Evaluation of the measurement of children's blood pressure in an epidemiological multicentre study

Reliability and repeatability of blood pressure (BP) measurements performed by both a local nurse and a control nurse visiting all five study areas in the Finnish Multicentre Study were analysed. As an objective control, Rose's tape recordings were played at least three times during the study period to each nurse. It was found that the nurses differed from each other with variations of 2.5 mm Hg, 54.6 mm Hg and 17.9 mm Hg in the recordings of systolic, diastolic Korotkoff's IV (KIV) phase and diastolic KV phase sounds respectively, in assessing the tape. Correlation coefficients between the systolic BP and diastolic BP measurements made by the local and control nurses in 3-year-old children varied from 0.10 to 0.72 and from -0.16 to 0.46 respectively. Correlation coefficients in 6-18-year-old subjects between systolic, diastolic KIV and diastolic KV BP measurements made by the control and local nurses varied from 0.69 to 0.81, from 0.42 to 0.63 and from 0.38 to 0.58 respectively. All of the nurses had a significant terminal digit preference and it was pronounced in two of them. Because of these findings it was concluded that comparisons of BP values in different areas should be done cautiously.