Creepy decimal points
This is one of my pet peeves. It started for me back in the 1970’s when the Intensive Care Units where I was working were evaluating thermal dilution cardiac output…
This is one of my pet peeves. It started for me back in the 1970’s when the Intensive Care Units…
15 Oct 2014 October 15, 2014 by Richard Johnston • Leave a comment
When an Inspiratory Volume really isn’t inspiring
I always like it when a patient does something during a test that makes me have to think about the basics of the test and what effect an error will…
I always like it when a patient does something during a test that makes me have to think about the…
4 Oct 2014 October 4, 2014 by Richard Johnston • Leave a comment
Ve-VCO2 slope: Just to AT or all the way to the peak?
We’ve had some questions lately about some of our CPET guidelines. These questions were informational in nature not confrontational but they served to remind us that the reference values we…
We’ve had some questions lately about some of our CPET guidelines. These questions were informational in nature not confrontational but…
26 Sep 2014 September 26, 2014 by Richard Johnston • Leave a comment
Exercise Oscillatory Ventilation
Recently I was trying to make some sense of an exercise test report that had come across my desk. Numerical results on our CPET reports are averaged over 30 second…
Recently I was trying to make some sense of an exercise test report that had come across my desk. Numerical…
20 Sep 2014 September 20, 2014 by Richard Johnston • Leave a comment
COPD, BD and IC
The ATS/ERS recommendation for assessing the response to bronchodilator is based solely on changes in FEV1 or FVC. An FEV1 that does not improve significantly following bronchodilator inhalation is…
The ATS/ERS recommendation for assessing the response to bronchodilator is based solely on changes in FEV1 or FVC. An FEV1…
15 Sep 2014 September 15, 2014 by Richard Johnston • Leave a comment
Assessing MVV results
The Maximum Voluntary Ventilation (MVV) test was initially described in 1933. It was the first pulmonary function test that involved inspiratory and expiratory air flow in a significant way and…
The Maximum Voluntary Ventilation (MVV) test was initially described in 1933. It was the first pulmonary function test that involved…
8 Sep 2014 September 8, 2014 by Richard Johnston • Leave a comment
It isn’t a Raw without a TGV
One of the key reasons to perform spirometry is to measure expiratory flow rates. The flow rate of air through any system is primarily a function of driving pressure and…
One of the key reasons to perform spirometry is to measure expiratory flow rates. The flow rate of air through…
23 Aug 2014 August 23, 2014 by Richard Johnston • Leave a comment
Looking for help with an orphaned system
I was contacted recently by a reader who is trying to resurrect an older test system. It is a Spirotech S600, manufactured by Graseby-Andersen and outfitted for spirometry, helium dilution lung…
I was contacted recently by a reader who is trying to resurrect an older test system. It is a Spirotech…
21 Aug 2014 August 21, 2014 by Richard Johnston • Leave a comment
Assessing FEV1 trends, re-visited
There are a couple of different ways to assess changes in FEV1 from one patient visit to another. For several decades my lab has used a change of >=10% and…
There are a couple of different ways to assess changes in FEV1 from one patient visit to another. For several…
19 Aug 2014 August 19, 2014 by Richard Johnston • Leave a comment
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