Wearable Defibrillator Impedance Control via Fluid Deployment
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Solution Overview
Problem
Wearable cardiac defibrillators face challenges with gelled electrodes that can dry out and irritate the skin, increasing impedance and discomfort during electrical shocks.
Innovation Solution
Incorporating an energy storage module and conductive fluid reservoirs with controlled fluid release mechanisms to decrease impedance and discomfort, with sensors to deliver the stored charge when impedance meets a discharge condition, and optional use of different fluids for varying treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gelled electrodes are used in wearable cardiac defibrillators, then electrical contact with skin is improved, but the gel dries out and irritates the skin, increasing impedance and discomfort
Solution Approach 1:
The system performs preliminary impedance sensing and conductive fluid deployment before delivering the defibrillation shock. The fluid is deployed in advance to prepare the electrode-skin interface, ensuring low impedance conditions are established prior to shock delivery, thereby preventing discomfort and skin irritation while maintaining reliable electrical contact
Solution Approach 2:
The system continuously senses impedance between electrodes and uses this feedback to control fluid deployment. When impedance exceeds a threshold or discharge conditions are met, the system automatically deploys conductive fluid to reduce impedance, creating a closed-loop control system that maintains optimal electrical contact without excessive gel application
Solution Approach 3:
The system automatically monitors impedance and deploys fluid as needed without requiring manual intervention. The wearable defibrillator self-regulates the electrode-skin interface conditions by sensing impedance changes and activating fluid deployment mechanisms to maintain optimal contact, eliminating the need for pre-application of large amounts of gel
2Reliability
If conductive fluid is deployed to decrease impedance, then electrical shock delivery is improved, but patient discomfort from irritation can occur if fluid is not controlled
Solution Approach 1:
Impedance sensing provides continuous feedback to control fluid deployment. The system only deploys conductive fluid when impedance measurements indicate it is necessary, and monitors the resulting impedance change to determine when sufficient fluid has been applied, preventing over-application that would cause skin irritation while ensuring adequate fluid for effective shock delivery
Solution Approach 2:
The system changes the impedance parameter by controlling fluid deployment timing and amount. By adjusting when and how much fluid is deployed based on real-time impedance measurements, the system optimizes the electrical properties of the electrode-skin interface to achieve low impedance for effective shock delivery without excessive fluid that would cause discomfort
3Object-affected harmful factors
If fluid is released in multiple doses with pauses, then patient comfort is improved, but treatment time is increased
Solution Approach 1:
The system implements periodic fluid deployment with intervening pauses between doses. Fluid is released in controlled intervals, allowing the system to assess impedance changes and patient response between deployments. This periodic approach distributes fluid application over time, preventing sudden excessive application that would cause skin irritation while ultimately achieving the necessary impedance reduction for shock delivery
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
Minimizes patient discomfort and irritation by reducing impedance at the electrode-skin interface, ensuring effective and comfortable electrical shock delivery.
Implementation Method 1
an impedance measurement circuit to sense an impedance between the two electrodes
Implementation Method 2
One or more reservoirs can store one or more conductive fluids. Respective fluid deploying mechanisms can be configured to cause the fluids to be released from one or more of the reservoirs, which decreases the impedance at the patient location
Data Source
AI summary
In embodiments, a wearable cardiac defibrillator system includes an energy storage module configured to store a charge. Two electrodes can be configured to be applied to respective locations of a patient. One or more reservoirs can store one or more conductive fluids. Respective fluid deploying mechanisms can be configured to cause the fluids to be released from one or more of the reservoirs, which decreases the impedance at the patient location, and decreases discomfort for the patient. In some embodiments an impedance is sensed between the two electrodes, and the stored charge is delivered when the sensed impedance meets a discharge condition. In some embodiments, different fluids are released for different patient treatments. In some embodiments, fluid release is controlled to be in at least two doses, with an intervening pause.