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This prospective observational study aimed to identify at presentation the maternal hemodynamic and demographic variables associated with a therapeutic response to oral labetalol and to use these variables to develop a prediction model to anticipate the response to labetalol monotherapy in women with hypertension. It was set at a maternity unit in a UK teaching hospital. Maternal demographic data from 50 pregnant women, presenting with hypertension between January and August 2013, was collected and blood pressure measured with a device validated for pregnancy and pre-eclampsia. Maternal haemodynamics were assessed with a bioreactance monitor. Participants were commenced on oral labetalol, and reviewed until delivery and discharge home. Logistic regression analysis was performed to assess the prediction of response to labetalol according to the maternal demographic and hemodynamic variables. Main outcome measures were the response to labetalol monotherapy up to delivery and discharge home, defined as sustained blood pressure control <140/90, and the rates of severe hypertension. Thirty-seven women (74%) had their blood pressure well controlled with labetalol monotherapy, 13 (26%) failed to achieve control with labetalol alone, of whom 9 developed severe hypertension. Multivariate logistic regression showed that heart rate, ethnicity and stroke volume index were independent predictors of the response to labetalol. The predictive accuracy of the model was 96% (95% confidence interval (CI) 86-99%). Maternal demographics and haemodynamics are potent predictors for the response to labetalol, and these parameters may guide therapy to enable effective blood pressure control and a lowering of severe hypertension rates.

The study aimed to develop prediction algorithms for hypertensive disorders based on multivariate analysis of factors from the maternal history and compare the estimated performance of such algorithms in the prediction of early preeclampsia (PE), late-PE and gestational hypertension (GH) with that recommended by the National Institute for Clinical Excellence (NICE). Logistic regression analysis was used to determine which of the maternal characteristics and history had significant contribution in predicting early-PE, late-PE and GH. There were 37 cases with early-PE, 128 with late-PE, 140 with GH and 8061 cases that were unaffected by PE or GH. Predictors of early-PE were Black race, chronic hypertension, prior PE and use of ovulation drugs. Predictors of late-PE and GH were increased maternal age and body mass index, and family history or history of PE. Additionally, late-PE was more common in Black, Indian and Pakistani women. The detection rates of early-PE, late-PE and GH in screening by maternal factors were 37.0, 28.9 and 20.7%, respectively, for a 5% false positive rate. Screening as suggested by NICE would have resulted in a false positive rate of 64.1% with detection rates of 89.2, 93.0 and 85.0% for early-PE, late-PE and GH, respectively. Meaningful screening for hypertensive disorders in pregnancy by maternal history necessitates the use of algorithms derived by logistic regression analysis.

Mercury-independent devices are increasingly being used in clinical practice as mercury will soon be removed from clinical use as a result of environmental, health and safety concerns. The aim of this study was to evaluate the accuracy of a portable aneroid device in an adult population at high altitude by following the part of the protocol of the British Hypertension Society regarding comparison between device and observer. We examined 10 subjects in Cerro de Pasco, Peru, which is situated 4370 m above sea level. The aneroid device was initially calibrated at both high altitude and at sea level to ensure optimal function. Validation of the device was undertaken at high altitude by connecting it in parallel to two mercury sphygmomanometers. Eleven sequential same-arm measurements were taken from each subject by two trained observers, alternating between mercury sphygmomanometry and the aneroid device. Simultaneous mercury readings were also recorded for additional analysis. During calibration, all 60 comparisons between the aneroid and mercury sphygmomanometers were within 3 mm Hg both at sea level and at high altitude. At validation, the device achieved an A grade for both systolic and diastolic pressures and also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The mean and standard deviation for systolic and diastolic pressures, respectively, were -1.32 (4.3) mm Hg and 3.7 (4.7) mm Hg in sequential analysis and -0.7 (2.6) mm Hg and -3.3 (2.7) mm Hg in simultaneous analysis. We conclude that the Riester-Exacta portable aneroid device can be recommended for use in an adult population at high altitude.