A friend recently sent me the links to several YouTube videos on pulmonary function testing. I’ve spent some time off and on over the last year looking at YouTube videos and in particular I’ve been looking for ones that can be used as part of technician education. Maybe I’ve set the bar too high but…
The use of Z scores to report PFT results, both clinically and for research is occurring more and more frequently. Both the Z score and the Lower Limit of Normal (LLN) come from the same roots and in that sense can be said to be saying much the same thing. The difference between the two…
A couple weeks ago I was asked whether it was safe for a patient with an abdominal aortic aneurysm (AAA) to have pulmonary function testing. My first thought was that it was probably unsafe but after a moment or two of thought I realized that I hadn’t reviewed the subject for a long time. When…
The 2005 ATS/ERS standards for assessing post-bronchodilator changes in FVC and FEV1 have been criticized numerous times. A recent article in the May issue of Chest (Quanjer et al) has taken it to task on two specific points: The article points out that the 200 ml minimum change requires a proportionally larger change for a…
A very strange spirometry report came across my desk a couple of days ago. Observed: Predicted: %Predicted: FVC: 3.07 0 29767 FEV1: 2.15 0 37586 FEV1/FVC: 70 71 101% My first thought was that some of the demographics information had been entered incorrectly but when I checked the patient’s age, height, gender and race all…
Last week I was reviewing the exercise test results from a patient that appeared to have a relatively straightforward cardiovascular limitation when I noticed the patient also had severe anemia (Hgb = 7.1). Once that fact came up it was no longer clear the patient actually had a cardiac limitation at all. First the results:…
I’ve mentioned before that my lab’s database goes back to 1990, so we now have 27 years of test results available for trending. At least a couple times a week we have a patient who was last seen 10 or even 20 years ago. When I review their results I try to see if there…
Inspiration and expiration usually take different lengths of time, with inspiration almost always being shorter than exhalation. This is due to both to the physiology of breathing and to the pathophysiology of disease processes. During incremental exercise testing there are usually patterns to the way that inspiratory and expiratory times change and these are occasionally…
After a couple years of waiting for the new methacholine standards to be released “any day now”, they were finally published in this month’s issue of the European Respiratory Journal. The standard is an open access article and can be downloaded by anyone. The length of time taken to develop the standard was acknowledged and…
Inspiratory and expiratory flow rates are a function of driving pressure (i.e. the pressure difference between the alveoli and the atmosphere) and airway resistance. For this reason it would seem that airway resistance should be one of the most commonly performed pulmonary function tests but instead it is the outcome of airway resistance and driving…