The GLFI TLCO Task Force is open for business
Late in 2012 the Global Lung Function Initiative (GLFI) released their reference equations for spirometry. Although not without some criticism this was an important step towards the development of …
Late in 2012 the Global Lung Function Initiative (GLFI) released their reference equations for spirometry. Although not without some criticism…
26 Jan 2014 January 26, 2014 by Richard Johnston • Leave a comment
What’s normal about DLCO?
The lungs are the gas exchange organ of the body. The mechanical aspects of the lung, which do of course have a bearing on gas exchange, can be assessed by…
The lungs are the gas exchange organ of the body. The mechanical aspects of the lung, which do of course…
2 Jan 2014 January 2, 2014 by Richard Johnston • Leave a comment
Sawtooth pattern on the flow-volume loop
One of the recognized abnormalities of a flow-volume loop is a sawtooth profile due to flow oscillations that are superimposed on either the maximal expiratory or inspiratory flow curve, or…
One of the recognized abnormalities of a flow-volume loop is a sawtooth profile due to flow oscillations that are superimposed…
22 Dec 2013 December 22, 2013 by Richard Johnston • Leave a comment
What’s wrong with this picture?
I had mentioned previously that my PFT Lab has been questioned why the percent predicted Residual Volume (RV) measurements on some research patients were coming out so much lower at…
I had mentioned previously that my PFT Lab has been questioned why the percent predicted Residual Volume (RV) measurements on…
20 Dec 2013 December 20, 2013 by Richard Johnston • Leave a comment
Zero offset in DLCO: system error or patient physiology?
I’ve noticed for a while that there has often been more variance between DLCO tests than I’d like to see. Some of this is of course attributable to differences in…
I’ve noticed for a while that there has often been more variance between DLCO tests than I’d like to see.…
12 Dec 2013 December 12, 2013 by Richard Johnston • Leave a comment
FRC baseline shift affects TLC and RV
The plethysmographic technique for measuring lung volumes determines FRC first and then uses a slow vital capacity maneuver to calculate TLC and RV. FRC is defined as the volume of…
The plethysmographic technique for measuring lung volumes determines FRC first and then uses a slow vital capacity maneuver to calculate…
7 Dec 2013 December 7, 2013 by Richard Johnston • Leave a comment
CO2 response testing, still crazy after all these years.
I’ve had several exercise tests come across my desk lately where the patient had an elevated Ve-VCO2 slope. An elevated Ve-VCO2 slope during exercise is usually taken as a sign…
I’ve had several exercise tests come across my desk lately where the patient had an elevated Ve-VCO2 slope. An elevated…
24 Nov 2013 November 24, 2013 by Richard Johnston • Leave a comment
What does Peak Flow have to do with back-extrapolation?
Well, everything, actually. Surprisingly enough they are intimately related to each other. One of my current projects is to develop specifications for computer software designed to analyze spiromet…
Well, everything, actually. Surprisingly enough they are intimately related to each other. One of my current projects is to develop…
13 Nov 2013 November 13, 2013 by Richard Johnston • Leave a comment
What’s normal about RV and what does this have to do with TLC?
A physician associated with my PFT lab has become an investigator for a device study intended for patients with severe COPD. One of the major criteria for patients to be…
A physician associated with my PFT lab has become an investigator for a device study intended for patients with severe…
25 Oct 2013 October 25, 2013 by Richard Johnston • Leave a comment
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