Measuring Untreated AHI

My Question

I've seen some users on this board refer to "doing your own sleep study" with a full data machine. I've got a full data APAP, and I'd like to measure my untreated AHI. I know how to use the machine, import the data, use the SleepyHead software etc. My questions are:

How should I set the machine to get the best estimate of my untreated AHI?
How close of a measure can that give me on my untreated AHI?

I'm guessing I should set it to a low pressure so that it doesn't interfere with any hypopnea events. Right now it's set to 4cm. But I wasn't sure if there was maybe a reason I should set it higher, like, maybe if it's too low the machine has a hard time detecting hypopneas.

I've looked on the wiki, did some googling, couldn't find an answer. Thank you for enlightening me!

Background (feel free to skip )

I'm asking for help here after a poor experience with a sleep therapist.

My girlfriend has been telling me that I stop breathing while I'm asleep, gasp for air, she gets concerned, etc. I do get pretty tired at work, though I'm not sure if that's because of quality of sleep or quantity. And I do have snoring issues, and sometimes I'll wake up gasping if my sleep is particularly agitated.

So I visited a sleep therapist and got signed up for an at-home test from Apria. Their therapist showed me how to the use equipment and let me know I'd have to get at least four hours of sleep on the machine or they'd order a re-do. When I got it home, sleep was tough with all that gear on. I laid down for two hours; felt like I got 15 minutes of sleep but it might have been the whole two hours. I got up and read for three hours, hoping I'd get tired, but finally I took the machine off when I realized it wasn't going to happen.

When my therapist called with the results, she said I had slept five hours and had ~five hypopneas. I tried telling her a couple of times that I slept at most two hours, maybe only fifteen minutes. "Oh, we get people into the lab and it's pretty common that they vastly underestimate how much they slept." After being shut down a couple of times I didn't feel like explaining that I was out of bed, sitting up, reading for three of those five hours.

And I thought I could diagnose myself for less than another visit to Apria. I got a recording oximeter, slept with it, and it showed dips, but nothing below 92%. Then I read that apnea might or might not show up as measurable hypoxia. So now I've got my hands on a used full-data machine and I've got those questions above.

Hope I can learn enough from you all here to dispense a little knowledge when it's my turn. Thanks!

Hello and welcome. Sorry to hear about the person who blew you off about how long you slept. Do you have a copy of your detailed sleep report? All that information is there. It's always a good idea to have a copy for your own records. Maybe you can still get it. I don't think there is any way to determine your untreated apnea with a machine. Even at 4 there is some treatment, albeit not much. I personally would not want to subject myself to a pressure of 4 for the night, but hey, that's up to you. When doctors order home studies for diagnosis they use sensors, not these machines. The machine can be used for titration. If you start with a range of 4 to 20 you'll begin to see a pattern of the pressure you usually need. Most people then increase the lower end up as needed to ward off most events. A count would be nice to know, especially if one is deciding whether to pursue another study to get insurance coverage, but it may require getting a home study where you'll likely sleep better. Let us know what you decide to do. If getting insurance to cover supplies isn't a factor, optimizing treatment with this machine is a viable option.

KGZotU wrote:My girlfriend has been telling me that I stop breathing while I'm asleep, gasp for air, she gets concerned, etc. I do get pretty tired at work, though I'm not sure if that's because of quality of sleep or quantity. And I do have snoring issues, and sometimes I'll wake up gasping

Given those symptoms, it seems fairly certain you have sleep apnea.

KGZotU wrote:How should I set the machine to get the best estimate of my untreated AHI?

Set the pressure on straight CPAP of 4 cm. If you see a lot of events in the data, you can be fairly certain that this is a rough approximation of your untreated AHI. If you see no events, the issue is cloudy because it is possible that 4 cm pressure effectively prevented your events. But, the average required treatment pressure is around 10 and not many people are treated effectively at 4.

How close of a measure can that give me on my untreated AHI?

No one can know because you are getting 'some' treatment at 4 cm.

If it were me, I would follow kteague's advice - set the pressure range to 4 - 20 cm and then post Sleepyhead charts for forum members to comment on. (See https://sleep.tnet.com/resources/sleepyhead and particularly https://sleep.tnet.com/resources/sleepyhead/shorganize)

BTW, no insurance company will accept charts from your CPAP data as proof of diagnosis.

This is what I would do if I were in your shoes.
I would try the 4 to whatever range of pressures...if the machine consistently increases the pressure from 4 cm to whatever then I would know that the machine is responding to something. I might not know what it is responding to but the machines won't increase pressure without their feeling like something isn't right.

If I consistently saw the machine go to pressure so and so...depending on where it was going and how I felt I might tweak the pressure settings to optimize things.

We have no way to know what the machine might have prevented in terms of apnea events from the data available on the machines. We just don't have anyway to know but for me it wouldn't be so important to know what it prevented as to know it was preventing something.

Now if that 4 cm pressure line never moves off of 4 cm (assuming a person can comfortably use 4 cm) then we have a different discussion. 4 cm does offer therapy value and might be enough for some people (it's rare but not impossible).

Be aware that many people have trouble breathing at 4...If you are one of them...you may need the higher pressure provided by a CPAP.