Pump system for negative pressure wound therapy

• US 20070219532A1
• Filed: 04/12/2007
• Published: 09/20/2007
• Est. Priority Date: 07/14/2005
• Status: Active Grant

• Current Assignee: Paul Hartmann AG (Schwenk Zement KG)
• Original Assignee: Boehringer Technologies LP (Boehringer Laboratories, Inc.)
• Inventors: Karpowicz, John, Kropp, Robert, Norton, Derek, Klocek, Kevin, Boehringer, John, Radl, Christopher
• Granted Patent: US 7,857,806 B2
• Time in Patent Office: Days
• US Class Current: 604/540
• CPC Class Codes: A61M 1/734 Visual indicating means for flow
• CPC Class Codes: A61M 1/74 Suction control underwater drainage A61M1/61
• CPC Class Codes: A61M 1/80 Suction pumps A61M1/64, A61M1/71, A61M60/00 take 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 1/882 Draining devices provided with means for releasing antimicrobial or gelation agents in the drained fluid
• CPC Class Codes: A61M 1/96 Suction control thereof
• CPC Class Codes: A61M 1/964 having venting means on or near the dressing
• CPC Class Codes: A61M 1/966 having a pressure sensor on or near the 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 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3344 Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/3382 Upper level detectors
• CPC Class Codes: A61M 2205/42 Reducing noise
• CPC Class Codes: A61M 2205/6081 Colour codes
• CPC Class Codes: G01F 1/22 by variable-area meters , e.g. rotameters
• CPC Class Codes: G01F 1/28 by drag-force, e.g. vane type or impact flowmeter

Abstract

A pump system for applying negative pressure to a wound, including a flow monitor capable of detecting a deviation from a reference airflow rate provided by a controlled leak to determine whether the system is operating normally or abnormally, and a flow status annunciator to indicate a normal operating condition or whether an abnormal condition is a leak or an occluded line in the system. The pump system further includes a pressure controller for regulating operation of a pump to control pressure in the system at a range around a user-selected setpoint. The pump system may also include a waste collector and a level sensor for detecting when the collector is full.

Claims

1. A pump for applying suction to a wound in a negative pressure wound therapy system, the pump comprising a flow monitor to monitor fluid flow rate in a system conduit from a wound dressing to the pump as indicative of a level of negative pressure applied to a wound, the flow monitor detecting whether or not the flow rate deviates from a reference airflow rate.

2. A, pump as in claim 1, the flow monitor further comprising a non-numerical visual annunciator to indicate whether the flow rate is normal or abnormal, wherein normal flow is defined as a flow rate within a range of the reference airflow rate and abnormal flow is defined as a flow rate that deviates from the reference airflow rate range, and wherein normal flow correlates with a normal level of negative pressure applied to the wound and abnormal flow correlates with an abnormal level of negative pressure applied to the wound.

3. A pump as in claim 2, the annunciator comprising a gradated indicator capable of providing visual indications of flow conditions including that the flow rate is below the reference airflow rate range so as to indicate an occlusion in the system, that the flow rate is within the reference airflow rate range so as to indicate normal operation, that the flow rate is at a first level above the reference airflow rate range so as to indicate a first level of leakage in the system, or that the flow rate is at a second level above the reference airflow rate range so as to indicate a second higher level of leakage in the system, the second level being a greater deviation from the reference airflow than the first level.

4. A pump as in claim 3, wherein the gradated indicator comprises a color-coded bar meter for displaying a different color corresponding to each flow condition.

5. A pump as in claim 1, wherein the pump is a positive displacement pump.

6. A pump as in claim 1, further comprising:

a pressure transducer for sensing pressure in the system; and

a pressure controller for controlling the pump to maintain the system pressure between an upper limit and a lower limit around a pressure setpoint, wherein the pressure controller can control the pump without input from the flow monitor.

7. A pump as in claim 1, further comprising:

a waste collector located in the system between the wound dressing and the flow monitor for collecting liquids aspirated from the wound; and

a docking station for releasably supporting the collector.

8. A pump as in claim 7, further comprising a level sensor proximate to the docking station for detecting the level of waste in the collector.

9. A pump as in claim 8, wherein the level sensor is a capacitance detector.

10. A pump as in claim 8, wherein the level sensor is an optical detector.

11. A pump as in claim 8, wherein the level sensor provides a signal representing a level of waste in the collector and an algorithm is applied to the signal to reduce the likelihood of an erroneous indication of a full collector when the collected waste is sloshed.

12. A pump as in claim 7, wherein gel discs are provided in the collector to gel the waste, thereby inhibiting sloshing of the waste in the collector.

13. A pump as in claim 7, further comprising a dehumidifier disposed between the waste collector and the flow monitor for removing humidity from the system fluid.

14. A pump as in claim 13, wherein the dehumidifier comprises an air-impermeable, water vapor-permeable membrane such that when higher humidity system fluid passes across a side of the membrane and lower humidity ambient air passes across an opposite side of the membrane, water vapor is transported through the membrane from the system fluid to the ambient air.

15. A pump as in claim 2, further including:

an error detector for detecting one or more system errors that are not associated with a deviation of flow rate from the reference airflow; and

an error indicator for displaying a visual warning of system errors detected by the error detector.

16. A pump as in claim 15, wherein the system errors are chosen from the group consisting of:

overpressure detected by the pressure transducer, pressure transducer failure, waste collection canister not attached, low battery voltage, attachment of incorrect power supply, low operating time remaining, collection canister full, and pump motor not operational.

