Apparatus and method for wound volume measurement

• US 9,987,402 B2
• Filed: 11/19/2015
• Issued: 06/05/2018
• Est. Priority Date: 12/06/2007
• Status: Active Grant

• Current Assignee: Smith & Nephew PLC
• Original Assignee: Smith & Nephew PLC
• Inventors: Hartwell, Edward
• Primary Examiner(s): Zalukaeva, Tatyana
• Assistant Examiner(s): Treyger, Ilya
• Application Number:
  US14/946,468
• Publication Number:
  US 20160166740A1
• Time in Patent Office: 929 Days
• CPC Class Codes: A61B 5/0055 by applying suction
• CPC Class Codes: A61B 5/107 Measuring physical dimensions, e.g. size of the entire body or parts thereof
• CPC Class Codes: A61B 5/1073 Measuring volume, e.g. of limbs
• CPC Class Codes: A61B 5/445 Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61F 13/00 Bandages or dressings radioactive dressings A61N5/1029; Absorbent pads
• CPC Class Codes: A61M 1/73 comprising sensors or indicators for physical values
• CPC Class Codes: A61M 1/90 Negative pressure wound therapy devices, i.e. devices for applying suction to a wound to promote healing, e.g. including a vacuum dressing
• CPC Class Codes: A61M 1/982 with means for detecting level of collected exudate
• 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 2205/3344 Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2230/00 Measuring parameters of the user

Abstract

A method and apparatus for measuring a volume of a wound are described, the method comprising the steps of: applying a dressing over a wound, the volume of which is to be measured, the dressing including at least a sealing drape over the wound so as to create a sealed wound cavity; creating a vacuum in said wound cavity by vacuum pump means so as to produce a predetermined vacuum in the wound cavity; measuring a volume of air extracted from said wound cavity in producing said predetermined vacuum; and, calculating a volume of said wound.

Claims

1. A negative pressure wound therapy apparatus comprising:

a source of negative pressure configured to provide negative pressure, via a fluid flow path, to a wound dressing placed over a wound; and

a controller programmed to operate the source of negative pressure, the controller further programmed to;

measure a leak rate in the fluid flow path based on a duty cycle of the source of negative pressure;

provide an indication in response to determining that the measured leak rate exceeds a threshold;

measure a volume of air extracted from at least the wound;

determine a wound volume based at least in part on the measured volume of air; and

correct the determined wound volume based at least in part on the measured leak rate in the fluid flow path.

2. The negative wound therapy of claim 1, wherein the controller is further programmed to:

determine the duty cycle of the source of negative pressure; and

activate an alarm in response to determining that the duty cycle exceeds the threshold, wherein the threshold is indicative of a leak in the fluid flow path.

3. The apparatus of claim 1, further comprising a pressure sensor configured to measure pressure in the fluid flow path.

4. The apparatus of claim 3, wherein the pressure sensor is configured to be positioned in the fluid flow path between the source of negative pressure and a waste canister.

5. The apparatus of claim 1, further comprising a flow sensor configured to measure the volume of air extracted from at least the wound.

6. The apparatus of claim 5, wherein the flow sensor comprises a flow meter.

7. The negative wound therapy of claim 1, wherein the controller is further programmed to:

measure a volume of at least one component located in the fluid flow path to produce a correction factor for determining the wound volume.

8. The apparatus of claim 7, wherein the at least one component located in the fluid flow path comprises at least one of a waste canister, one or more conduits, and the source of negative pressure.

9. The apparatus of claim 8, wherein the controller is further programmed to measure the volume of the waste canister when the waste canister is empty.

10. The apparatus of claim 7, wherein the controller is further programmed to subtract the correction factor from the measured volume of air extracted from at least the wound.

11. The apparatus of claim 1, further comprising a display, wherein the controller is further programmed to provide the cause the corrected wound volume to be displayed on the display.

12. The apparatus of claim 1 wherein the wound volume is computed by a controller programmed to execute software operations.

13. The apparatus of claim 1, wherein the controller is programmed to operate the source of negative pressure to generate negative pressure until a steady state level in the fluid flow path is achieved.

14. A negative pressure wound therapy apparatus comprising:

a source of negative pressure configured to provide negative pressure, via a fluid flow path, to a wound dressing placed over a wound; and

a controller programmed to operate the source of negative pressure, the controller further programmed to;

measure a leak rate in the fluid flow path based on a duty cycle of the source of negative pressure;

provide an indication in response to determining that the measured leak rate exceeds a threshold; and

determine the wound volume and correct the determined wound volume when the wound dressing is being changed.

15. The apparatus of claim 14, wherein the controller is further programmed to:

determine the duty cycle of the source of negative pressure; and

activate an alarm in response to determining that the duty cycle exceeds the threshold, wherein the threshold is indicative of a leak in the fluid flow path.

16. The apparatus of claim 14, wherein the controller is further programmed to:

measure a volume of at least one component located in the fluid flow path to produce a correction factor for determining the wound volume.

17. The apparatus of claim 16, wherein the at least one component located in the fluid flow path comprises at least one of a waste canister, one or more conduits, and the source of negative pressure.

18. The apparatus of claim 17, wherein the controller is further programmed to measure the volume of the waste canister when the waste canister is empty.

19. The apparatus of claim 16, wherein the controller is further programmed to subtract the correction factor from the measured volume of air extracted from at least the wound.

20. The apparatus of claim 14, wherein the controller is programmed to operate the source of negative pressure to generate negative pressure until a steady state level in the fluid flow path is achieved.