PERILS OF O2 INFUSION INTO CPAP LINE?

[torontoCPAPguy]

Just back from my sleep Doc. Seems like a nice guy and very well educated. Here is what he said:
1. Looked at my output from the Resmed S9 Autoset and the CMS50E oximeter (graphs) and commended me on both my knowledge of my issues and on taking the effort to obtain the data. With the new once-a-year sleep study rule in all of Ontario, he is going to be recommending data producing APAP blowers to all of his patients henceforth and providing the necessary paperwork where possible so that they are paid for by insurance.

2. Advised me that my problem was not entirely related to OSA... but obviously related to hypopneas and shallow breathing causing my SaO2 to plummet. It was obvious from the graphs and data presented.

3. SAID HE WAS SADLY DISAPPOINTED AT THE REACTION TIME OF THE RESMED S9 AUTO TO HYPOPNEA EVENTS AND THAT IT WAS NOT PICKING UP ON ALL OF THE HYPOPNEA EVENTS - SUGGESTED IT WAS A MORE CRUDE TOOL THAN WHAT IS USED IN THE LAB SETTING AND POINTED OUT THAT IT DID NOT HAVE THE BENEFIT OF AN EEG TO ADD DATA.

4. SUGGESTED THAT MY CONCLUSION THAT O2 INFUSION INTO MY CPAP LINE WAS LIKELY GOING TO BE MY MAGIC BULLET WAS QUITE POSSIBLE AND LIKELY CORRECT BUT WANTED A PULMONOLOGIST TO CONFIRM AS IT WAS NOT HIS EXPERTISE. I HAVE AN APPOINTMENT IN THREE WEEKS (THAT'S AMAZING AS THE WAIT TIMES TO SEE A SPECIALIST IN ONTARIO CAN RUN SIX MONTHS PLUS).

5. STATED THAT IN REM SLEEP THE BODY IS ESSENTIALLY PARALYZED... THE BRAIN HAS SHUT DOWN AS MUCH AS POSSIBLE. THE ONLY MUSCLES THAT CONTINUE 'ON AUTOMATIC' ARE THE DIAGHRAM AND THE EYES ESSENTIALLY AND THE BREATHING IS NOW BEING DRIVEN BY THE LEVELS OF CO2 AND O2 WHICH CAN BE MASKED BY O2 INFUSION - HE WANTED A PULMONOLOGIST TO CONSULT AND ADVISE ME AS TO THE LEVEL OF O2 INFUSION THAT WOULD BE APPROPRIATE.

So, the bottom line? SaO2 desaturations can and will occur for a variety of reasons and DO (I repeat for effect "DO!") have an effect on quality of sleep and can be dealt with in a variety of ways. He asked me to crank UP my pressures by about 25%, which I have done and will see if there is any effect. It is doubtful. And he is arranging for a pulmonologist to consult and ensure that O2 infusion is indeed indicated and to what extent.

For the record, I educated myself with the help of GOOD friends on this forum and to the extent that it was I who determined that supplemental O2 at night was an indicated solution... I now have agreement from an MD specializing in sleep issues, who has some 25 years of experience. And once the O2 is being infused and I am showing higher and steadier levels of O2 at night he is going to wangle me into a full sleep study once again (regardless of what the regulations now say) as this is 'out of the box'. I can hardly wait.

My desaturations, as a matter of interest, ALL occur during REM sleep during my sleep studies and with CPAP/APAP are significantly improved (they were actually down in the 50% range before CPAP).

So there you have it.

Comments on O2 infusion?

[harry33]

re the body being paralysed, its possible to wake up and be unable to move, the brain ia awake and the body still asleep

[Gerald]

I suspect you already know more about the situation than the doctors do. Why not fire that thing up......and partake of 1-liter per min....just to see what happens. That amount is so little that I can't see how it could do any damage. Checking your desats with your oximeter will let you know if you're making progress.....and if you sneak up on it for the next three weeks....gathering data every night....you'll know so much that the pulminologist won't be able to lead you down the wrong path.

