Wearable Cardioverter Defibrillator Sensor Switching
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Solution Overview
Problem
Existing wearable cardioverter defibrillators (WCDs) are uncomfortable for patients, leading to low compliance due to messy and uncomfortable electrodes, resulting in limited wear time, which can compromise patient safety.
Innovation Solution
The use of non-electrode sensors such as photoplethysmographic (PPG) and accelerometer sensors to detect changes in health parameters, activating electrodes only when necessary, and employing self-deploying gel for therapeutic shocks, allowing for more comfortable and extended wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrode-based monitoring is used continuously, then cardiac arrhythmia detection capability is improved, but patient comfort deteriorates and wear time is reduced
Solution Approach 1:
The system uses non-invasive sensors for continuous monitoring and only activates electrodes periodically when arrhythmia is detected, rather than maintaining continuous electrode contact. This allows the device to switch between non-contact and contact modes based on patient condition
Solution Approach 2:
The invention extracts the continuous monitoring function from the electrode system and assigns it to non-invasive sensors (accelerometers, PPG sensors). The electrodes are removed from continuous use and reserved only for therapeutic intervention, eliminating the discomfort of continuous electrode wear
2Measurement precision
If electrodes are kept in constant contact with skin, then ECG signal quality is improved, but skin irritation and discomfort increase
Solution Approach 1:
The system performs preliminary detection using non-invasive sensors to identify potential arrhythmia conditions before activating electrodes. This preliminary action allows the system to prepare for ECG monitoring only when clinically necessary
Solution Approach 2:
Non-invasive sensors act as intermediaries between the patient and the electrode system. These sensors detect physiological parameters continuously without skin contact, serving as a bridge that eliminates direct electrode-skin contact during routine monitoring
3Ease of operation
If non-invasive sensors are used for continuous monitoring, then patient comfort is improved, but detection reliability may be reduced
Solution Approach 1:
The system uses feedback from non-invasive sensor data to trigger electrode activation. When sensors detect abnormal physiological patterns, the system responds by deploying electrodes for confirmatory ECG monitoring, creating a closed-loop feedback mechanism that maintains reliability
Solution Approach 2:
The monitoring system dynamically adjusts its invasiveness based on patient condition. It transitions from non-invasive continuous monitoring to invasive electrode-based monitoring only when arrhythmia is suspected, making the system adaptive to patient needs
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 increases patient compliance by enabling longer wear times and improved detection of potential cardiac arrhythmias, reducing discomfort and enhancing safety through comfortable and reliable monitoring and intervention.
Implementation Method 1
the at least one non-invasive physiologic sensor comprises one or more of a photoplethysmographic (PPG) sensor
Implementation Method 2
the accelerometer sensor is configured to monitor the change in health parameter as a function of respiration and a lack of breathing
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A wearable cardioverter defibrillator (WCD) (10) and method (60) comprise a set of electrodes (12) for placement on a subject (14), a mechanism for electrically engaging (16) the set of electrodes to the subject's skin, and at least one non-invasive physiologic sensor (18, 20) configured for placement on the subject. A controller (24) monitors an output of the non-invasive physiologic sensor (18, 20) for detecting a change in a health parameter of the subject being indicative of one or more of a change in subject condition that may be a precursor to potential cardiac arrhythmia or a simultaneously occurring cardiac arrhythmia. Responsive to detecting the change, the controller (24) activates an alarm (26) for requesting a response from the subject (14) within a predetermined time. Responsive to receiving the subject's response within the predetermined time, the controller (24) inhibits the mechanism (16) from electrically engaging the set of electrodes (12) to the subject's skin. Responsive to not receiving the subject's response, the controller (24) initiates the mechanism (16) for electrically engaging the set of electrodes (12) to the subject's skin.