Side effects of too much / too little Co2

[dsm]

I dug up some info for a thread started by James Skinner & thought it worth linking to as well as extracting 2 portions of that data here under its own more accurate title. The other thread = viewtopic/t39133/Mouth-Breathing-problem.html

I have been interested in PCo2 (Co2 measured in the blood) and its effects.


I have also wondered (just a little) if 'outasynch' (Bev), has been affected by CO2 imbalance when her Bipap Auto SV was set up in SV mode ?

This 1st extract is particularly interesting to me ...

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hyper-capnia = too much co2 in blood, hypo-capnia = too little.
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1.
EXTRACT : http://answers.google.com/answers/threadview?id=197162
1) Hypercapnia lowers the shivering threshold and increases core
cooling rate in humans. Along with eucapnic hypoxia, hypercapnia hence
has intense effects on human temperature regulation. Research work,
both current and past have been done on this subject. I have found
abstracts and mentions of such research here: .......




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2.
http://www.talkaboutsleep.com/sleep-dis ... ract23.htm

Summary:

Idiopathic Central Sleep Apnea Syndrome (ICSAS) is much less common than Obstructive Sleep Apnea (OSA) and less well understood. These apneas follow abrupt increases in breathing and reductions in arterial CO2, suggesting that they arise from hyperventilation. The authors have evidence that patients with ICSAS, compared to normal controls, show chronic hyperventilation and low blood CO2 both asleep and awake. Also the patients have increased sensitivity of receptors to blood oxygen and carbon dioxide, suggesting that this may underlie their hyperventilation. They authors propose that, in central sleep apneics, chronic hyperventilation keeps arterial CO2 close to the threshold for apnea, and acute episodes of hyperventilation drive it below this threshold, resulting in central apneas.

If this is true, raising the patients' blood CO2 and maintaining it above the threshold should prevent central apneas. They did this by having patients breathe a Co2-enriched gas or breathe through a face mask with added dead space during sleep to increase the amount of rebreathed CO2.

The authors studied six male patients, ages 54-71, with Idiopathic Central Sleep Apnea Syndrome, defined as apneas and hypopneas occurring at least 10 times per hour during sleep, of which at least 75% were central, along with at least two other symptoms of sleep apnea such as excessive daytime sleepiness or nocturnal choking.

All these patients received routine lab polysomnography, with added measurement of esophageal pressure during the first night to determine apnea type. Central apneas were defined by absence of breathing for at least 10 secs without esophageal pressure swings or thoracoabdominal movements to indicate respiratory effort. Central hypopneas were defined by a 50% or greater reduction in breathing under similar conditions.

Studies were conducted on four consecutive nights in the sleep lab. The first night, a control night, subjects breathed room air without a face mask. The second night, patients went to sleep wearing a face mask, at first breathing room air but once entering stage 2 non-REM sleep with the occurrence of central apneas, the Co2-enriched gas was given for 1 hour, after which room air and the enriched gas were alternated at 1-hr intervals for the rest of the night. The concentration of CO2 was gradually increased if apneas persisted. The third night, patients received an enriched gas mixture slightly higher than the threshold found the night before for suppressing apneas (1.5-2.3% vs. 1.0-2.0%). The fourth night, only four subjects agreed to breathe through a face mask with added dead space, increased gradually to increase the amount of rebreathed carbon dioxide.

The six subjects ranged in age from 54 to 71, averaging 60; in Body Mass Index from 223 to 37, averaging 29 (i.e., all were slightly overweight); in Apnea Hypopnea Index from 28 to 79/hr, averaging 44; in Movement Arousals from 17 to 29/hr, averaging 23. While awake, they had normal levels of blood oxygen (71-101, averaging 84) and mildly low blood carbon dioxide (35-38, ave. 36). While asleep, they had mild oxygen desaturation (minima 80% to 92%, average 86% and low carbon dioxide (37 to 43%, ave. 40%). Apneas and hypopneas occurred mostly in stage 2 sleep (80% of the time) in association with "periodic breathing," defined as at least three consecutive cycles of overbreathing alternating with central apnea or hypopnea. Reductions in carbon dioxide level always preceded central apneas. An apneic threshold was found to be 0.29% lower than baseline CO2; CO2 never fell lower than this without causing an apnea/hypopnea.

Inhaling CO2-enriched gas increased blood carbon dioxide and reduced its variability. This abolished periodic breathing and desaturations as well as central apneas and hypopneas. As a result, the proportion of time spent in stable breathing during stage 2 sleep was longer, significantly less fragmented than when breathing room air. These improvements were due entirely to reduction s in central apneas and hypopneas, not to obstructive apneas or hypopneas, which occurred mainly in REM sleep. Breathing through added dead space had similar effects on blood carbon dioxide and stabilization of breathing during sleep.

The authors found their results quite consistent with their initial theory, which had evolved out of related previous research. They had shown a therapeutic effect on sleep apneas of increased blood CO2. They noted that a similar measure had been used to relieve central apneas associated with neurological or cardiac diseases and after tracheostomy for obstructive sleep apnea, though these treatments were brief and documentation was minimal. The authors concluded that their findings with added CO2 and added dead space "point to their potential as treatments for this disorder. More studies over longer time periods will be required to test the therapeutic potential of these approaches."

