Effect of attaching ChARM automated respiratory rate counter on actual respiratory rate in children

Accurate respiratory rate (RR) measurement is essential for diagnosing and classifying pneumonia in children. The Children's Automated Respiration Monitor (ChARM) can measure RR, but placing the device on the chest may influence a child's breathing. This study evaluated whether ChARM affects RR measurement and identification of fast breathing. We conducted a cross-sectional study in multiple health facilities in Bangladesh (2021-2022). Children aged 0-59 months presenting with suspected pneumonia were enrolled. RR was first measured manually by a physician or a health worker and then using ChARM, while chest movements during both measurements were video recorded. A six-member video expert panel (VEP) reviewed all recordings and derived manual RR. Differences in RR values and fast breathing classifications between the two measurement methods were examined. Of 339 enrolled children, both manual and ChARM measurements were obtained for 294; the remainder could not be assessed because of crying or movement. The child's condition remained same during both measurements in 256 cases. After excluding uninterpretable videos and readings without consensus, VEP-determined RR was available for 217 children. The mean difference in RR between the two measurements was 0.5 breaths per minute (standard error 0.4). RR classification (normal vs. fast breathing) changed in 21 children (9.7%), with moderate agreement between measurements (kappa = 0.749). ChARM did not significantly alter mean RR, though classification changed for a small proportion of children. Because exclusions and non-interpretable videos may have introduced bias, additional studies are required to more definitely evaluate whether device attachment influences RR or fast-breathing classification. Supplementary Information: The online version contains supplementary material available at 10.1007/s44337-026-00595-8.