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Rebuttal From Drs Hansen and PorszaszRebuttal From Drs Hansen and Porszasz FREE TO VIEW

James E. Hansen, MD, FCCP; Janos Porszasz, MD, PhD
Author and Funding Information

From the David Geffen School of Medicine at UCLA and Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center.

CORRESPONDENCE TO: James E. Hansen, MD, FCCP, Department of Medicine, Harbor-UCLA Medical Center, Box 405, Torrance, CA 90502; e-mail: jhansen @labiomed.org


FINANCIAL/NONFINANCIAL DISCLOSURES: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2014;146(3):542-544. doi:10.1378/chest.14-0618
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Published online

We welcome the opportunity to respond to Drs Pellegrino and Brusasco.1 We are concerned primarily with their statement that “the acute response to bronchodilators is relatively easy to interpret when changes in FEV1 or FVC exceed the thresholds of their natural intraday variability (ie, 12% of baseline and 200 mL), thus, unequivocally indicating bronchodilation.”1

To test this statement with real data,2 we identified the most severe 44 of 316 patients with their initial highest FEV1 < 1.00 L (Table 1). We sorted them into three categories depending on their response to nebulized albuterol. Importantly, both the preaerolized and postaerosolized albuterol variability of these patients’ FEV1 values were low (the postdrug variabilities are not presented). Considering the highest and lowest predrug FEV1 values of each patient with an FEV1 < 1.00 L, the range of predrug highest and lowest individual values was between 10 and 200 mL with a mean ± SD of 56 ± 40 mL. All these results were from a retrospective analysis of patients routinely studied in a clinical laboratory; thus, we believe that this population is highly relevant to the topic.

Table Graphic Jump Location
TABLE 1  ] Baseline Values in 44 of 316 Patients With Highest Baseline FEV1 < 1.00 L

Data are presented as mean ± SD (range) unless otherwise indicated. ATS/ERS = American Thoracic Society/European Respiratory Society; Dlco = diffusing capacity of lung for carbon monoxide; RV = residual volume; SS = statistically significant (by both rank order [P = .05] and one-tailed t tests [P < .05]); TLC = total lung capacity.

Of these 44 patients, only five met American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines for positive findings; 23 others had statistically significant (SS) individual increases in FEV1 by one- or two-tailed t tests and rank order tests but did not meet ATS/ERS guideline criteria for an abnormal response; and another 16 did not have SS increases or meet ATS/ERS guideline criteria. (Note that P = .0212 with a one-tailed test yields P = .0424 with a two-tailed test and is still significant at the 5% level.) Thus, 23 of these 44 patients with the most severe obstruction who had individual SS responses would not have been categorized as responders using current ATS/ERS guidelines. Thus, interpreting responsiveness based on these guidelines seems to be seriously flawed; moreover, the guidelines act against patients with the lowest FEV1 values, those likely to be most in need of bronchodilation.

Currently, with most spirometric equipment, satisfactory quality control of volumes tolerates a 3% positive or negative error during calibration, a factor that increases measurement variability. Thus, higher variability is likely when patients are studied months apart by different technicians, with different equipment, or over full days; lower variability will be found with repetitive testing performed over 1 h or so with the same equipment, patient, and technician, as is typical with responsiveness testing in the laboratory.

One might ask how these guideline criteria are developed. Factors include using older equipment and group values, which broaden normal variability; insisting on both volume and percent change; and adding FVC values.

It deserves mentioning again that the ATS/ERS guidelines are derived from very diverse populations. Translating those population-based findings and requiring both volume and percent changes to an individual patient requires an unnecessary leap of faith because each individual provides sufficient data to assess the statistical significance of his or her responsiveness. That and the magnitude of responsiveness should assist the clinician in interpreting the laboratory findings for that individual.

References

Pellegrino R, Brusasco V. Point: is an increase in FEV1and/or FVC ≥12% of control and ≥200 mL the best way to assess positive bronchodilator response? Yes. Chest. 2014;146(3):536-537.
 
Hansen JE, Sun XG, Adame D, Wasserman K. Argument for changing criteria for bronchodilator responsiveness. Respir Med. 2008;102(12):1777-1783. [CrossRef] [PubMed]
 

Figures

Tables

Table Graphic Jump Location
TABLE 1  ] Baseline Values in 44 of 316 Patients With Highest Baseline FEV1 < 1.00 L

Data are presented as mean ± SD (range) unless otherwise indicated. ATS/ERS = American Thoracic Society/European Respiratory Society; Dlco = diffusing capacity of lung for carbon monoxide; RV = residual volume; SS = statistically significant (by both rank order [P = .05] and one-tailed t tests [P < .05]); TLC = total lung capacity.

References

Pellegrino R, Brusasco V. Point: is an increase in FEV1and/or FVC ≥12% of control and ≥200 mL the best way to assess positive bronchodilator response? Yes. Chest. 2014;146(3):536-537.
 
Hansen JE, Sun XG, Adame D, Wasserman K. Argument for changing criteria for bronchodilator responsiveness. Respir Med. 2008;102(12):1777-1783. [CrossRef] [PubMed]
 
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