New wearable could replace auscultation with a stethoscope

Body sounds tell us a lot about our state of health, whether they come from our heartbeat, our breathing or even food traveling through the digestive tract. Researchers at Northwestern University in the United States have presented a wearable device that, when gently adhered to the skin, can continuously track these sounds in practically any region of the body.

Pilot studies evaluated the use of the device in 15 premature babies with respiratory and gastrointestinal disorders and in 55 adults, 20 of whom had chronic lung diseases. According to the researchers, the results showed not only clinical accuracy, but also revealed more functionality than expected.

“Currently, there are no methods for continuously monitoring and mapping body sounds at home or in hospital environments. You have to use a conventional or digital stethoscope in different parts of the chest and back to listen to the lungs. In close collaboration with clinical teams, we decided to develop a new strategy to monitor patients in real time, continuously and without the problems associated with bulky, rigid and wired technological solutions,” says John A. Rogers, bioelectronics researcher at Northwestern University.

The idea behind the device is to enable continuous and highly accurate assessment of health conditions and support decision-making when patients are hospitalized and, for example, connected “One of the main advantages of this type of device is being able to auscultate and compare different regions of the lungs. Simply put, it’s like having 13 highly trained doctors listening to different regions of the lungs simultaneously with their stethoscopes, and their minds are synchronized to create a continuous and dynamic assessment of lung health translated into a real movie on the computer screen,” explains Dr. Ankit Bharat, thoracic surgeon at Northwestern University.

The wearable device uses pairs of high-performance digital microphones and accelerometers and adheres them to the skin to create a non-invasive sensing network. By capturing the sounds and correlating them to bodily processes, it can spatially map how air flows into, through and out of the lungs, the heart rhythm or how food and fluids move through the intestines.

Measuring 40 millimeters long, 20 millimeters wide and 8 millimeters thick, it uses a flash memory unit, a small battery, electronic components and Bluetooth capabilities. An algorithm can separate external sounds (environmental or from neighboring organs) and internal body sounds.

First tests

When developing the new device, the researchers had two vulnerable groups in mind: premature babies with respiratory complications in the neonatal intensive care unit and adults in post-surgical conditions.

In premature babies, apneas are one of the main causes of prolonged hospitalization and even death. However, there are currently no methods for continuously monitoring airflow at the bedside and accurately distinguishing between apnea subtypes. Many babies are even smaller than a stethoscope, so they are technically difficult to monitor.

In studies carried out at the Montreal Children’s Hospital in Canada, the devices were placed in babies at the base of the throat and successfully detected the presence of airflow and chest movements, being able to estimate the degree of airflow obstruction with high reliability.

The researchers also used the device to monitor bowel sounds in other premature babies in four positions on the abdomen to detect gastrointestinal problems, which, in particular, are accompanied only by reduced bowel sounds, but can be used as an early warning sign of poor digestion and possible obstructions.

In another study, the device was tested on adult patients, 35 of whom had chronic lung disease and 20 of whom were healthy. Lung sounds and body movements were captured in various positions simultaneously, making it possible to analyze breathing in various regions of the lungs.

“The lungs can emit all kinds of sounds, such as crackles and wheezes. It’s a fascinating microenvironment. By continuously monitoring these sounds in real time, we can determine whether lung health is improving or worsening and assess how well a patient is responding to a particular drug. We will then be able to personalize treatments individually,” Bharat celebrates.