Dressing status detection for negative pressure wound therapy

• US 10,682,446 B2
• Filed: 12/21/2015
• Issued: 06/16/2020
• Est. Priority Date: 12/22/2014
• Status: Active Grant

• Current Assignee: Smith & Nephew PLC
• Original Assignee: Smith & Nephew PLC
• Inventors: Askem, Ben Alan, Ferrari, Iacopo Claudio, Foini, Matteo, Forzani, Paolo, Fryer, Christopher John, Hunt, Allan Kenneth Frazer Grugeon, Riva, Christian
• Primary Examiner(s): Klein, Benjamin J
• Application Number:
  US15/536,260
• Publication Number:
  US 20180133378A1
• Time in Patent Office: 1,639 Days
• CPC Class Codes: A61M 1/73 comprising sensors or indicators for physical values
• 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 1/82 Membrane pumps, e.g. bulbs
• CPC Class Codes: A61M 1/86 Connectors between drainage tube and handpiece, e.g. drainage tubes detachable from handpiece
• CPC Class Codes: A61M 1/96 Suction control thereof
• CPC Class Codes: A61M 1/962 having pumping means on the suction site, e.g. miniature pump on dressing or dressing capable of exerting suction
• CPC Class Codes: A61M 1/982 with means for detecting level of collected exudate
• CPC Class Codes: A61M 1/985 the dressing itself forming the collection container
• CPC Class Codes: A61M 2205/0272 Electro-active or magneto-active materials
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/42 Reducing noise
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2205/584 : having a color code
• CPC Class Codes: A61M 2205/587 : Lighting arrangements
• CPC Class Codes: A61M 2205/70 : with testing or calibration facilities
• CPC Class Codes: A61M 2205/7536 : allowing gas passage, but preventing liquid passage, e.g. liquophobic, hydrophobic, water-repellent membranes
• CPC Class Codes: A61M 2205/8206 : battery-operated
• CPC Class Codes: A61M 2207/00 : Methods of manufacture, assembly or production
• CPC Class Codes: B29C 65/1635 : at least passing through one of the parts to be joined, i.e. laser transmission welding
• CPC Class Codes: B29C 65/1677 : making use of an absorber or impact modifier
• CPC Class Codes: B29C 65/7802 : Positioning the parts to be joined, e.g. aligning, indexing or centring
• CPC Class Codes: B29C 65/7805 : the parts to be joined comprising positioning features
• CPC Class Codes: B29C 65/7808 : in the form of holes or slots B29C65/7814 takes precedence; holding or clamping means cooperating with specially formed features of at least one of the parts to be joined B29C65/7844
• CPC Class Codes: B29C 66/54 : Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
• CPC Class Codes: B29C 66/71 : characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/7392 : characterised by the material of at least one of the parts being a thermoplastic
• CPC Class Codes: B29C 66/8227 : using springs
• CPC Class Codes: B29C 66/8242 : Pneumatic or hydraulic drives using fluid pressure directly acting on the parts to be joined B29C66/8266
• CPC Class Codes: B29K 2027/18 : PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2059/00 : Use of polyacetals , e.g. POM, i.e. polyoxymethylene or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2077/00 : Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29L 2031/7496 : Pumps
• CPC Class Codes: B29L 2031/753 : Medical equipment; Accessories therefor bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008
• CPC Class Codes: F04B 43/04 : Pumps having electric drive
• CPC Class Codes: F04B 45/047 : Pumps having electric drive
• CPC Class Codes: F04B 49/065 : and making use of computers
• CPC Class Codes: F04B 49/12 : by varying the length of stroke of the working members
• CPC Class Codes: F04B 51/00 : Testing machines, pumps, or pumping installations

Abstract

Systems and methods for controlling a pump system for use in negative pressure wound therapy are described herein. In some embodiments, a method for controlling a pump system includes causing provision of negative pressure, via a flow path, to a wound dressing configured to be positioned over a wound, the flow path configured to fluidically connect the pump system to the wound dressing, measuring a first pressure value in the flow path at a first time, measuring a second pressure value in the flow path at a second time, calculating a first rate of pressure change using the first and second pressure values, and in response to determining that the calculated first rate of pressure change satisfies a threshold rate of change, providing an indication that the wound dressing is full, wherein the method is performed under control of a controller of the pump system.

Claims

1. A pump system configured for negative pressure wound therapy, the pump system comprising:

a pump assembly configured to provide a negative pressure, via a flow path, to a wound dressing configured to be positioned over a wound, the flow path configured to fluidically connect the pump assembly to the wound dressing;

a sensor configured to measure a pressure in the flow path; and

a controller configured to control operation of the pump assembly, the controller further configured to;

determine a first pressure value in the flow path at a first time;

determine a second pressure value in the flow path at a second time; and

in response to determining that the first and second pressure values are between high and low pressure thresholds;

calculate a first rate of pressure change using the first and second pressure values; and

provide an indication that the wound dressing is full in response to determining that the calculated first rate of pressure change satisfies a threshold rate of change.

2. The pump system of claim 1, wherein the controller is further configured to:

measure a third pressure value in the flow path at a third time;

measure a fourth pressure value within the flow path at a fourth time;

calculate a second rate of pressure change using the third and fourth pressure values; and

provide the indication that the wound dressing is full in response to determining that the calculated first and second rates of pressure change satisfy the threshold rate of change.

