Hypercapnia symptoms vs Hypoxemia any way to tell at home?

Hi,

Is there any way to differentiate low blood oxygen from high blood CO2 based on symptoms or any "at home" measurement devices? Using CPAP now at low setting for mixed sleep apnea. I also use a finger pulse oximeter that records on occasion at night. Noticed I've been fighting machine more and when I don't use it I no longer snore but get alarms on finger pulse oximeter showing blood oxygen 80 percent (alarm goes off and wakes me up). CPAP already at a very low setting. Would like to figure out if I'm not breathing deeply enough to cycle air causing CO2 build up from home or get some feedback before re-engaging sleep doctor. I don't do well with sleep studies, often not falling asleep..

Thanks.

ilmdc wrote:Hi,

Is there any way to differentiate low blood oxygen from high blood CO2 based on symptoms or any "at home" measurement devices? Using CPAP now at low setting for mixed sleep apnea. I also use a finger pulse oximeter that records on occasion at night. Noticed I've been fighting machine more and when I don't use it I no longer snore but get alarms on finger pulse oximeter showing blood oxygen 80 percent (alarm goes off and wakes me up). CPAP already at a very low setting. Would like to figure out if I'm not breathing deeply enough to cycle air causing CO2 build up from home or get some feedback before re-engaging sleep doctor. I don't do well with sleep studies, often not falling asleep..

Thanks.

No. It would require blood tests. Higher levels of CO2 in the blood can be caused by any number of things......like COPD or taking antacid tablets. Do some Googling and reading.

You didn't mention your settings, but maybe there could be a "compromise" in the pressure settings.

Have you been prescribed additional oxygen? Or, have you asked about it?


Den

.

ilmdc wrote:Hi,

Is there any way to differentiate low blood oxygen from high blood CO2 based on symptoms or any "at home" measurement devices? Using CPAP now at low setting for mixed sleep apnea. I also use a finger pulse oximeter that records on occasion at night. Noticed I've been fighting machine more and when I don't use it I no longer snore but get alarms on finger pulse oximeter showing blood oxygen 80 percent (alarm goes off and wakes me up). CPAP already at a very low setting. Would like to figure out if I'm not breathing deeply enough to cycle air causing CO2 build up from home or get some feedback before re-engaging sleep doctor. I don't do well with sleep studies, often not falling asleep..

Thanks.

Funny you should ask - I work in a university hospital physiology/tech lab and dragged home a bunch of monitoring equipment, the results of which are laid out in nauseating detail in my first thread.

I would expect that there are no normal "at home" devices that monitor CO2. What is usually done in a hospital is to monitor the concentration of CO2 in exhaled air (so-called 'end tidal') - this gas is near equilibrium with the blood passing through your lungs, so it is like a non-invasive blood-gas test. It is possible to measure O2 and CO2 directly from a blood sample, but the relevant values are for *arterial* gases and arterial sampling is messy/risky/painful (unlike the more common venous blood sampling) and also requires a specialized analyzer. The lab-grade capnometers (CO2 meters) we use cost thousands of dollars and are bulky and somewhat fragile - they also require regular calibration using reference gases from a standards lab. The technology for O2 sat is much more robust (and cheap) and readily available for use in home, sports, etc.

What I can tell you (in general physiology terms) is that if your O2 saturation is at 80% due to apnea, then you are almost definitely hypercapnic (high CO2). Gas exchange is gas exchange, and if you're not getting O2 onto hemoglobin (what the O2 sat tells) then you are also not unloading CO2 from your blood.

In my improvised/borrowed home rig, I was recording finger O2 sat, expired O2, expired CO2, and diaphragm movement. It was interesting to see the link between the parameters for a few nights, but in the end everything other than O2 sat and diaphragm movement was a bit redundant. I will say it was striking to see the CO2 go around 10 mmHg above my normal resting value (this happened along with SaO2 values in the low 80s). This would generally be very uncomfortable in an awake person, especially during a forced breath-hold. One can assume that this alone (hypercapnia during apnea) should be sufficient to yield a big jolt of cortisol even if asleep. I was waking up in the morning with my body feeling like it was on fire, which I suspect was due to the nightlong bath in stress hormones. I have a skin conductance probe somewhere and would be interesting to look at this and other autonomic stress markers but I haven't got round to it.

I would not normally be worried about CO2 accumulation in a normally sized room - I've done some calculations on that and unless your room is coffin-sized and has no ventilation this should be negligible compared to the CO2 buildup you get from your own metabolism during an apnea event. Rebreathing air from some types of respiratory circuit can, however, very quickly build up CO2 (e.g. breathing in and out through a long closed tube for enough time could get intense). I'm not an expert in CPAP machines but I would assume (and it looks like) they are designed to avoid rebreathing at all costs (indeed the whole idea of positive air pressure would preclude rebreathing, unless perhaps you've put the intake right next to your spouses mouth). Pulling the blanket over your head leads to a certain amount of rebreathing, and the 'stale air' feeling you get is basically hypercapnia (don't do this after you or your spouse have eaten beans).

