Simultaneous Multi-Channel Impedance Measurement in Implantable Devices
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Solution Overview
Problem
Existing implantable medical devices face challenges in obtaining multiple impedance vectors simultaneously due to time-consuming sequential measurements and significant delays when switching between vectors, which limits their effectiveness in monitoring cardiac and respiratory conditions.
Innovation Solution
The implementation of a system with synchronized multiplexers and separate signal processing channels allows for the simultaneous measurement of multiple impedance vectors, reducing the time required to obtain data and minimizing delays between measurements by using a current pulse generator and sensing circuit with multiplexers to connect electrodes and process signals efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sequential impedance measurement method is used, then device complexity is reduced, but measurement time increases significantly
Solution Approach 1:
The patent divides the impedance measurement system into multiple independent signal processing channels, each capable of processing a different impedance vector simultaneously. This segmentation allows parallel measurement of multiple vectors without requiring a single complex sequential processing path, thereby reducing measurement time while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The patent transitions from sequential time-based measurement to simultaneous parallel measurement by adding channel dimensionality. Instead of measuring vectors one after another in time sequence, the system measures multiple vectors across multiple channels at the same time, effectively moving from a 1D time sequence to a 2D channel-time matrix measurement approach.
2Device complexity
If multiple impedance vectors are measured sequentially, then signal processing is simplified, but monitoring effectiveness deteriorates
Solution Approach 1:
The patent segments the signal processing into separate independent channels, each handling one impedance vector. This allows each channel to maintain simple, dedicated processing logic while the overall system achieves comprehensive monitoring through parallel operation of multiple segmented channels, thus preserving monitoring effectiveness without excessive processing complexity.
Solution Approach 2:
The patent creates a universal measurement framework where multiple impedance vectors are processed through a standardized multi-channel architecture. Each channel performs the same basic impedance measurement function but on different vectors simultaneously, allowing the system to maintain simple universal processing logic while achieving effective multi-parameter monitoring.
3Measurement precision
If impedance measurements are taken over extended periods to reduce noise, then measurement precision improves, but time consumption increases
Solution Approach 1:
The patent enables continuous simultaneous measurement of multiple impedance vectors across multiple channels, allowing the system to collect sufficient data for noise reduction in parallel rather than sequentially. This continuous parallel operation maintains high measurement precision through adequate sampling while avoiding the time penalty of sequential collection, as all channels accumulate data concurrently.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the time needed to collect impedance measurements, enabling more robust and consistent data collection, improving the monitoring of cardiac and respiratory functions, and allowing for real-time evaluation of physiological changes.
Implementation Method 1
a current pulse generator configured to deliver current pulses through a selected one of the plurality of different subsets of the implantable electrodes
Implementation Method 2
a sensing circuit configured to sense a signal indicative of an impedance associated with a selected one of the plurality of different subsets of the implantable electrodes
Data Source
AI summary
An implantable system includes terminals, a pulse generator, a sensing circuit, separate signal processing channels, and first, second and third multiplexers. The terminals are connected to electrodes via conductors of leads. Different subsets of the electrodes are used to define different electrical pulse delivery vectors, and different subsets of the electrodes are used to define different sensing vectors. The pulse generator produces electrical pulses, and the sensing circuit senses a signal indicative of an impedance associated with a selected sensing vector. The first multiplexer selectively connects outputs of the pulse generator to a selected one of the different electrical pulse delivery vectors at a time. The second multiplexer selectively connect inputs of the sensing circuit to a selected one of the different sensing vectors at a time. The third multiplexer selectively connects an output of the sensing circuit to one of the plurality of separate signal processing channels at a time.