Megan Foran, Danny Jones, & Frank MoynihanDr. Bob Wilkinson, Ph.D.
Brief Overview
Starling’s Law of the HeartPreload increases Cardiac Output
increases Transfer of blood from veins to arteries Preload decreasesNegative-feedback Loop
An increase in peripheral resistance causes an increase in preload
There is only one cardiac output that maintains constant venous return
NeedStarling’s Law can be difficult for
cardiophysiology students to visualizeTo aid comprehension, students need an
interactive learning model to supplement the lecture and reading material
The model should allow the students to control the variables of mechanical circulatory regulation:Stroke Volume, Heart Rate, and Peripheral
Resistance
Specific Design Requirements
Design SpecificationsPortable & Easy to Use
2-5 kg; 1-2 m in circumferenceRelatively Inexpensive (<$500)SustainableDiscrete structures
Left ventricle, Arteries, Veins, Resistance Vessels (Capillary Bed)
Mechanical Pump (LV), controlled by student, supplies power to the system (SV: 100-200 ml)
Design SpecificationsVeins 20-30 times more compliant than
arteriesVariable resistance in capillary bed: (0,∞)Variable fluid volume within the system: (0,3 L)Pressure drops across arteries, capillary bed,
and veins are approximately 7%, 92%, and 1% respectively (Smith, 1999)
Quantitative pressure measurements from within the system
Color gradation to illustrate oxygenation of the blood
Design Alternatives and Analysis
Elements of the Design
FluidLeft VentricleArteries and VeinsResistance VesselsVariable Resistance Mechanism
Fluid General SpecsWeightDurableSafetyLow CostAestheticsUser-FriendlyProximity to Actual Blood
DensityEase for Quantitative
Measurements
Fluid IdeasWaterCompressed AirJuiceAqueous Glycol (1)Vegetable OilMouthwash (2)
(1)
(2)
Fluid Preliminary Pugh Chart
Compressed Air Water Aqueous Glycol MouthwashWeight 7 Less than 5 kg 10 8 8 8
Durability 10 Sustainable 7 8 8 7Safety 10 Safe for novice user 10 10 10 9Cost 8 Less than $500 10 10 10 7
Aesthetics 6Relative Likeness to
Physiology7 10 10 10
User-Friendly 10Accessible to those without technical
background10 10 10 10
462 476 476 432
Criteria Weight Requirement
Total
Fluid
In-Depth Analysis: FluidWater
Cheap and PlentifulDensity: 1.00 g/cubic cmSafe and User FriendlyDurableEases Measurements
Aqueous GlycolRelatively CheapDensity: 1.04 g/cubic cmSafe and User FriendlyDurableEases Measurements
Fluid Final Pugh Chart
Water Aqueous GlycolProximity to Actual
Blood Density9 Less than 5 kg 7 9
Durability 10 Sustainable 10 10Safety 10 Safe for novice user 10 10Cost 8 Less than $500 10 8
User-friendly 10
Accessible to students without a
technical background
10 10
Aesthetics 6Availablility of
connections, valves, and drain
10 10
503 505
FluidCriterion Weight Requirement
Total
Left Ventricle General SpecsLightweightDurableLow cost Mechanical InputSafetyAestheticsCompact SizeFeasibility of
