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Peak Flow doesn't always drop despite being symptomatic.

CANINE12 profile image
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I was reading Lysteria's post about taking your details to take to A&E etc.

She mentioned that her peak flow doesn't drop during an attack. I have an appointment coming up next month with the Severe Asthma Team where I feel I should mention this again. I've mentioned it in the past and my consultant said peak flow always drops during an asthma attack.

I have the usual tight chest, shortness of breath as well as feeling like I'm drowning and I'm bringing up clear phlegm so I know it's not a chest infection.

I would be interested to hear anyone who's consultant has acknowledged that you can have an asthma attack and your peak flow remains normal.

So do I challenge them about it or not?

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CANINE12
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Lysistrata profile image
LysistrataAdministratorCommunity Ambassador

I wouldn't ever bother with mine, but then he has very narrow views about what counts as an asthma attack (if there aren't eosinophils/raised FENO, he's not interested). He's also decided that my peak flow technique is wrong because I struggled to use a home electronic meter previously, without any guidance. I've gone back to manual and used that for ages, and his team have checked my technique more than once and said it's fine. But apparently it doesn't count unless he sees it so he just keeps writing that it's unreliable. 🙄

Does your peak flow drop much at all, or just not below 50%? Is your personal best similar to your predicted, and if it's higher, is that acknowledged? I feel like I have to tell them my personal best every.single.time I go in and they never seem to record it officially. i wouldn't mind if they checked it's still the same, but they just assume my predicted when I've specifically told them and got my PB in clinic.

Just to clarify, as I only mentioned it in passing in my other post: my peak flow does kind of drop, but it tends not to drop to the levels 'required'. It's most likely to sit in low yellow zone, but I've had dodgy ABGs before and a severe attack more than once with a peak flow of 400 (that's about 63% of my best). One time it did actually go below 50% best but that really wasn't one of my worst attacks!

I find the pattern is more helpful personally. I go through a period where I'm getting worse but I can still get my peak flow up to high green with treatment, but it doesn't last. Then I can't get it as high and it doesn't last as long. Then the response just keeps dropping until I can't shift it anymore. (By this point I definitely need to be in if not before). I've read in one of the papers I had to look at for work that this is actually a classic pattern (I work in healthcare communications, so I know how to read scientific papers and even write them at times),

Coming out, it goes the other way - I get higher and higher for longer and longer after nebs and then can maintain without them, or just with an inhaler.

Peak flow isn't supposed to be used as the only way to decide attack severity, but it is too often. I got a random pointless letter once after an admission just telling me my attack was 'moderate' based entirely on peak flow supposedly from the 2016 BTS guidelines (spoiler, it was not moderate). I mean they used my personal best at least but my reaction was a) why are you using the guidelines from 3 versions ago, the latest ones are free online, I've used them for work and b) have you actually read them properly? Though to be fair, they make it really hard to get important information from.

I'm not sure how open and receptive your consultant is - if the person you're seeing seems reasonably open you could try explaining in more detail exactly what you mean and what you've noticed about how your peak flow behaves during an attack? He *might* be more open to detail beyond 'it doesn't drop' eg 'it doesn't drop as much as I'd expect/below 50%' or whatever you notice.

I had a previous consultant tell me not to seek any medical care if my peak flow was above 50% predicted. Needless to say this is a terrible idea, if I'd followed it I might not be here now given how my asthma presents, and it's not what is advised by Asthma + Lung UK. For anyone else reading this, please don't wait for your peak flow to drop if you have other signs you need to be getting medical care asap.

CANINE12 profile image
CANINE12 in reply to Lysistrata

That sounds very frustrating to have a consultant who has tunnel vision. He doesn't appear to trust his team in their capabilities for assessing technique either.

My PF (peak flow)does sometimes drop depending on the trigger or if the attack is extremely bad. I have used a nebule in my portable nebuliser (Dr's allowed as I can deteriorate very quickly) and my PF was ok but my sats had dropped to 90. Sometimes my O2 is ok but my carbon dioxide levels aren't.

My personal best PF is higher than the predicted which fortunately they have acknowledged.

It's very interesting what you wrote about patterns with PF.

How can they decide severity of an attack based only on PF. That's a basic error, I wish all Dr's and nurses were trained properly in dealing with asthma attacks and not make assumptions about patients.

