It’s after midnight, do you know where your reports are?
After the tests themselves, the second most important thing that a Pulmonary Function Lab needs to do is to report results. Like a tree falling in the woods, if a report hasn’t gotten in fron…
Richard Johnston
Steady-State DLCO, an almost-forgotten technique
Recently I have been reviewing a lot of early pulmonary function research. I’m not feeling nostalgic but I think that re-visiting some of the older methods and technology may be interesting. …
Busted for speeding during an N2 washout
Nitrogen washout lung volumes are still relatively new to my PFT Lab. The number of problems we’ve encountered has decreased substantially but we are still learning some of the idiosyncrasies…
Plethysmography and “trapped air” demystified
Recently I was reading the blog of someone who teaches Pulmonary Function testing and they stated: “…in emphysema and air trapping, the VTG (thoracic gas volume) will be higher than a FRC (fu…
What’s normal about the FEV1/FVC ratio?
The FEV1/FVC ratio is used to estimate the presence and degree of airway obstruction. For well over thirty years my lab has used an FEV1/FVC ratio of 95% of predicted as the cutoff for normalcy. Th…
N2 washout switch-in error
I have been taking a close look at the raw data from all lung volume tests lately in large part because N2 washouts are still relatively new to my PFT Lab and we’re continuing to learn from o…
Height and arm-span
The PFT Lab I am associated with has been making a point of having the technicians re-measure patient height with each visit. Part of the reason for this is that several years ago the medical assis…
Peak VO2 and low body weight
The PFT Lab I am associated with performs cardiopulmonary exercise tests for pre-op cardiothoracic surgery patients with lung cancer. Surgeons have to make a decision to operate or not based at lea…
Plethysmographic Puzzle
This PFT report came across my desk the other day. At first glance it looked wrong because when was the last time you saw a patient with a FRC that was 165% of predicted?