Message Boards for the CF Trust

Replies: 6 Pages: 1

Garlicbread

Posts: 84
From: West Yorkshire
Registered: 11-Feb-2004

FVC
Posted: 01-Jun-2004 20:13

Reply

A bit ago i posted a message about increasing my FEV1. I wondered how my FVC seems so much higher than other people's even though they have a higher FEV1 than me. No body seemed to be able to answer my query so i thought i'd try again.

I know what the relationship is between the two and what they mean etc. I guess i'm comparing myself to others with CF, which i know is daft, but how come my FVC can be like 88% but my FEV1 is less than 60, whilst others have an FEV1 of say 67% and their FVC is like 60 odd.

I guess i just think that maybe i have a greater capacity to improve if my FVC is quite high. Could this be the case??

Help (softie)

XX

Darling

Posts: 731
From: Here
Registered: 06-Feb-2004

Re: FVC
Posted: 01-Jun-2004 20:25

Reply

A high FEV1% depends on being able to blow out hard and fast while the FVC is the lung capcity in total.

So someone who can blow out long and steady but not hard and fast may have a higher FVC than FEV1 % and vice versa.

I have quite a difference between FEV1 and FVC % but tonight I can't for the life of me remeber which way round it is.

With exercise you may develop more strength to blow a hard and fast FEV1 figure.

johanna

Posts: 18
From: Brighton
Registered: 09-Feb-2004

Re: FVC
Posted: 01-Jun-2004 23:07

Reply

I think that if you've got a lot of asthma problems your FEV1 will go down as well. I thought most people had a higher FVC than FEV1, but I might be wrong. I know that at least my FVC is higher.

Koko

Posts: 78
From: West Midlands
Registered: 13-Feb-2004

Re: FVC
Posted: 02-Jun-2004 13:07

Reply

By definition your FVC has to be higher than your FEV1 - or at least the same as. The equations for working out percentages are different though so your % can be quite different. I have a reasonably high FVC but my FEV1 can be a good 20% lower. Wheezing and lots of mucous can restrict the amount you blow out in the 1st second therefore your FEV1 can be lower than expected. There is a litre of air difference between my 2 statistics usually.

softie

Posts: 1,070
From: Croydon, Surrey
Registered: 07-Feb-2004

Re: FVC
Posted: 02-Jun-2004 14:27

Reply

The doctors generally go for how good your blows are compared to what is predicted for a person of your height. Also, I believe, for pwcf they also place more emphasis on the FEV1 than on the FVC. The FEV1 gives an indication of how inflamed and damaged and otherwise generally obstructed the airways are. I believe the FVC is more useful for diseases like emphysema where the damage can reduce the elasticity of the lungs (which reduces the amount of air that can be squeezed out of them) without obstructing the airways significantly.

It is easier to improve the FVC than it is to improve the FEV1. Exercise and breathing exercises can strengthen the diaphragm and the rib cage and "stretch" the lungs increasing the total capacity.

It is harder to improve the FEV1. It can be done, by doing all you can to eliminate any cause of inflammation. Exercise and physiotherapy remove mucus before it can be infected, rigorously taking prophylactic antibiotics reduces infection, rigorously cleaning nebulisers prevents reinfection, demanding antibiotics the moment you get an exacerbation reduces damage by infection, and making sure you are getting properly treated for asthma like symptoms helps with the physio and so on.

At the same time, you've got to make sure you still have time to live life after doing all this! It's a balance.

I hope this answers your questions. Take care,

Richard.

Garlicbread

Posts: 84
From: West Yorkshire
Registered: 11-Feb-2004

Re: FVC
Posted: 02-Jun-2004 18:10

Reply

Thanks guys,

I think i want an answer that i'm just not going to get to be honest. I'm half way through IV's at the moment and my FVC has gone up more, now at 93%. I just know that other Cfers have less FVC than me but a higher FEV1 and i just can't understand the logic despite the various explanations i get from others. Today i had a wopping 39% difference between the two. Yet some have just a couple of percent difference. I just thought the two could be interlinked somehow, but obviously not.

Koko

Posts: 78
From: West Midlands
Registered: 13-Feb-2004

Re: FVC
Posted: 02-Jun-2004 23:41

Reply

Do you want the formulae to work them out - I have them written down if you are a girl! Sorry boys. It takes into account age and height. I got them from my physio.