17. A pump as in claim 3, further comprising:

a waste collector located in the system between the wound dressing and the pump for collecting liquids aspirated from the wound;

a docking station for releasably supporting the collector; and

a level sensor proximate to the docking station for detecting the level of waste in the collector;

wherein the gradated indicator is further capable of providing visual indication of a full collector.

18. A pump as in claim 6, the pressure controller further comprising a timer for periodically resetting the pressure setpoint between a user-selected pressure and a second pressure lower than the user-selected pressure for providing intermittent negative pressure therapy to the wound.

19. A pump as in claim 6, wherein the pressure controller further receives an input from the flow monitor when the flow monitor begins to detect a deviation of the flow rate below the reference airflow rate that indicates an occlusion in the system, such that the pressure controller causes the pressure setpoint to temporarily increase above the user-selected pressure, causing the pump to start or to increase in speed to create a negative pressure pulse capable of clearing the system conduit between the wound dressing and the waste collector.

20. A pump as in claim 19, wherein the pressure pulse is initiated prior to the gradated indicator providing indication of an occlusion, and wherein the gradated indicator will not provide an indication of an occlusion if the negative pressure pulse is followed by a decay in the pressure.

21. A pump as in claim 1, further comprising a timing subsystem to record and accumulate time units based upon inputs from various sensors.

22. A pump as in claim 21, wherein the timing subsystem is further capable of providing reports of time histories of pump operation including one or more reports chosen from the group consisting of:

a record of runtime intervals, a record of the date and duration of runtime intervals, a record of total accumulated runtime, a record of accumulated compliant runtime, and a record of runtime remaining on a preset runtime period.

23. A pump as in claim 1, the pump further comprising a charcoal air filter disposed at an air discharge port of the pump.

24. A pump as in claim 1, the pump further comprising a leaf spring sound damper disposed at an air discharge port of the pump.

25. A system for applying negative pressure therapy to a wound, comprising:

a wound dressing including a wound cover that is sealable to skin surrounding a wound;

a portable suction pump powered by a battery or by an alternating current electrical power supply, the pump comprising a flow monitor to detect the flow rate in the conduit;

a conduit having an end operatively associated with the wound dressing and an opposite end operatively associated with the suction pump, to communicate suction to the wound; and

a waste collector disposed in the conduit between the wound dressing and the suction pump for collecting liquids aspirated from the wound, the waste collector being releasably supported by a docking station on the pump.

26. A system as in claim 25, further comprising:

a pressure transducer for sensing pressure in the system; and

a pressure controller for controlling the pump to maintain the system pressure between an upper limit and a lower limit around a pressure setpoint.

27. A system as in claim 25, the pump further including a sensor proximate to the docking station for detecting the level of waste in the collector.

28. A system as in claim 25, wherein the flow monitor detects whether or not the flow rate in the conduit deviates from a range about a reference airflow rate.

29. A system as in claim 28, the pump further including a sensor proximate to the docking station for detecting the level of waste in the collector and the flow monitor further comprising a non-numerical annunciator capable of providing visual indications of flow conditions including that the flow rate is below the reference airflow rate range so as to indicate an occlusion in the system, that the flow rate is within the reference airflow rate range so as to indicate normal operation, that the flow rate is at a first level above the reference airflow rate range so as to indicate a first level of leakage in the system, that the flow rate is at a second level above the reference airflow rate range so as to indicate a second higher level of leakage in the system, the second level being a greater deviation from the reference airflow rate than the first level, or that the waste collector is full.

30. A system as in claim 28, further including an error indicator for displaying a visual warning of one or more system errors that are not associated with a deviation of flow rate through the pump from the reference airflow rate, wherein the system errors are chosen from the group consisting of:

overpressure detected by the pressure transducer, pressure transducer failure, waste collection canister not attached, low battery voltage, attachment of incorrect power supply, low operating time remaining, collection canister full, and pump motor not operational.

31. A system for applying negative pressure therapy to a wound, comprising:

a wound dressing including a wound cover that is sealable to skin surrounding a wound;

a conduit having an end operatively associated with the wound dressing and an opposite end operatively associated with a suction source, to communicate suction to the wound;

a waste collector disposed in the conduit between the wound dressing and the suction pump for collecting liquids aspirated from the wound; and

a flow monitor to monitor system fluid flow in the conduit from the wound dressing to the suction source, the flow monitor detecting whether or not the flow deviates from a reference airflow rate.

32. A system as in claim 31, further comprising a dehumidifier disposed between the waste collector and the flow monitor for removing humidity from the system fluid.

33. A system as in claim 31, wherein the dehumidifier comprises an air-impermeable, water vapor-permeable membrane such that when higher humidity system fluid passes across a side of the membrane and lower humidity ambient air passes across an opposite side of the membrane, water vapor is transported through the membrane from the system fluid to the ambient air.

34. A system as in claim 33, wherein the suction source causes the ambient air to pass across the membrane.

35. A method for applying suction to a wound in a negative pressure wound therapy system comprising:

providing a suction pump;

providing a pressure transducer for sensing pressure in the system;

controlling the pump to maintain the system pressure between an upper limit and a lower limit around a pressure setpoint;

providing a flow monitor to monitor fluid flow rate in the system and to detect whether the flow rate deviates from a reference airflow rate; and

providing a non-numerical visual indicator to indicate whether the flow rate is normal or abnormal, wherein normal flow is defined as a flow rate within a range of the reference airflow rate and abnormal flow is defined as a flow rate that deviates from the reference airflow rate range, and wherein normal flow correlates with a normal level of negative pressure applied to the wound and abnormal flow correlates with an abnormal level of negative pressure applied to the wound.