System and method for leak detection in external cooling pad

• US 20070016270A1
• Filed: 07/14/2005
• Published: 01/18/2007
• Est. Priority Date: 07/14/2005
• Status: Active Grant

• Current Assignee: Zoll Circulation Incorporated (Asahi Kasei Corporation)
• Original Assignee: Zoll Circulation Incorporated (Asahi Kasei Corporation)
• Inventors: Collins, Kenneth, Palmer, Grant, Stelea, Stelica, Kimball, David, Shimada, Lynn
• Granted Patent: US 7,951,182 B2
• Time in Patent Office: Days
• US Class Current: 607/96
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00119 alarm; indicating an abnormal situation
• CPC Class Codes: A61F 2007/0001 Body part
• CPC Class Codes: A61F 2007/0054 with a closed fluid circuit, e.g. hot water
• CPC Class Codes: A61F 2007/0056 for cooling
• CPC Class Codes: A61F 7/0085 Devices for generating hot or cold treatment fluids
• CPC Class Codes: A61F 7/02 Compresses or poultices for effecting heating or cooling
• CPC Class Codes: A61F 7/10 Cooling bags, e.g. ice-bags

Abstract

An externally-applied heat exchange pad has three layers laminated together, an inner and outer non-conductive layer and a middle conductive layer. A leak in the inner layer causes coolant to contact the middle layer and change impedance, which can be sensed and used as an indication of an impending total leak of the pad,

Claims

1. A heat exchange pad configured for placement against the skin of a patient to exchange heat therewith, comprising:

an outer envelope including;

an outer layer made of a high dielectric material such that any electrical discharge in the pad is effectively blocked from passing through the outer layer to the patient;

an inner layer; and

a middle layer sandwiched between the inner and outer layers and made of a relatively electrically conductive material, the middle layer being electrically connected to a control system associated with the pad.

2. The pad of claim 1, wherein the layers are laminated together.

3. The pad of claim 1, wherein in the event of a rupture in the inner layer, coolant in the pad contacts the middle layer to establish a change in impedance that is sensed by the control system.

4. The pad of claim 3, wherein an impedance between the middle layer and the coolant is used as an indication as to whether a leak exists.

5. The pad of claim 4, wherein a drop in impedance indicates a leak in the inner layer.

6. The pad of claim 1, wherein the inner layer is made of the same material as the outer layer.

7. The pad of claim 1, wherein the middle layer is made of foil.

8. The pad of claim 1, wherein the middle layer is made of plastic impregnated with conductive material.

9. A patient temperature control system, comprising:

at least one pad positionable against the skin of a patient to exchange heat therewith;

a control system engaged with the pad to circulate coolant therethrough to establish a desired temperature; and

means on the pad for providing early warning of a complete loss of integrity of the pad before it occurs.

10. The system of claim 9, wherein the means for providing includes an envelope defined by an outer non-conducting layer, an inner non-conducting layer, and a middle conducting layer sandwiched therebetween.

11. The system of claim 10, wherein the middle layer is electrically connected to a control system associated with the pad.

12. The system of claim 10, wherein the layers are laminated together.

13. The system of claim 10, wherein in the event of a rupture in the inner layer, coolant in the pad contacts the middle layer to establish a change in impedance that is sensed by the control system.

14. The system of claim 13, wherein an impedance between the middle layer and the coolant is used as an indication as to whether a leak exists.

15. The system of claim 14, wherein a drop in impedance indicates a leak in the inner layer.

16. The system of claim 10, wherein the inner layer is made of the same material as the outer layer.

17. The system of claim 10, wherein the middle layer is made of foil.

18. The system of claim 10, wherein the middle layer is made of plastic impregnated with conductive material.

19. A method for providing an alarm indicating an impending loss of fluid integrity of a heat exchange pad engageable with the exterior of a patient before fluid in the pad leaks out of the pad onto the patient, comprising:

receiving a signal from the pad representing an impedance; and

if the signal satisfies a leakage threshold, activating an alarm.

20. The method of claim 19, wherein the impedance at least in part is related to a middle conductive layer sandwiched between two non-conductive layers of an envelope of the pad.