Patent Publication Number: US-2016235961-A1

Title: Needle-free connector

Description:
TECHNICAL FIELD 
     The present invention relates to a needle-free connector for infusion lines. 
     BACKGROUND ART 
     Needle-free connectors are known, used as valves for the selective insertion of fluids in infusion lines, e.g., of the type comprising venous catheters. This type of connector permits the intravenous administration of drugs or other fluids using needle-free syringes or “sets” circuits terminating in a standard needle-free connector. 
     In detail, the syringes have a connection sleeve which fits into the connector through one of its free ends, moving a sealing element of the connector that seals such end when it is not coupled with syringes. 
     Such sleeve couples in a removable way to the above-mentioned free end, by means of a Luer connection or the like. 
     This way, the intravenous infusion of medical fluids can be obtained, avoiding cases of medical personnel being accidentally pricked or of accidental catheter lacerations. 
     Numerous cases have nevertheless occurred of blood infections related to the use of catheters (or CRBSI), the aetiology of which seems traceable to the use of this type of connector. 
     These infections are most likely tied to the formation of blood clots inside the catheter, due to a backflow of blood from the patient&#39;s vessel to the catheter connected to it, the backflow being caused by a phenomenon known in the technical sector by the name of negative displacement, i.e., the movement of the blood inside the catheter. 
     In fact, during the injection of the fluid from the syringe to the catheter, the above-mentioned sleeve occupies a certain volume inside the connector, where it is placed in fluid-dynamic communication with the catheter and, therefore, with the blood vessel. 
     Following the separation of the syringe from the connector itself, the sleeve leaves a space that tends to be filled by the fluid inside the catheter. 
     Such movement of the fluid from the catheter into the connector produces a backflow, or movement, of the patient&#39;s blood inside the catheter. 
     This blood can cause a clot which, in certain conditions, above all if of large size, can lead to the growth of pathogens and/or occlusions inside the catheter which can seriously jeopardize the patient&#39;s health. 
     Risks for the patient&#39;s health have also been found in the case of positive displacement. 
     A further large drawback of known needle-free connectors is represented by the presence of clearance between the different pieces from which they are made. In fact, such clearance can jeopardize the isolation inside the connector or in any case contribute to those internal pressure variations which produce the above-mentioned negative or positive displacement. 
     DESCRIPTION OF THE INVENTION 
     The main aim of the present invention is to provide a needle-free connector for infusion lines which permits avoiding or strongly restricting the above-mentioned negative or positive displacements. 
     A further object of the invention is to provide a needle-free connector for infusion lines, in which the possibility of any clearance between its component parts is reduced to the utmost. 
     Another object of the present invention is to provide a needle-free connector for infusion lines which can overcome the above mentioned drawbacks of the prior art in the ambit of a simple, rational, easy and effective to use as well as low cost solution. 
     The above mentioned objects are achieved by the present needle-free connector for infusion lines made according to claim  1 . 
     Moreover, the above mentioned objects are achieved by the method for manufacturing a needle-free connector for an infusion line, made according to claim  14 . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages of the present invention will become better evident from the description of a preferred, but not exclusive, embodiment of a needle-free connector for infusion lines, illustrated by way of an indicative, but not limitative example in the accompanying drawings in which: 
         FIG. 1  is an axonometric view of the connector according to the invention; 
         FIG. 2  is an axonometric view of a manufacturing step of the connector according to the invention; 
         FIG. 3  is a longitudinal section view of the connector according to the invention, in one of its manufacturing steps; 
         FIG. 4  is the view of  FIG. 3  in a next step; 
         FIG. 5  is an axonometric view of the connector and of a syringe before their coupling; 
         FIG. 6  is a longitudinal section view of the connector according to the invention which is moved close to the syringe; and 
         FIG. 7  is the view of the previous illustration, wherein the connector is coupled to the syringe. 
     
    
    
     EMBODIMENTS OF THE INVENTION 
     With reference to these figures, globally indicated by 1 is the needle-free connector of the invention. 
     The proposed connector  1  is intended for use with an infusion line, especially of the type comprising an intravenous catheter or of the type made up of or comprising a medical bag or the like. 
     In practice, the connector is an inlet valve for the administration of medical fluids or saline solution, etc. 
     In detail, the connector  1  is of the type adapted to receive the outlet sleeve  2  (or taper) of the needle-free syringe  3  containing the above-mentioned fluid. 
     The proposed connector  1  comprises a containment body  4  which can be coupled, preferably in a releasable way, both to said infusion line and to said syringe  3 . 
     Preferably, this occurs by using locking systems of the Luer lock type or the like. 