[billbolton]

3. SAID HE WAS SADLY DISAPPOINTED AT THE REACTION TIME OF THE RESMED S9 AUTO TO HYPOPNEA EVENTS AND THAT IT WAS NOT PICKING UP ON ALL OF THE HYPOPNEA EVENTS - SUGGESTED IT WAS A MORE CRUDE TOOL THAN WHAT IS USED IN THE LAB SETTING AND POINTED OUT THAT IT DID NOT HAVE THE BENEFIT OF AN EEG TO ADD DATA.

You may want to find a new sleep clinician who actually has a realistic understanding of what any xPAP treatment device is capable of!

Cheers,

Bill

[Muse-Inc]

Fascinating...keep us posted.

[torontoCPAPguy]

gvz: You have outdone yourself. For any tekkie this is a beautiful system and I only wish that the idea was not already patented. Sic. I am NOT going to wait to see the pulmonologist but am going to go ahead with infusion of O2 at 2-3L into my airflow as soon as my oxygen concentrator arrives.

BY THE WAY... I have been reading over the ResMed websites and all they seem to have to say about oxygen infusion is the usual safety stuff and there is a one liner somewhere where they caution against using more the 4L/M infusion rate. I'm going to have to find that again and post it for you.

Unfortunately, I am not quite as tekkie as you are or I would have the same setup going. That flow valve is indeed a bit expensive but all good gear is, as we know, unless it is made in China (and I just might have a look-see).

Again, congrats on putting it all together - my sleep doc commended me on gathering all of the information; has set up the fastest meeting with a pulmonologist pro (an MD and a PhD) and is promising to get me into another sleep study WITH O2 infusion to see the difference in REM sleep on their EKG in addition to the data already being collected (i.e. especially SaO2).

He has cranked my APAP up to 12/14 - 20 cmH2O to see the effect over the next week on my SaO2 and last night I hovered in the 95% range except for two plummets; one to about 80% and the other right off the bottom of the chart, below 70%.

Not feeling too bad today but the magic bullet has not been attained quite yet.

Regards

[torontoCPAPguy]

Going to bed now with my oximeter on and my SD RAMCARD at the ready in my S9 Auto. Going to set up the other S9 Auto tomorrow to see if they read the same. And am very excited as I now have appointment with a good pulmonologist and my oxygen concentrator is already enroute!

Sure hope I don't have a battle with the pulmonologist about this.... the sleep doc has a concern about the balance between the benefit of oxygen infusion and the possible detrimental effects of suppressing CO2 and CO levels that cause the body to breathe during REM sleep (?).

For my part I intend to infuse 2-3L/M as soon as the concentrator arrives regardless; when I was in hospital they fed me up to 5L/M PURE oxygen without worrying too much about what was going on while I was sleeping - and in an effort at machismo, it was me, not them, that hung up the oxygen canulas at 3L/M as they were a bother. Put them on only once or twice when I felt short of breath during the following weeks at night and am not sure if that was due to anxiety or shortness of breath. Being intubated for three weeks tends to give one cause to pause and think... I still get the heeebie-jeeeebies when I think back to last summer. And I thank God that I am around to tell the tale. I was code blue twice and never knew it... I was in lala land.

[torontoCPAPguy]

Outstanding!
So here,s the big question. Did you feel any different this morning?

I have absolutely no doubt whatsoever that my autonomic nervous system, which enables me to breathe while my body is paralyzed during REM sleep (excepting the diaghram and eyes) is reacting to SOMETHING... my question now is: does it react to SaO2 levels directly? Does it react to blood pressure climbing? Or does it react to CO2/CO levels in the bloodstream that trigger the breathing 'reflex'? Interesting, huh?

One thing is for sure and that is if one can maintain an SaO2 in the 95% range all night, including during L4 and REM sleep, the body's autonomic nervous system does NOT tend to attempt to arouse one from sleep in order to 'unfreeze' the human machine and permit or encourage deeper breathing. Is this, then, like a dog chasing its tail? CO2/CO levels stimulate the breathing reflex while in REM to get one to 95%? But without that reflex infused O2 in small quantities does essentially the same thing during shallow breathing (e.g. brings the body's SaO2 up to where the body wants it to be which appears to be the 95 - 100% range). An interesting 'discovery' here. And it leads to MORE questions, all of which I am noting in order to make the pulmonologist nuts when I see her (She is an MD/PhD). Does the make/model of the mask that one is using have an effect (adverse or otherwise) on the body's ability to regulate its SaO2? In other words, as we all know, our masks have vents that are supposed to eliminate or reduce the levels of CO2/CO in the air we are breathing.... what happens if the air vents get blocked by a blanket or pillow? Etc.

