Abstract:
The invention relates to a measurement apparatus for vacuum therapy system ( 60 ) for wound treatment, comprising an artificial wound unit ( 44 ) with a wall ( 43 ) that encloses an artificial wound cavity ( 45 ) open at least on one side, wherein passages for fluid are provided in the wall and can be supplied with a fluid via fluid delivery lines ( 46,80 ), and wherein the open side of the wound cavity ( 45 ) can be covered by a vacuum therapy system ( 60 ), wherein the vacuum therapy system ( 60 ) can apply a vacuum to the wound cavity ( 45 ) via a vacuum-generating device ( 90,92,100 ) of the measurement apparatus, and wherein a controllable heating device ( 39,40 ) is provided for regulating the temperature of the wound unit ( 44 ) and/or of the fluid.

Description:
This application is the national stage of PCT/EP2009/008959 filed on Dec. 15, 2009 and claims Paris Convention Priority of DE 10 2008 064 510.9 filed Dec. 22, 2008. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a measurement apparatus for vacuum therapy wound treatment systems comprising an artificial wound unit with a wall that encloses a wound cavity open at least on one side, wherein passages for fluid are provided in the wall and can be supplied with a fluid via fluid delivery lines, and wherein the open side of the wound cavity can be covered by a vacuum therapy system, wherein the vacuum therapy system can apply a vacuum to the wound cavity via a vacuum generating device of the measurement apparatus. 
     Such a device is known from US 2008/0077091 A1, which describes a system for testing vacuum wound dressings. It comprises a simulated wound with a housing and wound cavity within the housing. The shape and size of the cavity represents a particular wound type. A wound dressing can be placed over this wound cavity and a vacuum device applied to the wound cavity. Furthermore, at least one sensor is provided to acquire at least one parameter inside the simulated wound. Moreover, the provision of a fluid source for supplying fluids to the wound cavity is disclosed, which is intended to simulate wound exudates. The acquired data can then be evaluated using a computer and thus provide an indicator of how the system in question functions. Finally US 2008/0077091 A1 discloses a leakage model. 
     Osnabruck, 2006, a test is known that is used to examine wound dressings under vacuum conditions, wherein the measurement configuration requires the use of an ox heart or a real wound. 
     Other measurement apparatuses are already known, for example, from DE 102 26 532 B3, which describes a measurement apparatus for determining pressure values in plaster applications. Herein, a scar model is provided, wherein the measurement apparatus is used to determine pressure values of scar reduction plasters. However, such a measurement apparatus for scar reduction plasters is not suitable for checking wound dressings, as can be used in the case of weeping wounds, which produce wound exudate. 
     A further test apparatus is already known from GB 2 362 466 A, which, however, again does not disclose a device for testing vacuum therapy systems in wound treatment, but a system in which a wound dressing is placed in an artificial wound and artificial wound exudates are introduced into the wound and removed again via further outlets, wherein in this way the chemical composition, for example, of the wound exudates can be determined. 
     A disadvantage of said measurement apparatus for vacuum therapy systems here is that the wound environment can only be inadequately reproduced. The object of the invention is therefore to provide a measurement apparatus for vacuum therapy systems for wound therapy with which the natural wound environment can be better reproduced. 
     SUMMARY OF THE INVENTION 
     The invention achieves this object with a measurement apparatus with the characteristics of the independent claim, in which a controllable heating device for regulating the temperature of the wound unit and/or the fluid is provided. 
     By using a controllable heating device, the wound dressing to be tested can be tested under more realistic conditions by means of temperature regulation of the artificial wounds as well as the wound exudates supplied to the artificial wound, since a heated wound and preheated artificial wound exudate are closer to the real conditions of a wound than tests conducted at room temperature. In particular, more realistic wound situations can be simulated at a temperature that is closer to body temperature. 
     Unlike pure temperature measurement and execution of the tests in a temperature-controlled room, controllable heating of the wound unit and/or the fluid has the advantage of counteracting enthalpy of evaporation occurring during transition of wound exudates into the gaseous phase. This quantity of energy required for evaporation, which causes the fluid and the surroundings to cool down and which would otherwise influence the test conditions, can be countered by use of a controllable heating device. 
