Neonatal PPG Heart Rate Monitoring System
Senior Capstone Design
About 10% of neonatal patients require some form of resuscitation immediately after birth to regulate their heart rate. Currently, there is not a consistently accurate method of measuring a newborns heart rate. My capstone group and I have designed a cost efficient and light weight prototype using an Arduino pro micro and a Gravity PPG sensor. The final product accurately measures heart rate and has a final size of 1.3 x 1.6 inches.
First Prototype
The device uses an averaging algorithm to calculate the beat-to-beat heart rate so it will fluctuate frequently. This allows for a more accurate and real time feedback for the physician. By testing and refining the software, we were able to reduce the boot up time by 125% and display a heart rate 50% quicker. The display time is vital when considering the life or death uses of this device.
Schematic
The PPG uses green light (750 nm) to detect blood flow within the supraorbital and supratrochlear arteries. The analog information is run through an analog to digital converter (ADC) and processed to calculate heart rate. The heart rate is shown on an organic light emitting diode (OLED) display and LED.
Preliminary Data
We compared our device to a 3 lead Electrocardiogram (ECG) and yielded desirable results. The figure below shows the PPG and ECG beat to beat heart rate differential. On average, our design and algorithm was able to have a differential +/- 10 bpm. By the fourth registered heart beat, our results on par with the ECG. Further testing is still being conducted.
