Confused about FVC!

[stephie]

I am wondering if anyone can help me understand FVC better. Shortly after diagnosis, my husband's FVC measured 120% (he was a strong 39 year old). His FVC declined about 5 or 6% every three months and is now( 3 years later) at 18%. The pulmonologist said he will probably not continue measuring it at his ALS clinic visits because it is too low for an accurate measurement.

The thing that puzzles me is that my husband only uses bi-pap at night. He does not have breathing problems when he is sitting up in his wheelchair. A couple of months ago when his CO2 was measured, it was in the low-normal range. My question is, how can his FVC be so low when he seems to be breathing fairly well? Should I expect a rapid decline in breathing capacity now that his FVC is so low, or will it continue to gradually get worse? I know each person is different, but 18% FVC is very low!

 

[Miss]

Stephie,

I am a bit confused, too. My husband's FVC was 125% in January, 2010; 81% in May, 2010 and 55% in Sept.,2010. He is only on bi-pap at night, and his CO2 levels are fine. I do notice that he takes very deep breaths after any exertion, though.

 

[abbas child]

Is there an inability to seal the mouth over the tube while doing the test? It could possibly show a low score due to mouth seal being bad.

 

[brooksea]

I agree with Ann! Bulbar issues may be preventing accurate test results.

 

[Miss]

In our case, they watched for that and did about 10 other types of tests to check things out. Same results.

 

[abbas child]

Forced Vital capacity (FVC) can test low on someone who still seems to be doing pretty well, and can test rather high on someone who then dies in their sleep, going strictly by reports at PLM. Other tests are said to be better for ALS. I have not had the MIP or MEP, but Rose had them (at least she had at least one of them done at Hopkins). They are much more centered on muscle strength.

Here's what I found just now: Respiratory muscle strength can be assessed by measuring the maximal inspiratory pressure (MIP, PImax, or negative inspiratory force [NIF]) and the maximal expiratory pressure (MEP or PEmax). The MIP reflects the strength of the diaphragm and other inspiratory muscles, while the MEP reflects the strength of the abdominal muscles and other expiratory muscles.

The high FVC is often simply due to lungs working hard as the body tries harder to move. My own (first) score was 135% before I began using a power chair. I heaved for breath during that time, and later began breathing more normally... A year later I had a score of 99%.

There are still other methods considered good for PALS. FVC is the accepted "guideline test" here, but doesn't sound like the most effective way to test us.

 

[rkyoung]

I'm confused also even though I know the correct assistance is a BiPAP, I am arguing with the Hospice nurse over the oxygen machine. My sister can't draw in a breath. How is an oxygen machine going to help? BiPAP assists air into the lungs keeping them inflated. The misinformation by this nurse is interfering with my efforts to get my sister to use the BiPAP. My sister doesn't like the mask over her face all the time. Any excuse to resist using it is good enough for her. My mother is similarly resistant to the fact that the BiPAP is the correct solution. I'm tired of searching for the solution, then fighting to implement the solution. I just don't want to push it anymore. When she can't breathe anymore and the tracheostomy is the solution, what do I say? I told you so? I just sick of it!

 

[Pat Paine]

Dear RK,
Can you have your sisters' neuro or better yet her ALS doc speak to Hospice as well the family to educate them and relieve you of all of the burden you are carrying? Your sister is lucky to have you in her life.
I am praying you get some help soon. You are not alone here.
Pat