A5V4d

Clinical assessment of the child with fever
Centiles charts of pulse rate plotted against temperature in febrile children younger than 1 year were
produced. The linear regression analysis of the relation between pulse rate and temperature is shown
in Table 5.50.
Table 5.50 Linear regression analysis of the relation between pulse rate and temperature
Age (months) Adjusted R 2 Mean increase in pulse rate (bpm) per 1 o C
increase in temperature (95% CI)
0–1 0.004 2.2 (-1.3 to 5.6)
2–3 0.16 10.0 (5.1–14.8)
4–5 0.25 10.6 (6.4–14.8)
6–7 0.22 9.2 (4.9–13.4)
8–9 0.10 6.8 (1.8–11.7)
10–11 0.38 10.9 (6.9–14.9)
bpm beats per minute, CI confidence interval
This study found that for every 1°C rise in body temperature, the resting heart rate rose by 9.6 bpm.
A number of limitations were identified: baseline figures were not controlled in analysis; there was
limited reporting on exclusion criteria; and inconsistency was observed in the data from children with
very low or very high temperature.
The GRADE evidence profiles for this review question are presented in Table 5.51.
Table 5.51 GRADE profile of study quality for change in heart rate with change in body temperature
Number of studies Number of children Quality
Change in heart rate (with increasing body temperature)
1 study (Davies, 2009) 21,033 a Very low
Change in heart rate (with increasing body temperature) e
1 study (Thompson, 2009) 1,589 b Low
Change in heart rate (with increasing body temperature)
1 study (Hanna, 2004) 490 c Very low
a The data were analysed using a quantile regression and a statistical model to develop a best fit equation:
Expected parameter value = (Temperature ( o C) × a) + (Age (months) × b) + (Age 2 (months 2 ) × c) + constant
The temperature multiplier a has a mean increase of 10.52 beats per minute (bpm) through the centile, resulting in a heart rate
increase of approximately 10 bpm with each 1 o C increment in temperature.
b Children were not truly representative of a primary care population due to problems with recruiting. Recruitment was not
systematic, the proportion of children consulting out-of-hours care was high, and the researcher set the minimum recruitment
targets for each age–temperature combination.
c Mean increase in pulse rate per 1 o C increase in temperature was calculated using linear regression analysis of the relation
between pulse rate and temperature. The authors report that for every 1 o C rise in body temperature, the resting heart rate rose
by 9.6 bpm.
Heart rate alone in the clinical assessment of serious illness
Three studies were considered that examined the use of heart rate for detecting serious illness.
The study by Brent (2011) found a positive association between the risk of serious bacterial infection
and heart rates (probability [P] = 0.0005) (see Table 5.53 for GRADE profile). A correlation between
tachycardia and serious bacterial infection was also found in this dataset (odds ratio [OR] 2.90,
confidence interval [CI] 1.60 to 5.29; P = 0.0002). Table 5.52 shows diagnostic usefulness was high
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2013 Update