Peristaltic Pump Air Bubble Detection in Blood Processing

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Solution Overview

Problem

Current blood separation technologies, such as centrifuges, face challenges in detecting and preventing large air bubbles from entering the bloodstream during the separation and return of blood components, which can be painful or harmful to donors.

Innovation Solution

A centrifuge blood separation apparatus with a sensor structure in the outflow race of the return peristaltic pump, utilizing capacitive plates or sonic sensors to detect air bubbles, automatically alerts operators or stops the procedure if bubbles exceed a predetermined size or volume, ensuring donor safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a centrifuge is used to separate blood components, then blood components can be separated and returned to the donor, but air bubbles may be inadvertently introduced into the fluid which can be painful or harmful to the donor

Engineering Contradiction:
Improveblood component separation and returnVSAvoidair bubbles in returned blood
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The air bubble detection sensor is positioned in the outflow race of the return peristaltic pump to detect air bubbles before they enter the donor's bloodstream. The system performs preliminary detection and alerting, allowing operators to take corrective action before harmful bubbles reach the donor.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sensor structure acts as an intermediary between the blood processing system and the donor. It monitors the blood components in the return loop and provides warning signals when air bubbles are detected, serving as a protective intermediary that prevents direct harm to the donor.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a sensor is added to detect air bubbles in the return loop, then donor safety is improved, but device complexity increases

Engineering Contradiction:
Improvedonor safetyVSAvoidsensor structure in outflow race
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor structure is integrated into the existing peristaltic pump housing, utilizing the outflow race and exit slot already present in the pump assembly. This allows the air bubble detection function to be added without requiring a completely separate detection system, thereby reducing the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sensor structure utilizes the existing fluid flow through the outflow race and exit slot to detect air bubbles. The blood components themselves serve as the medium for detection, eliminating the need for separate complex detection mechanisms and reducing overall device complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If air bubble detection is implemented, then harmful bubbles can be detected and the procedure can be stopped, but measurement precision requirements increase for detecting small bubbles

Engineering Contradiction:
Improveair bubble detection accuracyVSAvoidminimum bubble size detection
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The sensor structure is designed to detect air bubbles based on changes in physical parameters such as density, compressibility, or acoustic properties. By monitoring these parameter changes in the blood flow, the system can reliably detect air bubbles of various sizes without requiring extremely high measurement precision for small bubbles.

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 monitors and prevents the introduction of harmful air bubbles into the bloodstream, enhancing the safety and comfort of the blood donation process by reliably detecting and responding to air bubbles in the return loop.

Implementation Method 1

Such a sensor comprises capacitive plates

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a tube of the tubing set together with fluid and any air bubbles contained therein form a dielectric for a capacitive sensor

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

at least one peristaltic pump comprising a housing with a cylindrical inner cavity with a floor and a U-shaped inner wall, at least one roller arm

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Implementation Method 4

The centrifuge rotates a blood separation vessel to separate components within the vessel or reservoir using centrifugal force

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 5

blood enters the separation vessel while it is rotating at a very rapid speed and centrifugal force stratifies the blood components

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP2389967B1Peristaltic pump and blood processing apparatus with air bubble detector
Publication Date: 2013.11.13 TERUMO BCT INC
  • EP2389967B1 patent drawingFigure 1
  • EP2389967B1 patent drawingFigure 2
  • EP2389967B1 patent drawingFigure 3

AI summary

A centrifuge for separating blood and blood components having a blood processing vessel mounted on a rotor of a centrifuge. A sensor in the outflow race of a return peristaltic pump detects air bubbles in the fluid within a return loop. The sensor may be a sonic sensor, a sonic pulse echo sensor, or capacitive plates. A pre-determined minimum bubble size or sizes or a cumulative volume may be selected, and the device operator may be warned only of the existence of bubbles that exceed a certain size or of a cumulative volume of bubbles, or the blood donation procedure may be stopped if a bubble exceeds a certain critical size or if a pre-determined volume of bubbles over a certain period or volume of fluid is exceeded.