Abstract:
A drainage or infusion catheter comprises a flexible tube that terminates at the distal portion thereof in an apertured spiroid. The flexible tube has one or more subcutaneous cuffs, affixed at the midportion of the tube, and one or more pairs of opposed offsets of the tube between the proximal end and the distal portion thereof.

Description:
FIELD OF INVENTION 
     This invention relates generally to catheters suitable for the exchange of fluid, i.e., liquid or gas in a body cavity. 
     BACKGROUND OF INVENTION 
     Drainage catheters are utilized for percutaneous removal of accumulated fluids from body cavities such as the peritoneal cavity or the pleural cavity. Such fluids include ascites or pleural fluid that accumulates as a result of malignancies. The accumulated fluids may cause a variety of symptoms such as chest pain, shortness of breath, nausea, non-productive cough, fever, weight loss and the like. While such fluid removal is not curative, per se, it is palliative to the patient and needs to be done repeatedly. 
     Preferably such palliative drainage can be achieved percutaneously by the placement of a tunneled peritoneal or pleural catheter. 
     Currently available drainage catheters are straight catheters that, during implantation, often slide up along the pleural wall so that only a few, if any, side drain apertures remain immersed in the pleural fluid. The drainage catheter of the present invention avoids or at least minimizes such shortcomings and provides a catheter that remains properly positioned after implantation and does not apply pressure on the adjacent tissue. 
     SUMMARY OF INVENTION 
     A catheter of the present invention is an elongated, flexible tube of uniform diameter that defines a lumen and terminates at its distal portion in a normally spiroidal configuration, preferably as a substantially planar coil. The flexible tube is provided with a subcutaneous cuff on the exterior of the tube. 
     The spiroidal distal portion is provided with a plurality of spaced drain apertures that provide fluid communication between exterior of the coiled portion of the flexible tube and the lumen. The distal portion, in its normal, spiroidal configuration is substantially centered with respect to the adjacent midportion of the flexible tube. 
     A midportion of the flexible tube is provided with at least one pair of opposed offsets, each less than 90 degrees, situated in the region between the subcutaneous cuff and the coil. The first offset of the tube preferably is at about 20 degrees to about 75 degrees, more preferably is at about 45 degrees to the plane of the spiroidal distal portion. The second offset is opposite to the first offset and is at about the same angle relative to a plane substantially parallel to but spaced from the plane of the spiroidal distal portion. The sum effect of these two offsets is a relocation of the proximal part of the flexible tube to a new path parallel to the plane of the distal portion of the flexible tube. These two offsets oppose one another, and are spaced from one another about six tube diameters. The second offset is situated about five tube diameters from the subcutaneous cuff. 
     For implantation, the normally spiroidal distal portion, as well as the two offsets, are temporarily straightened by introducing into the lumen of the flexible tube a stiffening rod and then the resulting, temporarily straightened catheter is introduced via an appropriate incision into the targeted body cavity. For implantation into the pleural cavity, an incision can be made between adjacent ribs of the patient&#39;s rib cage in a direction superiorly and posteriorly toward the pleural space. For implantation into the peritoneal cavity, the temporarily straightened catheter is inserted through an incision in the abdominal wall and advanced into the peritoneum. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  is a top view of a drainage catheter embodying the present invention; 
         FIG. 2  is a side elevational view of the drainage catheter shown in  FIG. 1 ; 
         FIG. 3  is a top view of the drainage catheter, temporarily straightened preparatory to implantation; 
         FIG. 4  is an enlarged cross-sectional view of the catheter of  FIG. 3  taken along plane  4 - 4 ; 
         FIG. 5  is an enlarged cross-sectional view of the catheter of  FIG. 3  taken along plane  5 - 5 ; and 
         FIG. 6  is an enlarged agmentary view of a temporarily straightened distal portion of a catheter embodying the present invention and illustrating a preferred arrangement of drain apertures. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , drainage catheter  10  includes an elongated, flexible tube  12  of substantially uniform diameter which has a proximal portion  14 , a midportion  16 , and a distal portion  18 . Tube  12  defines a lumen  24  ( FIGS. 4 and 5 ). 
     In its normal configuration, distal portion  18  of catheter  10  is in the form of substantially planar coil  20 . For purposes of introduction or implantation into a body cavity of a patient in need of a catheter or fluid drainage, coil  20  can be temporarily straightened as shown in  FIG. 3  by inserting into the lumen thereof a relatively stiffer member such as a stylette and the like. 
     In normal, operational configuration, i.e., after implantation and stylette removal, catheter  10  returns to the shape shown in  FIGS. 1 and 2 , with coil  20  substantially centered with respect to midportion  16  of tube  12  as shown in  FIG. 1 . After resuming normal spiroidal configuration, the outer diameter of coil  20  is about 10 to 18 outside diameters of flexible tube  12 . The curvature for coil  20  is progressively increasing from the distal end of the coil, i.e., the coil gets progressively larger. Coil  20  also is the distal end portion of flexible tube  12 . The radial dimension of the curvature along the coil preferably is in the range of about 5 to about 9 outside diameters of flexible tube  12 . 
