Abstract:
A coupling arrangement for a system for endotracheal ventilation of a patient is disclosed. The system includes an endotracheal tube and a manifold configured for allowing ventilation of the patient via the endotracheal tube, which manifold has a first coupling element with an axial extent and with engagement element; and which endotracheal tube has a second coupling element with an axial extent and with engagement element; wherein the coupling arrangement is configured to produce, when the first and the second coupling elements are moved together in the axial direction, a locking engagement between the engagement elements.

Description:
The present invention relates to a coupling arrangement of the kind described in the preamble to claims 1 and 2. The coupling arrangement can be used for connecting a manifold of the kind described in eg WO98/33536 and U.S. Pat. No. 5,487,381 to an endotracheal tube. 
     BACKGROUND OF THE INVENTION 
     It is commonly known to configure the end of an endotracheal tube with a conically tapering male coupling means that is introduced into a complementarily configured female coupling means on the manifold for establishing a sealing frictional connection. In order to separate the parts from each other it is necessary to produce an axial separation force. This force is typically produced by means of a disengagement means in the form of a wedge-shaped manifold or fork that is wedged between two protruding flanges located at the end of the female and the male coupling means, respectively. 
     However, it has been found that by use of said manifold in practice, it is difficult for the hospital staff to avoid laterally oriented power influences on the coupling means and thus on the endotracheal tube that has been inserted into the patient with ensuing traumatic consequences for the patient. Besides, the prior art solutions involve a risk that the manifold disappears. In given situations, the latter has entailed that the hospital staff have attempted to separate the coupling means manually, which has, to an even wider extent, traumatically influenced the patient due to laterally oriented power influences. 
     BRIEF SUMMARY OF THE INVENTION 
     It is the object of the invention to solve the above-mentioned problems by the prior art. As featured in the characterising portions of claims 1 and 2 this is obtained by arranging a thread for a disengagement means on either the manifold or in connection with the endotracheal tube. By the solution thus provided it is ensured that, at any time, the separation force is oriented essentially in the axial direction, and that no power influences occur transversally to the coupling means. Additionally, it becomes possible to avoid that the disengagement means is lost. 
     It is also preferred that the coupling means are configured as male and female parts, respectively, as featured in claims 3 and 4. Preferably the coupling means are configured with engagement means in the form of complementary conical faces whereby it is possible to provide a frictional coupling in conventional manner as such. However, nothing prevents the engagement means from being configured in another manner, eg so as to provide a releasable joining by clipping together the engagement parts while profiting from the resilience of the constituent materials. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention will now be described in further detail with reference to the embodiments shown in the drawing. In the drawing: 
         FIG. 1  illustrates a part of a system for endotracheal ventilation of a patient; 
         FIG. 2  illustrates a manifold in a perspective view and featuring a part of the coupling arrangement according to the invention; and 
         FIG. 3  is a cross sectional view through the coupling arrangement according to the invention, without the disengagement means. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In principle, the functionality of the system shown in  FIG. 1  corresponds to the functionality of eg the system described in DK patent application No 32/95. The system shown is thus suitable for performing ventilation as well as aspiration of a patient and is thus conventionally designated a ‘closed’ system. A flexible shrouding or pipe coupling  50  is thus, at its first end  52 , connected to the valve device  200  and it is, at its opposite end  54 , connected to a manifold  100 . The valve housing  200  is configured for being, via a coupling  5 , connected to a not shown suction device for generating a sub-atmospheric pressure in the system. 
     The manifold  100 , which is preferably transparent, is also configured to be connected—via a coupling arrangement—to a tubular element or “tube” for endotracheal ventilation of a patient, ie a tube configured for being introduced into the respiratory tracts of the patient with a view to maintaining artificial ventilation of the patient. To this end, the manifold  100  has a coupling device, designated in the drawing by the reference numeral  300  and to be described in further detail below. An opening  142  in a ventilation stub  141  allows ventilation of the patient by means of a not shown conventional apparatus. To this end the ventilation stub  141  is preferably configured with a screw thread for connection with the ventilation apparatus. 
