Clinical evaluation of a self blood pressure monitor according to the First International Consensus Conference on Self Blood Pressure Measurement.

Abstract

The Calor TensioSense Bras automatic blood pressure monitor has obtained European Union certification, but the clinical validity of this new oscillometric device when handled by lay subjects has yet to be evaluated. The design employed prospective and blinded blood pressure measurements and a validation procedure according to the criteria set out by the First International Consensus Conference on Self Blood Pressure Measurement (1999). Thirty-three subjects were recruited, 11 in each of three strata of systolic blood pressure (<130, 130-160 and >160 mmHg). Blood pressure was measured sequentially seven times, alternating observer and lay measurements. Two certified observers used two mercury columns and a double stethoscope; the subjects used the automatic device. All blood pressure readings and recordings were blinded. Adequate cuff sizes were used, and the subjects' position was standardized. Discrepancy analysis between manual and automatic measurements was carried out using VAPA software. Dispersion of the discrepancies between manual and automatic measurements showed no specific trend. Out of the 99 systolic blood pressure measurements, 53, 76 and 89 discrepancies were less than 5, 10 and 15 mmHg, respectively. Of the 99 diastolic blood pressure measurements, 62, 86 and 97 discrepancies were less than 5, 10 and 15 mmHg, respectively. The mean inter-observer discrepancy was 1 mmHg for both systolic and diastolic blood pressure comparisons. This evaluation showed that this device complies with the international validation protocol requirements. Thus, the device can, providing adequate instruction is given in the clinic, be recommended for self-measurement by patients at home, as well as for clinical or epidemiological research.