Adaptive Intrathoracic Impedance Threshold for Pulmonary Edema Detection
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Solution Overview
Problem
Heart failure patients are at risk of developing pulmonary edema due to increased left-side cardiac dysfunction, which requires effective monitoring techniques to detect the onset and degree of the condition, as existing methods are inadequate.
Innovation Solution
An implantable device is used to monitor intrathoracic impedance by determining a threshold based on factors such as left atrial pressure, NYHA class, and echocardiographic information, allowing for comparison of impedance changes over time to trigger alarms or interventions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed threshold is used for intrathoracic impedance monitoring, then the monitoring method is simple, but it cannot accurately detect pulmonary edema in all patients due to individual variations in cardiac function and disease stage
Solution Approach 1:
The patent implements dynamic threshold adjustment by continuously adapting the alarm threshold based on real-time intrathoracic impedance measurements and patient-specific parameters. The system transitions from a static fixed threshold to a dynamic adaptive threshold that changes according to the patient's physiological state, improving detection accuracy while maintaining system feasibility through automated calculations
Solution Approach 2:
The system changes the monitoring parameter from a single fixed threshold value to multiple adjustable parameters including baseline impedance, rate of change thresholds, and time-weighted averages. These parameters are customized based on patient-specific factors such as cardiac function, disease stage, and response to treatment, allowing precise detection without requiring complex manual configuration
2Measurement precision
If patient-specific parameters such as left atrial pressure and NYHA class are incorporated into threshold determination, then detection accuracy improves, but the complexity of determining appropriate thresholds increases
Solution Approach 1:
The system performs preliminary assessment during device implantation and initial programming by collecting patient-specific parameters such as left atrial pressure, NYHA class, and echocardiographic data. These parameters are used to pre-calculate personalized baseline thresholds before clinical use, eliminating the need for complex real-time adjustments while maintaining high detection accuracy
Solution Approach 2:
The monitoring system automatically uses the patient's own physiological data and clinical parameters to self-determine appropriate thresholds without requiring ongoing manual intervention. The system self-adjusts thresholds based on measured impedance trends and patient response to therapy, reducing complexity by making the threshold determination process autonomous rather than requiring continuous clinician input
3Loss of time
If monitoring considers multiple phases of pulmonary edema development, then early detection capability improves, but the complexity of monitoring criteria increases
Solution Approach 1:
The patent segments the pulmonary edema development process into distinct phases (early interstitial edema, progressive edema, and severe edema) with different impedance change characteristics. Each phase has simplified monitoring criteria tailored to its specific physiological changes, allowing early detection without requiring a single complex criterion that must cover all disease stages
Solution Approach 2:
The system applies different monitoring strategies and thresholds for different time periods corresponding to disease phases. During early phases, more sensitive thresholds detect subtle impedance changes, while during progressive phases, thresholds adapt to larger changes. This periodic adjustment of monitoring criteria enables timely detection across all phases without maintaining permanently complex monitoring rules
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 method enables early detection and monitoring of pulmonary edema, providing timely interventions and improving patient outcomes by accounting for various phases and mechanisms associated with the condition.
Implementation Method 1
determining a threshold for use in intrathoracic impedance monitoring
Data Source
AI summary
An exemplary method includes providing information (e.g., a left atrial pressure, a NYHA class, echocardiographic information, etc.), based at least in part on the information, determining a weight and, based at least in part on the weight, determining a threshold for use in intrathoracic impedance monitoring. Such an exemplary method may include comparing an intrathoracic impedance to the threshold, comparing an intrathoracic impedance change to the threshold, or comparing a product of intrathoracic impedance and time to the threshold. Various exemplary methods, devices, systems, etc., are disclosed.