Can anybody comment on this desaturation behaviour?

[Geer1]

That is kind of weird and interesting how you say the periodic breathing if anything looked worse but that you O2 levels were the best they have been.

You can never draw conclusions off a single night so I would run with those settings a few more nights and see if it makes any more sense. You are looking for any correlations between periodic breathing, apnea and spo2. Specifically with the periodic breathing perhaps although it occurred more it was in lower amplitude causing less change in the spo2?

[desaturator]

Specifically with the periodic breathing perhaps although it occurred more it was in lower amplitude causing less change in the spo2?

Maybe. But I think it was more that my SpO2 was higher outside the period breathing episodes. So those episodes did not trash my SpO2 so badly. But, as you say, it's difficult to generalize from one night. Will try again tonight.

BW, DS

[Geer1]

Yeah I want to see a few nights averaged out and compared to previous example. SPO2 improving with EPR being reduced is the opposite effect and would support that a central apnea aspect (maybe as simple as slower respiration rate?) is present. This could all be theory based on an odd night of data though so multiple nights is key.

[desaturator]

@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

[desaturator]

And another thing...

I've been looking into the tendency for CSA to cause, or at least exacerbate, OSA. I raised a separate thread on that topic. But, if this is true, it would explain a lot about my own problems. I've so far assumed that the periodic breathing I have is actually being stimulated by obstruction, but how likely would it be that the "obstruction" always has the same periodicity? See the attached -- do obstructive flow limitations normally follow a regular pattern like this?

I'm wondering if my problem could be primarily central, rather than obstructive, although that isn't the way ResMed sees it.

Best wishes, DS

[Sleeprider]

This is an interesting view of periodic breathing where the hypopnea are apparently obstructive inspiratory flow limitation, followed by hypercritical hyperventilation. With the clustering, this may have a positional aspect.

[desaturator]

With the clustering, this may have a positional aspect.

Is positional apnea associated with regular episodes of flow limitations like this? What struck me is the uniformity of the pattern. Sometimes I have episodes of periodic breathing that aren't associated with flow limitation (at least, none that registers), with essentially the same period as when I do see flow limitations (see attached).

I am happier with the idea that flow restrictions are causing the periodic breathing than the other way around. However, the fact that I have period breathing of the same period when no flow restrictions make me worry that it might be the other way around.

BW, DS

[Sleeprider]

Your close-up in this most recent image is more classic periodic breathing and does not exhibit flow limitation, nor is it flagged or graphed. This resembles classic central closed loop hyper/hypo-capnia. The first image showed strong association of flow limits with the hypopnea. When we see clusters of obstructive activity, positional issues are often suspected. It is often chin-tucking followed by arousal and normal breaths, and a repeating cycle. This wiki covers it in the flow limitation with obstructive apnea section http://www.apneaboard.com/wiki/index.php...limitation

[Geer1]

Positional apnea as forums like this have labelled it usually shows up as full blown repetitive obstructive apnea but if the position aspect only causes a partial obstruction it can cause repetitive flow limitations like this instead. I have seen this in my own data at times and when I caught it on camera it was a night where I shifted position in sleep and head was on front edge tilting head forward and kinking airway.

As sleeprider somewhat mentioned some of your data shows a potential obstructive positional apnea feature whereas some shows a more typical central or periodic breathing nature. As you noticed you appear to have a periodic breathing nature even when not on CPAP which might explain why your periodic breathing doesn't appear to be modified when adjusting EPR (like one would expect if the periodic breathing was caused by TECSA).

Your case is definitely a unique one being heart driven. I can't help but think they must be able to test and prove that CPAP is helping you by doing say a multi day holter monitor test where you sleep one night with CPAP and one night without to see the effects CPAP is having on heart function. Since the treatment is only targeted towards cardiac symptoms I think it warrants a doctor proving the treatment is working rather than assuming your arrhythmias are caused by the apnea that don't appear to be causing other symptoms.

[desaturator]

@Sleeprider, @Geer1

Thank you. The original plan was always to see if CPAP stabilized my oxygenation and, if it did, to repeat the holter monitoring for another week.

On the one hand, there's no doubt that the CPAP has some effect on my oxygenation, compared with before. In the original sleep study, my average SpO2 was 90%, with 117 desaturations 4% or more during the night. On CPAP, my average SpO2 varies between 94% and 98%, and my >4% desaturations are 1 to 26.

On the other hand, on CPAP I still experience periodic breathing that seems to be both flow-related and in clear airways. I still have hundreds of smaller desaturations every night. My SpO2 is by no means even approximately constant.

Worse, none of this seems to be affected much by any settings change I make on the CPAP machine. Actually, even worse: changing settings improves some things while worsening others. For example, reducing EPR increases my average SpO2 by about 1 percentage point, but increases the number of >4% desaturations I have. I don't have many of these on CPAP, whatever the settings, but they all occur within a short time of one another, so they could still be relevant.

So, while the CPAP probably is improving my oxygenation to some extent, I think it's still a long way from normal. It's also possible, though, that the CPAP has some other cardiological benefit, beyond just oxygenation.

I don't really see any alternative to repeating the holter test but, since I'm paying for all this out of my own pocket, and it's ruinously expensive, the idea doesn't fill me with enthusiasm. I would be happier to fund the further testing if I knew I had arrived at the "best possible" CPAP settings, but even that I can't be sure of.

I'd welcome any other suggestions because, to be honest, I don't really have a clue at this point.

BW, DS