EPS1.06 A retrospective audit of home-based spirometry quality in a large UK adult cystic fibrosis centre

Objectives: Spirometry measurement is the gold standard for assessing disease severity in cystic fibrosis (CF). Poor-quality spirometry tests can result in inaccurate measurement of FEV1 and FVC. Manchester Adult CF Centre has transformed from hospital to home-based spirometry testing during COVID-19. Unlike hospital-based spirometry, home-based spirometry relies entirely on the subject to obtain good quality spirometry. Therefore, we sought to ascertain the quality of home-based spirometry and the test errors in our patients. Methods: A convenience sample of adults with CF attending Manchester Adult CF Centre were provided with a NuvoAir home-based spirometer to perform routine lung function between March–October 2020. NuvoAir respiratory platform consists of a mobile phone application, Bluetooth spirometer and an online results portal. The spirometer also provides feedback to patients’ spirometry quality. Initial patient set-up was performed in-hospital or virtually with a member of the CF clinical team. All patient sessions were included irrespective of quality of spirometry test session. Acceptability and repeatability criteria were applied as per NuvoAir software in line with ATS/ERS guidelines, along with assigning a quality grading A–Faccording to ATS/ERS standardised pulmonary function report criteria at time of testing. Results: 66 CF patients (32 female) mean age 31.3 (18–55) performed 343 spirometry sessions totaling 1,041 individual spirometry tests with a NuvoAir device were graded as follows: Grade A = 30.3%, Grade B = 36.2%, Grade C = 3.5%, Grade D = 2.6%, Grade E = 16.6%, Grade F = 10.8%. Further analysis of all 1,041 tests for common errors indicated BX – Back extrapolation 2%, TP- Time to Peak (slow start) 14.6%, CO – Cough 1.4%, ET – Early termination 0.5%, CE – Cessation or glottic closure 12.9%. Overall, general tests A–C considered usable was 70%. Conclusion: The results show good-quality standards can be achieved through home-based spirometry.