The relationship between body temperature, heart rate and respiratory rate in children

Aim: To describe and quantify the effect that increasing body temperature has on heart rate and respiratory rate in children attending a paediatric emergency department (ED). Methods: Data on pulse, temperature, respiratory rate and age were collected from attendances to two children's ED in the UK between 2003 and 2006. Triage observations as documented at the time were collated and analysed. Results: Data on a total of 63 857 attendances were examined, 31 851 with complete data. Data on children not sent home from the ED were removed, to exclude any patient with haemodynamic shock. The remaining dataset of 21 033 patients with data for heart rate and 14 487 with data for respiratory rate were studied. The state of agitation of the patient was not considered in this study. Conclusion: Body temperature is an independent determinant of heart rate, causing an increase of approximately 10 beats per minute per degree centigrade. Body temperature is also an independent determinant of respiratory rate. This quantification may help in the assessment of the hot and unwell child, to determine whether any tachycardia or tachypnoea is caused solely by fever, or whether there may be an element of concurrent shock.