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?