Blood Flow Slope Index for Circulation State Evaluation
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Solution Overview
Problem
Conventional methods for evaluating blood circulation state, such as skin perfusion pressure (SPP) and transcutaneous partial pressure of oxygen (TcPO2), are cumbersome for patients and fail to clearly distinguish between different symptomatic states, necessitating a new index value that can accurately indicate blood circulation status.
Innovation Solution
A method and device that measure blood flow rate over time, calculate the slope of this change, and use it as an index value to evaluate blood circulation state, capable of clearly differentiating between healthy and deteriorated circulation states, even within underlying tissue layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods like SPP or TcPO2 are used to evaluate blood circulation state, then the evaluation can be performed on mass tissue including muscle and thick blood vessels, but the procedure imposes a heavy burden on patients requiring cuff pressurization or tissue warming
Solution Approach 1:
The invention extracts only the essential measurement function from complex conventional systems. Instead of using cuff pressurization devices or warming apparatus, the patent employs a simple light-emitting and light-receiving unit that directly measures blood flow rate through optical detection, eliminating unnecessary mechanical and thermal components while preserving measurement capability
Solution Approach 2:
The patent replaces mechanical pressurization systems (cuffs) and thermal systems (warming devices) with an optical measurement system. The light-emitting unit irradiates the measurement site and the light-receiving unit detects blood flow rate changes through optical absorption and scattering properties of blood, substituting complex mechanical-thermal procedures with a non-invasive optical method
2Reliability
If conventional index values like SPP or TcPO2 are used, then blood circulation state can be evaluated, but these values fail to clearly distinguish between different symptomatic states such as ischemic and non-ischemic conditions
Solution Approach 1:
The invention applies periodic stimulus (warming) to the measurement site and measures blood flow rate changes over time. By analyzing the temporal pattern of blood flow response to periodic thermal stimulus, the system captures dynamic information about vascular reactivity and blood circulation state, enabling clear distinction between ischemic and non-ischemic conditions through the characteristics of the response curve
Solution Approach 2:
The patent transitions from static measurements (single-point SPP or TcPO2 values) to dynamic measurements by continuously monitoring blood flow rate changes over time in response to warming stimulus. The slope calculation unit computes the rate of change of blood flow rate, providing dynamic information about vascular response that clearly distinguishes between different symptomatic states
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
The slope of blood flow rate serves as a reliable index value, accurately indicating blood circulation state, allowing for precise evaluation and distinguishing between healthy and deteriorated states, with clinical trials confirming its reliability equivalent to existing methods like TcPO2 and SPP.
Implementation Method 1
a light emitting unit configured to irradiate a measurement site with light; a light receiving unit configured to receive the light
Implementation Method 2
measuring a blood flow rate of a biological tissue based on the light received by the light receiving unit
Data Source
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AI summary
In order to obtain a new index value clearly indicating a state of blood circulation, the present invention is characterized by comprising: performing multiple measurements of the blood flow rate in a biological tissue over time; calculating the slope of change over time in the measured blood flow rate; and displaying the value of the calculated slope.