Richard Johnston

I was reading James Hansen’s textbook on pulmonary function testing (one of my more interesting reads lately) and in passing he mentioned using the VA/TLC ratio as a way to measure ventilatio…

Recently I reviewed a set of completely irreproducible spirometry results. The patient had made eight attempts and the FVC, FEV1 and Peak Flow were different every time. In particular, there were f…

I was reviewing a spirometry report and noticed something odd about the flow-volume loop, or more specifically the tidal loop, and this got me to thinking about what tidal loops can tell us about t…

Recently while reviewing PFT reports I ran across a test from a patient who had been having spirometry, lung volume and DLCO tests performed at regular intervals for the last several years. Compare…

I’ve been reviewing my CPET textbooks trying to get a better idea of how to differentiate between different cardiovascular limitations. The other day I ran across an article on a related subj…

Obesity has become far more commonplace than it was a generation ago. The reasons for this are unclear and have been attributed at one time or another to hormone-mimicking chemicals in our environm…

I thought I was done with lung volume issues for at least a little while but a short time ago I was reviewing a report from another PFT lab and I ran across something that didn’t seem to make…

I was reading James Hansen’s textbook on pulmonary function testing and ran across a spot where he made a minor criticism of the NHANESIII (Hankinson et al) reference equations for the FEV1/F…