Abstract:
A method for cleaning a surgical instrument with a cleaning fluid, the surgical instrument having at least one channel. The method including: applying a pressure to the cleaning fluid, flushing the channel by means of the cleaning fluid, and varying the pressure during the flushing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a continuation of PCT/EP2014/002012 filed on Jul. 23, 2014, which is based upon and claims the benefit to DE 10 2013 216 532.3 filed on Aug. 21, 2013, the entire contents of each of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present application relates to a method for cleaning a surgical instrument having at least one channel, such as an endoscope, by means of a cleaning fluid. The present application furthermore relates to a device for cleaning a surgical instrument having at least one channel, such as an endoscope, by means of a cleaning fluid. The present application further relates to a use. 
         [0004]    2. Prior Art 
         [0005]    In the prior art, flexible endoscopes with internal channels are known that for example are used in gastrointestinal surgery. To clean such endoscopes, the internal channels are generally flushed with a cleaning medium under constant pressure with an unchanging volumetric flow. 
         [0006]    To remove encrusted particles and particles jammed within the channel, for example a complicated pretreatment is carried out in which the endoscope, or respectively the channels, are manually brushed. 
         [0007]    In this regard, methods have been developed in which air and water are alternatingly pumped through the channels. Furthermore, the so-called two-phase flow technique is known in which very fine droplets of fluid in a gas phase produce the same result as manual brushing. 
         [0008]    The known methods for avoiding manual brushing have the disadvantage that corresponding cleaning devices must have additional components for the air supply and air passages and are correspondingly more complex and error-prone than simple flushing devices. 
         [0009]    Furthermore, such prior art methods are only slightly suitable for removing so-called biofilms where there is an extensive and cohesive contamination of the endoscope channel. Removing such substances is infeasible, or is only feasible with very long processing times. 
       SUMMARY 
       [0010]    Based on this prior art, an object is to simplify the cleaning of an endoscope with an endoscope channel, such as improving the removal of a biofilm from an endoscope channel interior. 
         [0011]    This object is achieved by a method for cleaning a surgical instrument having at least one channel, such as an endoscope, by means of a cleaning fluid, comprising the following procedural steps: 
         [0012]    applying a pressure to the cleaning fluid, 
         [0013]    flushing the channel by means of a cleaning fluid, and 
         [0014]    varying the pressure during flushing. 
         [0015]    Varying the pressure exerted on the cleaning fluid, or varying the pressure within the cleaning fluid, especially within the channel, such as in the endoscope channel, causes in particular deformations of the channel, whereby the channel expands when the pressure is increased and contracts when the pressure is reduced. By means of the deformations, contaminants adhering to the inner wall of the channel are released and can thereby be flushed more easily out of the channel with the cleaning fluid. 
         [0016]    An advantage of such method is that biofilms and other extensive contaminants can also be released and flushed out. 
         [0017]    Overall, the cleaning result is thereby improved, and the duration of cleaning is shortened. 
         [0018]    In addition, another advantage of the shorter cleaning duration is that less cleaning fluid is used. This renders cleaning more economical and environmentally friendly. 
         [0019]    The pressure can be repeatedly varied during flushing which further improves the cleaning effect. 
         [0020]    Furthermore, the pressure can be varied repeatedly at regular intervals in time, which can be a periodic, cyclical or oscillating variation of the pressure. This has the advantage of technically easy implementation, such as being based on rotating drive machines with corresponding pressure actuators. 
         [0021]    Pressure can be applied to the cleaning fluid using a cyclical pump device, which can be a pump device or a delivery apparatus which, due to the design, has several work cycles or work phases such as a suction cycle and a compression cycle, or an ejection cycle. A pulsating or oscillating pressure level can thereby be directly generated in the delivered or pumped cleaning fluid. Such a cyclical pump device ican be a reciprocating pump or a diaphragm pump. 