[Majormanager]

Dear torontocpapguy,

I love the concept of you oxygen saturation/titration feedback system. You probably know this, but oxygen prescriptions for home oxygen are written based on l/m, or liters per minute of flow rate. Clinically such flows crudely equate to an "fio2" expressed in percent. Using a nasal cannula for example, a rule of thumb presupposes an fio2 of about 24 percent. Room air as you probably know is 21 percent, so 1l/m is a somewhat small supplemental dose for an adult, but may make a huge improvement in one's o2 sat if reduced due to hypoventilation.
As a long time respiratory therapist who spent numerous years in home care assisting home oxygen patients on cpap, commonly used best practise was to titrate a constant flow of concentrator oxygen into the cpap circuit, close to the machine, while using an in-line oxygen analyzer to measure the fio2. This simple, yet practical method may be useful in your situation as well, and such prescribed fio2 can be also determined in the sleep lab.

[frh]

gvz, I too have been reading this with interest. Like toronto I am in awe of what you were able to build. Please forgive my dumb assumptions, but when looking at the pictures and description I started wondering if shutting-off the flow of O2 would harm the oxygen concentrator? My understanding is they are designed to run all the time without a lot of restriction. (Or is that what the input / output loop is for?)

I am probably trying to compare apples to oranges, but a decade ago I bought a 12 volt electrically controlled pneumatic directional control solenoid valve for a project. I remember it being pretty cheap (closer to $100 than $1,200). What I had was similar to what this pdf describes: http://www.omega.com/auto/pdf/SimpValvesguide.pdf.)

It taxed my brain figuring out how to use a remote car starter make a double acting air cylinder throw a lever back and forth. It seems like it would be relatively easy to use the same valve I had to divert O2 from a concentrator into the CPAP machine, or just dump it into the room without restricting the flow. It's hard for me to imagine how you got the computer to control the thing you built.

My recent appointment with the sleep doc did not go as well as toronto's. As far as the RT and the doc were concerned the titration was successful. Since the turbinate reduction surgery, I don't need as much pressure (it's down from 6 to 5). According to the doc, my sleep study indicates I do not need supplemental O2. The sleep doc (a neurologist) told me I will have to convince a pulmonologist or my GP to give me a prescription if I want supplemental O2 at night.

In spite of getting almost as much sleep as I usually get at home, I came very close to falling asleep at the wheel on the way home. I took a 2-1/2 hour nap as soon as I got home, and the rest of the day was one of the worst I have had since being on CPAP. (Total lack of mental and physical energy, no short-term memory, etc.) I have no idea why, but I have a bad day every time I don't bleed O2 into the CPAP hose when I sleep.

Fortunately the hospital documented my need for O2 the night after my turbinate reduction surgery. The admission nurse had no problem ordering 2-1/2 liters of O2 for my 4 day hospital stay after nissen fundoplication surgery last week.

Other than watch the TV or the oximeter display, there wasn't much else to do. I found it very interesting to see my SO2 levels fluctuate throughout the day. Even though there is nothing wrong with my lung capacity, etc., my sO2 level frequently fell below 90 whenever I took off the nasal canula. (And that was just laying in bed or sitting in a chair.) When I was wearing the nasal canula, it never fell below 93. On the other hand, they had me pretty hopped-up on dilaudid through the IV for the first 3 days after the surgery. (That had to make a huge difference.)

And that makes me wonder gvz, if you have tried wearing the oximeter as you go about your daily routine?

