Evaluation of the Dinamap 8100 and Omron M1 blood pressure monitors for use in children

The aim of this study was to evaluate the Dinamap 8100 and the Omron M1 (the test devices) against standard criteria for use in children in a fieldwork setting. Device calibration and validation were carried out in accordance with the British Hypertension Society protocol for special groups such as children. A total of 102 children, recruited from infant and junior schools in Southampton, had six sequential measurements made of their blood pressure-four measurements with a mercury sphygmomanometer and two with one of two test devices, 55 children with the Dinamap 8100 and 47 with the Omron M1. Systolic and diastolic readings with the Dinamap 8100 were on average 11 mmHg higher (95% confidence interval [CI] +9, +12 mmHg) and 3 mmHg lower (95% CI -5, -1 mmHg), respectively, than measurements with the mercury sphygmomanometer, overestimating systolic pressures and underestimating diastolic pressures across the whole range observed. The Omron M1 gave readings lower by 1 mmHg on average for systolic pressures and 2 mmHg for diastolic pressures compared with the sphygmomanometer (95% CIs -4, +1 mmHg and -5, +1 mmHg respectively), specifically overestimating higher pressures and underestimating lower pressures. According to the criteria of the British Hypertension Society, neither the Dinamap 8100 nor the Omron M1 can be recommended for use in children in clinical situations in which accuracy of the absolute measurement is required. In epidemiological surveys, in which differences in blood pressure between groups of people are more important than absolute levels, it may be more appropriate to use these devices. Of the two, its more consistent performance supports the Dinamap 8100 as the instrument of choice in such studies of children.