can too-high pressures be harmful?

[ellen1159]

Forgive a dumb newbie question, but if your pressures are set higher than necessary on a bi-pap machine, can that make it harder to breathe when you're not on the machine? Can you do damage to your lungs?

I find that I inhale very long and deep and that it's hard to control with the pressure settings I have (15 min 25 max but I"ve never seen the display go higher than 21). Exhale is not a problem because I have the flex setting on max relief. When I take off the mask an hour later it feels like it takes an effort to draw in breath.

I have been advised by some members to speak to my doc about lowering my pressures, but I thought he might be reluctant to do so (his assistant discouraged me, said I could get air hunger) so I thought I'd try to adjust until my next appointment, in 10 days, and if I wasn't able to fall asleep by then, I'd talk to him about reducing them.

I've gone back to my Mirage Quattro FFM because it's easier to tolerate the high pressures but even though it seems to be the right size for my face, it still leaks and the tension of the headgear is just enough to keep me from drifting off to sleep.

Is there a consensus on the newer version, the Quattro Air? Is it more comfortable? Does it leak as much?

[Tez62]

Ellen, there are no dumb questions you need to get the answers you want, it shouldn't cause damage to your lungs as it should only be at a high pressure when it detects an apnea when should go back down to the low pressure. Have you or the assistant looked at you data, that would be the first thing to do, we can help you load the free software on your PC and show you how to read your data. Do you know what your AHI was at your first sleep study? A high pressure of seems very high but it is possible you need it. At that pressure it will be very hard to keep any mask on especially if you move in bed.
I also use the Mirage Quattro, I live in Australia so haven't seen the Air yet but are looking forward to trying it, because it is so much lighter you could possibly have problems keeping it on at a high pressure. Please let us know about you figures so we can try to help, I would agree with the others that possible your high and low pressures are too high.

[RonWessels]

To put the pressures into perspective, imagine having a tall glass of water perhaps 6 inches tall. Put a straw all the way to the bottom and blow bubbles. That is equivalent to exhaling against a CPAP pressure of 15 cmH2O.

Take a balloon and attach it to a CPAP delivering 20 cmH2O pressure. What happens to the balloon? Does it blow up? Well, not really.

[trish6hundred]

Hi ellen1159,
There are no dumb questions so don't sweat that.
Just hang in there for more answers to your post.

[vsheline]

if your pressures are set higher than necessary on a bi-pap machine, can that make it harder to breathe when you're not on the machine? Can you do damage to your lungs?

I find that I inhale very long and deep and that it's hard to control with the pressure settings I have (15 min 25 max but I"ve never seen the display go higher than 21). Exhale is not a problem because I have the flex setting on max relief. When I take off the mask an hour later it feels like it takes an effort to draw in breath.

I have been advised by some members to speak to my doc about lowering my pressures, but I thought he might be reluctant to do so (his assistant discouraged me, said I could get air hunger) so I thought I'd try to adjust until my next appointment, in 10 days, and if I wasn't able to fall asleep by then, I'd talk to him about reducing them.

Hi ellen1159, welcome to the forum!

Please ask for a copy of the full sleep report from your sleep study. Please ask for a copy of your CPAP prescription, also. You are entitled to keep copies for your own records. There is important information in the report, as to why your prescribed pressures are as high as they are.

And if you ever fly and want to take your CPAP machine with you as medical equipment (so it does not count toward your normal luggage allowances and so you can use it when sleeping on a long flight) you will need to show a copy of your prescription.

Blowing up a balloon takes much more pressure than 25 cmH2O. A cough will produce much, much more pressure. So the lungs will not be hurt by the CPAP pressure. It takes about 70 cmH2O to equal just 1 pound per square inch of pressure.

It sounds like your machine is set for 15 cmH2O on every exhale and to allow up to 25 on inhale. What does your prescription actually say?

A Pressure Support (which is the difference between inhale and exhale pressures) of 10 will normally be enough to do nearly all the work of breathing, and your lung muscles would be mostly resting if the Pressure Support were to get as high as 10.

So if the PS is normally 5 or 6, the machine would be doing about half of the work for you. Therefore, it is perhaps not unexpected that you would notice the extra effort in the morning when no longer using the machine.

But unless you are having trouble breathing without the machine and need a portable ventilator machine to carry around with you during the day (some do), I think there is no need to be worried about it. Talk to your doctor about it, of course, but I doubt he will see reason for concern.

If your doctor is a sleep specialist, he should be able to read the data card from your machine to see how you are doing. Call his office to make sure he is set up for this. Maybe he will want you to drop off the data card a day or two before the appointment, so he will have time to look at the data before your appointment.

But I suggest downloading the software from this forum and looking at the data yourself, if possible, before your appointment, and maybe describing or posting the data for comments on this forum.

You could ask the doctor about possibly reducing your pressure, but this is a decision which really should be made after looking at the data in the card. (And after understanding the sleep report from your sleep study, so feel free to ask the forum and your doctor questions about anything you don't understand in the report.)

Specifically, your machine is an Auto machine which can be adjusted to operate at a lower exhale pressure than 15 and only raise itself to a higher pressure automatically when needed. If this is not how your machine is adjusted, the reason should be in the sleep report.

If the data on your machine's card never shows obstructive apneas, it would seem reasonable to me to set the minimum exhale pressure lower, and to set the machine to automatically raise its pressure higher when needed.

I've gone back to my Mirage Quattro FFM because it's easier to tolerate the high pressures but even though it seems to be the right size for my face, it still leaks and the tension of the headgear is just enough to keep me from drifting off to sleep.

Is there a consensus on the newer version, the Quattro Air? Is it more comfortable? Does it leak as much?

I have not tried the Quattro Air. I have used the Mirage Quattro with a ResMed Gecko nose pad to stop leaking around the nose and to allow it to be worn a little looser. I suggest you try one.

I also have used the Quattro FX, but I find it really helps to use a Mask Liner with it, such as made by RemZzz.

Mask liners go between the face and the mask and allow us to wear the mask a little looser, because leaks are softer and less noticeable when using a mask liner.

Take care,
--- Vaughn

[skyler]

As a five year CPAP user I don't have copies of my sleep studies, don't keep a prescription handy, and rarely use software. I'm doing great. Just another opinion and point of view.
I tried the new Quattro Air, but unfortunately bought a size too small. It was very comfortable and seemed to fit- resting right in the cleft between bottom lip and chin, but would ride up in the night and leak. I think had I bought a large it would have been fine.
As others has said the only dumb question ins the one not asked. We were all strangers to CPAP when we started. It took me five years to get it right. Keep asking questions and it won't take you that long. Good luck.

You are on high pressures. Not everyone approves of this, but I take 50mg of Benadryl and it helps me sleep through the night. If you don't sleep long enough it can cause some drowsiness in the morning, but I don't have that problem. BY all means discuss this pressure with your doc. That's what he/she is there for and they can't help you if you don't talk to them. One thing I do advocate is writing down questions so when you go for a checkup you can be brief still and cover everything.