College3girls,
Here's what I notice in the data you've posted:
Even on the good nights, there seem to be some thick clusters of events associated with some extremely steep rises in pressure. Most of the events are scored as OAs, but in the longest, most persistent clusters on the bad nights, there are a fair number of CAs mixed in with the OAs once the pressures are above IPAP = 21; EPAP = 17 (I'll use IPAP/EPAP in the rest of this post.) It's almost as if once the pressure gets above 21/17 your mom's breathing is at risk of becoming highly unstable. It doesn't happen every time the pressure gets that high, but it when it does, your mom has a doozy of a cluster that can last for 30 minutes to an hour or more. The two clusters on the night of June 1 are examples of what I mean. The thirty minute cluster towards the end of the night on June 3 is another example. But the really bad example is that two hour cluster on June 4.
Another thing that stands out in your mom's data: At the start of the worst of her clusters, there is always a sharp rise of as much as 6 cm in pressure in a relatively short period of time. For example, at the beginning of that nasty cluster on June 2, there's a total pressure increase of 8.5 cm, and that increase includes a vertical rise in pressure of about 6.5 cm that takes place in maybe 3-4 minutes right at the beginning of the cluster. Maybe that sharp pressure increase causes her to blow off too much CO2, which can then trigger a cycle of alternating hypoventilation and hyperventiation. Or perhaps that sharp rise in pressure is simply causing your mom to arouse and move around and then she winds up on her back and that's what keeps the cluster going for so long.
You'll notice that during the times when the pressure is highest (above 21/17), the respiratory rate is also jumping all over the place. Is her minute ventilation and tidal volume also jumping all over during the really bad clusters? It would be really useful to see a zoomed in version of some of these clusters of events. And by zoomed in, I mean zoomed in far enough to see the individual breaths more clearly.
And when these clusters occur, the timing of the
beginning of the events still looks to me like they're likely starting in REM sleep, but for some reason they're persisting long after a REM cycle ought to be over. One possible explanation is that the really sharp increase in pressure over a very short period of time is what's causing the destabilization in your mom's breathing. Maybe that sharp pressure increase causes her to blow off too much CO2, which can then trigger a cycle of alternating hypoventilation and hyperventiation, and it's a CO2 undershoot/overshoot cycle that continues to feed the cluster for a very long time once it starts.
So here's what I'd be inclined to think about this were my data:
1) I'd start by bumping the min EPAP up. It looks like your mom's current min EPAP = 11 and PS = 4, so her min pressures (after the ramp goes off) are 15/11. And that's just not high enough to prevent the nasty clusters from getting started in the first place. Except for the best night, her median EPAP is running around 13.5-14.5 cm and her 95% EPAP is a lot higher. So she probably needs at least 2 cm more of EPAP pressure, but making a 2cm jump in min EPAP is a pretty big change. I'd start by bumping min EPAP up to 12 and leave it there for 4-7 days gathering more data. If the data is still all over the place, I'd bump EPAP up to 13 and leave it there for 4-7 days gathering more data.
2) But at the same time, I really think there's something strange going on when your mom is dealing with pressures above 21/17. I'm still worried that some of those OAs scored during the longest clusters when the pressure is at or above 21/17 for 30 minutes or more might just be mis-scored central events. Certainly in the longest of these types of clusters, there's a large number of CAs mixed in with the OAs. And so I'm wondering if your mom's CO2 levels start to go a bit crazy once the pressure gets that high. So I would lower the max IPAP down quite a bit from the current max IPAP = 25. How far to lower it? Well, that nasty cluster on June 4 really gets going when the pressure is above 23/19, but it keeps going even after the pressure dips as low as 22/18. Personally, I'd try lowering the max IPAP all the way down to 21 for a few days and seeing if the "high pressure clusters" get better or worse. If you see real improvement in the number and length of the "high pressure clusters", then you'll know that your mom is sensitive to extremely high pressure, and that the max IPAP does need to be set below the default of 25 cm. On the other hand, if the "high pressure clusters" get worse, then you'll know that those clusters probably ARE mainly obstructive and your mom needs the higher pressure (and probably needs an even higher EPAP in the long run.)
3) By raising the min EPAP and lowering the max IPAP at the same time, this may also reduce the tendency of your mom's VPAP to increase the pressures quite drastically over a very short period of time. And that in turn may also help stabilize her breathing pattern.
So here's what I'd propose as an idea to try for the next week or so:
- Increase min EPAP to 13
- Decrease max IPAP to 21
- Keep PS = 4
- Keep the ramp settings the same
These settings will allow EPAP to range from 13 up to 17 and IPAP to range from 17 up to 21. Even though the max pressure allowed will be less than the current settings, the higher min EPAP will do two things: It will make it a bit harder for a nasty cluster to start in the first place and once a cluster does start, the machine won't have to increase the pressure quite so far to get to the needed pressure.
And capping the IPAP and limiting the maximum pressure increase to a total of 4cm should help give your mom's breathing a chance to stabilize after a more modest pressure increase once a REM-induce cluster of events does occur. And capping the pressures at 21/17 may help prevent the super long clusters from happening if they are the result of unstable breathing due to some kind of a CO2 overshoot/undershoot problem that develops when when the pressures stay above 21/17 for long periods of time.
