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What the heck? Flow limitations and strange waveforms - Printable Version

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What the heck? Flow limitations and strange waveforms - DeepBreathing - 03-13-2020

Looking at my screenshot from Thursday night I'm seeing some very strange (for me) events. Huge amount of flow limitations, some hyperventilation around 04:00 and severely restricted flow at 04:35.

I'd appreciate comments and advice please.

[attachment=20974]    [attachment=20975]     [attachment=20976]


RE: What the heck? Flow limitations and strange waveforms - Sleeprider - 03-13-2020

You are getting double IPAP hits in a single cycle. I count 19 BPM but the machine is hitting you at 38 bpm with less than PS 4 during the event. Your respiration is responding, but you need longer, and greater IPAP PS to properly cycle Your machine has no settings to affect that. The easy answer is, if this is an isolated event, it's interesting and not much we can do about it. If you want to look into it more deeply, let's seet the tidal volume, resp rate and minute vent.


RE: What the heck? Flow limitations and strange waveforms - DeepBreathing - 03-13-2020

Thanks SR. I'll have to look back over previous nights to see if these are recurrent episodes.  Here are the other plots you asked for.

[attachment=20979]    [attachment=20980]   [attachment=20981]


RE: What the heck? Flow limitations and strange waveforms - DeepBreathing - 03-13-2020

I did find this interesting episode a few nights back - every second breath is severely truncated.

[attachment=20983]


... and this one, where it looks like the machine was almost in ventilator mode for about 45 minutes. Not the same problem as above but perhaps a bit worrying?

[attachment=20984]


RE: What the heck? Flow limitations and strange waveforms - Crimson Nape - 03-14-2020

It appears like your machine may be going on the "fritz". It looks too repeatable to be human. How many hours on it? It probably won't help, but have you tried a total power down reboot?


RE: What the heck? Flow limitations and strange waveforms - Sleeprider - 03-14-2020

it's interesting that at 04:30 on 3/12 your respiratory targets are relatively stable and very little pressure support is in play. In fact. in the whole night chart, it is a period of low pressure support and no flow spikes like we see 1/2 hour earlier. The screenshot of every other breath being flow limited shows a changing frequency of 12 BPM at 02:38 if we count all breaths, with 6 bpm for the larger breaths. In the next minute from 02:39, breaths are supported at a rate of only 6 bpm. The ventilator mode looks nearly perfect, but probably not what you want to see often.

I am purely speculating, but my opinion is pretty close to our favorite red neck. Your machine is losing sync with your respiration, and leaving you with a mix of pressure supported and less supported breaths or unsupported breaths. It is my understanding of the ASV that this is not expected behavior for the algorithm, and most chart I have observed, show relatively quick response, but pressure support is delivered in trends where PS will change over 3 or more breaths, not differently on every other breath. This looks more like Vauto delivery which follows the respiratory effort, rather than ASV where pressure support is delivered regardless of spontaneous effort to maintain the Mv target.


RE: What the heck? Flow limitations and strange waveforms - SarcasticDave94 - 03-14-2020

Definitely not patterns one would expect on an ASV machine. Those supposed half exhales to a half inhale look very odd, maybe a glitch or report error but I'm not certain. I can only add hope you get it figured out; not much help I can offer.


RE: What the heck? Flow limitations and strange waveforms - sheepless - 03-14-2020

regularity is also called periodicity. if one off, ignore. if it continues, consider some kind of physical spasm, like plm or similar. I'd expect a pattern like above if someone regularly elbowed or shoved you, for example. your sharp inhale, followed by relatively flow limited breaths could be your response to some kind of physical trigger, e.g., spasm. maybe even to environmental factors like noise. or reacting to a dream (although I'd wouldn't expect that to be so regular).


RE: What the heck? Flow limitations and strange waveforms - DeepBreathing - 03-14-2020

(03-14-2020, 07:31 AM)Crimson Nape Wrote: It appears like your machine may be going on the "fritz".  It looks too repeatable to be human.  

I don't wish to know that!

Quote: How many hours on it?  

Don't know - the counter was reset when Resmed installed a new motor in late 2018. They also repaired the humidifier at the same time. First use was in November 2013, so it's 6 and a bit years old. I'd hazard a guess that the machine has around 15,000 total hours.


Quote:It probably won't help, but have you tried a total power down reboot?

No, I was thinking this is a pulmonary problem, not a machine problem. But I have no shortage of breath or other expected symptoms.


RE: What the heck? Flow limitations and strange waveforms - Crimson Nape - 03-14-2020

Based on 7 to 8 hours of sleep since 2013 should but your little baby somewhere around 17900 to 20500 hours. I don't know if there are any deals in your neck of the woods, but I think I'd start keeping an eye out for another one.