     In detail, at its distal end  20 , intended for coupling to the syringe  3 , and at its proximal end  19 , intended for coupling to the catheter, the connector  1  has threaded coupling means that can be of the Luer lock type or the like. 
     Herein below, for more convenient exposition but without loss of general information, reference will be made to the case wherein the infusion line is made up of the above-mentioned catheter, connected at one end to a vessel of a patient while at the other end it is coupled to the connector  1 . 
     In practice, as is known, the patient&#39;s circulatory system remains connected to the catheter, while the syringe  3  is coupled to the connector  1  only when a substance has to be administered. 
     At the end of administration, the syringe  3  is separated from the connector  1 . 
     The containment body  4  of connector  1  is hollow and comprises an entry  7  to its internal volume. 
     The containment body  4  is preferably made of polycarbonate or other plastic material. 
     The body  4  comprises a housing  5 , preferably of tubular shape, intended to be coupled to the syringe  3 , in the way explained above. 
     The housing  5  has a base  6 , at its own proximal end, and an entry  7  at the opposite distal end  11 , i.e. at the free end. 
     The connector  1  of the invention comprises a pipe  8 ,  17  suitable for the fluid-dynamic communication with the catheter, following coupling between this and the connector  1 . 
     In practice, the pipe  8 ,  17  places the inside of the body  4  in communication with the catheter. 
     In turn, the pipe  8 ,  17  comprises a tubular element  8 , substantially needle shaped, having at least an access  9 ,  10  and protruding from the base  6  into the housing  5 , to define between the tubular element  8  and the housing  5  itself a chamber, which is closed at the base  6 . 
     Furthermore, the pipe  8 ,  17  comprises an outlet tang  17 , communicating with the tubular element  8 , suitable for being coupled sealed to the catheter. 
     Preferably, as clearly shown in the illustrations, tang  17  and tubular element  8  are coaxial. 
     In practice, the pipe  8 ,  17  of the invention is separated into two parts by the above base  6  to define the tubular element  8  and the tang  17 . 
     The tubular element  8  therefore protrudes from the base  6  towards the inside of the housing  5 , so that between the external side surface thereof and the internal lateral surface of the housing  5  a chamber is identified which is closed at the base  6 . 
     Preferably, the housing  5  and the pipe  8 ,  17  are axial-symmetric, coaxial and both elongated. 
     In particular, the tubular element  8  is shorter than the housing  5  and its free end  11  does not protrude from the above-mentioned entry  7  and is in fact separate from this and located inside the housing  5 . 
     Always preferably, the tubular element  8  is tapered towards its free end  11 , which can be pointed. 
     Even more in detail, the tubular element  8  can comprise one or more access through holes  9 ,  10  obtained on its side wall, in order to define a fluid-dynamic path  12  which originates from said holes  9 ,  10 , crosses the tubular element  8  and the tang  17  and terminates in the exit  13  of the latter intended, during use, to be located within the catheter. 
     In practice, said fluid-dynamic path is defined by an inner channel  12  obtained axially to the connector  1 , which channel  12  crosses the length of the pipe  8 ,  17 . Preferably, the body  4  of connector  1  is, in its entirety, axial-symmetric. 
     The proposed connector  1  comprises a sealing element  14 , this too preferably axial-symmetric, contained in the housing  5 . 
     The sealing element  14  is suitable for moving between an occlusion position wherein it seals the entry  7  of the housing  5 , preventing the fluid-dynamic communication between the outside of the connector  1  and the aforementioned fluid-dynamic path  12 , and an opening position wherein it frees the entry  7 . 
     In the preferred embodiment of the invention, the sealing element  14  is fitted sealed over the tubular element  8 . 
     In detail, in its occlusion position, the sealing element  14  obstructs the access  9 ,  10  of the tubular element  8 . 
     According to an important aspect of the invention, the connector  1  is constituted by just two members made up of the containment body  4  and of the sealing element  14 , each of which is made in a single body piece. 
     This way, the clearance is eliminated or drastically reduced between the different parts of the invention and the drawbacks of prior art are overcome. Preferably, the housing  5  shapes, at its distal end  11 , an inwardly folded portion  18  so as to define the aforementioned entry  7 . 
     In detail, as said, the housing  5  can be tubular and, in this case, the folded portion  18  has an annular shape to define centrally the above-mentioned entry  7  of the body  4  of the connector  1 . 
     In particular, the housing  5  can be substantially cylindrical. 
     In this case, the entry  7  has smaller dimensions than the inner section of the housing  5  which can also be constant along its entire length. 
     For the purpose of making a connector  1  which is made up of just two pieces but which also comprises such folded portion  18 , the invention envisages a manufacturing method which comprises the steps explained below. 
