ABSTRACT
BACKGROUND: Self-measurement of blood pressure (BP) has been increasingly encouraged as a supplement to measurements in the clinic. OBJECTIVE: The main objective of this study is to clinically evaluate a new device for self-measurement of BP according to the International Protocol of the European Society of Hypertension (2002). METHODS: Measurements of systolic and diastolic BP in 33 volunteers (15 for phase 1 and a further 18 for phase 2 providing 99 measurements) were obtained using the mercury sphygmomanometer (HgS; Baumanometer) and the Braun BP VitalScan Plus 1650 device. Nine sequential same-arm measurements between the test device and the standard HgS were carried out according to the International Protocol of the European Society of Hypertension in two phases (phase 1, phase 2.1 and phase 2.2). RESULTS: The device passed phase 1 as 30 systolic and 33 diastolic readings fell within 5 mmHg exceeding the 25 required. In addition, the equipment also passed phase 2.1 as 74 systolic and 77 diastolic readings fell within 5 mmHg exceeding the 65 required for being approved. Finally, it also passed the phase 2.2 as 25 volunteers for systolic and 28 for diastolic had at least 2/3 of their comparisons falling within 5 mmHg (exceeding the 22 required) and only two of the 33 volunteers had their three comparisons over 5 mmHg apart (at the most three are required). The difference-against-mean plots showed that the disagreement between the HgS and the device was -2.57+/-4.36 mmHg for systolic BP and +0.83+/-4.97 mmHg for diastolic BP, respectively. CONCLUSION: The equipment passed the different phases satisfactorily and the study suggests that it can be used for self-BP monitoring. The device, however, needs to be used with care by the patients following the instructions, because even when it may be accurate in a laboratory setting, there is potential for them to be used inaccurately in the home setting.
Subject(s)
Blood Pressure Determination/instrumentation , Oscillometry/instrumentation , Self Care/instrumentation , Aged , Female , Humans , Male , Middle Aged , Reproducibility of ResultsABSTRACT
BACKGROUND: The Sixth Report of the Joint National Committee states that the 'measurement of blood pressure outside the clinician's office may provide valuable information for the initial evaluation of patients with hypertension and for monitoring the response to treatment'. Prior to their marketing, however, blood pressure measuring devices should be independently validated for safety and accuracy using standard guidelines. OBJECTIVE: The main objective of the present study was the clinical evaluation of the Braun Precision Sensor 2550 upgrade (Braun BP 2550 (UG)) according to the International Protocol of the European Society of Hypertension (ESH). METHODS: Measurements of systolic and diastolic blood pressure in 33 subjects were obtained using the mercury sphygmomanometer (Baumanometer) and the device. The sizes of the cuffs used for different arm circumferences were 12 x 23 cm, 15 x 33 cm and 18 x 36 cm for the thin adult, adult and overweight adult, respectively. The adult size was mostly used. If the cuff of the sphygmomanometer did not fall between the two range lines, a larger or smaller cuff was required. The reproducibility of self-blood pressure measurement was compared in 33 subjects (99 measurements). Nine sequential same-arm measurements comparing the test device and the standard mercury sphygmomanometer were carried out according to the International Protocol of the ESH in three steps (phases 1, 2.1 and 2.2). RESULTS: The device passed phases 1 and 2.1 as 75 systolic and 78 diastolic readings fell within 5 mmHg, exceeding the total of 65 required for approval. It also passed phase 2.2 as 30 subjects for systolic and 29 for diastolic had at least two out of three comparisons within 5 mmHg, exceeding the 22 subjects required. The difference-against-mean plots showed that the device-sphygmomanometer disagreement was -1.58+/-4.84 for systolic pressure (the Braun being lower) and +2.23+/-3.84 for diastolic pressure (the Braun being higher), respectively. CONCLUSIONS: The equipment passed both phases of the International Protocol (subject measurements and subject accuracy). The difference of 0-5 mmHg between the sphygmomanometer and the device represents 'measurements considered to be very accurate and with no error of clinical relevance'. It can therefore be used at home as an adjunct to physicians' effort to control blood pressure in their hypertensive patients.
