Best time for taking Peak flow

I'm sure I should know this really but I'm not certain. After a few month break, my asthma is rearing is head again and so I want to collect some Peak flow data incase I need to see the Gp,(not that peak flow is usually a good indicator for me!) I haven't properly done it for a few years, normally just blowing every now and then and checking it's Ok, or checking it if I'm feeling tight but I don't record it.

So I wanted to know when is the best time to record Peak flow?

Also do you record inhaler usage as number of puffs or times used eg yesterday I had to use it 8 times at 2 puffs each time, do you record as used inhaler 8 times, or as 16puffs? And how do you convey how soon after one another they were taken? 16 puffs over 24 hours isn't that bad, but 6 of those were taken within 5 mins of each other as I couldn't catch my breath.

I know it's semantics really but I often don't get taken seriously because I don't wheeze, so I need to make sure I get my point across to the Gp.

Thanks in advance

12 Replies

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  • Hi there,

    do you have a smartphone? There are free apps for iPhone and Android that help you track your PF, reliever use, triggers etc.

    If you don't then I would just record it in a spreadsheet or on a piece of paper.

    As a minimum (for your purposes) it's worth recording your PF first thing in the morning and last thing at night, and once during the day when you're feeling at your best. When I was tracking mine for my GP and consultant I took it several times per day.

    I record each puff (it is allowed to take odd numbers of puffs of your inhaler!). Do you use a spacer? The tighter you are the more benefit there is to using one, obviously. You can do tidal breathing on single puffs, or you can multi-dose into the spacer and then do tidal breathing. How ever you do it, it's worth remembering that the worse your attack the less inhaler gets in, so 10 puffs in a bad attack might only deliver the same amount of drug to your lungs as 2 puffs when you're just mildly tight.

    I hope things get better again for you soon - hopefully it's 'just' the weather / cold season / xmas trees etc causing you problems and will settle again soon.

    Cx

  • Thanks for your reply Curiouser.

    Yeah I do have a smart phone, I did look at the apps before but none of them where quite right for me, some you couldn't go back and edit so you had to record inhaler usage as you do it or not at all which isn't really practical. I'll probably be best recording it all manually, although the online ACT test is quite good for prompting you to truely think about your symptoms.

    Is there a peak/ trough in daily pf, should i avoid these times? I also use seretide so will the laba still in theory be making my pf artificially high during the day?

    I will start to record individual puffs then, I think sometimes the Gp had thought I've not been using much when looking at times taken, when actually I've had twice as much.

    I do use a spacer when possible, to be honest when my chest is really tight I struggle to take anything if I don't have my spacer. I also find that side effects are less with a spacer too especially when needing a lot.

    I hope things get better again for you soon - hopefully it's 'just' the weather / cold season / xmas trees etc causing you problems and will settle again soon.

    Cx

    Thank you, yes I too hope it's just a blip as before my symptoms went away last year,my GP wanted me on low dose steroids or theophylline which I'd rather avoid!!

    Hope you're keeping well xxx

  • I know There is diurnal variation in pf but when are the natural peaks and troughs?

    lungs are feeling twitchy today, don't know if weather partly to blame!! Peak flow is 70-75% but want to check at the natural Peak incase I'm missing it and hitting the troughs so it's looking artificially lower.

  • Hi Butterfly,

    Sorry to hear you are going through a rough patch again.

    I was told by an auk nurse that the best time to take a peak reading is about 4/5 in the afternoon. This is also the time I usually see the doctor and tend to get quite good readings then!

    When gathering data for GP, I also took it before and after reliever (not when having an attack but just a bit tight) which was helpful in highlighting reversibility.

    With inhaler use, I wrote it down the time of day and the number of puffs with any extra information (again only while gathering information). This was quite useful to show the cons to help her see that I need it more at night and when I have been outside (it was in the summer).

    Take care

  • Thank you for your reply kayla

    I was told by an auk nurse that the best time to take a peak reading is about 4/5 in the afternoon. This is also the time I usually see the doctor and tend to get quite good readings then!

    When gathering data for GP, I also took it before and after reliever (not when having an attack but just a bit tight) which was helpful in highlighting reversibility.

    With inhaler use, I wrote it down the time of day and the number of puffs with any extra information (again only while gathering information). This was quite useful to show the cons to help her see that I need it more at night and when I have been outside (it was in the summer).

