Validation and Benchmarking of a Frugal Spirometer in a Ghanaian Patient Cohort

Validation and Benchmarking of a Frugal Spirometer in a Ghanaian Patient Cohort

Biomedical engineering; Respiratory medicine; Global health

Marble Wang

Davide Piaggio (supervisor); Muhammad Farooq Shaikh (supervisor); Charles Hayfron-Benjamin (data collection)

Low-cost spirometers could improve access to lung function testing in settings with limited resources. This study compared the Frugal spirometer with Vitalograph using existing data from patients with asthma in Ghana. Records from 38 patients were reviewed, and 21 had complete, same-day measurements before bronchodilator medication, with Frugal readings passing the recorded software checks. We compared forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) using Bland–Altman analysis, intraclass correlation coefficients (ICCs) and paired t-tests with Benjamini–Hochberg adjustment. Repeatability was assessed in 15 patients using the coefficient of variation, which expresses variation in repeated readings relative to their mean. FEV1 and PEF showed encouraging agreement, with ICCs of 0.858 and 0.757, respectively. Neither showed a statistically significant mean difference after adjustment (p = 0.271 and p = 0.298). Frugal FVC averaged 0.393 L higher than Vitalograph (adjusted p = 0.014), with 95% limits of agreement from −0.714 to +1.499 L. On average, repeated FVC and FEV1 readings were more consistent with Vitalograph. Differences in the number of repeats and available information on test quality limited this comparison. Vitalograph PEF repeatability data were unavailable. These findings support further development of the Frugal spirometer, with encouraging results for FEV1 and PEF. FVC agreement and repeatability remain priorities for improvement. Non-significant p-values do not establish equivalence, and further validation is needed before the devices can be considered interchangeable.

spirometry, frugal spirometer, low-cost medical devices, asthma, Ghana, lung function, device validation, measurement agreement, repeatability