Active-Pulse Blood Analysis System for Motion-Compensated Oximetry
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Solution Overview
Problem
Conventional pulse oximetry systems fail to accurately measure arterial oxygen saturation during patient movement, low perfusion, and intense ambient light due to interference from venous blood flow and other environmental factors.
Innovation Solution
The active-pulse blood analysis system employs an optical sensor that illuminates a tissue site with multiple wavelengths, separating arterial and active pulse data to calculate arterial and venous oxygen saturation parameters. A decision logic module selects the appropriate oxygen saturation value based on motion and perfusion inputs, ensuring accurate measurements even under challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pulse oximetry measures blood oxygen saturation using optical absorption, then oxygen saturation can be determined, but measurement accuracy deteriorates during patient movement due to venous blood flow interference
Solution Approach 1:
The patent segments the blood flow signal into arterial and venous components by separating pulsatile (arterial) signals from non-pulsatile or slowly varying (venous) signals through frequency domain analysis. This allows independent measurement of arterial oxygen saturation without venous contamination.
Solution Approach 2:
The patent uses advanced signal processing that processes beyond the basic AC component to include analysis of the DC component and its variations. By analyzing both AC (pulsatile) and DC (non-pulsatile) components separately, the system can isolate arterial signals even when venous blood moves during patient motion.
2Reliability
If conventional pulse oximetry uses standard signal processing, then system complexity remains low, but measurement reliability deteriorates under low perfusion conditions
Solution Approach 1:
The patent introduces an intermediary processing stage that separates and independently analyzes AC and DC signal components. This intermediary step allows the system to extract arterial oxygen saturation information from the DC component when AC signals are weak due to low perfusion, improving reliability without requiring complex hardware modifications.
Solution Approach 2:
The patent performs preliminary separation of AC and DC components and their respective variations before final oxygen saturation calculation. This preliminary processing prepares the signals in advance, allowing the system to switch between different calculation methods based on signal quality, thereby improving reliability under varying perfusion conditions.
3Measurement precision
If conventional pulse oximetry processes both AC and DC components together, then processing is simple, but measurement accuracy deteriorates during patient motion
Solution Approach 1:
The patent segments the total signal into AC (pulsatile) and DC (non-pulsatile) components, and further segments their variations. By analyzing AC variations for arterial oxygen saturation and DC variations separately, the system achieves accurate measurements during patient motion while maintaining manageable processing complexity through structured separation.
Solution Approach 2:
The patent applies different processing levels to AC and DC components - using AC variations for standard measurements and DC variations when AC signals are compromised. This partial processing approach maintains simplicity for normal conditions while providing enhanced accuracy capabilities when needed.
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 system effectively reports true arterial oxygen saturation and pulse rate during patient movement, low perfusion, and intense ambient light, providing reliable measurements that conventional pulse oximetry systems cannot achieve.
Implementation Method 1
an optical sensor that illuminates a tissue site with multiple wavelengths of optical radiation and that outputs sensor signals responsive to the optical radiation after attenuation by pulsatile blood flow
Data Source
AI summary
An active-pulse blood analysis system has an optical sensor that illuminates a tissue site with multiple wavelengths of optical radiation and outputs sensor signals responsive to the optical radiation after attenuation by pulsatile blood flow within the tissue site. A monitor communicates with the sensor signals and is responsive to arterial pulses within a first bandwidth and active pulses within a second bandwidth so as to generate arterial pulse ratios and active pulse ratios according to the wavelengths. An arterial calibration curve relates the arterial pulse ratios to a first arterial oxygen saturation value and an active pulse calibration curve relates the active pulse ratios to a second arterial oxygen saturation value. Decision logic outputs one of the first and second arterial oxygen saturation values based upon perfusion and signal quality.