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Couple of questions about APAP - kderevan - 06-05-2014

Only two nights in, and the APAP is definitely working better for me than the CPAP. I do have a couple of questions based on the numbers I see:

The DME guy said he was going to set my pressure from 10-20 (based on my prescribed pressure of 11) but I think he may not have done it, since my reported pressure ranges from 8 to 19.5. It's working for me, so that's not an issue, I'm just wondering what is the downside to leaving the APAP "wide open" at the original settings of 4-20 (as I've read here)? Is it only a problem if the varying pressures are uncomfortable to the patient, or is there something else? I seem to be very tolerant, because even on my sleep study night I didn't find the mask or air pressure uncomfortable, and I quickly reduced my ramp time when I got the equipment at home.

And the other isn't really a question exactly, but I know that many people (doctors and patients) say that CPAP is still the best way to go instead of APAP and I wonder why. It seems like having the pressure continuously adjusted in response to the patient's breathing is ideal.

Oh, there is one more thing. My mouth was dry when I woke up, so I think that at the highest pressure I'm doing some mouth breathing even with the chin strap, getting some leakage out the mouth. Is it safe to assume that I might get a bit more mouth leakage with the higher pressure? and that as long as my apneas are being controlled, I just won't worry about a little more mouth leakage?

I am still very new to this, so there is a LOT I don't know! All I do know is that I'm happy to finally have treatment for apnea (after YEARS of suffering) and I regret not getting treated sooner.


RE: Couple of questions about APAP - WakeUpTime - 06-05-2014

(06-05-2014, 12:02 PM)kderevan Wrote: And the other isn't really a question exactly, but I know that many people (doctors and patients) say that CPAP is still the best way to go instead of APAP and I wonder why. It seems like having the pressure continuously adjusted in response to the patient's breathing is ideal.

Oh, there is one more thing. My mouth was dry when I woke up, so I think that at the highest pressure I'm doing some mouth breathing even with the chin strap, getting some leakage out the mouth. Is it safe to assume that I might get a bit more mouth leakage with the higher pressure? and that as long as my apneas are being controlled, I just won't worry about a little more mouth leakage?

Speaking personally, my body hates varying pressures. I find A-mode great for analyzing the pressures afterwards and then making adjustments for the days ahead. My mask hates A-mode too as sudden increases in pressures cause middle of the night leaks for me.

It makes sense I suppose, as there's a perfect pressure for everybody to keep that back area muscle from collapsing. However, in A-mode, I found some nights that it would be always settling around 11, and other nights where it likes 15. Perhaps that's another benefit of A-mode is that the perfect pressure is 'perfect' for that night only. With so many other factors in good sleep (foods, alcohol, exercise, etc. etc.), I found that that 'perfect pressure point' definitely isn't perfect each night. My machine needs a label "SUBJECT TO CHANGE WITHOUT NOTICE", and I suppose that's what A-mode is all about. I suppose the 'seasoned experts' on the board might tell you to narrow that range over time as too large of a range can be problematic.

I wish I could help you on the mouth leaks. I suffer from that too. Between the mask leaks and mouth leaks, it's a challenge for sure. I'm now thinking about tape (or something equivalent).

Many others on the board have years of experience instead of my months -- and they've been a lot more successful. Hang in there for their tremendous responses coming up.



RE: Couple of questions about APAP - robysue - 06-05-2014

(06-05-2014, 12:02 PM)kderevan Wrote: The DME guy said he was going to set my pressure from 10-20 (based on my prescribed pressure of 11) but I think he may not have done it, since my reported pressure ranges from 8 to 19.5.
Are you getting this off of SleepyHead? Or are you using ResScan? It makes a difference.

And are you using the ramp? If so, what's the beginning ramp pressure set to?

And are you using EPR? If so what's it set to?

I'm asking because the most likely explanation is that you are using the ramp with a starting ramp pressure of 8 and looking at the data in SleepyHead.

It would help to see a screen shot of the detailed data with all the graphs rather than the summary data.

