A sensor the size of a Band-Aid can 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 is flexible and stretchable, wireless, inexpensive, and mobile — possibly allowing the child to leave the hospital and be monitored remotely.
Typically, measuring oxygen molecule levels transcutaneously involves using a system with an approximately 5-pound monitor plugged into an electrical outlet and sensors that generally are wired to the monitor. The new device uses wireless power transfer and is 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, which 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 Chronic Obstructive Pulmonary Disease (COPD), which is an incurable, progressive lung disease.
A chip would act as the heart for the wearable device. 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 individual circuits, such as signal capturing circuits and driver circuits for optical based read-out circuits, were custom designed. In the next phase of the research project, the chip will be equipped with more circuitries 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 the chip.