Paradoxical bronchospasm, although rare, should be recognized more often in spirometry tests, said pulmonologist Malvika Kaul, MD, who discussed study findings from a population of veterans with chronic obstructive pulmonary disease (COPD) and asthma, where the possibly life-threatening condition was not picked up in lung tests.
Paradoxical bronchospasm, although rare, should be recognized more often in spirometry tests, said Malvika Kaul, MD, a pulmonologist in Chicago, Illinois, who discussed study findings presented at the CHEST Annual Meeting 2021 from a population of veterans with chronic obstructive pulmonary disease (COPD) and asthma, where the possibly life-threatening condition was not picked up in lung tests.
Why did you conduct a study of paradoxical bronchospasm in veterans with COPD and asthma, and what did you find?
So the reason I conducted this study was I actually had a patient who had this phenomenon. And that made me realize that I also did not know much about this entity and decided to look back and see in our veteran patients how many other people were recognizing it, and was it being reported. So that's how I started looking at various different spirometries and looking for this phenomenon in X number of years. What we found was that, actually no one in the spirometry reported this phenomenon when it was positive, so we reviewed about 1150 spirometries and we actually found 18 that met the criteria that we were using and that have been used in literature before. And I can talk about the criteria in a bit, but we reviewed [pulmonary function tests] from 2017 to 2020. And none of those 18 were reported, and that includes the patient I first saw, and because it was not reported, it was not even reported in patients’ charts, not in their spirometry, so no action was taken. So, what we wanted with our study was to kind of recognize that this entity exists and that it should be reported, and hence its consequences to be addressed thereafter.
What were the criteria?
It's an interesting question, because paradoxical bronchospasm is not extensively published as a regular bound for dilation in spirometry, which is very well known and very well studied. What in literature that has been used as criteria for bronchospasm is similar to bronchodilations. So, according to [American Thoracic Society] criteria, bronchodilation is a change in 12% and 200 mL of FEV1 [forced expiratory volume in 1 second] or FVC [forced vital capacity], from pre- to post bronchodilator, using about 4 puffs of albuterol. And in the studies before, what they have done for bronchoconstriction, or bronchospasm, in that sense, is just basically the flip of that, that is, not an increase, but a decrease of FEV1 or FVC after that bronchodilator, 12% and 200 mL. And that's kind of what we chose as our criteria too. Because it's a rare entity, there's not any big studies or big literature out there—is this the criteria that should be used vs not used—just because bronchodilation is used more frequently. That's how all the studies before, including big cohorts, like COPD gene study, have used this criteria, so that's kind of what we used as well.