Comparison of the oscillometric blood pressure monitor (BIRM-100(beta)) with the auscultatory mercury sphygmomanometer

Background To compare directly the accuracy of the BPM-100(Beta) monitor (a n automated oscillometric blood pressure device) with standard auscultatory mercury sphygmomanometry. Design The BPM-100(Beta) was connected in parallel via a T-tube to a mercur y sphygmomanometer. The BPM-100(Beta) and two trained observers (blinded fr om each other and from the BPM-100(Beta)) measured the sitting blood pressu re simultaneously. Methods Means, standard deviations and ranges were calculated for all the d emographic data: age, arm size, heart rate and blood pressure. The agreemen t between the BPM-100(Beta) and the mean of two observers (the reference) w as determined and expressed as the mean SD, as well as the percentage of di fferences failing within 5, 10 and 15 mmHg. Results Of the 92 subjects recruited, 85 (92.4%) met the inclusion criteria , and 391 sets of sitting blood pressure and heart rate measurements were a vailable for analysis. The mean difference between the BPM-100(Beta) monito r and the reference was -0.62 +/- 6.96 mmHg for systolic blood pressure, -1 .48 +/- 4.80 mmHg for diastolic blood pressure and 0.14 +/- 1.86 beats/min for heart rate. The only limitation of the device was its tendency to under estimate higher systolic blood pressures. This problem has been addressed b y a minor change in the algorithm (see the companion publication, Blood Pre ss Monit 6: 161-165, 2001). Conclusion The BPM-100(Beta) is an accurate blood pressure monitor for the office setting, meeting all requirements of the Association for the Advance ment of Medical Instrumentation and achieving an 'A' grade according to the British Hypertension Society protocol. (C) 2001 Lippincott Williams & Wilk ins.