Abstract:
An apparatus for providing access to a target site in a living body, comprises a first elongated member including a proximal opening to a first lumen and a branching point at a distal end thereof and a second lumen open to the first lumen at the branching point, the second lumen extending to a second lumen distal opening at a first connector, the first connector configured to engage a proximal end of a first lumen of a multi-lumen catheter in combination with a third lumen open to the first lumen at the branching point, the third lumen extending to a third lumen distal opening at a second connector, the second connector configured to engage a proximal end of a second lumen of a multi-lumen catheter.

Description:
BACKGROUND 
       [0001]    Catheters are generally used for the introduction of fluids to and/or the withdrawal of fluids from living bodies. Venous Access Devices (“VAD”s) such as peripherally inserted central catheters (“PICC”s) are formed as elongated flexible tubes used to deliver fluids, nutrients, etc. over an extended period of time or to aspirate blood from the patient for diagnosis. Presently available VADs are formed with single or multiple lumens to deliver, for example, different agents to different target sites in a living body or to provide simultaneous infusion and withdrawal, as those skilled in the art will understand. Each of these lumens may be connected to a separate infusion or withdrawal source to affect flow therethrough. 
       SUMMARY OF THE INVENTION 
       [0002]    In one aspect, the present invention is directed to apparatuses for providing access to a living body, comprising a first elongated member including a proximal opening to a first lumen and a branching point at a distal end thereof and a second lumen open to the first lumen at the branching point, the second lumen extending to a second lumen distal opening at a first connector, the first connector configured to engage a proximal end of a first lumen of a multilumen catheter in combination with a third lumen open to the first lumen at the branching point, the third lumen extending to a third lumen distal opening at a second connector, the second connector configured to engage a proximal end of a second lumen of a multi-lumen catheter. In another aspect, the present invention is directed to a flow control element within a multi-lumen catheter, which flow control element provides separate fluid flow paths for the multiple lumens of a catheter during low pressure or low-flow conditions, but which selectively places the multiple lumens of the catheter in fluid communication with one-another during high pressure or high-flow conditions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  shows a perspective view of a first exemplary device according to an embodiment of the invention. 
           [0004]      FIG. 2  is a schematic view of flow balancing element of a device in accordance with one aspect of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0005]    The present invention may be further understood with reference to the following description and the related appended drawings. The present invention describes a device for use with a multi-lumen catheter for infusion of agents into a target structure in a living body (e.g., a blood vessel, body cavity, etc.) and/or the removal of fluids or other materials therefrom. The flow device of the present invention facilitates the flow of high pressure fluids from a single fluid source into both lumens of a dual-lumen catheter, making possible the use of higher flow rates than available through either lumen of the catheter. Although exemplary embodiments of the present invention are described with respect to dual-lumen catheters and dual-lumen flow devices, the system  100  may be formed with any additional number of lumens without deviating from the spirit and scope of the present invention. 
         [0006]      FIG. 1  depicts the system  100  according to the present invention comprising a flow device  102  connected to a dual-lumen catheter  104 , a distal end (not shown) of which is open to a target anatomical structure when implanted in an operative configuration. A port  106  at a proximal end of the flow device  102  is configured in a conventional manner to engage a single injection source (not shown). Alternatively, the port  106  is attached to a device for withdrawing fluid from the body. The port  106  is connected to a single lumen  108  tube which extends distally to an adaptor  110  which separates flow from the lumen  108  into the lumens  112 ′,  114 ′ of two separate tubes  112 ,  114 , respectively. The adaptor  110  may be of any suitable shape to achieve the desired flow separation including, without limitation, Y-shaped, H-shaped, or in the form of a manifold. In alternate embodiments, the adaptor  110  may further comprise a stopcock  130  or a pressure activated valve (not shown) to control the flow of fluid through one or more of the lumens  112 ′,  114 ′. The adaptor  110  provides a connection between the single lumen  108  and each of lumens  112 ′,  114 ′. The lumens  112 ′,  114 ′ are preferably formed with the same dimensions but, alternatively, can be formed with different dimensions and/or features to affect flow therethrough. 
         [0007]    A distal end of each of the tubes  112 ,  114  includes a luer port  116  configured to engage a respective luer port of a dual-lumen catheter  104 . Specifically, the luer ports  116  may be formed, for example, as male luer ports with collars  118  that can be rotated to lock against female luer ports  120  of tubes  122 ,  124  of the dual-lumen catheter  104 , as those skilled in the art will understand. Furthermore, each of the tubes  112 ,  114  is preferably formed of a flexible material and of a length permitting a degree of movement sufficient to facilitate connection of the flow device  102  and the dual-lumen catheter  104 . As would be understood by those skilled in the art, the dual-lumen catheter  104  may include pinch valves  134  or other means for sealing the lumens when the catheter  104  is not in use. Distal ends of each of the tubes  122 ,  124  are fluidly connected to a connector  126  which draws each of the tubes  122 ,  124  into a single, dual lumen, outer tube  128  insertable into the body in the operative configuration, as is known to those of skill in the art. 
