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RE: Different AHI results between two CPAP machines
(11-22-2019, 10:05 AM)sopherFellow Wrote: Additional response to your comments about user insensitivity to events.
On a typical night I have zero events where my O2 drops below 90%. Nonetheless, I feel substantially more or less rested/tired on a day following a high/low number of events reported by my AirSense. O2 saturation is important, but it is not the whole story. Disruptive sleep, even if it does not reduce O2, may still prove to be unsatisfactory and non-restful.
You may be particularly insensitive to events - this might be because you are used to having events and you may have such a large sleep deficit that it will take quite a while for you to see improvement. So, I disagree that users in general are insensitive to events. I see a key question asked in virtually every thread on here (including this one) is "How are you feeling next day?" Once you overcome your sleep deficit acquired over a long period of time, perhaps you will find this a useful question as well.
Submitted for your consideration.
Dennis
P.S. Early days, but so far very impressed with the O2Ring. On the 1 occasion that I had an O2 drop, it's vibration alarm awoke me and I was able to fix the problem.
I agree that this is a useful question. However, my daily feeling is affected by many other factors.
Sleep Apnea has two main and independent problems: Disaturation events and arousals. Arousals break the sleep sequence and thus interfere with the brain maintenance process. While minimizing AHI will reduce disat events, I could not find anything that can help reducing the arousals.
(11-22-2019, 09:38 AM)bonjour Wrote: You have maxed out your pressure support by having EPR=3. I would set your min pressure to 7 as that will maximize your benefit at low pressures. That means your min pressures IPAP/EPAP = 7/4
Not sure I understand. Did you mean max pressure = 7?
Thanks,
Arik
11-22-2019, 10:49 AM (This post was last modified: 11-22-2019, 10:54 AM by ragtopcircus.)
RE: OSCAR and/or ResMed related question
(11-22-2019, 10:37 AM)Arik Wrote:
(11-22-2019, 09:38 AM)bonjour Wrote: You have maxed out your pressure support by having EPR=3. I would set your min pressure to 7 as that will maximize your benefit at low pressures. That means your min pressures IPAP/EPAP = 7/4
Not sure I understand. Did you mean max pressure = 7?
Thanks,
Arik
Your minimum pressure (IPAP) is 5. IPAP - EPR = EPAP. However, Resmed machines will never reduce the pressure below 4. So, at you minimum pressure of 5, EPR is effectively reduced to 1 (until apnea causes your pressure to rise).
However, the default minimum IPAP of 4 is too low for almost everyone except in pediatric use. Your minimum of 5 is still pretty low. As an adult, it is unlikely that you will need less than 7. Increasing your minimum pressure to 7 will leave enough room to allow EPR to function at the full requested 3 cmH2O.
(11-22-2019, 09:38 AM)bonjour Wrote: You have maxed out your pressure support by having EPR=3. I would set your min pressure to 7 as that will maximize your benefit at low pressures. That means your min pressures IPAP/EPAP = 7/4
Not sure I understand. Did you mean max pressure = 7?
Thanks,
Arik
Your minimum pressure (IPAP) is 5. IPAP - EPR = EPAP. However, Resmed machines will never reduce the pressure below 4. So, at you minimum pressure of 5, EPR is effectively reduced to 1 (until apnea causes your pressure to rise).
However, the default minimum IPAP of 4 is too low for almost everyone except in pediatric use. As an adult, it is unlikely that you will need less than 7. Increasing your minimum pressure to 7 will leave enough room to allow EPR to function at the full requested 3 cmH2O.
Exactly.
Gideon - Project Manager Emeritus for OSCAR - Open Source CPAP Analysis Reporter
(11-22-2019, 10:37 AM)Arik Wrote: Not sure I understand. Did you mean max pressure = 7?
Thanks,
Arik
Your minimum pressure (IPAP) is 5. IPAP - EPR = EPAP. However, Resmed machines will never reduce the pressure below 4. So, at you minimum pressure of 5, EPR is effectively reduced to 1 (until apnea causes your pressure to rise).
However, the default minimum IPAP of 4 is too low for almost everyone except in pediatric use. As an adult, it is unlikely that you will need less than 7. Increasing your minimum pressure to 7 will leave enough room to allow EPR to function at the full requested 3 cmH2O.
Exactly.
I see. Does this suppose to improve Flow Limitation?
11-22-2019, 12:45 PM (This post was last modified: 11-22-2019, 01:29 PM by Hydrangea.)
RE: Different AHI results between two CPAP machines
(11-22-2019, 02:55 AM)Arik Wrote:
(11-21-2019, 11:51 PM)Hydrangea Wrote: I have 2 machines: DreamStation Auto is my daily machine, and ResMed Airsense 10 AutoSet is my travel machine. I have them both tuned in to similar settings that make me feel similar symptom relief. But my ResMed always yields an AHI that's about half of the AHI on the DreamStation.
I've personally concluded that they must have their own proprietary way of counting AHIs, and thus why the numbers are so different.
This is a very important insight. Can you figure out which events make the difference? (for example: maybe both machines are quoting the same number of Apneas but Dreamstation is quoting many additional Hypopneas).
Thanks,
Arik
I can't figure it out. But I'm also not all that great at understanding what the data is saying.
I have learned that the machines don't record the same info. My ResMed 10 Airsense Autoset records Flow Limit, but my DreamStation Auto does not. But I don't know how that plays into AHI and how the companies decide what is AHI-worthy.
There is a thing called Central Hypopneas that is (shouldn't be) an optional parameter for PSG to evaluate for. None of our CPAPs evaluate for it.
A complete stoppage is easy to check for, there is no flow.
Hypopneas are a partial blockage or reduction in flow. The rule says 50 to 80% reduction in comparison to normal. What is normal? The obvious way is to take a moving average. Obviously if this average contains disturbed breathing the average is flawed.
This also applies at the 80 to 99% reduced breathing Apneas
Why all the above, because I believe the hypopneas criteria was met earlier than the flags and more often.
You have identified Central Hypopneas which you identified by spotting the typical cyclical breathing pattern of CO2 near the apneic threshold.
In a normally functional mask, any mask, the venting should be sufficient to prevent this. Should the vents be compromised in any way, such as condensation build up, which will increase CO2 in the mask and subsequently rebreathed. Note this CO2 buildup does not cause centrals, it treats them, at least where the CO2 apneic threshold is in play.
It is low levels of CO2 in the blood that suppresses our drive to breathe, not high levels as you suggest in your OP.
Seeing this pattern I recommend reducing the efficiency of your device to reduce the amount of CO2 being flushed from your system. This is best done by reducing EPR or PS or Flex depending on machine by 1
Gideon - Project Manager Emeritus for OSCAR - Open Source CPAP Analysis Reporter
Not sure I understand why it is low levels of CO2 in the blood that suppresses our drive to breathe, not high levels.
For this specific case, I was trying ResMed F30 for few days as a potential replacement for my FF Dreamware. It turned out that it increased my AHI by far (from less than 1 to 3-5), creating Centrals and Hypopneas that were not with the Dreamware. So I returned it back and trying now Amara View.
