Blood Flow Measuring Patches Make Waves in Medical Field


Joanne Rhee
Staff Writer

Great advancements have been made in the medical world in recent years. Adding to the growing list of innovation is John Rodgers, a material science and engineering professor at the University of Illinois at Urbana-Champaign, who has developed a skin patch that easily monitors blood flow.

The “epidermal electronic” sensor system conforms to skin, and contains heat sensors that track the movement of heat. This information is then entered into an algorithm to assess blood flow in the veins, arteries and capillaries.

The device works by imperceptibly heating up the skin, and then recording the movement of that heat. Imagine, for example, that the heating element is positioned over an artery or vein near the skin’s surface. After the device heats the skin, the blood in that vessel carries the heat away; then temperature sensors, arranged in rings around the heating element, record the direction and amount of the heat as it moves. By combining that information with models that account for the fluid dynamics of blood flow “you can quantitatively determine flow rate,” says Rogers.

According to the research report, “Although a variety of techniques exist, most require complete immobilization of the subject, thereby limiting their utility to hospital or clinical settings. Those that can be rendered in wearable formats suffer from limited accuracy, motion artifacts and other shortcomings that follow from an inability to achieve intimate, noninvasive mechanical linkage of sensors with the surface of the skin.”

Before this revolutionary patch, there had been two main ways to measure blood flow. The first utilized a Doppler ultrasound. It measures whether blood is flowing away or towards the sensor, and the velocity at which it moves. The downside of this is that sometimes results and measurements can be distorted or indistinguishable. It also doesn’t work well with capillaries.

The other main method is photoacoustic imaging, which uses infrared lasers to create a temporary wave of pressure that can be tracked by sensors. However, this method doesn’t show the movement of blood as a continuous stream.

This breakthrough is great because it offers convenience and accuracy. The patches are also cost efficient and non-invasive. This is just the newest advancement in the recent trend of patch technology.

Cardiac monitors in the form of patches allow patients to measure heart rate with ease. One example is the ZIO® Patch, which is easily accessible to the public and can be worn long term. It can be used in conjunction with phones, tablets and computers to monitor heart rate.

In addition, there is a patch that can also continuously measure blood pressure. Instead of putting an inflatable monitor on your arm and having the nurse pump away until you’re sure she’s cut off your circulation, you can apply the small patch directly over your heart. The patch picks up heartbeats and electrical impulses, and can be used continuously.

Patches in the medical field aren’t limited to weaning off nicotine or birth control. There are many applications for patches, many of which are cost-efficient and easier to use. The blood flow measuring patch is just the next step towards having a decorated body full of snazzy medical patches.