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New to this - I'm not getting enough air
#41
Alan, my current settings are in my profile. I have both a Resmed Aircurve 10 Vauto and Philips Respironics BiPAP Auto (760). They each work a bit differently in terms of their auto mode and the way they manage pressure support. A bilevel machine basically lets you specify a minimum EPAP pressure, a pressure support (difference between EPAP and IPAP) or a range of pressure support in the case of PR BiPAPs, and a maximum IPAP. The relatively low exhalation pressure to inhalation pressure can be really comfortable, but in excess, it can also cause problems and be over-stimulating. Pressure support is not just for comfort. It can increase the respiratory tidal volume, and is specifically used to treat hypopnea and RERA that CPAP cannot address. CPAP is intended to treat obstructive sleep apnea, but bilevel has much more flexibility to support respiration and ventilation in ways CPAP cannot.

EPR settings in Resmed are the same as bilevel pressure support. The numbers 1-3 correspond to cm H2O of pressure relief. While pressure support may be any setting in bilevel, (usually 4-8), it is limited to 3 in the Resmed CPAPs. There is a lot more I could add to this, but hopefully that answers your question.
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#42
Thank you, but I would greatly appreciate this information:

Also what are your inhale and exhale pressure settings?

Thank you,

Alan
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#43
I start with IPAP/EPAP of 13.0/9.0 and the pressure can automatically rise to as high as 18/15. With Resmed PS is a constant. Originally it was set at 4.0, and I changed it 3.0 to limit CA events.

On the Philips machine, I use a variable pressure support of 2-5 cm, so it starts at 11/9 but can vary both in pressure and pressure support. So combinations like 14/9, 15/12, 18/13 and more are possible. I rarely if ever reach maximum pressure or pressure support.

Unlike CPAP, in bilevel, I think the Philips Respironics machines are more versatile and do a bit better job in auto mode. With regard to CPAP machines, I'm not impressed with Philips use of A-Flex or C-Flex as compared to Resmed's EPR, and I think the auto pressure algorithm is generally too slow for most OSA patients.
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#44
(12-07-2016, 11:38 PM)Sleeprider Wrote: I start with IPAP/EPAP of 13.0/9.0 and the pressure can automatically rise to as high as 18/15. With Resmed PS is a constant. Originally it was set at 4.0, and I changed it 3.0 to limit CA events.

On the Philips machine, I use a variable pressure support of 2-5 cm, so it starts at 11/9 but can vary both in pressure and pressure support. So combinations like 14/9, 15/12, 18/13 and more are possible. I rarely if ever reach maximum pressure or pressure support.

Unlike CPAP, in bilevel, I think the Philips Respironics machines are more versatile and do a bit better job in auto mode. With regard to CPAP machines, I'm not impressed with Philips use of A-Flex or C-Flex as compared to Resmed's EPR, and I think the auto pressure algorithm is generally too slow for most OSA patients.

Thank you. I'm pretty ignorant here, having learned of the existence of bilevel from you only a few hours ago. I read some Resmed PDF's online and they appeared to say that their EPR waveform was superior. If Resmed PS = 3 is the difference between inhale and exhale, am I right to assume that the same difference is given by my DreamStation with Flex = 3?

If so, I'm concerned that a different waveform is insufficient. I've timed my exhales as 2 to 3 seconds, during which I'm troubled by the effort it takes to exhale (with Flex = 3) for a couple of seconds. This makes me think that a better waveform would not be enough for me.

Also, you wrote, "Originally it was set at 4.0, and I changed it 3.0 to limit CA events." I'm afraid I don't know what a CA event is.

Incidentally, I'll ask Kaiser tomorrow if I can try one of their bilevel machines and see if it works better for me. So my questions may become moot.

