Richard Johnston

A report of a patient’s complete set of PFTS came across my desk yesterday. There were a lot of inconsistencies in the report and I ended up looking at the raw data for every single test. Whe…

Patients are advised not to smoke prior to DLCO testing, primarily because it increases carboxyhemoglobin. The effect of COHb on DLCO has been well studied, but COHb is not often measured before DL…

I was recently contacted by a physician looking for an illustration or diagram to help make gas exchange and DLCO more understandable. We’ve all seen the diagram of the alveoli with a capilla…

This is not something I have any real influence over because the tests ordered on a patient’s first visit to the PFT lab are going to be determined by the ordering patterns of the referring p…

I’ve had a bug lately about lung volumes and I guess that today is no different. A report with some odd lung volume results came across my desk and I’ve spent some time trying to figure…

Although the technology used to perform the single-breath DLCO test has improved since it was first developed in the 1950’s the essential concepts and equations have not changed significantly…

I have been researching different pulmonary function topics for quite a few years. The medical libraries I’ve frequented were, of course, originally all paper-based and to be able to find an …

Just when we thought it was safe to go back in the water, we’ve run into another N2 washout-related problem. Although it probably affects the TLC and RV calculations in a minor way, it was ac…

Re-breathing DLCO may not be well known because this technique has not been used in routine clinical testing. It has instead been primarily used to research diffusing capacity during exercise becau…