Poor inter-observer agreement in the measurement of respiratory rate in children: a prospective observational study

OBJECTIVE: To determine the inter-observer agreement of a respiratory rate (RR) count on a child when assessed by three independent observers. DESIGN: The RR of 169 children (age range: 3 days to 15 years) was measured by three independent observers over a 3-month period. The first RR was taken by different healthcare professionals (HCPs) from within the hospital using their own preferred method of measurement. A further count of RR was then taken by two observers from the research team simultaneously within 30 min of the first measurement, using the WHO-recommended method of measurement. RESULTS: 507 RR measurements were taken on 169 children. Median RR showed a 4 beats per minute (bpm) difference between the HCP (median RR 32 bpm) and the researchers (median RR 28 bpm). The 95% limits of agreement between the first measurement and second and third measurements were −10.2 to 17.7 bpm and −11.4 to 18.7 bpm, respectively. For simultaneous measurements, the 95% limits of agreement were −7.1 to 7.0 bpm. 81 children had a RR > 95th centile for their age and an even poorer level of agreement was seen in these children than in those whose RR was within normal range. In only 27 of these 81 children (33%) did all three observers agree on the presence of a raised RR. CONCLUSIONS: Inter-observer agreement for the measurement of RR in children is poor. The effect that this variation has on the clinical assessment and subsequent management of a child may be significant. These findings highlight the need for a robust review of our current measurement methods and interpretation of an important vital sign.