Worn on the wrist, new system will monitor blood pressure during sleep

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High blood pressure is the single biggest risk factor for heart disease, stroke and other health problems. The only way to know if you’re at risk is to have it checked often. While one in three American adults has high blood pressure, about 20 percent of people are unaware that they have it because it is largely symptomless. Researchers at Texas A&M University hope to help remedy this with a wrist-worn system that monitors blood pressure during sleep.

Roozbeh Jafari, a professor in the biomedical engineering, computer science and engineering, and electrical and computer engineering departments, and his team have received a $3.6 million grant from the National Institutes of Health (NIH) to create a system a user can wear all night while they sleep for constant readings. 

Blood pressure is the force of blood pushing against the walls of arteries as the heart pumps blood. High blood pressure, also referred to as hypertension, is when that force is too high and begins harming the body. If left untreated, it will eventually cause damage to the heart and blood vessels. Regular blood pressure monitoring systems use a mercury-based (or the digital equivalent) inflatable cuff-based sphygmomanometer. Many factors can affect blood pressure readings like caffeine, stress and exertion, and most people do not have theirs checked outside a doctor’s office.

“There is a significant need to understand how blood pressure fluctuates throughout the day and night,” said Jafari. “Nobody knows that, and there’s really no technology that can capture this continuously.”

Jafari said there is a value to measuring blood pressure continuously in the natural context of the user’s environment, especially during sleep, without being disturbed by the instrument. But the nature of the current cuff device allows for only infrequent measurements and its somewhat invasive nature and associated discomfort prohibits additional nocturnal measurements.

The objective of this research, a collaborative project with the Yale School of Medicine, is to create an unobtrusive, wrist-worn, cuffless blood pressure monitor for measurement and identification of nocturnal nondipping hypertension (when there’s a smaller decrease in nocturnal arterial blood pressure). The research, which began initially about three years ago, includes extensive validation with state-of-the-art ambulatory blood pressure monitors at nighttime in the presence of varied treatment models.

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