Best,

Alan

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#45
The Dreamstation provide up to 2-cm pressure relief, and that is flow based. So if you have good strong inspiratory or exhalation flow volume, you will get hte full 2-cm. On the other hand if you have fairly weak or low respiratory flow, you will get less, regardless of setting. Also, the Flex pressure relief only lasts during the breathing transition. The pressure returns to the CPAP setting during exhale, and during inhale. See the figures below, and note how briefly, C-Flex and A-flex provide respiratory relief compared to Resmed EPR, which is like the bilevel VPAP pressure relief.

BiPAP pressure with biflex, compared to A-Flex flow waveform. Note in BiPAP that two distinct pressures are supplied. One for IPAP, and a lower one for EPAP. The BiFlex feature, smooths the transition between them.

[Image: biflex.jpg]

Flow vs Pressure in A-Flex. In A-Flex pressure and flow move roughly together. As the patient inhales, pressure increases as a function of flow to provide pressure support.

[Image: aflex_technology.jpg]

[Image: A-Flex-Easy-Breathing-CPAP.gif]

The Resmed EPR with Easy-Breathe follows your breathing, so the exhale pressure begins as you initiate exhale, and does not increase until you initiate the next inhale. On a Resmed, the pressure increases from its minimum amount to the therapuetic setting during the most active phase of inhalation. As the inhalation starts to slow down, the easy breathing technology starts to drop the pressure just a bit and it drops the pressure all the way through the most active part of the exhalation. This makes the pressure curve take on a "wave like" shape. Here is picture that shows how the easy breathing technology combined with the EPR/PS affects the pressure being delivered to the mask:

Resmed EPR with Easy-breathe:

[Image: Screen%20Shot%202015-04-29%20at%2011.39....evue5g.png]





Another manufacturer Fischer Paykel makes the Intellipap with SmartFlex. It provides a full 3 cm pressure relief from CPAP, and their chart is actually easier to understand.

[Image: intellipap-smartflex-setting-123-graph.jpg]
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#46
Many thanks for your detailed post. I appreciate the substantial amount of time that you spent to assemble this information.

I have also scheduled a session at Kaiser to try some bilevel machines. However they require that I take their home sleep study first (with wrist recorder). So my bilevel tryout session will be after that, on Dec 21.

Thank you again,

Alan
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#47
Hi All,

I'll probably be off this thread for a couple of weeks until I've tried some bi-level CPAPs.

I've returned my present CPAP for a refund.

Best,

Alan
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#48
(12-10-2016, 12:30 AM)Alan Adler Wrote: I'll probably be off this thread for a couple of weeks until I've tried some bi-level CPAPs.

Hi Alan,

I have a special version of bi-level PAP machine which occasionally does for me all the work of breathing.

I occasionally have Central Apnea, when I fail to make any effort to breathe. At those times my Adaptive Servo Ventilator (ASV) bi-level machine very quickly automatically increases Pressure Support (PS) as high as necessary to do for me all the work of breathing.

My purpose is not to suggest that you might want to try an ASV machine. My purpose is to show the effect of high values of PS.

How high would PS need to be, to do for us all the work of breathing? For people with healthy lungs like me (and probably you), around 10. (The units are cm H2O, as usual.)

I estimate that, for me, using PS or EPR of three would constantly provide about 30% of the work of breathing.

I have an unusually slow heart rate when I sleep, usually in the mid 40s per minute, occasionally dropping into the mid 30s. My SpO2 when asleep used to hover in the low 90s most of the night. SpO2 of 90% not considered too low, but now that I've increased my minimum PS setting to 5 I feel better in the morning and my SpO2 tends to hover between 94% to 96% all night, which I consider ideal.

My average Tidal Volume (average volume of air per breath) also increased closer to normal when I raised my Min PS setting to 5.

I suggest that you not use a PS setting so high that it causes your sleeping SpO2 to average higher than 96. When our SpO2 gets too high for too long it causes unnecessary oxidative stress, which accelerates aging and can interfere with prescription medications.

So please do use a recording oximeter occasionally to monitor SpO2 and avoid excessively high settings for PS.

Take care,
--- Vaughn
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. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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