DE102014116910A1 - Electronic fluid sensor for negative pressure therapy device - Google Patents

Abstract

The invention relates to a user portable and / or stationary device for providing negative pressure for the negative pressure therapy of wounds on the human or animal body. The device comprises a vacuum generating electrically driven or electrically driven pump, a connection for a suction line leading to the wound site, a vacuum connection, a filter, an electronic control unit for the pump and an electronic liquid sensor for detecting liquid. The invention further relates to the use of an optoelectronic sensor in connection with a device for providing negative pressure for the negative pressure therapy of wounds.

Description

The invention relates to devices and methods for providing negative pressure for medical applications, in particular devices for negative pressure therapy of wounds on the human or animal body and their use. The devices include a pump, a port for a suction line, a vacuum connection, a filter, a control unit and an electronic fluid sensor.

Vacuum therapy of wounds, also referred to in the field as TNP (topical negative pressure) or NPWT (negative pressure wound therapy), has been known for a long time, but has been used increasingly since the mid / late 1990s in particular. In this case, a wound filling material is usually inserted into the wound, the wound area is covered with a foil, and a negative pressure is generated in the wound space by means of a drainage tube and a vacuum pump. By using the wound filling material, the pressure is evenly distributed over the wound. The negative pressure causes, especially in the initial phase of wound treatment, an effective wound cleansing by removing wound exudate.

As further advantages, especially in the subsequent granulation phase, promotion of the formation of granulation tissue and reduction of wound edema formation are mentioned. Negative pressure therapy is usually performed until wound closure. Wound closure is generally considered to be achieved when there is a layer of epidermis over the former wound site. Wound closure can be achieved through healing processes or through surgical procedures.

Low pressure therapy is particularly useful in acute or chronic wounds such as ulcers (e.g., pressure sores, diabetic, neuropathic or venous ulcers), traumatic wounds, refractory wounds, infected wounds, postoperative wounds, probed fistulas, and skin flaps and skin grafts. Chronic wounds are characterized by slow or absent wound healing.

A conventional device for negative pressure therapy of wounds normally comprises a suction pump (also referred to in the art as "vacuum source"), one or more sensors for pressure monitoring, a control unit for controlling the pump including a data memory, controls for the user (eg switches, Indicator lights or a display), optionally terminals for data communication, a power supply for the pump and the control unit (for example, an accumulator and / or a power supply), a fluid receptacle for receiving extracted from a wound body fluids, a connection for one or more to Wound leading suction lines, filters to prevent suction of bodily fluids into the pump, and vacuum connections to establish fluid communication between each component.

Devices for negative pressure therapy of wounds are known in the art. Suitable negative pressure therapy equipment and accessories, for example, in the documents WO2011018132 . WO2011018133 . WO2012156140 . WO2012156174 . WO2012163617 and WO2013159904 described. The documents WO2014023501 and WO2011076340 disclose suitable vacuum port means (port) for establishing a vacuum connection with the wound dressing. In the wound room, for example, from the documents WO2010072309 . WO2012022484 . WO2011072840 . WO2012167942 or WO2011003521 known wound dressings are introduced. According to the applicant's experience, a wound dressing made of an open-celled polyester polyurethane foam, which has been disclosed in US Pat WO2012022485 is described in more detail, proved.

Devices for negative pressure therapy of wounds are commercially available. The range of devices available on the market includes small, portable devices that allow patients a degree of mobility through to stationary devices, such as long-term care facilities. Furthermore, devices are available, such as in the WO2011018132 or WO2011018133 described, which are suitable for both stationary and mobile operation. Accessories suitable for negative pressure therapy, such as, for example, wound dressings, further dressing components or connecting agents, are likewise commercially available.

The term "fluid" is used in the present document as a generic term for liquids (for example, water, rinsing liquids or body fluids) and gases (for example, air or water vapor). In the leading from the wound to the therapy device lines (suction line, Vacuum connection) may be liquids (in particular body fluids), gases (in particular air) or mixtures of liquids and air. Liquid may also be present in the form of very fine droplets in the air sucked towards the device. Furthermore, the air can contain a high proportion of water vapor (humid air).

During the negative pressure treatment body fluids are sucked out of the wound area. This may in particular be blood, wound exudate with different proportions of water as well as rinsing liquids. Rinsing fluid accumulates, for example, in the so-called instillation therapy. In this case, in alternation with the application of negative pressure, a wound-cleaning solution and / or a wound-healing-promoting solution are applied to the wound area. The liquid volumes typically incurred in negative pressure therapy depend on the particular treatment method used and can be subject to considerable fluctuations. In the post-operative use of negative pressure therapy for the treatment of surgical wounds often only a small amount of fresh blood is aspirated. By contrast, large volumes (up to several liters per day) of bodily fluids with a high water content can occur, for example, in the case of negative-pressure therapy on the open abdomen.

In the known from the prior art devices for negative pressure therapy (see, for example, the above-mentioned WO2011018132 ) are often provided liquid receptacle for receiving extracted from a wound body fluids. For reasons of hygiene, these are usually containers which are disposed of after a single use (disposable container). Furthermore, there are also systems for negative pressure treatment of wounds, in particular for the treatment of wounds with low exudate levels, in which no liquid receptacle is provided. The wound exudate is then stored in such devices usually in the wound dressing, the dressing having liquid-absorbing components, see for example the WO2009066105 ,

In any case, in the construction of a device for negative pressure therapy of wounds, the problem arises that the extracted body fluids, which are often contaminated with infectious components, must not reach the negative pressure source. Ingress of body fluids into the vacuum source can damage the pump or pump components. This can lead to an immediate failure of the pump, so that the therapy must be interrupted and a replacement device must be procured. The ingress of lesser amounts of liquid can shorten the life of the pump. Furthermore, there is a risk that the liquid is sucked through the pump and blown through an outlet of the pump into the interior of the device. This device components can be damaged and contaminated with infectious fluids. In the worst case, infected fluid enters the environment. Contamination of the interior of the device or the environment may occur without the user noticing. Contaminations inside the therapy device may endanger, for example, the technician who later waits for the device. Contaminations in the environment can endanger the patient, the medical staff as well as other persons who are in the vicinity of the therapy device.

It is therefore necessary to reliably separate off liquid fractions which are present in the air stream taken in by the pump. A separation of air and liquid is usually already by a suitable construction of the container, if one is provided. As mentioned above, it is also possible to retain lower levels of body fluids in absorbent layers of the wound dressing. Separation of air and liquid in this case takes place by means of the absorbent layers of the wound dressing.

Body fluids may enter the vacuum source, particularly if the fluid receptacle or other device used to collect the aspirated fluids, such as an absorbent bandage, is full or saturated and the vacuum source is not timely turned off. Furthermore, liquids in the form of small droplets can be entrained by the air flow and thus penetrate into the vacuum source.

