Download Swan-Ganz catheter use

Developing a
Cardiovascular Model
James Clear
Chase Houghton
Meghan Murphy
Problem Statement
• No all-purpose cardiovascular model is
currently commercially available.
– Models are made for testing of a particular device
exclusively
– No in vitro model exists for physicians to learn and
visualize cardiac procedures
• Current model exists from last semester but
has design flaws and performance
shortcomings
Problem Statement:
Current Devices
• Patented model for fatigue testing of prosthetic tricuspid
valve replacements. Model applies pressure on valve to
mimic in vivo forward and backflow gradients.
• Agar gel model with characteristics of biological tissue used
to model left ventricular and aortic chambers. Ultrasound
imaged flow dynamics through bicuspid valve.
• Model testing ventricle assist devices pumping
performance and quantifying flow dynamics. Resistance
comparable to native heart present.
• Patented teaching model for complex cardiac surgery
including repair of congenital heart defects. Clay open
system model with detachable colored tubes.
Previous Design
Emptied by lifting
model
Leaking joints
Anatomically
incorrect heart
Size and weight
of base- not
portable
Design flaws to be addressed:
Not easily drained, model leaks, heart itself is not anatomically correct, not
portable, no flow gradient
Primary Objective
It is the purpose of this team to use the
previously established model as a foundation
for developing a heart model of the inferior
venous flow for testing intracardiac
procedures including stent and catheter
delivery.
Specific Device Objectives
• Our device has been designed to:
• Demonstrate catheters used as optical scopes in the
heart
– Proof of concept for this scope device for potential investors
• Demonstrate Swan-Ganz catheters used to measure
blood pressure in the heart
– Perform right heart catheterization- measure pressures in the
heart
• Demonstrate catheter delivery to intended site using
sail on catheter tip
– Illustrated in model by water flow under pump generated
pressure gradient
Solution Description:
Adaptations to Current Design
• Remove upper half – decrease size, increase
portability
• Connect metering bellows pump to simulate
blood flow through veins
– Flow rate: 1.6 L/min
– Pressure gradient: .2 psi
• Acrylic tubing – can withstand high impact stress,
high clarity
• Acrylic dichloroethylene glue – welding joints
• Multiple catheter access points– for entry of
catheter and prevent back flow, collecting basin
for any water loss
Adapting Current Model
Device Functions and Specs
• Visualize catheter movement through device
– high clarity acrylic tubing
• Water tight venous system
– acrylic dicholoethylene glue
• Anatomically correct venous flow
– Metering bellows pump-:.2 psi, 1.6 L/min
• Anatomically correct heart
– Casted with clear flexible urethane
• Fit inside carry on luggage
– 22” x 14” x 9”
Model Design
www.cvcu.com.au/images/cv_torso.jpg
Progress & Future Direction
• Make final 180 degree
turns
• Manufacture modular Yshaped connector with
O-rings
• Explore casting with
polyester resin to
improve clarity
• Attempt manufacturing
bored acrylic 4in sphere
2.5 in bend
diameter
4 in
Heart Model Directions
Bored Acrylic Sphere Concept:
v= ~30ml
~4 in diameter sphere
v= ~90ml
Casting Acrylic Mold Attempt:
Validation
• Performance will be assessed by how physicians
interface with device and how realistically the
device models cardiac procedures
• Conclusions will be drawn on how the design
implements intended design features
– Portable, Transparent, Pump, Water-tight
• Physician input will be considered for future
design improvements and used to identify
drawbacks
Physician Specific Validation
• Does the model visibly demonstrate optical scope
catheter use into the heart?
• Does the model demonstrate Swan-Ganz catheter
use in the heart?
– Is it possible to measure pressures in the heart (perform
right heart catheterization)?
• When catheter delivery is demonstrated, is it clear to
observers what structures the model replicates?
References
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Appartus for Testing Prosthetic Heart Valve Hinge Mechanism. More RB et al.,
inventors. United States Patent US5531094.
http://www.freepatentsonline.com/5531094.pdf accessed 12 Nov 2009.
Durand LG, Garcia D, Sakr F, et al. A New Flow Model for Doppler Ultrasound Study
of Prosthetic Heart Valves. Journal of Heart Valve Disease. [Internet] 2006 Nov 4
[cited 12 November 2009]; 17. Available from: http://www.icr-heart.com/journal/.
Hertzberg BS, Kliewer Ma, Delong DM et al. Sonographic Assessment of Lower
Limb Vein Diameters: Implications for the Diagnosis and Characterization of Deep
Venous Thrombosis. AJR. May 1997; 168:1253-1257.
Pantalos GM, Koenig SC, Gillar KJ, Giridharan GA, Ewert DL. Characterization of an
adult mock circulation for testing cardiac support devices. ASAIO. Feb 2004;
50(1):37-46.
Pediatric congenital heart defect model. United States Patent US7083418.
http://www.patentstorm.us/patents/7083418/description.html accessed 12 Nov
2009.
Replogle RL, Meiselman HJ, Merrill EW et al. Clinical Implications of Blood
Rheology Studies. Circulation 1967; 36:148-160.