Abstract:
A drain catheter comprises a proximal drain tube having a proximal end adapted to outlet drained liquids and a distal end. A tube interface is at a distal end of the proximal drain tube, the tube interface having at least two canals open to a distal end of the proximal drain tube, the at least two canals being in fluid communication with the proximal drain tube. Two or more distal drain tubes each having a proximal end and a distal end, the proximal end of each said distal drain tube being connected to a corresponding one of the canals such that the distal drain tubes are each in fluid communication with the corresponding one of the canals, the distal end of each said distal drain tube being open to collect liquids, a lumen of the distal drain tubes being smaller than a lumen of the proximal drain tube.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present invention claims priority on U.S. Provisional Application Ser. No. 61/659,504, filed on Jun. 14, 2012, and incorporated herewith by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to drain catheters for draining fluids from a body cavity, such as various cavities within the mediastinum. 
     BACKGROUND OF THE INVENTION 
     Drain catheters are commonly used for the drainage of bodily cavity. For instance, cavities in the mediastinum may require drainage subsequent to surgery, to avoid complications such as pericardial effusion. It is known to bundle a few small drain catheters and insert them concurrently through a blood vessel, whereby the drain catheter inlets of the bundle are spread out in the cavity that must be drained. However, the performance of some prior art drains may be affected by bodily debris (e.g., clots, etc). Indeed, the size of catheters is limited by blood vessel dimensions, and drain catheters of smaller diameter may become clogged. Moreover, the frictional forces in drain catheters of smaller diameter are also relatively high compared to drain catheters with a greater lumenal area. 
     SUMMARY 
     It is therefore an aim of the present disclosure to provide a drain catheter that addresses issues related to the prior art. 
     Therefore, in accordance with a first embodiment, there is provided a drain catheter comprising: a proximal drain tube having a proximal end adapted to outlet drained liquids and a distal end; a tube interface at a distal end of the proximal drain tube, the tube interface having at least two canals open to a distal end of the proximal drain tube, the at least two canals being in fluid communication with the proximal drain tube; and at least two distal drain tubes each having a proximal end and a distal end, the proximal end of each said distal drain tube being connected to a corresponding one of the canals such that the distal drain tubes are each in fluid communication with the corresponding one of the canals, the distal end of each said distal drain tube being open to collect liquids, a lumen of the distal drain tubes being smaller than a lumen of the proximal drain tube. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an assembly view of a drain catheter in accordance with an embodiment of the present disclosure; 
         FIG. 2  is an assembly view of the drain catheter of  FIG. 1 , featuring interface body portions; 
         FIG. 3  is an assembly view of the drain catheter of  FIG. 1 , with longitudinal slits in a tube interface; 
         FIG. 4  is a longitudinal view of drain catheter in accordance with an embodiment of the present disclosure; 
         FIGS. 5A to 5E  are cross-sectional views of the drain catheter of  FIG. 4 , taken at various locations along the drain catheter; and 
         FIG. 6  is a reference sectional view of the drain catheters of  FIGS. 1 and 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring to the drawings and more particularly to  FIG. 1 , a drain catheter in accordance with the present disclosure is generally shown at  10 . The drain catheter  10  is used for the drainage of bodily fluids from body cavities. For instance, the drain catheter  10  may be used for the drainage of fluid from cavities within the mediastinum, for instance after cardiac surgery. Hence, the drain catheter  10  has a proximal end located outside the body, and a distal end within the body, with the longitudinal body of the drain catheter  10  within a body vessel. 
     The drain catheter  10  has a main proximal drain tube  11 , a tube interface  12  and two or more distal drain tubes  13 . For clarity purposes, the main proximal drain tube  11  is relatively short in  FIG. 1  (e.g., fragmented), but may have a substantial length relative to its outer diameter, to extend out of the body. Moreover, the length of the main proximal drain tube  11  may be substantially greater than the length of each distal drain tube  13 . The tube interface  12  may be in or out of the body while the distal drain tubes  13  are mostly, if not fully, within the body. The end of the main proximal drain tube  11  located outside the body at end P is configured to be connected to any suitable suction source, fluid collection system, drainage device or accessory, while the free ends of the distal drain tubes  13  at end D of the drain catheter  10  are distributed at various locations of a body cavity to drain. Various types of connectors may be located at the proximal end P of the main proximal drain tube  11 . Any appropriate medical grade material may be used for the main proximal drain tube  11 . For instance, a silicone such as Silastic® of Rx type may be used, with the hardness being selected as a function of the contemplated use, to sustain suction pressures in the range of 20 cm H 2 O without collapsing. 
     The tube interface  12  is inserted into a distal-most end of the main proximal drain tube  11 . The tube interface  12  is the interface between the main proximal drain tube  11  and the plurality of distal drain tubes  13 . The tube interface  12  is connected to the main proximal drain tube  11 . The tube interface  12  may be sealingly connected to the main proximal drain tube  11 , so as to minimize pressure lost at the junction between the tube interface  12  and the main proximal drain tube  11 . The tube interface  12  is described in further details hereinafter. 
