今井 靖

An increase in short-term blood pressure (BP) variability is a characteristic feature in the elderly. It makes the management of hemodynamics more difficult, because it is frequently seen disturbed baro-reflex function and increased arterial stiffness, leading to isolated systolic hypertension. Large BP variability aggravates hypertensive target organ damage and is an independent risk factor for the cardiovascular (CV) events in elderly hypertensive patients. Therefore, appropriate control in BP is indispensable to manage lifestyle-related diseases and to prevent subsequent CV events. In addition, accumulating recent reports show that excessive BP variability is also associated with a decline in cognitive function and fall in the elderly. In the clinical settings, we usually evaluate their health condition, mainly with single point BP measurement using cuff inflation. However, unfortunately we are not able to find the close changes in BP by the traditional way. Here, we can show our advantageous approach of continuous BP monitoring using newly developing device `wearable BP sensing' without a cuff stress in the elderly. The new device could reflect systolic BP and its detailed changes, in consistent with cuff-based BP measurement. Our new challenge suggests new possibility of its clinical application with high accuracy.

Blood pressure monitoring in daily life is important from a perspective of lifestyle-related diseases prevention. Conventional ambulatory blood pressure monitoring (ABPM) device can measure blood pressure at regular interval for 24 hours. However, it is limited by long measuring time, low sampling rate, and constrained posture. We developed a wearable sensor for monitoring a continuous blood pressure using the pulse wave velocity method. Results of exercise test by an ergometer show its effectiveness. A mobile software in a smart phone is in charge of controlling data acquisition, displaying general information and signals for real-time monitoring, and sending data to the database server. In this paper, we report sensor development and discuss pilot study results in a hospital.