The commercially available devices, also referred to herein as negative pressure therapy unit, therefore usually contain a filter in the vacuum line, which is to prevent the ingress of liquid into the pump. For devices having a fluid receptacle, the filter is usually located between the receptacle and the inlet of the pump. Often, the filter, which is usually a microfilter, is securely connected to the container and is disposed of when the container is replaced. For devices without fluid receptacle in which the wound secretions are stored in the wound dressing, the filter is usually in the dressing component, see the above-mentioned WO2009066105 , The nature of the filter is such that air can pass through, but liquid is retained. Furthermore, common negative pressure therapy devices often have a mechanism which ensures that the device is turned off when the container (if any) is full.

During normal operation of the negative pressure therapy device, the above-mentioned filters, optionally supplemented by a shut-off mechanism with a full container, prevent the entry of liquid into the pump.

However, undesirable liquid entry into the line leading to the pump, and thus ultimately into the pump, may occur if the filter is defective. It is conceivable that a filter due to a manufacturing error already at the beginning of the application of negative pressure at least small amounts of liquid through. However, such a defect can also occur with an initially intact filter in the course of the vacuum operation. In particular, it is conceivable that an initially intact filter initially restrains the incoming liquid. The liquid retained by the filter moistens the filter. If the humidified filter is then exposed to sustained negative pressure for a prolonged period of time, for example if the shut-off mechanism malfunctions, the filter can "break through" so that liquid can enter the line leading to the pump.

The inventors involved in the present invention were faced with the task of improving negative pressure therapy devices. In particular, such therapy devices should be better protected against unwanted ingress of liquid into the negative pressure generating device. It was also desirable to develop methods that would allow safer operation, including the maintenance of such a device. Furthermore, life and reliability of such devices should be increased. In practice, there was also the requirement to ensure effective containment of the aspirated, partially highly infectious bodily fluids, i. It should be reliably prevented that the liquids get inside the device or contaminate the environment of the device.

The objects have been achieved by means of a user-portable and / or stationary device for providing negative pressure for the negative-pressure therapy of wounds on the human or animal body. The device comprises a (in operation of the device) generating the negative pressure electrically driven pump with an inlet for sucking air, with an outlet for blowing air and with an interior which can communicate with inlet and outlet, a connection for a suction line leading to the wound site, a vacuum connection between the connection and the inlet, so that a vacuum communication between the pump and the suction line leading to the wound site can be produced, at least one filter which is impermeable to liquids in the intact state, wherein the filter in the vacuum connection is arranged, and an electronic control unit for the pump. The device according to the invention is characterized in that the device further comprises at least one electronic liquid sensor which can communicate with the control unit, wherein the at least one liquid sensor is arranged downstream of the filter. The term "downstream" is in this case based on the fluid flow, which is moved in the intended use of the device in the negative pressure therapy, starting from the wound in the direction of the pump and on to the pump outlet.

The provision of an electronic liquid sensor located downstream of the filter can increase the operational safety and life of a negative pressure therapy device and facilitate the maintenance of the device.

• i) Unmittelbar stromabwärts des Filters befindet sich normalerweise der Abschnitt zwischen dem Filter und dem Einlass der Pumpe. Der Abschnitt zwischen dem Filter und dem Einlass der Pumpe wird üblicherweise durch ein Leitungsmittel gebildet, beispielsweise durch einen Silikonschlauch. Es wäre grundsätzlich auch möglich, den Filter unmittelbar an dem Einlass der Pumpe anzubringen. In diesem Falle ist dann zwischen dem Filter und dem Einlass der Pumpe kein Leitungsmittel vorhanden.
• ii) Weiter stromabwärts ist die Pumpe, welche im Betrieb den Fluidstrom bewegen kann, vorhanden. Die Pumpe umfasst einen Einlass zum Ansaugen von Luft, einen Innenraum, durch den der Fluidstrom hindurch bewegt wird sowie einen Auslass zum Ausblasen der Fluide. Der Innenraum kann bei Betätigung der Pumpe wechselseitig sowohl mit dem Einlass als auch mit dem Auslass kommunizieren.
• iii) Der Auslass kann in eine Öffnung münden, so dass die Fluide unmittelbar in die Atmosphäre entlassen werden. Alternativ können stromabwärts des Auslasses weitere den Fluidstrom leitende Komponenten vorhanden sein. Der "Bereich des Auslasses der Pumpe" umfasst nach der hier verwendeten Begrifflichkeit dem Auslass der Pumpe nachgeschaltete Leitungsmittel oder sonstige Hohlräume, deren stromabwärts gelegene Öffnung dann in die Atmosphäre mündet. Insbesondere umfasst der Bereich des Auslasses in der Praxis häufig Geräuschdämpfungselemente und/oder Geruchsabsorber.

Downstream of the filter, in the fluid system of the device, starting from the filter, there are substantially the following sections:

• i) Immediately downstream of the filter is normally the section between the filter and the inlet of the pump. The section between the filter and the inlet of the pump is usually formed by a conduit means, for example by a silicone tube. It would also be possible in principle to attach the filter directly to the inlet of the pump. In that case there will be no conduit between the filter and the inlet of the pump.
• ii) Farther downstream is the pump, which can move the fluid flow during operation. The pump includes an inlet for drawing in air, an interior through which the fluid flow is moved, and an outlet for blowing out the fluids. The interior can mutually communicate with both the inlet and the outlet when the pump is actuated.
• iii) The outlet can open into an opening so that the fluids are released directly into the atmosphere. Alternatively, further fluid flow conductive components may be present downstream of the outlet. The "outlet portion of the pump", as used herein, includes conduit means downstream of the outlet of the pump or other cavities, the downstream opening of which then discharges into the atmosphere. In particular, the area of the outlet often comprises noise damping elements and / or odor absorbers in practice.

The suction line leading to the wound site can be connected to a vacuum dressing, which usually comprises at least one wound dressing and an airtight cover (typically a self-adhesive film), the cover being adhesively fixed to the intact skin surrounding the wound. The wound dressing is often an open-cell foam, for example the one mentioned in the above WO2012022485 described polyester polyurethane foam, which may optionally be applied in conjunction with an additional wound contact layer. The vacuum communication between the suction line and the wound dressing is normally made by a vacuum connection means (port). The dressing components referred to herein are commercially available, for example under the name of Hydro film ^® (air-tight covering), "VivanoMed ^® Foam" (polyester-polyurethane), "VivanoMed ^® Silicone Layer" (wound contact layer), and "VivanoTec ^® Port" (vacuum connection means) , each from the manufacturer Paul Hartmann AG (Germany).

The vacuum generating electrically driven or electrically driven pump is often a diaphragm pump, which is controlled and controlled by the electronic control unit. In principle, any conventional suction pump can be used within the scope of the invention. The electronic control unit is preferably a programmable control unit which can communicate with an external electronic device via an interface, for example a USB interface. By means of the communication connection with the external device, for example with a portable computer, the control unit can be programmed and / or operating data stored on the control unit can be queried as part of a maintenance. While performing the negative pressure therapy, the external electronic device is normally not connected to the device. The electronic control unit preferably comprises operating elements, for example a touchscreen, by means of which a user sets the negative-pressure therapy device in motion and the parameters desired for the therapy method (in particular height and duration of the negative pressure to be applied or possibly a complex therapy scheme with alternating phases of higher or lower negative pressure). can enter. A negative pressure therapy unit with an electrically driven pump, with electronic control unit and with touchscreen is commercially available, for example, under the name "VivanoTec ^® negative pressure unit" from the manufacturer Paul Hartmann AG (Germany).

