Wearable electronics for continuous cardiac, respiratory monitoring

January 12, 2021

WASHINGTON, January 12, 2021 -- A highly sensitive wearable sensor for cardiorespiratory monitoring could potentially be worn continuously by cardiac patients or others who require constant monitoring.

The small and inexpensive sensor, announced in Applied Physics Letters, by AIP Publishing, is based on an electrochemical system involving two ionic forms of iodine, I- and I3-. A solution containing these electrolyte substances is placed into a small circular cavity that is capped with a thin flexible diaphragm, allowing detection of subtle movements when placed on a patient's chest.

Small motions that arise from the heartbeat and breathing cause the flexible diaphragm to move the I-/I3- solution into a narrow channel in the device, where it is electrochemically detected by four platinum electrodes.

"The sensor body was fabricated using Ecoflex 00-20, which has proven to be a very soft, strong and stretchy silicone rubber that is widely used in medical simulation, orthotics, and prosthetics," said author Yong Xu.

The investigators created a mold for the circular chamber and the associated narrow channel using 3D printing. A solution to create Ecoflex 00-20 was poured into the mold to form the body of the sensor and was also spin-coated on a rapidly rotating disk to produce the thin diaphragm. After the diaphragm and chamber body were bonded together, the investigators used a syringe to fill the chamber with the electrolyte solution.

The resulting device is only 28 millimeters wide and is skin-safe, so it can be attached directly to the patient's body. The device was able to detect the heartbeat with high sensitivity. A signal-to-noise ratio of greater than 6:1 was achieved, which is considered good.

Respiration can be detected by this device in two different ways. Because of the sensor's stretchability, it deforms when the chest contracts and expands during breathing, functioning as a strain sensor. The other way the sensor detects respiration is due to the way the volume of the chest cavity changes during a breath, modulating the heartbeat signal. In this way, respiration is detected indirectly through changes in the heartbeat.

The authors suggest their sensor could potentially be used for diagnosis of respiratory diseases, such as COVID-19, which often leads to shortness of breath.

"Symptoms in the early stage of infection could be subtle," said Xu. "Wearable devices that are capable of accurate detection of subtle respiratory and cardiovascular variation are of great interest especially during the current pandemic."
The article, "A wearable mechano-acoustic sensor based on electrochemical redox reaction for continuous cardiorespiratory monitoring," is authored by Zhiguo Zhao, Xiaoce Feng, Xiaoyu Chen, Lenore L. Dai, and Yong Xu. The article will appear in Applied Physics Letters on Jan. 12, 2021 (DOI: 10.1063/5.0029108). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0029108.


Applied Physics Letters features rapid reports on significant discoveries in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See https://aip.scitation.org/journal/apl.

American Institute of Physics

Related Cardiac Patients Articles from Brightsurf:

Cardiac arrest is common in critically ill patients with COVID-19
Cardiac arrest is common in critically ill patients with covid-19 and is associated with poor survival, particularly among patients aged 80 or older, finds a study published by The BMJ today.

New risk tool developed for cardiac arrest patients
Experts have developed a risk score to predict cardiac arrest patient outcomes.

Autopsies reveal surprising cardiac changes in COVID-19 patients
A series of autopsies conducted by LSU Health New Orleans pathologists shows the damage to the hearts of COVID-19 patients is not the expected typical inflammation of the heart muscle associated with myocarditis, but rather a unique pattern of cell death in scattered individual heart muscle cells.

Levothyroxine doesn't improve cardiac function for heart attack patients
Tens of thousands of patients with underactive thyroid are being prescribed Levothyroxine after a heart attack - but the results a of a double-blind randomised clinical trial has shown that it offers no benefits to their heart function.

Critically ill COVID-19 patients are 10 times more likely to develop cardiac arrhythmias
Patients with COVID-19 who were admitted to an intensive care unit were 10 times more likely than other hospitalized COVID-19 patients to suffer cardiac arrest or heart rhythm disorders, according to a new study.

How commonly do patients develop persistent opioid use after cardiac surgery?
A large, national database was used to determine how common it was for patients who hadn't used opioids before undergoing a coronary artery bypass grafting or heart valve procedure to subsequently develop persistent opioid use after surgery.

Only 1 in 4 Medicare patients participate in cardiac rehabilitation
Only about 24% of Medicare patients who could receive outpatient cardiac rehabilitation participate in the program.

Getting to the heart of epinephrine use in pediatric cardiac arrest patients
The effectiveness of epinephrine treatment during resuscitation of adult patients with cardiac arrest is generally promising, but little is known about its effects in pediatric patients.

How do outcomes for in-hospital cardiac arrest differ in patients treated with dialysis?
Among patients who experience cardiac arrest while in the hospital, those on dialysis were less likely to have a shockable rhythm and more likely to be outside of the intensive care unit at the time of arrest compared with patients not on dialysis.

Intermittent fasting increases longevity in cardiac catheterization patients
In a new study by researchers at the Intermountain Healthcare Heart Institute in Salt Lake City, researchers have found that cardiac catheterization patients who practiced regular intermittent fasting lived longer than patients who don't.

Read More: Cardiac Patients News and Cardiac Patients Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.