ResMed BiPAP "out of sync" with a gap in pressure data

Hi y'all!

A ton of thanks to everyone who gave advice on my father's condition (viewtopic.php?t=188474). He's continuing to use BiPAP to improve his sleep. I now have another specific question:

My father said that last night there was a period at the beginning where he felt the BiPAP was weird, a bit "out of sync". When I looked at the data from last night, I saw a brief gap where the pressure data was entirely missing. I suppose this corresponds to the period he complained about. There is a "large leak" event around the same time, but it didn't last very long according to the data, and my father said he couldn't recall hearing air blowing out of the mask.

Here's the data on SleepHQ: https://sleephq.com/public/44e854bd-d7c ... a6aa6423cb

What could be the cause of this? What can he do to prevent this?

Thanks!!

forohfor wrote: ↑

Sat Jul 13, 2024 4:36 am

What could be the cause of this? What can he do to prevent this?

I don't know what caused it. Maybe others have some ideas.

It's only five minutes. When something like this happens, I just assume it's a one-off. If it happens more times, some serious investigation would be needed.

SHQ recorded two 'sessions'... but the Ramp feature kept going during the missing period... the machine was definitely not 'off'.

The breaths look pretty feeble before the break... then they pick up after. Perhaps S/T mode kicked in and SHQ doesn't know how to process that?

On my Aircurve the machine has to learn where I'm breathing to sync up... but this happens within a few breaths.

I've seen SHQ uploads get corrupted... i.e. a difference between Oscar and SHQ. As CG said, if it's a one-off no worries... watch for it again. Is he alone when he puts on the mask and starts the machine?

vandownbytheriver wrote: ↑

Sat Jul 13, 2024 7:13 am

SHQ recorded two 'sessions'... but the Ramp feature kept going during the missing period... the machine was definitely not 'off'.

The breaths look pretty feeble before the break... then they pick up after. Perhaps S/T mode kicked in and SHQ doesn't know how to process that?

On my Aircurve the machine has to learn where I'm breathing to sync up... but this happens within a few breaths.

I've seen SHQ uploads get corrupted... i.e. a difference between Oscar and SHQ. As CG said, if it's a one-off no worries... watch for it again. Is he alone when he puts on the mask and starts the machine?

It doesn't seem to be a SHQ thing, at least Oscar shows the same pattern (attached).

He was alone when he put on the mask, unfortunately I'm no longer with my parents and I'm just tele-debugging this issue for him.

You're definitely right that the breath seems feeble before the gap, in fact when I zoom into the flow rate graph it looks very weird (also attached). The more normal pattern is a wave the goes between -20 and +20. My father was definitely awake during that period so it's very unlikely that he actually breathed this little. More like the machine was failing to detect his breathing for some reason? There's a leak within that period, but (1) it doesn't cover the entire period and (2) there were several other leaks of similar magnitude later in the night.

What puzzles me the most is why the data would be entirely missing, even in S/T mode I guess I should still expect to see some data? The machine definitely wasn't off as the ramp-up was still in progress.

forohfor wrote: ↑

Sat Jul 13, 2024 7:55 am

...More like the machine was failing to detect his breathing for some reason? There's a leak within that period, but (1) it doesn't cover the entire period and (2) there were several other leaks of similar magnitude later in the night.

I know that some functions on RM machines are disabled during Ramp. That doesn't explain the blank spot in the data (not an upload problem as shown by Oscar).

What puzzles me the most is why the data would be entirely missing, even in S/T mode I guess I should still expect to see some data? The machine definitely wasn't off as the ramp-up was still in progress.

You'd expect S/T (Spontaneous/Timed) to kick in a little pressure when low breathing was detected... but I'm not familiar with the algorithm etc. In fact the pressure is flat all night. Aside from checking all electrical connections and watching for a second occurrence I have no clue. You monitor his graphs and this is not normal, obviously.

I think I figured it out!

My father's breathing was indeed slower than usual, in particular inspiration took longer than Ti max (set to the machine's default of 2.0s). SleepHQ doesn't really have that graph, but Oscar does show that data.

So the reason he felt it was out of sync was that the IPAP switched over to EPAP while he was still breathing out. Maybe at one point S/T mode kicked in, as you can see his respiratory rate was indeed dropping below the backup rate of 10.

Still not sure about why there's a gap. My suspicion is that either the machine stops recording the data at S/T mode, or the data format during S/T mode is something Oscar doesn't support?