Spirometry Quality in Adults With Very Severe Lung Function Impairment

BACKGROUND: Some technologists worry that patients with very severe lung disease are unable to complete several spirometry maneuvers, which require considerable effort. METHODS: We retrospectively selected all spirometry tests with an FEV1 < 35% predicted done by adult subjects sent to our pulmonary function laboratory during a 3-y period. We determined the rates and correlates of poor quality test sessions. RESULTS: Approximately 90% of the tests done by the 558 subjects with very severe lung-function impairment (of > 30,000 subjects tested during the 3-y period) had adequate quality spirometry. Subjects with airway obstruction were less likely to meet FVC repeatability goals. A poor spirometry quality grade was associated with a very low FVC and a low body mass index, but not older age. CONCLUSIONS: Severe lung disease should not be used as an excuse for not meeting spirometry quality goals.