It was debated back and forth by multiple doctors whether my VQ scan in Sept 2014 (when my breathing really started to decline and prior to this was still walking and driving) whether I had a ventilation/perfusion or V/Q mismatch
maybe the following will be all trivial... but as you do not mention this simple investigation for perfusion / ventillation mismatch, I just write it down for the unlikely case that it is not done yet. A further caveat is that all this helps only in case that the perfusion / ventillation mismatch means too much perfusion or too little ventillation. (otherwise round it wont help).
Have you had standing-laying SpO2 done?
You can do it at home with a cheap device. This saves you from
- allergy causing dyes
- doctors who do not understand your disease
What is SpO2 and why is it important?
just as a simple introduction for people reading this and not yet familiar with the topic:
SpO2 is the measure of how many % of oxygen is carried by the RBC compared to full saturation (100%).
if breathing is not adequate to oxygenate all the blood flowing through your lungs, or blood is flowing too fast through the lungs, then you will have a low SpO2.
<95% is hypoxemia:
http://www.ncbi.nlm.nih.gov/pubmed/12135174
<89% is bad hypoxemia:
http://www.ncbi.nlm.nih.gov/pubmed/17709927
this is where organ damage starts on the very long run.
I just got interested in this topic because my polyneuropathy worsens on this. Any other organ will suffer damage on the long run, too. see the discussion here. unfortunately, they do not cite research:
https://healthunlocked.com/blf/post...n-level-is-damaging-other-organs-of-the-body-.
I did not find autoritative numbers on this, various sources cite various numbers such as <92% or <90% or <89%. But the SpO2 devices are anywise not that accurate:
http://www.ncbi.nlm.nih.gov/pubmed/25978517
Then there is a second threshold, where organ damage starts within hours. I think that is around 85% or 80%, and then there is a third limit where one has damage immediately.
Using SpO2 for diagnosis
SpO2 is interesting and highly diagnostic, because in some diseases it gets better upon standing, in others worse. For example in me, SpO2 gets better upon standing (95%), while laying worse (89%). Also, in me it sometimes fluctuates strongly between these two values. These two facts are diagnostic for the situation where a vasodilator coming from another organ enters the lungs. It causes there the blood vessels to dilate -> flow resistance decreases -> blood flows too fast through the lungs, compared to the oxygenation capacity (which is lightly reduced in me but would not cause any probs in itself).
Which vasodilator is the culprit?
Excessive vasodilators as contributors to POTS, OH and low SpO2
Here is my list how to test for various vasodilators.
http://forums.phoenixrising.me/index.php?threads/pots-relief-could-it-be.42775/page-5#post-752424
This is relevant for POTS and OH in general, because vasodilators can make these diseases much worse, independently of any good or bad SpO2.
But vasodilators are also a culprit for mismatch of ventilation and perfusion. For the latter, the main suspect is usually nitric oxide from the gut, but the pathomechanism does not at all rely on NO, but simply on vasodilatation in the lung.
NO is usually elevated in cirrhosis and other liver diseases (hepatopulmonary syndrome), but I do not have that. So I do not know from which organ my vasodilator comes. Possibly the gut, because I have a low SMA resistance index, but then it is unclear why, as I have no liver issues. See here for more on intestinal blood flow:
http://forums.phoenixrising.me/inde...blood-flow-standing-laying.45909/#post-746572
How to test for SpO2
SpO2 is very simple to measure. For a first measurement, any pulmonologist can give an SpO2 meter for a day. Then, if positive and you want to test regularly: Buy an SpO2 meter. Spend a tiny bit more money so you get one with nightly recording and export to PC. I bought this one:
https://www.amazon.co.uk/Wrist-pulse-oximeter-PULOX-PO-400/dp/B003ITM3WI
It is cheap and stupid chinese crap and I would have loved to invest a 100 bucks more. but it is the only one I found that has:
- nightly recording (this is so important because at night spo2 can drop badly)
- export to PC (so you can print out and show doctors)
- is in the form of a wrist watch (this is the only form that is practical for nightly recording. I would not buy anything that hangs on your phone, because what happens if you turn around in bed. equally not anything that only clings to your finger because it will get out during the night)
The drawbacks are:
- does not cooperate with mac, so mac users need parallels
- is user unfriendly
- the software connecting it with the pc is extremely difficult to use
- the device easily switches on when in a bag
- can store only a single recording, so you must export it every single time
in sum: stupid cheap chinese crap.
but all better devices I found are immediately some 1000 bucks. I failed to find a good device for some 200-500 € or $