Blood Processing Controller for Target Hematocrit and Volume
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Solution Overview
Problem
Current blood processing systems face challenges in achieving target fractions of patient cells remaining, hematocrit levels, and fluid volume changes during therapeutic red blood cell exchange procedures, particularly in maintaining isovolemic conditions without volume changes.
Innovation Solution
A blood processing system with a controller that adjusts flow rates and fluid communication paths to achieve target fractions of patient cells, hematocrit levels, and fluid volume changes by determining specific operating parameters and flow rates, including the use of replacement fluids like saline or albumin, to ensure precise control during red blood cell exchange procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If red blood cells are removed from the patient during therapeutic exchange procedure, then the fraction of diseased cells is reduced, but the patient's fluid volume changes
Solution Approach 1:
The system dynamically adjusts flow rates (QWB, QP, QRF) as controllable parameters to simultaneously achieve target FCR, hematocrit, and fluid volume change. The controller modifies these parameters in real-time based on procedural conditions to maintain isovolemic exchange
Solution Approach 2:
The system uses feedback from monitored procedural conditions to continuously adjust the flow rates of whole blood withdrawal, plasma return, and replacement fluid infusion. This closed-loop control ensures that both cell fraction and fluid volume targets are achieved simultaneously
2Quantity of substance
If replacement fluids are infused to maintain fluid volume, then isovolemic conditions are maintained, but precise control of hematocrit levels becomes more complex
Solution Approach 1:
The controller performs multiple functions: calculating flow rates, monitoring procedural conditions, adjusting parameters in real-time, and coordinating multiple flow paths. This multi-functional control system manages the complexity of simultaneous hematocrit and volume control
Solution Approach 2:
The system dynamically adjusts flow rates during the procedure rather than using fixed rates. The controller continuously modifies QWB, QP, and QRF based on changing procedural conditions to maintain precise control over both hematocrit and fluid volume
3Manufacturing precision
If multiple flow rates are adjusted simultaneously, then target hematocrit and fluid volume are achieved, but the system complexity increases
Solution Approach 1:
The control system is segmented into distinct controllable components: whole blood withdrawal flow rate (QWB), plasma return flow rate (QP), and replacement fluid infusion flow rate (QRF). Each flow path is independently controlled and monitored, simplifying the management of multiple parameters
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 achieves target end hematocrit, fraction of cells remaining, and fluid volume changes, enabling precise control and maintaining isovolemic conditions, which is crucial for treating conditions like sickle cell anemia by simultaneously processing and returning fluids to maintain acceptable blood viscosity and volume.
Implementation Method 1
an inlet flowpath having a pump operable at a prescribed rate QWB to convey whole blood from a patient
Implementation Method 2
a blood separation device for separating whole blood into a red blood cell component and a plasma component
Implementation Method 3
a first outlet flowpath including a pump operable at a prescribed flow rate QP to convey separated plasma from the separation device
Implementation Method 4
a third flowpath including a pump operable at a prescribed flow rate QRF is provided to convey replacement red blood cells to the patient
Data Source
AI summary
Systems and methods for performing a therapeutic red blood cell exchange procedure are disclosed. In one aspect, a system includes a first flow path for flowing whole blood from a patient. A separator communicates with the first flow path for separating at least red blood cells from plasma. Second and third flow paths communicate with the separator for respectively flowing the separated plasma and red blood cells from the separator. A flow controller is associated with the flow paths to control fluid communication between the flow paths. The controller is configured to perform the procedure to achieve a target fraction of patient cells remaining, target hematocrit, and a target patient fluid volume change at the completion of the procedure based on data input by the operator.