Feasibility of performing pulmonary function testing in cohort studies

Background: Infant lung function (IPFT) is used to monitor early lung disease. Techniques include raised-volume rapid thoracoabdominal compression (RVRTC), body plethysmography (pleth), & multiple breath washout (MBW). Little data is available on the relative feasibility of these tests. Objectives: To evaluate and compare the feasibility of different IPFTs, both at a single test occasion and longitudinally. Methods: Subjects recruited into a birth cohort study (CHILD), were invited to an early (3-9 months), mid (9-18 months) & late infancy (18-24 months) test. Most declined the early & attended a mid or late infancy visit (Table 1). MBW (by SF 6 , mass spectrometry Innovision ApS, Denmark) was performed, then pleth & RVRTC (nSpire Infant Pulmonary Lab, Longmont, USA). All tests were performed to ATS/ERS standards, with ≥2 successful trials per test. Results: 768 families were approached, 500 were interested & 231 attended at least one IPFT visit with 191 attending a follow-up. Longitudinal (≥ 2 visits) acceptable data was attained for MBW in 120 subjects, pleth in 95 and RVRTC in 63. Results for achieving acceptable data at each test occasion are described in Table 1. Conclusion: Obtaining IPFT data is challenging in cohort studies. Success in obtaining longitudinal data is best achieved using MBW methodology.