image: A patient gets their blood pressure checked by a doctor. view more
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Geckos can stick to just about anything, and their feet are helping Pitt researchers revolutionize how medical professionals can monitor blood pressure.
The small reptilians' toe pads are covered in thin hairs called setae, which is what adheres to surfaces. Feng Xiong, an associate professor of electrical and computer engineering, and his team are using gecko feet to improve the adhesion of cuff-less 24-hour ambulatory blood pressure monitoring. This research will be funded for $580,000 through the National Institute of Health (NIH) over the next three years.
“Blood pressure is hard to track longitudinally,” Xiong explained. “Patients, for example, are likely to be more stressed when inside a doctor’s office, likely creating higher blood pressure readings than normal, which is why 24-hour monitoring is important.”
Cuff-based devices are most commonly used to track changes in blood pressure, as well as diagnose hypertension, but the devices come with their own set of limitations. The cuff periodically inflates and deflates every 15 minutes or so, even when the patient is trying to sleep. Monitoring blood pressure during sleep is crucial for medical professionals, but interrupting patients’ sleep can cause misreadings during clinical observation.
Cuffless blood pressure monitoring devices would not only improve patient sleep, but provide medical professionals with a more effective clinical approach to diagnosing hypertension.
Partnering with the University of Pittsburgh School of Medicine, Xiong is joined by co-investigators Ramakrishna Mukkamala, associate professor of bioengineering and anesthesiology, and Matthew Muldoon, professor of medicine. Aman Mahajan, professor of anesthesiology and perioperative medicine, and Sanjeev Shroff, interim dean of the Swanson School of Engineering, will serve as faculty associates.
Together, the team will design wearable tonometric sensors at arterial sites on the neck and ankle which will collect tonometric waveforms and pulse transit time (PTT) – or the time it takes for the pulse to travel between two arterial sites – simultaneously. Ultimately, the team plans to combine high-fidelity arterial tonometry and PTT principles to achieve cuffless 24-hour blood pressure monitoring.
“We will be challenging existing barriers with a number of innovations,” Xiong explained. “These include integrating ionic liquid and microstructures in the sensor to enhance both the sensitivity and dynamic range, mimicking the feet of geckos at the sensor substrate for better adhesion, and develop PTT-based calibration to extract both diastolic and systolic blood pressure.”
Muldoon said this research is needed to help patients struggling with hypertension as well as for the doctors trying to diagnose it.
“Xiong’s lab seeks to catapult research on devices to measure blood pressure in the hospital and at home every minute without noise or pain,” said Muldoon.
The goal of the research is that more accurate readings from cuffless blood pressure monitors will lead to improved hypertension diagnosis, better post-surgery hypotension surveillance, and fewer cardiovascular disease mortalities.