Re: How would you do a sleep apnea detector?
John Woodgate
wrote (in <5CKTd.22491$755.6677@lakeread05>) about 'How would you do a
sleep apnea detector?', on Fri, 25 Feb 2005:
>I guess we would be looking for breathing interruptions. So, something
>around the chest? Looking for absence of change?
Do you want to detect it when the sleeper awakes abruptly, gasping for
air, or as soon as the breathing reflex is suppressed?
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
mike
news:pElfnyEe...@jmwa.demon.co.uk:
> I read in sci.electronics.design that George <gh424NO...@cox.net>
> wrote (in <5CKTd.22491$755.6677@lakeread05>) about 'How would you do a
> sleep apnea detector?', on Fri, 25 Feb 2005:
>
>>I guess we would be looking for breathing interruptions. So, something
>>around the chest? Looking for absence of change?
>
> Do you want to detect it when the sleeper awakes abruptly, gasping for
> air, or as soon as the breathing reflex is suppressed?
CPAP machines do it by monitoring the airpressure in the line, duration of
breath and duration of pause. Usually suffers do not wake, gasp for air or
whatever.
Ken Taylor
news:Xns9608931C5D7...@199.45.49.11...
I don't wake gasping for air but it's like an electric shock to the head
that wakes me up. Fortunately not doing it so often these days.
Ken
John Woodgate
<Xns9608931C5D7...@199.45.49.11>) about 'How would you do a
sleep apnea detector?', on Fri, 25 Feb 2005:
>CPAP machines do it by monitoring the airpressure in the line, duration
>of breath and duration of pause. Usually suffers do not wake, gasp for
>air or whatever.
I didn't know that. My father did. Loudly.
Spehro Pefhany
<j...@jmwa.demon.contraspam.yuk> wrote:
>I read in sci.electronics.design that mike <mi...@nospam.com> wrote (in
><Xns9608931C5D7...@199.45.49.11>) about 'How would you do a
>sleep apnea detector?', on Fri, 25 Feb 2005:
>
>>CPAP machines do it by monitoring the airpressure in the line, duration
>>of breath and duration of pause. Usually suffers do not wake, gasp for
>>air or whatever.
>
> I didn't know that. My father did. Loudly.
So did mine. You wouldn't have needed much in the way of audio
processing to pick it up.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Active8
Losing weight might help. An ENT doc will gladly cut on you, but
excess weight messes with the throat and nasal passage.
--
Best Regards,
Mike
boB
I have had sleep apnea for many years and use a CPAP machine. Yes,
sufferers DO gasp for air. They may not wake up enough to know they
are doing it though. Thats' why it needs to be detected. Usually in
a sleep lab like I went to. They hook all sorts of stuff up to you,
but one thing they use is, as one mentioned here, a band around the
chest. As I understand it, it changes resistance when stretched, like
happens when you inhale. We also had a small one of those bands many
years ago when I worked a medical electronics company to detect
breathing problems in sleeping babies trying to find to SIDS related
problems.
They also monitor EEG and blood O2 in the sleep lab.
One problem with sleep apnea is that it raises your blood pressure and
also you don't get a good night's sleep among other things that I
don't remember.
The CPAP machine just forces air down your throat so it doesn't stick
shut. Has worked great for me.
boB
Ken Taylor
news:myzx0qooidki$.dlg@ID-222894.news.individual.net...
Oddly enough, I'm better now than when I was 15kg lighter and running
half-marathons. But I know what you mean.
Cheers.
Ken
JeffM
>Maybe some kind of slide pot or strain gauge
> George
Used on infants, astronauts, and in sleep labs:
http://images.google.com/images?q=inductance-plethysmograph
http://www.google.com/search?&q=CHIME-monitor+Apnea+Inductance-plethysmography
Guy Macon
mike wrote:
>CPAP machines do it by monitoring the airpressure in the line,
>duration of breath and duration of pause. Usually suffers do
>not wake, gasp for air or whatever.
Please refrain from posting on subjects that you know nothing about,
especially in the area of medicine where your false information
could hurt someone.
Let's start with a minor error before going on to the glaring ones;
You really shouldn't be talking about "sleep apnea." when you really
mean "obstructive sleep apnea" (OSA). Central sleep apnea (CSA) has
another cause, and a CPAP machine will do *nothing* to help. (For
the electronics discussion, any apnea sensor would suffice - no need
to differentiate between central/obstructive.)
Now for the more glaring errors; CPAP machines have *no monitoring
at all*. CPAP stands for [C]ontinuous [P]ositive [A]irway [P]ressure,
and that's all it does - pressurizes the airway to prevent collapse.