     First of all, the containment body  4  of the connector  1  is provided, comprising the housing  5  described above and the sealing element  14  (see  FIG. 2 ) is provided. 
     The sealing element  14  is inserted in the housing  5  so the tubular element  8  fits into the sealing element  14  itself, to obtain the reciprocal configurations already explained in the next paragraphs (see  FIG. 3 ). 
     After which, a portion of the housing  5 , comprising the above open and distal end  11 , is heated so as to soften it. 
     Such heating can e.g. be done by means of the use of ultra-sounds. 
     At this point, the heated portion is deformed to define the above folded portion  18  (see  FIG. 4 ). 
     Also note that the method of the invention can also envisage a cold deformation of the above extremal portion of the housing  5 . 
     The sealing element  14  of the invention comprises an occlusion portion  15  which plugs the above-mentioned chamber, to define a pneumatic spring. 
     In practice, the chamber of the housing  5  comprises air and, since it is closed at the base  6 , as explained above, and since it is plugged by the occlusion portion  15  of the sealing element  14 , a closed space, or inter-space  21 , is created in it, which provides resistance to the compression caused by the shift of the sealing element  14 . 
     To be precise, such occlusion portion  15  completely occupies, instant by instant, a section of the chamber, i.e., one of its longitudinal portions. 
     At the time of describing the operation of the invention, it will be explained how such pneumatic spring helps achieve the proposed objects. 
     The sealing element  14  is flexible, and preferably made of a yielding and in particular compressible material, e.g., silicone. 
     In detail, the sealing element  14  is fitted tightly over the tubular element  8  and, preferably, completely covers it when it is in its occlusion position. 
     In the preferred embodiment of the invention, the sealing element comprises a sheath  14  which tightly covers the external surface of the tubular element  8 . 
     In this case, the sealing element  14  can comprise a cavity, preferably blind, suitable for housing at least a distal portion of the tubular element  8  comprising its free end. 
     In practice, the sheath can internally shape a cavity, e.g., with a shape complementary to that of the tubular element  8 , which cavity, when idle, can have smaller dimensions than those of such element. 
     This way, once the sealing element  14  has been fitted over the tubular element  8 , the flexible characteristics of the former hold it firmly onto the latter. 
     In particular, the sheath is coupled with interference to the tubular element  8 . 
     In the preferred embodiment of the invention, the sheath shapes a thickened head  15  comprising the above-mentioned occlusion portion. 
     In this case, the sealing element  14  can also comprise a thinner tail  16  than the head  15 , shaped like a sleeve, which tail  16  extends between the head  15  and the base  6  of the housing  5 . 
     In practice, the head  15  abuts with interference the internal lateral surface of the housing  5 , and therefore of the chamber, and is suitable for sliding along said tubular element  8 , without the continuous adhesion between sheath and tubular element  8  ever failing. 
     In particular, the above mentioned folded portion  18  abuts the head  15 , crushing it, when it is in the above occlusion position. 
     Consequently, the pneumatic spring is also preloaded when it is in “idle” position, which is more precisely the position of maximum extension, which corresponds to the occlusion position of the sealing element  14 . 
     This aspect not only contributes in general to the sealed isolation of the inside of connector  1 , but in detail helps to ensure that the only space subject to change in pressure inside the connector  1  is always and only that placed outside the sheath, i.e., in the inter-space  21  defined around it. 
     The preload helps keep the sheath  14  adhered on the tubular element  8 , because it experiments a pressure from the outside towards the inside which keeps it abutted with the surface of the tubular element  8 . 
     In detail, in the preferred embodiment wherein the access  9 ,  10  or the accesses of the tubular element  8  are placed in distal portion of the tubular element  8 , the head  15  of the sealing element  14  closes and seals, at the same time, such accesses and the entry  7  of the housing  5 , when the sealing element  14  is in occlusion position. 
     In an embodiment not shown, the sheath  14 , at one or more points along the above-mentioned tail  16 , has a number of ribs or grooves to obtain its programmed deformation. 
     Said ribs or grooves can be obtained at the external surface (facing the inter-space  21 ) or the inner surface (i.e., in the above-mentioned inner cavity) of the sheath itself. 
     This solution facilitates both the collapse and the elastic return in the initial configuration of the sheath  14 . 
     Herein below, for convenience of exposure and without loss of general information, reference will be made to the preferred case wherein the tubular element is a pointed needle  8  having a number of above-mentioned side holes arranged at its free distal end. 
     In this case, the head  15  of the sheath  14  makes up a distal end of the sealing element  14  through which the needle  8  or better its pointed distal end  11  can penetrate. 