I had a very helpful chat to one of the nurses on the helpline. I'm going to make a daily note of the severity of each symptom and take a summarised version to my appointment. As well as making sure I take the results of the allergy tests I had at a different hospital (taken for a different problem).

I completely agree, never rely on peak flow alone as the way to determine how bad your asthma is. If symptoms are bad or if in doubt always seek medical help as soon as possible.

runcyclexcski profile image
runcyclexcski

>>>I have the usual tight chest, shortness of breath as well as feeling like I'm drowning and I'm bringing up clear phlegm so I know it's not a chest infection.

I am the same. My PF only drops if I am really sick. My asthma was primarily diagnosed by a rapid drop of air flow rate in a spiromtery test (25-75%) which was 40% of the predicted, whereas my PF was 140% predicted. Also, they diagnosed it by eosinophilia. When A&E people bring out a peak flow meter to "diagnose" me, I get so upset that I get panic attacks :). I had my nurse fill out a form explaining that my PF is 140% predicted.

My theory is (which, I believe, I picked on reading Pubmed and Google scholar) is that my inflammation is primarily in the small airways which are quite difficult to pick with PF and other old school methods that work for 90% of people. There are other tests for small airway inflammation -- NO etc.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to runcyclexcski

The problem with using NO (or FENO as the test tends to be called) is that it's looking for one type of inflammation, which not everyone has, and it won't pick up if the airways are narrowed but there isn't eosinophilic inflammation. Of course, peak flow isn't directly measuring inflammation in the large airways either - it's not telling you why they might be narrowed. Currently I don't think there's anything that both measures directly how the airways are behaving at that moment and what is causing this ie is there inflammation, what kind? I know people who do have eosinophilic inflammation and their FENO can be raised, but not always in line with how the airways are behaving: there's a lag so their increase in FENO comes after the acute period.

I think there is ongoing research into looking for effective ways to measure small (and large) airway obstruction, and inflammation. I participated in some early user testing last year for a device which aimed to measure about 14 different parameters including things like breath temperature, but I never heard anything more - they were planning to go into clinical trials but wanted some feedback from an asthmatic on how the device and app actually were to use. I hope that does work out as I would like to see less reliance on single measures.

I would also really like to see less reliance on peak flow, better ways to measure airways of all sizes (and understanding by healthcare professionals of the limitations of current methods), and better understanding of non-eosinophilic causes of bronchospasm/non-eosinophilic inflammation.

CANINE12 profile image
CANINE12 in reply to Lysistrata

I completely agree with you regarding your last paragraph. I guess I could be described as a unicorn asthmatic.

I have become so used to symptoms that they have become normal for me. So I had told the consultant that my asthma is fine in the winter but clearly it isn't. I wasn't taking into account the drowning feeling as an asthma symptom.

I only became aware that it could be an issue because I had allergy tests done at a different hospital because my GP was checking certain foods I was eating weren't causing digestive symptoms because of an allergy. I tested positive for Cladosporium Herbarum a type of mould found in leaf litter. So it's no wonder I'm symptomatic at the moment.

It's a pity the researchers didn't get back to you Lysteria.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to CANINE12

Ha check out my avatar here, re unicorns! Lack of eosinophilia seems to go hand-in-hand with that label. And I understand 'getting used to symptoms' and what 'fine' means. I had a hospital asthma nurse review a couple of weeks ago and she asked me how often I used my inhaler. I was trying to explain the variability I still have - better than it used to be but could only say 'some days none, other days loads,sometimes I need my nebuliser'. I haven't seen the letter yet, but I'm absolutely sure it won't capture any of this and will just say I'm always fine now because I felt ok that day/week.

runcyclexcski profile image
runcyclexcski in reply to Lysistrata

Hi Lysistrata -- I fully agree that NO measurements are not universally useful. In fact, my NO has always been normal -- going back to the days when the NO measurement machine was still in its experimental prototype (and was the size of a refrigerator).

Brochnoscopy was another method they tried on me (I am not sure how deep that goes) and did not pick anything unusual about the airways, either.

Spirometry is obviously an option, and there are portable user-friendly machines that cost 1-2K (I have one). Considering that it took my hospital a year to do a spirometry test, it seems a no-brainer to have one's own spirometer (if asthma interferes with one's life).

Another method I asked about here is airway oscillometry, and my hospital was not interested in trying it.

