Low CO2

[swalker]

I had my most recent Arterial Blood Gas (ABG) and spirometry yesterday. The results are a bit confusing to me and I would appreciate any insights you have to help me understand the implications of the results.

The spirometry showed an FVC of 21%. This is a slight decline from 6 months ago when it ws 23%.

Over the past several years, the ABG has shown a CO2 level in the normal range, but steading increasing (in the mid 30s).

Yesterday, the ABG showed a CO2 level of 24.1 resulting in a pH level of 7.538. O2 saturation was 96%.

FMetHb was slightly elevated at 1.1%.

I discussed these results extensively with my pulmonologist. He was not concerned about the ABG results and said the high CO2 level could have been from hyperventilation.

That is consistent with what I have read on google, but...
1. I did not feel at all like I was hyperventilating. I don't have a problem with needles and have had many AGB sticks. Nothing to get excited about for me.
2. I don't see how I could hyperventilate with such a low FVC.

What do you think?

Thanks for your help!

Steve

 

[lgelb]

So before your CO2 was going up, now it's down, and your pH is high. This could relate to respiratory alkalosis.

In respiratory alkalosis, your alveoli take in less air than they did, which would not be surprising in MND. I would want to have your bicarb and electrolytes checked next since low [for you] CO2 and high pH can also be seen in metabolic acidosis and that would suggest other issues to rule out.

Best,
Laurie

 

[swalker]

Thanks Laurie. I will follow up on this and see what it reveals. I am guessing a respiratory cause.

Steve