WO2011023384A1

WO2011023384A1 - Vacuum therapy device comprising a pressure sensor

Info

Publication number: WO2011023384A1
Application number: PCT/EP2010/005222
Authority: WO
Inventors: Dirk Baumann; Johannes Meyer
Original assignee: Vcs Medical Technology Gmbh
Priority date: 2009-08-29
Filing date: 2010-08-25
Publication date: 2011-03-03
Also published as: DE102009039336A1; DE102009039336B4

Abstract

A vacuum therapy device comprising a wound cover (21) which covers the wound (3) in an air-tight manner and a suction pump (10) for producing a negative pressure on the wound (3), said suction pump communicating with the wound cover (21) via a vacuum line (8). The device further comprises at least one pressure sensor (18, 19, 20) for determining the negative pressure on the wound (3) and a controller unit (19) for controlling the negative pressure. In order to increase the accuracy of measurement of the measured negative pressure, the pressure sensor (18, 19, 20) is arranged in the region of the wound (3) inside or directly on the wound covering (21, 7) and is protected from the contact with liquid (6) by a flexible protective membrane (32, 39).

Description

Vacuum therapy device with pressure sensor

The present invention relates to a vacuum therapy device with a wound covering a wound airtight, a

Suction pump, which communicates via a vacuum hose with the wound cover to generate negative pressure at the wound, with at least one pressure sensor for determining the negative pressure at the wound and with a control unit for controlling the negative pressure.

Such a vacuum therapy device is known from DE 10 2005 014 420 A1. In the known vacuum therapy device designed as a strain gauge pressure sensor is within the

Wound cover arranged. However, the strain gauge allows only very rough, qualitative pressure measurements. More sensitive and accurate pressure sensors can not be used in the known device because they are damaged by the contact with the wound fluid or at least no longer provide reliable readings.

In order to regulate the desired negative pressure at the wound as precisely as possible and keep it constant, one needs reliable and reproducible pressure measurements. With little effort, you can attach a pressure sensor in a control unit of the vacuum therapy system in the vicinity of the suction pump. However, this has the disadvantage that the location of the pressure measurement is relatively far away from the location of the wound, wherein the distance is bridged by a vacuum hose. As long as the suction pump is working, air closes through the vacuum hose and there is a pressure gradient due to the flow resistance of the vacuum hose. A pressure gradient arises also with further

Device elements in the region between the pressure sensor and the wound, in particular a container for receiving wound exudate, an existing filter or in the area of a wound dressing. If the resistance is known and remains unchanged, you could from the pressure applied to the pressure sensor on the wound

close prevailing negative pressure. However, since the flow resistance can change, in particular by buckling of the vacuum hose or blockages by wound exudate, can no longer be reliably closed at a pressure remote from the wound pressure sensor on the pressure at the site of the wound. It has therefore already been proposed to switch off the suction pump for the period of measurement and to make the measurement after pressure equalization. If no air flow is present in the suction path, in particular in the vacuum hose, an equilibrium state arises, so that the negative pressure at the wound and the negative pressure measured by the pressure sensor are substantially the same. However, this method has the disadvantage that the pressure in the entire system steadily increases and approaches the atmospheric pressure, because there are usually air leaks.

In EP 0 865 304 it is proposed to provide a second hose between the wound and the pressure sensor accommodated in the apparatus in the vicinity of the suction pump. This second hose is not used for suction, so that no air flow forms in him and the existing air is balanced by pressure equalization. As a result, the values measured by the pressure sensor are much closer to the negative pressure at the site of the wound. However, this known device has the disadvantage that an additional relatively long hose is provided. This is not only technically complex and costly, but may be less comfortable for the patient than a single tube. In addition, the risk of accidents is increased, for example, by entangled or by kinked

Hoses. The object of the invention is to provide a vacuum therapy device of the type mentioned in terms of measurement accuracy for the

To improve negative pressure at the site of the wound.

The solution according to the invention therefore provides that the pressure sensor in the area of the wound is arranged inside or directly on the wound cover and is protected from contact with liquid by a flexible protective membrane. The small distance between the pressure sensor and the wound increases the accuracy of the

Vacuum measurement, wherein the protective diaphragm deterioration of the accuracy of measurement due to contact of the sensitive

Sensor electronics with the wound fluid avoids.

Preferably, the protective membrane consists of a thin

Plastic film. Such a plastic film seals the pressure sensor from its environment liquid-tight and yet is so resilient that it no resistance to the air with changes in the negative pressure

and thus ensures that the same pressure prevails on the pressure sensor side of the plastic film as in the outer area.

