Skin No Barrier For Cardiac Charger
Philip Davis ,
Heart-failure patients may someday get a life-saving charge from technology developed by students at Rice University. A team of seniors designed and built a transcutaneous energy-transfer (TET) unit to power a minimally invasive ventricular assist device (VAD) being created by a Houston, Texas-based company. The VAD is a tiny pump inserted into the aorta through a catheter that helps increase blood flow and heal patients with heart failure.
Rice tCoil—Michael Torre, Erin Watson, Tyler Young, Trevor Mitcham, Hana Wang, and Alex Dobranich—made a complementary device that sits a centimeter under the skin and feeds power to the VAD. The challenge presented to the seniors, who were required to complete a capstone design project by Rice’s George R. Brown School of Engineering, was to charge the unit wirelessly.
"A lot of people need heart transplants, but there aren't enough hearts available," Young said. "One alternative is to have a heart pump implanted, but that carries risks. It's very invasive surgery, and afterward you have to have wire leads running out of your body" to a battery pack.
The portal through the skin to a power supply can become infected, he said. But the problem is avoidable by sending power to the VAD without wires. The students' prototype consists of a small coil and a battery that would be inserted one centimeter under the skin at the patient’s waist and wired to the VAD. The patient would also wear a belt-mounted external battery and coil to generate alternating magnetic fields and induce alternating current in the subcutaneous coil. The coils charge the battery, which can operate the pump for more than three hours.
"The patient can take the belt off for a short time, to take a shower, for instance," Young said. "The pump will work safely off the coils or on the internal battery alone, but obviously it's best when they're both working."
The team demonstrated tCoil at the Engineering Design Showcase that was part of Rice's recent UnConvention open house. The students put the internal and external coils on either side of a baggie containing lunchmeat to simulate power transfer through the skin. The internal unit was wired to a demonstration pump that clearly pushed red-colored water through a sleeve inside a tank.
The student project was in response to a request from Rice alum Michael Cuchiara, director of research and development at Procyrion, developer of the pump.