I guess PF is cheap, it's a piece of plastic, and it works for 90% of people. For the remaining 10% of poor souls, it is the law of diminishing returns: it takes 1000x more costly machines to diagnose inflammation in 10% of people.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to runcyclexcski

Peak flow is cheap and easy and can be done at home by most people, so I can see why it's still widely used, given the alternatives currently. I don't like it, but I have found value in tracking patterns when I can be bothered - which I mostly can't because my consultant isn't interested when I share them. I would like an option that doesn't need charts to show the issue - in the ED, you need something you can just measure, and that non-specialists can easily interpret. I don't think just one peak flow number is that for everyone, but it's easier than the thought of trying to do spirometry when I can't breathe.

You can get simple portable home devices to measure FEV1 for a lot less now, £50-100. Still beyond the means of some people, but not 1-2k which I don't think most people could afford or would spend the money on, no matter how much they might want to measure their airways!

The small electronic ones don't however show much I think beyond FEV1, so you aren't going to get the full range of results from them, plus while they also measure peak flow, a physiologist told me you need a different technique for accurate peak flow and FEV1 with those devices. Also, I've found my peak flow on electronic devices reads higher than on manual, and EDs typically use manual still.

I don't know if the 1-2k ones you mentioned capture more measurements, but even if those became as affordable as the other electronic ones and were viable for home use, and you'd still need to be sure the person is using the right technique and have an easy way for most people to track it and share it with their doctors. It's also not measuring inflammation still - the effects of it, possibly, but not what is actually going on as an underlying mechanism to cause airways to narrow. The gadget I was testing out was intended to be a better version of FENO in that it gave you warning that things were heading downwards by measuring different factors. For some people, peak flow does do that of course, at least effectively enough for what they need.

I've done airway oscillometry. Problem was the lack of context (a human factor - also an issue for spirometry I find in practice). Also, the doctor doing it admitted that while similar factors to spirometry would affect 'normal' values for oscillometry (height, sex, age and possibly others), they didn't yet have enough data to build up a good picture of expected normal values for a given person, let alone any other factors that might affect it. As someone who's outside the normal range for peak flow and formerly for spirometry, that didn't make me hopeful that it would turn out to be useful. Plus currently it requires a lot of equipment still.

runcyclexcski profile image
runcyclexcski in reply to Lysistrata

Re: oscillometry -- I did not realize they still lacked "normal" expected values, that would indeed make it mostly useless!

The gadget I had for spirometry measured the time vs flow curve, with FEV1, 25-75% values etc, and the numbers were pretty close to what I was getting with a big machine. That machine was bought in ~2008 for $2.5K, I would guess there are now cheaper knock-offs (just like oxygen meters used to cost $400 back in those days). I suppose, if one has one's own baseline, one can use the numbers to track one's condition. And I agree... doctors won't be happy with self-measured spirometry tests.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to runcyclexcski

I think they have some to be fair, but my impression was they lacked a large dataset. Mind you, I feel there needs to be more education for healthcare professionals about what 'predicted' means in the context of measuring things like peak flow. Population average does not mean the person in front of you absolutely must have those numbers, but it's treated in a very binary way.

runcyclexcski profile image
runcyclexcski in reply to Lysistrata

>>> 'predicted' means in the context of measuring things like peak flow. Population average does not mean the person in front of you absolutely must have those numbers, but it's treated in a very binary way.

I teach pre-med students, and their understanding of maths and statistics is pretty dodgy. I doubt it gets much better when they become GPs... at least in my area of the UK.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to runcyclexcski

I'd be happy if research professors in tertiary care seemed to understand that concept better than some of them do! Or triage nurses, especially when I can't talk properly. I wanted to explain to one in simple terms that it's a bit like height when he told me my best was impossible and used the predicted, but lacked breath and he wasn't listening. Yes, the average woman in the UK is about 4 inches shorter than me (I think), but that doesn't mean it's impossible for me to be 5'8" or another woman to be 4'11". Similarly, an average 5'8" woman my age probably won't have my best peak flow (even if she has no respiratory problems), but it doesn't mean *I* can't have that best!

runcyclexcski profile image
runcyclexcski in reply to Lysistrata

>>>he told me my best was impossible

Eyeroll. When my AE doctor tried this on me, I said that I am two standard deviations away from the mean which is a chance of 1 in 20, which was his own success rate at getting to the medical school. So if my PF was impossible, his medical degree was impossible, too (these were the words I used... in between breaths).