Quote:It's working for me, so that's not an issue, I'm just wondering what is the downside to leaving the APAP "wide open" at the original settings of 4-20 (as I've read here)? Is it only a problem if the varying pressures are uncomfortable to the patient, or is there something else? I seem to be very tolerant, because even on my sleep study night I didn't find the mask or air pressure uncomfortable, and I quickly reduced my ramp time when I got the equipment at home.
The biggest problem in leaving the pressure wide open at 4-20 is that it takes the machine time to respond to events. And whenever your breathing is stable, the machine's going to try to decrease the pressure all the way back down to 4cm. And if you need a pressure level that is substantially greater than 4 cm, that means that you're at a subtherapeutic pressure for long periods during the night. And that allows too many events to occur. So your therapy is not particularly well optimized.

Since your titrated pressure was 11 and the AutoSet is sometimes increasing the pressure all the way to 19.5, if you lowered the min pressure to 4, then you would likely see a pretty significant increase in AHI and the increased AHI would likely cause you to feel much worse than you are right now.

And then there's a comfort issue as well: For someone like you who has no problems tolerating pressures of 8-19.5, you would probably find starting at 4cm to be very uncomfortable---you would notice that there's no where near as much air coming in through the mask at 4cm as there is at 8cm. And that can lead some people to feel as though they're suffocating from lack of air at 4-6cm.

Quote:And the other isn't really a question exactly, but I know that many people (doctors and patients) say that CPAP is still the best way to go instead of APAP and I wonder why. It seems like having the pressure continuously adjusted in response to the patient's breathing is ideal.
It' a complex issue. And some people do better on fixed CPAP than on APAP.

Quote:Oh, there is one more thing. My mouth was dry when I woke up, so I think that at the highest pressure I'm doing some mouth breathing even with the chin strap, getting some leakage out the mouth. Is it safe to assume that I might get a bit more mouth leakage with the higher pressure? and that as long as my apneas are being controlled, I just won't worry about a little more mouth leakage?
Yes, its much more common to mouth breath at higher pressures, even with a chinstrap.

As for whether you should worry about it, that depends on the leak numbers. On the AutoSet, you want to avoid long periods of leaks at or above 24 L/min (the so-called ResScan Red Line). If you have extended periods of leaks above 24 L/min, the data may not be accurate and the true AHI may be higher than the reported on.

So what do your leak numbers and leak graph look like?

Quote:I am still very new to this, so there is a LOT I don't know! All I do know is that I'm happy to finally have treatment for apnea (after YEARS of suffering) and I regret not getting treated sooner.
You've got a great attitude! And that's a real plus if/when you start to hit some difficulties.




RE: Couple of questions about APAP - jaycee - 06-05-2014

IMO, there are a few good reasons to use APAP:

1) When you have a poor titration study. It's very difficult to narrow down your "optimum" pressure if you don't much sleep in the lab.

2) When you don't have a titration study. Many insurances are opting for this. Home PSG (cheaper) and then Auto CPAP (the DME eats the costs).

3) When you are very positional in your therapy. You might require 14 on your back but only 8 on your side. With straight CPAP you are either going to get your pressure set too low (either 8 or somewhere in between 9 and 13) or you have deal with the higher pressure of 14 all the time.

4) A "poor man's sleep study" for a short trial period (2-4 weeks) instead of going back in for another titration.

APAP are probably over-prescribed when it comes to "need". It has become more of a "want" by many patients/providers even though they don't really know exactly why they want it. Ideally insurance would pay extra for APAP (or the patient could pay the cost difference if they choose to upgrade).


RE: Couple of questions about APAP - Buckeyedog - 06-05-2014

Wow Kathi, you sound a lot like my situation. Although seems like I got set up right away with a VPAP as mine is basically central apnea I guess.......after struggling for 20 years or so from this. I have been doing pretty good with it for the first two weeks, but have had the dry mouth on occasion. I don't really understand it all right now, but reading this forum has helped somewhat. Still confusing, but getting better. I sure hope you get your stuff sorted out. Sounds like you are on your way.


RE: Couple of questions about APAP - jaycee - 06-05-2014

Let me start by saying I would never put someone on an APAP without a doctor's order. Plenty of times I have "recommended" APAP settings to a patient or doctor, but I would never just set someone on APAP after their doctor ordered CPAP.

