Flow Limits How to Upgrade CPAP to Bilevel

[AndyB]

Sleeprider -- your message above contains such important, informative and thoughtful information that it should be memorialized in the permanent threads at the top of this forum. I ALWAYS learn new things from you -- thank you!

AndyB

[Deborah K.]

Sleeprider,   Thank you so, so much!  

Here's a secondary question for whoever knows.  If we get this taken care of and are ready to order machines, if there are only card-to-cloud machines available, will whoever needs to see reports to prove compliance be able to receive the necessary reports? Also, am I right to assume that the card-to-cloud machines still have a slot for an sd card?

[Sleeprider]

AndyB, I inserted the information into a wiki here https://www.apneaboard.com/wiki/index.ph...Sleep_Test

Card to Cloud machines save you a lot of money and the data is still available over the air and by SD card. Resmed provides a software to share data https://airview.resmed.com/resources/hel...nnect.html

[GuyScharf]

fyi, I switched from an AutoSet to a VAuto with no repeat testing. I documented clearly how the AutoSet wasn't giving me relief and how a VAuto did (I was able to borrow a VAuto to confirm that it helped a lot). I also had a very good relationship with my doctor, so he was totally co-operative when I documented the needs and immediately prescribed a VAuto for me. A couple weeks later, the DME provided it.

[Sleeprider]

Deborah K, I updated the title of this thread to show the discussion concerning upgrading CPAP to Bilevel. Hope that is okay. It makes this topic easier to find in the future since we have many threads titled Flow Limits.

[Deborah K.]

We will both see our doctors soon to try to have bi-levels prescribed.  I have tidal volumes from 200-240, mostly 240.  I'm guessing I should take an Oscar screenshot showing 200 to the doctor.  Is that a good idea?  What is a normal/good tidal volume number?  Alan's is much higher, in the middle 400s to the middle 500s.  Maybe those are normal.  I don't know.

Should I sleep with no EPR a couple of times to show how I do with no pressure support?

Alan's machine is set at 17-25 pressure, and he does top out at 25 fairly often.  The idea that he should switch to a regular pap machine seems ludicrous to me.

Also, and this is just for general knowledge, I often get a 0.0 large leak rate on the left-hand chart, and I figure that's really good.  At what number should one begin to worry that the number is too high?  

 for all your help!

[Sleeprider]

Contrasting EPR with no EPR shows that bilevel pressure works. Zoomed screenshots showing flow rate, mask pressure and tidal volume should should help, especially where flow limitation is high, and inspiratory flow rate is flattened. Don't suffer too much, the main thing is to describe how you feel, and that you think additional pressure support would make a big difference. If you really want an adventure. put your husband on the CPAP to show how it changes his settings, and use his Vauto for a night with EPAP min 9.0, IPAP max 18.0 and PS 4.0. You can make two cases in one night, but it's not just the numbers. Document how you feel.

[Deborah K.]

I would still like these two questions answered:

1.  I often get a 0.0 large leak rate on the left-hand chart, and I figure that's really good.  At what number should one consider that the number is too high?  

2.   What is a normal/good tidal volume number?

[Sleeprider]

The "large leak rate" is a percentage of time large leaks are over the large leak threshold set in Oscar. This should vary depending on type of mask, but it is really where leak rates are large enough to where the CPAP loses control over the airway and unable to maintain set pressure and detect respiratory flow. That tends to be well above the "large Leak rate that is usually flagged at about 24 l/min. You will see that the large leak rate is actually a setting in Oscar under menu option File/Preferences/CPAP. I tend to look at the median leak rate in statistics. A leak rate of 0.0% is great, but I would not be too excited about anything under 5%, which for me is an action level.

Tidal volume varies between individuals based on height, age, health and other factors. A pulmonary function test is often used to determine if there are impairments that can affect lung volume. I tend to look at broad ranges of of tidal volume among individuals and will generally look for some reason if it is below 280 mL for women with minute vent under 4.0 L/min, 360 for men with minute vent < 5,0. Mine hovers around upper 500s to mid 600s. with Vm 9.5-10.2. There is such a wide range that it is very difficult to say there is even a range, but Vt can often be improved, sometimes significantly, when flow limitation is relieved by pressure support.

[Deborah K.]

So, are you saying you do not consider a leak rate that shows up as 4.50 as not worth worrying about?  I have seen people advising others that 0.10 or even 0.00 needs to be "fixed."  I gather that is not true at all.

On the minute vent issue, I'm a little under 4 on the Med chart.  I had pneumonia twice some years back, very badly the first time, not as bad the second time.  Could those have damaged my lungs a little, accounting for the low minute vent and the low tidal volume?  Or can better treatment with a bi-level solve these issues?