[fuzzy96]

very interesting for a crazy man that jumps off buildings with perfectly good elevators, lmao.

but really i've quite wondered, since i was always warm but now that i starting cpap i can't hardly get warm enough to sleep. can it be that my ff doesn't flush enough co-2 out that i am rebreathing it ,thus elevated co-2 levels and messed up thermostat????

any ideas this may be the same thing?

[bdivine]

Its interesting how different aspect of your life can overlap. I teach Scuba Diving as well. For diving we are also concerned about both hyper and hypo-capnia. For most people, the breathing reflex is triggered by high levels of carbon dioxide in the blood (people with COPD, and other chronic lung problems sometimes switch to low levels of oxygen). Consistantly high levels of CO2 can cause not only the shivering, but also increased breath rates and headaches. Low levels will decrease the breath rates where if they are very low can cause some level of apnea. If they are too low, the apnea can last long enough to cause the 02 levels in the blood to decrease before the CO2 levels increase enough to trigger breathing.

Anyway enough of my rambling just thought I would add a bit.

Brian

[dsm]

very interesting for a crazy man that jumps off buildings with perfectly good elevators, lmao.

but really i've quite wondered, since i was always warm but now that i starting cpap i can't hardly get warm enough to sleep. can it be that my ff doesn't flush enough co-2 out that i am rebreathing it ,thus elevated co-2 levels and messed up thermostat????

any ideas this may be the same thing?

I guess this is always going to be a hard guess unless we were to have a CO2 measuring device and could regularly check co2 esp when these warm / cold bouts are happening. I know that Co2 meters are getting cheaper and will one day be practical to buy for home use. I don't quite know how they work whereas the way SpO2 probes work is pretty well documented.

For me it is a daily thing that I drape a wool pullover over my back & esp so on hot days but typically most types of day, if I don't, then any exertion will typically cause me to sweat & I then get cooled & end up with a chill or get a cold or just feel very uncomfortable. I had never even though of connect that to CO2 levels until reading this items yesterday. It may be unrelated but it looks like it could have some significance.

In your case, I gather you are saying that since going on cpap you are now feeling colder than you used to (in similar circumstances ? - same temperature in the room ?).

DSM

[dsm]

Its interesting how different aspect of your life can overlap. I teach Scuba Diving as well. For diving we are also concerned about both hyper and hypo-capnia. For most people, the breathing reflex is triggered by high levels of carbon dioxide in the blood (people with COPD, and other chronic lung problems sometimes switch to low levels of oxygen). Consistantly high levels of CO2 can cause not only the shivering, but also increased breath rates and headaches. Low levels will decrease the breath rates where if they are very low can cause some level of apnea. If they are too low, the apnea can last long enough to cause the 02 levels in the blood to decrease before the CO2 levels increase enough to trigger breathing.

Anyway enough of my rambling just thought I would add a bit.

Brian

Brian,

I would imagine that scuba instructing means you have to have a particularly good understanding of breathing & the gasses involved. In my 20s I used a 72CU tank & used to dive off the coast of Sydney. Back then we had little regulation - used to dive alone in waters known for sharks - my brother & I used to chase them. Also in those days we had spear guns & 'power heads' (cartridge in a firing mechanism at the end of a hand spear).

I don't recall ever learning then about O2 & Co2 levels. Funny to be finding out now.

Some interesting comments re this juggling act in addition to the point you made (o2 level going down before co2 triggers faster breathing), include
the chilling effect, that co2 hyperventilation also can cause too much oxygen to be absorbed, and that if patients are put on too much oxygen, that triggers an imbalance in co2 & that too much co2 causes 'acidosis in the blood' and too little co2 cause the blood to go dangerously alkaline.

Sooo many side effects.

DSM

[OutaSync]

DSM,

Would that have anything to do with my waking up three or four times a night just before I get the feeling that an internal furnace has been turned on? This is not a menopause thing, I've woken up soaked with sweat all of my life. Since XPAP, I've woken up just before it hits and am able to throw off the covers. My BPM and Peak Flow rates are all over the place. Even though I have great AHI numbers, I still wake up a lot and have never felt like I've gotten a good night's sleep. I don't know what it feels like to wake up "refreshed". I do feel as though I can think better than I could last fall, so I know the SV is helping more than the Auto ever did.

Bev

[Linus]

It is the CO2 level that the body looks for when regulating breathing. CO2 changes the pH of blood which triggers the breathing response.

A good example of this was pointed out at NASA in the 1960's. They used pure nitrogen environments for rocket stages to prevent fire. Someone walked into the pure nitrogen environment and collapsed after a few minutes. Later another person went after that person and collapsed. Both died without realizing what happened. It took others with an oxygen supply to recover the victims. It was a terrible accident. What happened is the person exhaled CO2 and inhaled pure nitrogen. The Nitrogen was not absorbed. The next exhale released more CO2 until the body's level was so low on CO2 that breathing stopped. The Oxygen starvation caused Hypoxia and resulted in death. Fortunately the victims were not subject to the terrible breathing reflex that results in an elevated CO2 level.

