Researchers at Monash University in Australia have developed a wearable device that can continuously monitor blood pressure during a variety of activities including while exercising and during sleep. The technology does not require uncomfortable inflatable cuffs or invasive measurements, and uses continuous wave radar and photoplethysmogram sensors to monitor blood pressure. “For close to a century, the health sector has used the cuff device to measure blood pressure. More invasive measures are used to monitor the continuous blood pressure of critically ill patients, which are uncomfortable and could potentially cause infection due to ischemia,” said Mehmet Yuce, a researcher involved in the study. Using traditional cuff systems to measure blood pressure comes with significant drawbacks – the cuff inflation is uncomfortable, and cannot provide continuous measurements. “Clinicians still cannot continuously measure blood pressure during sleep, nor during times of activity such as walking or running. This means people with high, low or irregular blood pressure can’t get the critical information they need about the state of their health around the clock,” said Yuce. To address this, these Monash researchers turned to another technology to provide continuous blood pressure measurements – radar. Their solution is a wearable blood pressure monitor that consists of a continuous wave radar (CWR) sensor placed on the sternum, and a photoplethysmogram (PPG) sensor placed on the left earlobe. The sensors allow the researchers to calculate a number of hemodynamic parameters from which they can estimate blood pressure, including pulse transit time and the pre-ejection period. Crucially, the technique allows for continuous monitoring, is non-invasive, and is much less cumbersome than traditional cuff measurements, while allowing measurements during exercise and rest. So far, the researchers have tested their device in a group of 43 volunteers and found that it was 93% accurate in measuring blood pressure in those completing posture tasks, as well as 83% accurate during exercise. “The CWR sensors present a low-power, continuous and potentially wearable system with minimal body contact to monitor aortic valve activities directly. Doctors would be interested to see such information for long-term better diagnosis of their patients,” said Yuce. “Results of this study demonstrate the potential superiority of CWR-based PEP extraction for various medical monitoring applications, including blood pressure monitoring.” Source
