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+--- Thread: Increase in AHI with Oxygen, but feel better (/Thread-Increase-in-AHI-with-Oxygen-but-feel-better)
Increase in AHI with Oxygen, but feel better - u2canbuild - 03-05-2015
I usually use an oxyen concentrator in addition to my CPAP but notice that my AHI is about 30% higher when adding oxygen, However I almost always feel better in the morning with oxygen and my SPO2 is steadier and higher.
I spent 8 days in florida with my CPAP but no oxygen added, I had some ok days and some very tired and confused days........
Upon return to home yesterday and using my usual 1.5 to 2.0 L 02 ............I had an AHI 3 times my usual............ but woke feeling clear, no headache and had a great day.
Anyone else experience this?
Any ideas on what may be happening and or suggestions?
RE: Increase in AHI with Oxygen, but feel better - eseedhouse - 03-05-2015
Interesting. I noticed no change in my AHI when the oxygen was added into the mix. I definitely started feeling better, though.
RE: Increase in AHI with Oxygen, but feel better - AshSF - 03-06-2015
I am guessing most of the increase in AHI is central apnea events. It probably happens because you are taking more enriched air thus your end tidal CO2 is being lowered. If your end tidal Co2 is lower than usual, the brain may make your skip a breath or two to increase your co2 level.
It can be explained due to 2 things:
1) Higher pressure support. In your machine, the EPR feature is a pressure support of 1, 2 or 3 cm h20. More PS means more CO2 washout leading to central events.
2) More oxygen enrichment leading to more O2 and less CO2.
You should talk to your sleep doc/pulmonologist to see if your O2 enrichment level needs to be titrated. Although if you are feeling great and AHI is less than 5, it may be just nitpicking.
RE: Increase in AHI with Oxygen, but feel better - PsychoMike - 03-06-2015
Probably wouldn't hurt to look at the type and duration of events. I'm like AshSF...I'd guess the centrals went up. I'd also think that the length of the events would be important.
If the events are relatively short (i.e. 10-12 s) there might be some fine tuning to do...if they are larger, it may mean a bit more work. If you need the supplemental 02 at night, then you may also need to look at a different style of machine (like an ASV) to deal with the centrals.
RE: Increase in AHI with Oxygen, but feel better - vsheline - 03-07-2015
(03-05-2015, 09:21 PM)u2canbuild Wrote: Any ideas on what may be happening and or suggestions?
(03-06-2015, 12:05 AM)AshSF Wrote: It can be explained due to 2 things:
1) Higher pressure support. In your machine, the EPR feature is a pressure support of 1, 2 or 3 cm h20. More PS means more CO2 washout leading to central events.
2) More oxygen enrichment leading to more O2 and less CO2.
Hi u2canbuild,
Most patients find that their OSA is strongly positional. If your sleeping position away from home was mostly on your side and if at home you tend to spend more time sleeping on your back, this could explain the higher AHI at home, but only if the increase is from obstructive events rather than central apneas.
Hi AshSF,
Actually, studies have shown that adding O2 tends to reduce the frequency of central apneas, although not by much.
This kinda makes sense if you think about it from the following perspective.
When the air we are breathing is enriched with more O2, this increases the amount of O2 in our blood, so we are able to use more O2, which leads to more CO2 (used O2) in our blood, not less.
So I think it is a misunderstanding that supplementing with O2 will tend to lower our CO2.
Take care,
--- Vaughn
RE: Increase in AHI with Oxygen, but feel better - AshSF - 03-07-2015
(03-07-2015, 03:44 AM)vsheline Wrote:(03-05-2015, 09:21 PM)u2canbuild Wrote: Any ideas on what may be happening and or suggestions?
(03-06-2015, 12:05 AM)AshSF Wrote: It can be explained due to 2 things:
1) Higher pressure support. In your machine, the EPR feature is a pressure support of 1, 2 or 3 cm h20. More PS means more CO2 washout leading to central events.
2) More oxygen enrichment leading to more O2 and less CO2.
Hi u2canbuild,
Most patients find that their OSA is strongly positional. If your sleeping position away from home was mostly on your side and if at home you tend to spend more time sleeping on your back, this could explain the higher AHI at home, but only if the increase is from obstructive events rather than central apneas.
Hi AshSF,
Actually, studies have shown that adding O2 tends to reduce the frequency of central apneas, although not by much.
This kinda makes sense if you think about it from the following point of view.
When the air we are breathing is enriched with more O2, this increases the amount of O2 in our blood, so we are able to use more O2, which leads to more CO2 (used O2) in our blood, not less.
So I think it is a misunderstanding that supplementing with O2 will tend to lower our CO2.
Take care,
--- Vaughn
Hi Vaughn: Thanks for the clarification.
RE: Increase in AHI with Oxygen, but feel better - PsychoMike - 03-10-2015
Vaughn, I can't fault your logic for the average user. But I still wonder about the supplemental O2 that u2canbuild is on. If it is at all related to emphysema or COPD, it could be the issue.
For most folks, the level of CO2 drives their breathing and that production is fairly constant. For someone with a hypoxic drive, it is the level of O2 that drives the breathing...dropping O2 level vs. increasing CO2 levels like in normal folks. In that case, like in COPD, when you add supplemental oxygen, it decreases the breathing rate as the hypoxic drive isn't getting the same trigger...that would lead to more centrals.
I'm not doc, but I thought I'd float that one out there
