Intravenous Cooling System to Induce Mild Hypothermia

April 10th, 2007

Steve Huppman

Jermaine Johnson

Sylvia Kang

Erin Wacker

University of PittsburghSenior Design – BioE 1160-1161

Cardiac Arrests

• On average EMS treat 107,000 – 240,000 out-of-hospital cardiac arrests per year1

• Cardiac arrest with no blood flow for a period >5 min cerebral brain damage due to ischemia will occur

• In 2006, AHA estimates 163,221 out-of- hospital cardiac arrests annually in US1

1. American Heart Association. Heart Disease and Stroke Statistics – 2006 Update. www.americanheart.org 2006

Therapeutic Hypothermia

• Therapeutic hypothermia in literature since 1950’s but widely ignored until 2002

• ILCOR recommended unconscious cardiac arrest patients should be cooled between 32 – 34 °C for 12-24 hrs2

• Cooling the body to this temperature immediately after cardiac arrest has the potential improve the neurological outcome and reduce the mortality rate

2. Nolan, JP. Morley, PT. Vanden Hoek, TL, et al. Therapeutic hypothermia after cardiac arrest: an advisory statement by the advanced life support task force of the International Liaison Committee on Resuscitation. Resuscitation. Vol. 57, No. 3, 2003

Project Objectives

• Design a device to induce mild hypothermia in a person that has suffered cardiac arrest no later than 5 min after blood flow has ceased

• Will do so by designing an IV cooling system that will attach between a saline bag and the IV injection site on the patient

• Device should be able to cool saline to a temperature 10°C below room temperature for a period of 15 min

• Additional external cooling will occur as the device is placed on the chest of the patient

Picture

Intravenous Fluid

Cold Fluid to Patient

Chemical Ice-Bag with Internal Tubing

Physical and Operational Characteristics

• Able to begin the process of inducing mild hypothermia (34 -36°C)

• Disposable, portable and light weight (<2 lb.)

• Able to stay cold (<15°C) for 15 min

• Capable to function at normal room temperature (22.5°C)

• Placed on the top of the patient’s chest

Must be

Market Size

• To be used by EMS and other emergency first responders to help cardiac arrest victims

• 107,000 – 240,000 cardiac arrests treated per year out of the hospital3

• We envision the device can be used in all emergency vehicles

• May also be used to help victims suffering from heat-related illness

• Firefighters

3. American Heart Association. Heart Disease and Stroke Statistics – 2006 Update. www.americanheart.org 2006

Competitive Analysis• Celsius Control System™ by Innercool

Therapies

PortabilityAnd

Emergency

Usage

TemperatureControllability

Effectiveness

ofCooling

Price

IV CoolingSystem

√ √ √

Celsius Control

System√ √(US Patent 6096068, Innercool Therapies, Inc, 1998)

Competitive Analysis (con’t)

• Cooling Body Garment• Receives gaseous coolant from a supply

• Cooling garment applies the coolant directly to the skin of the patient

• As the coolant moves away from the patient, it carries the heat away, thereby cooling the patient

PortabilityAnd

Emergency

Usage

TemperatureControllability

Effectiveness

ofCooling

Price

IV CoolingSystem

√ √ √

Cooling BodyGarment

(US Patent 7056282, Medtronic, Inc, 2003)

Competitive Analysis (con’t)• Hypothermia Induction Device

• Recirculates blood through an extracorporeal circuit using a venous access

• The blood can be cooled and/or treated before reentry to the vascular system

PortabilityAnd

EmergencyUsage

TemperatureControllabilit

y

Effectiveness

ofCooling

Price

IV CoolingSystem

√ √ √

Hypothermia

InductionDevice

√ √

(US Patent 2006/0041217, 2006)

Marketing Suggestions

• Big market on induction of hypothermia

• Many previous methods and devices have been developed on this topic

• Focused on either precise internal cooling or external cooling only

• Portable internal cooling systems used in emergency situations have been rarely studied

