O2 Supplement with CompSA

[bombadil]

I was diagnosed in May with complex sleep apnea and given a ResMed VPAP ASV (EEP 8, PImax 15, PImin 3) and an oxygen generator with a recommended bleed of 2 L/min. AlphaSleep reported that during the sleep study, the oxygen was required to get the AHI under 1.0.

I guess I'm one of the lucky few. I've been able to use the machine all night from the third night on, and I felt incredibly better, even after the first night. There were some problems with mask leaks until I learned how to adjust the mask.

It's been going so well that I started wondering whether the oxygen was necessary. I got a Clinical Manual for the VPAP and found out how to access the results in the Clinical Menu. (Apria, my DME, told me nothing about this, and I found out about it by reading on this site.) So I checked the AHI, and the averages were

3 month: 1.0
1 Month: 0.4
1 Week: 0.3
1 Day: 0.4

From what I see here and elsewhere, these are very good numbers. So I tried it last night without the oxygen and got 0.3 for the AHI.

So I'm thinking of discontinuing the oxygen. Does anyone know any reason not to do this? Does the oxygen serve any other purpose than helping to lower the AHI?

For reference, here are all the parameters:

Leak: 7L/min
AHI: 0.3
AI: 0
Avg. Press.: 9.8
VT: 287-595
Resp. Rate: 13-17
MV: 4-8

I don't know what some of these mean. I'm puzzled by the leak rate, since I was consistently getting 2L/min with the oxygen on at that rate. I did notice that I had absent-mindedly connected the oxygen line even though the oxygen generator wasn't running, so that may be the cause. I'll try it tonight with the port capped.

Anyway, advice on whether to discontinue oxygen would be welcome.

Thanks, everyone, for a great site!

[jabman]

I beleave that the Oxygen has to do with your O2 sats when you were Dxed with OSA. your could of been low, your sleepstudy results will show what it was. Myne was droping down into the 70% range, I think the 96% range is where it should be at. I don't use an oxygen suppliment my self. Alot of people here use a oxemeater to see what there range is at night. I am sure someone with more (and better) information will be able to tell you more.

[bombadil]

Thanks for the suggestions, jabman. I don't have a copy of the results of my sleep study. Maybe I should get one.

I guess my O2 saturation could be low, even with a very low AHI? That hadn't occurred to me. I've thought about getting an oximeter, but the ones I've seen all have Windows-only software, and we're an all-Mac household.

[Mary Z]

As already stated the O2 is generally prescribed if your O2 sats are low during the study. If you did not discuss this with your doctor perhaps you could on a check up. I would not stop the O2 based on my AHI without medical approval. Good luck, keep us posted.

[bombadil]

Thanks for the replies. Does anyone know what could be causing the oxygen stats to be low, given that the apnea appears to be well controlled?

[JohnBFisher]

The other reason that oxygen might have been prescribed is to try to break the overshoot / undershoot cycle.

Central sleep apnea (even from complex sleep apnea) occurs when for some reason (in your case too much pressure), the body fails to breathe. This increases the CO2 levels in your body. This is the undershoot side of the cycle.

Eventually, your body kicks in and starts breathing again. But it tends to overdo it a bit. You tend to hyperventilate and blow off too much CO2. This depresses the respiratory drive. It's actually the level of CO2 in the blood that drives respiration (during sleep). This is the overshoot side of the cycle.

And of course, by overshooting and expelling too much CO2, the body is set up once again to an apnea. And the cycle repeats, over and over and over ...

You can help break this cycle by either increasing respiration (by increasing pressure and increasing the air moving into the lungs). That's the "adaptive servo-ventilation" part of the unit. It acts as a respirator to try to help you maintain respiration.

Of course, it sounds as if increasing pressure is not such a great option for you - due to the complex sleep apnea. So, to help improve the respiration the sleep tech probably tested without and then with oxygen. It sounds as if you need both the ASV unit *AND* the supplemental oxygen.

You can certainly try sleeping without it. But remember after a while you might have more apneas (and a greater AHI score).

Remember, this is just speculation based on my reading and discussion of my own condition (central sleep apnea).

Hope that helps.

[bombadil]

Thanks, John, for your helpful ideas and comments. In fact, after leaving the oxygen off for just one night, I began to have a headache and some depression, just like I did before diagnosis. So the oxygen is definitely doing some good, even though the AHI was still very low. My guess is that the VPAP ASV "thinks" it's dealing with the central events, and so doesn't count them in computing the AHI, but its effect on them doesn't completely take care of them without the oxygen to help break the overshoot/undershoot cycle. So it's a deficiency of the reporting mechanism in the machine, or of the lack of oximetry data to get the fuller picture. As you say, the sleep tech would have seen the oxygen levels and judged correctly.

I'll be continuing the oxygen.

Again, thanks, everyone.

[JohnBFisher]

... So it's a deficiency of the reporting mechanism in the machine, or of the lack of oximetry data to get the fuller picture. ...

I think the latter is the more likely. You don't have the oximetry data to determine if by supporting your breathing the machine has improved your situation. It sounds as if you need the extra O2 to help you get over the hump. The ASV sustains your breathing, but for some reason the O2 is needed to keep your O2 levels in the safe zone.

[Roger2]

Does anyone know what could be causing the oxygen stats to be low . . .

It might just be that you have a totally different need for the added O2 than sleep apnea. I have been on external O2 for over ten years and it has nothing whatever to do with my sleep apnea. I managed to permanently damage over half of my lungs surface from 26 years of smoking cigarettes, the last ten years of which were very heavy; I was a real chain smoker. Now at the altitude I live at in Colorado my lungs simply can not take enough O2 from the air to keep me going. I have only been diagnosed with OSA since May this year but the hypoxia predated that by many years.

You might want to see a pulmonologist as this kind of hypoxia is their bailiwick, not the sleep doctors.

Roger

[bombadil]

My PCP did a COPD test when I first reported shortness of breath after awaking. The COPD test was negative, and the morning shortness of breath went away when the sleep apnea was treated. I do live in Denver, so altitude may be a factor, but I don't have shortness of breath climbing stairs, and I regularly do cardio at the gym with no problems.