[LoQ]

I got an O2 concentrator, a gas flow controller that specifically works for oxygen, a wireless oximeter module, and a silent laptop PC to control it all. I made the software to automatically enable/disable the flow of oxygen based upon the realtime feedback from the oximeter using the serial port communication capability of the Contec CMS 50F. At the moment it turns on the flow of O2 when my saturation dips below 93 and then stops the flow when it is above 95.

This is a very interesting post with some really nice pictures. I think you deserve a Lab Rat Award, but I'll leave that to Rested Gal.

I have one comment and several questions. My one comment is a suggestion that you might implement a rule in the software to leave the oxygen on for a period (like an hour) once you experience a desat. In looking at my oximeter data, I notice that all of my desats occur during REM, and that once a desat occurs, I'm going to have more oxygen issues for the rest of REM, which is typically 45 minutes to an hour before my breathing settles back down. I notice that my AHI events are grouped the same way for about the same period of time, by the way. If you are desatting during REM, it might be smart to leave the oxygen on (with increases allowed during the time) so that you are not responding so much to delayed information as you get from the oximeter. The oximeter data is coming a little too late, but you can short-circuit that by using the oximeter data to predict REM onset. If your desats are not bunched, then this is probably not going to work.


Here are a few of my questions about your really magnificient setup.

* Why do you have two oxygen generators?

* How did you acquire the oxygen generators? (You may wish to PM me on this one.) I don't know how to tell if a used one is any good, and I'm reluctant to buy something that may be worthless.

* Can you say something more about how the Input/Output O2 Loop with Micron filters works?

* The flow controller doesn't look like it has any oxygen tubing to it, or is that oxygen tubing connecting to the right and the left? Those connections look like gold (metal) electrical connections, but my eyes are not very good.

* I want one of those chili pads. Do you like it? Have you had it through a cold season, assuming it gets cold in the winter where you live?

[torontoCPAPguy]

I really don't know where you find the time, but I would get hold of the patent holder and offer a deal as they are obviously not doing so; in addition, I might want to take a real close look at that patent. It is one thing to have an idea; and an entirely seperate thing to produce a working prototype that does what the patent suggests. And my understanding is that there is a time limit; it is a combination of the date the idea is filed and the date the working prototype is presented to the public. Again, kudos to you for diving in with both feet. Outstanding job. I am thinking that when my concentrator arrives I am going to make an effort to put the same thing together here. As far as I am concerned, from a physiology point of view, this solution to a very special issue (that of desats that cannot be corrected in any other way... yet allowing the autonomic nervous system to perform to its maximum during L4 and REM sleep by not overdosing and masking CO2/CO in the bloodstream which reduces efficacy of the signal to 'breathe') is outstanding for folks in our position, where there are desats in SaO2 from time to time during sleep, especially L4 and REM sleep, but they are not necessarily caused by OSA directly related causes. In my case, as you know, it is L4 and especially REM sleep that triggers my problem with desats... but the problems are compounded heavily by the fact that my lungs are both damaged and not working to full capacity due to being on life support for an extended length of time causing the diaghram muscles to atrophy. All of my other muscles and systems have come back to life at full efficiency thanks to some heavy duty exercise and drugs... (now I have to get the weight back off) but the diaghram is the last to respond. Hence 'major' desats where minor desats should be. And it is easy enough to bleed 2-3L or up to 5L of O2 into the CPAP line and it is safe enough as you are mixing with forced airflow and venting, but the ideal is the system that was thunk of and which you, incredibly even to a tekky like me, whipped together in true ham radio fashion. I cannot remember when my last original idea was put to work... there were a couple that I missed the patents on but was certainly first to produce. One being the current sensing vehicle alarm believe it or not, circa 1970, because we could not afford all the darned pin switches and key switch that a standard vehicle alarm used at the time... so we whipped one together that sensed current changes when the lights came on and then added a motor kill relay from the junkbox. Another was a ham radio 'memory keyer' ... morse code memory generator, also circa 1970 and the price of memory at that time? A 256 BYTE memory chip cost $125 and all it sent was your callsign to keep transmissions legal (ID every 10 minutes). What you have whipped together reminds me very much of the excitement and challenge and satisfaction of finding a need and fulfilling it. Again, kudos. For that portion of the market that needs to maintain 95% SaO2 (or whatever the ideal number is) this is a godsend. It may well be the difference between a life of misery and lack of energy versus a life of productivity. Mine changed in the blink of an eye... I would like it back and I think the pulmonologist that I am seeing later this month is going to tell me that I have reached the point of being 'all that I can be' in terms of my lung capacity. I am hoping that they are not going to deteriorate further which will be my very first question... it would be good if my 70% capacity was static. I don't think it has improved one iota with all of the blowing exercises (pardon), walking, etc. I am going to ask what an 'ideal' SaO2 at rest is for a solid batch of REM sleep. I am going to ask for specifics of the perils of O2 infusion and CO2/CO masking (is it a dog chasing its tail?), etc. Will be in touch once I have that information in hand and hopefully a PhD pulmonologist onside... I have to figure any MD that would go ahead and get a PhD to boot has got to be curious and ambitious. In the meantime, I have taken the advice of the sleep doc and have cranked up the pressure a bit to see if it makes any difference in SaO2 levels... first night, as you know, was indeed improved but that could have been just a result of being better rested or an anomoly. I don't think this is going to be an overnight study, but it sure will become apparent in short order if keeping SaO2 up improves REM sleep. Don't think that will take very long to show results at all. I am also going to, BTW, look for an O2 analyzer so I can see exactly what percentage of O2 is reaching my face in the CPAP line.

