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+--- Thread: [Pressure] Widely varying pressures question (/Thread-Pressure-Widely-varying-pressures-question)
Widely varying pressures question - Heyns - 02-25-2018
Hi All,
I am relatively new to CPAP and sleeping well
One big negative is that my machine is not compatible with SleepyHead, so I have to go on the figures that I get from the machine and the very limited cellphone app . My "provider" also "provided" only until I bought the machine and accessories, after that they are much less responsive to questions than before. I guess that they cater for the uninformed masses who do not ask too many questions. Also, it seems to go about "the sale" primarily
What I have seen this far is that CPAP works well for me (as could be expected). One puzzling aspect is that the pressures from night to night keep varying. One night it will be 7.0 - 7.5 (90% - 95%), while it may be 12.0 - 13.5 just the following night. The AHI values are good.
1) Is this "normal"?
2) What is the significance of this? Should it not stabilise at SOME value (range)?
3) I assume that it is "better" to have a smaller 90% to 95% spread, rather than a large difference?
4) What causes this shift between nights?
Luckily the autoPAP adjusts to this, I just hope that it does so sensibly (but cannot see any graphs to confirm).
One last question: what is the "time in exhale puff" (provided as a % by the machine)? I understand the definition thereof, but it does not make sense to me when that figure is not zero when using a FFM, as exhaling through the mouth cannot be detected when using a FFM. When I use the Nose Mask I understand the issue, but I keep wondering whether it is correct when looking at figures when wearing the FFM.
RE: Widely varying pressures question - Sleeprider - 02-25-2018
I would suggest moving your minimum pressure higher to avoid the larger swings. A minimum pressure of 7.0 should even things out nicely. If AHI is already good, you will find less pressure swing to be less disruptive to your sleep.
Exhale Puff and the Exhale Puff Index are unique to Devilbiss.
EPI: The Exhale Puff Index (EPI) is the number of exhale puff events detected per hour. Exhale puffing is caused by inhaling through the nose and exhaling through the mouth. There are no published standards for exhale puffs but less than 100 per hour is acceptable, which equates to less than 2 per minute. If the EPI is higher than 100 this puffing should be addressed, perhaps through the use of a full face mask or chin strap. NOTE: This only applies to DV5x series data.
% Time in Exhale Puff: The % Time in Exhale Puff is the percentage of time a patient spent experiencing Exhale Puffing events. Exhale puffing is caused by inhaling through the nose and exhaling through the mouth.
RE: Widely varying pressures question - Heyns - 02-25-2018
Thank you, Sleeprider. How can exhale puffing be explained with a FFM? There is no way that the machine can detect it, but it still provides a value...
RE: Widely varying pressures question - Sleep2Snore - 02-25-2018
I agree, take your lower pressure up a bit at a time until the swing in pressure gets a lot less and if you take it high enough you might find a lot of the AHIs will stop. The machine should cover the others and will catch it quicker if the low pressure is a bit closer to what you require.
RE: Widely varying pressures question - Sleeprider - 02-25-2018
I'm only speculating, but I suspect it is a higher flow rate during exhale than would be expected with nasal breathing. The Begginer's Guide to Sleepyhead has some examples of flow rates. In this case the next-to-last wave form is what is expected with expiratory mouth breathing, and this may be what the Devilbiss looks for.
![[Image: Flow_limitation_images_zpsdb148d1f.jpg]](http://www.apneaboard.com/wiki/images/d/df/Flow_limitation_images_zpsdb148d1f.jpg)
I suspect that this more chaotic chart posted by MyronH is expiratory mouth breathing of some kind, so the pattern may look different among different individuals.
RE: Widely varying pressures question - Heyns - 02-25-2018
Thank you, Sleep2Snore and Sleeprider!
I think that you are right, Sleeprider. I do not have graphs, but I recognise the pattern when looking at the graph that you refer to. However, I think that I do a number of normal inhalations with shallow exhalations, followed by a deep exhale. I am quite sure that there is no mouth breathing. The air has to go somewhere, though. Hence the deep, fast exhale. TI think the DevilBiss detects this as exhale puffing. It would be interesting to see graphs of my data. I might be able to get some, but I do not have any compatible software. My sleep lab can possibly provide some graphs from the data on the SD card in the machine...
RE: Widely varying pressures question - trish6hundred - 02-25-2018
Hi Heyns, WELCOME! to the forum.!
Good luck with CPAP therapy.
RE: Widely varying pressures question - Heyns - 02-26-2018
(02-25-2018, 07:06 PM)trish6hundred Wrote: Hi Heyns, WELCOME! to the forum.!
Good luck with CPAP therapy.
Thank you!