For the majority of OSA sufferers, that's enough.
BiPAP ([B]ilevel [P]ositive [A]irway [P]ressure) (AKA VPAP and
Bilevel - BiPAP is a trademark) machines do have a sensor, but it
does *not* sense apnea. With BiPAP the pressure changes during
each breath cycle. Inhale = typical CPAP pressure. Exhale = lower
pressure.
STBiPAP is [S]pontaneous [T]imed [B]ilevel [P]ositive [A]irway
[P]ressure. If the patient stops breathing the STBiPAP machine
will breath for them - in essence it is a part-time respirator.
This is the minimum system top treat central sleep apnea.
Your "Usually suffers do not wake, gasp for air or whatever"
statement is also false. OSA sufferers uUsually show these
symptoms. One has to be aware that sometimes they don't, but
that's not nearly as common.
Please don't post about medical issues ever again. One of these
days you are going to kill someone.
--
Guy Macon <http://www.guymacon.com/>
Yukio YANO
> I guess we would be looking for breathing interruptions. So,
> something around the chest? Looking for absence of change?
>
> least as a screening device.
>
build a Pulse Oximeter ! (do a Google search)
one Photo-transistor, one 650 red Led and one 900 IR led
and all the Logic to read and translate the results
Or buy a Finger Pulse Oximeter . Buy-Now on E-Bay ~$250, say you want it
for Mountain Climbing ! If you hold your breath, blood oxygen levels
will quickly begin to drop, So there is no need to monitor breathing, it
really is blood oxygen levels that are important !, breathing is only an
indirect indication of oxygenation levels, especially at higher
altitudes. Buy at $250, use for week, sell for $200, can't get a sleep
study for $50.00
Yukio
Jim
measuring the oxygen in the blood. It shined a red LED through the end of
my finger and an optical detector on the other side was able to measure how
red the blood in my finger was.
The assumption being that Apnea would cut off breathing enough to make a
measurable difference. It worked rather nicely.
It was a professional system, complete with a recording device to store
the measurements.
So, while a sleep study at a sleep center gives much more meaningful data,
this was a "Take Home" device for a preliminary check for Sleep Apnea. I
suppose somebody could make their own, since it is not invasive, or pose any
risk to the user.
Jim Pennell
Luhan Monat
Hi,
Interesting point. However, this is not a medical venue. No one should
expect expertise in medicine here, only, hopefully, good advice on
engineering and such.
As far as the legality goes, anyone *but* a doctor can freely give
medical advice without liability as long as they don't represent
themselves as a licenced medical pratictioner.
The same goes for any professional field, doctors can give legal advice,
florists can give realestate appraisals, etc, etc.
If my understanding here is not correct, I'm sure someone will let me
know. (Of course, if they are not a lawyer, I'm not sure if that counts
either).
--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm
Guy Macon
Luhan Monat wrote:
>Interesting point. However, this is not a medical venue. No one should
>expect expertise in medicine here, only, hopefully, good advice on
>engineering and such.
>
>As far as the legality goes, anyone *but* a doctor can freely give
>medical advice without liability as long as they don't represent
>themselves as a licenced medical pratictioner.
>
>The same goes for any professional field, doctors can give legal advice,
>florists can give realestate appraisals, etc, etc.
>
>If my understanding here is not correct, I'm sure someone will let me
>know. (Of course, if they are not a lawyer, I'm not sure if that counts
>either).
This isn't about doing what is legal, but rather about doing what
is right. Yes, a non-doctor can legally give medical advice that
might kill someone. It would still be wrong to do so. We have a
moral and ethical obligation to do what is right, even when doing
what is wrong is perfectly legal.
...so next you put the uranium hexafluoride into the centrifuge...
Luhan Monat
Again, intersting point; I do not disagree. Yet, 'what is right' is
also sometimes indeterminate. The lesson here is more like 'cavaet
emptor' - anyone would be well advised to not take undo risks based on
*any* advice found in a newsgroup, period.
mike
@corp.supernews.com:
Another post said quite rightly that this isn't a medical forum. My
Apologies. This will be my last comments on the subject;
Over reaction? touch a nerve somewhere? and you made a few false
assumptions;
CPAP machines do *monitor the air pressure*, more later.
I unfortunately do know something on the subject, did not suggest a CPAP
would cure SA, OSA or CSA, and you're entirely right CPAP doesn't help
CSA as I know from first hand, - but I didn't see anything about that in
my post however and nothing mentioned would reasonably constitute
dangerous medical advice.