     Furthermore, the viscosity and evaporation rate of exudates depends on the temperature. The examination and adjustment of these parameters can be varied by means of the controllable heating device. 
     In this way, particularly realistic wound situations can be simulated. 
     Especially preferred is a controllable heating or water bath for regulating the temperature of the artificial wound and the fluid that is used as the artificial wound exudate. 
     In this case, use of vacuum therapy systems for wound therapy offers many advantages. The mechanical force that acts upon the cells means that wound healing is effected in the manner of compression therapy. The term vacuum therapy system thus comprises a wound dressing to be placed in or on the wound, a covering layer that is gas-tight and seals the wound, as well as a drainage tube to apply the vacuum and to remove wound exudates and, if applicable, rinsing fluid that is introduced. 
     Furthermore, a positive effect can be obtained by the continuous removal of wound exudates by means of the applied vacuum and microbial contamination in the wound can also be reduced. 
     The artificial wound unit can especially preferably be detachably and replaceably fixed on the measurement apparatus. For this, the measurement apparatus can have a receptacle for the artificial wound, wherein the receptacle, for example, can be constituted as a trough which is covered by a plate that holds the artificial wound. The heating bath can then especially preferably be disposed in the trough. 
     In particular, in this way, wounds of different sizes and geometries such as, in particular, tunneling wounds or large flat wounds and deep wounds can be simulated. The artificial wound units can all be connected to the available measurement apparatus and, in particular, inserted in the receptacle so that costs can be saved by using one measurement apparatus with different wound units. Furthermore, the response of vacuum therapy systems can be tested on different wound geometries and/or wound structures, such as, for example, large-area wounds as opposed to cavity wounds. Comparisons between a soft substrate, which can simulate tissue damage, and a hard substrate, which can simulate tissue damage down to the bone, can be made while keeping the other test parameters constant. 
     A force sensor is especially preferably provided in the wound cavity. The force sensor can be fixed in the artificial wound. With this force sensor, the force can be measured that is exerted on an artificial wound by the vacuum therapy system used in the test. The parameters that influence this force are both the deformability and nature of the wound and also the malleability of the wound dressing and, possibly, of the covering layer of the vacuum therapy system. Based on the force values determined, information can be obtained about the pressure conditions actually set in the wound cavity and therefore on a wound. This actual set pressure, which can be derived from the measured force, differs from the set vacuum (air pressure), which is applied to the wound by means of the vacuum therapy system and also differs from the vacuum set inside the wound cavity. 
     Furthermore, the wall of the artificial wound can be constituted by a material exhibiting open porosity. In particular, a glass material or glass body can be used that exhibits open porosity. Such glass frits are obtained during production of glass melts. 
     Use of a material exhibiting open porosity provides the advantage of particularly easy simulation of fluid conditions in a wound. In this way, the fluid, which is conveyed via the fluid delivery lines to the wall, can be distributed and released particularly homogeneously across the entire surface of the wall by capillary action. Homogenous release of fluid corresponds to the natural wound conditions. 
     The artificial wound can especially preferably be fixed in its receptacle in a mount and can be swiveled in the mount, wherein the position entered by swiveling can be locked or fixed. Locking or fixing can be possible either in any position or only in specified discrete positions. Because of the ability of the artificial wound to swivel, it is particularly easy to determine the absorption characteristics and drainage rates of exudates via a vacuum therapy system because the fluid distribution within the vacuum therapy system can be varied by these means. 
     Moreover, because of this ability to swivel, a wound can more easily be adjusted to represent, for example, the treatment of a wound on the leg of an in-patient in the recumbent position, while in the case of an out-patient, the wound is in the upright position for much of the day. This influences the distribution of exudates in the wound cavity and thus certain effects can be tested on the vacuum therapy system. 
     Especially preferred and inventive in its own right is the provision of a rinsing solution delivery line that is connected to the wound cavity. A rinsing solution, for example, a saline or Ringer&#39;s solution can be supplied via this rinsing solution delivery line. In this way, an additional therapy measure can be tested in addition to the application of a vacuum. Systems that feature a combined suction/rinsing facility can also be tested. Furthermore, the use of a rinsing solution can be provided without the use of a controllable heating device. 
