Team Members: Jon Klein Nguyen Vu Kyle Menges Christine Lowry Chris Stein Priya Narasimhan Julie Coggshall Week 4 Presentation:  Selected Concepts  Engineering Analysis  Risk Assessment

2 Loops (R)3 Loops 1 Loop Selection CriteriaWeightRatingNotesRatingNotesRatingNotes Easy to Operate15%0 More valves to manipulate 1 Less valves to manipulate Ease of Implementation8%0 Needs additional resistance Needs compliance chamber volumes to be small for blood Maintainability5%01 Less subsystems make contact with Blood More subsystems make contact with Blood Closed System - Minimize Connections15%0 More connecting points 1 Less Connection Points Amount Biocompatible25%01 Automated Resistance doesn't need to be biocompatible Need to make Physiological Simulator biocompatible Volume (of liquid)2%0 Requires extra tubing and valves 1 Requires less tubing and valves Space Required5%00 Same amount of large components 0 Safety10%00 No additional risks or benefits 0 Cost15%00 Cost of valves is small 0 Cost of valves/resistor is small Total Score Rank 1 32 Continue? Yes

Subsystem Rank 123 TubingTygonABSMetal ResevoirBagsGravity DrivenOpen Top Valves3 Way Plastic3 Way StainlessNo Valves ComplianceTanksElastic MaterialMembrane Tanks ResistancePressure CuffServo Controlled ClampClamp Blood ExtractionThree Way ValvePressure Sensor TubingDouble Check Valve Pressure SensorsIntrusive DifferentialIntrusive DisposableSuspended Transducer Flow SensorsUltrasonic Clamp-onIntrusive PTFE Temperature SensorsThermocoupleInfrared Temperature ControlHeat ExchangerHot PlateWater Bath Leak TestTracer-FluidPressure Decay/FlowBubble Test See Concept Selection Matrix for full analysis

Resistance Calculations V air =Volume of air in tank A tank = Cross sectional area of tank V tank =Volume of tank P fluid =absolute pressure of fluid Tank size Calculations = density of fluid g=Acceleration due to gravity C= Compliance P air =absolute pressure of air Source: University of Virginia Article, Design Initial testing of a mock human circulatory loop to test LVAD performance Source: Berne R. etal Physiology 4 th edition Mosby, St Louis 1998

Risk Scoring Parameters Severity (choose most severe) Risk Ranking Likelihood ProductProjectInjury 3 Highly Likely > 50% Complete product failure, does not function Complete project failure Severe injury, potential death 2 Somewhat Likely 20% - 50% Meets some customer needs and specifications, product performs with less functionality than desired Moderate impact to budget schedule Treatment required 1 Rare % Performance of product is not impacted No impact to project budget or schedule Minor or no injury Score level to Change Color: LikelihoodSeverity RPN Red337 Yellow224 Green111

Summary Likelihood (1-3) Severity (1-3) RPN Total Number of 3's2362 Risk ItemDescription/Comment Likelihood Severity Level Risk Priority Number Cost SensorsDesired sensor accuracy not within budget224 DAQDedicated DAQ system not within budget339 Temperature Control Method for keeping constant temperature (98 deg F) not within budget224 Resistance Automation Controlling the flow restriction (resistance) using DAQ not within budget326 Physiological Simulation ComplianceSpecified compliance values not achieved224 ResistanceSpecified resistance values not achieved224 TemperatureHuman body temperature is not maintained224 Viscosity Viscosity variation does not simulate human blood properties122

Risk ItemDescription/Comment Likelihood Severity Level Risk Priority Number Materials Biocompatibility Not all necessary components are biocompatible224 DurabilityValves, sensors, tubing degrade over time122 Measurement Inaccurate measurements Pressure and flow measurements are inaccurate122 DAQ Error Instrumentation and DAQ not communicating properly, DAQ does not collect or output data properly236 Design Robustness System is not robust - variations in functionality and system output224 Leak System or components leak causing error in measurement and/or contamination224 Resistance Automation Flow restriction is not automated or does not function properly133