Chest

Chest

Volume 123, Issue 6, June 2003, Pages 1899-1907
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Clinical Investigations
Asthma
Evaluating the Use of a Portable Spirometer in a Study of Pediatric Asthmaa

https://doi.org/10.1378/chest.123.6.1899Get rights and content

Study objectives

Laboratory-based spirometry is the “gold standard” for the assessment of lung function, both in clinical and research protocols. These spirometers, however, are neither practical nor affordable for home-based monitoring or studies that collect data in multiple locations. Traditionally, peak flowmeters have been used, but they have important limitations.

Design

Based on data from a cohort of 92 children with asthma, we evaluated the agreement between a portable spirometer and a office-based spirometer, using an in-line technique to evaluate measures from the same effort. We compared a range of pulmonary function parameters collected during office-based tests, and also evaluated whether adequate adherence and data quality could be achieved in a home-based study of children with asthma.

Results

The agreement between the devices for the actual values of peak expiratory flow, FEV1, and forced expiratory flow at 25% of FVC was excellent. The portable device was programmed with customized software to grade each curve using revised American Thoracic Society acceptability and reproducibility criteria. For 74% of the curves, quality grade agreed with a grade assigned by physician review of the curve from the office-based spirometer. During 2 weeks of twice-daily monitoring at home, children completed an average of 23 of 28 possible sessions (83%). Of these, 84% had at least two acceptable and two reproducible curves. Although children ≥ 8 years old were not more adherent, they were significantly more likely to achieve acceptable and reproducible curves.

Conclusions

Portable spirometers can provide measurements that are highly comparable to those obtained from “gold standard” laboratory spirometers, and high-quality tracings can be achieved both at home and in the office setting. Visual inspection of the curves by experienced reviewers identified unacceptable curves that were not rejected by the quality control software. Portable spirometers are an important contribution to epidemiologic and clinical studies that require frequent measures of a more broad range of pulmonary function parameters than can be provided by peak flowmeters.

Section snippets

Study Population

This report includes a subset of 92 children enrolled in the Fresno Asthmatic Children’s Environment Study (FACES), a longitudinal study of the effect of air pollution and other environmental agents on the health of asthmatic children aged 6 to 11 years. The study was approved by the Committee for the Protection of Human Subjects of the University of California, Berkeley, and the Committee on Human Research at University of California at San Francisco.

The FACES design consists of longitudinal

Office-Based Spirometry

The characteristics of the first 92 children who completed the in-line testing and who completed the 2-week panel can be found in Table 2. Table 3presents the curve-by-curve evaluation from each method for determining acceptability. Among the 530 curves from 180 sessions, the overall agreement between the physician and software acceptability scores was 74%. Based on the slightly more stringent criteria (eg, mid-curve review by a physician), significantly more curves from the office-based

Discussion

The first goal of this study was to evaluate whether pulmonary function data from a portable spirometer are comparable to those obtained from an office-based spirometer. Comparability was determined in two ways. First we compared acceptability scores (yes/no) for the data from each device. In addition, we graphically compared the magnitude of a range of pulmonary function measures. Although we could not find any references of comparable in-line evaluations, we found the agreement between the

Conclusion

We conclude that this portable spirometer accurately and reliably measures pulmonary function, relative to a “gold standard” office-based device. Although there was good agreement across key lung function measures, physician review of the curves revealed some limitations in our current quality control software. We achieved a high degree of compliance during 2-week intervals, even among the youngest children who had difficulty producing reproducible tracings. The compliance was substantially

Acknowledgment

The authors thank Romain Neugebauer for statistical analysis; Paul Enright, MD, for suggesting the incentive scoring system; and the FACES staff and the FACES families, whose hard work and cooperation made this study possible.

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Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (e-mail: [email protected]).

The study was funded by the California Air Resources Board, Contract 99-322.

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Copyright © 2003 The American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.