The vacuum connection between the inlet of the pump and the connection for the suction line makes it possible to establish a vacuum communication between the pump and the suction line. The vacuum connection is normally one or more interconnected conduit sections made of plastic. The vacuum connection and / or the wound suction line should be of suitable length so that the device can be provided spaced from the wound site. Insofar as the device has an optional existing liquid receptacle, the receptacle interior can also form a part of the vacuum connection when the receptacle is arranged between the pump and the connection.

In the vacuum connection, a filter is arranged, which is permeable to the intake air in the dry state and at the same time blocks the passage of liquid to - at least in the intact state - to prevent the entry of liquid in the downstream of the filter existing portions of the fluid system. Examples of suitable filters include membrane filters (for example made of cellulose layers) or filters made of a porous solid (for example a ceramic material, a plastic material, a metal or a sintered body). In the case of filters based on porous solids, one or more additional swellable components may advantageously be present (for example carboxymethyl cellulose), which block the passage of fluid as soon as the filter is soaked through.

• i) zwischen dem Filter und dem Einlass der Pumpe, und/oder
• ii) an dem Einlass der Pumpe und/oder
• ii) in dem Innenraum der Pumpe und/oder
• iii) an dem Auslass der Pumpe und/oder
• iv) an dem Bereich des Auslasses der Pumpe angeordnet sein.

According to the invention, at least one electronic liquid sensor is arranged downstream of the filter. The at least one electronic liquid sensor can accordingly

• i) between the filter and the inlet of the pump, and / or
• ii) at the inlet of the pump and / or
• ii) in the interior of the pump and / or
• iii) at the outlet of the pump and / or
• iv) be arranged at the region of the outlet of the pump.

Preferably, at least one electronic fluid sensor is disposed in the section between the filter and the inlet of the pump (section i) and / or in the region of the outlet of the pump (section iv).

The advantages achievable with the invention can often already be achieved with a single, arranged downstream of the filter electronic liquid sensor. This should then preferably be mounted in the section between the filter and the inlet of the pump.

According to its location in the fluid system of the device, the at least one electronic fluid sensor can detect fluids that have entered the filter downstream. In practice, a portion of the fluid system present in the downstream of the filter can occur in particular in the case of a defective filter. The electronic fluid sensor is thus provided in particular for the detection of fluid, which has undesirably penetrated through a defective filter in the downstream of the filter existing portions of the fluid system.

Preferably, the device comprises an electronic liquid sensor, which is arranged between the filter and the inlet, since in this way the liquid inlet can already be detected before the liquid has penetrated into the pump. Namely, when using the preferred embodiment of the invention mentioned here, it is possible to switch off the pump already immediately after a detection of liquid in the portion of the vacuum connection leading to the pump before liquid enters the pump. In this way, a contamination of other device components and even the environment in which the device is used to be prevented. The invention thus also encompasses a device of the type described here, wherein the electronic control unit can deactivate the pump immediately after a detection of liquid in the portion of the vacuum connection present between the filter and the inlet. In particular, this can be prevented that liquid is sucked through the pump and blown through the outlet from the closed fluid system. In this case, advantageously, the low response threshold of an electronic fluid sensor and the high processing speed of an electronic control unit can be utilized.

Alternatively or additionally, it is possible to emit an audible and / or visual warning signal when the electronic fluid sensor responds to alert the user to the ingress of fluid into the downstream portion of the fluid system.

According to a preferred embodiment of the invention, a sensor signal for immediate shutdown of the pump and for outputting a warning signal (visually and / or acoustically). At the same time, the event is recorded in an electronic memory belonging to electronic memory. Optionally, an additional message via a remote data communication could be issued if the device has a corresponding communication device. It would then be possible, among other things, to alert the medical care staff and / or a service center of the device manufacturer to the defective filter.

According to a further particularly preferred embodiment of the invention, a sensor signal leads to the immediate switching off of the pump, to the issuing of a warning signal and to the blocking of the negative pressure therapy unit for the user. The blockage of the negative pressure therapy unit can only be canceled by a service technician of the device manufacturer, but not by the user. This is a precautionary measure designed to ensure that a device that may be contaminated with wound secretions is no longer being used and is being expertly reviewed.

Alternatively or additionally, the response of the electronic liquid sensor can be recorded in an electronic memory belonging to the electronic control unit. In addition to the response of the sensor and, where appropriate, the intensity or the course of the sensor signals, the time of the event or the events should be registered. The stored information for the response of the sensor can then be retrieved, for example in the course of maintenance of the device. The maintenance technician thus receives information on events that have occurred in the past, in particular may indicate a defective filter. Corresponding messages for liquid entry could then give rise, for example, to a check or replacement of the pump. Furthermore, the technician receives the indication of a possible contamination of the interior of the device by body fluids. Accordingly, the device could then be disinfected or completely put out of service. When selecting the measures to be taken, the number and type of sensor messages can also be used. So it could be possible to a certain extent to make a conclusion on the amount of liquid infiltrated on the frequency and intensity of the sensor signals. The invention therefore comprises the use of a liquid sensor in a negative pressure therapy device of the type described herein for detecting liquid entry in downstream portions of the fluid system as part of a safety inspection or maintenance of the device. The invention also includes the use of the liquid sensor to protect the pump, the device and the environment from contamination.

• i) Bereitstellen einer Vorrichtung, wie vorstehend beschrieben,
• ii) anschließend Abrufen des Speicherinhaltes der elektronischen Steuerungseinheit, um zu überprüfen, ob während des vorangehenden Betriebes ein Flüssigkeitseintritt in stromabwärts des Filters angeordnete Abschnitte des Fluidsystems aufgetreten ist,
• iii) nachfolgend gegebenenfalls Dokumentation der Überprüfung.

Likewise, the invention includes a maintenance method for detecting liquid entry in downstream of the filter disposed portions of the fluid system. The maintenance procedure includes the following steps:

• i) providing a device as described above,
• ii) subsequently retrieving the memory contents of the electronic control unit to check if any fluid entry into downstream portions of the fluid system has occurred during the preceding operation,
• iii) below, if applicable, documentation of the review.

• – Austausch des Filters,
• – Austausch oder Überprüfung des zwischen dem Filter und dem Einlass der Pumpe angeordneten Abschnittes der Unterdruckverbindung, sofern vorhanden,
• – Austausch oder Überprüfung der Pumpe einschließlich des Auslasses,
• – Überprüfung und gegebenenfalls Dekontamination des Gehäuseinnenraumes,
• – Überprüfung und gegebenenfalls Dekontamination der Umgebung, in der die Vorrichtung eingesetzt war.

