Started CPAP a few months ago..

[palerider]

So, with CPAP, more muscle force is used to exhale, and less muscle force is used to inhale = net difference of zero.

Unless you are using EPR or a bilevel setting, in which case your muscles get LAZIER.

I'll go with that.

You could also argue that the muscles got more exercise before CPAP because they had to struggle to breathe (apneas).

we're not talking about the diaphragm, which might possibly be involved in your ... theory

[lowsats]

Jay,

Like we have said, while youre using supplemental O2, that increase in oxygen that is floating around in your blood will only be there for about 10 or so minutes until the levels drop back down to normal (what your lungs are capable of maintaining unassisted). But CPAP is incredibly efficient at increasing oxygen saturations. Heres an example I would always teach to my students:

Avoiding all technical jargon and medical/anatomy terms as much as possible....

Normally:
Inside your lungs there is a membrane that makes contact with blood and air that allows the diffusion of gasses, mainly the exchange of oxygen and carbon dioxide, hence respiration occurs (there is a huge difference between respiration and ventilation). The oxygen goes into your blood and the carbon dioxide gets offloaded from the blood and expelled via your exhaled air.

With CPAP:
The air pressure within all of your airways (sometimes called "dead space" if its not involved in the exchange of gasses) becomes increased, the pressure helps to pop open little air sacs in your lungs and allow more of them to participate in the exchange of gasses. The air also gets pressed harder against that membrane that we mentioned earlier which allows more oxygen into the blood stream and thus makes the exchange of gasses more efficient when compared to unassisted atmospheric pressure.

Think of it like this. If I had a fist full of m&m's and I wanted to give you some. Which way of giving them to you would be more effective? Slapping your hand and hoping maybe you got a few candies? Or pressing my hand firmly against yours and giving you all the candy I could in that second?

So the long answer is without knowing your specific situation and underlying pathology or pre-existing conditions, there is no DEFINITIVE answer to your question. I have years of emergency medical experience and have put hundreds of patients struggling to breathe on CPAP and seen instantaneous marked improvements in their condition. But this is much different than our cases with treatment of OSA.

[ChicagoGranny]

Because last year I was told when I went in for a hernia surgery that my low SpO2 during the day was a sign of possible OSA.

Some smart surgeons and anesthesiologists are watching for their patients to stop breathing during surgery. If they see it, they later alert the patient that he might have OSA. That's probably what happened in your case.

[thejsays]

Jay,

Like we have said, while youre using supplemental O2, that increase in oxygen that is floating around in your blood will only be there for about 10 or so minutes until the levels drop back down to normal (what your lungs are capable of maintaining unassisted). But CPAP is incredibly efficient at increasing oxygen saturations. Heres an example I would always teach to my students:

Avoiding all technical jargon and medical/anatomy terms as much as possible....

Normally:
Inside your lungs there is a membrane that makes contact with blood and air that allows the diffusion of gasses, mainly the exchange of oxygen and carbon dioxide, hence respiration occurs (there is a huge difference between respiration and ventilation). The oxygen goes into your blood and the carbon dioxide gets offloaded from the blood and expelled via your exhaled air.

With CPAP:
The air pressure within all of your airways (sometimes called "dead space" if its not involved in the exchange of gasses) becomes increased, the pressure helps to pop open little air sacs in your lungs and allow more of them to participate in the exchange of gasses. The air also gets pressed harder against that membrane that we mentioned earlier which allows more oxygen into the blood stream and thus makes the exchange of gasses more efficient when compared to unassisted atmospheric pressure.

Think of it like this. If I had a fist full of m&m's and I wanted to give you some. Which way of giving them to you would be more effective? Slapping your hand and hoping maybe you got a few candies? Or pressing my hand firmly against yours and giving you all the candy I could in that second?

So the long answer is without knowing your specific situation and underlying pathology or pre-existing conditions, there is no DEFINITIVE answer to your question. I have years of emergency medical experience and have put hundreds of patients struggling to breathe on CPAP and seen instantaneous marked improvements in their condition. But this is much different than our cases with treatment of OSA.

Thank you for taking the time to go through all that. I appreciate it.

[thejsays]

Because last year I was told when I went in for a hernia surgery that my low SpO2 during the day was a sign of possible OSA.

Some smart surgeons and anesthesiologists are watching for their patients to stop breathing during surgery. If they see it, they later alert the patient that he might have OSA. That's probably what happened in your case.

Actually what happen was when I went in the morning of my planned outpatient surgery for prep, the nurse prepping me noted that my Sp02 was on the low side and just mentioned that sometimes that can be associated with or a sign of sleep apnea. They monitored me for a quite a while to see if it would come up before my surgery but it didn't (unless I took multiple purposely deep breaths but as soon as I stopped purposely breathing heavily my Sp02 would drop again). They still eventually went ahead and did my hernia surgery but they ended up keeping me on oxygen & kept me overnight to monitor me instead of as an outpatient.

Months later when I went for my sleep study they told me my Sp02 was dipping in some cases to around 70 while I was attempting to sleep. After I started the cpap I am sure that helped prevent the worst case stuff that was observed during my study overnight... But then when a couple months later I did an overnight oximetry test on my cpap, my doctor recommended I start on oxygen bled into my cpap as well. I didn't see/hear what my Sp02 numbers were form the overnight oximetry monitoring but apparently they were not sufficiently improved to avoid my doc prescribing oxygen therapy to be used with my cpap.

I suppose I may just assumed the cpap & oxygen treatment would help my daytime/awake Sp02 levels as well. And then when I spoke to my doctor about hoping to see improvement on that with the treatment, she never told me that wouldn't be the case so I took that to be a sort of confirmation of my assumption. Perhaps it was a communication error facilitated by me naturally seeking confirmation for the belief I had already formed.

Thanks for the help though.

[ChicagoGranny]

But then when a couple months later I did an overnight oximetry test on my cpap, my doctor recommended I start on oxygen bled into my cpap as well.

What was your AHI the night you did the oximetry test? You do know that when using CPAP you could still be having apneas if the pressure settings are not optimized, your mask is leaking, you are mouthbreathing with a nasal interface or any combination of these?

[thejsays]

But then when a couple months later I did an overnight oximetry test on my cpap, my doctor recommended I start on oxygen bled into my cpap as well.

What was your AHI the night you did the oximetry test? You do know that when using CPAP you could still be having apneas if the pressure settings are not optimized, your mask is leaking, you are mouthbreathing with a nasal interface or any combination of these?

I don't know.
I know I typically do not have any issues with mouth breathing or mask leaks according to the the machine reporting and on my cpap I average <1 apnea an hour.