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Project # P09021
To complete this project, our project team identified the customers needs and specifications , conceptualized development and selection of materials, created a systems design, and built and tested the model.
The construction of the test loop is integral to the development of magnetically levitated axial low
LVAD because the machine is able to characterize the pressures and flows associated with the device
and determine the pumps impact on blood.
This Project builds off of the work of previous Senior Design Projects. Past projects have created a durability tester for LVAD, a centering magnet device and a hemodynamic flow simulation systems. The findings of University of Virginia Article, “Design Initial Testing of a Mock Human Circulatory Loop to Test LVAD Performance” has also been integral to our design choices.
Results concluded that there is adequate flow of pressure within the system to allow adjustments to be made through testing to compensate for the non-steady characteristics.
Location of PVS for Physiological Test
LVAD with custom connections
Differential pressure sensor to characterize pump performance
Quickconnect point for draining and connecting PVS
Pressure sensor to ensure compliance is achieved
Water bath with heater and circulator to heat blood
Reservoir/Compliance chamber with interchangeable lids; One has blood extraction needle, Second has hand pump and air gage to ensure compliance is achieved
Location of Flow sensor to characterize pump performance
Automated resistance
Thermocouple for temperature of fluid
One Loop OptionTwo Loop Option
Three Loop Option
Two Tank Design
One Tank Design
Design Conceptions differed by the number of loops and
orientation. The Final Design was chosen using Pugh charts.
Subsystems include:
Blood Sub-System elements of •materials and blood extraction.
Dynamic Sub-System elements of •compliance chambers.
Static Sub-System Elements include air •removal and automated resistance.
Electrical elements of flow, pressure and •temperature sensors as well as the DAQ.
The final product is modular, biocompatible, has quick connects and a single tank that uses test
specific tank lids. (See labeled diagram on the left). It is all controlled by a single LabView program.
Heat Transfer Calculations were performed to determine the heat transfer that occurs within the loop.
The test concluded that bubbles of significant size(5mm) will have enough time to rise in our reservoir.
The Electric Model was used to determine what loop design was needed in order to model the human circulator system.
Automate air pressure in physiological •test
Build loop vertically to shrink footprint •and improve fill/drain time
Automate termperature control, add •cooling
Further reduce resistance in loop to •increase range of automated curve generation
Vertical Design
Initial Concepts
Team Members:
Jonathan Klein - Industrial and Systems Engineering
Kyle Menges - Mechanical Engineering,
Dinh Nguyen Vu - Mechanical Engineering
Christine Lowry - Mechanical Engineering
Christopher Stein - Mechanical Engineering
Priyadarshini Narasimhan - Electrical Engineering
Julie Coggshall - Industrial and Systems Engineering.
The team would like to express its appreciation and gratitude to those who contributed to this project. Special thanks to Dr.. Steven Day for his guidance and support, and Ivan Farber from Oetiker Inc., for his generous donation of components and installation tools. Additionally, the team would like to thank Dr. Richard Doolittle, Dr. Daniel Phillips, Mr. John Wellin, Mr. David Hathaway, Mr. Robert Kraynik, Mr. Steven Kosciol, and the entire VAD research team for their assistance, patience, cooperation and constructive criticism.
Project Customer and Sponsor: Steven Day
Fluid calculations were performed to test if there is an adequate flow of pressure within the system.
Bubble Dissipation Calculations were performed to determine the reservoir size needed for air to escape.
The Heat Transfer of Compliance tank results concluded that the time for the blood loop to heat is less than two hours. A slow temperature rise will be less likely to damage the blood. Lastly, it was determined that no significant heat life occurs in the tubing.
The main finding was that the loop only requires an Arterial Compliance Tank.
Design Calculations Tests Performed Next Steps
Data from the automated performance curves, derived using the Biomedicus in place of the LVAD for four different rotational speeds, shows that the data points are overextended, thus the cap on the stepper motor is not wide enough to completely close the tubing.
0
50
100
150
200
250
0 2 4 6 8 10
Pres
sure
-mm
Hg
Flow - Lpm
Biomedicus Performance Curve
500 rpm 1000 rpm 1500 rpm 2000 rpm
500 rpm SD 1000 rpm SD 1500 rpm SD 2000 rpm SD
After two three hour hemolysis test using both the LVAD and Biomedicus, the percent hemolysis for our test loop was slightly lower than that of the LVAD research team’s simplistic loop. This indicates that the loop itself does not have a significant effect on hemolysis.
37.5
37 (98.6)
0.05
+/-6
0.2
1.75
48x36x30
45
0
Ideal Value
32
– 328 to 662
.1
+/-10
0.4
1.8
48x36x30
30
0
ResultCustomer Needs Specifications Units
Test device needs to be self contained and portable, minimize volume of fluids, and be easy to fill and drain
System Leakage # leak locations
Portability minutes
Automatically generate pressure and flow curves to help characterize pump
System LxWxH inches
Blood System Volume Liters
Able to run with and without Pulsatile Ventricular Simulator and simulate physiological properties of the human body (i.e., temperature, resistance, compliance)
Pressure Accuracy mm Hg
Flow Rate Range liters/minute
Flow Rate Accuracy liters/minute
Consist of Biocompatible components to minimize blood damage and extracting blood while running.
Temperature Range degrees C (F)
Sample Extraction Time Seconds 37.5
37 (98.6)
0.05
+/-6
0.2
1.75
48x36x30
45
0
Ideal Value
32
– 328 to 662
.1
+/-10
0.4
1.8
48x36x30
30
0
ResultCustomer Needs Specifications Units
Test device needs to be self contained and portable, minimize volume of fluids, and be easy to fill and drain
System Leakage # leak locations
Portability minutes
Automatically generate pressure and flow curves to help characterize pump
System LxWxH inches
Blood System Volume Liters
Able to run with and without Pulsatile Ventricular Simulator and simulate physiological properties of the human body (i.e., temperature, resistance, compliance)
Pressure Accuracy mm Hg
Flow Rate Range liters/minute
Flow Rate Accuracy liters/minute
Consist of Biocompatible components to minimize blood damage and extracting blood while running.
Temperature Range degrees C (F)
Sample Extraction Time Seconds
http://edge.rit.edu/content/P09021/public/Home
Succesfully ran LVAD with PVS, demonstrated ability to achieve resistance and compliance values.
Left Ventricular Assist Device Test Loop
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