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+--- Thread: Flowgram looks like sonar pings (/Thread-Flowgram-looks-like-sonar-pings)
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Flowgram looks like sonar pings - bernardc - 10-23-2024
I'm a longtime PAP user, but first time poster, and just getting into the magnificent power of the Oscar data and UI. I'm using a borrowed DreamStation BiPAP AVAPS because I've been having central apnea and I'm using the machine's backup breathing rate feature. Last night's data (attached) seems alarming. The flow seems to peter out to nothing, even as the timed breathing activates.
- Am I reading this right?
- Does the AVAPS machine have an ASV algorithm? It doesn't seem to put more than IPAP and EPAP pressures on the timed breaths, inadequate to produce the needed flow.
- Should I move to an ASV machine right away?
RE: Flowgram looks like sonar pings - Deborah K. - 10-23-2024
To help you we need to see a full night's Oscar chart.
RE: Flowgram looks like sonar pings - bernardc - 10-23-2024
Deborah K.: Attached is the full graph. Please let me know what else you need. Thanks.
RE: Flowgram looks like sonar pings - Deborah K. - 10-23-2024
I am less familiar with Dreamstation, but it looks like your pressure settings need to be changed. You are hovering the whole time just below 13. I think you should try 11 to 16 for now instead of 9 to 13.
Your chart would be way easier to read if you set it up differently. We need to see the following items, and only the following, in the order listed on one page:
Event Flags
Flow Rate
Pressure
Leak Rate
Tidal Volume
Make sure we can read to the very bottom of the Tidal Volume.
As to ASV, let's see how you do first with the suggested changes
Try those new settings, post a chart, and tell us how you feel. Then we can see if additional changes would help. I think you will feel better.
RE: Flowgram looks like sonar pings - Jay51 - 10-23-2024
You shouldn't have any CA's with an AVAPS with a back up rate. I had the Evo ventilator (AVAPS) for a couple of years.
Your OSCAR mode shows S/T. Can you change this? I am wondering if you are in the spontaneous mode (back up rate disabled) and that is why you are having so many CA's.
Is there a way to set the back up rate manually? It could possibly be set really low as well.
Just some thoughts.
RE: Flowgram looks like sonar pings - Deborah K. - 10-23-2024
Clearly, Jay knows much more about your particular machine, so listen to him. I'm glad he showed up.
RE: Flowgram looks like sonar pings - bernardc - 10-23-2024
Deborah K.: Attached is the graph formatted as you instructed.
Jay51: S/T mode is described in the manual as "Spontaneous/Timed Pressure Support; A Bi-level therapy mode where each breath is patient-triggered and patient-cycled or machine-triggered and machine-cycled." This mode seems to simply start a 5-second timer (for the backup breathing rate of 12 bpm to which I've set my machine) at the start of inspiration, and upon timeout it initiates the next inspiration cycle. The timed (i.e. backup) breathing cycles are shown as TB event flags as well as ticks at the top of the flowrate graph. So yes, this is spontaneous mode with a 5-second backup. That's the only such mode on this machine because it is aimed at pulmonary needs as opposed to central apnea.
The shortcoming of this machine is that it has no pressure adaptation function, and thus my question about getting an ASV machine like a ResMed AirCurve 11 ASV. Is that what I need?
RE: Flowgram looks like sonar pings - Deborah K. - 10-23-2024
Much better, Bernard! Now get rid of the calendar and it will be perfect.
RE: Flowgram looks like sonar pings - bernardc - 10-23-2024
Deborah K.: Perfect graph attached. Thank you!
RE: Flowgram looks like sonar pings - bernardc - 10-23-2024
I see that the main feature of an AVAPS machine is that it can Assure the tidal Volume. I had this Feature disabled, but I think it might be good for central apnea. Here's what he manual says about it:
"2.2.1 AVAPS (BiPAP AVAPS device only)
If enabled, Average Volume Assured Pressure Support (AVAPS) is a feature available in the S, S/T, PC, and T modes. It helps patients maintain a tidal volume (VT) equal to or greater than the target tidal volume (Volume setting in the AVAPS) by automatically controlling the gradual change in pressure support (PS) provided to the patient. The rate of change is such that the patient is not aware of breath to breath pressure changes.
"The AVAPS feature adjusts PS by varying the IPAP level between the minimum (IPAP Min) and maximum (IPAP Max) settings to meet the prescribed assured tidal volume setting.
"As patient effort decreases, AVAPS automatically increases PS to maintain the target tidal volume. The IPAP or PS level will not rise above IPAP Max or PS Max, even if the target tidal volume is not reached. Conversely, as patient effort increases, AVAPS may reduce PS. IPAP will not fall below IPAP Min, even if the target tidal volume is exceeded. If IPAP Max is reached and the target tidal volume is not achieved, the Low Tidal Volume alarm activates if it is enabled."