         [0022]    A diaphragm pump has the further advantage that it does not have a brush seal which also makes a corresponding cyclical pump device suitable for delivering contaminated cleaning fluid. 
         [0023]    Suitable diaphragm pumps are offered by KNF FLODOS AG, Sursee, Switzerland under the product name of NF 600 or NF 1.600, as well as by Eckerle lndustrie-Elektronik GmbH, Malsch, Federal Republic of Germany under the product name of CDP 6800, CDP 8800, DDP 5800 or DDP 550. 
         [0024]    Checking the cleaning of the canal can comprises another procedural step of such method. 
         [0025]    Checking the cleaning can involve a test of the extent to which cleaning was successful, or must be continued or repeated. The test can be carried out by determining a flow rate and/or by determining a pressure drop within the channel. 
         [0026]    A constant pressure can be applied to the cleaning fluid during the cleaning check. In general, this allows more precise measuring results or cleaning results to be achieved. 
         [0027]    The method can also be suitable for cleaning endoscope accessories and accessories for endoscope cleaning apparatuses, such as hoses, etc. 
         [0028]    An underlying objective is furthermore achieved with a device for cleaning a surgical instrument having at least one channel, such as an endoscope, by means of a cleaning fluid, comprising a pump apparatus for the cleaning fluid and a connection, wherein the pump apparatus can be configured to apply a varying pressure to the cleaning fluid while flushing the channel. 
         [0029]    To apply a varying pressure to the cleaning fluid, the pump apparatus of a cleaning device can comprise a cleaning apparatus, such as a cyclical pump device, such as a reciprocating pump or a diaphragm pump. 
         [0030]    The channel to be cleaned can consist of a flexible material. The endoscope can be a flexible endoscope. 
         [0031]    Alternatively, the pump apparatus can comprise a continuous pump device such as an automatic control device for changing an output pressure of the continuous pump device. 
         [0032]    A continuous pump device can be a pump device or delivery device with a continuous, such as non-cyclical, delivery. A varying or variation in the pressure or output pressure of the continuous pump device can be achieved by varying the pump or delivery rate by means of the control device. This can be accomplished automatically. 
         [0033]    A suitable continuous pump device can be a reciprocating pump with an electric drive operated by alternating current, wherein the control device can comprise a frequency converter which is located upstream from the electric drive for the alternating current. In this case by changing the frequency of the alternating current, the rotational speed of the reciprocating pump, and correspondingly its delivery rate and hence the output pressure, can be varied. 
         [0034]    The pump apparatus can comprise at least two pump apparatuses, wherein one of the pump devices can be configured as a cyclical pump device, and another pump device can be configured as a continuous pump device. 
         [0035]    The advantages of a continuous pump device, such as a high delivery rate per unit time is thereby synergistically combined with the advantages of a cyclical pump device, such as a design-based variation of the output pressure. 
         [0036]    Furthermore, the volumetric capacity of the cleaning fluid and the variation of the pressure within the cleaning fluid, such as the amplitude and frequency of the pressure variation, can be set independent of each other in that the respective delivery rate of the continuous pump apparatus on the one hand, and the cyclical pump device on the other hand, are suitably adjusted. 
         [0037]    The device can comprise a connection group with a plurality of connections for one channel each, such as an endoscope channel. 
         [0038]    This further reduces the duration of cleaning a surgical instrument because a plurality of channels of the surgical instrument can be cleaned at the same time. 
         [0039]    The device can comprise a plurality of connections or connection groups, wherein the pump apparatus can comprise at least one pump device which is exclusively assigned to one connection or connection group. 
         [0040]    This yields great flexibility in operating the device because the pressure level of this connection, or respectively this connection group, can be set independent of other connections and connection groups by means of the pump device assigned exclusively to one connection or connection group. 
         [0041]    A connection or connection group can comprise a control device for checking the cleaning of channels connectable to the connection or connection group, such as by means of determining a flow rate and/or by means of determining a pressure drop in the channel. 
