Pneumatic Ventricular Assist Device Blood Flow Optimization
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Solution Overview
Problem
Existing pneumatic ventricular assist devices face issues with blood flow stagnation and turbulence, leading to hemolytic effects, intravascular coagulation, and thrombosis risks due to uniform or larger inlet channel diameters compared to outlet channels, and non-uniform connector designs.
Innovation Solution
A pneumatic ventricular assist device with a spherical cap having an air and blood chamber separated by a membrane, featuring inlet and outlet channels with differently sized valve seats and uniformly convergent connectors, along with a two-part nut for secure cannula connection, optimizing blood flow and reducing turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diameter of the seat for the valve in the inlet channel is made larger than or equal to the diameter of the seat for the valve in the outlet channel, then the blood flow can be maintained, but areas of stagnation and turbulent flow increase leading to hemolytic effects and thrombosis risks
Solution Approach 1:
The patent applies local quality by creating different seat diameters for inlet and outlet channels, with the inlet channel having a smaller seat diameter than the outlet channel. This localized dimensional differentiation optimizes blood flow patterns in specific regions, reducing stagnation and turbulence while maintaining overall blood flow stability and reducing thrombosis risks.
Solution Approach 2:
The patent implements asymmetry by making the seat diameter in the inlet channel smaller than the seat diameter in the outlet channel, breaking the conventional symmetric or inverse symmetric design. This asymmetric configuration optimizes blood flow dynamics by reducing turbulent shear stress and areas of stagnation, thereby minimizing hemolytic effects and thrombosis while maintaining reliable blood flow.
2Ease of manufacture
If the inside channel of the connector is non-uniform with narrowing towards the second end, then the connector can be manufactured, but blood flow stagnation and turbulence occur increasing thrombosis risk
Solution Approach 1:
The patent applies local quality by making the inside channel of the connector uniformly convergent along its full working length, with consistent angular orientation. This localized geometric optimization ensures uniform blood flow distribution throughout the connector, preventing stagnation and turbulence that would otherwise occur in non-uniform designs, thereby reducing thrombosis risk while maintaining manufacturability.
3Object-affected harmful factors
If the connector inside channel is uniformly convergent, then blood flow stagnation is reduced, but the connection security may be compromised
Solution Approach 1:
The patent applies segmentation by dividing the connector into distinct functional sections: a uniformly convergent inside channel for optimized blood flow, and a separate coupling mechanism with external stop and two-part nut for secure connection. This segmentation allows each component to be optimized independently - the channel for blood flow dynamics and the coupling for connection security - resolving the contradiction between flow optimization and connection reliability.
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 solution reduces areas of low blood flow speed and turbulent shear stress, minimizing hemolytic and thrombotic risks while ensuring a secure and easy-to-assemble connection, enhancing blood flow dynamics and reducing the risk of coagulation.
Implementation Method 1
The pneumatic part of the spherical cap is connected to a generator making alternate pneumatic wave which stimulates alternate movement of the membrane located between the pneumatic part of the spherical cap and the blood chamber thereof
Implementation Method 2
The alternate movement of the membrane results in the blood flowing through the device
Implementation Method 3
circular seats for mounting valves regulating the blood flow through the pump
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A blood pump, in particular a pneumatic ventricular assist device ( 1 ) has a cap ( 2 ), which has an air chamber ( 4 ) and a blood chamber ( 3 ), separated by a membrane mounted around the perimeter of the cap ( 2 ). The blood chamber ( 3 ) of the cap ( 2 ) has an inlet channel ( 5 ) and an outlet channel ( 6 ) for blood, which channels have circular seats ( 7, 8 ) for mounting valves regulating the blood flow through the device ( 1 ). To the inlet channel ( 5 ) and the outlet channel ( 6 ) are connected with their first ends the connectors ( 9 ) used for joining the pump to cannulas connecting the pump with the circulatory system of a patient. The diameter ( D 1 ) of the seat ( 7 ) for the valve in the inlet channel ( 5 ) is smaller than the diameter ( D2 ) of the seat ( 8 ) for the valve in the outlet channel ( 6 ), whereas the inside channel of each connector ( 9 ) along the full working length thereof is uniformly convergent towards the second end of said connector ( 9 ).