The association between temperature, heart rate, and respiratory rate in children aged under 16 years attending urgent and emergency care settings

Background and importance Body temperature is considered an independent determinant of respiratory rate and heart rate; however, there is limited scientific evidence regarding the association. This study aimed to assess the association between temperature, and heart rate and respiratory rate in children. Objective The objective of this study was to validate earlier findings that body temperature causes an increase of approximately 10 bpm rise in heart rate per 1 °C rise in temperature, in children aged under 16 years old. Design A prospective study using anonymised prospectively collected patient data of 188 635 attendances, retrospectively extracted from electronic patient records. Settings and participants Four Emergency or Urgent Care Departments in the North West of England. Participants were children and young people aged 0-16 years old who attended one of the four sites over a period of 3 years. Outcome measures and analysis Multiple linear regression models, adjusted for prespecified confounders (including oxygen saturation, heart rate, respiratory rate, site of attendance, age), were used to examine the influence of various variables on heart rate and respiratory rate. Main results Among the 235 909 patient visits (median age 5) included, the mean temperature was 37.0 (SD, 0.8). Mean heart rate and respiratory rate were 115.6 (SD, 29.0) and 26.9 (SD, 8.3), respectively. For every 1 °C increase in temperature, heart rate will on average be 12.3 bpm higher (95% CI, 12.2-12.4), after accounting for oxygen saturation, location of attendance, and age. For every 1 °C increase in temperature, there is on average a 0.3% decrease (95% CI, 0.2-0.4%) in respiratory rate. Conclusion In this study on children attending urgent and emergency care settings, there was an independent association between temperature and heart rate but not between temperature and respiratory rate.