1. MSD Project 13022 VAD BREAKAWAY POWER Detailed Design Review 2/8/2013
Joe Tartakoff
Customer/Graduate Consultant
Matthew Myers
ISE Project Leader
Nick Dominesey
ME Lead Engineer
Jason Inman
EE Team Member
Chris Smith
ME Team Member
Ellie Sanford
Michael Edson
Matt
2/8/2013

2. MSD Project 13022: Breakaway VAD
Agenda
MSD1 Final Review /15/2013
Project Overview
Customer Needs, Engineering Specs & Testing Plan
Chosen Concept
Block Diagram and Circuit Diagram*
Feasibility Analysis
Work Breakdown Structure*
System Design Proposal*
Bill of Materials*
Risk Assessment*
Plan for MSD2 Weeks 1-3*
Matt
*new from Detailed Design Review Presentation
MSD Project 13022: Breakaway VAD

3. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
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.
Ellie
MSD Project 13022: Breakaway VAD

4. Present LVAD External Power
MSD1 Final Review /15/2013
Present LVAD External Power
Ellie
MSD Project 13022: Breakaway VAD

5. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
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.
Ellie
MSD Project 13022: Breakaway VAD

6. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
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
Ellie
MSD Project 13022: Breakaway VAD

7. MSD Project 13022: Breakaway VAD
Customer Needs
MSD1 Final Review /15/2013
Matt
MSD Project 13022: Breakaway VAD

8. MSD Project 13022: Breakaway VAD
Engineering Specs
MSD1 Final Review /15/2013
Matt
MSD Project 13022: Breakaway VAD

9. MSD Project 13022: Breakaway VAD
Needs and Specs
MSD1 Final Review /15/2013
Matt
MSD Project 13022: Breakaway VAD

10. MSD Project 13022: Breakaway VAD
Chosen Concept
MSD1 Final Review /15/2013
Jason
Note Regarding Heat Control: Battery Recharging will cease if Temperature exceeds limit.
MSD Project 13022: Breakaway VAD

11. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
Block Diagram
Legend:
Existing Action
New Action
Existing Device
New Device 10 10
Mike
40oC
MSD Project 13022: Breakaway VAD

12. Circuit Wiring Diagram
MSD1 Final Review /15/2013
MSD Project 13022: Breakaway VAD

13. Battery Discharge Feasibility Test Results
Battery Discharge Time Data
Time(Min)
Voltage(V)
13.300 4
13.200 6
13.165 7
13.155 8
13.140 10
13.135 31
13.117 50
13.054 86
13.040
151
12.993
168
12.839
194
12.772
196
12.493
203
12.434
209
11.950
MSD Project 13022: Breakaway VAD

14. Specs vs Subcomponents
MSD1 Final Review /15/2013
Specs vs Subcomponents
Mike
MSD Project 13022: Breakaway VAD

15. Force Pull Test on Skin - Angles
MSD1 Final Review /15/2013
Force Pull Test on Skin - Angles
MSD Project 13022: Breakaway VAD

16. Force Pull Test on Skin - Results
MSD1 Final Review /15/2013
Force Pull Test on Skin - Results
Angle of Disconnect
Force (N)
Displacement of
skin (mm)
Feeling Assessment
Comments
90 degrees 1
light 2 5
medium
2.5 10
med-heavy 3
heavy
3.5 12
too heavy 4 15
45 degrees -
light-med.
reasonable disconnect
upper limit
0 degrees
very light
barely feel it
Nick
Upper spec of 3 N chosen because it was usually the upper limit for pain tolerance. Lower limit is 1 N because that’s when it started to feel uncomfortable. Angle of 0 degrees was chosen as the ideal angle because applied force tends to induce the least amount of stress on the body at this angle.
MSD Project 13022: Breakaway VAD

17. Heat Analysis - Assumptions
MSD1 Final Review /15/2013
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 VAD

18. Heat Analysis – Additional 1D Assumptions
MSD1 Final Review /15/2013
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 VAD

19. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
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=10.000
MSD Project 13022: Breakaway VAD

20. Heat Analysis – Critical Values
MSD1 Final Review /15/2013
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/cm2
MSD Project 13022: Breakaway VAD

21. Heat Analysis – 1D Analysis Model
MSD1 Final Review /15/2013
Heat Analysis – 1D Analysis Model
MSD Project 13022: Breakaway VAD

22. Heat Analysis - Results
MSD1 Final Review /15/2013
Heat Analysis - Results
MSD Project 13022: Breakaway VAD

23. Heat Analysis – Engineering Model
MSD1 Final Review /15/2013
Heat Analysis – Engineering Model
Boundary Temp: 37˚C
Conduction
Device
Internal Environment
(Abdomen Muscle)
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
MSD Project 13022: Breakaway VAD

24. Heat Analysis - Summary
MSD1 Final Review /15/2013
Heat Analysis - Summary
For the given area of 64cm2 , 0.3 W (4.67mW/cm2) of heat generation will be dissipated before exceeding 40oC.
For a surface area of 340cm2 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 VAD

25. Heat Analysis - Conclusion
MSD1 Final Review /15/2013
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 VAD

26. Antenna Radiation Analysis
MSD1 Final Review /15/2013
Antenna Radiation Analysis
Antenna Radiation-Heat Energy Analysis
Given:
Radiation Energy, q = 10mW
Maximum Heat Flux, q” = 40 mW/cm^2
Length of wire = 25cm
Find:
Diameter of wire to account for surface area needed to dissipate energy.
𝑟= 𝑞 2𝜋ℎ𝑞" = 10𝑚𝑊 2∗𝜋∗25𝑐𝑚∗40𝑚𝑊/ 𝑐𝑚 2 =0.0016𝑐𝑚
𝐷=0.0032𝑐𝑚=0.032𝑚𝑚
Result: Diameter must be at least 0.032mm.
MSD Project 13022: Breakaway VAD

