Hans van den Heuvel

3 DISCUSSION Key findings This validation study shows that both the iHealth Track and the Omron HEM-9210T automated BP devices fulfill the validation requirements of the revised 2010 International Protocol of the European Hypertension Society in a population of pregnant women, including a subgroup of pregnant women with preeclampsia. Previous studies validated the use of the iHealth Track and the Omron HEM-9210T in general populations using the ANSI/AAMI/ISO criteria. 12, 15 This validation study of a population subgroup ensures the accuracy of both devices when used in pregnancy. This allows the use of the two monitors in both clinical and home conditions of BP measuring in pregnancy. Validation in pregnancy and preeclampsia Altered hemodynamics of pregnant women are supposedly the reason for differences in BP readings compared to a general, nonpregnant population. 16 It is therefore recommended that, prior to standard clinical use, the device has been tested specifically in pregnant patients. As mentioned before, few automated devices have been validated for use in pregnancy. 17 Even more profound changes in hemodynamics can be found in pregnancies complicated with preeclampsia. Our study included 10 (out of a total of 33) women with preeclampsia and a wide range of blood pressure values up to 160 mmHg systolic and 110 mmHg diastolic. This resulted in a wider range of baseline blood pressure values, including severe hypertension, eventually leading to a more valuable report. However, this particular subgroup of 10 preeclampsia patients does not allow direct extrapolation to validation of these two devices in preeclampsia. Additional validation reports of these devices for the use in preeclampsia would be recommended. Home blood pressure monitoring in a pregnant population with (a high risk of) hypertensive disease is being used to detect hypertension in pregnancy, to evaluate the effects of the start or alterations of antihypertensive medication and to improve hypertension control with thresholds up to 160 systolic BP and 100 diastolic BP. As values exceed these thresholds, clinical evaluation is essential in order to assess symptoms of hypertensive disease and review changes in kidney and liver function as well as effects on the fetus. The use of the iHealth Track and Omron HEM-9210T is unlikely to prevent or postpone the onset of severe hypertension or preeclampsia, but may contribute to earlier detection, better BP control, reduction of burden and costs of hospital visits and admissions and greater patient satisfaction. Previous validation studies in preeclampsia patients of recent years show contrasting results. The Microlife 3BTO-A is validated for use in pregnancy complicated with preeclampsia but failed to pass the criteria of the International Protocol in a following study by Nouwen et al. several years later. 18, 19 In the same report, the Omron M7 passed for diastolic BP in preeclampsia, but failed for systolic BP measurements in the same study group. VALIDATION STUDY OF TWO BLOOD PRESSURE MONITORS IN PREGNANCY 49