If the storage contents contain messages which point to a section of the fluid system arranged downstream of the filter during a preceding operation, it must therefore also be assumed that the liquid has entered the pump. Portions of the vacuum connection disposed downstream of the filter also indicate that the filter has malfunctioned in one or more of the previous uses of the devices. Furthermore, there is a risk of damage to the pump by the liquid penetrated. In the worst case, body fluids may have been sucked through filters and through the pump and blown out into the housing of the device or into the environment. Accordingly, the above-mentioned method for detecting liquid entry in the case of positive liquid detection is followed by one or more of the following steps:

• - replacement of the filter,
• Replacement or checking of the portion of the vacuum connection between the filter and the inlet of the pump, if any,
• - replacement or inspection of the pump, including the outlet,
• - checking and possibly decontaminating the interior of the housing,
• - Checking and possibly decontaminating the environment in which the device was used.

It would also be conceivable to carry out the programming of the control unit in such a way that a reaction dependent on the intensity of the sensor signals takes place. This can be done, for example, such that sensor signals, which indicate a very small amount of liquid that has entered, are merely stored in the memory of the control unit, so that they can be retrieved in the course of maintenance. On the other hand, sensor signals that indicate the ingress of a larger amount of liquid could lead to an immediate shutdown of the pump and, if necessary, to a blockage of the device for the user.

The stored messages could be made available via remote data communication, for example in connection with remote maintenance of the device by a service center of the device manufacturer.

According to the above-described measures after the detection of liquid in downstream of the filter arranged portions of the fluid system, the present invention comprises the use of a liquid sensor, in particular an optoelectronic liquid sensor, in a device of the type described herein for detecting liquid entry in downstream of the filter disposed portions of the fluid Systems. The invention preferably comprises the use of a liquid sensor, in particular of an optoelectronic liquid sensor, for safety shutdown of the pump and / or for alerting a user and / or for storing the event in an electronic memory belonging to the electronic control unit. Under a safety shutdown of the pump is in the present case understood as an immediate deactivation of the pump in the detection of liquid in the downstream of the filter disposed portions of the fluid system.

According to the invention, the liquid sensor must be able to communicate with the control unit, since the detection of a liquid inlet into the sections of the fluid system arranged downstream of the filter takes place by means of the control unit on the basis of the sensor signal. The communication is preferably carried out by a direct electrical connection. The communication can also be realized by a different type of connection, for example by an optical connection (fiber optic) or wirelessly by radio link.

In the context of the invention disclosed herein, the device preferably comprises a fluid receptacle for receiving body fluids extracted from the wound. Advantageously, the liquid receiving container is arranged in the vacuum connection between the filter and the connection for the suction line leading to the wound site. The container then has at least one inlet for supplying the body fluids and at least one outlet for application of negative pressure.

The liquid receiving container serves to receive and store the liquids sucked from the wound site on the patient, for example wound exudate and / or rinsing liquid. The fluid receptacle is usually a disposable article which is discarded after the vacuum therapy. Advantageously, the manufacturer provides liquid receiving containers with different capacities. Smaller containers, for example with a capacity of 100 ml to 400 ml, could be provided for the mobile operation of the device, while larger containers, for example with a capacity of 400 ml to 2000 ml, then be used for a stationary operation.

In the area of the inlet for feeding the body fluids, the connection for the suction line leading to the wound site can be attached. Alternatively, it is possible that at the inlet a conduit means is present, at its pointing to the patient's body end then the connection for the suction line is attached. In this case, the aforesaid conduit forms part of the vacuum connection between the port and the inlet of the pump. The vacuum connection then continues through the interior of the container and the container exit via the filter to the inlet of the pump.

The filter may be present directly in the region of the container outlet which serves to apply negative pressure. In particular, the filter may be firmly and permanently attached to the container. It would also be possible to connect the filter with the container outlet via a conduit means.

The device according to the invention can be used particularly advantageously in particular if the aspirated liquids are stored in the receptacle in liquid form until disposal. By the term "storage in liquid form" it is meant that there are no thickening agents (also called "trapping agents") in the container.

In particular, the aspirated liquids are not stored in thickened form until disposal.

Preferably, the liquid receiving container has in its interior by ribs or projections formed areas or mutually communicating chambers, so that the body fluids collected in the interior of the container are prevented in a movement of the container in the uncontrolled slosh.

It has proved to be particularly advantageous if the device comprises a first housing part with a negative pressure generating means (pump) and a second housing part, which forms the liquid receiving container and which manually attachable to the first housing part of the device and manually from the first housing part of the device is solvable, includes. Advantageously, the second housing parts (liquid receiving container) are provided by the manufacturer with different capacities. Smaller containers, for example with a capacity of 100 ml to 400 ml, could be provided for the mobile operation of the device, while larger containers, for example with a capacity of 400 ml to 2000 ml, then be used for a stationary operation. The same first housing part can then be combined as required with different second housing parts, so that the therapy device, which forms the first housing part, both for mobile operation and for stationary operation, for example in the hospital, can be used.

In the first housing part, among other things, the control unit, the liquid sensor and possibly a power supply should be accommodated in addition to the pump. In the power supply, the for the operation of electrical or electronic components (for example, pump, liquid sensor, control unit or controls) is required, it can be in particular a power supply and / or a battery. Furthermore, operating elements for the device (means for operating the control unit by a user), in particular a touchscreen display, may be present on the first housing part. According to the invention it is preferred if all components of the therapy device are housed or provided on the or in the first housing part, which are provided for a permanent use. In contrast, the second housing part preferably comprises the intended for single use components of the therapy device, namely the liquid receptacle and either the connection for the suction line, which is located directly on the container or a line leading to the connection including the terminal.

Furthermore, the second housing part preferably comprises the filter so that it can be disposed of together with the container. According to a particularly preferred embodiment, the filter is arranged directly at the outlet of the liquid receiving container.

The electronic fluid sensor is a sensor suitable for detecting fluid. In particular, the sensor must be suitable for detecting liquid present in a closed interior. Suitable sensor types for the detection of liquid include, for example, sensors which are based on the measurement of light (optoelectronic sensors), sensors which are based on the measurement of electrical capacitance (capacitive sensors) or sensors which detect liquid due to a change in the electrical conductivity (conductive conductivity) Sensors) can prove.

Preferably, in connection with the present invention, an optoelectronic liquid sensor is used, since an optoelectronic liquid sensor has a suitable sensitivity and responds very quickly (in the millisecond range) to the presence of liquid or liquid droplets in the measuring path. The presence of liquid in the tube is detectable by a change in the optical density (transmission) or by a change in the refraction of the light.

