Lead Impedance Monitoring for Polysomnography Signal Integrity
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Solution Overview
Problem
Polysomnography systems face issues with lead detachment during sleep studies, leading to signal loss and disruptions, as existing technologies do not effectively ensure optimal lead integrity and automatic switching to redundant leads.
Innovation Solution
A method and apparatus that use multiple leads with an AC current source and switching mechanism to determine impedance, automatically selecting an optimal pair of leads by injecting AC current and switching to alternative pairs if impedance thresholds are not met, ensuring continuous data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead detachment is not detected and addressed, then the study can continue without interruption, but signal quality and data reliability deteriorate
Solution Approach 1:
The system performs preliminary impedance checks on all leads before beginning the polysomnography study and continuously monitors impedance during the study. This preliminary and ongoing detection allows the system to identify lead detachment issues before they compromise signal quality or require study interruption.
Solution Approach 2:
The system automatically detects lead detachment through impedance monitoring and self-corrects by switching to backup leads without requiring clinician intervention. This self-service capability maintains signal quality and continues data acquisition without study interruption.
2Reliability
If clinician manually checks and reattaches detached leads, then signal quality is maintained, but study disruption and time loss increase
Solution Approach 1:
The system automatically monitors lead impedance and detects detachment events, then autonomously switches to pre-configured backup leads. This eliminates the need for manual clinician intervention to reattach leads, maintaining signal integrity while preserving study efficiency and avoiding patient awakening.
Solution Approach 2:
Backup leads are pre-configured and ready before the study begins. When detachment is detected, the system immediately switches to these pre-positioned backup leads, maintaining continuous monitoring without requiring manual reattachment procedures that disrupt the study.
3Reliability
If impedance monitoring is performed continuously, then lead detachment is detected promptly, but system complexity and power consumption increase
Solution Approach 1:
The same differential amplifier and signal processing circuitry used for physiological signal acquisition is also utilized for impedance monitoring. By making the monitoring system multi-functional, the patent avoids adding separate dedicated monitoring hardware, thereby detecting lead detachment promptly without significantly increasing device complexity.
4Adaptability or versatility
If multiple backup leads are used, then automatic switching capability is improved, but device complexity and initial setup increase
Solution Approach 1:
The lead configuration is segmented into primary leads and backup leads, with each serving a specific function. This segmentation allows the system to have targeted redundancy only where needed, improving automatic switching capability while avoiding the complexity of complete system redundancy.
Solution Approach 2:
The switching mechanism and impedance monitoring system serve dual purposes: they monitor all leads for impedance changes and simultaneously manage switching between primary and backup leads. This multi-functionality reduces the need for separate dedicated switching hardware, thereby improving adaptability without proportionally increasing device complexity.
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 solution ensures continuous and reliable data acquisition by automatically switching to optimal leads, minimizing disruptions and maintaining signal integrity during polysomnography studies, thereby improving the quality of sleep testing.
Implementation Method 1
determine an impedance across the currently selected pair of leads based on the AC voltage
Data Source
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Figure 2
AI summary
An physiological data acquisition apparatus includes three or more leads, at leastone AC current source, a switching mechanism structured to selectively couple the current source to selected lead pairs to inject an AC current across the selected lead pairs which produces an AC voltage across the selected lead pair, and a processing device. The processing device is structured to (i) determine an impedance across the current selected lead pair based on the AC voltage, (ii) determine whether the impedance is less than a predetermined threshold, (iii)if the impedance is less than the predetermined impedance threshold cause the current selected lead pair to be used for generating physiological parameter data, and (iv) if the impedance is notless than the threshold cause the switching mechanism tocouple the at least one AC current source to a new selected pair ofthe leads.