Theoretical Design Considerations

• Conservation balance for mass through a tube • Test subject

• 160 pounds• 50 liters of body fluid (water)• Starting temperature of 37°C• Ending temperature of 34°C

• Ambient conditions• Room temperature of 22.5°C• Ammonium nitrate solution temperature of

4°C

• Want to infuse 2 liters• Infused saline needs to be -40°C

• Infused saline enters at 10°C• Need to infuse 6.3 liters

• This would double blood volume

*Reconsider product specifications*

Theoretical Design Considerations

Design Alternatives

• Design #1 tubing in series• Standard IV tubing

• Saline temp 14.9°C• Flow rate 0.5 ml/sec • 60 mins to infuse 2 L.

• Minivolume IV tubing• Saline temp 14.7°C• Flow rate 0.1 ml/sec • 300 mins to infuse 2 L.

Intravenous Fluid

Cold Fluid to Patient

Chemical Ice-Bag with Internal Tubing

*Insufficient cooling and flow rate*

Design Alternatives

• Design #2 tubing in parallel

32 tubes across 2 rows of 16

*Pressure drop too large*

Design Description

• Tubing in parallel

1 row of 16

• Tubing in parallel

• Standard IV tubing• Average saline temperature of 10°C

• Flow rate of 1 ml/sec 30 mins to infuse 2 L.

• Using the same mass conservation as before

• Infusing 2 liters of saline at 10°C

• Ammonium nitrate solution temp of 4°C

Design Description

*Will decrease body temp by ~1.5°C*

Engineering Technologies/Methodologies

• Manifold designed in SolidWorks

• Manufactured by hand• Manifold: Dacron (6”)• Tubes: PVC, size of

standard IV tubing(10”)• 1 Ammonium Nitrate :

2 Water*

Experimental Set Up

Saline + Pressure Bag Heat Exchanger Patient + Thermometer

Design Weaknesses

• Infusion of 2 L takes 30 mins but device is only used for 15 min

• Device needs to be primed saline bag becomes a part of the device

• Measured average temperature of water do not know temp at which saline is entering

Quality Systems Analysis

• Initial Hazard Analysis

• Regulation

Risk Classification

Risk Classification: 4 = acceptable, 1 = unacceptable

OccurrenceConsequences

Negligible Marginal Critical Catastrophic

Frequent 2 1 1 1

Probable 3 2 1 1

Occasional 3 3 2 1

Remote 4 3 3 2

Improbable 4 4 3 3

Incredible 4 4 4 4

Initial Hazard Analysis

Hazard Risk Class

Ammonium Nitrate Entering Blood Stream Due To Entry Into Saline LineIndividuals Involved:

Patient

1

Skin Irritation Due To Casing Malfunction (i.e. Tear, Leakage from Seals, etc)

Individuals Involved:Emergency Response Personnel

Patient

3

Premature Activation of Ammonium NitrateIndividuals Involved:

None

4

Regulation• Class II Medical Device C

• Predicate Devices: CFR Title 21 – 510(k)

• Cooling Systems• Subpart F – Part 870 - Cardiovascular Therapeutic Devices

• 870.5900 Thermal Regulation System Class: II

• Subpart F – Part 890 - Physical Medicine Therapeutic Devices• 880.5540 Tubing, Fluid Delivery Class: II

• Intravenous Tubing• Subpart F – Part 880 - General Medicine Devices

• 890.5710 Pack, Hot or Cold, Disposable Class: I

• 890.5720 Pack, Hot or Cold, Water Circulating Class: II

Team Member Contributions

• Erin• Theoretical design considerations

• Jermaine• Literature review, FDA regulations

• Steve• Ordering supplies, testing of prototype

• Sylvia• Marketability, competitive analysis

Acknowledgements

Thanks to• The generous gift of Drs. Hal Wrigley and

Linda Baker• Department of Bioengineering• Our mentor, Dr. James Menegazzi• Andy Holmes• Dr. Jack Patzer II• Dr. Mark Gartner

Questions?