(03-28-2014 12:20 PM)WakeUpTime Wrote:
(03-28-2014 09:24 AM)robysue Wrote: 2) It's worth considering what happens if you DECREASE the pressure settings just a smidge: What happens if you use IPAP = 11 and EPAP = 7?? The number of obstructive events (OAs and Hs) is likely to increase, but the number of CAs may go down. The question is what happens to the AHI? If the total AHI goes down enough with the pressure decrease, then trading a few more obstructive events for far fewer central events just might be worth it.
Last night, IPAP=11 EPAP=8, results were CA:8.5 / OA:1.7 / AHI:11.1.
Previous night, IPAP=12 EPAP=8, results were CA:14 / OA:2 / AHI:17.
Yes indeed, you're right of course that lowering the pressure actually improved the CAI results -- though it's still high and last night was a crummy sleep (as usual). Strangely, the CA events seem to cluster every hour, almost predictively.
Going UP in pressure is not going to reduce your total AHI because the obstructive part of your AHI (OAI + HI) is already pretty low and the centrals increase pretty dramatically is seems between IPAP = 11 and IPAP = 12.
Going DOWN in pressure may or may not reduce your total AHI because as the pressure(s) go down, the obstructive events (the OAs and Hs) may increase while the CAs should decrease. The question is which will change more? And can you find a set of pressure settings that brings the total AHI down below 5.0 and keeps it there?
Quote:Regarding setting EPAP at 4, I had the impression that EPAP settings really don't affect OAI and CAI that much (only IPAP); that it was more of a 'comfort thing' finding something that felt the most natural while not having too high of a PS that would cause an overly stressful transition between inhales and exhales.
Not quite: The EPAP has to be high enough to control the OAs and snoring. The IPAP has to be high enough to control the Hs, flow limitations, and RERAs.
The PS setting controls how far apart EPAP and IPAP can get from each other. The min PS setting is mainly comfort based, the max PS setting is a combination of comfort and whether the transition from EPAP to IPAP and back is "stressful." (More on this in a bit.)
This follows from what goes on during a typical BiPAP titration: The EPAP pressure is increased in response to OAs and snoring during a BiPAP titration. IPAP pressure is increased in response to Hs, flow limitations and RERAs, if the lab scores RERAs. There are also some guidelines about how far apart EPAP and IPAP should be allowed to range; if I recall correctly on a straight BiPAP titration, they like to keep PS= IPAP - EPAP between (3 or 4) on the low side and (6 or 7) on the high side. In other words, if IPAP - EPAP = (3 or 4) and EPAP needs to be increased, the tech will likely increase both IPAP and EPAP by the same amount. If IPAP - EPAP = (6 or 7) and IPAP needs to be increased, the tech will likely increase both IPAP and EPAP by the same amount.
(03-28-2014 09:24 AM)robysue Wrote: If so, it may be worth switching to BiPAP Auto mode. That may let you use less pressure on average, while still allowing the machine to increase the pressure as needed to treat the obstructive events. If you go this route, I'd suggest using max IPAP = 11.5 and min PS = 4 as starting "caps" since you already know that centrals are a problem when the pressure gets up around this level. The question is what should min EPAP be set at? That's a question that you might be able to get the doc to answer. But if you are really up to experimenting without the doc's official permission, you might try starting out at min EPAP = 4 (the minimum possible EPAP) and see if you're comfortable breathing with the pressure that low. Track what happens for a week or so, and then maybe see if there's some kind of correlation of pressure settings and when the CAs start to emerge. And also track just how much pressure the machine wants to use to keep the obstructive events under control. If your median IPAP = 11.0 or 11.5 and your median EPAP = 7.0 or 7.5, you'll know there's not much room for decreasing the pressures from the point of view of managing the obstructive part of your problem.
Wow, ok. That's sure is a specific suggestion -- better than I'd ever get from any of the 'certified professionals'. Yes, I have to make the adjustments on my own. Sleep dr. says leave it at 11.5, you're cured, goodbye. RT says seem to need an SV machine.
First note: The RT may be right: In the end you may need an ASV machine if you can't find some kind of a good compromise pressure level that is high enough to (mostly) control the OSA and low enough to (mostly) not trigger the CAs.
But, alas, the RT can't prescribe such a machine. Perhaps the RT could talk to the doc? That may or may not work however.
So in the meantime it may be worth taking things into your own hands and switching the machine to Auto BiPAP and seeing if you can experimentally find a good compromise pressure range to run your machine. In the end, if you can't, you're back where you are now: Trying to convince the doc that there's something wrong.
To give you some additional information about why I'm suggesting what I'm suggesting, it would help to understand how your machine will work if you change to Auto mode:
When you run a PR S1 BiPAP in Auto mode there are four or five settings that control the pressure levels in each breath:
- Start EPAP = the starting value for EPAP at the beginning of the ramp period. This value is only important IF you use the ramp. Note that Start EPAP < Min EPAP for the ramp to do anything. Also, if Min EPAP = 4, then you can't use the ramp and you won't have an option to change Start EPAP in the clinical menu.