     In particular, as an object in its own right, the invention relates to a measurement apparatus for vacuum therapy systems for wound treatment, comprising an artificial wound unit with a wall that encloses an artificial wound cavity, open at least on one side, wherein passages for fluid are provided in the wall and can be supplied with a fluid via fluid delivery lines, and wherein the open side of the wound cavity ( 45 ) can be covered by a vacuum therapy system, wherein the vacuum therapy system can apply a vacuum to the wound cavity ( 45 ) via a vacuum-generating device of the measurement apparatus, wherein the wound cavity can be connected to a rinsing solution delivery line through which a rinsing solution can be supplied to the same. 
     Furthermore, the influence of gravity on the vacuum therapy can be observed with a special mount. In particular, an artificial wound is provided, which is mounted such that it can swivel and which can be fixed in different positions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The invention is explained below using drawings. The figures show: 
         FIG. 1  A perspective view of the inventive measurement apparatus; 
         FIG. 2  A section through an inventive measurement apparatus; 
         FIG. 3   a  A plan view of the measurement apparatus with vacuum therapy system; 
         FIG. 3   b  A section through a measurement apparatus according to  FIG. 3   a  and 
         FIG. 4  A measurement apparatus in operation with connected vacuum unit. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a measurement apparatus with a mount  10  that is constituted as an aluminum cradle. Furthermore, the measurement apparatus comprises an artificial wound unit  44 , which is disposed in a receptacle  30  that comprises an aluminum trough  32  that is covered by a stainless-steel plate  34 . This constitutes a cavity  38  underneath the stainless-steel plate  34  and inside the trough  32 . The stainless-steel plate  34  can preferably be flat. 
     A seal  36  can be inserted between the stainless-steel plate  34  and the aluminum trough  32 , so that no fluid that may be provided in cavity  38  can escape in the region between the aluminum trough  32  and the stainless-steel plate  34 . 
     Furthermore, an artificial wound unit that is constituted by a glass frit and is designated by reference symbol  44 , is disposed at the center of the circular stainless-steel plate  34 , where it is contained in a housing  40 . The artificial wound unit  44  is sealed from the stainless-steel plate  34  by a seal  42  that is disposed between the housing  40  and the plate  34 . 
     The wound unit is mounted so that it can be swiveled in the mount  10 , wherein a clamping plate  20  is provided for this purpose, which enables the wound unit  44  to be locked in different discrete swivel positions around a swivel axis that is not depicted. The wound unit  44  can then be fixed in the preset position to enable continuous checking of a wound simulation in a particular position. 
       FIG. 2  shows the apparatus according to  FIG. 1  in section, wherein the artificial wound  44  can be supplied with fluid via a fluid delivery line  46 , and the fluid delivery line  46  is connected to a fluid reservoir, which is not depicted. Fluid, in particular, artificially manufactured fluid that imitates natural wound exudate is supplied to the artificial wound via the fluid delivery lines  46 , wherein an exudate distribution space  48  is provided beneath the artificial wound  44  for the even distribution of the fluid across the entire surface of the artificial wound  44 . 
     Because the artificial wound  44  is made of a glass frit exhibiting open porosity, an almost infinite number of fluid passages exist through which the fluid can enter the artificial wound cavity  45  from the wall  43 . 
     Moreover, sensors are provided, wherein a force sensor  52  is arranged in the glass frit in order to determine the force actually exerted on the base of the wound, and in addition, a pressure sensor  50  is provided, which is constituted outside the artificial wound  44  and is contained in the housing  40  and which is able to record the actual pressure inside the artificial wound. 
     Furthermore, a controllable heating device is provided in cavity  38 , wherein, in this case, the heating device is implemented as a controllable heating bath. The temperature of the heating or water bath  39  can be thermally regulated, so that the artificial wound  44 , but also the fluid that is supplied via the fluid delivery line  46  to the artificial wound  44 , is transferred through the temperature-controlled and regulated water bath and thus kept at a constant temperature. This compensates for effects that otherwise result from evaporation cooling in the wound cavity  45 . 
