How do I adjust pressures to balance CA's and FL's?

I have narrowed the gap of my pressure settings to a workable arrangement, so my question pertains more to learning about the principles of IPAP/EPAP settings. In general, my OA's are under control (frequently 0), so my main issues are with CA's and FL's. When pressures rise due to FL's, then I experience CA's. This sometimes happens during the hunt-and-peck phase of the machine. Is this what I have to live with? AHI's are usually 2-3 range, never going above 7.5.

M'ohms wrote:In general, my OA's are under control (frequently 0), so my main issues are with CA's and FL's. When pressures rise due to FL's, then I experience CA's. This sometimes happens during the hunt-and-peck phase of the machine. Is this what I have to live with? AHI's are usually 2-3 range, never going above 7.5.

What's your max IPAP set to?

Since the CAs seem to correspond to the FL-induced pressure increases, setting a reasonable max IPAP is probably the answer. That will likely increase the number of FLs, but if I were you, I'd consider tolerating a fair number of FLs in exchange for lowering the number of CAs.

M'ohms wrote:I have narrowed the gap of my pressure settings to a workable arrangement, so my question pertains more to learning about the principles of IPAP/EPAP settings. In general, my OA's are under control (frequently 0), so my main issues are with CA's and FL's. When pressures rise due to FL's, then I experience CA's. This sometimes happens during the hunt-and-peck phase of the machine. Is this what I have to live with? AHI's are usually 2-3 range, never going above 7.5.

I would recommend trying straight pressures........fixed EPAP and IPAP and see how that works. You should be able to tell from your reports what some reasonable starting pressures should be. From what I've read, Central Apneas are more prevalent above the pressure of 10 cm., so your pressures are above that. If you've eliminated the Obstructive Apneas, you may be able to dial back your pressures to find the optimal ones for fewer Centrals.
Depending on how many you're experiencing, maybe you should discuss an ASV machine with your doctor.


Den

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I had max IPAP set to 19, but had a bunch of FL's. I raised the max to 20, which helps the FL's, but of course, I have a bunch of CA's. My events cluster around REM events, so I have not had much success with straight pressures. If I set the pressures to combat the REM clusters, then I have aerophagia pretty bad. Lowering the pressure helps with the aerophagia, but not with the AHI clusters.

Re: How do I adjust pressures to balance CA's and FL's?

M'ohms wrote:I have narrowed the gap of my pressure settings to a workable arrangement, so my question pertains more to learning about the principles of IPAP/EPAP settings. In general, my OA's are under control (frequently 0), so my main issues are with CA's and FL's. When pressures rise due to FL's, then I experience CA's. This sometimes happens during the hunt-and-peck phase of the machine. Is this what I have to live with? AHI's are usually 2-3 range, never going above 7.5.

I know what you are saying, but I don't think CA's and FL's, as reported by a home machine, are generally considered things to be "balanced." Finding a set of stable pressures, as Wulfman suggests, may prevent the issue and is a worthy endeavor. But if things are that touchy, that may mean, as Wulfman also points out, that it is time to look into ASV. That makes more sense to me than choosing one or the other to give priority to, between FL's and CA's. Here is why I feel that way.

It is true that sometimes the higher pressures needed to stabilize the airway can trigger centrals. However, discerning the true nature of a FL from a flow curve is not an easy thing for a home machine to do. So taking for granted that those home-machine-reported FL's are all 100% obsturctive in nature (as in simple narrowing) is not something I would be comfortable assuming as a patient based on home-machine data alone. The reported FL's could be just as central as the reported CA's. And if that is the case, increasing the pressure may not be so much treating obstructive FL's as it is turning minor central events (gettting reported as FL's) into larger ones (getting reported as open-airway apneas). It would be difficult to tell one way or the other from home-machine data. But in my opinion, that possibility is something to keep in mind while dial-wingin'.

Autobilevel can be great for comfortably stabilizing an airway against obstructive events. But if there are continued central troubles that are disturbing sleep or that are otherwise disruptive, fiddling with pressures on the autobilevel isn't really going to treat that, even if it appears to change the home-machine-reported numbers in a favorable way.

It is my personal opinion that either the home-machine-reported open-airway events are of the sort that should be ignored or they are of the sort that should be addressed with a machine that can prevent them, an ASV. A doc would be in the best position to decide such things. But we as patients trying to figure out whether it is in our best interests to chase the home-machine reported FL's or the home-machine-reported CA's could easily get caught up chasing ghosts without enough information to know exactly what we are doing and why.

I believe that an unstable airway is one sort of problem. But I believe that an unstable pattern of breathing that is central in nature is another sort of maybe-problem-maybe-not-problem completely. Sometimes the treatment of one problem brings another one to the surface, and sometimes treating the obstruction helps the central problems go away in time, and sometimes the two problems are closely related in other ways, but they are still two different problems, really. When both problems manifest during CPAP or BPAP and remain so for some length of time, it may be best to start making a case for ASV. If the breathing feedback loop is that sensitive and remains so over time after apneas and hypopneas are controlled, hiding the problem temporarily may not be in the patient's best interests when ASV can smooth everything out in the long run, as in, for years and years to come.

In my opinion.

I just saw a post by -SWS in another thread, though. So hopefully he can weigh in and correct anything I may have misstated or worded badly above.

Thanks for the thoughtful reply. You have given me some new things to think about. I always considered a FL to be a pre-cursor to an obstructive event, but it makes sense that it could also lead to a CA event. I may try lowering my IPAP a little or even try straight mode to see how that works. I do think I have breathing instability and have a lot of fragmented sleep (I consider sleeping 2 straight hours a blessing). Maybe a new discussion with my sleep doc is in order.

M'ohms wrote:I had max IPAP set to 19, but had a bunch of FL's. I raised the max to 20, which helps the FL's, but of course, I have a bunch of CA's. My events cluster around REM events, so I have not had much success with straight pressures. If I set the pressures to combat the REM clusters, then I have aerophagia pretty bad. Lowering the pressure helps with the aerophagia, but not with the AHI clusters.

and

M'ohms wrote:AHI's are usually 2-3 range, never going above 7.5.

M'ohms,

What do the FLs and CAs numbers look like when your max IPAP = 19? And how would you rate the overall quality of your sleep is when your IPAP = 19?

If the CAs mostly disappear, the AHI < 5 all the time, and the aerophagia is bearable when max IPAP = 19, then max IPAP = 19 is probably the way to go, even if it does mean an uptick in the number of FL scored by the machine.

My two cents on a number of things:

1) Balancing out aerophagia and the event clusters is extremely important. If using the BiPAP in Auto keeps the aerophagia at manageable levels and keeps the OSA under control, then I don't think there's much to be gained by using fixed IPAP/EPAP pressures.

2) Should you decide to experiment with fixed IPAP/EPAP, be aware that the PR System One will no longer record FL, and so your FLI = 0.0 on any night you use the machine in fixe pressure mode. That doesn't mean the FL have been eliminated; it's just that the machine is not flagging them. That's just the way the machine was programmed. It's a stupid decision on PR's part in my opinion, but there's nothing we as users can do about that.

3) With an overall AHI that is usually in the 2-3 range and occasionally getting as high as 7.5, I personally think it is way, way too premature to be talking about ASV machines. The usual criteria to get switched to an ASV are all of the following:

• a treated AHI that is consistently above 5 at pressures needed to control the obstructive events;
• a CAI that is consistently above 5 while on CPAP/APAP or regualar BiPAP;
• and CAs make up at least 50% of the events

It does not sound like your problem with CAs is that severe. And that's why I think talking about ASV machines is premature at this point.