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