       FIGS. 3  show a corresponding embodiment with a fitted wound dressing as a vacuum therapy system for wound treatment. Herein, a wound unit  44 , different from that in  FIG. 2 , is provided, which simulates a flat wound. The vacuum therapy system for the wound therapy is here designated by reference symbol  60 . It comprises a wound dressing  61  as well as a cover  64  and a drainage tube  62 . A vacuum is applied to the vacuum therapy system  60  above the wound dressing  61  by means of a drainage tube  62 . Furthermore, a cover  64 , which is constituted as a polyurethane film, is placed over the wound dressing  61  and connects the drainage tube  62  to the wound dressing  61 , as far as possible without permitting leakage, and sealing it from its surroundings. The cover  64  is considerably larger than the wound dressing  61 , extends beyond it on all sides and is adhesively fixed to the stainless-steel plate  34 . If a vacuum is now applied via the drainage tube  62  to the wound dressing  61 , the correspondingly lower pressure is exerted on the artificial wound  44  with its wound cavity  45 , wherein the pressure conditions and the force conditions in the artificial wound  44  can be adjusted and measured by means of the sensors not depicted in  FIG. 3 . 
     Further,  FIGS. 3  a) and b) show a rinsing solution delivery line  120  for introducing a rinsing solution, for example, saline or Ringer&#39;s solution, into the wound cavity  45 . The introduced rinsing solution can then be removed from the wound  44  again by means of the drainage tube  62 . 
     In particular, the wound dressing  61  can be an absorbent wound dressing, wherein foams, but also wovens and nonwovens can be used. Cover  64  is a gas-tight film. 
     Finally,  FIG. 4  shows an embodiment of a measurement apparatus in operation with a connected vacuum generation unit. Herein, identical components are assigned the same reference symbols. Also depicted in  FIG. 4  is the controllable heating  70  for the heating bath  39 , which is disposed in cavity  38 . The temperature of the heating or water bath  39 , for example, is determined for the purposes of temperature control, for which a sensor  53  is provided. 
     Furthermore, as explained for  FIG. 2 , a force sensor  52  and a pressure sensor  50  are provided, which here are identified by the same reference symbol. 
     Artificial wound exudate is introduced into a cavity beneath the artificial wound  44  by means of the controlled wound exudate delivery line, which here is designated by the reference symbol  80  and corresponds to the delivery line  46  for artificial wound exudate (fluid) in the previous figures, and is distributed there evenly across the surface  47  of the artificial wound with cavity  48 . By means of the porosity of the glass frit, which here serves as the artificial wound  44 , wound exudate then enters the wound cavity into which, here, a multiple-layer wound dressing  61  of the vacuum therapy system  60  is inserted. The wound dressing  61  is held in position on the artificial wound by a covering layer  64 , which is fixed by adhesion to the measuring apparatus. The vacuum is applied to the wound dressing  61  via the drainage tube  62 , wherein the drainage tube  62  is routed through a collection tank  90  for wound exudates, in which the removed wound exudates can be collected. The drainage tube is attached to a vacuum generation device  100 , which here is constituted as a controlled vacuum pump and connected to a differential pressure sensor  101 . 
     When the vacuum is applied, the wound dressing  61  is pulled into the wound cavity  45  and much like compression therapy, a force is exerted on the woven when the vacuum is applied, which can be measured by the force sensor  52 . Furthermore, the applied pressure can be determined by the sensor  50 . 
     With the measurement device described above, an artificial wound  44  can be simulated particularly easily, which, in particular due to its ability to swivel, can represent different situations, such as, for example, a recumbent patient or an upright patient, but also regions with varying degrees of fluid accumulation. By using glass frit as the artificial wound  44 , an especially evenly distributed and thus realistic simulation of the excretion of wound exudates from a wound can be achieved. 
     Finally, by use of a heating bath  39 , the artificial wound  44 , but also the delivery line for wound exudate  46 ,  80  can be temperature-controlled, so that conditions such as they occur in the body of a human being or animal, can be simulated. Finally, the actual pressure conditions in a wound can be acquired by the provision of the force sensor  52 .