To be clear SA is dangerous because the majority of suffers *don't wake
or gasp for air*. They are not the first or primary symptom and that's
why it's potentially dangerous, and can be so before anyone gets to the
waking and gasping stage. *Hence my comment*
FYI the polysomnogram results are only reliable for diagnosis when the
subject is *asleep*. Most with SA do not knowingly wake up as a result.
All this from the ASAA and several clinical physicians and easily
accessable on the web.
If it suits you better then I suggest the OP gets a Sleep study, OK?
And lets agree to say that *some* CPAP do monitor and record apnea - by
measuring pressure - and so my original suggestion has some merit.
Most of the machines today have data storage. Each of my machines over
the last six years has done so - it's not directly available to the user
but recorded on memory card for access by phone or by taking the card to
a suitable clinic reader. The clinic then can analyze the results -that's
usually the machines are calibrated and treatment managed over extended
use periods - this record includes apnea event logging. Mines an SD card
format and it's readable on a PC with some formatting.
As to my knowledge? I've had Mixed apnea (OSA and CSA) for six years and
my wife is a tech nurse at the local sleep clinic.
Phew - all that from a two liner.
John Woodgate
<2KQTd.4510$1S4.5...@news.xtra.co.nz>) about 'How would you do a sleep
apnea detector?', on Sat, 26 Feb 2005:
>Oddly enough, I'm better now than when I was 15kg lighter and running
>half-marathons.
You may have been chronically dehydrated, which can give symptoms very
like sleep apnoea.
Ken Taylor
news:Uw4Q6lBW...@jmwa.demon.co.uk...
> I read in sci.electronics.design that Ken Taylor <k...@home.nz> wrote (in
> <2KQTd.4510$1S4.5...@news.xtra.co.nz>) about 'How would you do a sleep
> apnea detector?', on Sat, 26 Feb 2005:
> >Oddly enough, I'm better now than when I was 15kg lighter and running
> >half-marathons.
>
> You may have been chronically dehydrated, which can give symptoms very
> like sleep apnoea.
> --
> Regards, John Woodgate, OOO - Own Opinions Only.
Hmmm, interesting. More food for thought (although I don't want to put on
any more weight...)
Cheers.
Ken
Greg Neff
wrote:
>I guess we would be looking for breathing interruptions. So,
>something around the chest? Looking for absence of change?
>
>Seems like something short of a hospital sleep study is needed, at
>least as a screening device.
First, I have to say that a sleep study is necessary if sleep apnea is
suspected. I would not recommend any other course of action.
I have had several sleep studies over the last ten years. I have OSA
and am using CPAP.
I am not a doctor or a sleep tech. The following is observation and
conjecture on my part:
With respect to OSA, the sleep apnea events don't seem to concern the
doctors too much, they seem to be more worried about the resulting
effects (low oxygen and inadequate sleep). Even though I had
significant OSA for a number of years, they didn't recommend treatment
until a study showed oxygen saturation levels dipping below 80%.
The oximeter suggested by others would be a very important indication
that something is wrong, but would not directly detect sleep apnea
events. You can't conclude that low oxygen saturation is caused by
sleep apnea.
The chest strap night be a better indication of a long pause between
breaths, indicating a sleep apnea event. They also put a sensor under
your nose, which appears to be a thermocouple. I suspect they use
this to detect exhaled (warmer) air. The chest strap probably detects
all breathing events, and the thermocouple might be used to discern
mouth breathing.
None of my sleep studies used any equipment to measure pressure.
You may also want to check out alt.support.sleep-disorder.
================================
Greg Neff
VP Engineering
*Microsym* Computers Inc.
gr...@guesswhichwordgoeshere.com
Glen Walpert
There was an op-ed column touching on the subject of dehydration in
the July/Aug Medical Design News magazine, not on their web site so
ripped off in its entirety below, in the interest of public health:
Thirsty? Want Water or Coke?
Read the facts and then decide.
Water
1. 75% of Americans are chronically dehydrated. (This likely applies
to half the world population.)
2. In 37% of Americans, the thirst mechanism is so weak that it is
often mistaken for hunger.
3. Even mild dehydration will slow down one's metabolism as much as
3%.
4. One glass of water shut down midnight hunger pangs for almost 100%
of dieters participating in a U-Washington study.
5. Lack of water is the #1 trigger of daytime fatigue.
6. Preliminary research indicates that 8 to 10 glasses of water a day
could significantly ease back and joint pain for up to 80% of
sufferers.
7. A mere 2% drop in body water can trigger fuzzy short-term memory,
trouble with basic math, and difficulty focusing on a computer screen
or on printed pages.
8. Drinking five glasses of water daily can decrease the risk of
colon cancer by 45% and slash the risk of breast cancer by 79%. These
drinkers are also 50% less likely to develop bladder cancer.
