Validation of the Nissei DS-400 in a low-resource setting.

OBJECTIVE: Hypertension affects approximately one billion individuals worldwide. The effective management of hypertension requires accurate measurement and monitoring of blood pressure. We evaluated the accuracy of a low cost self-measurement oscillometric device, with features suitable for use in a low-resource setting, in an adult population in the developing world according to the International Protocol of the European Society of Hypertension. METHODS: Trained observers using a double-headed stethoscope took nine sequential same arm measurements from 33 participants, alternating between mercury sphygmomanometry and the test device. Anyone with an arrhythmia or unclear Korotkoff sounds was excluded. Data were analyzed according to the protocol guidelines. RESULTS: The device passed all the criteria of the International Protocol with 78/95/99 and 80/95/99 of systolic and diastolic differences, respectively, within 5/10/15 mmHg of the mercury standard. It also achieved the Association for the Advancement of Medical Instrumentation criteria with a mean difference (standard deviation) of 0.8 (4.4) mmHg and -0.9 (4.5) mmHg for systolic blood pressure and diastolic blood pressure, respectively. CONCLUSION: The Nissei DS-400 can be recommended for use in the adult population, particularly in the developing world. Its impressive performance may be related to theoretical factors within the patient population and environment (e.g. temperature, humidity and altitude) that could influence the device's performance.

Development of an accurate oscillometric blood pressure device for low resource settings.

OBJECTIVE: To assess and develop an accurate blood pressure measurement device for use in low resource settings and by untrained staff, according to the World Health Organisation guidelines. METHODS: Ninety-nine adults were recruited to validate the device according to the International Protocol of the European Society of Hypertension. All participants provided written informed consent. Patients with an arrhythmia or unclear Korotkoff sounds were excluded. Nine sequential same-arm measurements were taken from each participant alternating between the test device and mercury sphygmomanometry. Differences between the test device and observers were evaluated according to the criteria of the International Protocol and the Association for the Advancement of Medical Instrumentation. RESULTS: The device failed the first assessment of the oscillometric function and required modification to both the deflation rate and the algorithm to fulfil the International Protocol criteria. It then achieved an acceptable mean difference of -0.7 (4.7) mmHg for systolic and -2.0 (4.6) mmHg for diastolic pressure (oscillometric function) and -1.9 (3.8) mmHg and -0.9 (3.3) mmHg for systolic and diastolic pressures, respectively (auscultatory function). CONCLUSION: The Microlife 3AS1-2 is a semi-automated upper arm device with features consistent with low resource requirements. We successfully developed this device for accurate blood pressure measurement in adults according to the International Protocol, through adjustment of the deflation rate and algorithm. The accuracy and user-friendly design of this low-cost device makes it a highly valuable monitor in clinical practice, particularly in low resource settings and for use by untrained staff.

Low-cost oscillometric non-invasive blood pressure monitors: device repeatability and device differences.

Automated non-invasive blood pressure measuring devices based on the oscillometric technique are used widely for self-measurement and are often used in clinics in place of the manual, auscultatory method. Oscillometry was originally developed for monitoring purposes and there are questions over its suitability for making diagnostic measurements. This study measured the differences between automated devices, in the absence of physiological variability. We studied 19 low-cost, automated, non-invasive blood pressure devices, using a repeatable artificial arm simulator, and measured the within-device repeatability and between-device differences. We found that the devices were repeatable (mean within-device difference 1 mmHg), but between-device differences were 4.4 mmHg (systolic pressure) and 3.6 mmHg (diastolic pressure), for normal and high-normal blood pressures. Individual devices are sufficiently repeatable for clinical trend use, but differences between devices are sufficiently large that they may be misinterpreted as clinically significant.

Validación del aparato oscilométrico Angelini Línea F1 para la medida clínica y la automedida de presión arterial / Validation of the Angelini Line F oscillometric device for clinical and self-measurement of blood pressure

Fundamento. La utilización creciente de aparatos automáticos y semiautomáticos para la medida de la presión arterial (PA) hace necesario que sean sometidos a procesos de validación a partir de unos criterios estandarizados. El objetivo del presente estudio ha sido el de evaluar la fiabilidad del aparato oscilométrico de medida de presión arterial en el brazo Angelini Línea F tomando como base los criterios propuestos por el Grupo de Trabajo sobre Monitorización de la Presión Arterial de la Sociedad Europea de Hipertensión. Métodos. Se han estudiado 33 individuos con rangos de PA inferiores a 130/60 mmHg (11 sujetos) entre 130160/80-100 mmHg (11 sujetos) y superiores a 160/100 mmHg (11 sujetos). En cada individuo se han realizado tres pares de medidas de presión con esfigmomanómetro de mercurio y con el aparato oscilométrico a validar, obteniéndose un total de 99 comparaciones. Resultados. De las 99 comparaciones, 47 para la PA sistólica (PAS) y 70 para la PA diastólica (PAD) presentaron diferencias 5 mmHg, 83 para la PAS y 89 para la PAD diferencias 10 mmHg y 91 para PAS y PAD diferencias 15 mmHg, cumpliendo los requisitos establecidos por la Sociedad Europea de Hipertensión. Las diferencias medias entre ambos procedimientos fueron de 2,8 ñ 8,45 mmHg para la PAS y de 1,2 ñ 6,55 mmHg para la PAD. Los coeficientes de correlación intraclase fueron de 0,969 para la PAS y de 0,925 para la PAD. Conclusiones. El aparato oscilométrico de medida de PA en el brazo Angelini Línea F cumple los requisitos de la Sociedad Europea de Hipertensión y puede considerarse válido para la medida clínica y la automedida de la PA. (AU)