Annemarie de Greeff

Accuracy of inflationary versus deflationary oscillometry in pregnancy and preeclampsia: OMRON-MIT versus OMRON-M7

ObjectiveTo assess the accuracy of the OMRON-MIT (inflationary) and OMRON-M7 (deflationary) devices for measuring blood pressure in a pregnant population, including women with preeclampsia, according to the British Hypertension Society protocol. MethodsForty-five pregnant women, including 15 with preeclampsia, were recruited at a large teaching hospital. Nine sequential same arm measurements were taken from each patient alternating between the test device and mercury sphygmomanometry. Both devices were assessed in the same women. Data were analysed according to the British Hypertension Society protocol. ResultsThe OMRON-MIT achieved an A/A grade in both pregnancy and preeclampsia with an overall mean difference (SD) of −1.3 (5.6) mmHg and 0.4 (5.6) mmHg for systolic and diastolic pressures, respectively. The OMRON-M7 achieved an A/A grade in pregnancy and a B/B grade in preeclampsia with an overall mean difference (SD) of −5.3 (6.6) mmHg and −3.5 (6.9) mmHg. ConclusionBoth the OMRON-MIT and the OMRON-M7 can be recommended for use in pregnancy and preeclampsia. Inflationary oscillometry (OMRON-MIT) was more accurate in preeclampsia.

An accurate semiautomated oscillometric blood pressure device for use in pregnancy (including pre-eclampsia) in a low-income and middle-income country population: the Microlife 3AS1-2.

ObjectivesTo assess the accuracy of the Microlife 3AS1-2 blood pressure device in pregnancy and pre-eclampsia in a low-resource setting. MethodsProspective validation according to the British Hypertension Society protocol. A total of 45 pregnant women were recruited from Kimberley Hospital (South Africa), of whom 15 had pre-eclampsia. ResultsThe Microlife 3AS1-2 device achieved an overall B/A grade in pregnancy (including pre-eclampsia), passing the British Hypertension Society protocol requirements and achieving the International Organization for Standardization standard with a mean difference and SD of −3.8±7.3 and −1.5±6.2 mmHg for systolic and diastolic pressures, respectively. ConclusionThe Microlife 3AS1-2 device can be recommended for use in pregnancy, including pre-eclampsia. In addition, it fulfils the requirements stipulated by the WHO for an automated blood pressure device suitable for use in a low-resource setting. This makes it the ideal device for antenatal clinics and primary healthcare facilities in low-income and middle-income countries.

Validation and compliance of a home monitoring device in pregnancy: microlife WatchBP home.

Objective. To assess the accuracy and patient compliance in using a novel home blood pressure monitoring device in high-risk pregnancy. Methods. Device accuracy was assessed according to the British Hypertension Society protocol in 45 pregnant women, including 15 with preeclampsia. Twenty-one high-risk pregnant women used the device in addition to their antenatal care. Results. The device achieved a mean difference ± SD of 0.4 ± 7.3/−0.4 ± 5.5 mmHg (pregnancy) and −2.6 ± 7.0/0.8 ± 4.4 mmHg (preeclampsia) for systolic/diastolic pressure. Eighty-one percent of women did at least 6 measurements/day and all women did at least 2 measurements/week. Conclusion. The Microlife WatchBP Home is accurate for use in pregnancy and increases surveillance in compliant patients.

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

ObjectiveTo 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. MethodsNinety-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. ResultsThe 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). ConclusionThe 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.

Accuracy Assessment of the Dinamap ProCare 400 in Pregnancy and Preeclampsia

Objective. To assess the accuracy of the Dinamap ProCare 400 in pregnancy and preeclampsia, according to the British Hypertension Society protocol. Methods. Ethical approval was obtained. Forty-five women were recruited at two large teaching hospitals. Nine sequential same arm measurements were taken from each woman alternating between the Dinamap and mercury sphygmomanometry. Results. The device achieved an A/A grade (pregnancy) and an A/B grade (preeclampsia). Mean difference (SD) were 1.1(5.8)/0.1(5.7) mmHg (pregnancy) and –0.5(5.4)/0.9(9.5) mmHg (preeclampsia) for systolic/diastolic. Conclusion. The Dinamap ProCare 400 is recommended for use in pregnancy and has good accuracy in preeclampsia, although caution is still advised.

Accuracy assessment of the Tensoval duo control according to the British and European Hypertension Societies' standards

ObjectiveNoninvasive blood pressure (BP) measurement is dependent on either auscultation or oscillometry. The Tensoval duo control device uses auscultatory and/or oscillometric technology to determine BP. We evaluated the accuracy of this device in adults according to the British Hypertension Society (BHS) protocol and the International Protocol of the European Hypertension Society. MethodsEthical approval was obtained and participants gave written informed consent. Eighty-five participants who fulfilled the protocol criteria were recruited. Nine sequential same arm measurements were taken from each participant by two trained observers, comparing the device to mercury sphygmomanometery. Data analysis was performed according to the respective protocol guidelines. ResultsThe device achieved an A grade for both systolic and diastolic pressures with 68, 91 and 98% of systolic and 73, 91 and 98% of diastolic differences within the ≤5, ≤10 and ≤15 mmHg categories of the BHS protocol. It maintained an A/A grade throughout the low, medium and high-pressure analysis. It also achieved the requirements of the Association for the Advancement of Medical Instrumentation (ANSI/AAMI SP10 protocol) with a mean difference (SD) of −2.4 (6.0) mmHg for systolic and 0.9 (6.3) mmHg for diastolic pressure. It also passed all the phases of the International Protocol. ConclusionThe Tensoval duo control can be recommended for clinical and home care use in an adult population according to the criteria of the BHS protocol and the International Protocol. It is the first fully automated BP device for self-measurement to maintain an A/A grade throughout the low, medium and high-pressure ranges.