Quantitative Measurements/Output
Left Ventricle IdeasManual Resuscitation
Bag (1)
Punching Bag Balloon
Thin-Walled Elastomer Core (2)
PVC Blowing Balloon (3)
Water Pump
(1)
(2)
(3)
Left Ventricle IdeasWater Dispenser Jug (1)
Plastic Water Bottle
Large Medical Balloons (2)
Humidifier Water Chamber (3)
Fuel Line Primer Bulb (4)
(1)
(2)
(3)
(4)
Left Ventricle Preliminary Pugh ChartResuscitation Bag Elastomer Core PVC Balloon Water Pump Medical Balloons Water Chamber Primer Bulb
Power 9 Mechanical 10 9 9 2 7 2 10Weight 7 Less than 5 kg 8 8 9 4 9 4 9
Size 7 Less than 4 sqft 10 6 6 7 6 8 9Durability 10 Sustainable 4 7 7 10 7 10 8
Safety 10 Safe to novice user 9 9 8 10 10 9 9Cost 8 Less than $500 10 8 9 5 7 7 9
Output 9 Stroke Volume 10 5 6 10 7 9 8
Aesthetics 6Relative Likeness
to Physiology8 7 6 6 9 3 8
Feasibility of Quantitative
Measurements9
Pressure and Volume
Measurements3 2 2 9 3 9 3
User-Friendly 10Accessible to those without technical
background9 8 8 3 5 5 9
"Compliance" 10
Can achieve veins 24x more
compliant than arteries
- - - - - - -
Fittings 9Availablility of connections,
valves, and drain- - - - - - -
681 588 596 572 588 578 695Total
Weight RequirementCriteriaLeft Ventricle
In-Depth Analysis: Left Ventricle
Reusable Manual Resuscitation BagDurable; $1501500 mL; 0.4 kgUsed with air; Volume
MeasurementsPVC Blowing Balloon
Eliminated due to durability, size, and single opening
Fuel Line Primer Bulb (5/16”)Durable; $15-$201000 mLUsed with aqueous solutionEnd Connections
Left Ventricle Final Pugh Chart
Reusable Resuscitation Bag Fuel Line Primer BulbPower 9 Mechanical 10 10Weight 7 Less than 5 kg 9 9
Size 7 Less than 4 sqft 9 10Durability 10 Sustainable 8 8
Safety 10 Safe to novice user 10 10Cost 8 Less than $500 7 10
Output 9 Stroke Volume 10 5
Aesthetics 6Relative Likeness
to Physiology7 9
Feasibility of Quantitative Measurements
9Pressure and
Volume Measurements
3 5
User-Friendly 10Accessible to those without technical
background10 10
End Connections 8
Aesthetics and perceived ease of
connection to veins and arteries
6 9
Compatibility with Aqueous Liquid 9 - 2 10777 889
Left Ventricle
Total
Weight RequirementCriteria
Arteries and Veins General Specs
Compact SizeLight WeightDurableAestheticsFeasibility of
Quantitative Measurements
ComplianceConnections
Arteries and Veins Ideas
Balloons
Tubing
Chambers
In-Depth Analysis: Arteries and Veins
Latex BalloonsVery cheap; Size and WeightQualitative complianceNot Durable
Urethane BalloonsIncreased Durability; Variable
ComplianceMore expensive and too large
Latex Rubber TubingNot Durable (<1 year)Variable Compliance
In-Depth Analysis: Arteries and Veins
Polyethylene TubingLess compliant than latexMore durable than latexEquivalent in Cost
ChambersSustainable; Bulky/Not
AestheticQuantitative ComplianceObservable Volume ChangeHigher Cost with plugs, etc.
