Wearable wireless sensor monitors baby blood oxygen

Researchers are developing a wearable sensor to measure a baby’s blood oxygen levels, a vital indication of the lungs’ effectiveness and whether the baby’s tissue is receiving enough oxygen.

blood oxygen
Prof Ulkuhan Guler shows off an early prototype of the miniaturised, wearable device that will one day monitor infants’ blood oxygen levels (Image: WPI)

Prof Ulkuhan Guler, assistant professor of electrical and computer engineering and director of Worcester Polytechnic Institute’s Integrated Circuits and Systems Lab, is leading the project focused on enabling sick, hospitalised babies to be untethered from wired sensors, so they can be examined more easily and frequently, held, and even allowed to go home. The team’s device measures blood gases diffusing through the skin and reports the data wirelessly. According to WPI, the miniaturised wearable device will be flexible and stretchable, wireless, and inexpensive.

“Extended stays in the hospital are costly and can be a strain on families,” Guler said in a statement. “And studies have shown that babies’ health improves when they are with their families. Our goal with this affordable, mobile device is to give doctors more flexibility in monitoring their patients both in the hospital and at home.”

CYRIL shines a light on the brains of newborn babies

Incubation innovation: saving babies’ lives

Measuring oxygen molecule levels transcutaneously typically involves using a system with an approximately 5lb monitor plugged into an electrical outlet, and sensors that generally are wired to the monitor. Guler’s device will use wireless power transfer. It also will be connected to the internet wirelessly so an alarm on a monitor in a doctor’s office or smartphone app would notify medical personnel and family members if the baby’s oxygen level begins to drop.

The device is designed to measure PO2 (partial pressure of oxygen), which indicates the amount of oxygen dissolved in the blood – a more accurate indicator of respiratory health than oxygen saturation measurements, which can be taken with a pulse oximetry device clamped on a finger. According to WPI, measuring PO2 levels via a non-invasive device attached on the skin is as accurate as a blood test.

Guler is collaborating with Pratap Rao, associate professor of mechanical engineering at WPI, and Lawrence Rhein, MD, chair of the department of paediatrics and an associate professor at the University of Massachusetts Medical School. Ian Costanzo and Devdip Sen, graduate students in electrical and computer engineering at WPI, also are working with Guler to create a chip for the wearable device.

The chip activates the optical sensors, captures analogue signals from the sensor, handles power management, and contains required circuitry. Guler and the team have custom designed the individual circuits, such as signal capturing circuits and driver circuits for optical-based read-out circuits. In the next phase of the project, they plan to equip the chip with more circuitry to digitise the analogue signals, transmit the captured and digitised data, and create power from a wireless link.