     Besides, the system conventionally comprises a catheter  40  that extends within the interior of the shrouding  50  and that can be introduced into the patient&#39;s respiratory tracts to draw out secretion. At its first end  42 , the catheter  40  is securely connected to the valve device  200  and, at its opposite end  44 , it is displaceably received in the manifold  100 , the catheter being—via a packing  104 —sealed relative to the shrouding  50  so as to prevent fluid from penetrating into the shrouding. Also, the packing  104  causes secretion to be scraped off the outside of the catheter  40  during withdrawal of the catheter from the patient. It will be understood that the opposite end  44  of the catheter forms a suction point that can, while the shrouding  50  is simultaneously folded, be displaced through the manifold interior and into the not shown tube for ventilation of the patient. By this movement, the end  44  of the catheter is thus conveyed to the right in  FIG. 1 . Hereby it is possible to perform regular suction of secretion from the patient&#39;s respiratory tracts, as the operator connects the system to the suction device by operating an actuator button  210  arranged in the valve housing  200 . 
     As mentioned above, the manifold  100  has a coupling device that constitutes a first coupling means  300  of a coupling arrangement  300 ,  330 ,  400 . This first coupling means is shown more clearly in  FIG. 2 , from where it will also appear that the manifold  100  defines a through-going axis A. In the embodiment shown the coupling means  300  is constituted by a separate pipe coupling that is configured for being able to be fastened in extension of the manifold  100  via an engagement area  150  on the outside of the manifold  100  and that extends along the axis A. However, the coupling means  300  may very well be formed integrally with the manifold  100 . The coupling means  300  has an interiorly extending, through-going passage for ventilation and aspiration of the patient, and it has at its one end a first cylindrical area  310  that continues—via an annular plateau  312  that extends perpendicular to the axis A—into a cylindrical area  315  provided with an exterior thread  320 . 
     In  FIG. 3 , the coupling arrangement is shown in further detail. To the left in the drawing the coupling means  300  thus shown that has, to the extreme right, an annular end edge  317 . The passage in the cylindrical area  315  has, as will appear, an evenly increasing interior diameter in a direction away from the manifold  100 , whereby it is possible to provide a frictional joint between the first coupling means  300  and a second coupling means  400 , which is shown to the right in  FIG. 3 , and comprising an area  420  that is complementary with the area  315 . 
     The second coupling means  400  is, as shown, configured as a cylindrical body with a through-going passage that extends along the axis A like the passage in the first coupling means  300 . A tapering area  420  of the second coupling means  400  has an increasing, exterior diameter that has been adjusted in accordance with the change in the interior diameter of the passage within the area  315  in the first coupling means  300 . Thereby it is possible to provide a sealing frictional coupling by introduction of the second coupling means  400  into the first coupling means  300 . When the manifold  100  is to be connected to an endotracheal tube, said joining of the two coupling means is performed for establishing a very sealing frictional connection. The tapering of the passage within the area  315  and the area  420  can be comprised within the preferred ratio of about 1 to 40. 
     The second coupling means  400  also comprises a plateau  430  that extends perpendicular to the axis A, which plateau forms a transition between the tapering area  420  and a head portion  410  of the coupling means  400 . The head portion  410  can either be solidly connected to the end of an endotracheal tube, or it can be configured for being solidly connected to the end of an endotracheal tube immediately preceding the introduction into the patient of the endotracheal tube. It will be understood that the first coupling means  300  will, in the relevant case, form a female coupling means, whereas the second coupling means  400  forms a male coupling means. 
     Additionally the coupling arrangement comprises the disengagement means  350  shown in  FIG. 2  that has an internal thread  360  configured for cooperating with the thread  320 . The plateau  312  forms a first end position for the disengagement means  350 , since preferably the extent of the disengagement means  350  along the axis A corresponds maximally to the extent of the thread  320  along the axis A. 
     When the second coupling means  400  has been introduced into the coupling means  300 , the end edge  317  is preferably in abutment on the plateau  430 . In this state, there will preferably be a certain distance between the plateau  430  and the disengagement means  350  that has been screwed onto the area  315 . In order to be able, in this state, to perform a separation of the two coupling means, the disengagement means  350  is turned a suitable number of times, whereby the means  350  is displaced and caused to abut on the plateau  430 . By carrying out a further manual turning of the disengagement means  350 , an axial power influence is generated towards the second coupling means  400 . The power influence is oriented in accordance with the axis A and will entail that the second coupling means  400  is released. The pitch of the threads  320 ,  360  can be selected in accordance with the forces involved, including the ease with which the user must be able to turn the disengagement means  350  in order to achieve the intended separation.