The ratio-nal approach to predicted TLC
I’ve been reading Miller et al’s Laboratory evaluation of Pulmonary Function which was published in 1987. That was an interesting time since PFT equipment manufacturers had mostly trans…
I’ve been reading Miller et al’s Laboratory evaluation of Pulmonary Function which was published in 1987. That was an interesting…
28 Feb 2016 February 28, 2016 by Richard Johnston • Leave a comment
Underutilized spirometry, missed opportunities
A friend is taking her father to a PFT lab (2500 miles away from where I am the moment so I couldn’t go along with them) because he has been…
A friend is taking her father to a PFT lab (2500 miles away from where I am the moment so…
21 Feb 2016 February 21, 2016 by Richard Johnston • Leave a comment
Turbine spirometers
Turbine spirometers have been around in one form or another for well over a hundred years. The accuracy of the early versions of this type of spirometer was poor, partly…
Turbine spirometers have been around in one form or another for well over a hundred years. The accuracy of the…
16 Feb 2016 February 16, 2016 by Richard Johnston • Leave a comment
Graphical Analysis of Flow-Volume Loops
I’ve been thinking a bit about the shape of flow-volume loops lately. In part this has been about ways to accurately describe them in reports; in part speculation about the…
I’ve been thinking a bit about the shape of flow-volume loops lately. In part this has been about ways to…
11 Feb 2016 February 11, 2016 by Richard Johnston • Leave a comment
The importance of an earnest SVC
A report came across my desk today and at first glance it looked fairly straightforward. There was a mildly reduced TLC and FVC, and although the SVC was slightly lower than…
A report came across my desk today and at first glance it looked fairly straightforward. There was a mildly reduced TLC…
4 Feb 2016 February 4, 2016 by Richard Johnston • Leave a comment
Shunt fraction
I was reading an article recently that made an off-hand reference to the 100% oxygen shunt fraction test. Results from the test were included in the data analysis but the…
I was reading an article recently that made an off-hand reference to the 100% oxygen shunt fraction test. Results from…
27 Jan 2016 January 27, 2016 by Richard Johnston • Leave a comment
6MWT re-visited, now with the MCID!
I often find topics for this blog in a sideways fashion. Recently while searching for something else I ran across an article about the minimum clinically important difference (MCID) of…
I often find topics for this blog in a sideways fashion. Recently while searching for something else I ran across…
20 Jan 2016 January 20, 2016 by Richard Johnston • Leave a comment
Hidden FIVC and FVC. When all the data is relevent.
For the first dozen or so year that I worked in a pulmonary function lab it was with counter-weighted, volume-displacement water-seal spirometers more or less like this: Patients would do…
For the first dozen or so year that I worked in a pulmonary function lab it was with counter-weighted, volume-displacement…
3 Jan 2016 January 3, 2016 by Richard Johnston • Leave a comment
RVD’s and OVD’s can’t mix without the FEV1/FVC ratio
The patients whose reports I review have always been very accommodating. An issue of one kind or another catches my attention and before I know it I find several more…
The patients whose reports I review have always been very accommodating. An issue of one kind or another catches my…
30 Dec 2015 December 30, 2015 by Richard Johnston • Leave a comment
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