Photocells that register a change in transmission are commercially available and very cost effective. The fluids to be detected are, in particular, body fluids, rinsing fluids or mixtures thereof. Body fluids are usually colored and can easily be detected by a light barrier. The rinsing liquids used, for example, for instillation therapy, on the other hand, are clear liquids (saline solutions) which less dampen the transmission. For the detection of clear liquid in the interior of a line means, the measurement should therefore take place at a wavelength which is sufficiently absorbed by an aqueous solution, for example in the UV range less than 240 nm or in the long wavelength range greater than 600 nm. Even more sensitive measurements are possible by means of a change in the refraction, whereby usually a laser light barrier is used. Sensor modules with laser light barriers are likewise commercially available.

When using an optoelectronic liquid sensor, it has proved to be particularly advantageous if that portion of the vacuum connection, which is located between the filter and the inlet, is formed by a transparent tube and the sensor is attached to the outside of the transparent tube. When using optical sensor means, the liquid sensor should be located in a darkened area of the device, since the detection of liquid in the hose could otherwise be disturbed by ambient light. The darkening can be done by a housing in which the liquid sensor and the other electronic components of the device are housed. Commercially available liquid sensors comprising a light source and a phototransistor are suitable for practical use. As the light source, an LED lamp is usually used. The light source and the phototransistor are combined with a hose holder to a sensor assembly and arranged such that when inserted hose suitable for the measurement positioning of the optical elements is ensured. The assembly may include a calibration module to compensate for manufacturing-related differences in the optical elements, changes in the optical elements due to aging, and variations in the power supply. Furthermore, the sensor assembly may be mounted on a circuit board, for example on the board, which also carries the control unit. An electronic liquid sensor with LED, phototransistor and hose holder suitable for the present invention is available, for example, under the designation OPB350 from OPTEK Technology Inc. (USA). Based on the output from the liquid sensor electrical Signals ("sensor output"), the states "no liquid present" and "liquid present" can be distinguished.

Threshold values of the sensor output, whose overshoot or undershoot can be interpreted by the control unit as the presence or absence of liquid in the respective section of the fluid system, serve to delimit the different states.

Alternatively or additionally, it is possible to use the time change of the sensor output, which is present on the optoelectronic sensor, for the detection of liquid in the vacuum connection. The present invention therefore includes a method of detecting liquid intrusion in downstream of the filter disposed portions of the fluid system, wherein the present at the optoelectronic sensor temporal change of the sensor output by the electronic control unit is then evaluated as liquid penetration, if a rapid increase or a rapid drop in sensor output (measured as voltage or current) occurs. Here, under a rapid increase or decrease, a change in the voltage applied to the sensor or the current flowing through the sensor by more than 10% per minute, preferably more than 10% per 1 second, more preferably more than 10% per 0 , 1 second, in particular by more than 10% per 10 milliseconds, understood. The evaluation of the time available on the optoelectronic sensor change of the sensor output allows a very fast and sensitive detection of liquid entry into the respective sections of the fluid system. A quick detection of the liquid entry is advantageous because the control unit can then initiate the measures provided, for example, an emergency shutdown of the pump at an early stage.

In connection with the detection of the liquid ingress on the basis of the temporal change of the sensor signals d (sensor output) / dt (for example the temporal change dU / dt of the voltage measured in V / s at the optoelectronic sensor), a suitable threshold value for the state "fluid present" are determined. The threshold, which is indicated for example in the unit volts per second (V / s), then serves to detect the liquid entry, so that, for example, issued an alarm message and the pump is deactivated. To determine a suitable threshold value, the fluctuation of the sensor output is first determined. This is preferably done when the measuring area (for example a tube section) is dry. The standard deviation σ of the sensor signals is determined from the measured values. The threshold value for the rate of change (d (sensor output) / dt) is then obtained by multiplying the determined standard deviation σ by a suitable multiplication factor. It has been shown that the multiplication factor should be between 5 and 20 in order to ensure sensitive and error-free detection. Preferably, the factor is 10 to 15, in particular 12 to 13. The detection method described herein enables the very fast (in the millisecond range) detection of very small amounts of liquid (in the μl range), even if the liquid is in the form of very fine droplets.

According to a particularly advantageous embodiment of the invention, the device comprises an optoelectronic liquid sensor, which can detect a change in the transmission and / or refraction due to a liquid. The sensor is arranged in that section of the vacuum connection which is located between the filter and the inlet of the pump, the section being formed by a transparent hose, in particular by a silicone hose. In this case, the sensor is mounted on the outside of the transparent tube, so that the presence of liquid in the tube causes a detectable by the sensor change in the transmission and / or refraction. The electronic control unit then evaluates the sensor signals (sensor output) as ingress of liquid into the relevant section of the vacuum connection when a preset threshold value for the temporal change of the sensor signals (d (sensor output) / dt) is exceeded. The threshold is in this case 3 times to 30 times, in particular 5 times to 20 times, particularly preferably 10 times to 15 times, very particularly preferably 12 times to 13 times the standard deviation σ, where the standard deviation σ is determined on the basis of at least 5 consecutive measurements of the sensor output of a sensor applied to a dry hose. The sensor signals mentioned here (sensor output) are preferably the voltage U in volts measured at the optoelectronic sensor. As a change over time of the sensor signals, the time change of the voltage dU / ds then results in volts per second (V / s).

If appropriate, a suitable detection method can also include the simultaneous evaluation of both threshold values and temporal change rates of the sensor output: Accordingly, the control unit interprets the sensor output as liquid entry into the vacuum connection, if either exceeds or falls below absolute threshold values of the sensor output or if the rate of change exceeds a preset value.

• i) Bereitstellen einer erfindungsgemäßen Vorrichtung,
• ii) Durchführen der Unterdrucktherapie,
• ii) Überwachung der stromabwärts des Filters angeordneten Abschnitte des Fluidsystems mittels eines Flüssigkeitssensors,
• iv) Im Falle einer Detektion von Flüssigkeitseintritt in die stromabwärts des Filters angeordneten Abschnitte des Fluidsystems ein oder mehrere Wartungs- und/oder Sicherheitsmaßnahmen wie beispielsweise: – Ausgabe eines Warnsignals an dem Gerät (optisch und/ oder akustisch) – Sicherheitsabschaltung der Pumpe – Sperre der Unterdruck-Einheit für den Benutzer, wobei eine Rücksetzung der Sperre nur durch einen Servicetechniker möglich ist (beispielsweise durch Eingabe eines Codes) – Austausch des Filters oder des zur Pumpe hinführenden Abschnittes der Unterdruckverbindung – Überprüfung, Austausch oder Entsorgung der Pumpe einschließlich des Auslasses – Überprüfung und gegebenenfalls Dekontamination des Gehäuseinnenraumes – Entsorgung der Unterdrucktherapieeinheit – Überprüfung und gegebenenfalls Dekontamination der Umgebung, in der die Vorrichtung eingesetzt war.