CANINE12 profile image
CANINE12 in reply to runcyclexcski

Thank you for replying to my thread, it makes me feel less alone when I hear other people's experiences.

Unfortunately I don't have raised eosinophils so far.

I read somewhere before or heard it before about inflammation in the small airways not registering on peak flow or FENO.

hilary39 profile image
hilary39 in reply to runcyclexcski

This is interesting about the small airway inflammation. I have the same theory for why I can be miserable in a terrible flare and still have an ok peak flow.

I’m in a flare right now and yawning and uncomfortable but my peak flow is 500 (I’m a 42 year old 160 cm woman so it should be 420 according to charts).

I’d love to learn more about this topic. Do you remember any of the articles you read in particular? I’ve googled it and haven’t found much-

Thank you!

runcyclexcski profile image
runcyclexcski in reply to hilary39

scholar.google.com/scholar?...

To get the PDFs, get the DOI of the paper and try sci-hub.

Getting treatment specific to small airways has been difficult for me though b.c. there are not many options, and one needs to find a doctor whose academic research focuses on small airways.

hilary39 profile image
hilary39 in reply to runcyclexcski

I am an American living in France and am hoping to see Dr. Sally Wenzel in Pittsburgh the next time I'm home. She specializes in this small airway research as well as the different phenotypes of asthma. She has campaigned to give severe asthma its own name which is a v interesting idea. You might be interested in some of her work. I have not been able to find a doctor in France who specializes in any of this-

profiles.dom.pitt.edu/paccm...

runcyclexcski profile image
runcyclexcski in reply to hilary39

How is she going to manage your treatment in France? I can also recommend Homer Boushey's department at UCSF, since you are flying across the pond anyway, it's an extra 5 hrs :) But ultimately they all have the same tools at their disposal. Well, OK, in the USA and Germany they also do desensitization (aka allergy shots). I believe the latter made the difference for me in the USA. Have you looked in Switzerland? I am going to try Swiss options.

hilary39 profile image
hilary39 in reply to runcyclexcski

Oh interesting! Thanks for the recs! I will look into Homer Boushey.

I was thinking of seeing Dr. Wenzel just as a consultation, not to oversee me as a patient. I have a million questions my doctors here haven't been able to answer so it would just be a long q&a basically :)

I had allergy shots for ten years in the states that worked pretty well but they don't do that in France, they just do the sublingual drops which don't really work with cat and dog allergens apparently (those are my biggies).

Curious to hear what you find in Switzerland--keep me posted! :)

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to hilary39

Ooh - hope you get on well with Dr Wenzel, please share anything you're happy to! I've come across her work and the way she describes asthma is very interesting, as she's not restricting her focus to certain types as so many do. There's still a relative lack of attention and understanding here in the UK to different types of asthma, both in terms of underlying biology and in how people present, which seems to be similar across different biological mechanisms.

I was just in hospital and they wouldn't stop going on about my FENO and my eosinophils even though they know my asthma isn't that kind so these measures are not very helpful. I kept saying I get FENO can be useful for some people but it hasn't been for me given I can be admitted at 16 and walking around fine at 55. She just kept explaining how it works to me. i would love my team to be more open to different markers.

hilary39 profile image
hilary39 in reply to Lysistrata

Interesting how it's so country-specific. In France they've never measured my FENO. Instead they focus almost entirely on the spirometry.

What kind of markers do you think a team should look for? I never thought about that before.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to hilary39

Well, I do have some sympathy with asthma teams as effective markers can be hard, especially in non-eosinophilic asthma - I know from work that's an ongoing question without easy answers.

But then that needs to be acknowledged - there's no point in using markers which consistently have been shown not to be helpful for a patient. It's like deciding there's nothing wrong with a 12 year old's height because they're the same height as their totally normal, average height for their age 6 year old sibling!

I would like to see more acknowledgement that we're individuals, with my team. I don't know what the best marker is for me but I feel like if they were willing to work with me and listen, we could come up with something. At the moment it feels like they're trying to squeeze me into a box because it's easier, and the fact I don't fit in it so it isn't actually helpful, isn't acknowledged.

I keep getting 'objective markers' and 'evidence base' thrown at me. Yes thanks doctor, I know what those mean, but they're not questioning whether I'm the same as the patients those markers are based on, or how the studies were done. And even within that there are natural variations in how people respond. Just like there are in height or foot size, or in peak flow as I mentioned, where the statistics often get misinterpreted as 'every woman your height and age must have this peak flow.'

