What is CPAP supposed to feel like? and actually do?

[Maddcow]

Hi all.
What is CPAP therapy supposed to feel like? I've been using CPAP for about 2 1/2 months now and started out with a Swift II for 2 weeks and then changed to an Activa because of constant leaks when sleeping on my side with the Swift.

With the Swift it was easy to differentiate between pressures because of the direct "injection" of air to my nostrils but with the Activa, I can hardly even tell that I'm wearing it because of the air diffusion in the mask. I certainly don't feel any "pressure" in my airways. I even tried 20cm last night and apart from the greater pressure on the mask itself and the resulting effect on my ears, I couldn't feel any difference whatsoever with the airflow into my nostrils from pressures of 11, 13, 15 and 16. Am I supposed to? I thought that CPAP was supposed to "force" my airways to stay open but I just can't see how it's supposed to do this when I can't even feel any air pressure in my nostrils with the Activa. With the Swift, I could definitely feel the constant air pressure and could also easily discern pressure differences....but with the Activa, it just feels like I'm breathing in a regular oxygen mask like you may use in a hospital for asthma etc. I certainly don't feel any air forcing my airways open.

I was initially titrated with 13cm with an Activa large mask but am using a medium now because the large leaked a lot. From other threads I've started, some of you may know that I've been experimenting with different pressures trying to find what works for me but have not managed to get my AHI below 7......most of the time it fluctuates between 11 and 17, regardless of leakage (which is now at an absolute minimum because I tape my mouth and the mask seal is excellent). I've also tried about 13 other masks over the past 2 months....most of which leaked badly. The Activa was the only one that I could get to seal well - and it really does seal well generally.

BUT, I'm wondering if the medium Activa mask is somehow not allowing enough air pressure into my nostrils. I just can't see how air coming into the mask via the tube can possibly get into my nostrils when the bottom of the mask sits so close to the bottom of my nose. In fact, the base of my nose has been getting little sores from rubbing on the thicker inner membrane of the mask.

Can anyone help to explain what's going on here? My daily results show that I'm constantly experiencing hypopnea events every night, regardless of whether the leak rate is, say, between 0-2L/min or up to 24L/min. In fact, it seems like hypopneas and apnoeas generally appear to be less when I experience leaks!?!?!? But using a lower pressure definitely causes more apnoeas. What the heck is going on??

Thanks heaps in advance,
Gary

EDIT: Just checked my historical data and AI and HI definitely appear to be less when I have leaks, whereas these rates are generally almost constant when leak rate is close to 0. Isn't this the exact opposite of what CPAP therapy is supposed to achieve?

[jskinner]

In fact, it seems like hypopneas and apnoeas generally appear to be less when I experience leaks!?!?!? But using a lower pressure definitely causes more apnoeas. What the heck is going on??

If the leaks are bad enough the machine can't detect hypopneas and apnoeas.

[Wulfman]

The principle is the same, but I think it's different things for different people.

Principle: Keep the airway open with pressurized air to allow breathing.

It took me some time of reading about all the different things that people (on the forum) had been having done to somewhat diagnose my own situation.
First clue: I've been a "mouth-breather" all my life.
Second clue: I had my nose broken in high school playing football.
Third clue: I found out early on that I needed cool air (from my CPAP) at night to keep my nasal passages open.
I'd never heard of "turbinates" before coming on the forum and while I've heard of "deviated septum", I had no reason to connect the dots to my situation. Now that I know about turbinate reduction and septum surgery, I believe that at least the turbinate thing is part of my problem. If I can't breathe through my nose when I'm sleeping, I have to open my mouth.....and when I do that, it sucks my tongue back in my throat and cuts off my air supply........APNEA events.

I've also noticed that I can breathe a little better inside my mask when my leakage is a little higher, too. Obviously, I'm getting more air.

At this point, I don't have any plans to explore the turbinate or septoplasty surgery, but I keep wondering how much difference it would have made in my situation if I'd have had it done years ago.

Did either of my doctors even ask me or try to find out if I could "breathe" when I'm sleeping?.......No!

Now that I've got a sufficient amount invested in this therapy, I'll just keep using my CPAP and breathing well when I sleep.

Den

[Needsdecaf]

I think it may be a case of you getting used to it. I assume that in your test, you had your mouth firmly closed. As such, you are likely containing the air as you are supposed to.

I remember when I first started, I could feel the pressure on the inside of my airway. Now, I feel nothing. Feels completely normal. And this is with a FFM, so it's not all going out my mouth or anything like that.

[Maddcow]

Ok, so you guys don't feel any air "pressure" in your nose when breathing in? It just feels like breathing normally?

