Method for providing negative pressure to a negative pressure wound therapy bandage

• US 10,300,178 B2
• Filed: 06/11/2015
• Issued: 05/28/2019
• Est. Priority Date: 05/26/2011
• Status: Active Grant

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Buan, John, Willems, Richard
• Primary Examiner(s): Weng, Kai H
• Application Number:
  US14/737,387
• Publication Number:
  US 20150352267A1
• Time in Patent Office: 1,447 Days
• CPC Class Codes: A61F 13/05 specially adapted for use with sub-pressure or over-pressure therapy, wound drainage or wound irrigation, e.g. for use with negative-pressure wound therapy [NPWT]
• CPC Class Codes: A61F 2013/00174 possibility of applying pressure
• CPC Class Codes: A61F 2013/00536 for draining or irrigating wounds
• CPC Class Codes: A61M 1/74 Suction control underwater drainage A61M1/61
• CPC Class Codes: A61M 1/75 Intermittent or pulsating suction A61M1/63, A61M1/772 take precedence
• CPC Class Codes: A61M 1/96 Suction control thereof
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2210/04 Skin
• CPC Class Codes: A61P 17/02 for treating wounds, ulcers, burns, scars, keloids, or the like

Abstract

A method for providing a negative pressure wherein a pump is cycled on and off to achieve a target negative pressure, which is set slightly lower than the therapeutic negative pressure. A device determines the actual pressure by averaging samples which may occur at a different rate than the pump cycle.

Claims

1. A method of providing negative pressure wound therapy comprising:

determining a therapeutic negative pressure for a negative pressure wound therapy device having a source of negative pressure, wherein the negative pressure wound therapy device is configured to be fluidically connected to a wound covered by a wound dressing;

attaining the therapeutic negative pressure under the wound dressing by activating the source of negative pressure, measuring wound pressure under the wound dressing at a first sampling rate, and determining based on the measured wound pressure that the therapeutic negative pressure is reached and thereafter deactivating the source of negative pressure; and

maintaining the therapeutic negative pressure under the wound dressing by alternately activating and deactivating the source of negative pressure based on measuring the wound pressure under the wound dressing at a second sampling rate lower than the first sampling rate, the maintaining comprising activating the source of negative pressure in response to determining that the wound pressure is more positive than the therapeutic negative pressure and deactivating the source of negative pressure in response to determining that the wound pressure reaches the therapeutic negative pressure.

2. The method of claim 1, wherein maintaining the therapeutic negative pressure comprises keeping the pressure under the wound dressing within ±

10% of the therapeutic negative pressure by alternately activating and deactivating the source of negative pressure.

3. The method of claim 1, wherein alternately activating and deactivating the source of negative pressure comprises one or more activations and one or more corresponding deactivations during a period of time, the period of time beginning when the source of negative pressure is first deactivated after the therapeutic negative pressure has been attained.

4. The method of claim 1, wherein attaining the therapeutic negative pressure under the wound dressing comprises activating the source of negative pressure until an average pressure under the wound dressing reaches the therapeutic negative pressure and thereafter deactivating the source of negative pressure, the average pressure being determined by:

measuring a plurality of pressures under the wound dressing, and

averaging the plurality of measured pressures.

5. The method of claim 4, wherein attaining the therapeutic negative pressure under the wound dressing comprises comparing the average pressure to the therapeutic negative pressure.

6. The method of claim 4, wherein maintaining the therapeutic negative pressure under the wound dressing comprises maintaining the average pressure under the wound dressing.

7. The method of claim 6, wherein maintaining the average pressure under the wound dressing comprises keeping the average pressure under the wound dressing within ±

10% of the therapeutic negative pressure.

8. The method of claim 1, further comprising:

detecting a presence of a leak while maintaining the therapeutic negative pressure under the wound dressing by determining that the source of negative pressure has been activated more than a threshold number of activations over a time interval; and

indicating the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

9. The method of claim 8, wherein the threshold number of activations is 20 activations.

10. The method of claim 1, further comprising:

detecting a presence of a leak when the source of negative pressure is activated for a threshold activation duration; and

indicating the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

11. The method of claim 1, wherein the therapeutic negative pressure is configured to range from about −

40 mmHg to about −

125 mmHg.