Any thoughts on why all of my masks have two O2 nipples right on them?

[torontoCPAPguy]

My grandad used to say "The best sleep is the last sleep" - want to ensure it is still many years before I find out although I can tell you that when one is post H1N1 and with acute bacterial pneumonia, lungs filled to the brim with gunk and being suctioned, intubated and wired up like an F18 with tubes all the way up one arm and down the other.... strapped down to a high tech hospital bed that wiggles constantly.... it is a deep sleep. A few wierd dreams over three weeks but mostly just nothingness. Black. No tunnels. The one thing I forgot to ask is "was I snoring?".

[torontoCPAPguy]

It occurs to me that OSA/etc. is a very complex affliction - most readers of the forum do not realize that this is not just about cessation of snoring or getting a better night of sleep (although that is certainly part of the result we are aiming for) but rather this is more a matter of maximizing one's health overall.

To that end, SaO2 desaturation results in one thing two things in particular that strike me... the first being that SaO2 is generally inversely proportional to blood pressure - so one's blood pressure while asleep will tend to skyrocket in response to desaturations, causing all sorts of havoc including reduced liver performance and all of its inherent issues. The second being that reduction in SaO2 will most certainly result in the autonomic nervous system hollering at the body to wake up and breathe more deeply.... and the resultant lousy night of sleep due to lack of L4 and REM sleep due to the arousals to a higher state of consciousness.

The apnea events and hypopnea events can be generally be dealt with through XPAP and medication if indicated as I understand it. The aim of that game is to get AHI down as low as possible, preferably to 0.0. The name of the SaO2 game is to maintain an adequate SaO2 level during L4 and REM sleep, as I understand it generally in the 95% range ideally, in order to prevent awakenings/arousals from REM sleep and providing a good night of sleep. I'm sure that it is even more complex than this, obviously, but folks need to realize that it is not simply a matter of plugging in a leaf blower and stopping the snoring.

A complex beast, no? Still awaiting my oxygen concentrator and looking forward to meeting my pulmonologist with great anticipation, hoping she is not one of the 'nose in the air' types and will play ball with me. Else I have no hesitation in changing until I get someone who wants to get educated and to educate and play ball. Either way, I am going to infuse a small amount of O2 as soon as the concentrator arrives in order to get my SaO2 up to 95% and hopefully hold it there... next step is the feedback loop to provide just the amount of O2 needed for that task. THAT is really what I would like to do from the start and THAT is really what is being idicated from a clinical standpoint I believe. The sleep MD agrees and suggests I go back to school and become a physiologist.

[torontoCPAPguy]

Would anyone on here that is using infused oxygen please chime in and let us know exactly how much O2 you are infusing into your XPAP line and if you encountered any issues in doing so? Did you find it of benefit?

Thanks in advance.