Objectives: To describe the reference range for heart rate in children aged 3 months–10 years presenting to primary care with self-limiting infections.
Design: Cross-sectional study of children presenting to primary care with suspected acute infection. Heart rate was measured using a pulse oximeter and axillary temperature using an electronic thermometer. Centile charts of heart rates expected at given temperatures for children with self-limiting infections were calculated.
Setting: Ten general practice surgeries and two out-of-hours centres in England.
Participants: 1933 children presenting with suspected acute infections were recruited from in-hours general practice surgeries (1050 or 54.3%) or out-of-hours centres (883 or 45.7%). After excluding children who subsequently attended hospital and those without a final diagnosis of acute infection, 1589 children were used to create the centile charts of whom (859 or 54.1%) had upper respiratory tract infections and (215 or 13.5%) non-specific viral illness.
Main outcome measures: Median, 75th, 90th and 97th centiles of heart rate at each temperature level.
Results: Heart rate increased by 9.9–14.1 bpm with each 1°C increment in temperature. The 50th, 75th, 90th and 97th centiles of heart rate at each temperature level are presented graphically.
Conclusions: Age-specific centile charts of heart rates expected at different temperatures should be used by clinicians in the initial assessment of children with acute infections. The charts will identify children who have a heart rate higher than expected for a given temperature and facilitate the interpretation of changes in heart rate on reassessment. Further research on the predictive value of the centile charts is needed to optimise their diagnostic utility.
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Competing interests: None.
Funding: This study was funded by the Medical Research Council as part of a programme grant in childhood infection in primary care (G0000340) and by the Thames Valley Research and Development Consortium support for science funding. The researchers were independent from the funders of the study. The study sponsors had no role in the study design; in the collection, analysis, or interpretation of data; in the writing of the report; nor in the decision to submit the article for publication.
Contributors: MT conceived and designed the study, supervised data collection and data management, analysed and interpreted the data, and drafted the article. He is guarantor for this article. AH contributed to study design, interpretation of the data, drafting of the article and critical revisions to the article. RP supervised the analysis and interpretation of the data, and in particular undertook the creation of centile charts and provided critical revisions to the article. RM-W was involved in design of the study, analysis and interpretation of data, drafting the article and critical revisions to drafts of the article. LS was involved in coordination of data collection and data management, and interpretation of data and provided critical revisions to the article. DMcL was involved in design of the study, coordination of data collection and data management, and provided critical revisions to the article. DM was involved in study design, interpretation of data and critical revisions to drafts of the article. All the authors contributed to drafts of the article, and revised, commented on and contributed to various drafts of the paper and read and approved the final draft.
Ethics approval: Ethics approval was obtained from Oxford Research Ethics Committee C (C00.180).