Pneumonia is one of the leading causes of death in children under-five globally. The current diagnostic criteria for pneumonia are based on increased respiratory rate (RR) or chest in-drawing in children with cough and/or difficulty breathing. Accurately counting RR is difficult for community health workers (CHWs). Current RR counting devices are frequently inadequate or unavailable. This study analysed the performance of improved RR timers for detection of pneumonia symptoms in low-resource settings.
Four RR timers were evaluated on 454 children, aged from 0 to 59 months with cough and/or difficulty breathing, over three months, by CHWs in hospital settings in Cambodia, Ethiopia, South Sudan and Uganda. The devices were the Mark Two ARI timer (MK2 ARI), counting beads with ARI timer, Rrate Android phone and the Respirometer feature phone applications. Performance was evaluated for agreement with an automated RR reference standard (Masimo Root patient monitoring and connectivity platform with ISA CO2 capnography). This study is registered with ANZCTR [ACTRN12615000348550].
While most CHWs managed to achieve a RR count with the four devices, the agreement was low for all; the mean difference of RR measurements from the reference standard for the four devices ranged from 0.5 (95% C.I. − 2.2 to 1.2) for the respirometer to 5.5 (95% C.I. 3.2 to 7.8) for Rrate. Performance was consistently lower for young infants (0 to < 2 months) than for older children (2 to ≤ 59 months). Agreement of RR classification into fast and normal breathing was moderate across all four devices, with Cohen's Kappa statistics ranging from 0.41 (SE 0.04) to 0.49 (SE 0.05).
None of the four devices evaluated performed well based on agreement with the reference standard. The ARI timer currently recommended for use by CHWs should only be replaced by more expensive, equally performing, automated RR devices when aspects such as usability and duration of the device significantly improve the patient-provider experience.
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