Do I need a baseline?

[Mike44]

First time caller, longtime listener.

Hi everyone. This is a great forum, I have learned a lot.

First night with a Cpap device last night (DreamStation Auto). Tolerated it better than I expected and the reported AHI was better than expected (SleepyHead). Without getting into the details of that, it does bring up an area I'm confused about. It's not clear to me how to separate out the reporting function of my device vs. the therapy function. Acknowledging that one day of data doesn't mean a lot, the question becomes: Is the reported low'ish AHI an early indication that my apnea is not too bad, or is it an indication that the Cpap device was working great in it's therapy function during that first night, masked my true numbers and, without it, my AHI would be much higher?

I.E., don't I need a baseline to separate this out? Perhaps do a run with minimal pressures that will probably not help, so I can see what worst case is? Surprised that this hasn't come up before - probably proves I'm missing something...

-- Mike

[SleepDisturbed]

I'm not sure I understand your post completely, but I will do my best here --

My point of view is that a CPAP machine is not a diagnostic tool, it is a therapy device. The data recording functions are to try and track the effectiveness of the therapy.

It sounds like you have not had a sleep study. If that is the case, I would recommend that you get one as that will provide the 'baseline study' that you are asking for. That will tell you a lot of things, like the severity of your condition and what type of apnea you have -- different types for example need different types of machines.

Good luck!

[lawr1000]

PAP machines are not designed to monitor they provide therapy. So even with low pressures you are getting some form of therapy. Most consider a sleep study as their baseline.

[Julie]

If you monitor with SH for a certain time, e.g. weeks, you'll get a baseline consensus of some kind, to what end I'm not sure though. However it can help you to set your low pressure if you don't have a scripted setting (and so often they're 'just' the default low of 4 anyhow, as doctors think autos are magic and can address any event, no matter how high, in time to stop it (or stop follow ups) from 4, which is not the case of course. But if you see that you rarely go below e.g. 7 or 8, then you could set your low pressure at 7 and the high one at e.g. 15 (or leave it at 20).

[Pugsy]

Is the reported low'ish AHI an early indication that my apnea is not too bad, or is it an indication that the Cpap device was working great in it's therapy function during that first night, masked my true numbers and, without it, my AHI would be much higher?

Without the machine your AHI would be higher. It's only reporting the events that it couldn't prevent. It's not reporting everything that might have happened..only stuff that it could stop or prevent from happening.

My AHI is around 50ish without cpap. With cpap it's usually under 1.0.

Not sure what you mean "do I need a baseline" ....are you saying you don't have a sleep study result to use as your baseline?
Are you self diagnosing and self treating? What was last night's AHI?
Do you know about the software so you can see the breakdown of that AHI?
If not, you can read about it here. https://sleep.tnet.com/equipment

[palerider]

I.E., don't I need a baseline to separate this out? Perhaps do a run with minimal pressures that will probably not help, so I can see what worst case is? Surprised that this hasn't come up before - probably proves I'm missing something...

no, you don't, not unless you're OC about numbers or something. all that really matters is good results.

and it has come up before, you can use google or other search engines to search the forum, just put "site:cpaptalk.com" in the query, along with whatever you're trying to find.

[ChicagoGranny]

First night with a Cpap device last night (DreamStation Auto). Tolerated it better than I expected and the reported AHI was better than expected (SleepyHead).

- What did your leak line look like?
- How do you feel today compared to when you weren't using CPAP?
- What are your pressure setting?
- How were your settings determined?
- What are your pressure relief settings, if any?

[Mike44]

Thank you all. As I expected there are lots of knowledgeable folks here willing to take time the time to help - what a great resource.

The subject line is misleading - I should have come up with something else.

I'm sure I'll have more questions over time but it is true that I don't really "need" a baseline. As a nerdy engineer I am very impressed with the technology (and complexity) of modern Cpap devices, but there's also a philosophical aspect which interests me and which I thought might appeal to this group as well (or perhaps not).

It does seem to me that, inherent in all Cpap devices, there is, first, a "detection" function. That is, through very elaborate statistical interpretations of solely basic respiratory data over time, the devices are able to make good guesses at a wide variety of apnea and apnea-related phenomena and their severity.