Coke
1. The active ingredient in Coke is phosphoric acid with a pH of 2.8.
Phosphoric acid also leaches calcium from bones and is a major
contributor to the rising increase in osteoporosis.
2. To clean a toilet: Pour a can of Coca-Cola into the toilet bowl
and let the "real thing" sit for 1 hr, then flush clean. Citric acid
in the soft drink removes stains from vitreous china.
3. To remove rust spots from chrome car bumpers: Rub the bumper with
a rumpled-up piece of aluminum foil dipped in Coca-Cola.
4. To clean corrosion from car-battery terminals:
Pour a can of Coca-Cola over the terminals to bubble away the
corrosion.
5. To bake a moist ham: Empty a can of Coca-Cola into the baking pan,
wrap the ham in aluminum foil, and bake. Thirty minutes before the ham
is finished, remove the foil, allowing the drippings to mix with the
Coke for a sumptuous brown gravy.
6. To remove grease from clothes: Empty a can of coke into a load of
greasy clothes, add detergent, and run through a regular cycle. The
Coca-Cola will help loosen grease stains. It will also clean road haze
from a car's windshield.
Abstracted from various Internet sites.
www.medicaldesignnews.com
Wim Ton
"George" <gh424NO...@cox.net> wrote in message
news:5CKTd.22491$755.6677@lakeread05...
> I guess we would be looking for breathing interruptions. So,
> something around the chest? Looking for absence of change?
>
> Seems like something short of a hospital sleep study is needed, at
> least as a screening device.
Long ago "Electronic design" described a system where the movement of a
laboratory rat was monitored by placing 2 capacitor plates at the and bottom
of its cage. It claimed that it was sensitive enough to detect breathing.
Maybe it can be scaled up to humans. It is contactless and non-intrusive. Of
course it needs filtering to separate the breating form other movements
Wim
Rich Grise
Does this device use that same finger clip that they use when they're
taking your vitals at the clinic? Wouldn't that fall off as you toss
and turn in your sleep? Do they make one for, say, an earlobe?
Thanks,
Rich
Luhan Monat
> I guess we would be looking for breathing interruptions. So,
> something around the chest? Looking for absence of change?
>
> Seems like something short of a hospital sleep study is needed, at
> least as a screening device.
>
I would go with the chest strap used in polygraphs. From there, store
data in large eeprom using a pic. Dump data to computer the next day.
boB
>CPAP machines do *monitor the air pressure*, more later.
Mine doesn't, unless, maybe, it does internally for regulation
purposes. It's a Sullivan machine.
boB
Guy Macon
boB wrote:
>
>>CPAP machines do *monitor the air pressure*, more later.
>
>Mine doesn't, unless, maybe, it does internally for regulation
>purposes. It's a Sullivan machine.
You are correct in that most CPAP machines monitor pressure at
a point close to output that feeds the tube going to the mask.
That pressure sensor always see a constant pressure (that's why
it is there, as part of the pressure regulator). and thus is
useless as a detector of apnea. Note that "sensor" doesn't always
mean "electronic"; it might very well be a mechanical pressure
regulator valve.
Some machines do make a recirding of sorts, but they typically
monitor time spent with the mask on and time spent with it off
while the machine is running, and total running hours. This
helps to identify patients whomtrow off the mask during the
night. Needless top say, a CPAP manufacrurer can put all sorts
of extra monitoring and recording features in, but that the
ordinary run-of-the-mill CPAP machine is simple a source of
constant pressure. Add-on sensors and recorders are no more
a universal part of the basic machine than humidifioers are.
Getting back to the topic at hand, a low-cost home apne detector
would be a Very Good Thing. It would result in many more people
getting a proper sleep study after finf=ding out there was a
problem. It would have to be designed to minimize false negatives;
you don't want the low-cost apnea detector to tell you that you
areOK when you are not. Flase positives are less important unless
thay are so common that people percieve the unit as crying wolf.
boB
<_see.web.page_@_www.guymacon.com_> wrote:
>Getting back to the topic at hand, a low-cost home apne detector
>would be a Very Good Thing.
It might at least get the person to go to a sleep lab and have them
properly diagnosed. they're not going to just sell you a machine I
don't think.
boB
JeffM
> Guy Macon
This is not quite the same thing (you gotta go in to get rigged),
but ambulatory systems have been around for 25 years.
Inductance plethysmograph (~400kHz) determines the cross-sectional area
of your abdomen and thorax.
Deltas are derived with a PLL.
Back then, it was recorded with a Walkman-like recorder,
PWMed and FMed to get 8hr on a C-120.