Control of vacuum level rate of change

• US 7,022,113 B2
• Filed: 07/11/2002
• Issued: 04/04/2006
• Est. Priority Date: 07/12/2001
• Status: Expired due to Term

• Current Assignee: KCI Licensing Incorporated (3M Company)
• Original Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Inventors: Risk, James Robert Jr., Lockwood, Jeffrey S., Petrosenko, Robert
• Primary Examiner(s): Zalukaeva, Tatyana
• Assistant Examiner(s): Bogart, Michael G.
• Application Number:
  US10/192,894
• Publication Number:
  US 20030014022A1
• Time in Patent Office: 1,363 Days
• Field of Search: 604/289, 604/304, 604/313, 604315-319, 604/327, 604/543, 604/320, 604/355, 604/356, 601 6- 14, 602/41, 417/43, 417/44.2
• US Class Current: 604/313
• CPC Class Codes: A61M 1/732 Visual indicating means for vacuum pressure
• CPC Class Codes: A61M 1/74 Suction control underwater drainage A61M1/61
• CPC Class Codes: A61M 1/743 by changing the cross-section of the line, e.g. flow regulating valves A61M1/7413 takes precedence
• CPC Class Codes: A61M 1/85 with gas or fluid supply means, e.g. for supplying rinsing fluids or anticoagulants for negative pressure wound therapy A61M1/92, A61M1/94; combined with tracheal tubes A61M16/0463; dental instruments with combined rinsing and aspirating A61C17/0208
• CPC Class Codes: A61M 1/96 Suction control thereof
• CPC Class Codes: A61M 1/98 Containers specifically adapted for negative pressure wound therapy
• CPC Class Codes: A61M 1/982 with means for detecting level of collected exudate
• CPC Class Codes: A61M 2205/215 Tilt detection, e.g. for warning or shut-off
• CPC Class Codes: A61M 27/00 Drainage appliance for wounds or the like , i.e. wound drains, implanted drains negative pressure wound therapy devices A61M1/90; implements for holding wound open A61B17/02 ; middle ear drainage A61F11/202

Abstract

A wound treatment apparatus has a vacuum bandage covering a wound of a patient, a vacuum source coupled to the vacuum bandage, and a controller that operates the vacuum source to apply negative pressure to the wound through the bandage in a controlled manner. The controller is programmed to limit the rate of change of the negative pressure applied to the wound. A caregiver has the ability to change one or more negative pressure setpoint values and the controller of the wound treatment apparatus controls the rate of change of the negative pressure to reduce patient discomfort.

Claims

1. A vacuum wound therapy device for providing a negative pressure at a wound bed, the vacuum wound therapy device comprising:

a vacuum bandage configured to fluidly communicate with the wound bed,

a vacuum source fluidly coupled to the vacuum bandage to provide negative pressure for presentation at the wound bed, and

a controller controlling the time rate of change of negative pressure presented at the wound bed to be less than a predetermined maximum allowable rate.

2. The device of claim 1 and further comprising an electrically actuated valve electrically coupled to the controller and fluidly coupled between the vacuum source and the vacuum bandage.

3. The device of claim 2 wherein the controller generates a modulated signal.

4. The device of claim 2 and further comprising a pressure transducer in fluid communication with the wound bed and electrically coupled to the controller.

5. The device of claim 1:

wherein the controller implements a proportional, integral derivative (PID) control algorithm.

6. The vacuum wound therapy device of claim 1, wherein the controller comprises:

a regulator configured to regulate the negative pressure provided at the wound bed by the vacuum bandage and vacuum source in response to a pressure regulation signal,

a pressure transducer positioned to detect the negative pressure at the wound bed and provide a pressure signal indicative of the negative pressure at the wound bed,

setpoint circuitry configured to provide a setpoint signal indicative of a desired negative pressure at the wound bed, and

control circuitry electrically coupled to the pressure transducer, the setpoint circuitry and the regulator,

the control circuitry being configured to generate the pressure regulation signal in response to the pressure signal and setpoint signal to limit the time rate of change of negative pressure at the wound bed while adjusting the negative pressure at the wound bed to the desired negative pressure.

