METHODS USING A DRAPED LIQUID WARMING DEVICE

• US 20080272199A1
• Filed: 07/07/2008
• Published: 11/06/2008
• Est. Priority Date: 08/24/2004
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: C Change Surgical LLC
• Inventors: Kammer, Patrick, Rackers, Kevin Joseph
• Granted Patent: US 7,903,957 B2
• Time in Patent Office: Days
• US Class Current: 236/1C
• CPC Class Codes: A61B 2050/0018 Electric heating
• CPC Class Codes: A61B 46/10 specially adapted for instruments, e.g. microscopes
• CPC Class Codes: G05D 23/1909 whose output amplitude can only take two discrete values
• CPC Class Codes: G05D 23/1931 to control the temperature of one space
• CPC Class Codes: G05D 23/20 with sensing elements having variation of electric or magnetic properties with change of temperature G05D23/13 takes precedence
• CPC Class Codes: G05D 23/22 the sensing element being a thermocouple

Abstract

A liquid warming device for heating sterile fluids in a removable basin is described with emphasis on the properties of the basin interaction with the liquid warming device and with a drape that works with the basin to maintain a sterile field above the drape and the top of the basin. The interactions between a temperature sensor and a temperature well integrated in the removable basin are disclosed. Also disclosed are various desirable aspects for a control system for a liquid warming device.

Claims

1. A method of maintaining a sterile liquid near a target temperature using a liquid warming device, the method comprising the steps of:

placing a surgical drape with an opening over a cavity in the liquid warming device, the opening having a perimeter;

placing a portion of a sterile removable basin in the cavity, an exterior of the sterile removable basin in contact with the perimeter of the opening in the surgical drape such that a portion of the sterile removable basin extending into the cavity through the opening of the surgical drape is placed into thermal contact with a temperature sensing device, the combination of the surgical drape and the sterile removable basin forming a sterile barrier for at least a top surface of the liquid warming device;

placing a sterile liquid in the sterile removable basin;

providing an indication of the temperature sensed by the temperature sensing device to a fluid temperature controller;

controlling a heater to provide thermal energy to a portion of the sterile removable basin where a least a portion of the thermal energy travels through a path from the heater to the sterile removable basin that does not include the surgical drape; and

the heater controlled to avoid applying additional thermal energy when the indication of the temperature sensed by the temperature sensing device exceeds a desired indication of temperature so that the sterile liquid is maintained near the target temperature.

2. The method of claim 1 wherein the sterile removable basin includes a rim that is connected to an open end of the basin and extends over a portion of the surgical drape as part of the combination of the surgical drape and the sterile removable basin forming the sterile barrier for at least the top surface of the liquid warming device.

3. The method of claim 1 wherein the surgical drape is bonded to the exterior of the sterile removable basin such that the steps of placing the surgical drape with the opening over the cavity in the liquid warming device and placing the sterile removable basin in the cavity are accomplished together.

4. The method of claim 1 wherein the step of placing the surgical drape with an opening over the cavity in the liquid warming device includes attaching the surgical drape to the liquid warming device before the insertion of the portion of the sterile removable basin through the opening in the surgical drape and into the cavity.

5. The method of claim 4 wherein the surgical drape is attached to a portion of the top surface that defines the cavity.

6. The method of claim 1 wherein the surgical drape is stretched by the insertion of the sterile removable basin through the opening in the surgical drape to form an interference fit so that the sterile removable basin and surgical drape can be lifted without the surgical drape falling off the sterile removable basin.

7. The method of claim 6 wherein the insertion of the sterile removable basin through the opening in the surgical drape is performed before placing the sterile removable basin in the cavity such that the steps of placing the surgical drape with the opening over the cavity in the liquid warming device and placing the sterile removable basin in the cavity are accomplished together.

8. The method of claim 1 wherein the portion of the sterile removable basin extends through the opening in the surgical drape to move a spring loaded temperature sensing device.

9. The method of claim 1 wherein the placement of the surgical drape over the liquid warming device covers a set of at least one indicator light that can be seen through the surgical drape to indicate that the sterile fluid is near the target temperature.

10. The method of claim 1 wherein a user can provide the target temperature to the liquid warming device.

11. The method of claim 1 wherein the step of controlling the heater to provide thermal energy to the portion of the sterile removable basin includes measuring a temperature of the heater and controlling the heater to converge on a heater set point that is a fixed value when the difference between the indication of temperature sensed by the temperature sensing device and the desired indication of temperature exceeds a first value.

12. The method of claim 11 wherein the heater set point is set using a proportional integral derivative control scheme when the temperature difference is below the first value.

13. A method of maintaining a sterile liquid near a target temperature using a liquid warming device, the method comprising the steps of:

placing a surgical drape with an opening over a cavity in the liquid warming device, the opening having a perimeter;

placing a portion of a sterile removable basin in the cavity and in contact with the perimeter of the opening in the surgical drape such that a portion of an exterior surface of the removable basin extending through the opening in the surgical drape is placed in proximity to a temperature sensing device;

placing the sterile liquid in the sterile removable basin; and

controlling a flow of thermal energy provided to the sterile liquid in order to maintain the sterile liquid near the target temperature, at least some of the thermal energy flowing to the sterile liquid passing through the portion of the exterior surface of the sterile removable basin extending through the opening in the surgical drape.

14. The method of claim 13 wherein a portion of the sterile removable basin is extended through the opening in the surgical drape before placing the surgical drape with the opening over the cavity in the liquid warming device and placing the portion of the sterile removable basin in the cavity.

15. The method of claim 13 wherein the step of placing the sterile removable basin includes aligning a portion of a bottom of the basin with a basin detector that interacts with a control system so that energy is not applied to send a flow of thermal energy when a basin is not present.

16. The method of claim 13 wherein the step of controlling the flow of thermal energy provided to the sterile liquid in order to maintain the sterile liquid near the target temperature includes controlling an amount of current provided to a set of at least one resistive heater.

17. The method of claim 13 wherein the step of controlling the flow of thermal energy provided to the sterile liquid in order to maintain the sterile liquid near the target temperature includes controlling an infra-red heat source.

18. The method of claim 13 wherein the step of controlling the flow of thermal energy provided to the sterile liquid in order to maintain the sterile liquid near the target temperature includes controlling a microwave heat source.

19. The method of claim 13 wherein the step of controlling the flow of thermal energy provided to the sterile liquid in order to maintain the sterile liquid near the target temperature includes controlling an ultrasonic heat source.

20. The method of claim 13 wherein the step of controlling the flow of thermal energy provided to the sterile liquid in order to maintain the sterile liquid near the target temperature includes controlling an induction heating heat source.