Plethysmographic Cardiac Output Shift Detection
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Solution Overview
Problem
Current methods for monitoring cardiac output are invasive, costly, and require high computing capacity, limiting their accessibility and ease of use for continuous patient monitoring.
Innovation Solution
A computer-implemented method using plethysmographic signals, processed from light reflected or transmitted through the body, to determine shifts in cardiac output by analyzing slopes, magnitude of signal fall, and areas between specific time intervals, without the need for high computing power, facilitating a portable and user-friendly device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods like pulmonary artery catheter (PAC) are used to monitor cardiac output, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent replaces the mechanical/invasive PAC system with a photoplethysmographic optical system. The method uses light absorption changes in blood vessels to detect cardiac output shifts, substituting mechanical catheter-based measurement with non-invasive optical detection. This resolves the contradiction by maintaining measurement capability while eliminating the complexity and invasiveness of the mechanical system.
Solution Approach 2:
The patent introduces photoplethysmographic signals as an intermediary medium to indirectly measure cardiac output. Instead of directly measuring blood flow through invasive catheters, the system uses light interaction with blood volume changes in peripheral vessels as a mediator to infer cardiac output shifts. This intermediary approach enables non-invasive measurement with acceptable precision.
2Measurement precision
If high computing capacity methods are used to analyze pressure signals, then measurement precision is improved, but ease of operation and accessibility deteriorate
Solution Approach 1:
The patent extracts and utilizes specific characteristic features from photoplethysmographic signals (such as pulse wave morphology, amplitude variations, and timing parameters) that are directly related to cardiac output. By focusing on these extracted key features rather than performing comprehensive high-computing analysis of entire pressure waveforms, the system achieves accurate cardiac output determination with lower computational requirements, improving device accessibility.
3Measurement precision
If invasive pressure measurement methods are used, then measurement precision is improved, but object-affected harmful factors increase
Solution Approach 1:
The patent replaces invasive mechanical pressure measurement (requiring arterial catheter insertion) with non-invasive photoplethysmographic detection. The optical system measures blood volume changes in peripheral vessels through light absorption, substituting the harmful invasive mechanical approach with a safe optical method that provides sufficient precision for cardiac output monitoring without causing patient harm.
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
Enables accurate and accessible monitoring of cardiac output shifts, reducing costs and complexity, making it suitable for home care and reducing hospital admissions.
Implementation Method 1
A plethysmographic signal, also called PS, refers to the intensity of light reflected and/or transmitted by a user's body
Implementation Method 2
the value of the plethysmographic signal will drop significantly since the volume of blood that accumulates in said part thus hinders the transmission and reflection of light
Data Source
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AI summary
The invention relates to a method, device and system for determining a shift in cardiac output from a first plethysmographic signal in a first span of time in which at least one first period of time is included during which an output pressure measurement has been applied to the user that is higher than venous pressure and lower than systolic pressure, and a second plethysmographic signal in a second span of time, some time after the first span of time, in which at least one second period of time is included during which an output pressure measurement has been applied to the user that is higher than venous pressure and lower than systolic pressure.