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.