Joe TartakoffCustomer/Graduate Matthew MyersISE Project Nick DomineseyME Lead Jason InmanEE Team Chris SmithME Team Ellie SanfordME Team Michael EdsonEE Team

Agenda 1. Project Overview 2. Customer Needs and Engineering Specifications 3. Chosen Concept 4. Block Diagram 5. Feasibility Analysis 6. Testing Plan 7. Work Breakdown Structure 8. System Design Proposal 9. Bill of Materials MSD Project 13022: Breakaway VAD2 Detailed Design Review 2/8/2013

Project Background  6-10% of all people worldwide over the age of 65 will develop heart failure.  There are 287,000 deaths per year due to heart failure in the US.  The Thoratec Heartmate II Left Ventricular Assist Device (LVAD) is a bridge-to-transplant device that assists the heart, pumping blood throughout the body for those who are awaiting a heart transplant. MSD Project 13022: Breakaway VAD3 Detailed Design Review 2/8/2013

Present LVAD External Power MSD Project 13022: Breakaway VAD4 Detailed Design Review 2/8/2013

Project Summary  The transcutaneous power cord that connects the implanted device to the external motor control unit is often a source of infection. The cord is only about 1 foot long so it doesn’t catch on things. When the unit is dropped, the skin around the cord tears and becomes infected. MSD Project 13022: Breakaway VAD5 Detailed Design Review 2/8/2013

Project Objectives  Create a breakaway port for power cable that will detach with a certain amount of force. Cable port is implanted where the cable leaves the body Increase flexibility of cable and reduce stress on surrounding skin  Create an internal power supply and motor control unit for the pump when the cord becomes disconnected. Backup power should last long enough for the patient to seek assistance if something goes wrong MSD Project 13022: Breakaway VAD6 Detailed Design Review 2/8/2013

Customer Needs MSD Project 13022: Breakaway VAD7 Detailed Design Review 2/8/2013

Engineering Specs MSD Project 13022: Breakaway VAD8 Detailed Design Review 2/8/2013

Needs and Specs MSD Project 13022: Breakaway VAD 9 Detailed Design Review 2/8/2013

Notes  Is CN2 a redundant statement of CN1 and therefore unnecessary? Wouldn’t a reduction of inflammation be accomplished by reduced the force on the port?  CN5 is something that we may not be able to test or implement. Therefore, is it necessary?  CN10 sounds like something that’s left up to the surgeons. We can’t really test or implement this in a practical manner…  CN12 is being removed because it is not our concern. We will assume that there is no fluid or that there are existing methods that can be implemented to solve the situation.  S11 may be removed because it may be completely unnecessary and we can’t test for it.  S2 is may not be considered a concern due to physical observations of the current cord. MSD Project 13022: Breakaway VAD10 Detailed Design Review 2/8/2013

Chosen Concept MSD Project 13022: Breakaway VAD11 Detailed Design Review 2/8/2013 Note: One of the electrical methods has changed. I believe it is under “Manage Switchover” > “Pump Control Switchover” > changed to “External to Internal Relay”

Block Diagram MSD Project 13022: Breakaway VAD 12 Detailed Design Review 2/8/2013 Note: Some of the numbers of wires have been reduced.

Specs vs Subcomponents MSD Project 13022: Breakaway VAD13 Detailed Design Review 2/8/2013

Force Pull Test on Skin Angle of Disconnect Force (N) Displacement of skin (mm) Feeling AssessmentComments 90 degrees 11light 25medium 2.510med-heavy 310heavy 3.512too heavy 415too heavy 45 degrees 1-light 2-light-med.reasonable disconnect 3-mediumupper limit 4-med-heavy 5-heavy 0 degrees 1-very lightbarely feel it 2-lightreasonable disconnect 3-mediumupper limit 4-med-heavy 5-heavy MSD Project 13022: Breakaway VAD14 Detailed Design Review 2/8/2013 Explain why upper and lower limits, and angle were chosen.

