Confusing lung function results

[Claire-Rose]

So I had a recent lung function test which came back that my FEV1/FVC is 86% however my FEV is 1.15 when it should be 3.15(36%) and my FVC is 1.33 when it should be 3.71(35%). Does anyone know what this means and if it is normal or something to be concerned about as I feel fine and have done for months now.

[JonathanPittsCrick]

As a doctor but not a lung specialist, I can tell you that your results show that you are only using a small amount of lung to get your oxygen in (and your carbon dioxide out). It could be that you just have extremely small lungs, but this is unlikely if you are of normal size generally. Otherwise it means that either (1) you cannot fill your lungs more than part way or (2) you cannot breath out fully and a lot of air remains effectively trapped in your lungs, in so-called "dead space" – this would show up by another lung function test which can measure your dead space.

If (1), it could be caused by (a) your lungs not being stretchy enough (a "restrictive defect"); (b) your diaphragm not being able to move down because of pressure from your abdomen (if you are obese or have ascites); or (c.) there is a problem with the nerves or muscles that move your diaphragm or ribs.

The important thing to understand is that normal lungs have enough FVC for you t run a mile at full speed – and if you don't need or want to do that and are happy just walking about, you are only using about ¼ of your lung capacity. So your ⅓ lung capacity is plenty, provided it doesn't get much smaller.

You should ask your doctor what is the exact problem and whether a course of breathing physiotherapy would make the lung function better, or at least stop it getting worse. If the problem is restrictive, there are useful exercises e.g. one called "the triple breath" that may help you increase your FVC. If the prolem is obesity you will get better readings when standing up straight – and obviously the solution then is to lose weight.

[Claire-Rose in reply to JonathanPittsCrick]

Thankyou so much this is really helpful and makes a lot of sense as I do struggle to fill my lungs when I breathe in and out it feels like there is something on my chest stopping me but it doesn’t bother me.

[Bevvy]

Pleased you are feeling so well these days. I remember how much you struggled previously.

Suggest you speak to your consultant about test results. However I also believe that the very fact you feel fine is far more important than any figures. Figures on their own can be quite erroneous and not always give a true picture by themselves.

Again am pleased after struggling for so long to get correct treatment that you are currently feeling so well.

[Claire-Rose in reply to Bevvy]

Thankyou, honestly I do feel great haven’t been in hospital for 6 months and use to have weekly admissions I just worry because they stopped my last treatment of xolair because they didn’t believe it wasn’t working and I’m scared they might do the same

[Bevvy in reply to Claire-Rose]

I would have thought the simple fact you haven’t been admitted for 6 months will advise them it’s working!Have they given any indication of wanting to stop current treatment?

[Claire-Rose in reply to Bevvy]

No but they didn’t the last time either they said it was working then stopped it and said it wasn’t I think because of how they were the last time it worries me

[Bevvy in reply to Claire-Rose]

Yes but last time you were still having hospital admissions now you aren’t. Also isn’t it good they moved you on to a more effective medication?!I would be more concerned if your test results showed no issues because then it could indicate you have been miraculously cured!

But you are worried and we are not your doctors. So really I would have thought your best course of action would be to talk to your doctors.

[Claire-Rose in reply to Bevvy]

Thankyou you’re right I will talk to them. Have a nice new year