Introduction - This work focuses on developing transcutaneous energy transfer systems (TETS) to power wirelessly the next generation of artificial heart pumps, particularly left-ventricular assist devices (LVADs). This work aims to understand the blood perfusion factors to mitigate thermal damage of the subcutaneous tissue. For this, we emulated the heating effects due to power losses in both continuous and pulsed heating waveform protocols.
Methods - A Radiofrequency Power Loss Emulator (RFPLE) was developed to conduct a study on the cutaneous blood circulation cooling effects in the porcine model at various power loss levels, independently of the wireless power supply coupling method being used and their associated inefficiency, thus, enabling analysis and modelling of the skin tissue thermal profile data under a wide range of power loss levels while on-pulse-transmission (50W-700W), on-pulse durations (30ms-480ms) and blood perfused cooling off-time durations (5s-120s). In-silico modelling enabled knowledge-mined characterisation of sub-cutaneous blood circulation cooling factors. Both conventional continuous and pulsed transmission protocols were implemented to assess the heating coefficient from the temperature data of the subcutaneous heating element, for the living-model and in the cadaver-model of 3 porcine cases.
Results - The estimated heating coefficient in the living-model measurement, both in pulsed and continuous power transmission heating losses, varied from 1.56x(10-3)±(10-6)°C/s and 7.71x(10-4)±(10-6)°C/s, respectively. The heating coefficient under no-blood-circulation (cadaver) conditions, was at least an order of magnitude higher and varied from 2.22x(10-3)±(10-6)°C/s to 3.14x(10-3)±(10-6)°C/s. Moreover, the heating loss in the continuous transmission is about 2°C higher, or more, than the pulsed transmission. Histological analyses of in-vivo and cadaver models studies confirmed tissue damage occurring in the cadaver measurements due to no blood perfusion.
Conclusion - We have characterised blood flow cooling factors and proposed methods for harnessing this important capacity using a novel power-loss emulation system for designing safe high-power TETS with mitigated dermal tissue heating effects.
|Title of host publication||Institute of Electrical and Electronics Engineers (IEEE)|
|Subtitle of host publication||IEEE Engineering in Medicine and Biology Society|
|Publication status||Accepted/In press - 12 Jun 2022|
|Event||Computing in Cardiology 2022 - Tampere, Tampere, Finland|
Duration: 4 Sept 2022 → 7 Sept 2022
|Name||Computing in Cardiology, 2022 Conference paper|
- Transcutaneous Energy Transfer Systems
- Radiofrequency Power Loss Emulator
- Wireless p[ower supply to LVAD
- Dermal Blood Flow Thermoregulation
- Skin heating
- Subcutaneous blood flow cooling factors