Segmented Blood Pump Bearings for Thrombosis and Hemolysis
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Solution Overview
Problem
Blood pumps face challenges with blood clots and hemolysis due to stagnation in bearing areas, requiring improved fluid flow and pressure-volume characteristics to minimize thrombosis and hemolysis risks.
Innovation Solution
A modular bearing system incorporating unique sleeve and cone bearing designs with modified geometries to enhance blood flow and lubrication, including features like thrust rings and segmented cone bearings to promote full washing of bearing surfaces and reduce thrombosis risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sleeve bearings are used in blood pumps, then radial confinement is provided, but blood stagnation occurs leading to thrombosis
Solution Approach 1:
The sleeve bearing is divided into multiple circumferential segments with gaps between them, allowing blood to flow through the bearing structure rather than stagnate, thereby reducing thrombosis risk while maintaining radial confinement
Solution Approach 2:
The bearing structure incorporates regions with different properties: solid segments provide radial confinement while gaps provide flow pathways, creating local variations in function within the same component
2Reliability
If conventional cone bearings are used for axial and radial confinement, then bearing stability is improved, but blood flow obstruction increases
Solution Approach 1:
The cone bearing is segmented into multiple circumferential sections with interstitial gaps, enabling blood to flow through the bearing assembly while the conical geometry maintains axial and radial confinement stability
Solution Approach 2:
Blood flow is redirected from a two-dimensional path around the bearing to a three-dimensional path that flows through the bearing structure itself via the gaps between segments
3Reliability
If bearing surfaces are designed for optimal contact, then pressure-velocity characteristics improve, but hemolysis risk increases due to high shear forces
Solution Approach 1:
A lubricating fluid layer is maintained between bearing surfaces to mediate the interaction, reducing direct contact and shear forces on blood cells while preserving pressure-velocity characteristics through proper lubrication management
Solution Approach 2:
The bearing design modifies geometric parameters such as surface curvature and gap dimensions to optimize the balance between pressure-velocity characteristics and shear force reduction, minimizing hemolysis risk
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 modular bearing system effectively reduces thrombosis and hemolysis risks by enhancing fluid flow and lubrication, maintaining favorable pressure-volume characteristics, and minimizing forces that lead to adverse blood interactions within the pump.
Implementation Method 1
a drive bearing between the drive magnet and the impeller assembly
Implementation Method 2
enhancing fluid flow to the bearing regions, enhancing fluid flow from the bearing regions, creating lubricating fluid layers in the bearing regions
Data Source
AI summary
A blood flow assist system can include an impeller assembly including an impeller shaft and an impeller on the impeller shaft, a primary flow pathway disposed along an exterior surface of the impeller. The system can include a rotor assembly at a proximal portion of the impeller shaft. A secondary flow pathway can be disposed along a lumen of the impeller shaft. During operation of the blood flow assist system, blood can be pumped proximally along the primary flow pathway and the secondary flow pathway. The system can include a sleeve bearing distal the impeller. The system can include a drive unit having a distal end disposed distal a proximal end of the second impeller. The drive unit comprising a drive magnet and a drive bearing between the drive magnet and the impeller assembly.