Performance and usability of a new mobile application for measuring respiratory rate in young children with acute lower respiratory infections

Objectives: Respiratory rate (RR) measurement is critical to diagnosing pneumonia in resource-constrained settings, but accurate RR measurement is challenging. The acute lower respiratory illness treatment and evaluation (ALRITE) mobile phone application (app), designed to help healthcare workers (HCWs) manage pediatric respiratory illnesses, includes a semiautomated RR counter. This study aimed to evaluate the accuracy and usability of the ALRITE RR counter and a commercially available RR counter app, RRate, with a reference standard. Methods: This was a cross-sectional observational study of HCWs. Participants used both apps to measure the RR of pediatric patients from standardized videos. The reference standard was determined by consensus of a manual 1-min count by two providers. We assessed agreement using Spearman's rank correlation coefficient and constructed Bland–Altman plots to determine bias and limits of agreement. Participants completed a usability survey. Results: Thirty-nine HCWs participated. The agreement between the apps and reference standard (Spearman's coefficient) was 0.83 (95% confidence interval [CI]: 0.78–0.87) for ALRITE and 0.62 (95% CI: 0.52–0.70) for RRate. ALRITE had a bias of −2 breaths/min (lower limit of agreement [LoA] −16 to +12) and RRate had a bias of −0.4 breaths/min (LoA −24 to +23) compared to the reference standard. Both apps had a poorer agreement at higher RRs. Based on usability survey responses, 95% found ALRITE easy to use. Conclusions: The ALRITE RR counter has acceptable accuracy for counting RR in infants with respiratory distress, appears to be more accurate than a commercially available option, and was user-friendly. The ALRITE RR counter is a promising tool for meriting evaluation in real-world settings.