Blood Container Empty Detection via Weight and Flow Rate

Solution Overview

Problem

Automated blood processing systems face challenges in accurately determining when a whole blood container is empty, leading to potential air entry and damage to red blood cells or leukoreduction failures due to over-emptying, and under-emptying results in suboptimal product recovery.

Innovation Solution

A method and system that utilize a combination of measured gross weight and calculated fluid flow rate from a weigh scale to determine when a whole blood container is empty, stopping the flow when both conditions are met to prevent air entry and ensure complete utilization of the blood.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the system continues pumping whole blood from the container until the weigh scale indicates empty, then complete blood utilization is achieved, but air may enter the fluid circuit causing hemolysis or leukoreduction failure

Engineering Contradiction:

Improveblood utilizationVSAvoidprocess reliability

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The system performs preliminary action by stopping the pumping process before the container is completely empty. The controller monitors the weigh scale readings and stops pumping when the weight reaches a predetermined threshold that indicates a small amount of blood remains in the container, preventing air entry while maximizing blood utilization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the weigh scale to continuously monitor the container weight during the pumping process. The controller receives real-time weight information and adjusts the pumping operation accordingly, stopping the process when the weight indicates the container is nearly empty, thus balancing complete utilization with prevention of air entry.

Inventive Principle:

Principle #23Feedback

2Reliability

If the system stops pumping when the weigh scale indicates empty, then air entry is prevented, but incomplete blood utilization occurs

Engineering Contradiction:

Improveprocess reliabilityVSAvoidblood utilization

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The system performs preliminary action by stopping the pumping process before the container is completely empty. The controller monitors the weigh scale readings and stops pumping when the weight reaches a predetermined threshold that indicates a small amount of blood remains in the container, preventing air entry while maximizing blood utilization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the weigh scale to continuously monitor the container weight during the pumping process. The controller receives real-time weight information and adjusts the pumping operation accordingly, stopping the process when the weight indicates the container is nearly empty, thus balancing complete utilization with prevention of air entry.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If a fixed pump rate is used throughout the process, then pumping simplicity is maintained, but accurate empty detection becomes difficult as flow rate changes during separation

Engineering Contradiction:

Improvepumping simplicityVSAvoidempty detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system uses feedback from the weigh scale to continuously monitor the container weight during the pumping process. The controller receives real-time weight information and adjusts the pumping operation accordingly, stopping the process when the weight indicates the container is nearly empty, thus balancing complete utilization with prevention of air entry.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the parameter being monitored from flow rate to container weight. By using the weigh scale to measure the container weight rather than relying on flow rate measurements, the system achieves accurate empty detection despite variations in pump rate and flow conditions during the separation process.

Inventive Principle:

Principle #35Parameter changes

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

Effectively prevents air entry into the separation system, reduces hemolysis and leukoreduction failures, and ensures that red blood cell and plasma products meet quality standards by accurately detecting the empty state of the whole blood container.

Implementation Method 1

determining a target weight for an empty whole blood container; determining a target flow rate of whole blood from the container of whole blood indicative of a near empty whole blood container; flowing whole blood from the container of whole blood to the separator; determining a current weight of the container of whole blood with the weigh scale

Methodology Applied

Scientific EffectWeight measurement:

Data Source

PatentEP3753587B1Systems and methods for detecting an empty WB container

Publication Date: 2024.08.07 FENWAL INC

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AI summary

A system and method are provided for separating previously-collected whole blood into a red blood cell fraction and a plasma fraction by which the container of previously-collected whole blood is determined to be empty based on using the combination of the measured gross weight of the container and a calculated fluid flow rate from the container, based on weigh scale feedback. Upon detection of the empty container, flow from the container is stopped.