04-29-2016, 10:05 PM
(This post was last modified: 04-29-2016, 10:09 PM by Sleepless12.)
Question about using an auto machine for central apnea
Hello all,
I have both obstructive and central sleep apnea. The cause of my central sleep apnea is unknown as I was just diagnosed with both a few months ago. I was initialy using an auto CPAP machine, but the doc felt it was not effective so I am now using an ASV/BiPap machine. The issue is that the doc prescribed a BiPAP machine with a set pressure that is not adjusted throughout the night. That pressure was 19/8. I kept waking up during the night with extremely dry mouth (almost burning) and very thirsty. I was also having a lot of gas in the mornings. I spoke to the people at the sleep center and they switched me to an auto machine that adjusts the pressure throughout the night. I feel much better with this new machine. The machine says that my AHI is on average 1 or less per night. However, the doc says I should not believe the report as it's probably very inacurate and wants me to go back to a BiPap. He says I need to get used it. But I like the new auto device so I am unsure about what to do. Is the algorithm really that inaccurate in calculating my AHI?
Note: the auto machine says that on average my pressure is 12/8 that is why the doc feels uncofortable with it as the lab study showed that a pressure of 19/8 is necessary to remove my sleep apnea.
RE: Question about using an auto machine for central apnea
A couple of observations..
1. A one-night titration test is at best a snapshot in time, usually in a strange bed in a strange environment and wired up in an uncomfortable manner. It's good as a starting point for your pressure settings but no more than that, in my view. I'll go further - in most cases they are not really required but are a huge money-spinner for the industry and that's the sole justification for their existence (in most cases).
2. 19 / 8 is both a very high IPAP pressure to tolerate all night long, and reflects a very large pressure support. I'm not surprised you were getting gas (aerophagia) and that you were not sleeping well. This is the sort of pressure you'd experience when the machine is trying to force you to breathe through a central apnea. It's not the sort of pressure you want or need all the time.
3. What basis does the doc have for saying the AHI reported by the machine is inaccurate? This sounds to me a bit like the mystique defence - I'm the doctor, trained in the arcane knowledge which you mere patient couldn't be expected to understand. Either that or he is placing far too much faith in the titration result (see 1. above). By the way, what AHI did the biPAP machine report?
4. The ultimate purpose of CPAP treatment is to provide you with refreshing sleep, to allow your body to regenerate through the night and avoid unnecessary awakenings. Clearly this was not happening with the BiPAP but (maybe) is happening with the more sensible settings on the ASV.
5. ASV is the gold standard for treatment of central apnea. Nothing else comes close. ASV machines are expensive and often insurance requires you to try a BiPAP first and only move on to ASV if BiPAP fails. That doesn't sound like the issue here.
6. Get hold of Encore Pro software and SleepyHead (See the links at the top of this page). Use Encore Pro to generate reports to show your doctor. Use SleepyHead to monitor your progress - they both give similar information but from what I've heard SH is far more user friendly. Both programs allow you to view your breathing in great detail - show the charts to your doc and ask him to identify any unreported apneas.
You are your own best advocate. It's your health and ultimately your decision. If the doctor won't cooperate find another one. On the basis of what you've told us, your current doctor needs to learn a few things.
04-29-2016, 11:18 PM
(This post was last modified: 04-29-2016, 11:19 PM by Sleepless12.)
RE: Question about using an auto machine for central apnea
The ASV machine that I am using is being rented because the insurance will only cover the rental costs, which I am thankful they are doing as the machine is probably very expensive. It shows an AHI of 1.4 or less. I did discuss with the doc the fact that the titration study may not be very accurate as I only got an hour of sleep or so in the lab because I could not sleep with all the wires attached to me in a strange environment. I personalty feel that whatever apnea episodes I had were made worse by the fact that I was in a strange environment. In fact, I had no typical symptoms of sleep apnea before I found out that I had a very severe apnea with an AHI of 63. The doc, however, seems to view the titration study as the best way to determine what my pressure settings should be. I think there should be a balance. Even if my AHI is several points higher than what the machine reports, it's still much better than waking up with dry mouth and lots of gas. Unfortunately, my insurance does not cover another doc. I am a low income individual and cannot transfer doctors.
04-30-2016, 02:24 AM
(This post was last modified: 04-30-2016, 02:29 AM by vsheline.)
RE: Question about using an auto machine for central apnea
(04-29-2016, 10:05 PM)Sleepless12 Wrote: ... so I am now using an ASV/BiPap machine. The issue is that the doc prescribed a BiPAP machine with a set pressure that is not adjusted throughout the night. That pressure was 19/8. ...
I spoke to the people at the sleep center and they switched me to an auto machine that adjusts the pressure throughout the night.
Did they change you to a different machine, or did they just change the settings?
Can you tell us what is the model number (sometimes listed as "REF" number) on the machine? (Be careful not to move the machine without first removing the water tub.)
Quote:However, the doc says I should not believe the report as it's probably very inaccurate and wants me to go back to a BiPap. He says I need to get used it. But I like the new auto device so I am unsure about what to do. Is the algorithm really that inaccurate in calculating my AHI?
Note: the auto machine says that on average my pressure is 12/8 that is why the doc feels uncofortable with it as the lab study showed that a pressure of 19/8 is necessary to remove my sleep apnea.
It sounds to me like your doc does not have much common sense, because he is not listening to you and is discounting the information you are providing to him.
Also, I think his assumptions are largely unwarranted, because the AHI reported by the machines is usually pretty accurate, and overnight titration results are often not representative of our true pressure needs, especially if we were told to sleep on our back but normally only rarely sleep on our back. (Sleeping on our back is usually the worst sleep position for Obstructive Sleep Apnea.)
Stick to your guns, meaning, don't be bullied by your doctor.
Take care,
--- Vaughn
The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies. Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
RE: Question about using an auto machine for central apnea
If you are only going up to 12, does it matter much if the top end is set to 19?
RE: Question about using an auto machine for central apnea
(05-01-2016, 08:20 PM)player Wrote: If you are only going up to 12, does it matter much if the top end is set to 19?
G'day Player.
I think there are two machines involved here: 1) a BiPAP on fixed EPAP / IPAP, with the IPAP set on 19 at all times. 2) An ASV which Sleepless12 has on loan. The ASV is indicating a average IPAP of 12, but the doc wants him to go back to the BiPAP machine with a fixed IPAP of 19.
Perhaps the doctor would like to try sleeping with a fixed 19?
