ASV flow rate - it is not ventilating?

[bemused]

ASV users, do you ever show ~zero Flow Rate when you are close to or at maximum absolute pressure? This data image is one event from an hour long identical sequence. It appears to show I am NOT being ventilated, is that so? (epap=10, maxPS=8, so max ipap=18)

Sorry if I am being repetitive, I really want to understand how my S9 Adapt treats Centrals.

Bumped image from my previous thread:

[JohnBFisher]

You will note that the pressure goes to maximum (for you). While the flow rate appears go fall to zero, it does move some of the air in your lungs. The ASV units are not as forceful as a ventilator, so the flow might not be much. If your sleep is not improved, you might want to talk with your doctor about this. I will also check the clinicians manual. The flow rate may only capture the flow resulting from YOUR breathing. So with the increased pressure actually causing some flow, it might remove it from the data. I will check on that.

[JohnBFisher]

I think my previous assumption is correct. The Clinicians Manual calls it "Flow Limitation" not "Flow Rate". It implies that it measures your breathing effort - not the flow through the tube. As the pressure increases, it will help ventilate you. It might not be as much as normal respiration. However, it is enough to help purge some of the CO2 that builds up in your blood stream. This helps cut short the series of events that lead to continuous central apneas.

Hope that helps.

[Qzfgu]

Thanks,
I know you are prone to long Centrals, are you able to see on your data when they are being treated? Your max ipap is 25, does it ever get that high? I know each patient is very different and wil be discussing with RT later this week, just want to understand how it is intended to work first.

[bemused]

Oops, was not logged on. Previous post was me, of course.

[JohnBFisher]

Thanks,
I know you are prone to long Centrals, are you able to see on your data when they are being treated? Your max ipap is 25, does it ever get that high? I know each patient is very different and wil be discussing with RT later this week, just want to understand how it is intended to work first.

I have an older version of both the Resmed and Respironics units. They did not include the detailed waveform data. So, no I do not see the individual apnea events. However, I do know that my machine gets to 25cm H2O. It's one reason I struggle with mask leaks. In fact, I set a range for the EPAP on the Respironics unit, so that pressure can reach 30cm H2O - though that high is fairly rare. I have to have had obstructive apneas AND central apneas at the same time. Oddly, I don't seem to have that occur. The obstructive apneas occur more frequently during REM sleep and the centrals occur more frequently during non-REM sleep. (REM sleep relaxes our muscles, so obstructive apneas are more pronounced during that type of sleep. However, REM sleep increases the neural activity, so the problems with my brain stem are reduced during REM sleep .. thus, I have fewer central apneas during REM sleep. At least that's what I understand from when I discussed this with my neurologist.) So, the two types of apnea rarely overlap.

And yes, as you note, I stop breathing for a minute or more at a time. Yikes! (Of course, I think that's what killed my first ASV unit ... The bearings wore out, I suspect from almost two years of those apneas). Fortunately, the ASV unit makes a HUGE difference. I wake most mornings quite clear headed and without the morning headaches. My machines tell me that my AHI tends to run less than 5 almost all the time. Since I feel well, I don't monitor the data except to periodically (quarterly) check it.

Hope that helps.