    Take care

    This is great Thank you, I wouldn't normally take my pf at this time so am going to miss my best possible daily reading. I will add this to my measuring regime and see what data I get. I always get better readings at the Gp, I've often thought I should take my meter with me incase there's a difference in them!

    That's a good point about before and after reliever too, I know my spirometry 4 years ago didn't show much reversibility but I know in reality when symptomatic, I do show reversibility.

    I don't think there's any particular pattern in my symptoms but perhaps recording information as you've said, might highlight something. I know yesterday when walking to work it was cold and windy and I was walking faster than I ought to because I was a little late and my chest was tight, and after being inside for 5-10mins my chest was burning, i was SOB and I was coughing so I don't know if that was the cold wind or the fact I was walking quite fast?

    I'm hoping this is just a little blip and I won't need to see the Gp but i'd rather be prepared and especially that at this time last year I ended up with lots of chest infections ;-(

  • Hi Butterfly, I always take mine twice daily, 12 hrs apart - immediately before having my inhalers. This gives you a reading of what your lungs are doing, rather than what the inhaler dose is doing to them if that makes sense (advice from resp consultant and resp nurse). i.e. it gives a baseline. These are the readings which are used to manage my medications, and yes my peak flow may go up slightly during the day (not much at all tbh) but that would be as a result of the inhalers as much as anything else. Whatever you do do, ensure they know the times you do it so they can take meds etc into account.

    When I go to papworth, I am not allowed to take my inhalers that morning because I have breathing tests and they want to know what my lungs are doing, not the effects of the inhalers - same principle.

    BTS guidelines recommend twice daily over at least two weeks.

  • Thank you nursefurby.

    Since this flare up started, for the last week or so, I have been measuring before my doses of seretide but they've been generally really quite low for me (lowest 68%, highest 95%, averaging 72-75%) and I didn't' know if they really are just low, or if in the past I've meausred at the peak of diurnal variation. I guess what you are saying is that provided you always record PF before seretide you can compare good times with bad times knowing that the time is always the same. So I guess measuring at 4/5pm might be artificially high due to a) circadian peak AND b) effect of LABA in the seretide?

    Interestingly then, when I see the GP at 10am telling him my PF is low and I'm having symptoms, and I actually blow a good PF why do I get told I'm fine when they haven't taken into account that I took my seretide 2 hours ago? grrr

  • Yup that's it.

    if you measure before inhalers twice daily you get consistency and can see the difference between good and bad times. At best, mine will be 300 twice daily, at worst 220 twice daily. You're absolutely right about peak flow at the GP, you either need to tell them that it's AFTER the seretide, or don't take your morning dose until after you've seen them! They need to take it into account. x

  • Ok great Thank you. I shall keep on with the 'before seretide' monitoring, in addition include before and after ventolin readings and keep my fingers crossed I don't need to see the Gp!!

    out of interest, what is good improvement after ventolin? Like I mentioned earlier, I was told 4 years ago that my response wasn't that great so am interested to see what it should be vs what I actually see.

  • Depends on the individual and the severity of exacerbation I think. I'm the wrong person to ask as I am now deemed to be COPD with minimal reversibility.

  • significant reversibility for peak flow is usually considered 60 L/min or 20% improvement . But it is also important to note changes in symptom levels because PEF is only one of many measures of lung function and doesn't always reflect the changes in your lungs that are creating the symptoms. Sometimes I can be symptomatic when PEF is 85-90% (tight, couging, SOB) - there isn't a lot of room for improvement in PEF at that point, but ventolin can still make a big difference in the symptoms.

    As for when to check - depends on what question you are trying to answer:

    - what is my baseline lung function without reliever? (i.e. am I getting better or worse?): as nurse furby says - before meds is best (but if you are a heavy ventolin user may not be possible). Note that some asthmatics have very good baseline lung function and jumpy lungs - so ""baseline"" doesn't always measure what is needed for them.

    - what is the impact of SABA (ventolin, bricylin)? : before use and 5-15 minutes after - but if you are likely to get distracted , just do it right after use - ventolin works very quickly so you should see some effect almost immediately .even if it isn't as large as it would be if you waited.

    - how well does pf correlate with symptoms? - check when there are major changes in symptom levels - both when you are feeling really good/much better and when you start feeling much worse. It is important to do both so you know what goes along with ""good"" and not just what goes along with ""bad"".

