In-Vivo Blood Pressure Sensor Calibration via Gas Reference
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Solution Overview
Problem
In-vivo blood pressure sensors, particularly those associated with in-vivo balloons, face challenges in accurate calibration due to manufacturing inconsistencies and environmental stress, leading to drift in sensor performance, which existing calibration methods fail to address effectively, especially since re-zeroing and compensating for scale factor variability are impractical during in-vivo use.
Innovation Solution
The solution involves calibrating in-vivo blood pressure sensors using dynamic blood pressure waveforms during procedures like IAB therapy, utilizing simultaneous readings from fiber optic sensors and shuttle gas pressure sensors to correct for drift and scale factor errors, allowing for continuous calibration without operator intervention by maintaining the balloon in a partially inflated state and processing data with algorithms that assume the shuttle gas pressure sensor as a reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used for in-vivo blood pressure sensors, then initial sensor accuracy can be achieved, but sensor drift and scale factor variability occur during in-vivo use leading to measurement inaccuracy
Solution Approach 1:
The patent implements a feedback mechanism where the fiber optic sensor continuously monitors blood pressure and compares readings with a reference value (initial calibration or known physiological range). When drift is detected, the system automatically adjusts the scale factor and zero offset to maintain measurement accuracy throughout the in-vivo usage period.
Solution Approach 2:
The fiber optic sensor performs self-calibration by utilizing its own output signal and comparing it against reference criteria. The sensor system automatically detects its own drift and corrects it without requiring external calibration equipment or operator intervention, enabling continuous accurate measurement during in-vivo use.
2Measurement precision
If re-zeroing and scale factor compensation are performed during in-vivo use, then sensor drift can be corrected, but operator intervention and additional calibration procedures are required increasing system complexity
Solution Approach 1:
The system performs automatic self-calibration using the fiber optic sensor's own signal and embedded algorithms. The microprocessor continuously analyzes the sensor output, detects drift conditions, and applies corrections automatically without requiring external calibration equipment or operator intervention, thereby maintaining accuracy while minimizing system complexity.
Solution Approach 2:
The patent changes the operational parameters of the sensor system by continuously adjusting the scale factor and zero offset based on real-time signal analysis. This dynamic parameter adjustment allows the sensor to adapt to drift conditions automatically, maintaining measurement precision without requiring complex manual calibration procedures.
3Measurement precision
If frequent recalibration is performed to maintain accuracy, then measurement precision can be maintained, but procedure time and operational complexity increase
Solution Approach 1:
The fiber optic sensor performs continuous calibration throughout the entire in-vivo measurement period rather than requiring discrete recalibration events. The system continuously monitors its own performance and applies real-time corrections, eliminating downtime and ensuring uninterrupted accurate measurement without requiring periodic procedure interruptions for recalibration.
Solution Approach 2:
The sensor system performs automatic self-calibration using embedded algorithms that continuously analyze the output signal and adjust calibration parameters in real-time. This eliminates the need for operator-initiated recalibration procedures, reducing both calibration time and operational complexity while maintaining continuous measurement accuracy throughout the procedure.
Data Source
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AI summary
A method for performing an in-vivo calibration of a blood pressure sensor (40) that is associated with a balloon (10) of an in-vivo balloon system, the sensor and balloon being associated such that the sensor is in-vivo when the balloon is in-vivo. The balloon is inflated so that a gas pressure in the balloon system is indicative of a patient's blood pressure. The patient's blood pressure is monitored through two channels, the gas pressure and the sensor. The blood pressure measurements obtained by monitoring the gas pressure are used as reference, or "true," blood pressure measurements to determine a mathematical relationship between blood pressure measurements obtained through the sensor and the reference blood pressure measurements. In this manner, future blood pressure measurements obtained through the sensor can be modified according to the mathematical relationship to generate calibrated blood pressure measurements.