12. A method of providing negative pressure wound therapy comprising:

determining a therapeutic negative pressure for a negative pressure wound therapy device having a source of negative pressure, wherein the negative pressure wound therapy device is configured to be fluidically connected to a wound covered by a wound dressing;

measuring a plurality of pressures under the wound dressing;

averaging the plurality of measured pressures;

activating the source of negative pressure, measuring wound pressure under the wound dressing at a first sampling rate, and determining based on the measured wound pressure that the average pressure under the dressing achieves the therapeutic negative pressure, and thereafter deactivating the source of negative pressure; and

maintaining the average pressure under the dressing to within ±

10% of the therapeutic negative pressure by alternately activating and deactivating the source of negative pressure based on measuring the wound pressure under the wound dressing at a second sampling rate lower than the first sampling rate, the maintaining comprising activating the source of negative pressure in response to determining that the wound pressure is more positive than the therapeutic negative pressure and deactivating the source of negative pressure in response to determining that the wound pressure reaches the therapeutic negative pressure.

13. The method of claim 12, further comprising:

detecting a presence of a leak while maintaining the average pressure under the dressing by determining that the source of negative pressure has been activated more than a threshold number of activations over a time interval; and

indicating the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

14. The method of claim 13, wherein the threshold number of activations is 20 activations.

15. The method of claim 12, further comprising:

detecting a presence of a leak when the source of negative pressure is activated for a threshold activation duration; and

indicating the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

16. The method of claim 12, wherein the therapeutic negative pressure is configured to range from about −

40 mmHg to about −

125 mmHg.

17. A negative pressure wound therapy apparatus comprising:

a source of negative pressure configured to be fluidically connected to a wound covered by a wound dressing;

a pressure sensor configured to measure pressure under the wound dressing; and

a controller configured to;

determine a therapeutic negative pressure for the source of negative pressure;

initially activate the source of negative pressure to attain the therapeutic negative pressure under the wound dressing, measure wound pressure under the wound dressing at a first sampling rate, determine based on the measured wound pressure that the therapeutic negative pressure has been reached, and subsequently deactivate the source of negative pressure when the therapeutic negative pressure under the wound dressing has been attained; and

after therapeutic negative pressure under the wound dressing has been attained, maintain the therapeutic negative pressure under the wound dressing by alternately activating and deactivating the source of negative pressure based on measuring the wound pressure under the wound dressing at a second sampling rate lower than the first sampling rate, the controller further configured to activate the source of negative pressure in response to determining that the wound pressure is more positive than the therapeutic negative pressure and deactivating the source of negative pressure in response to determining that the wound pressure reaches the therapeutic negative pressure.

18. The apparatus of claim 17, wherein the controller is further configured to:

maintain the pressure under the dressing to within ±

10% of the therapeutic negative pressure by alternately activating and deactivating the source of negative pressure.

19. The apparatus of claim 17, wherein the controller is further configured to:

calculate an average pressure under the dressing;

compare the average pressure to the therapeutic negative pressure; and

initially activate the source of negative pressure and allow the source of negative pressure to be active until the average pressure under the dressing reaches the therapeutic negative pressure, and subsequently deactivate the source of negative pressure.

20. The apparatus of claim 19, wherein the controller is further configured to:

maintain the average pressure under the dressing to within ±

10% of the therapeutic negative pressure by alternately activating and deactivating the source of negative pressure.

21. The apparatus of claim 17, wherein the controller is further configured to:

detect a presence of a leak while maintaining the therapeutic negative pressure under the dressing by determining that the source of negative pressure has been activated more than a threshold number of activations over a time interval; and

indicate the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

22. The apparatus of claim 21, wherein the threshold number of activations is 20 activations.

23. The apparatus of claim 17, wherein the controller is further configured to:

detect a presence of a leak when the source of negative pressure is activated for a threshold activation duration; and

indicate the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

24. The apparatus of claim 20, wherein the controller is further configured to:

detect a presence of a leak while maintaining the average pressure under the dressing by determining that the source of negative pressure has been activated more than a threshold number of activations over a time interval; and

indicate the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

25. The apparatus of claim 24, wherein the threshold number of activations is 20 activations.

26. The apparatus of claim 20, wherein the controller is further configured to:

detect a presence of a leak when the source of negative pressure is activated for a threshold activation duration; and

indicate the presence of a detected leak with at least one of a visual indication, an audio indication, or deactivation of the source of negative pressure.

27. The apparatus of claim 17, wherein the therapeutic negative pressure is configured to range from about −

40 mmHg to about −

125 mmHg.