Straining to inhale

[lavern]

Hi All!  I've been on CPAP for 10 months now and have sorted out many of the various problems and learning curves that come with it. Generally it's going great and I'm really happy with my setup, although I still have days where I wake up feeling not very well rested and I have a theory as to why.

One of the few remaining issues I have is this: It is sometimes as though the machine is not delivering enough air for me to breath normally and I am fighting or straining against it to breath in.  It's like a lesser version of how it feels when your machine is not powered on and your trying to breath through it.  Last night I was actually dreaming that someone had put a sock over my machine's airway (or something like that), and then awoke to discover that I was indeed straining to inhale. For a second I thought the power had gone out but then realized the machine was still on, just not giving me the air I needed.  This only happens sometimes and I don't know why. As I consciously slowed my breathing I stopped having to fight the machine and it seemed to be otherwise working fine.  The thing is, if the machine is supposed to to deliver a constant pressure, shouldn't it be able to do that regardless of how fast or slow I breath?  Is there something wrong with the machine that this is happening?

I have almost no obstructive apneas but I do get about 2 CA events per hour so I wonder if when I try to breath faster to catch up from those CAs the machine cannot deliver enough air ?  It's occurred to me that this may be happening a lot throughout the night, and I'm having a lot of periods where I'm not getting as much air as my body needs after those events.

I'm currently at 6cm fixed, with EPR turned off. I'm thinking I'm going to turn it up to 7cm but I know that as the pressure goes up, so do CA events, mouth breathing and aerophagia.

Would appreciate any thoughts on this. If I should post a chart are there any particular graphs that are more important to look at for this?

Thanks!

[staceyburke]

Your be min pressure is to low. 5 is not giving you enough air. Most adults need at least 7 to 8 to feel like they can breath normally. I take min 10 or I feel air starved.

I would start with min 8 and adjust up or down.

[Deborah K.]

I suggest you set a pressure range of 8-16.  If you are not using EPR turn it on full-time set at 2 or 3, and if you are using ramp turn it off. You get no useful therapy during ramp.

[mesenteria]

If it matters, I agree that your fixed pressure is too low, probably by at least 2 cm H2O.  I happen to be able to get away with that, even with severe apnea, because it works for me...that's all I seem to need. However, I do have a lower limit of 6 set with EPR of 2.  I agree with the others about EPR....put some into your settings, and I think you should consider at least 8 fixed, probably 9 or 10.  Be patient and see what effect the new pressure has on your CAs first, with no EPR, and if it looks good for three or four days, try adding one, then two cm of EPR.  If your CAs return, you know what to do.

[lavern]

Appreciate all of the replies! I'm going to try upping the pressure to 8. 

I have EPR turned off because I do seem to get increased CAs when it's on. Months ago someone here gave me a very good explanation for why this is: because the lower pressure on exhale allows the lungs to clear out more CO2, which lowers the brain's trigger to inhale, since it is the presence of CO2 that triggers the body to breath. So what is the reason to suggest turning EPR on for not getting enough air flow? I am open to experiment with it again and see if anything has changed for me... Just want to understand what the rationale is. I'll definitely start with just the pressure change first. Thanks!

[SarcasticDave94]

EPR can act like a leverage, higher inhale then when EPR reduces pressure your lungs naturally expel air. If you've been on CPAP 10 months, those likely treatment emergent Central Apnea should have diminished.

Were the Central Apnea on your sleep study? How many CA are you talking about here?

[40plus]

What kind of mask do you have and what is your mask setting in the resmed 11´s settings?

The settings will alter how the air is delivered. Full face setting delivers air the most gentle , then nose is medium and nose pillow the strongest delivery of air.

Using the full face setting while wearing nose pillows makes me feel very air starved so do check your settings.

As already mentioned also set minimum pressure of 8 and have ramp turned off. Also use manual start and stop, not automatic so there is no chanse the machine stops on its own. And dont use EPR. If your ahi is low, no issues with leaks or swallowing air and your sleep quality is good there is no need for epr as it might increase the central apneas for no added benefit.

If this feeling persists go to ent and check your nose for obstructions like deviated septum, enlarged turbinates or other issues that might make it hard to breathe.

[Jay51]

EPR can give a little, "umph" or "boost" to a person's inhale to help them overcome flow limitations, hypopneas, etc. as the pressure increases after exhale: which is then added to a person's own spontaneous inhale (like adding momentum).  The downside is that it can wash out too much CO2 on the lowered exhale pressure (like Dave explains).  And like adding some momentum to the exhale also (and possibly comfort also exhaling).

Definitely a balancing act.  People can react differently to EPR also - can help some and hurt others.

[Deborah K.]

A few CAs per hour is nothing to worry about. Use the EPR as it will lower flow limits and make your breathing more comfortable.

[lavern]

Just replying to all here. Once again thank you for the insightful replies!

@SarvasticDave49 My original sleep study only showed 6 CA events for the night. My titration study didn't seem to show any (or they didn't mention it). I just reread the report to double check. EPR was off during titration study. I'm getting around 2 CA per hour without EPR and that goes to 3 or 4 with it on.  

@40Plus I'm using P10 pillows and do have the machine set to pillows mode. I've never used ramp.  Interestingly, I do have a problem with swollen turbinates and am being assessed next month to see if I'm a candidate for a reduction procedure, however I don't think that's a factor here. My nose is not always obstructed and that is a much different sensation (like having a stuffy nose). If anything that CPAP actually helps overcome this to some degree.

Running it at 8 (not min, but fixed) felt great last night.