Background: Ambulatory blood pressure (ABP) monitoring is used increasingly to evaluate the blood pressure of children and adolescents. Reference values based on a sufficiently high number of healthy children are necessary to estimate the limits of the 'normal' range.
Objective: To begin to define the normal range of values for pediatric ABP.
Design: In this multicenter trial, we pooled ABP records of 1141 healthy children and adolescents with body heights between 115 and 185 cm. The study was carried out at seven centers, according to a common procedure. Only oscillometric devices (SpaceLab 90207 and Meditech) were included in the evaluation.
Results: The 50th percentile for 24h systolic ABP increased moderately with height, from 103 mmHg to 113 mmHg in girls and from 105 mmHg to 120 mmHg in boys. The 50th percentile for diastolic 24h means was 66+/-1 mmHg, irrespective of height or sex. Diastolic daytime means were 73+/-1 mmHg, which is remarkably high compared with reference values for casual blood pressure. The mean nocturnal systolic and diastolic ABP values (0000-0600 h) were 13+/-6% and 23+/-9% less than the daytime means (0800-2000h), respectively.
Discussion: This multicenter study is, to date, the largest descriptive estimation of the normal range of values for pediatric ABP monitoring. Further investigation is needed, to evaluate the influences of genetic and environmental background, and that of the monitoring device, on pediatric ABP measurements. The optimal range for ABP in children as defined by cardiovascular prognosis or end-organ damage remains to be established.