The present invention further relates to a method for negative pressure therapy of wounds, comprising the steps:

• i) providing a device according to the invention,
• ii) performing the negative pressure therapy,
• ii) monitoring the downstream of the filter disposed portions of the fluid system by means of a liquid sensor,
• iv) In the case of detection of liquid entry into the downstream of the filter arranged portions of the fluid system one or more maintenance and / or security measures such as: - Issue a warning signal to the device (visually and / or acoustically) - Safety shutdown of the pump - lock the Vacuum unit for the user, which can only be reset by a service technician (eg by entering a code) - Replacement of the filter or the section of the vacuum connection leading to the pump - Checking, replacing or disposing of the pump including the outlet - Checking and if necessary decontamination of the housing interior - Disposal of the vacuum therapy unit - Checking and possibly decontaminating the environment in which the device was used.

The apparatus described herein may additionally include a liquid indicator for indicating and / or detecting liquid which has entered portions of the fluid system disposed downstream of the filter. In this context, a liquid indicator is understood as meaning a substance which exhibits a color change or a color change after the liquid has been absorbed. The color change can also be a change in color intensity. The indicator substance is normally applied to a carrier. It would also be possible to apply the substance directly to components of the vacuum connection, for example to the inside of a conduit means. A liquid indicator, in which the penetration of liquid is already visible to the naked eye, can be provided as an additional safety measure. It is also conceivable to detect the color change or the color change likewise electronically. This can be done by means of the liquid sensor already present in the device according to the invention or by means of an additional optoelectronic sensor. Furthermore, it may prove advantageous to provide an additional liquid indicator which is provided inside the housing of the device but outside the fluid system. Such an indicator may alert maintenance personnel that the device has undesirable liquid contact. Such liquid indicators are known from the prior art and are used regularly, for example, in mobile phones.

Further details, features and advantages of the invention will become apparent from the appended claims, the drawings and the following description of exemplary embodiments of the invention.

characters

1 shows a simply configured embodiment of the device according to the invention.

2 shows a further embodiment of the present invention.

In 3 is a first housing part and a second housing part comprehensive embodiment of the device according to the invention shown.

4 shows a suitable for use with the device according to the invention sensor module with optoelectronic sensor and hose holder.

In 5a the sensor output (in V) determined in a test is shown as a function of the presence or absence of water in a plastic tube. 5b shows the temporal rate of change of the sensor output (in V / s) determined during a test.

6 shows a warning message that can be issued after the detection of liquid.

LIST OF REFERENCE NUMBERS

1

pump

2

Inlet of the pump for drawing in air

3

 Outlet of the pump for blowing out air

4

Connection for a suction line leading to the wound site

5

Vacuum connection

6

filter

7

Electronic control unit

8th

 Electronic fluid sensor

9

 Fluid receptacle

10

 Device for providing negative pressure

11

 Connection between pump and control unit

12

 Connection between liquid sensor and control unit

14

silencer

15

 wound site

16

 Air-impermeable wound cover

17

 Vacuum fitting (port)

18

 suction

20

 Device connected to a vacuum bandage to provide negative pressure

22

 power supply

23

 Touchscreen display

24

 connecting means

25

Body fluids extracted from the wound

26

 Inlet for feeding the body fluids

27

 Output for admission with negative pressure

30

 A device comprising a first housing part and a second housing part

31

 First housing part

32

 Second housing part

40

sensor module

1 shows a schematic representation of a device according to the invention 10 to provide negative pressure. The device comprises an electronic control unit 7 and an electrically driven or electrically driven pump 1 with an inlet 2 for intake of air and an outlet 3 for blowing out air. Furthermore, the device comprises a connection 4 , a filter 6 , a liquid sensor 8th as well as a vacuum connection 5 , The liquid sensor 8th communicates via the connection 12 with the control unit 7 , The control of the pump 1 through the control unit 7 takes place via the connection 11 , At the connection 11 and / or the connection 12 it can be an electrical connection or a wireless connection.

Negative pressure communication between wound site (in 1 not shown) and pump 1 can over the connection 4 getting produced. When connecting 4 For example, it is a common quick disconnect connector for plastic hoses. To establish a vacuum communication, a suction line 18 over the connection 4 with the vacuum connection 5 connected. The vacuum connection 5 , which is a vacuum communication between the inlet 2 the pump and the connection 4 allows exists at the in 1 shown embodiment of three sections, namely the section between terminal 4 and the filter 6 , the section between filters 6 and liquid sensor 8th as well as the section between liquid sensor 8th and pump 1 , The vacuum connection of a device according to the invention may comprise further sections, such as in 2 shown. The individual sections of the vacuum connection may comprise conduit means, for example plastic hoses. It is also possible to combine one or more of the named components in a single component. For example, the connection could 4 and the filter 6 be realized in a single component, so that no conduit means must be present between these elements.

2 shows a further embodiment of the device according to the invention in a schematic representation, wherein the reference numerals 20 designated device via the connection 4 connected to a vacuum dressing. The vacuum bandage includes an air-impermeable wound cover 16 , a vacuum fitting (port) 17 as well as the suction line 18 , The negative pressure bandage was at a wound site 15 created, with the wound site 15 includes the wound to be treated and the patient's intact skin surrounding the wound. In addition to the in 1 In the embodiment shown in FIG 2 apparatus shown a liquid receptacle 9 in which the body fluids sucked from the patient's wound 25 , preferably in liquid form. Inside the fluid receiving container 9 For example, areas formed by ribs or protrusions or chambers communicating with each other may be present, so that the collected body fluids are prevented from uncontrolled sloshing during a movement of the container. The liquid receiving container has an inlet 26 for feeding the body fluids and an outlet 27 to pressurize the container with negative pressure. Accordingly, the vacuum connection comprises 5 at the in 2 illustrated embodiment, a further portion, namely the interior of the liquid receiving container 9 , The exit 27 is in the upper region of the liquid receiving container 9 arranged.

Between containers 9 and the pump 1 is a filter as is conventional in the art 6 existing, which in the intact state, the penetration of liquid in the leading to the pump section of the vacuum connection 5 and further downstream. In case of a malfunctioning filter 6 in the direction of the pump 1 Being able to detect sucked liquid is between the filter 6 and the inlet 2 the pump 1 a liquid sensor 8th intended. A liquid passage through the filter can occur, for example, in a filter that has already been delivered defective manufacturer. Furthermore, it is possible for a filter to break through during operation. Finally, it would be conceivable that due to a faulty operation of the device by the user no filter was used at all. The electronic control unit 7 , which with the electronic liquid sensor 8th about the connection 12 (electrical or wireless) communicates, evaluates the sensor output from the liquid sensor 8th to be able to detect the ingress of liquid. Furthermore, the electronic control unit 7 about the connection 11 the pump 1 control (electrically or wirelessly). By the term "control" is meant here that the electronic control unit 7 start or stop the pump and regulate the speed of the pump. To control the vacuum operation by the electronic control unit 7 If appropriate, operating parameters of the pump could also be used, for example a tachometer signal output by the pump or the current consumption of the pump. Accordingly, over the connection 11 Also signals are exchanged in bidirectional direction. It is also conceivable, the electric pump 1 about the connection 11 at the same time to supply power, in which case an electrical connection is required.