My team does also use spirometry, but that has the same issues as peak flow - population averages, and often using one cutoff for obstruction when that varies by age, height and sex even as an average. Mostly I find the spirometry is taken into account if it supports the team's point, but not if it doesn't. Another example where I would like it to be acknowledged how it works for me as an individual - I was laughed at by the asthma nurse when I suggested getting readings when I felt very well, as a baseline so they can see what I can do - previously ai have done higher than my predicted there too. But that's done for peak flow, and it would mean they have a point of comparison for me.

CANINE12 profile image
CANINE12 in reply to Lysistrata

Wow I never expected this thread to be replied to 8 months later. 🙂

I'll have to look up Dr Sally Wenzel, looks interesting.

runcyclexcski profile image
runcyclexcski in reply to hilary39

>>>Curious to hear what you find in Switzerland--keep me posted! :)

I will let you know! It's too bad they do not do shots in France. If you want allergy shots, they also exist in Germany; Germany is closer to France than the USA. I am right at the border, so I will let you know if I manage to get them here. It's disappointing that they only go with what works with the "average patient".

Poobah profile image
Poobah in reply to hilary39

Thanks for sharing about Dr Wenzel - going to read up about her work.

hilary39 profile image
hilary39

Even when I am in a terrible flare my peak flow often doesn't change. I posted a question about this on a Facebook asthma support group which has thousands of members and a bunch of people posted saying they have the same thing just in case that's any comfort (even if pulmonologists and ER doctors don't understand that that's possible!)

I have an appt tomorrow to see a severe asthma specialist and plan on asking her this exact question because it is frustrating when I'm trying to get treated during a flare and bump up against the steretype that all severe attacks are marked by a big drop in peak flow + loud wheezing.

I usually don't have either yet I can have a six week severe exacerbation where I can barely breathe after a minor exposure to something so I don't know what that is if not severe allergic asthma!

Birthday60 profile image
Birthday60

peak flow is a classic measure for asthma as it’s the ability to breath out that is the issue. If peak flow is not impacted then breathlessness council be simply panic attack of lack of fitness.

Lysistrata profile image
LysistrataAdministratorCommunity Ambassador in reply to Birthday60

I realise this is from 8 months ago but not seen before - replying as others may read.

Agreed that asthma is primarily about the out breath, at least to start with (later on in an attack both would be affected). But peak flow is definitely not the only measure of how well you breathe out - anyone reading should look at the discussion further up this thread as there are other factors involved.

Peak flow as discussed above doesn't measure small airways - and to some extent I suspect it's used more because it's the easiest measure for home use. It's also more useful as a pattern a lot of the time, measured against a person's own best and how they respond (eg the peak flow looks ok but after someone takes reliever it improves much more, suggesting there was asthma even if the first number wasn't too bad).

The predicted values are also just population averages for people of a certain height, age and sex - it doesn't mean an individual will necessarily have that, it's just a starting point for when people don't know their best. My predicted is only 71% of my best.

It should also be taken in context - would be a serious mistake to assume someone isn't having asthma issues and it's just panic or unfitness based on peak flow alone, especially using predicted. I have had severe attacks by other measures when 'only' in my yellow zone - if you measured the attacks only by peak flow they would be moderate, but by other measures they were severe.

Dogsbody2all profile image
Dogsbody2all

I'm another one whose peak flow doesn't drop when I'm having symptoms. I have a best of 610, typically 580-590. The predicted average for my height, age and sex is 420.

I haven't been referred to a consultant - yet. I think I'm gonna push for that. I take DuoResp 160/4.5 two puffs twice daily, fexofenadine 120 one tablet twice a day, Montelukast, and a nasal spray twice a day. That's on good days. At the moment I can't seem to get off the added in extra puffs of DuoResp at lunchtime (making two puffs three times a day).

sciencepotato profile image
sciencepotato in reply to Dogsbody2all

another one with peak flow 550 and doesn't drop below 450-500 even during chest infection when paramedics hear large wheeze across the chest and I'm struggling to move about. A few prednisolone tablets relieve all my breathlessness.

I'm under severe asthma clinic at the moment and they are booking me in for mannitol challenge test to assess the inflammation in the lungs.

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