In an advantageous embodiment of the invention, the pressure sensor with a radio transmitter for transmitting measurement signals to the

Control unit provided. This measure allows the accommodation of the pressure sensor below the wound cover, without the

Measuring signals must be transmitted by means of an electrical line to the control unit. As a result, the disadvantages associated with an electrical line, in particular problems of airtight passage through the wound cover and the additional

Susceptibility to interference in the area between wound cover and control unit avoided. - A -

In a development of the invention, it is provided that the pressure sensor is provided with an RFID chip. Such an RFID chip can be activated by a transmission pulse from the control unit and then sends back itself a signal with which the measured pressure values are coded. The signal emitted by the chip is received by the control unit, whereby the print data is transmitted. The RFID chip has the advantage that it manages without its own power supply.

If the pressure sensor is arranged in the interior or on a wound-facing outside of a wound dressing arranged between the wound and the wound cover, the distance to the wound is advantageously so low that the measurement can be carried out with the utmost accuracy. Another advantage of this measure is that the pressure sensor can already be incorporated during production of the wound dressing, so that no separate installation of the pressure sensor on the patient is required.

In a first preferred embodiment of the invention, the pressure sensor is completely enclosed by the protective membrane. This embodiment is particularly recommended in combination with an RFID chip, which is small enough to be welded together with the pressure sensor in a tiny bag made of plastic film, wherein the plastic film serves as a protective membrane.

In a second alternative embodiment of the invention, the pressure sensor is arranged in a liquid-tight sensor housing which is closed by the protective membrane. Such

Sensor housing has the advantage that it is more robust and can protect the pressure sensor against strong external pressure or impact. The protective membrane can also be found inside the

Sensor housing located in a protected place. In a further development of the last-mentioned embodiment, it is proposed that the sensor housing be connected to one for the connection of the

Vacuum hose certain hose adapter of the wound cover is arranged. The attachment to the hose adapter has the advantage that it can be done during the manufacture of the hose adapter, so that the pressure sensor is installed without a further step together with the hose adapter over the wound of the patient. The installation of the pressure sensor can therefore not be forgotten.

In addition, it is made of relatively strong material

Hose adapter especially good for firmly attaching the pressure sensor. This embodiment is also well suited for pressure sensors, which must be connected by means of an electrical line to the control unit, because at the hose adapter leading to the control unit vacuum hose is connected anyway. A parallel guidance of vacuum hose and electrical line is therefore appropriate.

The invention can be further improved by the

Sensor housing is integrally formed with the hose adapter. In particular, the hose adapter may consist of a plastic injection-molded part. In the manufacture of the hose adapter, therefore, the sensor housing can be formed as a cavity in the hose adapter, without requiring a special manufacturing step for this purpose.

When the sensor housing penetrates through the protective membrane of the

Pressure sensor separated, only via a through hole with the

Having outer region associated housing portion, the air through the passage opening unhindered access to the protective membrane, wherein the protective membrane in the interior of said housing portion

is largely protected from destruction by mechanical action from the outside. In a further embodiment of the invention, it is provided that a sensor tube is attached to the passage opening, which projects into the wound base or the interior of a wound dressing arranged between the wound and the wound cover. This sensor tube has the task of any flow resistance between the wound base and the

To avoid or bypass the pressure sensor, so that the pressure sensor is exactly the pressure that prevails at the free end of the sensor tube. It does no harm if some wound fluid should enter the sensor tube, as there is basically no air flow in the sensor tube. Even if some wound fluid in the

Sensor tube should be penetrated, this can not s.den

Pressure sensor itself, because it is prevented by the protective membrane. On the other hand, the wound fluid, like a hydraulic system, transmits changes in the negative pressure, so that the

Pressure sensor nevertheless always essentially the same negative pressure prevails as at the end of the sensor tube.

Embodiments of the invention will be explained in more detail with reference to the drawing. The figures of the drawings show in

Single: Figure 1: a schematic representation of an inventive

Vacuum therapy device with pressure sensor in the area of the wound;

Figure 2: a hose adapter with connected

Vacuum hose in a perspective view; Figure 3: an enlarged sectional view of the hose adapter with installed pressure sensors in a first

Design shape; Figure 4: a representation like Figure 3, but another

Design shape;

Figure 5: a sectional schematic representation of a

Pressure sensor in a first embodiment; FIG. 6: a sectioned schematic representation of a

Pressure sensor in a second embodiment;

Figure 7: a sectional schematic representation of a

Pressure sensor in a third embodiment.

