+- Apnea Board Forum - CPAP | Sleep Apnea (https://www.apneaboard.com/forums)
+-- Forum: Public Area (https://www.apneaboard.com/forums/Forum-Public-Area)
+--- Forum: Main Apnea Board Forum (https://www.apneaboard.com/forums/Forum-Main-Apnea-Board-Forum)
+--- Thread: How can CPAP treat hypoxemia (low SPO2)? (/Thread-How-can-CPAP-treat-hypoxemia-low-SPO2)
How can CPAP treat hypoxemia (low SPO2)? - asque - 10-26-2018
My study showed mild hypoxemia (oxygen desaturation unrelated to upper airway resistance). I had been using nocturnal O2 at 2 lpm with CPAP but because of Medicare restrictions he is trying to treat it by increasing the CPAP presure. How can this work?
The only idea that I have had is that the additional pressure reduces the effective altitude from 4300 feet above sea level to a lower value. However, some quick math with an altitude pressure chart indicates that the possible adjustment in effective altitude is only a few hundred feet while using normal CPAP pressures. The supplemental O2 gave me an effective altitude of sea level. I have not found anything online to explain how increasing the pressure above what is needed to reduce AHI to 0 (cmH2O=5) can be effective. Now BIPAP could increase tidal volume, but that is not the recomended action.
Finally, the chart on the study shows IPAP=EPAP at all pressures with the note "C-Flex:3+" How is this even possible?
RE: How can CPAP treat hypoxemia (low SPO2)? - Sleeprider - 10-26-2018
(10-26-2018, 04:28 PM)asque Wrote: My study showed mild hypoxemia (oxygen desaturation unrelated to upper airway resistance). I had been using nocturnal O2 at 2 lpm with CPAP but because of Medicare restrictions he is trying to treat it by increasing the CPAP presure. How can this work?
The only idea that I have had is that the additional pressure reduces the effective altitude from 4300 feet above sea level to a lower value. However, some quick math with an altitude pressure chart indicates that the possible adjustment in effective altitude is only a few hundred feet while using normal CPAP pressures. The supplemental O2 gave me an effective altitude of sea level. I have not found anything online to explain how increasing the pressure above what is needed to reduce AHI to 0 (cmH2O=5) can be effective. Now BIPAP could increase tidal volume, but that is not the recomended action.
Finally, the chart on the study shows IPAP=EPAP at all pressures with the note "C-Flex:3+" How is this even possible?
The correct way to treat this is with bilevel pressure support. You have precisely the wrong machine to do this. The solution is to document the poor efficacy, and let the doctor know you do not benefit from, nor tolerate CPAP and request bilevel titration. You may need to get an inexpensive oximeter to support the claim, see Supplier #19. Most insurance guidelines require a patient to use and fail CPAP before bilevel will be approved. It's insane, but as long as you understand this is SOP, you can shorten the process by complaining.
Here is some relevant reading http://www.apneaboard.com/wiki/index.php?title=Flow_Limitation/UARS_and_BiPAP
RE: How can CPAP treat hypoxemia (low SPO2)? - asque - 10-26-2018
I'm not sure we are using the same definition of "tolerate". On paper the CPAP looks to be 100% effective until you include oximetry readings. Unfortunately, the latest iteration windows 10 will not recognize my CMS50D+, it refuses to even load the driver! The link you gave appears primarily to address the issue of non-usage of CPAP by using bi-level support. Since usage is close to 100%...
Part of the frustration with the sleep study is that if you know that you are testing someone who falls asleep at 2 AM, sleeps 1.5-3 hours , wakes up for an hour or so, (and drinks a cup of coffee to go BACK to sleep), sleeps to about 9 AM, drinks more coffee and then falls asleep again, you might want to adjust the testing so that you are at the pressure you are prescribing for more than 19 minutes! Of course that is another mystery-why coffee is a sleep aid for me.
RE: How can CPAP treat hypoxemia (low SPO2)? - Walla Walla - 10-26-2018
Since your problem with O2 seems to be unrelated to sleep apnea I'd recommend making an appointment to see a Pulmonologist about the O2 problem. I think you'd have a better chance of getting what you need in regards to treatment. Not saying that CPAP isn't good for sleep apnea but you have needs that go beyond a sleep center expertise.
RE: How can CPAP treat hypoxemia (low SPO2)? - mesenteria - 10-26-2018
I take it that your lungs have checked out and that your haem iron levels are also good? CPAP is meant to provide more efficacious breathing, and a secondary benefit is that your oxygen levels get better as a result. If you have other problems, you will have to deal with them as well.
About the few hundred feet. My youngest brother failed to thrive as an infant when we joined a mining corporation at altitude in the Peruvian Andes many years ago. We were at 14K feet. Within a year we were moved to a camp that was at 11K feet and the results were miraculous and turned him around. Perhaps a 'few hundred' feet may sound largely insignificant, but they are not in some cases. It depends on the nature of the deficit.
RE: How can CPAP treat hypoxemia (low SPO2)? - srlevine1 - 10-26-2018
(10-26-2018, 09:20 PM)asque Wrote: Unfortunately, the latest iteration windows 10 will not recognize my CMS50D+, it refuses to even load the driver!
Are you sure you have the latest version of the software?
Are you sure that you were using administrator privileges when you attempted to load the software?
Did you check that there was no conflict in your computer's device manager?
Did you check that you had previously uninstalled software and re-booted before re-installation?
Have you asked on the device vendors for assistance?
RE: How can CPAP treat hypoxemia (low SPO2)? - asque - 10-27-2018
Thanks for the replies, but no answers to the basic question. Sleep doctors are like the guy who only owns a hammer, so every problem must be a nail. Seeing a Pulmonologist is possibly the best answer, but since I am planning a move that will shave almost 3,000 feet off of the altitude within the next six months, so not something I would want to do now. The lower altitude may well resolve the issue. At his point, I just need enough good nights-and days- to fix up a house to sell. Fortunately, spending $400 for a rebuilt concentrator was an option I was willing, and able to take. A two hour nap with O2 was more refreshing than 7 hours without.
The CMS50D+ seems to have been designed back when RS232 serial ports were still widely used by the medical community. The driver allows the USB port to act like a serial port. Problem seems to be that Microsoft is blocking anything that does not give the correct response to their "plug and play" standard that was released after the CMS50D+ was designed.
RE: How can CPAP treat hypoxemia (low SPO2)? - srlevine1 - 10-27-2018
Have you verified the correct cable?
Are you aware of this resource? https://rehmann.co/blog/drivers-pulox-contec-cms50d-cms50e-cms50f-and-cms50i/
Steve