Optical Sensor Calibration for Plasma Hemoglobin Monitoring
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Solution Overview
Problem
Current blood processing systems face challenges in accurately monitoring and preventing the return of excess free plasma hemoglobin to donors or patients, often triggering unnecessary alarms due to transient elevated concentrations.
Innovation Solution
A fluid separation system equipped with an optical sensor assembly and controller that monitors the concentration of free plasma hemoglobin in the plasma outlet line, calculates the total amount based on the output, and uses a pre-programmed reference equation for calibration to ensure accurate measurements, reducing false alarms and preventing excessive hemoglobin return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical sensor assembly monitors free plasma hemoglobin concentration continuously, then the ability to detect excessive hemoglobin is improved, but the number of false alarms increases due to transient elevated concentrations
Solution Approach 1:
The system performs a calibration test before normal monitoring to establish baseline parameters. This preliminary action prepares the system by determining expected optical properties of plasma without hemoglobin interference, enabling later differentiation between true abnormalities and transient variations
Solution Approach 2:
The system continuously compares real-time optical sensor readings against the calibrated baseline parameters and adjusts alarm thresholds dynamically. This feedback mechanism allows the system to distinguish between transient elevated concentrations and genuine excessive hemoglobin levels, reducing false alarms while maintaining detection accuracy
2Measurement precision
If calibration parameters are established through experimental determination, then measurement precision is improved, but device complexity increases due to additional calibration procedures
Solution Approach 1:
The system performs self-calibration by automatically establishing baseline parameters during an initial calibration test without requiring manual intervention or external reference materials. The controller autonomously determines calibration parameters from the optical sensor data, simplifying the calibration process while maintaining measurement precision
Solution Approach 2:
The calibration test is performed as a preliminary one-time procedure during system initialization or maintenance periods. By completing the complex calibration work in advance, the system establishes accurate measurement parameters without requiring ongoing complex calibration procedures during normal operation
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 calculates and monitors free plasma hemoglobin concentrations, minimizing unnecessary alarms and ensuring safe levels are maintained, thereby preventing over-infusion of free plasma hemoglobin.
Implementation Method 1
an optical sensor assembly configured to monitor the contents of the plasma outlet line and produce an output indicative of the concentration of free plasma hemoglobin in the plasma outlet line
Implementation Method 2
Whole blood is typically separated into its constituents (e.g., red cells, platelets, and plasma) through centrifugation
Data Source
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AI summary
A system is provided for separating a plasma-containing fluid into separated plasma and a concentrated fluid. The system cooperates with a fluid flow circuit including a fluid separation chamber and a plasma outlet line associated therewith for removing separated plasma from the fluid separation chamber. The system includes an optical sensor assembly to monitor the contents of the plasma outlet line and produce an output indicative of the concentration of free plasma hemoglobin in the plasma outlet line. A controller of the system calculates the amount of free plasma hemoglobin in at least a portion of the concentrated fluid based at least in part on the output of the optical sensor assembly. The controller may periodically calibrate the optical sensor assembly by determining an instrument-specific correlation between optic output and free hemoglobin concentration and comparing it to experimentally determined data to ensure continued reliability of the optical sensor assembly.