RE: New Machine - Numbers Don't Match
(10-16-2017, 07:02 PM)Walla Walla Wrote: If I'm reading this right, here is what I Understand. Was using a BIPAP: EPAP 8 PS 2 IPAP max 15. Went to a Airsense 10 Sets pressure 8 to 15 with EPR of 2. That would put the EPAP at 6cm. That's 2cm below what he was using on the BIPAP. Starting off 2cm lower could be enough to collect those extra events.
Yep, that's what I said in post #9.
RE: New Machine - Numbers Don't Match
Thank you, and thank you for post #9. I have indeed adjusted my Resmed in accordance with your suggestions. I now understand that it is necessary to adjust minimum pressure higher to compensate for the differential of EPR if used in order to avoid OA. I'm new to this, and didn't immediately recognize the congruence of what you were saying and what was going on in the testing. I'm going to get some new data and share it along with the night that caused me to come to this forum. What still perplexes me, however, is in the testing, generating artificial apneas, the bench measurements of residual ahi and ai appears to differ substantially with what the machine itself was displaying. I wonder why. The lab calculated what the machine was doing to "therapize" the test it was being offered. The machine display was otherwise. Can the machine display be trusted? Is the actual AHI substantially lower than the display when, as in the test EPR 3 is selected.
Again, thank you!
RE: New Machine - Numbers Don't Match
Aardvark, it's hard to say what caused the discrepancy between what was measured on the bench test and what was reported by the device. The footnotes in that chart are very confusing to me, but I assume the "bench" pressure is representative of a direct mask pressure measurement. Both the A-flex and EPR3 tests resulted in higher pressures being reported by the device than the bench, and I don't know why pressure relief would affect that differently than constant pressure.
The study results could have been predicted by the design of the study method. For APAP machines, the apnea were implemented once each minute for 20 seconds. In real patients, apnea are often preceded by snores, flow limitations, and volume changes that the machines are designed to detect and implement pressure increases to prevent apnea. The test just smacked the devices with obstructive apnea and then continued normal breathing for 40 seconds to the next apnea. The comparison of titrated fixed CPAP against wide-open APAPs and devices with pressure relief has predictable results we see here all the time.
I have been surprised that manufacturers have incorporated patient accessible pressure relief features into devices, that can undermine a prescription. At the very least, there needs to be an expanded discussion in owner's manuals that discuss the impacts of using those features, or titration studies need to start anticipating people will go home and use those features. Of course most studies recommend a single pressure that is usually on the high side. People then go home and turn on Auto and pressure relief functions and undo all of that. In your case, you are converting bilevel pressures to a pressure relieving CPAP. The calculation to change PS to EPR is pretty simple, but it's really easy to get wrong as you found.
RE: New Machine - Numbers Don't Match
Hi folks. It took me awhile to master the screen shot imgur process. But now that I have, here's a post of the worst most recent night with Resmed Autoset. Saturday October 10. No alcohol, no cns medications, nothing. Mirage FX mask properly tightened and checked for leaks. Don't recall whether it was 19mm id or 15 mm but it was properly set, whatever. I was prescribed and use 2 liters/min of supplemental oxygen during the night because of the altitude (7200') That's new, but the same last night with my 750 Respironics was 5.59, however, that included a lousy one hour nap in the afternoon, so I suspect it was under 5.0 for the long night. Comments please?
10-20-2017, 05:53 PM
(This post was last modified: 10-20-2017, 05:54 PM by Walla Walla.
Edit Reason: deleted word
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RE: New Machine - Numbers Don't Match
It's looks like a soft cervical collar might help you. You maybe tucking your chin which cuts of the airway. The collar can help prevent that.
Also you look like you need a major increase in pressure. Say 15cm -20cm. You might want to consider a Bi-level Machine.
RE: New Machine - Numbers Don't Match
Thanks! I do use a cervical pillow for the same purpose.
RE: New Machine - Numbers Don't Match
I agree that the clusters of apnea look like a positional issue. What are the settings on the BiPAP 750? Your Sleepyhead chart does not match your pressure setting of 8-17, and both the chart and the statistics show your pressure reached only 15 cm (please minimize the monthly calendar). You may be using EPR at 2, and the statistics for some reason are only showing EPAP pressure.
Altitude can make a difference for some people, and we usually have seen people develop more central apnea. There is a possibility these events are improperly classified as obstructive, but I don't know of a good way to determine that from the machine or sleepyhead data. If you post a closeup of one of the apnea episodes, we might see something in the respiratory flow rate wave-form. Usually the best images cover about 2-5 minutes.
RE: New Machine - Numbers Don't Match
I have the Airsense Autoset 10 also. Just started a month ago.
I had some numbers that didn't make since a couple times, so I wore an oximeter to compare. (CMS 50)
Turns out the AHI on the oximeter was very close to the AHI on Airsense.
I recommend you do the same thing. Only way to check the accuracy of these things.
RE: New Machine - Numbers Don't Match
Great! Thank you.
RE: New Machine - Numbers Don't Match
I'm sorry. I'm complicating things. The Autoset was set to 8-15, EPR 2 for this snapshot. It was provided to me set to 4-15 no EPR. The 750 Bipap is at 8-17 Biflex 2, although I have experimented with ditching the Biflex and using a 200 millisecond rise, which seems to provides seemingly the same comfort (but doesn't affect EPAP or IPAP pressures?) I tried raising the IPAP on the Autoset, but I wound up with what I believe was pressure-induced dizziness. I didn't understand that because the Bipap can go that high without causing me any problem. I really want to work with the Resmed as the bipap has a million miles on it, and has had problems in the past. ButI am very confused. I've used the bipap for the last couple of days. Day before last, AHI was 5.5, last night 18 something. Everything the same. Again, no alcohol or medications that could effect things. I'll post another look at the above screenshot so we can see flow rates and will try to focus on an apnea as you suggested.
Thanks so much Sleeprider
Aardvark08
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