Researchers at Worcester Polytechnic Institute (WPI) are developing a sensor the size of a Band-Aid that will measure a baby’s blood oxygen levels, a vital indication of the lungs’ effectiveness and whether the baby’s tissue is receiving adequate oxygen supply. Unlike current systems used in hospitals, this miniaturized wearable device will be flexible and stretchable, wireless, inexpensive, and mobile — possibly allowing the child to leave the hospital and be monitored remotely. The sensor measures blood gases diffusing through the skin and reports the data wirelessly.
Studies have shown that babies’ health improves when they are with their families. Therefore, their goal with this affordable, mobile device is to give doctors more flexibility in monitoring their patients both in the hospital and at home.
Typically, measuring oxygen molecule levels transcutaneously involves using a system with an approximately 5-pound monitor plugged into an electrical outlet, and sensors that are generally wired to the monitor. This new healthcare 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, or the partial pressure of oxygen, which indicates the amount of oxygen dissolved in the blood — a more accurate indicator of respiratory health than a simple oxygen saturation measurement that can be easily taken with a pulse oximetry device gently clamped on a finger. And measuring the PO2 level via a noninvasive device attached on the skin is as accurate as a blood test.
The wearable baby oxygen monitor also would be useful for adults, especially people with severe asthma and seniors with or Chronic Obstructive Pulmonary Disease (COPD), which is an incurable, progressive lung disease. It is the third leading cause of death in the United States, according to the Centers for Disease Control and Prevention. The researchers intend to modify the wearable for adults, and create a related smartphone app, in another phase of their research.
The chip, designed to work inside the wearable oxygen monitor, activates the optical sensors, captures analog signals from the sensor, handles power management, and contains required circuitry. The team has custom designed the individual circuits, such as signal capturing circuits and driver circuits for optical based readout. In the next phase of the research project, they plan to equip the chip with circuitry to digitize the analog signals, transmit the captured and digitized data, and create power from a wireless link. At that point, it will be a complete system on a chip.