Blood Pulsation Spectral Analysis for Short-Duration Fluid Responsiveness
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Solution Overview
Problem
Existing fluid responsiveness parameters are unreliable and inaccurate in unstable heart or respiration situations, particularly when short measurement durations are necessary, limiting their clinical utility in determining hemodynamic parameters.
Innovation Solution
A system and method for determining fluid responsiveness parameters using respiratory and heart rates, combined with blood pulsation signals, employing spectral analysis to identify multiple signals up to the heart rate and its harmonics, and applying filters to enhance signal properties, allowing for efficient and robust parameter determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluid responsiveness parameters (PPV, SPV) are used in stable heart and respiration situations, then measurement accuracy is improved, but clinical applicability deteriorates due to limited use cases
Solution Approach 1:
The patent applies dynamics by making the measurement system adaptable to changing physiological conditions. The method dynamically adjusts to unstable heart rates and respiration patterns by using real-time detection of ectopic beats and arrhythmias, and by modifying the analysis approach based on detected conditions, thereby maintaining accuracy across varying clinical scenarios rather than requiring stable conditions
Solution Approach 2:
The patent changes the measurement parameters and analysis methods based on detected physiological conditions. When instability is detected, the system modifies which parameters are measured and how they are analyzed, transitioning from conventional PPV/SPV methods to alternative approaches that remain valid under unstable conditions, thus expanding clinical applicability without sacrificing accuracy
2Reliability
If measurement duration is extended to improve reliability, then parameter accuracy is improved, but measurement time increases which is not feasible for short duration maneuvers
Solution Approach 1:
The patent applies preliminary action by performing quality assessments and reliability checks during the measurement process itself rather than requiring extended measurement times. The system continuously monitors signal quality and detects artifacts in real-time, allowing it to identify reliable measurements quickly without needing to extend the measurement duration, thus maintaining reliability while minimizing time loss
Solution Approach 2:
The patent enables rushing through the measurement process by using methods that can quickly identify reliable data points. The system can detect sufficient information within a few respiration cycles by focusing on key parameters and using real-time analysis to skip unnecessary measurement time, thereby achieving reliable results for short duration maneuvers like passive leg raise
3Loss of information
If spectral analysis is extended to higher frequencies up to heart rate and harmonics, then signal information is improved, but computational complexity increases
Solution Approach 1:
The patent extracts only the essential frequency components needed for accurate fluid responsiveness measurement. Rather than analyzing the entire frequency spectrum up to heart rate and all harmonics, the method identifies and extracts the specific frequency ranges containing the most relevant information about respiratory variations, thereby maintaining signal information completeness while reducing computational complexity by eliminating unnecessary frequency analysis
Data Source
AI summary
A system (100) for determining a fluid responsiveness parameter, FRP, for a patient is presented, wherein the determined fluid responsiveness parameter is a systolic pressure variation (SPV) or a pulse pressure variation (PPV) that comprises units (101, 102, 103) for providing a respiratory rate, a heart rate and a measured blood pulsation signal indicative of a series of blood pulses of a patient. The system further comprises a unit (104) for determining, a first processed signal (env_up) based on the blood pulsation signal, wherein the first processed signal is indicative of an upper envelope of the blood pulsation signal, and a second processed signal (env_down) based on the blood pulsation signal, wherein the second processed signal is indicative of a lower envelope of the blood pulsation signal, and a unit (105) for determining the FRP by a) identifying, based on the first and second processed signals, first FRP determination signals (baseline_up, baseline_down) corresponding to the first and second processed signals in a spectral range up to the respiratory rate, and second FRP determination signals (ripple_up, ripple_down) corresponding to the first and second processed signals at the respiratory rate and any of its harmonics up to the heart rate, and b) determining the FRP based on the first and the second FRP determination signals.