Switching from CPAP to APAP

[icyura10]

Since my pressures are the same over 2 different machines, and I'm getting slightly different AHI numbers, I've been assuming the differences were due to internal sensing algorithms.

Could be, but it might be buried more within the hardware that does the timing aspect.

Many of these devices have CDMA interfaces to CELL towers and i can easily see during normal communications they sync their respective clocks to the CDMA time. That being said, it's not beyond possibility the clock inside the device could easily drift with wide variations and I can only suspect the CDMA interface may not be linked all the time like a cell phone, but rather, only when it needs to send data.

We all know that when our cell phone id "out of range" and has "no bars" for connection, the phone goes wild constantly searching for a cell to connect and sync up with for more than just receiving a phone call.

In many regards, it's akin to why computer system want to touch "certified" time sources periodically to ensure their dates and times are correct... within the all famous "N" units of time!

So, yes I've been fixated on that.

And without taking the bloody thing completely apart and finding all the parts where the timing mechanisms are for the purpose of providing timing to the various sensors, we'll never really know.

I can see a direct correlation between how I feel on a given day and my AHI score of the night before.

I can look at my score in the morning and tell if I will have a good day or not.

What happens if you were to keep a journal for say 14 days without looking at your reports or the score on your machine, then 14 days later compare your notes with the results of the machine or what software might present?

Could this be a self fulfilling prediction... based upon suspect information?

[KSMatthew]

No LOL. Your in sort of a special situation,

My guess was the Dr gettin his shorts in a knot or a DME,
Got me good on this one LOL

In case anyone else is interested:

In the US, the FAA has recently made some changes in how it handles OSA. I don't know how it works in Canada, Europe, or Australia. CSA is a special problem because it is a central nervous system issue, and FAA has some real trouble approving someone with that. OSA is much simpler to deal with - either your CPAP treatment is working or it isn't.

The way it used to be: If you suspected you had OSA, then got a diagnosis, you had to report it. FAA would want copies of reports, sleep studies, and 90-days of compliance data. You had 90 days to get as much of this together as possible and send it in. FAA would review it and then approve you (or ask for more info) and that review could take 3-4 months. In all that time, you were grounded. For anyone that flies for a living, those 6+ months were generally at a significant loss of income. The potential was that someone that suspected he had OSA would rather live with it than report it. There's no way to know if that happened. Once approved, you needed an annual report showing continued compliance and efficacy.

Last year, FAA changed the rules. If you report it, you can get approved right away and fly, but you will need all the documentation for final approval. Once that final approval comes, you are still under the annual renewal requirements afterward. But, if that approval DOESN'T come, THEN you are grounded until you get things fixed. FAA also started screening pilots for BMI (>= 35) and neck circumference (>=17") risk factors. If you meet those risk factors you are told you need an apnea screening. If that screening shows evidence of sleep apnea, then you need a sleep study and follow up compliance reports - but you are allowed to fly until then.

This year, FAA changed their compliance reporting requirements. It used to be a 90-day report showing "compliance" and the normal insurance reports were sufficient. Starting this year, the reports must show a full year of compliance at >6hrs/night, not the >4hrs/night that insurance generally requires. I had to dump my Devilbiss because it was not Sleepyhead compatible and couldn't show >6hrs counts - it also has some other problems with long term data, anyone with a Devilbiss that uses their SmartCode and wants more info can PM me. Now I have the new Dreamstation and Sleepyhead, and I have a whole lot more info than I've ever had before.

As far as making the switch from CPAP to APAP: It's more of an opportunity for me to see if it makes a difference without going into a new sleep study. Maybe changing pressure settings makes a difference, maybe not. But my new machine does have the capability for me to find out. There might be a way for me to test that, but I have to follow rules that most people don't live under. I've already had one FAA doc tell me that I should just leave well enough alone and that playing around without a doctor's supervision might result in "problems" later.

[icyura10]

Two thoughts.

While more data may be useful for you, it might cause the FAA to continually ask for additional information. Require cardiology, neurology, pulmonary or other certifications as evidenced by stress tests they may not be really requiring now.

There are ?PAP's that provide a minimal of data. AHI and basically pressure only.

Using a device that is very limited in the data it collects and reports might be in your best interest.

I find all the changes interesting and it's not just the FAA. Many state motor vehicle licensing agencies are starting to ask for similar data and for some 90 day's may or may not be adequate to satisfy their requirements.

I had sleep study where my AHI was above 120 and one state just about had puppies and drove my poor physician nuts with all the mandatory paperwork.

Fortunately I no longer reside there and haven't those issues any longer, but I'm sure, in these times of the NANNY state, it's going to catch up with me at some point in time. That's not to say I'm not using my therapy every day because I do.

My problem has always been the amount of sleep I get within any contiguous block of time. I only get at most 4 hrs and most of the time it's in the 45 - 120 minute block of time.

[KSMatthew]

Two thoughts.

While more data may be useful for you, it might cause the FAA to continually ask for additional information. Require cardiology, neurology, pulmonary or other certifications as evidenced by stress tests they may not be really requiring now.

There are ?PAP's that provide a minimal of data. AHI and basically pressure only.

Using a device that is very limited in the data it collects and reports might be in your best interest.