         [0042]    For this purpose, the control device can have a pressure sensor for determining a pressure of the cleaning fluid, and/or a flow sensor for determining the flow volume or flow rate. 
         [0043]    An object is furthermore accomplished using a cyclical pump device, such as a diaphragm pump, and a continuous pump device, such as a reciprocating pump, for cleaning a channel of a surgical instrument, such as an endoscope channel. 
         [0044]    Further characteristics will become apparent from the description of the embodiments together with the claims and the included drawings. Embodiments can fulfill individual characteristics or a combination of several characteristics. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0045]    The embodiments are described below, without restricting the general idea of the invention, using exemplary embodiments with reference to the drawings, whereby we expressly refer to the drawings with regard to all details that are not explained in greater detail in the text. 
           [0046]    In the figures: 
           [0047]      FIG. 1 a    schematically illustrates the removal of a contaminant particle from an endoscope channel by flushing with the cleaning fluid; 
           [0048]      FIG. 1 b    schematically illustrates the removal of a biofilm from an endoscope channel by flushing with the cleaning fluid; 
           [0049]      FIG. 2  schematically illustrates a pressure profile of a cleaning fluid in an endoscope channel during a cleaning process; 
           [0050]      FIG. 3 a    schematically illustrates the functioning of a diaphragm pump (suction cycle); 
           [0051]      FIG. 3 b    schematically illustrates the functioning of a diaphragm pump (discharge cycle); and 
           [0052]      FIG. 4  schematically illustrates an example of a cleaning and disinfecting device. 
       
    
    
       [0053]    In the drawings, the same or similar elements and/or parts are provided with the same reference numbers in order to prevent the item from needing to be reintroduced. 
       DETAILED DESCRIPTION 
       [0054]      FIG. 1 a  and 1 b    schematically illustrate a section of an endoscope channel  30  which is bordered on the side by a side wall  32 , which can be flexible. The side wall  32 , or respectively, the endoscope channel  30 , has an inner surface  34 . 
         [0055]    The endoscope channel  30  is closed in the peripheral direction, for example because the side wall  32  is configured in the shape of a hose. This is not shown in  FIG. 1 a    for reasons of clarity. 
         [0056]    In  FIG. 1   a,  a contaminant particle  40  adheres to the inner surface  34  of the endoscope channel  30  which is to be removed by flushing the endoscope channel  30  with a cleaning fluid. A flow profile  50  of the cleaning fluid is also schematically illustrated in  FIG. 1 a    which represents the flow speed  51  of the cleaning fluid depending on the distance  52  from the inner surface  34  at a randomly selected point in the longitudinal direction of the endoscope channel  30  at a randomly selected time. 
         [0057]    The contaminant particle  40  has an effective contact surface  44  upon which the flow of cleaning fluid acts. Shearing forces are thereby exerted on the contaminant particle  40 . 
         [0058]    When the flow of cleaning fluid contacts the surface  34  of the endoscope channel  30  in front of the contaminant particle  40 , a boundary layer between the contaminant particle  40  and surface  34  is stressed by the shearing forces. This causes the contaminant particle  40  to release from the surface  34 , wherein the released contaminant particle  40  is carried away with the flow of cleaning fluid and flushed out of the endoscope channel. 
         [0059]    The greater the shearing forces, the faster and more completely the contaminant particle  40  is released from the inner surface  34  of the side wall  32 , wherein the shearing forces are further reinforced when a swirling of the cleaning fluid occurs at the contaminant particle  40 . 
         [0060]      FIG. 1 b    schematically illustrates the endoscope channel  30  from  FIG. 1 a    with contamination in the form of a biofilm  42 . The biofilm  42  is an extensive, closed layer of contamination on the inner surface  34  of the side wall  32  of the endoscope channel  30  which for example has a viscous to slimy consistency. 