Accuracy validation of the Microlife 3AS1-2 blood pressure device in a pregnant population with low blood pressure

ObjectiveTo assess the accuracy of the Microlife 3AS1-2 blood pressure (BP) device in pregnant women with low BP to investigate suitability for hypotensive detection in low-income and middle-income countries. MethodsA prospective observational study was carried out evaluating the Microlife 3AS1-2, a hand-held, upper-arm, semiautomated BP device, according to British Hypertension Society (BHS) protocol methods. Thirty (stable) pregnant women with a clinical systolic BP less than 100 mmHg and/or diastolic BP less than 60 mmHg were recruited from antenatal wards and clinics and their BP was measured by three trained observers at a district-level hospital in South Africa. Accuracy was assessed according to the BHS grading criteria (A/B=pass) and the ANSI/AAMI/ISO standard for mean difference and SD (⩽5±8 mmHg). ResultsThe device achieved an A/A grade according to the BHS grading criteria. The mean difference±SD between the observer and the test device was 0.5±6.2 and 1.3±5.4 mmHg for systolic and diastolic BP, respectively, fulfilling the standard required by the ANSI/AAMI/ISO protocol. All observer differences were within 4 mmHg. ConclusionAccording to the BHS protocol, the Microlife 3AS1-2 BP device is accurate in pregnant women with low BP. The device has been validated previously in pregnancy and pre-eclampsia and also fulfils the criteria of the WHO for use in a low-resource setting. Although unstable women were not included in this validation (for safety and pragmatic reasons), this device could potentially improve the detection of shock secondary to obstetric haemorrhage or sepsis, as well as being used in pre-eclampsia, particularly in low-income and middle-income countries.

Blood pressure measuring devices: ubiquitous, essential but imprecise

Blood pressure measurement is an essential, poorly performed skill, traditionally undertaken through auscultation and use of a mercury sphygmomanometer. However, its exclusivity to the clinical environment has changed substantially over the last 20 years with the introduction of automated blood pressure devices. This simplified self-measurement method has enabled increased patient involvement and surveillance, while also eliminating the observer error, measurement bias and white-coat effect associated with auscultatory measurement in the clinical setting. Rapid advances in technology have decreased the discrepancy between automated and auscultatory readings, evidenced by the increased number of devices to pass recognized validation standards. However, the limitation of automated device accuracy is still evident in certain patient groups, such as those with diabetes, an arrhythmia or preeclampsia. Therefore, careful consideration is warranted when selecting a noninvasive blood pressure measurement device to ensure optimum accuracy and reliability of readings.

Clinical accuracy of a low cost portable blood pressure device in pregnancy and pre-eclampsia: the Nissei DS-400.

Hypertensive disorders of pregnancy cause significant maternal morbidity and mortality worldwide, particularly in developing countries. This study evaluated the accuracy of the Nissei DS-400, a low cost blood pressure (BP) device, in pregnancy according to the British Hypertension Society protocol. Forty-five pregnant women (15 with pre-eclampsia), were recruited from a large teaching hospital. Nine sequential same-arm BP measurements were taken from each woman by trained observers, alternating between mercury sphygmomanometry and the device. The Nissei DS-400 achieved the highest accuracy grade (A/A) in all subjects (n = 45) and in pregnancy alone (n = 30). The mean difference ± standard deviation between the standard and the device in pregnancy were −1.0 ± 5.1 mmHg and −1.1 ± 5.0 mmHg for systolic and diastolic BP, respectively, and −2.6 ± 5.9 mmHg and –3.4 ± 5.8 mmHg in all subjects. The Nissei-DS 400 can be recommended for clinical use in pregnancy and has potential as a good screening tool for pre-eclampsia in low resource settings.

Introduction of automated blood pressure devices intended for a low resource setting in rural Tanzania

Regular blood pressure (BP) monitoring is a cost-effective means of early identification and management of hypertensive disease in pregnancy. In much of rural sub-Saharan Africa, the ability to take and act on accurate BP measurements is lacking as a result of poorly functioning or absent equipment and/or inadequate staff education. This study describes the feasibility of using validated automated BP devices suitable for low-resource settings (LRS) in primary health-care facilities in rural Tanzania. Following a primary survey, 19 BP devices were distributed to 11 clinics and re-assessed at one, three, six, 12 and 36 months. Devices were used frequently with high levels of user satisfaction and good durability. We conclude that the use of automated BP devices in LRS is feasible and sustainable. An assessment of their ability to reduce maternal and perinatal morbidity and mortality is vital.