Using CPAP machine as performance monitor

[Billy 54]

Hi All,

How do you do? Please allow me to introduce myself; I am Bill, a 65 year old male residing in the UK and I am the proud owner of OSA. I have been using a Resmed S10 Autoset CPAP machine since February 2018 with reasonable results (AHI almost always below 5). For reasons various I would prefer an alternative to the machine, hence, I have now been fitted with a Mandibular Advancement Device. I have a sleep study booked for about four weeks time but in the meantime I would like to be able to assess the performance of the MAD using my machine, could I please ask if anybody on the forum has used their CPAP machine for this purpose and if they have, could I please ask what pressure settings they set on the machine? I would also be grateful for any other additional information that members feel may be pertinent to my quest. Thanks to all in advance. Bill

[ChicagoGranny]

Welcome to the forum. It's a great aid in helping people get their CPAP therapy optimized and becoming comfortable with it.

could I please ask if anybody on the forum has used their CPAP machine for this purpose and if they have, could I please ask what pressure settings they set on the machine?

You could set the pressure at minimum 4 cm/maximum 20 cm. If the machine raises the pressure during the night, it's an indication your MAD is not effective.

If the machine stays at pressure 4, the results are inconclusive. This is because at 4 cm you are still getting CPAP therapy.

For reasons various I would prefer an alternative to the machine, hence, I have now been fitted with a Mandibular Advancement Device.

How severe is your condition (AHI)? What are your machine pressure settings? Have you optimized your CPAP therapy using OSCAR or Sleepyhead? Since you say your AHI is under 5, it sounds like your CPAP therapy is not optimal.

MADs work for a few people. But, CPAP is the gold standard, and nothing else comes close.

[D.H.]

I'm not sure why you want an MAD. Perhaps we could have a better answer if knew that.

Also, I'm not aware of anybody who treats OSA with an MAD and CPAP at the same time. Sometimes, patients need to take more than one medicine for an illness, so perhaps two simultaneous treatments for OSA is reasonable.

[Billy 54]

Hi,

Thank you very much for your quick reply. Please find below more information.

Before I started using the MAD my minimum pressure was 11 the maximum was 17.4. When looking at my results on Sleepyhead my 95% max pressure is usually between 11.5 and 13. I received my MAD last Monday and on the first night I kept the min pressure at 11 and reduced the max to 15, I achieved a AHI of 1.2. The second night I reduced minimum pressure to 9 and the max to 13, I achieved a AHI of 0.85. On the third night I set the min pressure to 7 and the max to 12.4, my AHI rose to 5.5.

I am a mouth breather and when on CPAP alone I usually tape up, I have not used the tape since receiving the MAD. Looking at Sleepyhead; on the first night I had a leakage rate of 1.73%, the second night 1.08% and on the third night 11.5%. So by the looks of things I managed to keep my mouth shut (that's a first) on the first two nights, but not on the third night.

The first two nights results show no clear airway events which I believe are also known as central events, but the third nights results show 1.91 and also CSR of 4.56%.

With regard to the severity of my SA, on my initial sleep study my AHI was 36, but at the time I was the proud owner of Atrial Fibrillation; following a successful cardioversion I underwent a further sleep study and my AHI was 14, it was at this point that I asked to be considered for a MAD.

According to my orthodontist MAD devices have a success rate of 85%, I'm ever hopeful that I will fall into that category.

I do not want to use the CPAP and MAD simultaneously as treatment I would just like to use the CPAP to ascertain whether or not the MAD is working. I have what is termed an adventurous lifestyle and I travel extensively, things would be made so much simpler if all I had to take with me was a MAD.

Thanks again for your help and I look forward to receiving your reply.

Bill

[Pugsy]

To know for sure exactly how effective just the MAD might be you are going to need a sleep study done using the device and nothing else.

The closest you can come with the machine is using a minimum of 4 cm and see what the machine records.
Most machines won't go below 4 cm....though I think the DeVilbiss has a 3 cm lowest setting available.
You may or may not get a clear cut answer using the machine at its minimum and the device...
if you have a really high AHI in terms of OAs and hyponeas...you will have your answer
if your AHI is still low...all you know is that with the device 4 cm does a good job but it doesn't tell you just how good of a job because there is therapy value even at 4 cm.

[Billy 54]

Hello Pugsy,

Thank you for your reply. If I set the minimum pressure to 4, what about the max pressure?

Thanks,

Bill

[Jay Aitchsee]

According to my orthodontist MAD devices have a success rate of 85%, I'm ever hopeful that I will fall into that category.