There is a growing trend for respiration specialists to measure CO2 levels along with SPO2. I came across some study material on Philips web site a while back on this.

[dsm]

It is the CO2 level that the body looks for when regulating breathing. CO2 changes the pH of blood which triggers the breathing response.

A good example of this was pointed out at NASA in the 1960's. They used pure nitrogen environments for rocket stages to prevent fire. Someone walked into the pure nitrogen environment and collapsed after a few minutes. Later another person went after that person and collapsed. Both died without realizing what happened. It took others with an oxygen supply to recover the victims. It was a terrible accident. What happened is the person exhaled CO2 and inhaled pure nitrogen. The Nitrogen was not absorbed. The next exhale released more CO2 until the body's level was so low on CO2 that breathing stopped. The Oxygen starvation caused Hypoxia and resulted in death. Fortunately the victims were not subject to the terrible breathing reflex that results in an elevated CO2 level.

There is a growing trend for respiration specialists to measure CO2 levels along with SPO2. I came across some study material on Philips web site a while back on this.

I am leaning towards getting a Co2 recorder just to get a feel for what they do & report. Am still sure that some of us (incl you Bev) may be seeing side effects of Co2 imbalance. But I am relying on guesswork rather than any expertise.

DSM

[Linus]

People with Oxygen concentrators and oxygen bottles should use care with the flow rate. Too high of a flow can affect CO2 levels, which can result in slowed breathing.

[dsm]

People with Oxygen concentrators and oxygen bottles should use care with the flow rate. Too high of a flow can affect CO2 levels, which can result in slowed breathing.

I have got my hands on an O2 concentrator & was going to do some tests with it - bleed in a very small amount of O2 & monitor several nights SpO2 & look to see the differences. Am very aware of the problems of too much O2 & your point is very well taken.

My prediction is it will have little to no effect on myself (short of too much O2 which would have the discussed side effects). I am expecting no impact on my AHI or well being but am anticipating I can lift the average SpO2 reading I get, from around 95-96 to 97-98. From what I have learned 99 is on the high side & that 98 is quite a good SpO2 sat.

DSM

[dsm]

DSM,

Would that have anything to do with my waking up three or four times a night just before I get the feeling that an internal furnace has been turned on? This is not a menopause thing, I've woken up soaked with sweat all of my life. Since XPAP, I've woken up just before it hits and am able to throw off the covers. My BPM and Peak Flow rates are all over the place. Even though I have great AHI numbers, I still wake up a lot and have never felt like I've gotten a good night's sleep. I don't know what it feels like to wake up "refreshed". I do feel as though I can think better than I could last fall, so I know the SV is helping more than the Auto ever did.

Bev

Bev,
I never believed we got to the root cause of your VB when running your SV in SV mode. Co2 imbalance crossed my mind as a possibility but I know far too little about the overall effects of CO2 imbalance to be confident it was a cause.

What made me wonder was the constant (but erratic) fluctuation in your breaths per minute, one period very fast (like flushing out co2) then slow (like letting it build up again). I am pretty sure your charts did show a significantly fluctuating breathing rate when in SV mode).

Doug

[dllfo]

Interesting topic ....
Bev, be aware, some people can have their oxygen levels reduced down as low as 15% and not really know it. The National Jewish Hospital ran my oxygen level down to 18% and I did not know it. I was still talking to the medical staff until the alarms went off. My only indication was that my chest felt very warm. Personally, if it were my family and their oxygen levels were found to be below 88% without them knowing it, I would have a competent Pulmonologist test them. I have too many breathing problems to list, but the scary one is CCHS. When I go to sleep my brain/CNS does not always tell me to breathe. I have slept with the SV since around Sept 2007. BTW, my Service Dog/Medic Alert Dog is credited with saving my life more than once.

Heat and the SV. I can get cold at night, while on the SV, but as soon as I turn it off, my furnace goes wide open and I throw the covers off. Same at night, I am hot and don't want the covers. Put the mask on, turn the SV on and I cool right off. My wife can't figure out how I can do that, maybe we know now??? During the day I run hot, but pile covers on at night. Interesting.

I flew in the Air Force and am still certified PADI, so your conversation is of great interest. And no, I don't dive anymore.

[wlenz]

Very interesting topic. I occassionly wake in the middle of the night either shivering, or so hot I throw the covers off. This thread gives me some new food for thought. Thanks to everyone that added to this thread.

[Linus]

DSM,
You and I are much alike. You like equipment. I was thinking of getting an oxygen concentrator as well - for experimentation. The O2 bars use them with a lowered level of O2 by mixing it with ambient air. I was thinking of using oxygen for workouts on a stationery bike.

Avionics Oxygen sometimes is nice when you have a headache.
--Linus

[OutaSync]

Dilfo,

Can you post one of your charts? I would be interested in comparing. I realize that you have some major health issues. It's just that there are so few of us who use the SV.

Bev