Arteries and Veins Pugh Chart
Resistance Vessels General SpecsLight WeightCompact SizeLow Rigidity (able to
bend)DurableSafetyLow CostFittings
Resistance Vessels Pugh Chart
Nylon Tubing
Rubber Tubing
Vinyl Tubing
PVC Piping
Metal Piping
Weight 3 Less than 5 kg 10 10 10 7 3Size 3 Less than 4 sqft 10 10 10 9 7
Rigidity 7 Low Rigidity 3 8 1 0 0Durability 9 Sustainable 9 7 9 10 10
Safety 9 Safe to Novice User 10 10 10 10 10Cost 5 Less than $500 10 10 10 8 6
Fittings 9Availability of
Connections, Valves, and Drains
9 2 9 6 7
383 337 369 322 303
Criterion Weight RequirementsResistance Vessels
Total
* Resistance Mechanism would decide final decision (Valves, Clamps, or Resistance Tubes)
Resistance Mechanism General SpecsSimplicityWeightSizeDurabilityCostResistance RangeUser FriendlyAestheticsAvailability of Fittings
Resistance Vessels Pugh Chart
* Resistance Vessels are thus nylon tubes due to the plethora of valve connector options
Clamps Valves Resistance TubesSimplicity 10 Simple Mechanism 10 10 3
Weight 2 Less than 5 kg 10 10 7Size 4 Less than 4 sqft 10 8 7
Durability 3 Sustainable 10 10 10Safety 10 Safe for novice user 9 9 7Cost 5 Less than $500 9 7 6
Resistance Range
9 0 to ? 8 9 7
Aesthetics 6Relative Likeness to
Physiology3 7 5
User-Friendly 10 Easy to Operate 9 10 4
Fittings 7Availability of Connections,
Valves, and Drains0 8 10
405 486 375
Resistance MechanismCriteria Weight Requirement
Total
Chosen Design
Rough Diagram of Chosen Design
Analyses Needed to Complete Design
Best Ways to Secure Connections
Devise Method for determining Stroke Volume
Pressure Measurements via Chambers
Calculating Desired Length and Diameter of Vessels in Periphery
Best Method to Vary Pressure in Chambers to Simulate Compliance
Optional: Color Gradation
Team Organization
Project Schedule
Task 3-Sep 10-Sep 17-Sep 24-Sep 1-Oct 8-Oct 15-Oct 22-Oct 29-Oct 5-Nov 12-Nov 19-Nov 26-Nov 3-Dec 10-Dec
Project Selection
Project Scope
Recognition of Need
Become Informed
Develop Project Specifications
Preliminary Report
Create Web Page
Concept Generation
Concept Selection
Progress Report
Embodiment & Optimization
Evaluation
Final Report
Poster Competition
In Progress Deadl ine
Organization of Responsibilities
Team Teaching Heart• Meet Weekly• Compile Weekly Reports• Prepare Written Reports
Megan • Preliminary
Presentation• Project
Management• Pressure
Measurements
Danny• Progress
Presentation• WebMaster• Volume
Measurements
Frank• Final
Presentation• DesignSafe
Report• Vessels
(Connections and Dimensions)
Works Cited "Hygenic Rubber Latex Tubing." Medical Supplies - Discount Medical Supplies and
Equipment at JRSmedical.com. JRS Medical, n.d. Web. 16 Oct. 2012.<http://www.jrsmedical.com/>.
"Latex Tubing - Frequently Asked Questions." Natural Rubber Latex Tubing. Web. 16 Oct. 2012. <http://www.kentelastomer.com/latex-tubing-faq>.
"Sustainability." Polyurethanes. American Chemistry Council, n.d. Web. 17 Oct. 2012. <http://polyurethane.americanchemistry.com/>.
"Primer Bulb." EPA Certified S : Attwood Marine. Attwood Marine Products, 2012. Web. 21 Oct. 2012. <http://www.attwoodmarine.com/store/product/epa-certified-primer-bulb>.
"Resuscitation Bags." Resuscitation Bags. Ventlab Corporation, 2003. Web. 21 Oct. 2012. <http://www.ventlab.com/Resuscitation.htm>.
Smith, A. M. "A Model Circulatory System for Use in Undergraduate Physiology Laboratories." Advances in Physiology Education 22.1 (1999): S92-99. PubMED. Web. 16 Sept. 2012.
Timms, Daniel, Mark Hayne, Keith McNeil, and Andrew Galbraith. "A Complete Mock Circulation Loop for the Evaluation of Left, Right, and Biventricular Assist Devices." Artificial Organ 29.7 (2005): 564-72. Queensland University of Technology. Web. 15 Sept. 2012.
US Plastic. Web. 8 Oct. 2012. <www.usplastic.com>.
Questions?