     Still referring to  FIG. 1 , there is illustrated three of the distal drain tubes  13 . The drain catheter  10  has two or more of the distal drain tubes  13 . The amount of distal drain tubes  13  is limited by the minimal dimensions of the distal drain tubes  13 : i.e., depending on the application, a minimal diameter is required for the distal drain tubes  13  to operate efficiently. According to an embodiment, each of the distal drain tubes  13  is a multi-lumen catheter tube having longitudinal channels  13 A extending the full length of the distal drain tube  13  to maximize the amount of fluid captured by the drain tubes  13 , with a central cross-shaped core  13 B extending along the distal drain tubes  13  to provide structural integrity to the distal drain tubes  13 , and to support the elongated peripheral wall portions  13 C forming the outer periphery of the distal drain tubes  13 . The assembly of the central cross-shaped core  13 B and the elongated peripheral wall portions  13 C defines conduits within the drain tube  13 . For instance, the distal drain tubes  13  may be similar to the flexible drain portion described in U.S. Pat. No. 4,398,910, granted to Blake et al. on Aug. 16, 1983. Other distal drain tube configurations are considered as well, with more or fewer of the longitudinal channels  13 A. For instance, perforated tubes and like other tubes may be used. To minimize any pain sustained by the patient, the distal drain tubes  13  are made of a flexible and resilient material, such as silicone. 
     Referring to  FIG. 1 , the tube interface  12  is shown having a cylindrical body  20  shaped to fill the interstitial space between the inner diameter of the proximal drain tube  11  and the outer diameters of the distal drain tubes  13 , in a generally airtight arrangement. Referring to  FIG. 2 , the cylindrical body  20  may consist of a plurality of cylindrical body portions  20 A,  20 B and  20 C. The number of body portions is generally equivalent to the number of distal drain tubes  13 . For instance, if the drain catheter  10  has two distal drain tubes  13 , the tube interface  12  has two cylindrical body portions concurrently forming the cylindrical body  20 . 
     An outer diameter  21  of the cylindrical body  20  is sized so as to be received in the distal-most end of the main proximal drain tube  11 . Any appropriate type of interconnection between the tube interface  12  and the main proximal drain tube  11  is considered, such as a deformation fit, with or without the use of adhesives, etc. Referring to  FIGS. 1 and 2 , the cylindrical body  20  has canals  22  that will each receive a distal drain tube  13 . Accordingly, the cylindrical body  20  has the same number of canals  22  as of distal drain tubes  13 . In another embodiment, the canals  22  converge to a single canal at a proximal end of the tube interface  12 . An inner diameter  23  (i.e., lumen) of each of the canals  22  is sized to accommodate a proximal-most end of the distal drain tubes  13 , with the distal drain tubes  13  extend freely beyond the tube interface  12 . The assembly of the distal drain tubes  13  to the tube interface  12 , and of the tube interface  12  to the main proximal drain tube  11  is strong enough that these components remain connected to each other when the drain catheter  10  is pulled out of the body, despite frictional forces of the drain catheter with surrounding bodily tissue. 
     The cylindrical body  20  is made of a medical grade material. According to an embodiment, the cylindrical body  20  is made from silicone, with a non-negligible level of resiliency. One type of silicone that may be used is Silastic® of Rx type. In an embodiment, it is considered to use the same material for the distal drain tube  13 , although differing materials may be used as well. According to an embodiment, the cylindrical body  20  has a greater rigidity than the distal drain tubes  13 . 
     With reference to  FIG. 2 , the cylindrical body portions  20 A,  20 B and  20 C are assembled onto the proximal-most ends of the distal drain tubes  13 . This ensures that the peripheral material of the canals  22  properly covers the ends of the distal drain tubes  13  and therefore produces a generally fluid-tight joint. In assembling the distal drain tubes  13  to the tube interface  12 , the length of the distal drain tubes  13  is adjusted by the user. The assembly of the cylindrical body portions  20 A,  20 B and  20 C capturing the ends of the distal drain tubes  13  may then be inserted in the main proximal drain tube  11 , using any appropriate type of manufacturing. For instance, the main proximal drain tube  11  may be resiliently deformed to insert the assembly therein. 
     Referring to  FIG. 3 , an alternative embodiment of the tube interface  12  is shown, with the cylindrical body  20  having slits  25  in communication with each of the canals  22 . In an embodiment, the slits  25  extend the full length of the canals  22 . In the natural state of the cylindrical body  20 , the slits  25  are closed by the resilience of the material of the cylindrical body  20 . The slits  25  may however be manually opened for the insertion therein of the distal drain tubes  13 . Once the distal drain tubes  13  are inserted in the tube interface  12  (with an appropriate length of the tubes  13  extending beyond the interface  12 ), the assembly may be inserted in the distal-most end of the main proximal drain tube  11 . 