- Min EPAP = the lowest value that EPAP can take on once the ramp period is over.
- Max IPAP = the highest value that IPAP can take on. In actual usage, you may or may not ever see IPAP reach Max IPAP.
- Min PS = the minimum distance between IPAP and EPAP.
- Max PS = the maximum distance between IPAP and EPAP.
In Auto mode, your System One BiPAP will respond to obsrurctive events
OSs, Hs, snoring, flow limtations and RERAs) by increasing EPAP or IPAP or both. The machine will increase EPAP for clusters of two or more OAs (or OAs+Hs) that happen within 5 minutes or so of each other and snoring. The BiPAP will increase IPAP for clusters of Hs, flow limitations, and RERAs. It will leave the pressure alone when it scores CAs.
Whenever min PS < IPAP - EPAP < max PS, the machine will increase EPAP and IPAP independently of each other.
When min PS = IPAP - EPAP, and EPAP needs to be increased, the machine will increase both the IPAP and the EPAP by the same amount.
When max PS = IPAP - EPAP, and IPAP needs to be increased, the machine will increase both the IPAP and the EPAP by the same amount.
Finally, it's worth noting that the Start IPAP pressure, the Min IPAP pressure, and the Max EPAP pressure are all determined by five pressure settings in the Clinical Menue:
Start IPAP = Start EPAP + min PS if you use the ramp.
Min IPAP = Min EPAP + min PS. This is the lowest IPAP pressure you'll see once the ramp is over.
Max EPAP = Max IPAP - min PS. This is the highest possible EPAP pressure.
So what I'm suggesting is that you allow the machine to titrate your pressure needs for the obstructive events in a rather narrow range so that the pressures do NOT get any higher than they already are (so as to minimize the number of CAs).
We know that a setting of IPAP = 12, EPAP = 8 controls the OAs and Hs quite well, but it also induces way too many centrals. What we don't know is whether there is a lower pressure that might control the OAs and Hs most of the time without inducing too many centrals.
I'm suggesting that you consider setting:
min EPAP = 4
max IPAP = 12 (or 11)
min PS = 4 (or 3)
max PS = ??? [As a starting "guess" you could just set max PS = 4 and force EPAP and IPAP to increase together. Or you could just set max PS = 8 (or 7) and allow the machine to increase EPAP and IPAP completely independent of each other.]
These proposed settings would allow your EPAP to range from a low of 4 cm to a high of 8cm. Your IPAP would range from a low of 8cm to a high of 12 (or 11) cm. The machine should be able to respond to the obstructive events in a timely enough fashion so that when you need pressures of 11/8 or 12/8 you get them, and that means you should not see a drastic increase in the number of OAs and Hs. (That's the whole point of an Auto)
And at the same time, your pressures might spend significant amounts of time below
your current settings, which could significantly reduce the number of centrals.
By looking carefully at the data recorded by the BiPAP for a couple of weeks, it may become clearer what pressure levels seem to start triggering the CAs and what pressure settings you really need to control the OAs and Hs. For example, it may become clear that as long as IPAP/EPAP is less than 10/7 (WILD GUESSES on my part) that CAs are not much of a problem. But too may OAs and Hs might happen if you used 10/7 full time.
With some careful tweaking you might find an Auto range that balances out the minimum pressure needed to control the OAs with the maximum pressure you can tolerate before CAs become a problem. But such tweaking will take time.
(03-28-2014 09:24 AM)robysue Wrote: 4) As for talking to the doctor. I've not had much luck here: I'm on Sleep Doc #4. Doc #1 fired me, Doc #2 and I fired each other at the same meeting, and I fired Doc #3. I get along with Doc #4, but part of that is that Doc #4 does use a patient portal system, and hence I can write emails which somehow provide for better communication in my case than the standard 5-15 minute face-to-face appointments ever did.
Wow again. There's so much demand for sleep experts that they are not providing the quality in-depth client care that is needed. If one doesn't push up the pressure considerably to improve their results and their service level, one will achieve sub-standard care filled with less than perfect implementations.
I'm eager to know, were all 4 doc's 'certified sleep dr specialists', or were some of them regular MD's, or ENT dr's or respiratory dr's? I'm asking because it's so difficult to find any medical professional that knows very much about sleep apnea.
Two are board certified in sleep and the other two are board eligible; three of the four are pretty much full time sleep docs who don't do anything else, and the fourth is a neurologist with a significant number of sleep patients. So they're not fly-by-nights just trying to trying to pad their pockets with an "easy to add" side practice in sleep medicine.
Notably, the only one who uses a CPAP is Sleep Doc #4, the only one who really "gets it" when it comes to understanding what it really takes to make this crazy therapy work in your own bed at night. And I think that's a large part of why we get along as patient/doctor.