Apheresis Blood Processing Flow Rate Modulation
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Solution Overview
Problem
Conventional apheresis blood processing methods experience high incidence of blood vessel infiltration due to rapid changes in access blood vessel pressure, leading to patient discomfort, potential health risks, and processing inefficiencies.
Innovation Solution
The method involves systematically varying blood flow rates over time during blood processing, with controlled removal and return flow rates derived from the total blood volume, and using recirculation to maintain quasi-steady state flow conditions, thereby minimizing pressure changes and reducing infiltration risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional apheresis blood processing methods are used with constant flow rates, then blood components can be collected efficiently, but rapid changes in access blood vessel pressure occur causing high incidence of blood vessel infiltration
Solution Approach 1:
The patent applies dynamics by systematically varying the return flow rate over time during the blood return phase, transitioning from a constant flow rate to a time-dependent variable flow rate. This allows the system to adapt to the blood vessel's pressure dynamics, reducing rapid pressure changes that cause infiltration while maintaining efficient blood component collection. The return flow rate is modulated to match the compliance characteristics of the access blood vessel.
Solution Approach 2:
The patent changes the flow rate parameter from a constant value to a time-varying function during blood return. By systematically varying the return flow rate according to the blood vessel's pressure-response characteristics, the system optimizes both safety (reducing infiltration) and efficiency (maintaining collection productivity). The flow rate profile is adjusted based on vessel compliance measurements.
2Loss of time
If rapid blood removal and return is performed to minimize processing time, then productivity increases, but pressure changes in access blood vessel accelerate causing infiltration
Solution Approach 1:
The patent employs periodic action by using cyclic draw and return phases with systematically varying flow rates. During each return phase, the flow rate is modulated in a controlled manner to accommodate vessel pressure dynamics. This periodic modulation allows efficient blood component collection over multiple cycles while preventing infiltration during each individual cycle by adapting to the vessel's elastic response.
Solution Approach 2:
The patent applies beforehand cushioning by pre-characterizing the compliance of the access blood vessel and using this information to design an optimal return flow rate profile. The system measures or estimates vessel compliance beforehand and uses this data to shape the return flow rate curve, cushioning against rapid pressure changes before they can cause infiltration. This preparatory characterization enables safe and efficient processing.
3Ease of operation
If high flow rates are used during blood return to maintain donor comfort, then donor comfort improves, but pressure changes still cause blood vessel infiltration
Solution Approach 1:
The patent implements feedback by using the measured or estimated compliance of the access blood vessel to dynamically adjust the return flow rate profile. The system continuously adapts the flow rate based on the vessel's pressure-response characteristics, ensuring that high flow rates are used only when the vessel can accommodate them without infiltration. This feedback mechanism reconciles donor comfort with infiltration prevention.
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
This approach significantly reduces the incidence of blood vessel infiltration, enhances donor or patient comfort, and increases the efficiency and purity of blood component collection, with a 30% reduction in infiltration incidence compared to conventional methods.
Implementation Method 1
Separation of blood into its components may be performed continuously during collection or may be performed subsequent to collection in batches, particularly with respect to the processing of whole blood samples. Both conventional blood collection and apheresis systems typically employ differential centrifugation methods for separating blood into its various blood components.
Implementation Method 2
Rotation of the separation chamber creates a centrifugal force directed along rotating axes of separation oriented perpendicular to the central rotation axis of the centrifuge. The centrifugal field generated upon rotation separates particles suspended in the blood sample into discrete fractions accordingly to density.
Implementation Method 3
using recirculation to maintain quasi-steady state flow conditions
Data Source
AI summary
Methods, devices and device components are presented for blood processing. Particularly, methods, devices and device components are presented for separating blood into blood components and collecting one or more separated blood components, which reduce the incidence of blood vessel infiltration and enhance donor comfort. In one aspect, the invention provides blood processing methods having a return flow rate which decreases systematically during a return time. In another aspect, the invention provides blood processing methods having a removal flow rate, return flow rate or both which are derived from a subject's total blood volume. In another aspect, the present invention provides blood processing methods wherein the fraction by volume of removed blood corresponding to collected components is selected to optimize blood processing efficiency and enhance the purities of collected blood components.