Hemodynamic Parameter Estimation Using Vascular Tone
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Solution Overview
Problem
Existing methods for estimating hemodynamic parameters, such as cardiac output and stroke volume, are inaccurate due to the assumption that arterial flow in a single location represents total arterial flow, and they fail to account for variations in vascular tone across different arterial branches.
Innovation Solution
A controller is used to determine hemodynamic parameter estimates by combining arterial flow measurements with time difference measures (ΔT) between heart blood ejection events and pulse wave arrivals at different arterial paths, effectively integrating information about vascular tone variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blood flow is measured in a single arterial branch to estimate hemodynamic parameters, then the measurement process is simple and fast, but the estimation accuracy is insufficient due to flow rate variations and autoregulation differences across arterial branches
Solution Approach 1:
The patent divides the arterial system into multiple segments (central arterial path and peripheral arterial path) and measures blood flow in each segment separately. By segmenting the measurement locations, the system captures flow rate variations and autoregulation differences across different arterial branches, thereby improving hemodynamic parameter estimation accuracy while maintaining measurement efficiency through parallel processing of multiple locations
Solution Approach 2:
The patent adds a spatial dimension to the measurement system by incorporating multiple arterial paths (central and peripheral) instead of relying on a single measurement point. This dimensional expansion allows the system to account for regional differences in vascular tone and flow characteristics, transforming a one-point measurement into a multi-location assessment that improves accuracy without significantly increasing complexity
2Measurement precision
If multiple arterial paths are measured to account for vascular tone variations, then hemodynamic parameter estimation accuracy is improved, but the device complexity and measurement process increase
Solution Approach 1:
The patent employs a transfer function that serves multiple purposes: it processes blood flow measurements from different arterial paths, incorporates pulse arrival time data, and generates hemodynamic parameter estimates. This multi-functional approach allows the system to handle complex multi-location measurements without proportionally increasing device complexity, as the same computational framework processes all input data streams
Solution Approach 2:
The patent introduces a transfer function as an intermediary computational element that integrates measurements from multiple arterial paths and pulse arrival time data. This intermediary processing layer consolidates the complex multi-source data into unified hemodynamic parameter estimates, managing system complexity by providing a structured approach to data integration rather than requiring direct complex interactions between all measurement components
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 approach leads to more accurate estimates of central hemodynamic parameters, enabling improved clinical decision-making and medical interventions with better patient outcomes.
Implementation Method 1
obtain for each of a central arterial path and a peripheral arterial path a measure indicative of a time difference, ΔT, between a heart blood ejection event and arrival of a corresponding pulse wave at a pre-determined location along the respective arterial path
Implementation Method 2
receive an input indicative of an arterial flow measurement in at least one arterial path of the subject
Data Source
AI summary
An apparatus and method for estimating one or more hemodynamic parameters such as cardiac output or stroke volume. Embodiments are based on the concept of incorporating information about vascular tone into hemodynamic parameter estimation to improve accuracy. More particularly, embodiments use a measurement of a time duration for a blood pulse to travel from the heart along a certain length of an arterial path as a proxy measure for vascular tone, and incorporate this into hemodynamic parameter estimation. Embodiments are also based on incorporating vascular tone proxy measurements for multiple different arterial paths to take account of vascular tone variations between different portions of the circulatory system.