Can anybody comment on this desaturation behaviour?

[desaturator]

Do heart arrhythmias affect pat?

The manufacturers say not, but they would, wouldn't they? All the studies that support this conclusion are funded by the manufacturer. In fact, all the studies the support the use of PAT at all are funded by the manufacturer. That isn't necessarily fatal to trusting them, but I think we need to be careful. In my case, my worry is that one of my other oddities was misreported at apnea.

I think I'm going to order another PAT test, from the same supplier, just so I have something I can compare directly with my pre-CPAP measurements. I've also bought an IR security camera so I can check whether any of my oddities is related to sleep position.

BW, DS

[Geer1]

I haven't read their studies in detail but from what I did see I believe they were mostly just proving that they are fairly accurate against PSG in the average population. I may be wrong but I don't believe they have investigated all the possible things that their equipment may mistakenly label AHI or RDI (doesn't make sense for them to spend money on doing so either).

If it is free/cheap another PAT test on CPAP would be somewhat interesting and we could confirm and compare AHI (less so RDI) using OSCAR data. If nothing else it may help understand the accuracy of initial test.

[Brucpap]

@Geer1: another reasonable night for SpO2. Average was 97%, and just a few seconds below 90%. AHI was 0.8. All the (5) events marked by the machine were clearly aligned with flow limitations, so I guess probably obstructive. Periodic breathing was still present, but probably not as much as yesterday. In fact, I think my breathing is always periodic if I look carefully enough. Perhaps everybody's is? It's just that sometimes the periods are clearly visible, and sometimes they aren't.

Incidentally, now I know what that period breathing looks like in my SpO2 graph, I can see it even in recordings where I wasn't using the CPAP machine at all. I've attached a sample from a night without CPAP. At least some of the fluctuations in SpO2 have the same cycle length as the ones I see on CPAP. Of course, without the CPAP, there could be all sorts of other stuff going on that I can't see. For better or worse, I don't have any overnight recordings from before I started using CPAP (except my sleep study, which isn't detailed enough). So, while I know the periodic breathing is present when I stop using CPAP, I don't know if it was there before I started.

What seems odd to me is that the desaturations are so huge. Sometimes SpO2 can drop ten percentage points in ten seconds. I can't reproduce that behaviour simply by not breathing. In fact, no breath-holding I've tried has ever reduced my SpO2 by more than one percentage point. So how can it drop so quickly at night? I guess my cardiac output is lower, but is it that much lower?

As you know, I'm doing this CPAP thing because my doctors say that low oxygen saturation may be the cause of my night-time arrhythmias. My overall SpO2 is now OK, I think; but I have no idea what effect repeated, sudden desaturations by ten percentage points will have. Nor do my doctors; in fact, they tell me that they've never seen anything like this before in a generally well person with normal heart and lung function. So it's baffling.

Best wishes, DS

Any update? I seem to be having the same issue. My SPO2 fluctuates like crazy with or without CPAP.