How would you do a sleep apnea detector?

Well, I don't really want to treat it, just see if it's happening. So I think I would want to detect when breathing stops.

Maybe some kind of slide pot or strain gauge, an ADC, and some clever programming on my old C64? :-)

So did mine. You wouldn't have needed much in the way of audio processing to pick it up.

Best regards, Spehro Pefhany

Used on infants, astronauts, and in sleep labs:

Losing weight might help. An ENT doc will gladly cut on you, but excess weight messes with the throat and nasal passage.

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

I read in sci.electronics.design that George wrote (in ) about 'How would you do a sleep apnea detector?', on Fri, 25 Feb 2005:

Do you want to detect it when the sleeper awakes abruptly, gasping for air, or as soon as the breathing reflex is suppressed?

John Woodgate wrote in news: snipped-for-privacy@jmwa.demon.co.uk:

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 read in sci.electronics.design that mike wrote (in ) about 'How would you do a sleep apnea detector?', on Fri, 25 Feb 2005:

I didn't know that. My father did. Loudly.

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).

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

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.

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

A sleep apnea monitor that was used on me a long time ago was based on 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

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...

Guy Macon wrote in news:111vmtostpenuc0 @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.

I read in sci.electronics.design that Ken Taylor wrote (in ) about 'How would you do a sleep apnea detector?', on Sat, 26 Feb 2005:

You may have been chronically dehydrated, which can give symptoms very like sleep apnoea.

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

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

Hi,

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.