Richard Johnston

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 …

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 spirometry and lung volume tests but for …

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 the tid…

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 my lab than at …

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 the way the patient pe…

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 lung at the …

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 of pulmonary v…

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…

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 able to enroll in this stud…