Heat Analysis - Assumptions  Body Temperature (Environment) is 37˚C  Heat distribution on outside of device will be modeled via FEA  Heat transfer method inside body is conduction  All energy inefficiencies result in heat generation  Device is surrounded my muscle tissue which is at equilibrium between perfusion and heat generation MSD Project 13022: Breakaway VAD15 Detailed Design Review 2/8/2013

Heat Analysis – Additional 1D Assumptions  1 dimension normal to the skin  Uniform heat generation  Constant Properties  Body is at equilibrium (neglect heat generation effects)  Steady State MSD Project 13022: Breakaway VAD16 Detailed Design Review 2/8/2013

Heat Analysis - Data  Reference Temperatures[C]:  Body Temp= 37 C  Ambient Air Temp= 25 C  Conduction Coefficients :  Internal Organs and Muscle = W/m*K  Skin and Fat=0.300 W/m*K  Titanium= W/m*K (P13022 only)  Clothing=0.029 W/m*K  Convection Coefficients [W/m*K]:  Air= MSD Project 13022: Breakaway VAD17 Detailed Design Review 2/8/2013

Heat Analysis – Critical Values The purpose of our thermal model is to ensure this device will not harm the patient. With a factor of safety of 2, our maximum heat flux through the tissue is 40mW/cm 2 MSD Project 13022: Breakaway VAD18 Detailed Design Review 2/8/2013

Heat Analysis – 1D Analysis Model MSD Project 13022: Breakaway VAD19 Detailed Design Review 2/8/2013

Heat Analysis - Results MSD Project 13022: Breakaway VAD20 Detailed Design Review 2/8/2013

Heat Analysis – Engineering Model MSD Project 13022: Breakaway VAD21 Conduction Internal Environment (Abdomen Muscle) Device Boundary Temp: 37˚C The Device will be implanted in abdomen muscle Assuming a worst case scenario, the device will be surrounded by muscle tissue in all directions for an “infinite” thickness. An ANSYS model which includes the boundary temperature of 37˚C and all muscle properties will show worst case temperature and flux conditions Detailed Design Review 2/8/2013

Heat Analysis - Summary  For the given area of 64cm 2, 0.3 W (4.67mW/cm 2 ) of heat generation will be dissipated before exceeding 40 o C.  For a surface area of 340cm 2 we should be allowed to generate up to 13.6 W of heat energy within the device.  Expected worst case heat generation = 2 W. MSD Project 13022: Breakaway VAD22 Detailed Design Review 2/8/2013

Heat Analysis - Conclusion  The Internal Battery Storage Device is not likely to harm the body through heat generation based upon the of energy flux through the total surface area.  Further analysis will be conducted (in ANSYS) to confirm the results.  Due to the extreme difficulty of finding a relatively accurate model for the body in relation to the LVAD system, the 1-D analysis is only useful for worst case results and only provide limited useful data.  Further analysis in ANSYS should provide more reliable results.  Development of the P13022 device should continue with minimal design change. MSD Project 13022: Breakaway VAD23 Detailed Design Review 2/8/2013

Testing Plan MSD Project 13022: Breakaway VAD24 Detailed Design Review 2/8/2013

Work Breakdown Structure MSD Project 13022: Breakaway VAD25 Detailed Design Review 2/8/2013

System Model MSD Project 13022: Breakaway VAD26 Detailed Design Review 2/8/2013

System Model (sketch) MSD Project 13022: Breakaway VAD27 Detailed Design Review 2/8/2013

Internal Power Control (sketch) MSD Project 13022: Breakaway VAD28 Detailed Design Review 2/8/2013

Breakaway Port Design MSD Project 13022: Breakaway VAD29 Detailed Design Review 2/8/2013

Bill of Materials MSD Project 13022: Breakaway VAD30 Material:Quantity:Price per unit:Total cost:Comments: Batteries8$3.50$28.00 LiFePO Rechargeable Cell: 3.2V 1500 mAh, 4.5A Rate, 4.32Wh, UL Listed, UN Approved (NDGR) Part Number: LFP Polycarbonate/Acrylic1$0.00 Old scrap piece will be used unless more models needs to be made. motor controller design board1$ used to design the motor controller Bio-compatable titanuim roundstock 1$23.10 For implant 1.25"D X 1.00"L pid=6776&step=4&showunits=inches&id=18 7&top_cat=0 Recharge Board1$6.45 PCB (Protection circuit module) for 4 cells (12.8V) LiFePO4 Battery Part Number: PCB-LFP12.8V2A Surgical tubing1$ Surgical-Tubing /dp/B0045V36PQ Detailed Design Review 2/8/2013

Bill of Materials (cont’d) MSD Project 13022: Breakaway VAD31 Material:Quantity:Price per unit:Total cost:Comments: Wire1$ ft, 16 gauge wire Magnets5$1.00$5.00 Microcontroller2$20.00$40.00 Relay1$17.19 Resistors $0.00 Capacitors $0.00 Thermocouple $0.00 Connectors $0.00 PBC board1$50.00 Vibrating motor2$3.99$ nd 10-pin connector $0.00 Total: $ Detailed Design Review 2/8/2013

System Model (sketch) Hanzlik in 20 years. MSD Project 13022: Breakaway VAD32 I love my new breakaway port system! Detailed Design Review 2/8/2013