Once this is determined, there is, it seems to me, a "therapy" function in which, given the identified instances the automation has identified above, very sophisticated algorithms are applied (often modified and improved by long term trends) to apply the proper amount of pressure predicted sufficient to keep the airway open but not so much as to unduly disturb sleep. As an aside, to the extent that long-term trends are recognized, some of "today's" therapy addresses "yesterday's" problem - which is OK - averages are useful and important.

These are 2 incredibly complex jobs but, it seems to me they are, almost by definition, independent. I see no reason why the existing "detection" function can't be easily separated from the "therapy" function (by simply nulling all therapy activity) to increase available diagnostic info. Well, I guess I can - the medical establishment, for reasons good and bad, probably doesn't want to release its stranglehold on such easily obtained diagnostic info (which I admit could be misused) as long as the alternative is a $5,000 sleep study.

All of this is just navel gazing, I suppose. The important thing, as has been pointed out, is the benefits.

-- Mike

[Julie]

Keep one thing in mind when trying to separate the two functions... whatever your therapy 'result' can differ from night to night for lots of reasons, even if only a bit, so again, trying to get exact #'s to make comparisons is quite iffy - we're not machines .

[ChicagoGranny]

I see no reason why the existing "detection" function can't be easily separated from the "therapy" function (by simply nulling all therapy activity) to increase available diagnostic info.

To get a feel for the severity of an individual's apnea, we often tell the person to set their machine at the lowest pressure setting (4.0 cm straight CPAP) and check their data the next morning. Of course, as you know, even at 4.0 cm some therapy is being delivered, but there is only a small subset of apnea patients who are treated effectively at 4.0.

such easily obtained diagnostic info (which I admit could be misused) as long as the alternative is a $5,000 sleep study.

More and more, we are seeing home sleep studies being used for the simple cases of obstructive sleep apnea. Check out some of the pricing - https://www.google.com/search?q=home+sl ... e&ie=UTF-8

Then there is the titration study which is, in recent years, being done frequently by using the auto function of an APAP.

So, it would seem the sleep lab may, in the future, be used only for the more difficult cases. Your vision is being implemented step by step. Economics dictates it.

As an aside, you've overestimated the cost of a lab PSG by a factor of 2 or 3. The last one I saw was $1700.

[Goofproof]

Keep one thing in mind when trying to separate the two functions... whatever your therapy 'result' can differ from night to night for lots of reasons, even if only a bit, so again, trying to get exact #'s to make comparisons is quite iffy - we're not machines .

And we are made from defective parts, many of which are wearing out! Jim

[palerider]

It does seem to me that, inherent in all Cpap devices, there is, first, a "detection" function. That is, through very elaborate statistical interpretations of solely basic respiratory data over time, the devices are able to make good guesses at a wide variety of apnea and apnea-related phenomena and their severity.

Once this is determined, there is, it seems to me, a "therapy" function in which, given the identified instances the automation has identified above, very sophisticated algorithms are applied (often modified and improved by long term trends) to apply the proper amount of pressure predicted sufficient to keep the airway open but not so much as to unduly disturb sleep. As an aside, to the extent that long-term trends are recognized, some of "today's" therapy addresses "yesterday's" problem - which is OK - averages are useful and important.

These are 2 incredibly complex jobs but, it seems to me they are, almost by definition, independent. I see no reason why the existing "detection" function can't be easily separated from the "therapy" function (by simply nulling all therapy activity) to increase available diagnostic info. Well, I guess I can - the medical establishment, for reasons good and bad, probably doesn't want to release its stranglehold on such easily obtained diagnostic info (which I admit could be misused) as long as the alternative is a $5,000 sleep study.

no, not really.

go read this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629962/

[Hannibal 2]

Keep one thing in mind when trying to separate the two functions... whatever your therapy 'result' can differ from night to night for lots of reasons, even if only a bit, so again, trying to get exact #'s to make comparisons is quite iffy - we're not machines .

And we are made from defective parts, many of which are wearing out! Jim

...and our detective parts are often blamed by some on the use of CPAP, my hearing and eyesight has definitely got worse since I started therapy