TRANSCUTANEOUS ENERGY-TRANSFER SYSTEM PERFORMANCE EVALUATION

A transcutaneous energy transfer (TET) system has been developed to po wer implantable devices such as artificial hearts, defibrillators, and electrical stimulators. Transcutaneous coupling of power to these imp lanted devices vices remains a favorable alternative as percutaneous l ines are avoided in order to eliminate the potential of infection and allow patient mobility. In vitro, in vivo, ex vivo, and human cadaver studies of the electrohydraulic ventricular assist device TET have dem onstrated that power can be transmitted over a range of skin thickness es of 3-15 mm and can tolerate radial misalignments of up to 20 mm. Se nsitivity to coil separation and radial misalignment variations has be en addressed by the development of an autotuning TET. The system has o nly a 10% attenuation in secondary coil voltage when metallic objects are in contact with the primary coil. The system has demonstrated a po wer transfer efficiency of 60-80% for power demands from 5 to 70 W. Th e TET secondary coil will provide an output voltage of 10-25 V for cur rent demands from 0.5 to 4.0 A. TET chronic studies in porcine models have demonstrated no adverse effect to the tissue when up to 40 W of p ower can be delivered to an implanted load without the tissue-contacti ng surface of the coil exceeding 42 degrees C. In conclusion, the TET is a feasible alternative for tether-free power transmission.