Cardiotomy Reservoir Undulating Guide Surface
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Solution Overview
Problem
Conventional cardiotomy and venous blood reservoirs are suboptimal for pediatric applications due to issues with flow discontinuities, turbulence, and trauma caused by splashing at low flow rates, and inefficient air handling, particularly in neonates and infants.
Innovation Solution
A cardiotomy and venous blood reservoir design featuring a venous sub-assembly with a flared downtube and a bowl that promotes laminar flow, combined with a cardiotomy sub-assembly with an undulating guide surface to minimize splashing, and a defoamer system that only contacts foamed portions of the blood, enhancing air handling and reducing blood trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional cardiotomy and venous reservoirs are used, then air bubble removal and particulate filtration are achieved, but flow discontinuities and turbulence occur at low flow rates causing blood trauma
Solution Approach 1:
The patent employs curved surfaces throughout the reservoir design, including a domed top surface, a rounded bottom surface, and curved transition regions between chambers. These curved geometries eliminate sharp corners and edges that would cause flow separation and turbulence, particularly at low flow rates. The smooth continuous curves guide blood flow gently through the reservoir, preventing trauma to blood cells while maintaining effective air bubble removal and particulate filtration capabilities.
Solution Approach 2:
The patent modifies flow parameters by incorporating flow straightening elements and transition zones that gradually change flow velocity and direction. The design includes extended transition regions where flow parameters (velocity, pressure, direction) are gradually adjusted rather than abruptly changed, preventing turbulence and flow discontinuities that cause blood trauma while maintaining effective separation and filtration functions.
2Object-affected harmful factors
If conventional reservoir designs are used, then air handling is achieved, but inefficient air removal occurs in pediatric applications with low blood volumes
Solution Approach 1:
The patent divides the reservoir into distinct functional chambers: a venous chamber for receiving and initial processing of venous blood, a cardiotomy chamber for processing cardiotomy suction blood, and a main reservoir chamber for combining and storing the processed blood. This segmentation allows each chamber to be optimized for its specific function, with the venous and cardiotomy chambers equipped with dedicated air venting pathways that efficiently remove air bubbles even when blood volumes are low, as encountered in pediatric applications.
Solution Approach 2:
The patent incorporates intermediate transition chambers and flow distribution elements that act as mediators between the venous/cardiotomy chambers and the main reservoir chamber. These intermediate structures provide extended air-liquid contact surfaces and gradual mixing zones that enhance air bubble coalescence and removal efficiency, particularly effective when dealing with the low blood volumes characteristic of pediatric perfusion circuits.
3Object-affected harmful factors
If defoamers are continuously contacted with blood flow, then foam elimination is achieved, but unnecessary blood contact with defoamer occurs
Solution Approach 1:
The patent positions defoamers such that they are contacted by blood flow only periodically or intermittently, specifically when foam is present and rises to the defoamer location. The design allows normal blood flow to bypass the defoamer or contact it minimally, while foam bubbles that rise to the surface trigger defoamer activation. This periodic contact pattern eliminates unnecessary blood-defoamer interaction while maintaining effective foam elimination capability.
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 design achieves smooth, laminar flow and minimizes trauma at low flow rates, effectively removing air bubbles and reducing the formation of foam, improving the handling and processing of blood in pediatric perfusion circuits.
Implementation Method 1
The downstream region extends from the upstream region and terminates at a downstream end located within the venous chamber. In this regard, a diameter of the lumen increases along at least the downstream region to the downstream end. The bowl is disposed within the venous chamber and forms a floor surface facing the downstream end for receiving venous blood flow from the lumen.
Implementation Method 2
the inner post forms a guide surface defined by a leading segment and a trailing segment for directing cardiotomy liquid flow from the dish aperture to the cardiotomy chamber. The leading segment is received within the central aperture and has a diameter that is less than a diameter of the central aperture. The trailing segment extends downwardly from the leading segment and forms an undulating curvature.
Implementation Method 3
a cardiotomy and venous blood reservoir design featuring a venous sub-assembly with a flared downtube and a bowl that promotes laminar flow, combined with a cardiotomy sub-assembly with an undulating guide surface to minimize splashing, and a defoamer system that only contacts foamed portions of the blood, enhancing air handling and reducing blood trauma.
Data Source
AI summary
A cardiotomy and venous blood reservoir, including a housing assembly, a venous inlet port, a venous sub-assembly, a cardiotomy inlet port, and a cardiotomy sub-assembly. The housing forms a chamber. The venous sub-assembly includes a downtube and a bowl. A diameter of the downtube lumen increases to a downstream end. The bowl forms a floor surface for receiving flow from the lumen. The cardiotomy sub-assembly includes a dish and an inner post. The dish defines an aperture. The inner post extends from the dish and forms a guide surface received within the central aperture and forming an undulating curvature increasing to a diameter greater than the diameter of the central aperture. Cardiotomy liquid drops from the dish fall on to the undulating, closely positioned guide surface with minimal splashing.