Not Getting Enough Air

[Midge 82]

Hi. I'd love some help with my current issue, which is the feeling that I'm not getting enough air. I awakened last night, gasping, which is how I used to be before treatment five years ago. I've been having trouble sleeping lately, and I think it's related to this problem.

I have mixed Central/Obstructive apnea, but Central is primary. I use a Resmed Air Curve 10 ASV (other details below). I've responded very well to treatment until recently. My crazy erratic high bp is normal now, and I have felt a lot better most of the time.

However, sometimes recently I have the feeling that I'm not getting quite enough air. Last night was extreme; I kept waking up, gasping for breath. I had not changed the settings. I had the sensation of having to force my breathing, which is pretty shallow (even during the day) unless I'm consciously breathing. It also felt like maybe the the air pressure was lower than it should have been (less air coming out of the hose), but I wasn't sure. I kept checking to make sure air was coming out of the mask, because it almost felt like I wasn't getting much.

I don't know how to tell if some piece of the setup is malfunctioning, if it's the machine, or if the settings need to be changed. I've just washed my extra mask and hose, in case it's one of those components leaking or something, but I'm doubtful that that's the problem.

I'd be grateful for any suggestions. My settings are listed below (and please note that the numbers below are correct; I have not yet figured out how to change my profile settings on the left side, which are old and not correct).

ASV Resmed Air Curve 10 with Dream Wear Mask


Settings: ASV Auto
Min EPAP: 5
Max EPAP: 8
Min PS: 2.0
Max PS: 12
Mask: Nasal
Ramp Time: Off
Humidity Level: 2
Tube: Slim line 
AB filter: No

[SarcasticDave94]

It's best to see an OSCAR screenshot, but having used this same ASV in the past, experience says raise your EPAP Min. Try EPAP Min 6 and see if they helps the air starvation feeling.

[Midge 82]

It's best to see an OSCAR screenshot, but having used this same ASV in the past, experience says raise your EPAP Min. Try EPAP Min 6 and see if they helps the air starvation feeling.

Thank you for your response. I will try your suggestion. I don't know enough about this to know how it could help, but I also wonder if raising the inspiration pressure could help? 

Thanks,
Midge

[SarcasticDave94]

Inspiration or IPAP, is not directly user adjustable. Indirectly, by editing EPAP and PS, IPAP can be changed. I would not edit all that at this time, until data is seen. Even then, it may not be a best decision.

[Sleepster]

If you have the ramp feature enabled, I recommend you turn it off.

I'm sympathetic to people who think they aren't getting enough air. But the lowest the pressure will go is 4, and we walk around all day breathing air at a pressure of 0. I recommend that when you get the feeling that you're not getting enough air, you do something to relax yourself.

[staceyburke]

I'm sorry but I disagree.  We do walk around all day at 0 but we can breath more oxygen than with a mask on our face that if it is correctly fitted does not allow more than 4.  The mask shuts off all other air it is like breathing through a straw if there is no other place for the air to enter.

I'm on oxygen of 4 ltrs 24/7 but the cannula allows for more air to come in not just the oxygen enriched air.

[staceyburke]

Here is a picture of the cannula I use on my glasses, they can supply 5 ltrs, I am using 4.  Do you really think I could get enough oxygen through those???

[SevereApnea]

Midge: warning: long ramble here. Just replying from left field here. I am not trying to be controversial. Just trying to add something for you to think about and work with.

My own experience and sleep notes suggest that too low a pressure causes me to feel what I call Air Starvation. Exactly that, I need to remove the mask (Get the * Mask Off feeling = GTMO feeling) and have to get up for an hour or two to "get my breath back" before I face the mask and PAP therapy again. I call that Recovery Breathing. Perhaps this is what you are feeling?

I used to try and go as low as possible with my EPAP, as low as 4.8 or 5.6. If I kept this up for a few days running I would be breathing hard all day: I call this Air Hunger: needing to take deep breaths all day. Despite my O2 levels being 92 - 98% all night. Hence, for me anyway, it is not O2 related.

My own suspicion (unfounded) is that there may not be enough venting of C02 at such low pressures, and that that is what gives me the short term feeling of Air Starvation. If I allow this to build up over a few days I land up with longer term Air Hunger: involuntary deep breathing (Respiratory Acidosis?) spending the whole day trying to blow of CO2/HCO3- (bicarb), perhaps? 

Maybe the specific Mask Vent holes/EPAP settings do not allow me to clear enough CO2 from the dead space? I used to lie awake at night deliberately creating some mask leaks to get rid of that horrible Air Starvation feeling, and felt it did help short term.

Anyway that is my working hypothesis. (Like I said I am coming from left field here. Supposition only. No science here, pinch of salt etc) 

Importantly, with trial and error, I have all but eliminated that feeling by using a higher EPAP, currently around 7. 0 - 7.4.

