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Jon Klein ISE Project Manager
Nguyen Vu ME Technical Lead
Kyle Menges ME Technical Lead
Christine Lowry ME Design Engineer
Chris Stein ME Design Engineer
Priya Narasimhan
EE Electrical Engineer
Julie Coggshall ISE Systems Engineer
•Customer Needs•Top 10 Specifications•Blood Sub-System•Physiological Sub-System •LVAD Test Loop•System Architecture•Risks and Mitigation•Design Reviews Summary•Budget•Current State of Design•Senior Design II Schedule
Design and build a test loop to help in LVAD development by characterizing the pressures and flows associated with the device as well as its impact on blood.
1. Generate pressure and flow curves for static system (automatically adjusted)
2. Extracting fluids while running to determine damage to blood
3. Process data to generate pressure and flow curve for dynamic system (scaled model of the physiological circulatory system working with a PVS)
Engr Spec #
Metric UnitsIdeal Value
LowerLimit
UpperLimit
ES1 System Leakage# leak
locations0 0 2
ES6 Portability minutes 45 1 60
ES9 Cost U.S. Dollars 2000 1000 3000
ES13 Pressure mm Hg 100 0 200
ES14 Pressure Accuracy mm Hg 0.2 0.001 0.5
ES15 Flow Rate liters/minute 6 0 10
ES16 Flow Rate Accuracy liters/minute 0.05 0.001 0.1
ES17 Temperature degrees C (F) 37 (98.6) 21 (70) 49 (120)
ES18 Temperature Accuracy degrees F 0.1 0.01 0.5
ES22 System LxWxH inches 48x36x3036x12x1
260x48x3
6
Principle Schema
B-Automated resistance
A-LVAD
D- Temperature controlled bath
C-Reservoir
/Blood extraction
DC
A
B
Differential pressure sensor
Flow sensor
Blood reservoir/ Water bath
B
A
C
• Heating Element (A)• Blood reservoir: fill the system, air removal, blood extraction (B)• Circulation Pump (C)• Water bath: maintain the temperature of the blood (D)
D
• Glycerin mix (A) • Arterial Compliance tank (B)• Pressure regulator (C)• Resistance (D)• PVS (E)• LVAD (F)
A
BC
D
EF
Valved quick-connect Drainage Points
DAQDAQMechanical
System
Test loop with LVAD and PVS
Mechanical System
Test loop with LVAD and PVS
Stepper motor
Stepper motor
Pressure sensor
Pressure sensor
Flow sensorFlow
sensor
Thermocouple
Thermocouple
Computer: Labview used to monitor temperature and plot flow
and pressure curves
Pressure of liquid
Flow rate of liquid
Temperatureof liquid
Variable resistance
Risk Area Risk Item Description/Comment Mitigation Activity
Measurement
Inaccurate measurements
Pressure and flow measurements are inaccurate
Use proper instrumentation and verify proper placement. Discuss with experts prior to purchasing.
DAQ Error
Instrumentation and DAQ not communicating properly, DAQ does not collect or output data properly
Debug software, document procedure for DAQ operation and troubleshooting. Discuss with experts prior to purchasing.
Risk Area Risk Item Description/Comment Mitigation Activity
PhysiologicalSimulation
Compliance TankDesired compliance value not achieved
Early milestone in test plan to ensure enough time to fix the problem
TemperatureSystem temperature is not maintained
Monitor fluid and VAD temperature, implement temperature control system
ViscosityViscosity variation does not simulate human blood properties
Research and verify the proper mixture of water/glycerin is used, control/maintain temperature
Risk Area Risk Item Description/Comment Mitigation Activity
Design
Leaks
System or components leak causing error in measurement and/or contamination
Early milestone in test plan to ensure enough time to fix the problem
Air bubbles
Air bubbles cannot be removed from system – tank sizes do not allow for bubbles to escape, or there are low points in the system
Early milestone in test plan to ensure enough time to fix the problem. Use alternative fill method to reduce bubble formation
Blood DamageValves, sensors, connectors damage blood
Early milestone in test plan to ensure enough time to fix the problem. Put in separate, simplified loop
ResistanceFlow restriction does not function properly
Design for the implementation of a back-up, manually controlled resistance method
Risk Area Risk Item Description/Comment Mitigation Activity
Cost
Pressure SensorsDesired sensor accuracy not within budget
Find suitable DAQ to achieve accuracy
DAQDedicated DAQ system not within budget
Investigate costs, potential for sharing existing DAQ system
DR1 Compliance: Developed electrical equivalent model Sensors: Use existing flow sensors System Architecture: Modular, quick-connect design
DR2 Simplify Design:
• Reduce system to a single tank that functions as both a compliance tank and reservoir• Use a pressure-cuff to pressurize compliance chamber in place of expensive gauge and regulator
Need to establish more refined electrical specifications
Component DescriptionTotal Price
General Components Tubing, Connectors, Fittings, Tank, Cart $688.87
Measurement & Data Collection
Sensors (Pressure, Thermocouples, Ultrasonic Flowmeter), DAQ
$1,908.30
Blood Loop Components Water Bath, Heating Element, Pump, Tank Fittings $398.40
Physiological Loop Components
Pressure Cuff & Gauge, Fittings (for Tank) $32.27
Automated Resistance Linear Actuator & Stepper Motor, Stand $97.73
Testing Supplies Glycerin, De-Ionized Water, Saline $195.96
TOTAL$3,170.$3,170.
2828
• Design meets all customer needs• Design exceeds upper budget limit by ~ 6%• Data collection and control specifications are not finalized• Schedule: 1 week behind on electronic component selection• Mitigations:
• Elimination of venous compliance tank → pending approval• Budget: Need approval or reduction in specification limits• Finalize design by end of week 11 to order parts
Date(Week) Mechanical System Data Collection and Control
Mar 13(Week 1) Closure of MSD I A.I.’s, All Parts from BOM Ordered
Mar 20 (Week 2) All Parts Received All Parts Received
Apr 3 (Week 4) Loop Components Assembled
Connection with PVS and LVAD established
Apr 5 (Week5) Final Test Plan complete
Apr 24 (Week 6) Compliance Confirmed Connection with Sensors established
May 3 (Week 8) Final Device Built Lab View Program debugged
May 8 (Week 9) Testing Complete & Documented, Poster Complete
May 15 (Week 10)
Field Demo, Technical Paper, User Manual
May 18 (Week 11)
Final Documentation
Heating Element
Blood Extraction
Resistance
Female - Valved
Male - Valved
Female
Male
Fluid Fill
LVAD
PVS