         [0061]    The biofilm  42  has a much smaller effective contact surface  44  than an isolated contaminant particle  40 , and a substantially laminar flow flows over it. The effective contact surface  44  does not extend to the inner surface  34  of the side wall  32  and is limited to the top layers of the biofilm  42  at a distance from the surface  34 . 
         [0062]    Consequently, only the surface of the biofilm  42  is contacted by cleaning fluid at a constant pressure and volumetric flow in conventional flushing, and is at best removed in layers, and is therefore insufficiently removed, or only after a very long time of flushing. 
         [0063]    A varying pressure is applied to the cleaning fluid in the endoscope channel  30 . An example of a pressure profile  60  is schematically illustrated in  FIG. 2 . The pressure profile  60  presents a pressure  61  of the cleaning fluid in the endoscope channel depending on the time  62 . 
         [0064]    The pressure profile  60  has for example recurring periods  64  which each comprise a low pressure phase or a low pressure cycle A and a high-pressure phase or a high pressure cycle B. The pressure  61  which varies over time of the cleaning fluid in the endoscope channel  30  leads to elastic deformations, or deformations of the side wall  32  of the endoscope channel  30 , which can be a flexible side wall. The endoscope channel  30  expands when a low-pressure phase B switches to a high-pressure phase A, and contracts when a high-pressure phase B switches to a low pressure phase A. 
         [0065]    The difference in pressure between a high pressure phase and a low-pressure phase can be set such that the direction of flow of the flushing agent in the endoscope channel  30  is always retained when switching between the high-pressure phase to the low-pressure phase and vice versa. 
         [0066]    The repeated deformations of the side wall  32  cause a significantly faster and more complete release of the biofilm  42  from the surface  34  of the endoscope channel  30  than would be possible solely due to the shearing forces acting on the biofilm by means of the flowing cleaning fluid. 
         [0067]    This can be achieved by any pressure profile  60  with pressure  61  changing over time, such as by individual pressure surges at an irregular sequence over time as well. 
         [0068]    The pressure profile  60  can be realized by means of a diaphragm pump  70 . 
         [0069]      FIGS. 3 a  and 3 b    schematically illustrate the functioning of a diaphragm pump  70 . 
         [0070]    The diaphragm pump  70  comprises a housing with a pump chamber  72  which has an inlet with an inlet valve  73 , and an outlet with an outlet valve  74 . A side wall of the pump chamber  72  can be configured as a flexible or mobile diaphragm  76  which can be moved from outside of the pump chamber  72  by means of an actuator (not shown). The actuator can act mechanically, pneumatically or hydraulically on the diaphragm  76 . 
         [0071]      FIG. 3 a    shows a first work cycle of the diaphragm pump  70  during which cleaning fluid is drawn into the pump chamber  72 . For this purpose, the diaphragm  76  shown as a continuous line is moved by the actuator along the arrow  77  into the position shown as a dashed line. During the suction or suction cycle, the inlet valve is open to enable an inflow of the cleaning fluid through the inlet depicted by the arrow  78 . At the same time, the outlet valve  74  is closed to prevent a backflow of cleaning fluid through the outlet. 
         [0072]      FIG. 3 b    shows a second work cycle of the diaphragm pump  70  during which cleaning fluid in the pump chamber  72  is discharged under pressure through the outlet. For this purpose, the diaphragm  76  shown as a continuous line is moved by the actuator along the arrow  77  into the position shown as a dashed line. During the discharge or discharge cycle, the outlet valve  74  is open to enable an outflow of the cleaning fluid through the outlet depicted by the arrow  78 . At the same time, the inlet valve  73  is closed to prevent a backflow of cleaning fluid through the inlet. 
         [0073]    If the cleaning fluid is already under pressure at the inlet or pressure is applied upstream from the inlet, this pressure counteracts the backflow against the direction of flow  78  when drawing and discharging. In this case, the inlet valve  73  and/or the outlet valve  74  can be optionally discarded. 
