Validation of a totally implantable blood flow, blood pressure and temperature biotelemetry system

Abstract

The EndoGear totally implantable multichannel biotelemetry system was validated using standard bench‐top instruments. Although this biotelemetry system has already been used in a variety of animal models, it had not been validated over a wider range of heart rates, blood flow velocities, blood pressures and temperatures.Positive displacement pulsatile waveforms were generated using a bellows‐type pump and reference blood flow velocity was measured with a bench‐top Doppler flowmeter (Indus Instruments, 20MHz Doppler flowmeter module), while reference blood pressure was measured with a solid‐state blood pressure catheter (Millar Instruments, model SPR524). Similarly, reference temperature was measured with a calibrated temperature sensor. The pump rate, stroke volume and pressure‐chamber pressure were adjusted to simulate various physiological levels and were recorded on a computer. Temperature was varied separately, in a temperature controlled water bath, and the transmitted temperature data were recorded.The results show that the EndoGear implant is capable of accurately measure flow velocity, pressure and rate waveforms in a large physiological range. This makes it useful in studies where blood flow velocities are in the range of 5‐100 cm/s, blood pressures are in the range of 0 to 300 mmHg, heart rates are up to 250 bpm and temperatures are in the range of 0 to 50°C. The size and weight of this implant allow it to be used in animals with body weights = 2 kg.This research was supported by the Swedish Science Research Council Grants B‐DR 09856‐304 and 621‐2005‐2588