FIG. 1 shows a section of a tissue 1 of a patient in section. At the skin surface 2, a wound 3 forms a depression which extends to the wound base 4. The depression in the wound 3 is filled with a wound pad 5 made of foam, fleece or

Fabric material can exist. In any case, the wound dressing 5 is suitable for exerting mechanical pressure on the wound 3 and for taking up the wound exudate 6 emerging from the wound 3. On the

Wound pad 5, a hose adapter 7 is arranged, on which a

Vacuum hose 8 is attached. The vacuum hose 8 connects the hose adapter 7 with a container 7, in which the

Wound exudate 6 is collected. The container 9 is over a

Connecting line 12 is connected to a suction pump 10, which is driven by an electric motor 11. A control unit 13 comprises input means 14, in particular an input keyboard and

Display means 15, for example an LCD display for displaying the operating conditions. Furthermore, the control unit 13 includes a controller 16 for controlling the electric motor 11 of the suction pump 10 via a control line 17th For the measurement of the negative pressure to be regulated at the site of the wound, a pressure sensor 18, 19, 20 is provided which, as shown in FIG. 1, can be arranged at various points in the area of the wound 3. For airtight covering of the wound 3, a wound cover 21 is provided. Which is glued in its outer edge region 22 airtight on the skin surface 2. The wound cover 21 is provided in its center with an approximately circular hole through which the

Hose adapter 7 protrudes.

As best seen in Figure 2, the hose adapter 7 consists of an upper part 23 and a lower part 24, on which the upper part 23 is engaged. At the top 23 of the vacuum hose 8 is attached. The lower part 24 has a disk-shaped central portion 25, from which, starting from the four support portions 26 at uniform angular intervals of 90 ° to each other radially outwardly. The support sections 26 of the tube adapter 7 rest on the wound dressing 5 and press it under the action of negative pressure against the wound base 4. On the upper side of the central section 25, the wound cover 21 is glued airtight. When the electric motor 11 in the suction pump 10 is started, the suction pump via the connecting line 12 sucks the air first from the container 9 and the vacuum hose 8 through the hose adapter 7 also from the space above the wound 3 and below the wound cover 21st out. A value for the negative pressure is measured by the pressure sensor 18, which is connected via a signal line 27 to the controller 16 of the control unit 13. Alternatively, the pressure sensor 19 may be connected via the signal line 27 to the controller 16.

In a further embodiment, the pressure sensor 20 is connected to an RFID chip in a tiny unit and either inside the wound dressing 5 or on one of the wound 3 facing outside - Q - the wound dressing 5 on wound base 4 arranged. The control unit 13 is equipped with an antenna 28, which radio signals 29

sending out. The radio signals 29 are from the RFI D chip of the

Pressure sensor 20 received. The pressure sensor 20 then transmits radio signals 30 encoded with the measured pressure. The radio signals 30 reach the antenna 28 of the control unit 13, where they are decoded and forwarded to the controller 16. In this way, the controller 16 receives information about the pressure measured at the site of the wound by the pressure sensor 20 and then controls the

Electric motor 11 of the suction pump 10 in order to approximate the measured actual pressure to a predetermined target pressure. The desired pressure can be predetermined for example via the input keyboard 14 or via a data memory by means of a microprocessor, not shown.

Information about the processes in the control unit 13, the user can be found on the display 15.

As best seen in Figures 5 and 6, the pressure sensor 18, 19 housed in a sensor housing, which of a

Protective membrane 32 in two housing sections 33, 34 is divided. The protective membrane 32 seals the provided with the actual pressure sensor 18, 19 housing portion 33 airtight. The other

Housing section 34 is connected via a passage opening 32 with the outside area in connection, so that the negative pressure in the outer area can be measured. In this case, the protective membrane 32 is so flexible designed that it prevails in the housing section 34 pressure on the

Housing section 33 transmits, without that on their am

Sensor housing 31 airtight edge portions attached any forces on the sensor housing 31 transmits.

As best seen in FIG. 3, the pressure sensor 18 shown in detail in FIG. 5 can be located either on the upper part 23 or on the lower part 24 be attached to the hose adapter 7. The hose adapter 7 is assigned to the wound cover 21 in the sense of the invention and is considered here as part of the wound cover 21.

When attaching the pressure sensor 18 on the outside of the upper part 23 of the hose adapter, the upper part 24 is provided with a pressure channel 36, through which the negative pressure from the interior of the wound 3 and under the wound cover 21 with the pressure sensor 18 in

Connection stands. When attaching the pressure sensor 18 on the inside of a support portion 26 of the tube adapter 7 no special pressure channel is required because the through hole 35 communicates with the space below the wound cover 21st

Instead of attaching a separate sensor housing 31 to the hose adapter, the hose adapter itself may have a cast-in

Have cavity in which the pressure sensor 18 and the protective membrane 30 are arranged.

