A multichannel implantable telemetry system for flow, pressure, and ECG measurements

Area of Science:

• Biomedical Engineering
• Implantable Medical Devices
• Telemetry Systems

Background:

• Chronic implantation of telemetry systems has advanced from single to multichannel devices over 15 years.
• Measuring parameters like blood flow and dimension has been challenging due to high power demands.
• Existing systems struggle with power-intensive measurements, limiting chronic in-vivo monitoring.

Purpose of the Study:

• To design a multiplex telemetry system for simultaneous measurement of up to eight physiological parameters.
• To overcome power limitations in chronic implantable devices, specifically for blood flow measurement.
• To develop a system capable of long-term, in-vivo monitoring of multiple vital signs.

Main Methods:

• Developed a multiplex system capable of measuring eight individual parameters, including blood flow using an electromagnetic transducer.
• Engineered a low-power electromagnetic flow measurement technique requiring only a few hundred milliwatts.
• Utilized two rechargeable NiCad batteries, recharged transcutaneously via inductive coupling at 250 kHz.
• Configured units to measure electrocardiogram (ECG), two pressures, temperature, and ascending aortic flow.

Main Results:

• Successfully designed and constructed a multichannel telemetry system for chronic implantation.
• Achieved simultaneous measurement of multiple parameters, including blood flow, with reduced power consumption.
• Demonstrated effective transcutaneous inductive recharging of implanted batteries.
• Current configurations monitor ECG, dual pressures, temperature, and aortic flow.

Conclusions:

• The developed multiplex telemetry system addresses the limitations of previous devices, enabling chronic measurement of previously difficult parameters like blood flow.
• The low-power design and inductive recharging offer a viable solution for long-term, in-vivo physiological monitoring.
• This technology has significant potential for advancing chronic disease management and physiological research.