Adaptive Filter Setting for Blood Pressure Signal Artefact Rejection
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Solution Overview
Problem
Non-invasive blood pressure monitors and other physiological parameter measurements are susceptible to artefacts such as tremor, shivering, and environmental vibrations, which affect the accuracy of measurements, particularly when the useful information is carried in a fundamental frequency and its amplitude.
Innovation Solution
A filter configuration system that uses patient category and sensor or transducer information to select appropriate filters, such as linear time-invariant (LTI) or adaptive filters, to minimize the impact of artefacts by setting filter properties like corner frequencies, filter order, and constraints based on expected heart rate ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed filter configuration is used for blood pressure measurement, then the device complexity is reduced, but measurement precision deteriorates due to artefacts like tremor and shivering affecting the pressure signal
Solution Approach 1:
The filter configuration is made dynamic by automatically adjusting filter parameters based on detected signal characteristics. The system analyzes the pressure signal to identify artefact frequencies and adapts the filter settings in real-time, transforming a static filter into a dynamic one that responds to changing measurement conditions, thereby improving measurement precision without requiring complex manual configuration
Solution Approach 2:
The system performs self-configuration by automatically detecting artefact frequencies from the pressure signal and adjusting its own filter parameters without external intervention. The monitoring device independently analyzes its input signal, identifies interference patterns, and modifies its filter settings accordingly, enabling the device to serve itself in optimizing measurement accuracy
2Measurement precision
If signal filtering is applied to remove artefacts, then measurement precision improves, but loss of useful information may occur if filter parameters are not optimally selected
Solution Approach 1:
The system employs feedback mechanisms where the filtered signal is continuously monitored and the filter parameters are adjusted based on the quality of the output. The system analyzes the relationship between input and output signals, detects when useful information is being attenuated, and provides feedback to modify filter settings, creating a closed-loop system that prevents information loss while maintaining artefact rejection
Solution Approach 2:
The system dynamically changes filter parameters such as cutoff frequencies and filter orders based on the detected characteristics of the physiological signal and artefacts. By adapting parameters like the corner frequency of the low-pass filter to match the expected heart rate range and artefact frequencies, the system optimizes the balance between removing harmful artefacts and preserving useful physiological information
3Measurement precision
If patient-specific filter settings are implemented, then measurement precision improves, but ease of operation deteriorates due to additional configuration steps
Solution Approach 1:
The system automatically performs patient-specific filter configuration by analyzing the individual's physiological signal characteristics without requiring manual input. The device independently determines appropriate filter parameters based on detected heart rate, artefact frequencies, and signal quality metrics, eliminating the need for operators to manually configure patient-specific settings while still achieving individualized measurement accuracy
Solution Approach 2:
The system performs preliminary analysis of the physiological signal to pre-configure optimal filter settings before the actual measurement is completed. By proactively identifying patient-specific signal characteristics and pre-adjusting filter parameters during the measurement process, the system eliminates the need for post-measurement configuration steps, maintaining ease of operation while achieving personalized accuracy
Data Source
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AI summary
The present invention relates to a setting device (13) for a physiological parameter monitoring device (10, 20, 30) configured to measure a physiological parameter of a patient, e.g. the blood pressure. The setting device use patient category information indicating the patient category of the patient and/or sensor or transducer information indicating one or more of type, size, shape, attachment location or intended patient population of a sensor (100) or transducer (200, 300), estimates an expected range of the patient's heart rate from the obtained patient category information and/or the obtained sensor or transducer information, generates one or more settings of a filter (11) based on the expected range of the patient's heart rate and configures the filter (11) for filtering a sensor signal measured by the physiological parameter monitoring device (10, 20, 30) or the sensor (100) based on the generated settings.