Pressure sampling systems and methods for negative pressure wound therapy

• US 10,737,002 B2
• Filed: 12/21/2015
• Issued: 08/11/2020
• 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): Marcetich, Adam
• Application Number:
  US15/536,366
• Publication Number:
  US 20170368239A1
• Time in Patent Office: 1,695 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 applying a drive signal to a pump assembly of the pump system, the drive signal alternating between a positive amplitude and a negative amplitude and the drive signal having an offset, and sampling a pressure within a fluid flow path configured to connect the pump system to a wound dressing configured to be placed over a wound during one or more time intervals. Each of the one or more time intervals can occur when the drive signal is approximately at an amplitude equal to one or more sampling amplitudes.

Claims

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

a pump assembly configured to be fluidically connected via a fluid flow path to a wound dressing placed over a wound, the pump assembly comprising;

an actuator; and

a diaphragm;

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

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

apply a drive signal to the pump assembly, the drive signal alternating between a positive amplitude and a negative amplitude and the drive signal having an offset;

determine a plurality of time intervals during which the drive signal is approximately at a sampling amplitude selected for determining pressure in the fluid flow path; and

during application of the drive signal to the pump assembly, sample a plurality of pressures measured by the pressure sensor during the plurality of time intervals and not during other time intervals,

wherein sampling the plurality of pressures during the plurality of time intervals minimizes measurement errors due to pressure fluctuations caused by operation of the actuator of the pump assembly.

2. The pump system of claim 1, wherein the sampling amplitude comprises a local maxima of the drive signal.

3. The pump system of claim 1, wherein the sampling amplitude comprises a local minima of the drive signal.

4. The pump system of claim 1, wherein the sampling amplitude comprises a zero crossing of the drive signal.

5. The pump system of claim 1, wherein the sampling amplitude comprises an offset crossing of the drive signal.

6. The pump system of claim 1, wherein the controller is further configured to sample pressure at least twice during a time interval of the plurality of time intervals.

7. The pump system of claim 6, wherein the controller is further configured to average the pressure samples.

8. The pump system of claim 1, wherein the controller is further configured to adjust at least one parameter of the drive signal based on the sampled plurality of pressures.

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

applying a drive signal to a pump assembly of the pump system configured to be fluidically connected via a fluid flow path to a wound dressing placed over a wound, the drive signal alternating between a positive amplitude and a negative amplitude and the drive signal having an offset;

determining a plurality of time intervals during which the drive signal is approximately at a sampling amplitude selected for determining pressure in the fluid flow path; and

while the drive signal is being applied to the pump assembly, sampling a plurality of pressures measured within the fluid flow path during the plurality of time intervals and not during other time intervals,

wherein sampling the plurality of pressures during the plurality of time intervals minimizes measurement errors due to pressure fluctuations caused by operation of the pump assembly, and

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

10. The method of claim 9, wherein the sampling amplitude comprises a local maxima of the drive signal.

11. The method of claim 9, wherein the sampling amplitude comprises a local minima of the drive signal.

12. The method of claim 9, wherein the sampling amplitude comprises a zero crossing of the drive signal.

13. The method of claim 9, wherein the sampling amplitude comprises an offset crossing of the drive signal.

14. The method of claim 9, further comprising sampling pressure at least twice during a time interval of the plurality of time intervals.

15. The method of claim 14, further comprising averaging the pressure samples.

16. The method of claim 9, further comprising adjusting at least one parameter of the drive signal based on the sampled plurality of pressures.

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

a negative pressure source configured to be fluidically connected via a fluid flow path to a wound dressing placed over a wound;

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

a controller configured to control operation of the negative pressure source, the controller further configured to;

apply a drive signal to the negative pressure source, the drive signal alternating between a positive amplitude and a negative amplitude;

determine a plurality of time intervals during which the drive signal is approximately at a sampling amplitude selected for determining pressure in the fluid flow path; and

during application of the drive signal to the negative pressure source, sample a plurality of pressures measured by the pressure sensor during the plurality of time intervals and not during other time intervals,

wherein sampling the plurality of pressures during the plurality of time intervals minimizes measurement errors due to pressure fluctuations caused by operation of the negative pressure source.

18. The pump system of claim 17, wherein the sampling amplitude comprises a local maxima of the drive signal, a local minima of the drive signal, a zero crossing of the drive signal, or an offset crossing of the drive signal.

19. The pump system of claim 18, wherein the controller is further configured to sample the pressure at least twice during a time interval of the plurality of time intervals.

20. The pump system of claim 19, wherein the controller is further configured to average the pressure samples.

21. The pump system of claim 20, wherein the controller is configured to average consecutive pressure samples.