Disclaimer: I am not a doctor or any kind of healthcare professional. Just a guy who claims to work in research. Information offered here is for educational purposes - ask your doctor about any and all health concerns.

Thanks for this info. I use a ResMed S9 Elite set at 6 with the EPR at max (which I think gives me an exhale pressure of 4?). I don't use oxygen.

I'm 37, never smoked, and have no diagnosis of COPD, etc. I use the SleepyHead app to read my data card as I like to try and understand my daytime fatigue, etc compared to my past sleep and had noticed the medium Tidal Volume calculation it gives after use is 280-300, which I think is on the low side (I know this is not scientific / clinical). I was diagnosed with a cervical radiculopathy last year. Told to follow up if "bad stuff" symptoms happens (degenerative diseases, etc). I'm following up with my sleep doctor first as he is easier to get into and I think I need a change of equipment or something. Was curious if chronic high CO2 in blood would be a more natural cause of spine issues (bone decalcification) vs having to go through another round of expensive, stressful and time consuming neurology tests.


Thanks.

One additional item. About a year ago I did a few exercise bike tests where they hook you up to a breathing machine (sorry don't know medical name of it) to measure CO2 and lots of other stuff as part of a CFS test. In all cases for the first 5 min or so, my "respiratory quotient" was sky high. Doctor said it's not a level seen in people alive (think he was joking). He had tech recalibrate machine, and had same result. Why I was thinking again about chronic high blood CO2 causing issues and wanted to discuss as talking to a doctor about self-diagnosed or suspected things is tricky in my opinion.

Thanks.

leptic wrote:

ilmdc wrote:Hi,

Is there any way to differentiate low blood oxygen from high blood CO2 based on symptoms or any "at home" measurement devices? Using CPAP now at low setting for mixed sleep apnea. I also use a finger pulse oximeter that records on occasion at night. Noticed I've been fighting machine more and when I don't use it I no longer snore but get alarms on finger pulse oximeter showing blood oxygen 80 percent (alarm goes off and wakes me up). CPAP already at a very low setting. Would like to figure out if I'm not breathing deeply enough to cycle air causing CO2 build up from home or get some feedback before re-engaging sleep doctor. I don't do well with sleep studies, often not falling asleep..

Thanks.

Funny you should ask - I work in a university hospital physiology/tech lab and dragged home a bunch of monitoring equipment, the results of which are laid out in nauseating detail in my first thread.

I would expect that there are no normal "at home" devices that monitor CO2. What is usually done in a hospital is to monitor the concentration of CO2 in exhaled air (so-called 'end tidal') - this gas is near equilibrium with the blood passing through your lungs, so it is like a non-invasive blood-gas test. It is possible to measure O2 and CO2 directly from a blood sample, but the relevant values are for *arterial* gases and arterial sampling is messy/risky/painful (unlike the more common venous blood sampling) and also requires a specialized analyzer. The lab-grade capnometers (CO2 meters) we use cost thousands of dollars and are bulky and somewhat fragile - they also require regular calibration using reference gases from a standards lab. The technology for O2 sat is much more robust (and cheap) and readily available for use in home, sports, etc.

What I can tell you (in general physiology terms) is that if your O2 saturation is at 80% due to apnea, then you are almost definitely hypercapnic (high CO2). Gas exchange is gas exchange, and if you're not getting O2 onto hemoglobin (what the O2 sat tells) then you are also not unloading CO2 from your blood.

In my improvised/borrowed home rig, I was recording finger O2 sat, expired O2, expired CO2, and diaphragm movement. It was interesting to see the link between the parameters for a few nights, but in the end everything other than O2 sat and diaphragm movement was a bit redundant. I will say it was striking to see the CO2 go around 10 mmHg above my normal resting value (this happened along with SaO2 values in the low 80s). This would generally be very uncomfortable in an awake person, especially during a forced breath-hold. One can assume that this alone (hypercapnia during apnea) should be sufficient to yield a big jolt of cortisol even if asleep. I was waking up in the morning with my body feeling like it was on fire, which I suspect was due to the nightlong bath in stress hormones. I have a skin conductance probe somewhere and would be interesting to look at this and other autonomic stress markers but I haven't got round to it.

I would not normally be worried about CO2 accumulation in a normally sized room - I've done some calculations on that and unless your room is coffin-sized and has no ventilation this should be negligible compared to the CO2 buildup you get from your own metabolism during an apnea event. Rebreathing air from some types of respiratory circuit can, however, very quickly build up CO2 (e.g. breathing in and out through a long closed tube for enough time could get intense). I'm not an expert in CPAP machines but I would assume (and it looks like) they are designed to avoid rebreathing at all costs (indeed the whole idea of positive air pressure would preclude rebreathing, unless perhaps you've put the intake right next to your spouses mouth). Pulling the blanket over your head leads to a certain amount of rebreathing, and the 'stale air' feeling you get is basically hypercapnia (don't do this after you or your spouse have eaten beans).

Disclaimer: I am not a doctor or any kind of healthcare professional. Just a guy who claims to work in research. Information offered here is for educational purposes - ask your doctor about any and all health concerns.

