C02 buildup question

[Aaronmandevill]

I’m still trying to get used to bipap so most nights I end up pulling it off sometime during the night. Getting more comfortable but had a question about C02 buildup. When I wake in the morning I am starting to get headaches and figured that’s from C02. If that’s the case would bipap help in that regard? Seems the bipap only helps with inward pressure so having issues exhaling wouldn’t help right? I guess full ventilation is the only thing that helps with exhaling? I know I’m rapid progression but just wondering if this is only a later stage symptom. My family refuses to see me or spend time together until my Houston Methodist second opinion but that is 4 weeks away.

 

[Bestfriends14]

Bi-pap (Bi means two), both pushes air in and pulls it back out so, yes, it prevents CO2 build up (if the settings are correct).

 

[Aaronmandevill]

Oh that’s a relief thank you for that!

 

[Jimi]

A bipap has two pressure settings. Higher pressure for inhaling and a lower pressure during exhale. Both provide positive pressure. A bipap does not provide negative (suck or pull) pressure and neither do ventilators (that I know of). You are describing a c02 headache for sure. I suffered those for a while before getting a bipap. By having sufficient in and out pressure differences your lungs can move the proper amounts of air and give you oxygen while removing c02 . ALS patients should not use a CPAP because it only has one pressure and won't help move air in and out.

 

[swalker]

I also suffered from headaches before getting the bipap. Those headaches persisted while we got the bipap parameters set properly for me.

My pulmonologist stated CO2 was the likely cause for the headaches and prescribed the bipap.

I have been using a properly adjusted bipap every night for about 18 months. I typically use it between 10 and 16 hours a day. I rarely have a headache when I wake up now.

I also seem to have more stamina during the day now that I am using a bipap.

Steve

 

[lgelb]

To be clear, BiPAP does not prevent CO2 buildup forever, because there is no negative pressure to compensate for the loss of exhalation musculature, but (properly adjusted over time -- not a set and forget product) -- should do so until the very end stages. Part of that is typically using the lowest possible EPAP (pressure that you exhale against) unless there are certain pre-existing lung problems. Another is adjusting the volume/timing of each breath so that you aren't taking in more air than your muscles can expel as CO2.

Sounds like we don't have your settings quite right, Aaron, and/or a different mask might help -- I will email you.

 

[Aaronmandevill]

Thank you @lgelb I really appreciate you working with me to get things down. It’s much closer than when I first tried it out for sure. Feels close to being comfortable. I have 3 masks but am up to try other options as well I know there’s lots out there.

@Jimi and @swalker Thanks so much for the reply I know how hard it is to type these things out.

If C02 buildup is the issue you wonder why they don’t make a machine that also pulls the oxygen out, seems it would be possible.

 

[affected]

The machine needs to pull the CO2 out, not the O2 (although that is probably what you meant, it's important for other readers now or later to be clear that O2 goes in, CO2 goes out).
The machine that does that only really works when you are intubated or have a tracheostomy, then it literally breathes for you completely and you don't need any ability to breathe.
To use a bipap type machine with a mask, it can only use the pressure differences to assist you in breathing CO2 out, but you need some functionality for it to work.
That is why, at some point, some PALS move from bipap (not invasive) to fully invasive ventilation.

There is a lot to take in at first. I hope Laurie was able to help you get the settings working better for where you are at.

 

[KimT]

Aaron, Re-read Laurie's explanation.

Oxygen and carbon dioxide are not separate. They are part of the air that goes in and out. The purpose of BiPap is so you can breathe as normally as possible. All the air in (so you can get oxygen) and all the air out (so you can expel carbon dioxide.). It doesn't pull oxygen in and expel CO2. It just helps your muscles breathe in and out. The pressure in the machine during an inhalation is stronger than the pressure during an exhalation so it's easier to breathe enough air in and the reduced pressure on exhalation allows air to move out easier.

 

[Aaronmandevill]

@KimT I gotcha, I think I understand it a bit better now. Naturally high pressure in oxygen pushed into lungs means it comes out easier. I only meant at the latest stages of this disease I heard c02 is the issue. My thought was to wonder if a device could do the exhalation work for us at that point. As far as I’m aware nothing exists and wonder if there just wasn’t a market for it or if the technology just wouldn’t work for some reason.

 

[affected]

No I think you are still a little confused.
The lungs absorb O2 from the air being pulled into the lungs. The lungs themselves are not impaired, the muscles that make them work like bellows are impaired. We don't push O2 in, just air.
The blood stream then deposits the unwanted CO2 into the lungs and the muscles push this out when we breathe out.

So in natural breathing it is not pushing air in and pulling it out, it is pulling air in and pushing it out.

The bipap assists with the dual pressure so that the mechanics of breathing is supported to the weak muscles, and this technology that works very well.

When the bipap no longer does the job well enough, a tracheostomy allows the breathing to happen purely by machine.

 

[Aaronmandevill]

@affected Thanks for the reply! I’m always so curious about science and how things work especially in reference to what’s happening with my body. I do know the limits of the questions I am able to handle the answers to. Because in the past I’ve asked questions I shouldn’t have and stressed myself out a lot.

Looking at respiratory onset prognosis is a good example of one I shouldn’t have looked up. Some things best left unknown.

Thanks again everyone for explaining some of the science behind the bipap and how it works with our lungs, super interesting!

 

[Bestfriends14]

Aaron, has your pulmonologist walked you through the mechanics of a bipap? I understand every doc is different, but when my husband got his, the pulmonologist and respirologist both spent a good deal of time with him explaining the nuances of bipap and the support it provides.

As PFT numbers are just numbers, and they don't tell the whole story as to how the patient is functioning, bipap settings that are correct for your functioning level, not just PFT score, is imperative. Without knowing the entire picture, settings that are incorrectly set can work in reverse and harm, not help. Have you had this indepth convo with your pulmonologist?

 

[Aaronmandevill]

@Bestfriends14

I will be having a very detailed conversation with the specialists at houston Methodist in 3 weeks. But for the time being I purchased my own BiPap to become familiar with it since my oxygen is already so bad. More than anything it’s a big piece of mind that I won’t have to go to the emergency room before the Houston appointment. The Air Force ordered me a BiPap but they are on 2 month back order.

You got me thinking though I was going to ask Air Force to redo my PFTs on Monday so maybe I can speak to their pulmonologist about it, thanks for idea!

 

[Bestfriends14]

Fiddling around with a bipap when you do not have a proper prescription in hand is not safe, nor recommended. I would meet with a pulmonologist before using any type of machine that aids in diaphragmatic functions.

My husband's PFT is at 15%, but his bipap settings are only slightly higher than entry level because he has a huge diaphragm. On the other hand, an ALS friend's PFT was at 41%, and he passed away from respiratory failure. So you see, bipaps are not a one size fits all.