         [0074]      FIG. 4  shows an example of a cleaning and disinfecting device  1  for cleaning endoscopes. The cleaning and disinfecting device  1  comprises a flushing chamber  10  with two flushing levels  12  which can each comprise a wire basket, a perforated plate or a comparable, fluid-permeable resting surface for an endoscope. 
         [0075]    In the flushing chamber  10 , two spray devices  14  are provided for cleaning the outside of endoscopes placed on the flushing levels  12 . The spray devices  14  have suitable feed lines for fluid cleaning and/or disinfecting means which are not shown for reasons of clarity. 
         [0076]    To clean endoscope channels  30  of endoscopes placed on the flushing levels  12 , each flushing level  12  is assigned a connection group  20  that each has a plurality of connections  21  for one endoscope channel  30  in each case. One endoscope channel  30  is connected to a connection  21  in each case and is flushed with cleaning fluid through the connection  21 . 
         [0077]    The depicted number of five connections  21  per connection group  20  is to be understood expressly as an example, more or less than five connections  21  per connection group  20  and/or a different number of connections can be provided for the two connection groups  20 . 
         [0078]    For each connection group  20 , a control device  22  is provided which is supplied with cleaning fluid through a connection line to clean or flush the endoscope channels  30  connected to the connections  21  of the respective connection group  20 . 
         [0079]    The cleaning fluid can originate from a storage tank  28  and passes through a system with a plurality of pumps  24 ,  26  to the two control devices  22 . 
         [0080]    The control fluid is distributed by means of the control devices  22  to the different connections  21  of the respective connection group  20 , wherein individual connections  21  can be configured to to be able to be shut off in the event that only part of the connections  21  of the relevant connection group  20  is needed to clean one or more endoscopes. 
         [0081]    The pump system  24 ,  26  comprises a booster pump  24  configured as a diaphragm pump  70  for each of the supply devices  22 , as well as a common circulating pump  26  configured as a reciprocating pump. 
         [0082]    The circulating pump  26  can be used to pump cleaning fluid through the described line system and any endoscope channels  30  connected to the connections  21 . For this purpose, a sufficiently high, even pressure is applied to the cleaning fluid, such as by means of the circulating pump  26 . 
         [0083]    The booster pumps  24  are connected over the course of cleaning corresponding to the method described above in order to vary or modulate the delivery pressure provided by the circulating pump  26 . The variation or modulation of the pressure level can be separately connected or set for each of the connection groups  20  since each connection group  20  is assigned its own booster pump  24 . 
         [0084]    The cleaning fluid guided through the connections  21  into an endoscope channel flows through the endoscope channel and reaches the flushing chamber  10  at its open end opposite the connection  21 . There, under the influence of gravity, the cleaning fluid flows or drips through the permeable flushing levels  12  into the bottom area of the flushing chamber  10  which can be configured as a reservoir  16 . The cleaning fluid can be drained from the reservoir  16  and discarded, or as shown in  FIG. 4 , can be fed in a closed circuit to the circulating pump  26  to be reused. 
         [0085]    While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims. 
       LIST OF REFERENCE NUMBERS 
       [0000]    
       
           1  Cleaning and disinfecting device 
           10  flushing chamber 
           12  flushing level 
           14  Spray device 
           16  Reservoir 
           20  Connection group 
           21  Connection 
           22  Control device 
           24  Booster pump 
           26  Circulating pump 
           28  Storage tank 
           30  Endoscope channel 
           32  Side wall 
           34  Inner surface 
           40  Contaminant particle 
           42  Biofilm 
           44  Effective contact surface 
           50  Flow profile 
           51  Flow speed 
           52  Distance 
           60  Pressure profile 
           62  Pressure 
           63  Time 
           64  Period 
           70  Diaphragm pump 
           72  Pump chamber 
           73  Inlet valve 
           74  Outlet valve 
           76  Diaphragm 
           77  Membrane movement 
           78  Flow rate 
         A Low-pressure cycle 
         B High-pressure cycle