I prefer "tighter" APAP settings. 5-15 to start out and then adjust from there.

Low pressure = as high as what you feel comfortable with. As you get more used to the pressure then start inching up that 5.

High pressure = just a tad above your your 95 (or 90 depending on brand).

So, if I was setting someone that had an optimum pressure (as determined by titration study) of 11, I would probably start them at 5-12 and then go from there. I would ask them to take a deep breath on 5 and then ask them if they felt the air was coming fast enough for them. If no, then increase to 6 and repeat until I felt they were comfortable with starting pressure. Big guys will generally need 6 or higher. A little old lady I might start at 4 but only if they looked to not tolerate 5.

Also remember another downside of APAP. Mask fit. People often mistakenly fit their mask at the low pressure and assume everything is good. Then the APAP pressure increase, their mask starts leaking and they end up waking up.

As a general rule of thumb, make your starting mask tightness just a little bit tighter than you really want it. It might take you a couple more minutes to go to sleep but you will be less likely to wake up due to mask leak issues (but not too tight to the point you have skin breakdown issues).


RE: Couple of questions about APAP - zonk - 06-07-2014

(06-05-2014, 01:12 PM)jaycee Wrote: So, if I was setting someone that had an optimum pressure (as determined by titration study) of 11, I would probably start them at 5-12 and then go from there.
Why would you start someone at 5, if 11 is optimum CPAP pressure
For me, would feel like not getting enough air to breathe for a start and allowing heaps of events to slip by until the machine reach treatment pressure, and only to go back towards the low starting pressure once thing get stabilized and the same things start over, over, and over again


RE: Couple of questions about APAP - Sleepster - 06-07-2014

(06-05-2014, 12:02 PM)kderevan Wrote: My mouth was dry when I woke up, so I think that at the highest pressure I'm doing some mouth breathing even with the chin strap, getting some leakage out the mouth.

Look at your SleepyHead graphs and see if the extended periods in large leak are accompanied by higher pressure.

Quote:Is it safe to assume that I might get a bit more mouth leakage with the higher pressure? and that as long as my apneas are being controlled, I just won't worry about a little more mouth leakage?

It's likely that the higher pressure will cause more mouth-leaking.

When you are mouth-leaking the machine can't accurately measure your AHI. You must get the leaks under control. Nothing else is as important.

When you're in large leak the machine can't maintain the pressure splint and your airway can collapse, just as it would if you had no CPAP machine at all.

Consider lowering the high end of your pressure range. If that controls your leaks and keeps your AHI below 5, clinically your treatment is effective. Of course, once we get there we want to lower the AHI even more. If the pressure you need to keep your AHI below 5 is so high it causes mouth leaks, the only remedy is a full face or hybrid mask.

Before I'd do any of the above, though, I'd tighten the chin strap a bit. I start mouth-leaking when my chin strap gets too loose from wear and I have to tighten it some more.



RE: Couple of questions about APAP - retired_guy - 06-07-2014

(06-05-2014, 12:02 PM)kderevan Wrote: The DME guy said he was going to set my pressure from 10-20 (based on my prescribed pressure of 11) but I think he may not have done it, since my reported pressure ranges from 8 to 19.5.

You would see a low of 8 instead of 10 if your EPR is on and set to "2".

That tells the machine to reduce the exhale pressure by 2, so if your low pressure is 10, you end up with an 8.

That's actually just fine as long as you're comfortable and your events are being taken care of. Otherwise you could increase your low end to 12 which would result in 12 sometimes, and 10 sometimes.



RE: Couple of questions about APAP - Sleepster - 06-07-2014

(06-07-2014, 01:26 AM)retired_guy Wrote: You would see a low of 8 instead of 10 if your EPR is on and set to "2".

That tells the machine to reduce the exhale pressure by 2, so if your low pressure is 10, you end up with an 8.

I don't use a ResMed machine, but on my machine that's not true. If the pressure is set at 10, then the machine reports a pressure of 10 regardless of the EPR setting.