Sequence diagram (click to view the full diagram)

Think of PulsePatch as a “radar” for electromagnetic interference in the operating room. Just like a radar detects invisible signals in the air, PulsePatch senses surrounding electromagnetic activity that surgeons normally can’t see. A loop antenna inside the device picks up these signals and converts them into an electrical reading that a small microcontroller processes in real time.

The device then translates this invisible information into a simple traffic-light LED display, allowing surgeons to instantly understand whether EMI levels are low, moderate, or high at a glance. PulsePatch is sealed in a sterile enclosure and includes built-in shielding materials that both reduce electromagnetic interference as well. 

Some surgical tools, particularly those using high-frequency electrical currents, create electromagnetic interference (EMI) that can induce inappropriate shocks in patients with implanted cardiac devices.

Current standards of care include placing a magnet to disable device therapies or calling in a specialist to reprogram the device. These approaches take away valuable time and resources in an operating room setting. 

To monitor and mitigate intraoperative EMI affecting implanted devices in cardiac surgery, minimizing innappropiate shocks and inhibitons. 

“The magnet can fall… [and] reprogramming the device involves calling extra people to come do it. Smaller hospitals might not have as many of those people available.”
— Dr. Edward O’Leary, MD, Cardiologist and Electrophysiologist, BCH

“The biggest challenge is coordination and availability, not actual programming itself.”
— Dr. Mohammed Gabr, Cardiologist, BWH

All the electronics and shielding layers were assembled on Onshape. Both the enclosures were 3D printed where the shielding and electronics enclosure was printed in TPU (more flexible so it sits better on the patient’s body) and ABS respectively (rigidity needed for heavier weight of electronics). 

The Engineering Drawings were created using ANSI standards

For detection, we placed the radiating loop at varying distances from the antenna, recording the ADC values and LED status, expecting to see an increase in ADC as distance decreased. 

We built a tissue–pacemaker surrogate model to test the "attentuation" function. A silicone sponge soaked in PBS simulated the conductivity and dielectric properties of human skin/tissue. Copper mesh disperses electric fields & ferrite sheet above attenuates the magnetic fields. Lastly, an aluminum sheet beneath the sponge acted as a conductive pacemaker surrogate. Positioning the loop at varying distances we collected data for 3 trials with and without the shield, expecting to see a reduction in ADC values for the shielding.”

We learnt about FMEA as a tool for proactively assessing design risks by analyzing potential failure modes, their effects, and causes, allowing us to make informed design trade-offs before physical testing.