3. The pump system of claim 2, wherein the controller is further configured to provide an indication of a transient blockage condition in response to determining that the calculated first and second rates of pressure change satisfy a maximum rate of change, the maximum rate of change being greater than the threshold rate of change.

4. The system of claim 2, wherein the controller is configured to calculate the second rate of pressure change using the third and fourth pressure values in response to determining that the third and fourth pressure values are between the high and low pressure thresholds.

5. The pump system of claim 1, wherein the pressure in the fluid flow path is maintained between the high and low pressure thresholds.

6. The pump system of claim 1, wherein the controller is further configured to:

activate the pump assembly in response to determining that pressure in the flow path satisfies the high pressure threshold and deactivate the pump assembly in response to determining that pressure in the flow path satisfies the low pressure threshold.

7. The pump system of claim 1, wherein the controller is configured to provide the indication that the wound dressing is full in response to determining that the calculated first rate of pressure change equals or exceeds the threshold rate of change.

8. The pump system of claim 1, wherein the threshold rate of change is approximately −

50 mmHg/second.

9. The pump system of claim 1, wherein the threshold rate of change is approximately −

70 mmHg/second.

10. The pump system of claim 1, wherein the threshold rate of change is between approximately −

20 mmHg/second and approximately −

200 mmHg/second.

11. The pump system of claim 1, wherein the threshold rate of change is between approximately −

40 mmHg/second and approximately −

100 mmHg/second.

12. The pump system of claim 1, wherein the threshold rate of change is between approximately −

50 mmHg/second and approximately −

75 mmHg/second.

13. The pump system of claim 1, wherein the controller is further configured to provide an indication of a transient blockage condition in response to determining that the calculated first rate of pressure change satisfies a maximum rate of change the maximum rate of change being greater than the threshold rate of change.

14. The pump system of claim 13, wherein the transient blockage condition comprises at least one of a kink in the flow path and or an occlusion in the flow path.

15. The pump system of claim 13, wherein the maximum rate of change comprises about 110%, about 120%, about 130%, about 140%, or about 150% of the threshold rate of change.

16. The pump system of claim 13, wherein the maximum rate of change comprises between about 105% and about 155% of the threshold rate of change.

17. The pump system of claim 13, wherein the controller is further configured to provide an indication of the transient blockage condition in response to determining that the calculated first rate of pressure change equals or exceeds the maximum rate of change.

18. The pump system of claim 1, wherein the controller is further configured to sample a pressure within the fluid flow path during one or more time intervals.

19. The pump system of claim 18, wherein the controller is further configured to sample the pressure at least twice during each of the one or more time intervals.

20. The pump system of claim 18, wherein the controller is further configured to average the pressure samples during each of the one or more time intervals.

21. A method for controlling a pump system configured for negative pressure wound therapy, the method comprising:

causing provision of negative pressure, via a flow path, to a wound dressing configured to be positioned over a wound, the flow path configured to fluidically connect the pump system to the wound dressing;

measuring a first pressure value in the flow path at a first time;

measuring a second pressure value in the flow path at a second time; and

in response to determining that the first and second pressure values are between high and low pressure thresholds;

calculating a first rate of pressure change using the first and second pressure values; and

in response to determining that the calculated first rate of pressure change satisfies a threshold rate of change, providing an indication that the wound dressing is full,

wherein the method is performed under control of a controller of the pump system.

22. The method of claim 21, further comprising maintaining the pressure in the fluid flow path between the high and low pressure thresholds.

23. The method of claim 21, further comprising:

causing provision of negative pressure in response to determining that pressure in the flow path satisfies the high pressure threshold; and

stopping provision of negative pressure in response to determining that pressure in the flow path satisfies the low pressure threshold.

24. The method of claim 21, wherein providing the indication that the wound dressing is full comprises providing the indication in response to determining that the calculated first rate of pressure change equals or exceeds the threshold rate of change.

25. The method of claim 21, wherein the threshold rate of change is approximately −

50 mmHg/second, approximately −

70 mmHg/second, between approximately −

20 mmHg/second and approximately −

200 mmHg/second, between approximately −

40 mmHg/second and approximately −

100 mmHg/second, or between approximately −

50 mmHg/second and approximately −

75 mmHg/second.

26. The method of claim 21, further comprising providing an indication of a transient blockage condition indicating at least one of a kink in the flow path or an occlusion in the flow path in response to determining that the calculated first rate of pressure change satisfies a maximum rate of change, the maximum rate of change being greater than the threshold rate of change.

27. The method of claim 26, wherein the maximum rate of change comprises about 110%, about 120%, about 130%, about 140%, about 150%, or between about 105% and about 155% of the threshold rate of change.

28. The method of claim 26, further comprising providing an indication of the transient blockage condition in response to determining that the calculated first rate of pressure change equals or exceeds the maximum rate of change.

29. The method of claim 21, further comprising:

measuring a third pressure value in the flow path at a third time;

measuring a fourth pressure value within the flow path at a fourth time;

calculating a second rate of pressure change using the third and fourth pressure values; and

providing the indication that the wound dressing is full in response to determining that the calculated first and second rates of pressure change satisfy the threshold rate of change.

30. The method of claim 29, further comprising calculating the second rate of pressure change using the third and fourth pressure values in response to determining that the third and fourth pressure values are between the high and low pressure thresholds.