The Evaluation of Wearable Cuff-less Blood Pressure Measuring Devices

This project deals with the development of a new standard for evaluating the cuff-less wearable blood pressure (BP) measuring devices. The reasons for this need are as follows: (1) the present studies show that the existing evaluation methods for validating the conventional BP devices do not agree with each other in all circumstances; and (2) the protocols set up for conventional devices fall short of accurate evaluation for the newly developed wearable BP measurement devices, since the new devices use completely different measurement techniques from those of the conventional cuff-based ones. These cuff-less techniques enable the new devices not only to be noninvasive, miniature in size, low-power consumption, cost-effective, and durable but also to have the potential to measure the beat-to-beat continuous BP. To analyze the measuring accuracy of a wearable cuff-less BP device, a total of 999 datasets from 85 subjects were collected. As the BP decreased, an obvious decrease of the variation in the measurement error was observed. This phenomenon may have been caused by the new technique that the device uses. It leads to some difficulties in evaluating the performance of cuff-less BP devices by some existing standards. In order to remove or reduce this unwanted trend, a transformation method was carefully examined. Based on the transformed datasets, traditional evaluation approaches are then applicable.