Spirometry confusion help!

[Ninja457]

I've had a spirometry recently and the gp surgery have added the measurement "percent predicted fef" 3.03% on my records. Can anyone explain to me what the term means and what normal ranges are for it? I can't seem to find anything online. With the other measurements it states the predicted and then the actual % and these are all just over 80% which I believe is good, but not this one. It's talking about small airways disease online and under 65% being lowbut 3.03% is that my reading? If it is its incredibly low and what might that mean? I can post results if it helps. Many thanks ☺️

[soulsaver]

FEF = forced expiry flow - usually measured in litres per minute.

Is it against the 25/75 measure? Maybe best posting a scan up.

Best wishes

[Ninja457 in reply to soulsaver]

Hi Soulsaver thank you so much for your reply. Here's the extract on my NHS app. Do you think they mean litres? Is it possible to have such a low %? It mentions small airways disease online so a bit worried. Thanks for your help 👍

Fef 25-75 measure

[soulsaver in reply to Ninja457]

Well it looks like you've read it correctly. Hard to comment further without all the other measures and your background age weight lifestyle etc. You're a(n ex) smoker?

The main one is the Fev1/FVC ratio. If that's good as you imply, you won't be too bothered by SAD. Best to have a discussion with your nurse or GP who has access to your history.

Was this your first spiro? What symptoms made you have it?

[Ninja457 in reply to soulsaver]

Thanks yes I'm an ex smoker but quit over 10 years ago. Female age 44 I've put on a stone over the last 2 years mainly I believe due to not being able to run as much due to sob. I'm still a healthy weight though for my height etc. It's my first ever spirometry as the sob and chest tightness which prompted the test started during the pandemic and so I've never had a formal diagnosis of asthma or anything else. I've been on fostair 100/6 for that time and it has increased my peak flow but I still get sob mainly in mornings. I think the other measurements on my spirometry look normal apart from this one so I don't know whether that indicates asthma. They told me not to stop the fostair though before spirometry so i presume it might be normal then, but I don't see how it helps? They also added a note saying "serial peak flows consistent with asthma" I'm really at a loss as to whether it's asthma or something else. Sorry for such an essay and thanks for trying to help.

[Lysistrata Administrator Community Ambassador in reply to soulsaver]

I've seen varying research on whether FEF25-75 is a good/sensitive measure for small airways disease. I would say though Ninja457 that while 3.03% is very low, I think I have also read (and again potentially conflicting results here, and from memory) that it can be technique-dependent to some extent - so it may not be an accurate reflection, though may indicate there is some issue. You can also still have asthma where the small airways are more affected - it's not a separate disease necessarily, or automatically something awful.

The FEV1/FVC ratio isn't the whole story though - especially for whether there might be problems in the small airways. Not an expert, but I have severe asthma and my lungs often show pseudorestriction on spirometry ie reduced for both FEV1 and FVC, normal ratio, normal lung volumes mostly when measured, and mostly air trapping (and I'm not obese - saying that because I'm aware it can affect spirometry, as are you, but I note Ninja457 isn't obese either). Trying to work out my less usual patterns, I have done a bit of reading on this and as you say soulsaver, context is definitely important in spirometry interpretation (my job is focused on scientific/medical communication, so I do know how to read the papers - I even write them sometimes).

Obviously pseudorestriction is less common in asthma than other patterns, and can have other causes, and definitely not implying it's necessarily Ninja457's problem - but I've often found there's a lot of focus in the medical world on the ratio by itself, and in fact on spirometry itself without the context. Spirometry, and definitely when that's focused on just FEV1/FVC/ratio, doesn't seem to correlate especially well with symptoms either - both ways (ie symptomatic but spiro ok, not symptomatic but spiro not ok).

If they are trying to see if your spirometry is consistent with asthma though, Ninja457, then it's not telling them much to have you take Fostair before you do it!That's not to say anything terrible is going on that they have missed, but it's totally possible to have normal spirometry with even severe asthma, especially post-meds.

I also think they need to do reversibility testing if they really want to know ie you do spirometry, they give you some ventolin, wait 15 minutes and then do it again and see if the FEV1 has increased by at least 12-15% from baseline, based on guidelines. They won't have done that because your initial results are normal - but then again, we're back to the fact that you had your Fostair as instructed, so as you say I'm also not sure how this spirometry is helpful for deciding if you have asthma!

When you say serial peak flows consistent with asthma, was that a diary you kept at home? If you have a lot of variability in your peak flow, that can be consistent with asthma. Also if you've noticed that your peak flow goes up after you take your reliever (or Fostair, if you use that as a reliever). This post may be helpful - there's a lot of information on it and it may not be relevant to you, but it's a start: healthunlocked.com/asthmauk...

You may want to give the asthma nurses a ring and chat all this through, if you haven't already - they are lovely and very helpful and have more time and often more knowledgeable than GPs: 0300 222 5800 M-F 9-5 or WhatsApp - 07378 606728.

Apologies for this being a bit of an essay by the way!

[Ninja457 in reply to Lysistrata]

Lysistrata thank you so much for your response. That's really interesting that normal fev1/fvc ratio isn't absolutely everything. I think I just need to get an actual diagnosis if that's possible as this hads been going on for 2 years now and I still feel unsure of exactly what the problem is. Yes the peak flows were my diary at home. The asthma Nurse said they were a bit too varied I. E. Not a straight enough line on the graph and placed the entry on my record. I've got to increase my fostair to 2 puffs in evenings and report back in 2 weeks with peak flows again However if my spirometry was all normal (bar the fef 25-75) I'm not convinced about increasing fostair dose! I feel we have had 2 years of trialing various inhalers and we don't seem to really be able to remove all the symptoms. Maybe this is as good as it will get? I will question my asthma nurse when I speak to her in 2 weeks re the fef 25-75 as it will be interesting to see what she says and I will ask about the reversibility too. Thanks very much and take care 😊

[Lysistrata Administrator Community Ambassador in reply to Ninja457]

Glad it was helpful! I hope the nurse is helpful too - make sure you tell her you had Fostair before if she doesn't know.

I definitely wouldn't just use spirometry as the deciding factor though re dose increase - that's not how control is or should be decided. You should be aiming for reliever use no more than 3x a week with asthma. As I mentioned, spirometry isn't the best guide to asthma symptoms, though if your peak flow straightens out at a good level that's also an indication things are going the right way. Most people with asthma are able to achieve control of symptoms, but it can take some trial and error as you've found. This forum probably isn't representative as it's full of the people who have struggled to get control.

There are also other medications you can try if that doesn't do the trick, to add on to Fostair. Have you noticed any particular triggers/times of year you're worse?

[Ninja457 in reply to Lysistrata]

Ive found it really difficult to pinpoint any triggers, it doesn't seem totally predictable but I do get symptoms after eating some meals but not others and I have noticed home air fresheners or scented candles bring on chest tightness.

[Lysistrata Administrator Community Ambassador in reply to Ninja457]

Tight chest with air fresheners and scented candles is quite suggestive of asthma! It can be tricky with triggers sometimes as I find they aren't always immediate.I'd say the timing you mentioned is also relevant - asthma tends to be worse at night and early morning.

[soulsaver]

Messaged you with more questions. Happy for you to publicise the message if YOU want to.

Regards