2. Client: Ken Campbell, Ph.D. Advisor: Glennys Mensing
Team Mouse Heart:
Michael Kosir
Ankur Sharma
Steve Trier

3. Problem Definition
To design a device that can rapidly pump saline into a catheter for stiffness measurements during specific intervals in the cardiac cycle.
Inject 3 L of saline in less than 5 ms
Remove injected portion
Stiffness = ∆P/∆V
-Already a device to measure ∆P
-Need a device to cause a ∆V

4. Background/Motivation
Diastolic Dysfunction:
Impaired ventricular filling
Decreased stroke volume from LV
Greater end-diastolic pressure
Cause:
Delayed ventricular relaxation and stiffness of ventricular walls
Implicated in more than 70% of heart failure patients that are 80+

5. Design Specifications
Inject a fixed quantity (3-5 µl) of saline through a catheter into a left ventricular balloon
Operate in less than 5 ms
Attach to a catheter with 200 µm diameter opening
Must operate with an electrical logic pulse
Length of catheter from fluid injector to end of tube is at least 2-3 cm

6. Design Overview
Source: Campbell, 2003

7. Size Comparison
Mouse Heart
Catheter: Inserted Into Left Ventrical

8. Previous Design Circuit Micro Solenoid Valve Pressure Source
To Catheter

9. Previous Design Advantages: Disadvantages: Rapid response time
Simple circuitry required
Compact
Cheap
Disadvantages:
Less Accurate
No Retraction Mechanism

10. (dVs/dt)ds+P+1/2Vs2+gz=C
Flow Analysis
(dVs/dt)ds+P+1/2Vs2+gz=C
A1V1=A2V2
Unsteady Bernoulli’s Equation and Continuity Principle
Cross sectional area of the plunger based on the area of the tubing used
6.0 mm diameter

11. Piezoelectric Stack
Source: Physik Instrumente, Part

12. Piezoelectric Stack Sub-millisecond Response High Force Generation
4500 N Push, 500 N Pull
Extreme Reliability
Max displacement=180 µm
High voltage input
Maximum operating voltage = V
Cost: $2,940.00

13. Current Difficulties LEMO to BNC connector on order
Current amplifier incompatible
Does not handle capacitance of piezo stack
Impedance too large
Requires a relay controlled by TTL trigger to fire stack
Two possible solutions

14. High Voltage Piezo Amplifier
-3 to V output
Up to 50 W peak power
0 to ±11 V control input
50 mA peak output current
Designed for use with piezo actuator
Source: Physik Instrumente, Part

15. Alternate Circuitry 1000V power supply Charge capacitor
Acts as voltage supply
Close transistor with TTL pulse
Capacitor drives piezostack
1000V
stack
capacitor
transistor
TTL input

16. Current Device
Source:

17. What’s Next Ordering piezo stack parts Fabricating piston and nozzle
Syringe
Connecting catheter and nozzle
Operating on logic pulse
Testing

18. Acknowledgments Ken Campbell Burke O’Neil Naomi Chesler John Webster
Glennys Mensing
Machine shop

19. References
Physik Instrumente online tutorial of Piezoelectrics. Available at:
Klabunde, R. (2003). Cardiovascular Physiology Concepts: Diastolic Dysfunction. Retrieved September, 2003, from
Campbell, K. (2003).
Glassey, S., Stockner, A., (2002), HEUI—A New Direction for Diesel Engine Fuel Systems. Developed by Caterpillar Inc. SAE paper (930270).
Arnold, C., (2003). Hydraulically-actuated, Electronically-controlled Unit Injectors. The Power Shop Inc., retrieved October, 2003, from
Biomedical Technical Support Center. “MicroInjection System”, University of Calgary [Electronic Version] Retrieved September 10, 2003 URL:
Parker Hannifin Corporation. “Picospritzer: Operating Manual” [Electronic Version] Retrieved September 16, 2003
URL:
“Eppendorf FemtoJet Microinjections System” Northwestern University Cell Imaging facility. [Electronic Version] Retrieved October 6, URL:
“What Is a Solenoid?” Detroit Coil Company. [Electronic Version] Retrieved October 6, 2003
URL:
The Lee Company. Essex, CT.