Background: It is widely accepted that fever is associated with tachycardia. There is a consistent linear relationship between pulse rate and body temperature and is more seen in infants between 2 and 12 months of age. It is important to determine in children with fever and tachycardia whether the severity of the tachycardia is proportional to the temperature or whether another cause of fever. The aim of this study was to the relationship between pharmacological temperature reduction, heart rate and activity level in febrile children.
Methods: Prospective study.Children presenting with fever to the pediatric ED of the Dana-Dwek Children`s Hospital and Shaare Zedek. Temperature, heart rate and the child`s state will be documented at initial assessment and 1 hour following antipyretic administration.
Results: We found that the known relation of increase of 9.6 bpm per 1Oc upon temperature rise is not maintained in temperature reduction. The average heart rate decrease was of 21.1 bpm with a p_value = 0.002673, 95% CI (14.05 – 28.15). There is also promising evidence that the level of reduction differs between children with suspected having a serious bacterial infection (SBI) vs. those who are not.
Conclusion: Our finding that the reduction of fever does not maintain the same relation as the rise of fever, can have clinical implementation when assessing an infant. A possible explanation can be related with the antipyretic drug mechanism of action. Validation of this finding could be a useful clinical feature to integrate with the assessment of an infant with fever
