Researchers at the University of Pittsburgh are pioneering a novel approach to blood pressure monitoring by utilizing the devices we carry with us every day.
Ramakrishna Mukkamala, a bioengineering professor at Pitt’s Swanson School of Engineering, is dedicated to developing user-friendly blood pressure (BP) measurement systems. Instead of developing a new medical gadget to monitor blood pressure, Mukkamala decided to take advantage of something almost everyone has in their pockets: smartphones, and figure out how to detect blood pressure using sensors already integrated into them.
“The most significant thing you can do to reduce your risk of cardiovascular disease is to lower high blood pressure through lifestyle changes, but in underserved populations, many people don’t have access to blood pressure cuffs, regular doctor’s appointments, or even know it’s a problem,” Mukkamala said. “But they do have smartphones.”
Mukkamala’s team used resources included in most cellphones, such as motion-sensing accelerometers, front cameras, and touch sensors, to create an Android smartphone app that can assess a person’s pulse pressure.To take a measurement, the user raises his or her hand while holding the smartphone. The findings of the project “A smartphone application toward detection of systolic hypertension in underserved populations,” published in Scientific Reports, show that a promising new technology could help reduce the global burden of systolic hypertension, particularly among underserved populations.
Development of a cuffless blood pressure measurement device that does not require any external calibration is the holy grail – such a device currently does not exist. The research work reported in this publication is an important step in the right direction, and is also encouraging for additional work aimed at obtaining systolic, diastolic, and mean pressures.
Sanjeev Shroff
Designing blood pressure technology for a touchscreen
Turning a smartphone into a monitoring device is not a simple feat, as Vishaal Dhamotharan, a graduate student in the Cardiovascular Health Tech Laboratory, discovered after numerous app versions. Because cellphones lack force sensing tools, a critical aspect of the project was determining how to duplicate the results of a typical blood pressure assessment using only a cell phone, which the team accomplished by employing a familiar force: gravity.
“Because of gravity, there’s a hydrostatic pressure change in your thumb when you raise your hands up above your heart, and using the phone’s accelerometer, you’re able to convert that into the relative change in pressure.” Dhamotharan spoke.
By pairing this hand-raising motion with guided thumb maneuvers on the smartphone, the team was able to calculate each participant’s pulse pressure. Pulse pressure is the difference between your upper (systolic) and lower (diastolic) numbers — for example, an individual with a BP measurement of 120/80 has a pulse pressure of 40. For Sanjeev Shroff, collaborator and bioengineering department chair, this publication is a promising advancement for blood pressure measurement devices.
“Development of a cuffless blood pressure measurement device that does not require any external calibration is the holy grail — such a device currently does not exist,” Shroff said. “The research work reported in this publication is an important step in the right direction, and is also encouraging for additional work aimed at obtaining systolic, diastolic, and mean pressures.”
Although pulse pressure is not commonly employed in cardiovascular disease monitoring, the study demonstrated its importance as a metric for diagnosing hypertension, according to Céderick Landry, an assistant professor at the University of Sherbrooke and former postdoctoral researcher in the lab.
“Guidelines typically require doctors to measure both systolic and diastolic blood pressure, and pulse pressure is just the difference between the two.” Landry stated. “We showed that if you only have access to pulse pressure, it’s still very correlated with hypertension, so part of our challenge now is changing the mentality on how to best measure things.”
Hypertension management within reach
Systolic hypertension, or high blood pressure, affects more than 4 billion adults worldwide and is the leading modifiable risk factor for cardiovascular disease, the top cause of death globally. This app could bring blood pressure monitoring software to any smartphone owner, enabling consistent self-monitoring and easy sharing of results with healthcare providers. This innovation is especially promising for managing hypertension, which can often be lowered through lifestyle changes such as reducing salt intake, quitting smoking and exercising regularly.
“This app would be really useful in low-income settings where people may not even have existing access to blood pressure tools.” Dhamotharan spoke. “Being able to measure blood pressure more frequently would allow an individual to track any significant changes in blood pressure, monitor for hypertension, and be able to manage their conditions with that knowledge.”
People in rural areas of the United States are 40% more likely than urban inhabitants to suffer heart disease, therefore this technology could be critical for giving accessible healthcare resources to communities in the United States and around the world. Looking ahead, Mukkamala’s team is striving to improve smartphone blood-pressure monitoring so that it can reach those who need it the most.
“The research is here — we just need some help making the technology better.” Landry said. “This is the first method of its kind, and even better, it’s something that we can start implementing right now.”