In the case of detection of liquid by the liquid sensor 8th can the electronic control unit 7 the pump 1 deactivate to allow the fluid to be sucked in and, if necessary, to blow body fluids out through the outlet 3 into the interior of the device (and possibly also in the surroundings of the device). Alternatively or additionally, the control unit 7 to issue a warning signal (visual or audible) to the user on the defective filter 6 to point. Furthermore, the detected event in a to the electronic control unit 7 belonging memory (in 2 not shown). The electronic control units 7 Can with controls, especially with a touchscreen display 23 be connected. The user of the device can control the therapy device via the controls and program if necessary. Additionally, the electronic control unit may include interfaces (eg, a USB port) such that external electronic components, such as a portable computer, may communicate with the control unit 7 to be able to communicate. The interfaces are in 2 not shown. At the component 22 It is a power supply, which usually includes a rechargeable battery for the mobile operation of the device and a power supply. By means of the power supply 22 can the electrically driven or electrically driven pump 1 , the electronic control unit 7 as well as other electronic or electrical components such as the touchscreen display 23 be powered.

2 shows an optional silencer 14 , which to the outlet 3 the pump 1 connected to reduce the operating noise of the device. The silencer 14 may contain odor-absorbing substances, for example activated carbon, in order to avoid odor nuisance during operation of the device. At the in 2 As illustrated, the fluid system of the device extends from the port 4 to the downstream opening of the muffler 14 which communicates with the atmosphere. The fluid system of the device 20 in turn can be combined with the fluid system of patient-side components ( 16 . 17 . 18 ) communicate when the vacuum bandage over the port 4 is sealingly connected to the therapy device. Accordingly, then between the wound space of the patient and the opening of the muffler 14 made a coherent fluid system, wherein in the section between wound space and pump 1 during operation of the pump 1 a relative to the surrounding atmosphere reduced air pressure (negative pressure) is present. Fluids (especially wound secretions and air) will then travel downstream from the wound in the direction of the fluid receptacle as intended for use in the negative pressure therapy device 9 sucked.

3 shows a schematic representation of a further preferred embodiment of the device with a first housing part 31 and a second housing part 32 , The first housing part 31 includes in addition to the negative pressure generating electrically driven or electrically driven pump 1 the usually provided for repeated use components, ie in particular the liquid sensor 8th , the electronic control unit 7 , the power supply 22 and the touchscreen display 23 , Thus, the disposable components of the device, namely, liquid receptacles, can be used 9 with filter 6 as well as connection 4 (And any existing conduit between containers 9 and connection 4 ) are coupled to the intended for repeated use further components or separated from these.

Normally, the first housing part comprises 31 a housing in which or on which the aforementioned components are housed. The second housing part 32 forms the liquid receiving container 9 and may include other components, such as the connector 4 or alternatively one for connection 4 leading line (including the connection 4 ). The second housing part 32 is on the first housing part 31 the device manually fastened and from the first housing part 31 the device manually detachable. The detachable connection of the two housing parts ( 31 . 32 ) is preferably by means of a coupling agent 24 accomplished. This may be, for example, a snap-in and manually releasable by actuators locking. As in 3 shown is the filter 6 preferably immediately at the exit 27 of the liquid receiving container 9 appropriate. The filter 6 should be on his to the pump 1 side facing a suitable for producing a pressure-tight connection coupling element, for example, an annular seal, so that when joining the housing parts simultaneously a vacuum communication between the container and the pump-side portion of the vacuum connection 5 can be produced.

In 4 is a sensor module suitable for use with the device according to the invention 40 with optoelectronic sensor and hose holder shown. The optoelectronic sensor (in 4 not shown) is in the sensor module 40 integrated. The sensor module 40 can be either directly to the motherboard of the device, which also includes the electronic control unit 7 carries, be applied or alternatively connected by means of an electrical connection to the electronic control unit. In the sensor module 40 can one between filters 6 and inlet 2 the pump 1 arranged conduit portion which a portion of the vacuum connection 5 forms, be trapped. Sensor modules suitable for the device are commercially available (for example OPB350 sensor from OPTEK Technology Inc., USA).

5a shows by way of example the sensor output in volts determined in an experiment as a function of the presence or absence of water in a plastic tube. A higher output corresponds here to a higher light intensity measured at the sensor. For the experiment, a plastic tube made of silicone with an outside diameter of 10 mm and an internal diameter of 6 mm was clamped in the holder of an OPB350 OPTEK sensor. Shown is the sensor output measured in volts for a dry hose (sections ii and iv of the diagram) and for passing water through the hose (section iii) of the diagram). Section i shows the sensor output before the hose has been clamped. The diagram shows a very fast response of the sensor signal to the presence or absence of water in the hose. The rise or fall of the signal takes place in less than 200 milliseconds. The ratio of the sensor output when comparing states ii (dry) and iii (water) is about 2.5. The absolute sensor output is significantly influenced by the transparency (transmission) of the liquid present in the hose and by the material of the hose. In the experiment shown here, the sensor output first drops after insertion of the tube into the holder (sections i and ii) as the tube absorbs and scatters light. After passing through water, the sensor output increases because the water focuses the light beam. If there is a turbid fluid, such as blood, in the tubing, the sensor output will drop as compared to a dry tubing (in FIG 5 Not shown). When evaluating the sensor output, therefore, the transmission of the liquid to be detected must be taken into account. In particular, the transmission of the liquid to be detected must be taken into account when setting threshold values for the states "no liquid in the tube" or "liquid inlet". However, in a negative pressure therapy with different indications or even in the course of a single therapy a variety of fluids can be sucked out of the wound area, for example blood, purulent secretions or aqueous rinsing fluids (in instillation therapy). This can lead to difficulties in setting the above (absolute) thresholds. It is therefore more advantageous to carry out the interpretation of the sensor data on the basis of the temporal change of the sensor output (d (sensor output) / dt), it also being possible for additional absolute threshold values to be used. 5b shows by way of example the detection of liquid on the basis of temporal Rate of change of the voltage dU / dt measured at the sensor. Incidentally, the experimental setup corresponds to that at 5a shown situation. The measurement of the sensor output took place at intervals of 10 milliseconds.

Decisive for an error-free detection of liquid entry into the hose and to avoid false positive messages is the definition of a suitable threshold value for the rate dU / dt, for example in volts per second (V / s). For this purpose, the standard deviation σ of the values determined for the rate of change dU / dt was first calculated. The measurement was carried out using a dry tube. The threshold (dU / dt) is then obtained by multiplying the standard deviation σ by a suitable multiplication factor. The multiplication factor should be between 5 and 20 if possible. Preferably, the factor is 10 to 15, in particular 12 to 13.

In the present example ( 5b ), a standard deviation σ of 40.626 was determined by measuring the sensor fluctuation (dry tube). For this purpose, 1000 consecutive measured values were used (measurements were taken at a distance of 10 milliseconds). The threshold (dU / dt) = 500 V / s was therefore set as the threshold value for the detection of liquid entry into the hose. This value corresponds to 12.3 times the standard deviation σ.