And do you guys feel any resistance when breathing out? I don't even feel resistance when breathing out, even when the pressure was 20cm last night. The only thing that felt different was the amount of pressure on/around the mask itself and my face i.e. I was breathing in an increased-pressure environment rather than having more pressure directed into my airways.

Perhaps I'm misunderstanding something about CPAP principles: Is it more about the amount of pressure that's generated within the breathing environment (i.e. face area & therefore nose/airways) than about the amount of pressure that's directed into the nose/airways? I guess I could put it this way: is it more like scuba diving where the pressure of the air increases as you get deeper but the amount of air being breathed in remains the same? I'd always assumed that CPAP is about having air forced into your airways to force them to remain open.

[ww]

It is about pressure above static room pressure in your mask and therefore in your airway being higher than the pressure outside your airway in your body keeping your airway open. It has little to do with the velocity of the air going in or out, although this obviously affects the pressure a certain amount. After you get used to it, you do not notice the pressure or airflow and sometimes wonder if someone turned the machine off!!!

[bigk]

I noticed you have the S8II - don't worry - you will never feel any resistance breathing with that machine.

[Snoredog]

CPAP doesn't feel like anything, it RESTORES normal sleep. It does that by preventing Sleep Disordered Breathing (SDB) "arousals".

Every time your airway becomes blocked where you cannot breathe it creates an arousal which can be seen on EEG monitoring equipment. The arousal follows the event, so if you can prevent the blockage or apnea, you can eliminate the arousal and interruption to your sleep.

There there are other physical benefits such as elimination of the associated hypoxia and how that impacts your overall health.

[Claire]

The poster above was right. Your S8 has a setting that reduces the pressure when you breathe out so that you don't have to struggle against the pressure.

I had a nose mask and then moved to pillows. I definitely feel the pressure more with the pillows than with the mask.

I think the point is to keep your AHI under 5. I have noticed quite a variation within that range and it's not related to leaks. For awhile I kept a diary to see if I could pinpoint what made the variation occur...medication, allergies, level of exercise, etc. I have not been able to find out why...it may just be a normal variation because we change from day to day.

Anyway, I wouldn't personally play around with the pressure unless my AHI was consistently over 5. I think stability is important...going to bed roughly at the same time, having the same mask experiece, etc...helps toward relaxing so you can forget about the mask and fall asleep!

[ozij]

The scuba analogy (or even experience) is probably confusing you.

CPAP pressure is there to splint your upper airway open, keeping just enough pressure in it to keep it from its (un)natural tendency to collapse. The pressure of a Bi level cpap machine at its highest is 25 cms H2O, other CPAP machines max at 20 cms - nothing compared to the pressure needed in scuba gear to keep you breathing in the deep.

CPAP (Continuous Positive Air Pressure) does not - cannot - force your airway open once it has collapsed and is obstructed. With enough baseline pressure, your machine will hopefully keep your airway from full collapse/obstruction (apneas), partial collapse/obstruction (hypopnea). Wise machine algorithms may be capable of adjusting your pressure based on collapse/obstruction precursors (flow limitations) - but none go barging through existing obstructions to force your airway open.

O.

[khvn]

...
With the Swift it was easy to differentiate between pressures because of the direct "injection" of air to my nostrils but with the Activa, I can hardly even tell that I'm wearing it because of the air diffusion in the mask.

...

I thought that CPAP was supposed to "force" my airways to stay open but I just can't see how it's supposed to do this when I can't even feel any air pressure in my nostrils with the Activa. With the Swift, I could definitely feel the constant air pressure and could also easily discern pressure differences....but with the Activa, it just feels like I'm breathing in a regular oxygen mask like you may use in a hospital for asthma etc. I certainly don't feel any air forcing my airways open.
...

Although it doesn't blow wind directly into your nostrils like the Swift, but that does not mean that the Activa is not working. Here's how to prove that to yourself: Try talking wearing the Activa with the blower on. You'll see that the wind blowing out of your mouth distorting your speech.

That pressure is what keeps your airways open although you can't feel they open (just like you can't feel your veins open but you know they are and blood is circulating through them).

[Moogy]

There is an immense difference in the amount of pressure that I feel when using the Activa rather than the Swift.

And I CAN talk with the Activa on, even at relatively high minimum pressure.

I would be concerned though, if I could never get my AHI under 7. I can usually manage around 1-2.

Moogy

[khvn]

It's the blower, not the mask that determine the pressure applied to your airways. So, assuming the same vent/leak rate, either the Swift or the Activa mask would deliver the same pressure. Of course, you still can talk with any mask on, it's the air escaping from your mouth that's the proof that your airways are pressurized by the blower.