Staging of bronchiolitis obliterans syndrome using home spirometry.

OBJECTIVES: To compare the detection of bronchiolitis obliterans syndrome (BOS) in lung transplant recipients by clinic pulmonary function laboratory measurement and home spirometry. DESIGN: The subjects served as their own control group. SETTING: A university-based thoracic transplant center. SUBJECTS: Forty-five lung transplant recipients (26 women and 19 men; average +/- SD age, 47.7+/-11.4 years old at the time of transplantation). Lung function declined to at least BOS stage 1 in 17 of the 45 subjects. MEASUREMENTS: All subjects were participants in a home monitoring program utilizing home spirometry measurements. Clinic spirometry and home spirometry measurements were collected concurrently. The determinations of BOS staging were based on home and clinic FEV1 values using retrospective analysis and development of the home-based BOS staging algorithm. RESULTS: BOS stage 1 was detected an average of 341 to 276 days earlier with home spirometry than with clinic pulmonary function testing in the 17 subjects who had a pulmonary decline to BOS stage 1, depending on the persistence of the decline (1 day or 3 days, respectively). The difference in BOS detection time was statistically significant for both persistence requirements (p < 0.001). CONCLUSIONS: Home spirometry detects pulmonary decline earlier than clinic spirometry; home spirometry can be a reliable and safe alternative to frequent pulmonary function testing in lung recipients.

Determination of reliability and validity in home monitoring data of pulmonary function tests following lung transplantation.

Electronic spirometry units were used to monitor lung transplantation recipients upon their return home. The data from 77 participants were used to develop methods to verify that the pulmonary function measurements, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), were reliable and valid. The standard deviation was calculated for the best daily effort on consecutive days of home spirometry. An acceptable upper limit for the standard deviation, as the measure of day-to-day reliability, was 0.20 for FVC and 0.15 for FEV1. Validity was determined by examining the mean difference (bias) between the spirometry done in the pulmonary function laboratory and the home monitoring results. The clinic values were slightly higher, with an average difference of 0.15 for FVC and 0.12 for FEV1. Therefore, the home spirometry measurements have a high degree of reliability and validity and can now be used for early detection of serious complications.