In the in 5b the time window of the measurement has been exceeded, the threshold was exceeded after 70 milliseconds: Time (s) Rate of change dU / dt in V / s 0 -6.00 0.01 12,00 0.02 46,00 0.03 68,00 0.04 66,00 0.05 48,00 0.06 -6.00 0.07 -7,518.00 0.08 -13,166.00 0.09 -16,920.00 0.1 -18,828.00 0.11 -18,840.00 0.12 -16,964.00 0.13 -13,168.00 0.14 -7,502.00 0.15 -8.00 0.16 24.00 0.17 48,00 0.18 72,00 0.19 56,00 0.2 40,00 0.21 14.00 0.22 10.00 0.23 -26.00

The maximum rate of change dU / dt is -18840.00 V / s.

6 shows by way of example a warning message displayed on the touch screen of the negative pressure therapy unit, which according to a particularly preferred embodiment of the invention can be output upon a response of the liquid sensor. According to this embodiment, a sensor signal of the Liquid sensor for immediate shutdown of the pump, for issuing the warning message and for blocking the negative pressure therapy unit for the user. In the example of a warning message shown here, the event detected by the sensor is displayed to the user as a (technical) problem ("problem-detected"). Unlocking the vacuum therapy unit and canceling the warning message can only be accomplished by a service technician of the equipment manufacturer, not by the user himself. This is a precautionary measure designed to ensure that a device that may be contaminated with wound secretions is no longer being used and is being expertly reviewed. The appearance of the warning message on the touch screen should be combined with an audible warning to alert the user to the problem.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

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Claims (15)

On the body of a user portable and / or stationary device ( 10 . 20 . 30 ) for providing negative pressure for the negative pressure therapy of wounds on the human or animal body, comprising i) a vacuum generating electrically driven pump ( 1 ) with an inlet ( 2 ) for sucking in air, with an outlet ( 3 ) for blowing out air and having an interior which communicates with the inlet ( 2 ) and the outlet ( 3 ), (ii) a connection ( 4 ) for a suction line leading to the wound site ( 18 ), iii) a vacuum connection ( 5 ) between the connection ( 4 ) and the inlet ( 2 ), so that a vacuum communication between the pump ( 1 ) and the suction line leading to the wound site ( 18 ), iv) at least one filter ( 6 ), which is impermeable to liquids when intact, the filter ( 6 ) in the vacuum connection ( 5 ), v) an electronic control unit ( 7 ) for the pump ( 1 ), characterized in that the device ( 10 . 20 . 30 ) at least one electronic liquid sensor ( 8th ), which is connected to the control unit ( 7 ), wherein the at least one liquid sensor ( 8th ) downstream of the filter ( 6 ) is arranged. Contraption ( 10 . 20 . 30 ) according to claim 1, wherein the at least one liquid sensor ( 8th ) between the filter ( 6 ) and the inlet ( 2 ) of the pump, in the interior of the pump and / or in the region of the outlet ( 1 ) is arranged. Contraption ( 10 . 20 . 30 ) according to claim 1 or 2, further comprising a liquid receiving container ( 9 ) for receiving body fluids extracted from the wound, wherein the fluid receiving container ( 9 ) in the vacuum connection ( 5 ) between the filter ( 6 ) and the connection ( 4 ) for the suction line leading to the wound site ( 18 ) and wherein the liquid receiving container ( 9 ) at least one inlet ( 26 ) for feeding the body fluids and at least one outlet ( 27 ) for exposure to negative pressure. Contraption ( 10 . 20 . 30 ) according to claim 3, wherein the liquid receiving container ( 9 ) in its interior by ribs or projections formed areas or communicating with each other chambers, so that in the interior of the liquid receiving container ( 9 ) collected body fluids during a movement of the liquid receiving container ( 9 ) are prevented from uncontrolled sloshing. Contraption ( 10 . 20 . 30 ) according to one of the preceding claims 3 or 4, wherein the device comprises a first housing part ( 31 ) with the vacuum generating pump ( 1 ) and a second housing part ( 32 ), wherein the second housing part the liquid receiving container ( 9 ) and wherein the second housing part ( 32 ) on the first housing part ( 31 ) of the device ( 30 ) manually attachable and from the first housing part ( 31 ) of the device ( 30 ) is manually releasable. Contraption ( 10 . 20 . 30 ) according to claim 5, wherein in the first housing part ( 31 ) next to the pump the electronic control unit for the pump ( 1 ), a power supply ( 22 ) and means for operating the control unit ( 7 ) are accommodated by a user. Contraption ( 10 . 20 . 30 ) according to one or more of the preceding claims 3 to 6, wherein the filter ( 6 ) immediately at the exit ( 27 ) of the liquid receiving container ( 9 ) is arranged. Contraption ( 10 . 20 . 30 ) according to one or more of the preceding claims, wherein the electronic liquid sensor ( 8th ) is an opto-electronic sensor, a capacitive sensor or a conductive sensor. Contraption ( 10 . 20 . 30 ) according to claim 8, wherein the electronic liquid sensor ( 8th ) is an optoelectronic liquid sensor which can detect a transmission or refraction altered by a liquid. Contraption ( 10 . 20 . 30 ) according to claim 9, wherein the portion of the vacuum connection ( 5 ), which is located between the filter ( 6 ) and the inlet ( 2 ) is formed by a transparent tube and wherein the sensor ( 8th ) is attached to the outside of the transparent tube so that the presence of liquid in the tube is detectable by a change in transmission or refraction. Contraption ( 10 . 20 . 30 ) according to claim 10, wherein one through the optoelectronic sensor ( 8th ) measured change in transmission or refraction by the electronic control unit ( 7 ) then as liquid in the downstream of the filter ( 6 ) arranged portion of the vacuum connection ( 5 ) when a rapid increase or fall in the sensor output (measured as voltage or current) occurs, with a rapid increase or decrease indicating a change in the sensor ( 8th ) voltage or by the sensor ( 8th ) flowing current is understood by more than 10% per minute. Contraption ( 10 . 20 . 30 ) according to one or more of the preceding claims, wherein the electronic control unit ( 7 ) the pump ( 1 ) immediately after a detection of liquid which is downstream of the filter ( 6 ) has penetrated, can disable. Contraption ( 10 . 20 . 30 ) according to one or more of the preceding claims, wherein the device ( 10 . 20 . 30 ) additionally a liquid indicator for indicating and / or detecting liquid, which downstream of the filter ( 6 ) has penetrated. Use of an optoelectronic sensor ( 8th ) in a device ( 10 . 20 . 30 ) according to one or more of the preceding claims 9 to 13 for detecting liquid entry downstream of the filter ( 6 ) and / or the safety shutdown of the pump ( 1 ) and / or blocking the device and / or alerting a user. Use of an optoelectronic sensor ( 8th ) in a device ( 10 . 20 . 30 ) according to one or more of the preceding claims 9 to 13 for detecting liquid entry downstream of the filter ( 6 ) as part of a security check or maintenance of the device ( 10 . 20 . 30 ).

Images