Validation of a solar powered blood pressure device, suitable for use in low resource settings

Hypertensive diseases in pregnancy are a significant cause of morbidity and mortality, particularly in low resource settings (LRS). Pre-eclampsia and eclampsia alone claim up to 50 000 women's lives globally each year, with an estimated fetal case death of 7–25% in African countries.1 Accurate and regular antenatal blood pressure (BP) monitoring is a cost effective means for early identification and management of hypertensive disease in pregnancy. No BP devices suitable for use in LRS have been assessed for accuracy in pregnancy. Aim To evaluate the accuracy of the semi-automatic Omron HEM-Solar BP device in pregnancy and pre-eclampsia according to the British Hypertension Society (BHS) protocol. Methods Pregnant women were recruited from St Thomas' Hospital (UK) and Kimberley Hospital Complex (South Africa). Trained observers took nine sequential same-arm BP measurements from each woman, alternating between mercury sphygmomanometry and the device. Data were analysed according to BHS guidelines, requiring an A or B grade (for both systolic and diastolic pressures) to pass. Results The device achieved an A/B grade in pregnancy (n=30) including five women with pre-eclampsia. The mean difference (SD) between observers and device was −4.0(5.8) mm Hg and −0.1(8.5) mm Hg for SBP and DBP respectively. Conclusion The Omron HEM-Solar can be recommended for clinical use in pregnancy. Low cost, ease of use and solar power make it ideally suited to a LRS for use by skilled and unskilled health workers. It has the potential to facilitate early diagnosis of pre-eclampsia and address the disproportionate burden of maternal and infant morbidity in LRS.