There is poor agreement between manual auscultatory and automated oscillometric methods for the measurement of blood pressure in normotensive pregnant women

Abstract

Objective: To assess the agreement between manual auscultatory arterial blood pressure values and the values obtained by an automated oscillometric device in normotensive pregnant patients. Methods: Arterial blood pressure was determined concomitantly by a Dinamap 1846 sx/p device and by one observer (I, IV, V Korotkoff sounds) blinded to the Dinamap values. Agreement between methods was tested and graded according to the protocol of the British Hypertension Society. Results: A total of 490 observations were performed. Differences were observed between the manual auscultatory method and the Dinamap method. In monitoring normotensive pregnant patients with a Dinamap device, an error was made of about 10 mmHg in 22% of the observations for systolic arterial blood pressure (BP); in 11% for diastolic arterial BP (IV sound); and in 15% for diastolic arterial BP (V sound). According to the British Hypertension Society protocol, the overall grade reached was 'C'. Conclusions: Although an underestimation of only 10 mmHg was shown, this can be of great importance in delaying a correct diagnosis of pre-eclampsia. The assessment of agreement of the Dinamap 1846 sx/p device in hypertensive pregnant patients should also be determined. A prospective study could be useful to determine the effectiveness of an automated device in detecting hypertensive disease in pregnancy.