Talk:Spirometry

Normal ranges
could we have some normal ranges please? —Preceding unsigned comment added by 77.99.219.14 (talk) 13:48, 13 March 2008 (UTC)

Population studies differ on this point, due both to differences in the studies themselves, non-identical populations that are looked at, and the fact that different "races" actually are statistically different. Different does not imply "superior". The lung is an "optimal" organ. Any changes that make it better at one thing make it worse at another. % predicted is better thought of as % of average. 95% of healthy people will fall within a 40% range of values - or plus minus 20%. But if you have lungs that are 120% of average, and you loose 1/3 of your lung to disease, statistically, you are still within the normal statistical range (80%). Interpretation must take into account the patient's symptoms, and an x-ray or cat scan of the lung (conventional MRI's do not image the lung usefully). The primary determinant of normal lung size is height.

PEF - why so early?
Very nice article.

Does anyone know why is it that the PEF (peak expiratory flow) occurs so early?

expiration is due to the elastic forces of the lung. just like a baloon deinflates faster at the start, so do the lungs, since flow depends on the elastic surface tension of the lung.

Other pulmonary function tests
Anyone able to writ about other pulmonary function tests? I was interested in more information about DLCO, and the differential diagnosis of abnormal values in the DLCO. Ksheka 22:00, 4 August 2006 (UTC)

Photo?
I've added photos of Peak Flow Meters to the Peak Flow Meter article. If it is relevant to this page, then please can someone add them here too? Thanks --Tomhannen 21:59, 25 March 2007 (UTC)

Can lung function scores be increased by exercises?
Hello, Great info in the article.... Is there a way for a person to increase FVC and FEV1 through some type of "lung exercises"? (January 2008) —Preceding unsigned comment added by 74.34.101.149 (talk) 13:20, 19 January 2008 (UTC)

To some extent yes - particularly activities which cause you to exercise your intercostal muscles and, as stronger intercostal muscles will improve your ability to force exhalation. Also, similar exercises cause your lungs to become more compliant thereby increasing their volume.

Ironically, one thing that has been proven to do both of these is smoking. Young smokers generally have superior FVC and FEV1 values, as having to forcibly suck air through a tiny cigarette filter is good exercise. However, in the long run smoking causes a world of damage to your respiratory system - so is definitely not worth the trade off as for most people this superior respiratory ability is short lived, and their lives end up being cut even shorter. —Preceding unsigned comment added by 118.92.208.254 (talk) 13:49, 31 October 2009 (UTC)

I only mentioned to smokers that their lungs measure a bit better than the actual health of their lungs; not that smoking improved anything. --Heli doc (talk) 20:04, 13 September 2012 (UTC)

Spirometry Test Values and Flow-Volume Loop diagram
Hi, I have some confusion. From the table FEV "is the speed of the air moving out of your lungs at the beginning of the expiration, measured in liters per second." Shouldn't it be "is the PEAK speed of the air moving out of your lungs at the beginning of the expiration, measured in liters per second."? —Preceding unsigned comment added by Haimmelman (talk • contribs) 15:28, 15 April 2009 (UTC)
 * I do believe that it is correct as is. The term you are looking for is peak expiratory flow (PEF). Tyrol5   [Talk]  14:55, 20 April 2009 (UTC)

I believe you're getting FEV and FEV1 confused. FEV is the total volume, measured in liters (not litres per second), that your lungs can hold (not including dead space volume). FEV1 is the volume ejected after just one second, which is also measured in litres and not litres per second, which although it is indicative of a rate it is not the same thing as this is a measure of to total volume exhaled in 1 second which you could assume to be the same as the subjects exhilation rate per second, but as It is not guaranteed that the subject was exhaling at their peak rate for the entirety of that second you instead get something more line an average rate. Hence the distinction between FEV1 and PEF. —Preceding unsigned comment added by 118.92.208.254 (talk) 14:00, 31 October 2009 (UTC)

DLCO and TLC
Should not be in Spirometry page because they are not measurable by any spirometry test (FVC, SVC, MVV,..) They are measured by other PFT tests but not by spirometry.

--Toce (talk) 20:09, 25 October 2009 (UTC)

Spirometer printout image


I think this image needs attention to two issues before reinsertion: Mikael Häggström (talk) 09:26, 14 March 2010 (UTC)
 * Can it be confirmed that is is not under copyright?
 * It needs to be larger, because the numbers are currently not clearly seen. It tricks readers into believing that there actually is a larger image by clicking on it, but there isn't.

Someone (presumably an employee of BTL Medical) keeps on removing the printout and putting up a BTL printout which does not show as much information as the first printout (the one with the yellow smiley face on). You can contact the website http://www.advancedmedicalengineering.com and then go to contacts to email the owner of the photo. They will verify that permission is granted for it to be on Wikipedia. —Preceding unsigned comment added by Johnvanzyl (talk • contribs) 21:51, 26 May 2010 (UTC)

Error in image
Hi guys,

There is a flaw in the first image explaining the flow-volume loop: it appears as if FEV1 (the yellow zone) is atteined in the first 10% of the FV loop. Clearly this is not the case (if it were, the FEV1/FVC ratio would be only 10%...). The yellow zone should comprise around 80% of the expiratory FVC loop. —Preceding unsigned comment added by 83.101.95.37 (talk) 14:05, 2 August 2010 (UTC)

Hi, on the same graph the parameter names are wrong. It is not FEV25, FEV50 etc., but this is FEF25, FEF50, ... OR an alternatively used name is MEF75, MEF50, ... Same for the inspiratory curve. —Preceding Reinstaedtler (talk) 07:20, 15 September 2010 (UTC)

Significance of FEF25-75
"FEF 25–75% or 25–50% gives an indication of what is happening in the lower airways. It is a more sensitive parameter and not as reproducible as the others. It is a useful serial measurement because it will be affected before FEV, so can act as an early warning sign of small airway disease. In small airway diseases such as asthma this value will be reduced, it could be less than 65% of the expected value."

I'm having a little trouble sourcing the details of this. I've found a "year-in-review" sort of article (doi:10.1016/j.jaci.2010.11.018), the primary investigation that the review article cites (doi:10.1016/j.jaci.2010.05.016), and another correspondence tying it to allergic rhinitis (doi:10.1016/j.jaci.2010.10.053). However, ACP Medicine (March 2010) states: "Although the earliest evidence of obstruction can be found in a reduction in the instantaneous flows in the middle VC (FEF25-75) or late VC (FEF75), these are nonspecific findings of uncertain clinical significance. The wide variability of FEF25-75 measurements in normal individuals has made this an unreliable indicator of disease, and current recommendations are to not use this measurement to determine disease status."

The articles in support of using FEF25-75 are more recent (September 2010 and February 2011), so it's possible that this may be new, good information. However, until such time as that's been established, I think the language in the article here should be a little more tempered.

I'm going to change it to read: "Recent research suggests that FEF25-75% or FEF25-50% may be a more sensitive parameter than FEV1 in the detection of obstructive small airway disease. However, in the absence of concomitant changes in the standard markers, discrepancies in mid-range expiratory flow may not be specific enough to be useful, and current practice guidelines recommend continuing to use FEV1, VC, FEV1/VC and FVC as indicators of obstructive disease." Blahdenoma (talk) 15:45, 29 April 2011 (UTC)

I'd like to see this information incorporated into the Article. --Heli doc (talk) 20:09, 13 September 2012 (UTC)