Good in depth analysis... I had to read it twice and look up some terms but it was worth it. Whew, human physiology is complicated.

As a side note: Your avatar is interesting but not very well oriented towards peaceful sleep It's the classic 1781 'Nightmare' painting by Henry Fuseli:
https://en.wikipedia.org/wiki/The_Nightmare

Wulfman... wrote:No. It would require blood tests. .

actually, no, there are now non-invasive blood c02 meters, though they're certainly not ubiquitous like the oximeters are.

palerider wrote:

Wulfman... wrote:No. It would require blood tests. .

actually, no, there are now non-invasive blood c02 meters, though they're certainly not ubiquitous like the oximeters are.

Could very well be. Lots of advancements in testing things. It's been a couple of years since I did much searching or reading on this subject.

Anyway, here's a link to a Google search I just did in case the OP is interested.

https://www.google.com/search?q=Causes+ ... 8&oe=utf-8


Den

.

Hi,

I don't have any of the common causes of Hypercapnia. My reason for asking this forum was due to a past daytime exertion test which was initially abnormal as well as symptoms and things this causes that might fit me. From google searches, the test for this in somewhat invasive during sleep with regards to blood and the fact I've never had my C02 measured when I did a sleep study (I think)..

Normal blood work I get for unrelated issues always has my serum C02 at 1 below the flag, at the high mark or occasionally one above with doctors not really saying its anything to worry about.

Thanks.

Wulfman... wrote:

palerider wrote:

Wulfman... wrote:No. It would require blood tests. .

actually, no, there are now non-invasive blood c02 meters, though they're certainly not ubiquitous like the oximeters are.

Could very well be. Lots of advancements in testing things. It's been a couple of years since I did much searching or reading on this subject.

Anyway, here's a link to a Google search I just did in case the OP is interested.

https://www.google.com/search?q=Causes+ ... 8&oe=utf-8


Den

.

- Somewhat new with forum, posting reply below quote in future.

You had a test. The doctor was there. He did NOT check you into the hospital.
Please think about that. You are probably OK.
If you are having trouble breathing, go to the ER.
Otherwise, relax.

chunkyfrog wrote:You had a test. The doctor was there. He did NOT check you into the hospital.
Please think about that. You are probably OK.
If you are having trouble breathing, go to the ER.
Otherwise, relax.

I had a test two years ago. I've been using CPAP since then. I am attempting to do more than google by asking others who may have more information than I do prior to seeing a doctor I normally see to optimize that visit. If there is a professional forum to address layperson questions to healthcare professionals without the expectation of anxiety or liability, that would be great. I'm not here for that, just information I was not able to find via google based on my situation.


Thanks.

ilmdc, with the WATCH- PAT 200 you can diagnose SLEEP APNEA without the need of invasive samplings of blood and gases:


http://ppdsleep.com/2013/11/15/testing-portable/

http://www.sleepworksmedical.com/diagno ... -overview/

Wulfman... wrote:

palerider wrote:

Wulfman... wrote:No. It would require blood tests. .

actually, no, there are now non-invasive blood c02 meters, though they're certainly not ubiquitous like the oximeters are.

Could very well be.

just google "Transcutaneous co2 monitor"

palerider wrote:

Wulfman... wrote:No. It would require blood tests. .

actually, no, there are now non-invasive blood c02 meters, though they're certainly not ubiquitous like the oximeters are.

We looked into these a few years ago at the lab - for some reason, the anesthesiologists dismissed them as 'probably not reliable'. Should look into it again as perhaps the technology has advanced or the docs figured they had access to expired gases anyway (the example of this for sleep studies is evident) - I wonder what the physical principle is for the transcutaneous, and what units the results are in? End-tidal CO2 analyzers use IR absorption - this is easy when the CO2 is mixed with O2/N2; not sure how it works when probing through skin and mixed with blood (argh - will now have to look this up; should be sleeping!)

There's a slide deck on the topic here. Looks slightly like a doc doing a paid presentation for radiometer, but they do cite a number of groups using this.

leptic wrote:

palerider wrote:

Wulfman... wrote:No. It would require blood tests. .

actually, no, there are now non-invasive blood c02 meters, though they're certainly not ubiquitous like the oximeters are.

We looked into these a few years ago at the lab - for some reason, the anesthesiologists dismissed them as 'probably not reliable'. Should look into it again as perhaps the technology has advanced or the docs figured they had access to expired gases anyway (the example of this for sleep studies is evident) - I wonder what the physical principle is for the transcutaneous, and what units the results are in? End-tidal CO2 analyzers use IR absorption - this is easy when the CO2 is mixed with O2/N2; not sure how it works when probing through skin and mixed with blood (argh - will now have to look this up; should be sleeping!)

There's a slide deck on the topic here. Looks slightly like a doc doing a paid presentation for radiometer, but they do cite a number of groups using this.

there's quite a number of products on the market, most are in the 'not cheap' range

this might be informative: http://www.medscape.com/viewarticle/444326