Physiological Information Processing With Vascular Distensibility Correction
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Solution Overview
Problem
Existing methods for calculating cardiac output fail to consider the vascular distensibility parameter, leading to discrepancies between invasive measurements and calculations based on heart rate and pulse wave transit time, necessitating improved calculation accuracy.
Innovation Solution
A method and apparatus that acquire electrocardiogram, pulse wave, and blood pressure data to measure heart rate and pulse wave transit time, calculate vascular distensibility parameters like systemic vascular resistance, and correct cardiac output calculations using these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cardiac output is calculated using only heart rate and pulse wave transit time, then the calculation process is simple, but the calculation accuracy is insufficient and discrepancies arise with invasive measurements
Solution Approach 1:
The patent introduces vascular distensibility parameters (systemic vascular resistance, arterial elastic modulus, dynamic arterial elastic modulus, or pulse-amplitude index) as additional variables to the cardiac output calculation. By changing the parameters considered in the calculation model from just heart rate and pulse wave transit time to include vascular distensibility parameters, the calculation accuracy is improved while maintaining a manageable computational complexity through established mathematical relationships.
2Measurement precision
If vascular distensibility parameters are measured and used for correction, then the calculation accuracy is improved, but the measurement and calculation process becomes more complex
Solution Approach 1:
The patent uses pulse wave transit time as an intermediary parameter that can be easily measured non-invasively and is correlated with vascular distensibility. By measuring pulse wave transit time and using it to derive or estimate vascular distensibility parameters, the system avoids direct complex measurements of vascular properties while still capturing their effect on cardiac output calculation.
Solution Approach 2:
The patent implements a feedback mechanism where the calculated vascular distensibility parameters are used to correct the initial cardiac output calculation. The system continuously monitors heart rate, pulse wave transit time, and blood pressure, recalculates vascular distensibility parameters, and applies corrections to the cardiac output value, creating a closed-loop system that improves accuracy through iterative refinement.
Data Source
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AI summary
A physiological information processing method includes: acquiring electrocardiogram data of a subject; acquiring pulse wave data of the subject; measuring the heart rate based on the electrocardiogram data; measuring the pulse wave transit time based on the electrocardiogram data and the pulse wave data; calculating a cardiac output based on the pulse wave transit time and heart rate which have been measured; calculating the systemic vascular resistance; and correcting the calculated cardiac output based on the systemic vascular resistance.