I now have Minimal leaks from my current HeadGear/Mask setup so it is critical that I maintain the correct EPAP to maintain sufficient venting.

Now, I still don't understand the details about Atmospheric pressure vs Pressure with a mask: I have long since given up trying to rationalize this to myself. Walking around at atmospheric pressure I know that I am getting enough Oxygen, but there is no mask with vent holes in front of me. And no long tubing increasing my respiratory dead space. That is, nothing affecting my C02 elimination. (Again, just supposition). Not to mention reduced Vt and MV when sleeping versus being awake. Anyway, enough rambling....

So, yes totally agree that you try and up the EPAP. Might I also suggest you make meticulous notes daily when you wake up, describing how you feel, what you feel. Make up new words to describe what you are feeling, if necessary. This is personal to you. Review your notes as often as you need to. Eventually you will see a pattern that is relevant to you, and the penny will drop. So much of this journey for me is personal, and often paradoxical!

This may be one part of the puzzle for you.  I can't comment on your other machine settings, but I am sure others will offer more help soon.

All the best!

[ThisIsNotHowIAm]

Midge: warning: long ramble here. Just replying from left field here. I am not trying to be controversial. Just trying to add something for you to think about and work with.

My own experience and sleep notes suggest that too low a pressure causes me to feel what I call Air Starvation. Exactly that, I need to remove the mask (Get the * Mask Off feeling = GTMO feeling) and have to get up for an hour or two to "get my breath back" before I face the mask and PAP therapy again. I call that Recovery Breathing. Perhaps this is what you are feeling?

I used to try and go as low as possible with my EPAP, as low as 4.8 or 5.6. If I kept this up for a few days running I would be breathing hard all day: I call this Air Hunger: needing to take deep breaths all day. Despite my O2 levels being 92 - 98% all night. Hence, for me anyway, it is not O2 related.

My own suspicion (unfounded) is that there may not be enough venting of C02 at such low pressures, and that that is what gives me the short term feeling of Air Starvation. If I allow this to build up over a few days I land up with longer term Air Hunger: involuntary deep breathing (Respiratory Acidosis?) spending the whole day trying to blow of CO2/HCO3- (bicarb), perhaps? 

Maybe the specific Mask Vent holes/EPAP settings do not allow me to clear enough CO2 from the dead space? I used to lie awake at night deliberately creating some mask leaks to get rid of that horrible Air Starvation feeling, and felt it did help short term.

Anyway that is my working hypothesis. (Like I said I am coming from left field here. Supposition only. No science here, pinch of salt etc) 

Importantly, with trial and error, I have all but eliminated that feeling by using a higher EPAP, currently around 7. 0 - 7.4.

I now have Minimal leaks from my current HeadGear/Mask setup so it is critical that I maintain the correct EPAP to maintain sufficient venting.

Now, I still don't understand the details about Atmospheric pressure vs Pressure with a mask: I have long since given up trying to rationalize this to myself. Walking around at atmospheric pressure I know that I am getting enough Oxygen, but there is no mask with vent holes in front of me. And no long tubing increasing my respiratory dead space. That is, nothing affecting my C02 elimination. (Again, just supposition). Not to mention reduced Vt and MV when sleeping versus being awake. Anyway, enough rambling....

So, yes totally agree that you try and up the EPAP. Might I also suggest you make meticulous notes daily when you wake up, describing how you feel, what you feel. Make up new words to describe what you are feeling, if necessary. This is personal to you. Review your notes as often as you need to. Eventually you will see a pattern that is relevant to you, and the penny will drop. So much of this journey for me is personal, and often paradoxical!

This may be one part of the puzzle for you.  I can't comment on your other machine settings, but I am sure others will offer more help soon.

All the best!

I may be experiencing this with the f30i as well, I wake up every night after about 20 min with a sharp inhale, I suspect from CO2 build up. I tried upping the pressure but get aerophagia. Have you found any masks that may have a smaller co2 buildup?

[CorruptAlligator]

If you have the ramp feature enabled, I recommend you turn it off.

I'm sympathetic to people who think they aren't getting enough air. But the lowest the pressure will go is 4, and we walk around all day breathing air at a pressure of 0. I recommend that when you get the feeling that you're not getting enough air, you do something to relax yourself.

This is how I thought of it when I first started therapy.  The machine is pushing stronger airflow due to greater pressure.  So, I kept it at minimum 5 with no issues (of breathing) and was confused when people says under 7 is for children?  

Shouldn't 0 or normal atmospheric pressure be worse than 'childrens' level of pressure?

It makes sense what they tell you when you start. They say pressure might be too much since you are not used it.

The point about breathing through (if no pressure is applied and detached from the machine), air input is somewhat more resistant due to narrow passageway air is pulled from.