You may want to do a little more research. Many describe success of MAD to be an AHI less than 20 with a 50% decrease, as in this paper:
https://www.ncbi.nlm.nih.gov/pubmed/19451462

If your untreated AHI of 14 was reduced to 7 with MAD, it would be considered a success. However, not many on this forum would consider that a success. Most of us would like to see an AHI around or under 1.0.
Now that said, from what you've indicated as results, it may be that using the MAD with CPAP, in your case, may produce satisfactory results (by forum standards) even if not considered ideal by your standards. In that regard, many of us travel extensively with our CPAP machines without problems.

[Pugsy]

I know CG recommended 4 min and leave the max open just to see what the pressure would do but that's not what I would do if I was in your shoes. Too many times the machine might want to increase the pressure to try to kill something that might not be that big of a deal if it wasn't killed. I would rather see what happens with a strict minimum fixed pressure.

I would set minimum to equal max and make it fixed pressure.

[Goofproof]

I know CG recommended 4 min and leave the max open just to see what the pressure would do but that's not what I would do if I was in your shoes. Too many times the machine might want to increase the pressure to try to kill something that might not be that big of a deal if it wasn't killed. I would rather see what happens with a strict minimum fixed pressure.

I would set minimum to equal max and make it fixed pressure.

Also turn off, exhale pressure relief! Jim

You best bet is make XPAP work, you will live longer.

[Pugsy]

At 4 cm fixed there is essentially zero exhale relief available with all brands.
With Respironics Flex exhale relief doesn't even start unless the pressure is at least 6 cm.
With ResMed the EPR has no where to go at 4 cm fixed...so it doesn't really matter if on or off.
Pretty sure that the same thing applies to other brands.
If the machine is already at the lowest pressure possible then any exhaled settings simply become a moot point because there is no where for the machine to drop for exhale relief.

[D.H.]

The success rate of CPAP is very high, but that's only for those that use it. I think that this is a self-selecting population. Therefore, the numbers (while technically "accurate") are not reliable.

[alexander]

Let met ask what might be a stupid question. Not saying OP should do it, but if —

• The machine is in CPAP mode (not APAP!)
• The pressure is at a fixed point where one can breathe comfortably (somewhere near 4.0)

Wouldn’t that be sort of a poor person’s sleep test? In theory – shouldn’t that be able to measure the effectiveness of a MAD? And without a MAD, shouldn’t it be able to figure out the untreated AHI?

[Pugsy]

Let met ask what might be a stupid question. Not saying OP should do it, but if —

• The machine is in CPAP mode (not APAP!)
• The pressure is at a fixed point where one can breathe comfortably (somewhere near 4.0)

Wouldn’t that be sort of a poor person’s sleep test? In theory – shouldn’t that be able to measure the effectiveness of a MAD? And without a MAD, shouldn’t it be able to figure out the untreated AHI?

Very poor man's sleep study....believe it or not but people can have their OSA be totally treated with as little as 4 cm fixed pressure.
Depending on brand of machine we might still want apap mode with minimum to equal max (makes it a fixed pressure) because some machines don't flag everything that might be important to know about in cpap mode but they do flag it in apap mode. That is why I suggest keeping apap mode but just making it function like fixed mode....and I don't know if the OP here is using the machine where it matters.

The ONLY way to know for sure with 100% certainty just how effective the device is....another sleep study without cpap.

[Goofproof]

At 4 cm fixed there is essentially zero exhale relief available with all brands.
With Respironics Flex exhale relief doesn't even start unless the pressure is at least 6 cm.
With ResMed the EPR has no where to go at 4 cm fixed...so it doesn't really matter if on or off.
Pretty sure that the same thing applies to other brands.
If the machine is already at the lowest pressure possible then any exhaled settings simply become a moot point because there is no where for the machine to drop for exhale relief.

OPPs! Jim

Correct, Didn't think that one out.

[alexander]

Very poor man's sleep study....believe it or not but people can have their OSA be totally treated with as little as 4 cm fixed pressure.
Depending on brand of machine we might still want apap mode with minimum to equal max (makes it a fixed pressure) because some machines don't flag everything that might be important to know about in cpap mode but they do flag it in apap mode. That is why I suggest keeping apap mode but just making it function like fixed mode....and I don't know if the OP here is using the machine where it matters.

The ONLY way to know for sure with 100% certainty just how effective the device is....another sleep study without cpap.

Thanks for sharing your knowledge! I thought near 4.0 was considered breathing in air in a room, i.e. a sort of neutral pressure, but now I know better.