What I get from my machine and what I report to FAA can be two different things. All I am required to send in each year is a compliance report for the year and a status report from my treating physician. FAA doesn't require anything more and since they didn't ask, I'm not telling. But they do look at the data and changing a pressure setting without a corresponding report that explains why is a problem.

The interesting thing about Sleepyhead, it can create exactly what FAA wants (a 365 day bar chart of > 6 hrs) and because of that, many pilots use it and FAA is familiar with it. Score one for SH.

[OMyMyOHellYes]

Who is providing counsel regarding what the FAA is looking at and for and saying this will cause problems? Is it speculation or someone that actually works these issues daily? You may likely have done this, but talk to the Medical branch at the AOPA (Aircraft Owners and Pilots Association) for specifics. When I spoke to the folks at AOPA, they said (I'm paraphrasing) that the FAA doesn't really care about the pressure or a switch from CPAP to APAP - they just want to see compliance and efficacy if required to use PAP therapy.

I seriously doubt that the FAA is concerned about what your pressures are. They want to see that you are compliant (6 hrs, 80%) and that the treatment is effective.

For folks not familiar with aviation related apnea issues, AOPA's website has a summary on current FAA guidelines:

https://www.aopa.org/go-fly/medical-reso...-disorders

(As a non-commercial resource, I believe this link fits Apnea Board's criteria as an educational resource - AOPA is regarded as THE professional resource for aviation medical issues and working with the FAA (at least on a broad basis))

OMMOHY

[KSMatthew]

Who is providing counsel regarding what the FAA is looking at and for and saying this will cause problems? Is it speculation or someone that actually works these issues daily? You may likely have done this, but talk to the Medical branch at the AOPA (Aircraft Owners and Pilots Association) for specifics. When I spoke to the folks at AOPA, they said (I'm paraphrasing) that the FAA doesn't really care about the pressure or a switch from CPAP to APAP - they just want to see compliance and efficacy if required to use PAP therapy.

I seriously doubt that the FAA is concerned about what your pressures are. They want to see that you are compliant (6 hrs, 80%) and that the treatment is effective.

AOPA's website has a summary on current FAA guidelines

https://www.aopa.org/go-fly/medical-reso...-disorders

(As a non-commercial resource, I believe this link fits Apnea Board's criteria as an educational resource - AOPA is regarded as THE professional resource for aviation medical issues and working with the FAA)

OMMOHY

I'm very familiar with AOPA medical. If you know who Doc Bruce is, he's the guy that warned me about self titrating. The FAA letter says something like "any change in data may require a new sleep study" (again, paraphrasing). They don't specify exactly what they are looking for, but sometimes it's easier just to leave things alone.

>>
They want to see that you are compliant (6 hrs, 80%) and that the treatment is effective.
<<

And that's the area to be careful of - if it's effective, why change? If you changed, why did you change?

[Sleeprider]

Different machines can certainly deliver different results. I don't think it should be a problem at all for you to call your doctor's office, explain your plan to use a minimum pressure of 7.0 in auto-CPAP mode with a maximum pressure of 9-10 to clear up residual ahi. It could be as simple as the need for more pressure when you change positions, are in a different sleep stage, or have a cold. The reason isn't important. You are effectively treated at 7.0, but think you can do better. Make it happen.

[KSMatthew]

Different machines can certainly deliver different results. I don't think it should be a problem at all for you to call your doctor's office, explain your plan to use a minimum pressure of 7.0 in auto-CPAP mode with a maximum pressure of 9-10 to clear up residual ahi. It could be as simple as the need for more pressure when you change positions, are in a different sleep stage, or have a cold. The reason isn't important. You are effectively treated at 7.0, but think you can do better. Make it happen.

That pretty much nails it, and brings this back to my original question:

What's a decent, common sense, number for an upper limit? And how would that be determined?

[Sleeprider]

The APAP is self-titrating and reports its efficacy. Common sense says, use your CPAP pressure of 7.0 as a minimum so you cannot be backing off what already works. APAP will only increase pressure if it detects flow limitation, snores or volume changes indicative of obstruction, and then it will only increase the pressure enough to alleviate that symptom, then return to minimum pressure. These changes occur pretty slowly which is why the minimum APAP pressure needs to be close to your optimum treatment pressure.

If you set the maximum to 20, it wouldn't make a bit of difference. The machine would only go as high as necessary to eliminate obstruction. A prudent maximum with your history is 10 cm. A 3-cm pressure change is not disruptive to your sleep, and will likely resolve residual apnea and hypopnea without causing complications.

[KSMatthew]

The APAP is self-titrating and reports its efficacy. Common sense says, use your CPAP pressure of 7.0 as a minimum so you cannot be backing off what already works. APAP will only increase pressure if it detects flow limitation, snores or volume changes indicative of obstruction, and then it will only increase the pressure enough to alleviate that symptom, then return to minimum pressure. These changes occur pretty slowly which is why the minimum APAP pressure needs to be close to your optimum treatment pressure.

If you set the maximum to 20, it wouldn't make a bit of difference. The machine would only go as high as necessary to eliminate obstruction. A prudent maximum with your history is 10 cm. A 3-cm pressure change is not disruptive to your sleep, and will likely resolve residual apnea and hypopnea without causing complications.

Thanks - makes good sense.