Improving the diagnosis of pediatric pneumonia at village level: Testing the accuracy of smart phone applications measuring respiratory rate and O ₂ saturation

Background: Pneumonia is the commonest killer of children under 5 yrs; most deaths occur in the poorest regions. To help improve diagnosis in low-resource areas, we developed iPod/cell phone applications able to measure respiratory rate (RR) and saturation (SpO 2 ). RR is measured using RRate® software (1) which calculates RR from 5 taps of the touch screen corresponding to 5 breaths. SpO 2 is measured using an MS-2040 circuit board-in-cable attached to the iPod port. For the study, applications were run on an iPod Touch 4. We tested their accuracy against accepted standards. Methods: Two blinded observers, in each of three Indian hospitals, made paired observations on 344 children fulfilling WHO criteria for pneumonia. Observer 1 measured RR by 1 minute auscultation (RR.ausc), plus SpO 2 using Masimo Rad7 (SpO 2 .mas). Observer 2 measured RR and SpO 2 by iPod application (RR.tap and SpO 2 .ipod). Paired results compared by Bland-Altman technique. Results : There were no significant differences between RR.ausc and RR.tap or SpO 2 .mas and SpO 2 .ipod, either within or between institutions (table 1) Table 1 RR.ausc vs. RR.tap bias SpO2.mas vs. SpO2.ipod bias Bangalore 1 -1.3 +/- 6.4 bpm 0.6 +/- 3.0 %sat Chennai 1.3 +/- 4.6 bpm 0.3 +/- 1.1 %sat Bangalore 2 0.0 +/- 2.7 bpm 0.1 +/- 1.1 %sat Pooled data -0.4 +/- 5.2 bpm 0.4 +/- 2.4 %sat Conclusions: SpO 2 and RR can be measured accurately and reproducibly using cell phone technology that is easy to use and teach. This has the potential to improve the diagnosis and management of children with respiratory diseases in under-served areas. Reference: 1. https://itunes.apple.com/ca/app/rrate/id581390517?mt=8.