April 13, 2004 Design of a Prenatal Perfusion System PROJECT PROPOSAL Timothy Bachman Garrett...
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Transcript of April 13, 2004 Design of a Prenatal Perfusion System PROJECT PROPOSAL Timothy Bachman Garrett...
April 13, 2004
Design of a Prenatal Perfusion System
PROJECT PROPOSAL
Timothy BachmanGarrett GrindleLeigh McClureScott Morley
Bioengineering 1160/61April 13, 2004
April 13, 2004
Overview• The practice of fetal heart surgery to correct
congenital heart defects has been limited by the lack of a fetal CPB system.
• It is believed that if congenital heart defects are corrected early, that blood flow patterns can be restored and the heart will develop normally.
• 2001 Mortality – CHD: 4109• There is an extremely small demand for a fetal CPB
system – probably 100’s of cases per year.
April 13, 2004
Overview (cont)
• This group has designed, constructed, and tested a prototype prenatal perfusion system comprised of:
– Pump
– Venous and arterial cannulas
– Controller• Existing pumps were evaluated and deemed
inappropriate for the application• We have developed a novel, pulsatile pump
April 13, 2004
Project Objectives• Design a cardiac perfusion system capable of
providing ex utero fetal cardiac support for up to 2 hours– Variable, pulsatile flow
• 300 – 1000 mL/min• 120 – 180 BPM• Mean arterial pressure 40 – 50 mmHg
– Minimal priming volume• Less than 15 mL
April 13, 2004
Market and Competition• Research Competitors
– Stanford/UCSF group (one case w/ J&J’s pump)• Commercial Competitors
– Blood pump companies: J&J, Medtronic, Cobe, etc– No competing commercial products at this time
• Strengths and Weaknesses vs. Stanford/UCSF’s Group
– Stanford has not published their work. Our competitive advantage or disadvantage has not yet been determined.
• Catheter-based solutions (Verimetra)
April 13, 2004
Design Concepts Considered
• Existing pumps – Nimbus Centrifugal Pump
• New Pump Design– Rotary or centrifugal (design
too difficult, pulsatility likely difficult to achieve)
– Positive displacement pumps• Imitates ventricle behavior• Inherent pulsatility• Ease of design/construction• Availability of resources
(materials and controller)
Nimbus Centrifugal Pump
April 13, 2004
Design
Solidworks Model (exploded view)
• Pneumatically driven positive displacement pump
• One-way valves direct flow
• 6 mL stroke volume• Compatible with
IMO controller• Modular design for
valve and bladder testing
April 13, 2004
MaterialsChamber: Acrylic stockBladder: Medical grade PUCannulae/Tubing: Off the shelf (Medtronic/Tygon)Valves: Check valves – not medical grade
April 13, 2004
Preliminary Results - Prenatal Perfusion System
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
450.0
0 30 60 90 120 150 180
BPM
Flo
w R
ate
(m
L/m
in)
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7.0
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Str
ok
e V
olu
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(mL
)
Mean Flow (mL/min)
Mean Stroke Volume (mL)
April 13, 2004
Project Mgmt: Schedule and Milestones
• Conceptual Design Complete: Actual: 1/17/04– Choose pump – Cannula size and insertion sites– Determine console requirements
and electrical safe guards• Primary Design Complete: 2/21/04
Actual: 2/15/04– Apply engineering model to
determine dimensions– Determine Specific Components– Preliminary drawing and parts
list
• Design Refinement Complete: 3/13/04– Integrate components – Manufacturing protocol– Final drawings, parts list, and
testing protocol • Prototype Fabricated: Org: 4/6/04
Rev.: 3/21/04 Actual: 4/2/04
• Testing Complete: Org.: 4/12/04Rev.: 4/2/04 Actual: 4/09/04
• Business Plan SBIR Complete: Org.: 4/14/04 Actual: 4/20/04
April 13, 2004
Future Design Work
• Complete pressure/flow characterization in a physiologic mock loop
• Valve evaluations or new valve design• Evaluate bladder design for flow optimization• Redesign pump with integrated valves• Design/build drive system for this specific
application
April 13, 2004
Considerations for Future Development• Economic
– Good project for university level development– Projected market size is very small not commercially
attractive• Manufacturability
– Current product design is relatively simple to manufacture
– Future designs should use medical grade products and be evaluated for durability and sterilization compatibility
– Final manufacturing (for human use) would require a cleanroom
• Human Factors– Console design, setting of use (OR)
• Regulatory Issues– HDE qualification would simplify approval process
April 13, 2004
Regulatory Strategy:Humanitarian Device Exemption (HDE)
• Similar to a pre-market approval (PMA)• Exempt from effectiveness requirements• “intended to benefit patients in the treatment
or diagnosis of diseases or conditions that affect fewer than 4,000 individuals [per year] in the United States” - CDRH
April 13, 2004
Team ResponsibilitiesAction Item Bachman Grindle McClure Morley
Pump Design Lead
Current pump evaluations X X X X
Solid modeling X
CFD if req. if req.
Cannula Design Lead
Evaluation of available cannulas
X X X X
Console Development X
Regulatory and QS X
Mock Loop and Experimental Protocol Design
X
HFE X X
Fabrication and Procurement
Pump X X
Cannulas X
Console X
Prototype Evaluation X X X X
SBIR X
April 13, 2004
Acknowledgements
• Frank Pigula, M.D.Pediatric Cardiothoracic Surgeon, Boston Children’s Hospital
• William Federspiel, Ph.D.Director Artificial Lung Lab, MIRM
• Brian FrankowskiDesigner, Artificial Lung Lab, MIRM
• Heidi EashLab Manager, Artificial Lung Lab, MIRM