Ally, you had high pyruvate and lactic acid? Are you sure you don't have a mitochondrial myopathy/cytopathy?
http://www.mitochondrial.net/showabs...tase+increased
http://emedicine.medscape.com/article/768159-overview
I'm not Alice but I can answer a couple questions.
With MG, there is a progression (often but not always) of what happens. And I'm paraphrasing from a book on MG (and my own experience). O2 sats drop lower late in the game with MG. They may drop a bit at first. Then there is hyperventilation on arterial blood gases. By this time, someone with MG is already in trouble. The step after that is CO2 retention, which is BAD. You need help immediately at that point.
You can go straight from "ok" to CO2 retention too. There's no predictable way that your respiration will go south. And, yes, too much CO2/not enough oxygen seriously affects both the heart and brain.
Ask your pulmy about the BiPap, or whomever ordered it.
There just isn't an equivalent of an oximeter for CO2. You can read this:
http://www.fpnotebook.com/Lung/Lab/OxygnStrtn.htm
You really have to go by how you are feeling and an oximeter if you have one. When in doubt, go in!!!
Seriously, has anyone done a muscle biopsy for you?
Annie