1. Heated Lavage Joe McFerron, Justin Miller, and Ashley Danicic Dr. Dinakar Golla, M.D Linda Huckenstein, R.N

2. Background Information Lavages are most frequently used to remove debris from an organ or cavity with repeated injections of a solution. Lavages are most frequently used to remove debris from an organ or cavity with repeated injections of a solution. The solution (saline) is often heated The solution (saline) is often heated to increase circulation to the area to increase circulation to the area reduce the risk of infection reduce the risk of infection and to increase the comfort of the patient and to increase the comfort of the patient

3. Methods Heat Exchanger Heat Exchanger Bulky Bulky More expensive More expensive Must rely on internal pump in the heat exchanger to propel the solution to the lavage device. Must rely on internal pump in the heat exchanger to propel the solution to the lavage device. Microwave Microwave cannot control the temperature of solution PVC IV bag deforms at 135-180 degrees F Solution immediately begins to cool, must be reheated again

4. Group Goals To design a device that when mounted onto the IV bag, can control and measure the temperature of the solution To design a device that when mounted onto the IV bag, can control and measure the temperature of the solution Heater must heat solution to desired temperature, it must be flexible, small, and capable of heating solution quickly Heater must heat solution to desired temperature, it must be flexible, small, and capable of heating solution quickly Choose insulation for heater which is resistant to chemicals, water, and other liquids. Choose insulation for heater which is resistant to chemicals, water, and other liquids. The thermocouple The thermocouple must be small enough to fit into one of the IV’s ports. must be small enough to fit into one of the IV’s ports. (~0.24 in), capable of immersion in fluids, but also must not let solution leak from port. capable of immersion in fluids, but also must not let solution leak from port. Fast and accurate response Fast and accurate response hermetically sealed hermetically sealed

5. Individual Goals Research heater options Research heater options Etched Foil-etched foil resistive element Etched Foil-etched foil resistive element Pros: more economical in small heaters, thin, very flexible, transfer heat more efficiently over larger surface area, heaters stay cooler to the touch, run higher wattages, insulation life is 10x greater, uniform heat patterns, Pros: more economical in small heaters, thin, very flexible, transfer heat more efficiently over larger surface area, heaters stay cooler to the touch, run higher wattages, insulation life is 10x greater, uniform heat patterns, Cons: heating element less durable, not as economical if manufactured Cons: heating element less durable, not as economical if manufactured Resistance Wire- wire elements, Resistance Wire- wire elements, Pros: more economical in large sizes/ manufacturing, durable, lower leakage current, withstand repeated flexing, uniform heat patterns Pros: more economical in large sizes/ manufacturing, durable, lower leakage current, withstand repeated flexing, uniform heat patterns Cons: thick, reduced watt densities Cons: thick, reduced watt densities Research insulation options Research insulation options Kapton Kapton Silicone Rubber Silicone Rubber All-Polyimide (AP) All-Polyimide (AP) Mica Mica Update Design history file Update Design history file

6. Achievements to Date Procured 2 lavages for testing Procured 2 lavages for testing Designed heater Designed heater determined approximate heater size, temperature range, Max. resistance density, power, lead locations and size determined approximate heater size, temperature range, Max. resistance density, power, lead locations and size Heater will be galvanized to mating parts. Heater will be galvanized to mating parts. 5 minute warm up time 5 minute warm up time Heater wraps around circumference of IV bag and clamped into place. Heater wraps around circumference of IV bag and clamped into place. Contacted several custom heater manufacturers Contacted several custom heater manufacturers Considering thermocouple Considering thermocouple Selected Kapton insulator Selected Kapton insulator Excellent dielectric strength, resistant to most acids, solvents, and bases, can be made for immersion in fluids. Excellent dielectric strength, resistant to most acids, solvents, and bases, can be made for immersion in fluids.

7. Completed heater design Maximum heater thickness (with foil backing): Maximum heater thickness (with foil backing): Over element: 0.4 mm Over element: 0.4 mm Over Leads: 1.4 mm Over Leads: 1.4 mm Kapton Insulator: Kapton Insulator: 0.03-0.05 mm 0.03-0.05 mm Temperature range Temperature range (-200 C -200 C) Lead Wires: Lead Wires: 0.141 mm^2

9. Work to Do Finite Element Analysis on Heater in CosmosFloWorks Finite Element Analysis on Heater in CosmosFloWorks (This week) (This week) Decide on Thermocouple Decide on Thermocouple (Mid February) (Mid February) Decide temperature controller Decide temperature controller (Mid February) (Mid February) Order heater and thermocouple prototypes. Order heater and thermocouple prototypes. (February) (February) Test these protypes Test these protypes (March-April) (March-April)

10. Criteria For Heater Success Heater heats solution to specific temperature Heater heats solution to specific temperature Heater stays securely on IV bag Heater stays securely on IV bag Completed device is easy to mount onto bag Completed device is easy to mount onto bag Heater is portable, small, and flexible Heater is portable, small, and flexible

12. Sample Calculations Warm up Power: Warm up Power: P(watts)=mCp(tf-Ti) / t P(watts)=mCp(tf-Ti) / t 1000(g)*4.19(J*g/C)*(40 C-25 C) / (600s)= 104.75 1000(g)*4.19(J*g/C)*(40 C-25 C) / (600s)= 104.75 125.7 W with heat loss 125.7 W with heat loss Conduction Loss: Conduction Loss: Pcd=KA(Tf-Ta) / 3.412*L Pcd=KA(Tf-Ta) / 3.412*L 4.08 Btu*in/ft^2/F/hr*(12.9 ft^2)*(104F -77F) / 3.412*15.24 in=27.33W 4.08 Btu*in/ft^2/F/hr*(12.9 ft^2)*(104F -77F) / 3.412*15.24 in=27.33W Radiation Loss: Radiation Loss: Pr= E*A(0.173x10^(-8))*(Tfr^2-Tar^4) / 3.412 Pr= E*A(0.173x10^(-8))*(Tfr^2-Tar^4) / 3.412 0.98(.1713*10^(-8))*((104+460)^4-(77+460)^4) / 3.412 = 8.87 W 0.98(.1713*10^(-8))*((104+460)^4-(77+460)^4) / 3.412 = 8.87 W