switch off.  A simple light switch like on-off device would work as
> well as a keypad.  It's simple and easy.

The on/off problem is trivial; any system could have sensors at each door 
which would automatically register when the user arrives or leaves.

> 5) Any transmitter will be likely be removed for showering, bathing and some
> autoerotic activities. It will also be removed by some people who defecate

> before showering. These are very high risk times; falling in the tub is a 
common
> way to die. Passing stool is also a high risk activity (see below).  When you

> take the transmitter off you must disable the system and re-enable it when you
> put it on.  VERY inconvenient.  Compliance will be very poor.

This is a more interesting problem. I suggest that when you take off the
sensor, the act of doing so puts it in a standby mode. Half an hour later,
if the sensor hasn't been donned again, it tells the base station to sound
an audible alarm, reminding the user. If the user doesn't respond, the
base station sends its medical alert. 


> 6) An AVID chip implanted in the nape of the neck or a card or necklace with a
> passive transmitter could make turning the switch off and on when leaving the
> home unnecessary. 

Excellent idea. More to the point, the chip could contain the pulse sensor. 


> Where ever did you get the notion that SCD victims have time to push a button?
> No way.  Most SCD victims just fall over dead. 

Here your experience is obviously greater than mine. The one time I saw 
someone have a heart attack, she had a lot of time to talk about it. I 
didn't realize this is not the norm.

-------------------

I suggest I copy this discussion to CryoNet. There are people reading 
CryoNet who actually design hardware (well, I should say at least one 
person--Keith Lofstrom, an integrated circuit designer).

Okay with you if I repost your msg and mine?


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