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+--- Thread: Flowgram looks like sonar pings (/Thread-Flowgram-looks-like-sonar-pings)
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RE: Flowgram looks like sonar pings - Jay51 - 10-23-2024
Thank you for posting all of that information. You can try AVAPS and see how you like it (and compare OSCAR charts). If you set it to the T - timed mode, it should initiate a breath every 5 seconds (with a 12 second back up rate).
If CA's still occur in AVAPS or T (timed mode), then your pressure support (IPAP max) is too low to trigger a breath).
The OSA part is much easier to attempt to fix with pressure changes if that is still a problem as well. If you get more OA's, then raise the EPAP. If still getting CA's, then raise pressure support (IPAP). *Positional apnea could be affecting your sleep as well if you see "clustes" of OA's on your OSCAR charts.
I don't mean to give too many suggestions at once. Tweaking one thing and looking at OSCAR is the best way to go.
RE: Flowgram looks like sonar pings - bernardc - 10-23-2024
Jay51: Here's the problem I see with T mode, to quote the manual:
"Timed Pressure Support; A Bi-level therapy mode where breaths are machine-triggered and machine-cycled. T mode provides mandatory pressure assist with bi-level pressures. The patient’s breathing rate has no effect on the machine rate or pressure levels. The trigger to IPAP is determined by the breath rate setting, and the cycle time is determined by the Inspiratory Time setting."
In other words, it's an external ventilator that doesn't respond to the patient. And in the case of the AVAPS feature being turned off, it just applies the pressures for fixed times. This combination could be called Brain Dead mode. I'm going to try turning on the AVAPS feature with a tidal volume of 550 mL and an upper pressure limit of 25 cm w.c.
But what about these sonar pings. I've attached a zoomed-in view. What to make of this?
Another question: Tidal volume must be highly smoothed, as it must be an integral of the square root of the pressure minus the leak rate, assuming a turbulent Reynolds Number. Is it reported by the machine? Or calculated in Oscar?
RE: Flowgram looks like sonar pings - Jay51 - 10-24-2024
Great job looking up that pertinent information. It took me some time to get used to a preprogrammed, set back up rate. I eventually did though. Once you know your average respiratory rate during the night (from OSCAR, or a sleep study, or I had some CapOx tests that showed mine was either 12 or 13). Yours may be a bit higher than this. Then simply set the back up rate to either that number or slightly lower by a few breaths (so that you breathe normally the vast majority of the time; but if you ever need it, the back up rate will kick in for you (most likely during REM sleep).
550 is a good choice for tidal volume. I am 6'2 and my Pulmonologist recommended 500 for me. You can tweak that up or down a little bit based on your OSCAR charts and comfort as well.
I really hated the EVO ventilator when I first got it. That changed 180 degrees after using it awhile. Machines like these have many different settings. It takes some time to get all of the settings "just right". But when everything is set correctly, it can be very good therapy IMO.
I am not 100% sure what the "sonar pings" are. You might benefit from positional apnea techniques as well: OSCAR gives a median tidal volume and 95% (best for flow limitations reporting) min, and max, etc. I really only use the median number myself personally for tidal volume. It would be great to keep tidal volume smooth and steady all night. I have found using AVAPS "smooths" out my tidal volume better.
RE: Flowgram looks like sonar pings - bernardc - 10-24-2024
Attached is last night's data--overall and a detailed sample--in which I turned on the AVAPS feature which applies more pressure until the minimum tidal volume is achieved. This largely eliminated the sonar pings. But I'd really like to know what you experts think. I'm all ears.
And here's an Oscar question: Is there a way to drag the time left and right? This is called scrubbing in video editing. I know about clicking to the right and left of the events window to move it, but dragging is sometimes preferable.
Also, is there a way to highlight and measure selected time periods without altering the time scale? Attached is an illustrated example.
RE: Flowgram looks like sonar pings - Jay51 - 10-24-2024
As far as AVAPS goes, your charts looks better than other charts you have posted IMO. You still have significant H's. You could try raising EPAP a little bit, increasing IPAP a little bit, or even trying some positional apnea techniques since a few of your H's are clustered. Lowering pillow height, side sleeping instead of back sleeping, and possibly trying a soft cervical collar.
I am not sure how to do all of the editing to OSCAR that you ask.
RE: Flowgram looks like sonar pings - bernardc - 10-24-2024
Jay51: A sonar ping is a waveform in which the amplitude jumps up from zero and decays down to zero again before the next one starts. It's similar to ringing a church bell. My breathing without AVAPS has sudden starts that decay down to nothing. With AVAPS, they decay down to triggering timed breathing. Attached is a marked up example.
RE: Flowgram looks like sonar pings - Jay51 - 10-24-2024
Thank you for explaining that bernardc. I now understand what you are talking about. That is strange. It kind of resembles Cheyne-Stokes breathing pattern (you can look it up), but only half of it. There is both a crescendo and decrescendo in CSR (but they are symmetrical).
One thing I do see with your waves is big time flow limitations. Very pointed tops on some waves; and flat 2 peaks on others. Normal wave tops should be round (like a half circle).
From what I have learned about AVAPS, this should not be occurring. Every breath should about the same height due to the "assured volume" feature that assures every breath will be at least "x" tidal volume. I am not sure how to correct this if you are in AVAPS mode and your tidal volume it set at 550.