FIGS. 4 and 6 show another embodiment of the invention

Pressure sensor 19 according to the invention shown in which the

Through opening 35 of the sensor housing 31 with a

Sensor tube 37 is provided, which, as can be seen in Figure 1, protrudes into the interior of the wound dressing between wound 3 and wound cover 21 21. Alternatively, the sensor tube 27 can also protrude to the wound base 4. At its free end 38 is the

Sensor tube 37 is open and communicates with the prevailing at the open end 38 negative pressure. As is not pumped through the sensor tube 37, no fluid flows there. Therefore, there is a perfect pressure equalization between the negative pressure prevailing at the free end 38 and the voltage applied to the pressure sensor 19 Vacuum, so that the sensor 19 can actually measure the negative pressure at the free end 38 of the sensor tube 37.

For a wireless signal connection between the pressure sensor 20 and the control unit 13 is best shown in Figure 7

Embodiment of the pressure sensor 20 suitable. The connected to an RFID chip pressure sensor 20 is there welded into a thin plastic film 39, which protects him as a protective membrane 39 from all sides

liquid-tight and airtight encloses. The pressure sensor 20 can thus be arranged without difficulty in the interior of the wound dressing 5 or on the underside of the wound dressing 5 in the vicinity of the wound base 4, without the wound exudate 6 being able to restrict or destroy the function of the pressure sensor. Especially practical is the

Fact that no signal line to connect to the

Control unit 13 is required. Rather, the

Signal transmission via radio using the antenna 28 of the control unit 13.

LIST OF REFERENCE NUMBERS

1 tissue

2 skin surface

3 wound

4 wound ground

5 wound dressing

6 wound exudate

7 hose adapter

8 vacuum hose

9 containers

10 suction pump

11 electric motor

12 connection line

13 control unit

14 input means

15 display means

16 controllers

17 control line

18 pressure sensor

19 pressure sensor

20 pressure sensor

21 Wound coverage

22 border area

23 shell

24 lower part

25 central section

26 support section

27 signal line

28 antenna 29 radio signal

30 radio signal

31 sensor housing

32 protective membrane

33 housing section

34 housing section

35 passage opening

36 pressure channel

37 sensor hose

38 Free end

39 Protective membrane / plastic film

Claims

1. Vacuum therapy device with one wound (3) airtight

covering wound cover (21), a suction pump (10), which communicates via a vacuum hose (8) with the wound cover (21) in order to generate negative pressure at the wound (3), with at least one pressure sensor (18, 19, 20 ) for determining the negative pressure at the wound (3) and with a control unit (13) for controlling the negative pressure, characterized in that the pressure sensor (19, 20) in the region of the wound (3) within or directly on the wound cover (21, 7) arranged and by a

flexible protective membrane (32, 39) before contact with

Liquid (6) is protected.

2. Vacuum therapy device according to claim 1, characterized

characterized in that the protective membrane (32, 39) consists of a thin plastic film.

3. Vacuum therapy device according to claim 1 or 2, characterized

in that the pressure sensor 20 is provided with a radio transmitter for transmitting measurement signals to the control unit.

4. Vacuum therapy device according to claim 3, characterized

characterized in that the pressure sensor (20) is provided with an RFID chip.

5. Vacuum therapy device according to one of the preceding

Claims, characterized in that the pressure sensor (20) in the interior or on one of the wound (3) facing outside of a wound (3) and wound covering (21) arranged wound dressing (5) is arranged.

6. Vacuum therapy device according to one of the preceding

Claims, characterized in that the pressure sensor (20) of the protective membrane (39) is completely enclosed.

7. Vacuum therapy device according to one of claims 1 to 5,

characterized in that the pressure sensor (18, 19) in a liquid-tight sensor housing (31) is arranged, which is closed with the protective membrane (32).

8. Vacuum therapy device according to claim 7, characterized

in that the sensor housing (31) is attached to a hose adapter intended for the connection of the vacuum hose (8)

(7) of the wound cover (21) is arranged.

9. Vacuum therapy device according to claim 8, characterized

characterized in that the sensor housing is designed in one piece with the hose adapter (7).

10. Vacuum therapy device according to one of claims 7 to 9,

characterized in that the sensor housing (31) extends through the protective membrane (32) from the pressure sensor (18, 19)

separated, only via a through hole (35) with the

Outside housing connected housing portion (34).

11. Vacuum therapy device according to claim 10, characterized

characterized in that at the passage opening (35) a

Sensor tube (37) is mounted, which extends into the wound base (4) or in the interior of between wound (3) and wound cover (21) arranged wound dressing (5).