Oxygenator Bubble Removal via Filter and Flow Deceleration

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Solution Overview

Problem

Existing oxygenators with hollow fiber membranes are not effectively designed to remove bubbles from blood, leading to bubble discharge downstream, necessitating additional arterial filters.

Innovation Solution

Incorporating a filter member positioned near the blood outlet port and a passage enlargement to decelerate blood flow, preventing bubbles from being carried out of the oxygenator, and using a gas outlet hollow fiber membrane layer to manage bubble removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a hollow fiber membrane bundle is designed to efficiently effect gas exchange, then gas exchange performance is improved, but bubble removal capability deteriorates

Engineering Contradiction:
Improvegas exchange performanceVSAvoidbubble removal capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention divides the oxygenator into functionally distinct segments: a hollow fiber membrane bundle for gas exchange and a separate filter member for bubble removal. This segmentation allows each component to be optimized for its specific function without compromising the other, resolving the contradiction between gas exchange efficiency and bubble removal capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter member acts as an intermediary component positioned between the hollow fiber membrane bundle and the blood outlet port. It specifically targets and removes bubbles from the blood without interfering with the gas exchange function of the hollow fiber membranes, thus resolving the contradiction by introducing a dedicated bubble removal mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If blood flow velocity is high, then gas exchange efficiency is improved, but bubble removal by filter member deteriorates

Engineering Contradiction:
Improvegas exchange efficiencyVSAvoidbubble removal effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The passage enlargement is positioned upstream of the filter member to preliminarily decelerate blood flow before it reaches the filtering stage. This preliminary action reduces the kinetic energy of the blood flow, enabling the filter member to effectively trap bubbles that would otherwise be carried away by high-velocity flow

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The passage enlargement creates a localized region of reduced flow velocity specifically at the inlet of the filter member, while maintaining higher flow velocities in other regions of the oxygenator for efficient gas exchange. This local modification of flow characteristics allows simultaneous optimization of both gas exchange efficiency and bubble removal effectiveness

Inventive Principle:
Principle #3Local quality

3Reliability

If a filter member is added to remove bubbles, then bubble removal capability is improved, but device complexity increases

Engineering Contradiction:
Improvebubble removal capabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The filter member is integrated with the housing and positioned in close proximity to the hollow fiber membrane bundle, merging the bubble removal function with the existing gas exchange structure. This integration approach adds minimal complexity while achieving effective bubble removal, as the filter member utilizes the existing blood flow path and housing space

Inventive Principle:
Principle #5Merging (Combining)

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 removes bubbles from blood, reducing the need for additional filters in the arterial line and enhancing gas exchange performance.

Implementation Method 1

hollow fiber membranes configured to subject the blood introduced into the housing to gas exchange

Methodology Applied
Scientific EffectGas exchange: Diffusion

Implementation Method 2

a passage enlargement is provided in a vicinity of an end of the blood outlet port closer to the housing and possessing an increased passage cross-sectional area so that blood which has passed through the filter member toward the blood outlet port is decelerated in the passage enlargement

Methodology Applied
Scientific EffectFlow deceleration: Bernoulli Effect

Implementation Method 3

a filter member is positioned at a side of the hollow fiber membrane bundle closer to the blood outlet port and is constructed to catch bubbles in the blood which has been subjected to the gas exchange

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2305332B1Oxygenator
Publication Date: 2018.08.08 TERUMO KK
  • EP2305332B1 patent drawingFigure 1
  • EP2305332B1 patent drawingFigure 2
  • EP2305332B1 patent drawingFigure 3

AI summary

An oxygenator (1) which helps avoid bubbles in the blood from being discharged through the blood outlet port of the oxygenator includes a housing (2), a hollow fiber membrane bundle (3) in the housing and formed by a multiplicity of hollow fiber membranes serving for gas exchange, gas-inlet and gas-outlet ports (26,28) communicating with gas passages of the hollow fiber membranes, and a blood-inlet and blood-outlet ports (51,28). A filter member (41) is provided on a side closer to the blood outlet port of the hollow fiber membrane bundle and serves to catch bubbles in blood. The blood outlet port projects from the housing and a passage enlargement (281) is provided in a vicinity of the end of the blood outlet port closer to the housing and having an increased passage cross-sectional area. The blood passed the filter member is allowed to reach the blood outlet port by being decelerated in the passage enlargement.