27. MSD Project 13022: Breakaway VAD
Wire Gauge Analysis
Based on the shielded wire that we plan on ordering from awcwire.com and its thickness, it will allow us to use 20 AWG wire without exceeding our heat flux limit.
MSD Project 13022: Breakaway VAD

28. Work Breakdown Structure - Chart
MSD1 Final Review /15/2013
MSD Project 13022: Breakaway VAD

29. Work Breakdown Structure - Diagram
MSD1 Final Review /15/2013
Work Breakdown Structure - Diagram
*On Edge currently
MSD Project 13022: Breakaway VAD

30. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
System Model
Mike
MSD Project 13022: Breakaway VAD

31. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
System Model (sketch)
Existing Batteries
Internal Pump
(Thoratec Heartmate 2)
Internal Signal Controller & Batteries
Breakaway Port
Mike
External Signal Controller
External Pump Monitor
MSD Project 13022: Breakaway VAD

32. Internal Power Control Case Configurations
MSD1 Final Review /15/2013
Internal Power Control Case Configurations
Mike
MSD Project 13022: Breakaway VAD

33. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
Port Design Options
Angled Port
Cup Port
Straight Port
Flat Port
MSD Project 13022: Breakaway VAD

34. Breakaway Port Selection
MSD1 Final Review /15/2013
Breakaway Port Selection
Port Design
Measures of Evaluation
Straight
Cup
Angled
Flat
Functionality 2 4 3 1
User Friendly
Ease of Production
Stress on Body
Cost Value
Total Score 11 12 14
Definitions:
Functionality
The cable will remain connected under most circumstances.
User Friendly
Relates to how likely the cable is to catch on objects and is dependent on the angle of the wire coming out of the port.
Ease of Production
Relates to how easy it will be for us to manufacture the port.
Stress on Body
Relates to the amount of stress that is expected to occur due to snags or brushing the port and is dependent on the amount of material on the female port that is protruding from the body.
Cost Value
Antipated cost after purcasing and manufacture and includes amount of time we would have to spend making the part.
MSD Project 13022: Breakaway VAD

35. Breakaway Port Design Selection
MSD1 Final Review /15/2013
Breakaway Port Design Selection
Mike
MSD Project 13022: Breakaway VAD

36. Expert Recommendations
MSD1 Final Review /15/2013
Expert Recommendations
MSD Project 13022: Breakaway VAD

37. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
Bill of Materials
MSD Project 13022: Breakaway VAD

38. MSD Project 13022: Breakaway VAD
MSD1 Final Review /15/2013
Risk Assessment
MSD Project 13022: Breakaway VAD

39. Vision for MSD2 Weeks 3 Demo.
MSD1 Final Review /15/2013
Vision for MSD2 Weeks 3 Demo.
Shared Vision for Week 3
The goal is to have all functional properties separated into their respective working models.
Plastic Prototype of Port with Magnets
Minimize the size in an effort to save every last millimeter of space and reduce overall size of plug and jack.
Design smooth form prototypes if possible.
Internal Device Housing Prototype.
Plastic mockup to spec.
For large batteries and/or AA battery size.
Electrical Function Prototype.
Battery charging circuit.
Pump controlling circuit.
MSD Project 13022: Breakaway VAD

40. MSD Project 13022: Breakaway VAD
Plan for MSD2 Weeks 1-3
Three (3) Week Plan in Order to Reach our Shared Vision of the Week 3 Demonstration:
Week 1:
Create 3 detailed drawings with exact specs of all port part parameters so that the port alpha prototype designs are ready for machining.
3 drawings may include:
Our 1st choice of design.
Dr. Duncan’s recommended design.
Surgeon’s recommended design or our 2nd choice of design.
Conceive and document all possible trade-offs associated with each design.
Capture and summarize.
Produce a nice little table.
Confirm Schedule of week 2 meeting with all involved parties (Dr. Day, Dr. Duncan, Surgeon, Joe, Mr. Hanzlik, team, etc.)
Create detailed drawing of internal housing, including battery holders if necessary.
Complete geriatric research.
Determine influence on design.
Give the go-ahead to produce prototypes.
MSD Project 13022: Breakaway VAD

41. MSD Project 13022: Breakaway VAD
Plan for MSD2 Weeks 1-3
Week 2:
Rapid Prototype the 3 port designs by Thursday.
Hold meeting with all involved parties (Dr. Day, Dr. Duncan, Surgeon, Joe, Mr. Hanzlik, team, etc.)
Get feedback about designs.
They should be able to make a proper assessment with scaled 3D physical models at their disposal.
Walk out with a winner and final design.
Rapid Prototype the Internal Housing.
Week 3:
Demonstrate all sub-level functions (as described above in the Shared Vision)
Breakaway Port Plastic Prototype.
Internal Housing.
Electric Components.
MSD Project 13022: Breakaway VAD

42. System Model (sketch) I love my new breakaway port system!
MSD1 Final Review /15/2013
System Model (sketch)
I love my new breakaway port system!
Hanzlik in 20 years.
Mike
MSD Project 13022: Breakaway VAD