     It is observed that total frictional forces per volume of fluid are relatively lower for fluids circulating in the main proximal drain tube  11  with its single lumen, over the frictional forces for fluids in the plurality of distal drain tubes  13 . Hence, the drain catheter  10  benefits from the lower frictional forces of the main proximal drain tube  11  for a substantial portion of the overall length of the drain catheter  10 . Therefore, instead of having a plurality of tubes extending from an exterior of the body to the drained cavity, the use of a single proximal drain tube of greater lumenal dimensions connected to a plurality of distal drain tubes of smaller lumenal dimensions enhances the drainage of fluid. Moreover, by using distal drain tubes  13  having longitudinal grooves  13 A extending proximally to the tube interface  12  and to the main proximal tube  11 , as in  FIG. 1 , the distal drain tubes  13  expose substantial drainage area to drain fluids from the bodily cavities. This may reduce the risk of clogging the various tubes. 
     It is observed that the drain catheter  10  has a circular cross-sectional area. However, the drain catheter  10  may have any appropriate cross-sectional shapes (oval, etc), depending on the use of the drain catheter  10 . 
     Referring to  FIGS. 4 and 5A-5E , the drain catheter is shown at  10 ′ in accordance with another embodiment of the present disclosure. The drain catheter  10 ′ is similar to the drain catheter  10  shown in  FIGS. 1-3 , whereby like elements will bear like reference numerals. One difference between the drain catheters  10  and  10 ′ is the interface portion  12 ′ of the catheter  10 ′ between the main proximal tube  11  and the distal drain tubes  13 . 
     More specifically, referring concurrently to  FIGS. 4 and 5E , it is observed that the drain catheter  10 ′ has the main proximal tube  11  with a circular cross-section (although other section shapes are considered). The circular cross-section is well suited for the connected of the main proximal tube  11  to a suction source. The distal drain tubes  13  have the longitudinal channels  13 A, the central cross-shaped cores  13 B, and the resulting conduits extending along the drain tubes  13 . 
     The drain catheter  10 ′ is a single integral molded piece that may have an edgeless outer surface, with the interface portion  12 ′ being the transition between the circular shape of the main proximal tube to the specific shape of the distal drain tubes  13  as shown in  FIG. 5E . Hence, as shown in  FIG. 5A , the interface portion  12 ′ has three lobes  40 . The number of lobes is in accordance with the number of distal drain tubes  13 . As shown in  FIG. 5B , the interface portion  12 ′ transitions from the three-lobe configuration of  FIG. 5A , to a configuration of three conduits  41  of circular inner diameter. As shown in  FIG. 5C , the three interconnected conduits  41  of  FIG. 5B  detach to form three individual tubes  42 , having a diameter generally corresponding to that of the distal drain tubes  13 . Then, sequentially to  FIG. 5D , the tubes  42  of  FIG. 5C  feature the central cross-shaped core  13 B, but without the longitudinal channels  13 A, to then reach the configuration of  FIG. 5E . 
     In  FIGS. 5A to 5E , dimensions are provided as an example. These dimensions can be increased or reduced, proportionally to the outer diameter of the main proximal drain tube  11  of drain tubes  13 . Referring to  FIG. 6 , various embodiments are provided with dimensions. These dimensions are provided as an example, and the drain catheters  10 / 10 ′ should not be restricted to these dimensions, as other dimensions are also considered. 
     In accordance with a first embodiment, the drain tube  11  has an inner diameter 2 R of about 20 mm, with a thickness d of about 2 mm, for an outer diameter of about 24 mm. The nominal length of the drain tube  11  is up to 1 m. Still in the first embodiment, the outer diameter of the tube interface  12 / 12 ′ is of about 20 mm (i.e., 2 R), while the canals  22  have a radius r of about 4 mm. The distance B between the canals  22  is about 2.4 mm. The length of the tube interface  12 / 12 ′ is about 40 mm. Still in the first embodiment, the outer diameter of the distal tubes  13  is of about 8 mm (i.e., 2 r). The length of the distal tubes  13  is about 700 mm. 
     The inner diameter of the drain tube  11  may range between 10.0 mm and 25.4 mm. The other dimensions of the drain catheter  10 / 10 ′ are generally proportional to that of the inner diameter of the drain tube  11 . In accordance with a second embodiment, the drain tube  11  has an inner diameter 2 R of about 10 mm, with a thickness d of about 2 mm, for an outer diameter of about 14 mm. The nominal length of the drain tube  11  is up to 1 m. Still in the second embodiment, the outer diameter of the tube interface  12 / 12 ′ is of about 10 mm (i.e., 2 R), while the canals  22  have a radius r of about 1.66 mm. The distance B between the canals  22  is about 2.44 mm. The length of the tube interface  12 / 12 ′ is about 40 mm. Still in the second embodiment, the outer diameter of the distal tubes  13  is of about 3.3 mm (i.e., 2 r). The length of the distal tubes  13  is about 700 mm. In an embodiment, the outer diameter of the proximal drain tube  11  is greater than a sum of an outer diameter of two of the distal drain tubes  13 . 
     It is observed that the tube interface  12 / 12 ′ is arranged such that there is no increase in diameter from the distal tubes  13  to the main drain tube  11 , the largest outer diameter being that of the main drain tube  11 . Whether the main drain tube  11  actually enters the body or not, the arrangement of the figures allows to use a single suction port and a single tube ( 11 ), for two or more distal drains  13  located at different regions of a body cavity. This may result in increased coverage resulting in enhanced drainage.