         [0008]    In an alternate embodiment of the present invention, the system  100  may comprise a fluid management manifold (not shown) formed with a predetermined number of male luer ports that are attachable to female luer ports of a multi-lumen catheter. The fluid management manifold may facilitate the attachment of the multi-lumen flow device  102  of the present invention to a multi-lumen catheter irrespective of the number of lumens each element comprises. 
         [0009]    In still another embodiment, each of the lumens  112 ′,  114 ′ may further comprise a valve  132  located, for example, in the luer port  116  and configured to prevent any back-flow of fluid from the catheter  104 , as those skilled in the art will understand. For example, one or more of the valves  132  may be constructed to remain closed to prevent flow therethrough at all times during which a predetermined parameter is not met or exceeded (e.g., flow rate, velocity, pressure, etc.). For example, the valves  132  may be pressure activated so that, when a fluid pressure within the one of the lumens  112 ′,  114 ′ corresponding to the particular valve  132  is less than a predetermined magnitude, the valve  132  remains closed sealing the corresponding lumen  112 ′,  114 ′. When the fluid pressure within this one of the lumens  112 ′,  114 ′ exceeds the predetermined magnitude, the valve  132  opens to permit fluid flow therethrough. Those skilled in the art will understand that, depending on the characteristics of the individual lumens of the catheter  104  and any valves therein, different threshold pressures may be set for the valves  132  in the corresponding lumens  112 ′,  114 ′ to which these lumens will be connected. For example, where the pressure in the lumen  108  and the setting of any flow balancing/biasing features is such that the pressure in the lumen  112 ′ is greater than the threshold for the corresponding valve  132  while the pressure in the lumen  114 ′ is lower than the threshold for its valve  132 , fluid will flow only through the lumen  112 ′ and the corresponding lumen of the catheter  104  while no fluid flows through the lumen  114 ′ and the corresponding lumen of the catheter  104 . If the pressure within the lumen  108  rises to the point at which the pressure in the lumen  114 ′ exceeds its threshold level, its valve  132  opens to permit flow therepast. Thus, the valves  132  may be configured to permit the use of one lumen of a multi-lumen catheter when flow through the flow device  102  meets a first predetermined condition and permits the use of more than one lumen when the flow meets a second predetermined condition. The valves  132  thus act as a safety precaution to prevent overpressurization within the catheter  104 , as those skilled in the art will understand. 
         [0010]    In another embodiment of the present invention, one or more of the pressure-activated valves  132  may be replaced by a transducer/valve combination (not shown) that function in a manner substantially similar to the valves  132  described above. Specifically, the transducers may be configured to monitor one or more parameters within the lumens  112 ′,  114 ′ as described above and provide a signal to a control system (not shown) that opens a valve in the corresponding lumen when the parameter in that lumen meets the predetermined conditions. It is noted that the aforementioned embodiments are exemplary only and that the valves  132  of the device  100  may be configured to permit flow at any predetermined rates and parameters without deviating from the scope of the present invention. 
         [0011]    In another embodiment, at least one of the lumens  112 ′,  114 ′ may be provided with an overpressure safety mechanism such as a rupture disk (not shown) that prevents overpressurization of the catheter  104 , as those skilled in the art will understand. Specifically, if a pressure within one or both of the lumens  112 ′,  114 ′ exceeds a predetermined threshold, the rupture disk bursts externally of the body, preventing damage to the catheter  104  and any leakage within the body of the fluids being transferred. 
         [0012]    In another aspect of the present invention, a flow-balancing feature is provided within a multi-lumen catheter to facilitate power injection. In the exemplary embodiment depicted in  FIG. 2 , the flow balancing feature comprises an H-shaped connector  180  with two lumens,  190 ,  191 , which lumens are in fluid communication with two lumens of a catheter. The lumens  190 ,  191  of the H-shaped adaptor  180  share a common wall  185 , which wall includes a flow control element  186 . In the embodiment shown in  FIG. 2   a , the flow control element includes a spring  187  and a surface which is acted upon by pressures in lumens  190 ,  191 . As shown in  FIG. 2   d , when the fluid pressures in lumens  190  and  191  are below a threshold level, the flow control element is not activated, and the common wall remains in place between the lumens  190 ,  191 . However, when the pressures in either of lumens  190  or  191  exceeds a pre-determined threshold level, as shown in  FIG. 2   e , the flow control element  186  is activated, the wall  185  between lumens  190 ,  191  is breached, and the lumens  190 ,  191  are placed into fluid communication with one another. 
         [0013]    In another aspect, the present invention includes a method of using a flow-control element to perform power injections using a catheter. In certain embodiments, users can optionally utilize a single luer input of a multi-lumen catheter to perform power injections. As discussed above, and as shown in  FIG. 2   e , when the pressure in the fluid flow path being utilized for power injection exceeds a threshold pressure, the flow control element  186  is activated, and the fluid being power injected will flow into the second fluid flow path. To prevent reflux towards the proximal luer of the catheter, a check-valve or clamp can be utilized. 
         [0014]    It is noted that the embodiments shown are shown for illustrative and descriptive purposes only and are not intended to describe the bounds of the present invention which is to be limited only by the scope of the claims appended hereto. There are many modifications of the present invention which will be apparent to those skilled in the art without departing from the teaching of the present invention. Various modifications may be made to the size and shape of the flow device without deviating from the spirit and scope of the present invention.