HEATING CIRCUIT AND METHOD FOR INTRAVENOUS FLUID DELIVERY

• US 20080255538A1
• Filed: 03/12/2008
• Published: 10/16/2008
• Est. Priority Date: 03/12/2007
• Status: Abandoned Application

• Current Assignee: LMA Medical Innovations Ltd. (Teleflex Incorporated)
• Original Assignee: LMA Medical Innovations Ltd. (Teleflex Incorporated)
• Inventors: Ellis, Kent D.
• Application Number:
  US12/047,251
• Publication Number:
  US 20080255538A1
• Time in Patent Office: Days
• US Class Current: 604/507
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media

Abstract

An apparatus for warming fluids includes a heating element having a resistance value that limits an amount of heat dissipated from the heating element to a threshold temperature value in response to a specific amount of electrical energy being applied to the heating element. A fluid carrying member may have the heating element coupled thereto to transfer heat from the heating element to a fluid within the fluid carrying member. A power supply may control a temperature of the fluid so as not to exceed the threshold temperature value by applying the specific amount of electrical energy to the heating element.

Claims

1. A method of warming an intravenous fluid comprising:

attaching an electrical resistive heating element to a fluid supply line, a resistance value of the heating element being selected to limit a current through the heating element to a known value for a selected voltage; and

electrically coupling a power source to the electrical resistive heating element, the voltage of the power source having a substantially steady state value that is selected based on the resistance of the heating element, to ensure that the temperature of the heating element cannot exceed a temperature range that is above a safe value for heating the fluid to be intravenously delivered to a patient.

2. The method of claim 1 wherein attaching the electrical resistive heating element includes winding the heating element along a length of the fluid supply line.

3. The method of claim 2 wherein attaching the electrical resistive heating element includes winding a stainless steel thread along the length of the fluid supply line.

4. The method of claim 1 wherein attaching the electrical resistive heating element includes braiding the heating element along a length of the fluid supply line, the heating element encased within an insulative sleeve.

5. The method of claim 4 wherein attaching the electrical resistive heating element includes braiding a stainless steel thread along the length of the fluid supply line, the stainless steel thread encased within the insulative sleeve.

6. The method of claim 5 wherein attaching the electrical resistive heating element includes encasing the fluid supply line having the stainless steel braids thereon with a shrink wrap tubing and applying heat to seal the shrink wrap tubing around the fluid supply line and the stainless steel braids.

7. The method of claim 1, further comprising printing the heating element on an adhesive backing material layered with conductive material that serve as buss bars.

8. The method of claim 7 wherein printing the heating element on the adhesive backing material includes printing at least one of a silver ink, graphite and carbon fibers on the adhesive backing material.

9. The method of claim 7 wherein attaching the electrical resistive heating element to the fluid supply line includes adhering the adhesive backing material along a length of the fluid supply line such that the printed heating element portion of the adhesive backing material encases the fluid supply line along the length thereof.

10. The method of claim 1, further comprising the resistance value of the heating element is approximately 30Ω

.

11. The method of claim 1, further comprising limiting the current through the heating element to less than 5 amps.

12. The method of claim 10, further comprising selecting the voltage of the power source not to exceed 6V such that the temperature of the heating element does not exceed 39°

C.

13. The method of claim 1, further comprising:

attaching at least one additional resistive heating element to the fluid supply line having a same resistance as the electrical resistive heating element; and

coupling an additional power source to the additional heating element, a voltage of the additional power source having a value that does not exceed a threshold voltage to ensure that the temperature of the heating element cannot exceed a temperature range that is above a selected value relative to the target temperature of a human patient for heating the fluid to be intravenously delivered to the patient.

14. The method of claim 13, further comprising selecting the voltage of the additional power source not to exceed 6V such that the temperature of the heating element does not exceed 39°

C.

15. A method for warming fluids, the method comprising:

providing a heating element having a resistance value that limits an amount of heat dissipated from the heating element to a threshold temperature value in response to a specific electric voltage being applied to the heating element;

coupling the heating element to a fluid carrying member having fluid to be delivered into a biological interface to at least partially cause a transfer of heat from the heating element to the fluid; and

controlling a temperature of the fluid so as not to exceed the threshold temperature value by applying the specific voltage to the heating element; and

preventing the voltage of the electrical energy applied to the heating element from being exceeded.

16. The method according to claim 15 wherein the voltage is prevented from exceeding the specific value by a voltage regulator circuit.

17. The method according to claim 15 wherein a circuit breaker is provided and that will create an open circuit if the voltage is exceeded.

18. A method for intravenously feeding fluid to a patient comprising:

placing a needle into a blood vessel of a patient;

providing a flow of intravenous fluid to the needle for supply into the patients blood vessel;

heating the fluid as it flows towards the patients blood vessel; and

preventing the temperature of the heat source that provides heat to the fluid from exceeding a selected value for fluid to be supplied to a patient, by limiting the voltage that can be applied to a resistive heating element to a obtain a temperature of the fluid at or less than 40°

C. at all times.

19. An apparatus for warming fluids, the apparatus comprising:

a heating element having a resistance value that limits an amount of heat dissipated from the heating element to a threshold temperature value in response to a specific voltage being applied to the heating element;

a fluid carrying member having the heating element coupled thereto to transfer heat from the heating element to a fluid within the fluid carrying member; and

a power supply to control a temperature of the fluid the power supply limiting the maximum temperature that the fluid can achieve by limiting the voltage applied to the heating element.