     Consequently, when the sheath  14  is in the occlusion position, the head  15  surrounds and surmounts the tip of the needle  8 , extending above it until it closes the access  9 ,  10 , while it extends laterally between the needle  8  and the housing  5  to plug the chamber. 
     In detail, the distal portion of the needle  8  which comprises the accesses  9 ,  10  is completely contained in the head  15 , when the sealing element  14  is in the occlusion position and the head  15  is therefore at the distal portion of the housing  5  abutted with its folded portion  18 . 
     When the sealing element  14  moves towards the opening position, according to the procedures shown below, the head  15  moves towards the base  6  of the housing  5 , allowing itself to be perforated by the tip of the needle  8  and surpassing the distal portion of the latter, so as to free the entry  7  of the housing  5  and the accesses of the needle  8 , while however keeping sealed the above-mentioned inter-space  21  which helps define the pneumatic spring. 
     In practice, the elasticity characteristics of the head  15  are such that the needle  8  is able to perforate it through a deformable orifice formed in it, which orifice closes again automatically, sealing itself, when the sealing element  14  returns to the occlusion position and the needle  8  therefore exits from the channel 
     While the head  15  is pierced by the needle  8 , the side walls of the latter are always very adhered onto the orifice, so as to prevent any flow of fluids, including air, through the orifice itself. 
     It must be noticed that the fact that the needle  8  comprises a tip without openings at its top, which tip penetrates the head  15  of the sheath  14  also when this is in the occlusion position, permits avoiding having empty spaces or discontinuities between the needle  8  and the head  15 , wherein air or other fluids could trickle, thus germinating pathogens and in any case potentially compromising the isolation of the fluid-dynamic path  12  from the non-sterilized external environment. 
     In an embodiment of the invention not shown here, the housing  5  comprises, at its base  6 , at least a groove wherein the proximal end of the sheath  14  is interference fitted. 
     In practice, the edge of the proximal end, which preferably identifies a ring around the needle  8 , is fastened within a groove obtained for the purpose in the base  6 , so as to assist the tight adhesion of sheath  14  to the external surface of the needle  8 . 
     The operation of the invention is described below. 
     Initially, the connector  1  is connected to the catheter at its proximal end  19 , while its distal end  20  which comprises the entry  7  is free. 
     The entry  7  is closed by the sealing element  14  which, in this step, is in the occlusion position, where it isolates and seals the above fluid-dynamic path  12 . Every time the medical staff members have to administer a substance, they couple the syringe  3  to the housing  5  causing its dispensing sleeve  2  to penetrate through the entry  7 . 
     This way, the sleeve  2 , or taper, of the syringe  3  presses against the head  15  of the sealing element  14 , moving it along the needle  8  in the direction of the several times mentioned base  6  (see  FIG. 7 ). 
     In this step, the distal portion of the needle  8  is uncovered, and the sleeve  2  of the syringe  3  receives it internally. 
     When the sealing element  14  reaches the opening position, the sleeve  2  of the syringe  3  also internally comprises the accesses  9 ,  10  of the needle  8 . 
     The dimensions and the shape of needle  8  and sleeve  2  are selected in such a way that the former fits sealed into the latter. 
     In this step, the pneumatic spring is loaded, by effect of both the compression of the air contained in the above inter-space  21 , and of the elasticity of the sealing element itself. 
     In sliding along the needle  8 , the sheath  14  always remains substantially strongly adhered to it, including thanks to the increase in pressure inside the inter-space  21  which compresses the sheath  14  against the external surface of the needle  8 . 
     This way, no empty space is created between sealing element  14  and needle  8  or between needle  8  and sleeve  2 . 
     In this step, the fluid-dynamic path  12  defined within the connector  1  places the inside of the syringe  3  in communication with the catheter. 
     Consequently, the health worker injects the envisaged dose of fluid from the syringe  3  to the catheter passing through the connector  1 . 
     At this point, the operator extracts the sleeve  2  from the housing  5  of the connector  1 . 
     Advantageously, the sealing element  14  climbs back up along the needle  8 , as the sleeve  2  is gradually removed from the latter, without delay and without therefore allowing an empty space to form between sleeve  2 , needle  8  and sealing element  14 , especially at the distal portion of the needle  8 . 
     This way, when the sleeve  2  passes by the accesses, the fluid included in the fluid-dynamic path  12  does not undergo any appreciable aspiration in the direction of the accesses of the needle  8  and, consequently, no negative displacement is produced of the blood within the catheter, except to a negligible extent. 
     What is more, the invention completely prevents the occurrence of positive displacements.