    - do I have a diurnal rhythm? - not everyone does but a large one signifies asthma and an increasing one over a series of days signifies a developing loss of asthma control - for that you want to catch your best and worst times - Curiouser's advice about once in the midle of the day when you are feeling really good is a good way to capture that.

    - overall jumpiness/evidence of variable obstruction? - all of the above - if you are trying to demonstrate that lungs are able to have wide swings in PEF then it really doesn't matter where the swings come from - diurnal rhythm, symptoms, reliever - normal healthy lungs don't have highly variable PEF for any of those reasons - regardless of reliever use or time of day the variation is usually less than 8% per day. If measuring 2x a day , > 8% is considered abnormal. If measuring 4x or more a day > 20% daily variation is considered abnormal. (ATS/ERS 2009 guidelines on asthma control and exacerbations)

    Note: daily variability = (highest - lowest of the day) / (average of high and low) -or- (highest -lowest)/ (highest of day) - not much agreement on how to measure variability - some sources use one , some sources use the other.

    You might also find these two guidelines helpful :

    * ""An Official American Thoracic Society/European Respiratory Society Statement: Asthma Control and Exacerbations: Standardizing Endpoints for Clinical Asthma Trials and Clinical Practice"" in The American Journal of Respiratory and Critical Care Medicine, 2009; 180: 60-99. Available at www-archive.thoracic.org/se... .

    * ""Offical ERS Statement: Peak expiratory flow: conclusions and recommendations of a working party of the European Respiratory Society"" in Eur Respir J 1997, 10: Suppl. 24, 2s-8s. Available at spirxpert.com/spirxpertnl/E... .

  • Thank you for you reply Beth,

    significant reversibility for peak flow is usually considered 60 L/min or 20% improvement . But it is also important to note changes in symptom levels because PEF is only one of many measures of lung function and doesn't always reflect the changes in your lungs that are creating the symptoms. Sometimes I can be symptomatic when PEF is 85-90% (tight, couging, SOB) - there isn't a lot of room for improvement in PEF at that point, but ventolin can still make a big difference in the symptoms.

    Yes agree with this Beth, sometimes my PF is low all day and I feel fine, then another day I feel terrible but it's the best PF I've had for sometime, and ventolin does very little to my PF, however symptomatically I feel much better. I think the reversibility bit was for my own interest really as I know I usually respond well to ventolin symptomatically but wondered what the figures 'should' say to correlate with this. And for clarification, the reversibility on a spirometry test looks at 10 puffs through a spacer wait 15 minutes, is that correct? I know my spirometry was fewer puffs and she waited only a few minutes (probably why I hadn't shown much reversibility!) Needless to say figures before and after ventolin today with only reasonably mild symptoms improved by 85L/min which equated to 21% improvement after only 2 puffs.

    As for when to check - depends on what question you are trying to answer:

    I guess I'm not sure really what I want to show, I'm pre-empting a visit to the GP and would like to be armed with some objective data before I'm fobbed off whith 'your chest is clear therefore you're fine'

    - what is my baseline lung function without reliever? (i.e. am I getting better or worse?)

    So I guess this would be useful although I don't have any data from before this flare that would show a decline

    - what is the impact of SABA (ventolin, bricylin)?

    This is for my own interest really

    - how well does pf correlate with symptoms?

    I know this doesn't always correate!

    - do I have a diurnal rhythm?.

    Again my own interest really, didn't know if I was always getting low results because I was hitting a diurnal trough, I have started collecting some data from during the day but difficult when I've been using ventolin through the day, it does tend to be higher (by 18-21%) than morning/night though.

    - overall jumpiness/evidence of variable obstruction? - all of the above - if you are trying to demonstrate that lungs are able to have wide swings in PEF then it really doesn't matter where the swings come from - diurnal rhythm, symptoms, reliever - normal healthy lungs don't have highly variable PEF for any of those reasons - regardless of reliever use or time of day the variation is usually less than 8% per day. If measuring 2x a day , > 8% is considered abnormal. If measuring 4x or more a day > 20% daily variation is considered abnormal. (ATS/ERS 2009 guidelines on asthma control and exacerbations)

    I guess the fact that reliever use has improved PF by 21% today, and that afternoon readings have been 18-21% higher than morning/night, this confirms, along with my symptoms and ventolin usage, that my lungs are misbehaving!!

    Thank you for the guidlines, these have been interesting reading too, although I've only scanned through for now, will look better tonight!!

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