7. The vacuum wound therapy device of claim 6 wherein the setpoint circuitry is manually adjustable by a caregiver.

8. The vacuum wound therapy device of claim 6 wherein the regulator comprises an electrically actuated valve fluidly coupled to the bandage and the vacuum source and electrically coupled to the control circuitry.

9. The device of claim 4, wherein the pressure transducer in fluid communication with the wound bed and electrically coupled to the controller is positioned in the fluid path between the vacuum source and the wound bed.

10. The device of claim 9, further comprising a vacuum canister,

wherein the vacuum canister is positioned in the fluid path between the wound bed and the pressure transducer.

11. A vacuum wound therapy device for providing a negative pressure at a wound bed, the vacuum wound therapy device comprising:

a vacuum bandage configured to fluidly communicate with the wound bed,

a vacuum source fluidly coupled to the vacuum bandage to provide negative pressure for presentation at the wound bed,

a controller controlling the rate of change of negative pressure presented at the wound bed,

an electrically actuated valve electrically coupled to the controller and fluidly coupled between the vacuum source and the vacuum bandage, and

a pressure transducer in fluid communication with the wound bed and electrically coupled to the controller,

wherein the controller implements a proportional, integral derivative (PID) control algorithm and a filter to limit the control signal generated by the PID control algorithm within bounds.

12. A controller for regulating a negative pressure provided to a wound bed of a patient through a vacuum bandage fluidly coupled to a vacuum source, the controller comprising:

a regulator configured to regulate the negative pressure provided at the wound bed by the vacuum bandage and vacuum source in response to a pressure regulation signal,

a pressure transducer positioned to detect the negative pressure at the wound bed and provide a pressure signal indicative of the negative pressure at the wound bed,

setpoint circuitry configured to provide a setpoint signal indicative of a desired negative pressure at the wound bed, and

control circuitry electrically coupled to the pressure transducer, the setpoint circuitry and the regulator,

whereby the control circuitry generates the pressure regulation signal in response to the pressure signal and setpoint signal to limit the time rate of change of negative pressure to a predetermined maximum allowable rate at the wound bed while adjusting the negative pressure at the wound bed to the desired negative pressure,

wherein the regulator comprises an electrically actuated valve fluidly coupled to the bandage and the vacuum source and electrically coupled to the control circuitry, and

wherein the valve is a proportional yalve.

13. The controller of claim 12 wherein the control circuitry generates a modulated signal to control the valve.

14. The regulator of claim 12, wherein the proportional valve is actuated by the control circuitry to a number of positions between a fully opened position and a fully closed position.

15. A method of providing vacuum wound therapy to a wound bed comprising the steps of providing a vacuum bandage in fluid communication with the wound bed, adjusting the air pressure at the wound bed through the vacuum bandage, and controlling the time rate of change of the air pressure at the wound bed to be less than a predetermined maximum allowable rate.

16. The method of claim 15 further comprising the step of measuring the air pressure at the wound bed.

17. The method of claim 16 further comprising the step of providing a desired air pressure at the wound bed and wherein the controlling step includes adjusting the air pressure at the wound bed until the measured air pressure approximates the desired air pressure.

18. A method for applying a vacuum to a space above an open wound bed, thereby to enhance the rate of healing of the wound, the method comprising:

establishing a predetermined vacuum pressure level to be achieved in the space,

applying a suction from a vacuum source to the space, the suction being applied through a proportional valve, and

controlling the proportional valve in incremental steps to increase the vacuum up to the predetermined pressure.

19. The method of applying a vacuum of claim 18, wherein application of the suction from a vacuum source to the space is further applied through a vacuum canister positioned between the wound bed and the vacuum source

20. The method of applying a vacuum of claim 19, further comprising the step of monitoring of the vacuum pressure through pressure sensor positioned between the vacuum source and the vacuum canister.