     The outside diameter of the flexible tube usually is in the range of about 6.5 millimeters to about 2.5 millimeters, preferably about 5.5 millimeters to about 3.5 millimeters, although the outside diameter can be larger or smaller as deemed appropriate. For an adult drainage catheter, a particularly preferred outside diameter of the flexible tube is about 5 millimeters, and for a pediatric drainage catheter the preferred outside diameter is about 3.7 millimeters. 
     Likewise, the inside diameter of the flexible tube (i.e., the lumen diameter) usually is in the range of about 5 millimeters to about 1.5 millimeters, preferably about 3.8 millimeters to about 2.3 millimeters, although the inside diameter can be larger or smaller as deemed appropriate. For an adult drainage catheter, the preferred inside diameter is about 3.7 millimeters, and for a pediatric drainage catheter the preferred inside diameter is about 2.5 millimeters. 
     The flexible tube  12  at midportion  16  thereof has at least one cuff  22  permanently affixed to the exterior of flexible tube  12 . The function of cuff  22  is to enable body tissue to grow into the material of the cuff, thereby securing the catheter to the patient after implantation and also thereby to become an effective barrier to external bacteria and potential infection. Typically one cuff, such as cuff  22  shown in  FIG. 2  is sufficient; however, more than one cuff can be provided, if desired. 
     In the region of midportion  16  there is provided a pair of opposed offsets  26  and  28  as best seen in  FIG. 2 . Offset  26  is defined by flexible tube  12  bent at an angle of about 45 degrees relative to the place of coil  20 , and offset  28  is defined by flexible tube  12  bent at an angle of about 45 degrees relative to a plane substantially parallel to but spaced from the plane of coil  20 . Stated in another way, at both offsets  26  and  28  flexible tube  12  form an included angle of about 135 degrees. Offset  26  is typically spaced about five tube outside diameters from cuff  22 . Offset  26  and offset  28  are commonly spaced from one another about 6 tube outside diameters. It is understood that the dimensions can be altered as deemed appropriate. The dimensions may very from 2 to 8 tube diameters as deemed appropriate. The offset angle is less than 90 degree, preferably about 20 to about 75 degrees more preferably about 45 degrees. If desired, a cuff such as cuff  22  can be situated between the offsets, or such a cuff provided in addition to cuff  22 . More than one pair of opposed offsets can be provided, if desired. 
     A radiopaque stripe  30  extends along the length of tube  20  as shown in  FIGS. 3 ,  4 ,  5  and  6 . Radiopaque stripe  30 , usually barium sulfate U.S.P., by nature opaque white, with or without added contrasting colorant, preferably blue, permits monitoring catheter  10  position during and after implantation. 
     Distal end  32  of catheter  10  is open to permit passage of the fluid to be drained or infused. Distal portion  18  also is provided with an array of spaced apertures  34  for the same purpose. The aperture rows can be offset longitudinally along tube  12  in the coiled portion thereof ( FIGS. 1 and 3 ) as well as radially about the periphery of tube  12  ( FIG. 4 ). The positionings, spacing and distribution of apertures  34  can vary as desired. Usually the apertures have a diameter in the range of about 0.9 to about 1.2 millimeters. A preferred array of apertures  34  is illustrated in  FIG. 6  where apertures  34  are arranged into four rows, peripherally spaced and with each row offset relative to an adjacent row, the apertures having a diameter of about 1.1 mm in a flexible tube  12  having an outside diameter of about 5.1 millimeters, spaced longitudinally at about 5 to about 15 mm intervals, preferably at about 10 mm intervals, and spaced radially about 90 degrees from one another about the periphery of tube  12  (see  FIG. 4 ). 
     Flexible tube  12  preferably is made of medical grade silicone tubing, e.g., NuSil-Med 4750/4755. Preferred material of construction for subcutaneous cuff  22  is polyester felt bonded to flexible tube  12  by an appropriate adhesive. In the case of medical grade silicone tubing a preferred silicone adhesive is ethyltriacetoxysilane filled with amorphous silica, and the like, commercially available under the designation Nusil MED-1511 from NuSil Technology, Inc., Carpenteria, Calif., U.S.A. 
     For pleural fluid drainage, a catheter embodying the present invention is implanted into the pleural cavity. Several surgical pleural catheter implantation techniques can be utilized. However, the most common method is what is called the Modified Seldinger Technique. The original Seldinger technique, is defined as a technique “ . . . for percutaneous puncture of arteries or veins, used in angiography.” See, for example, Dorland&#39;s Illustrated Medical Dictionary, 25 th  ed., W.B. Saunders Co., Philadelphia, Pa. (1974) p. 1543. 
     There are a few variations on the Modified Seldinger approach that are suitable for use with this present invention. All versions of this technique are always performed in an aseptic manner in one of several locations, including the operating room (theatre), intensive care unit (ICU), hospital outpatient facility (surgery, laparoscopy, or radiology sites), or a suitably equipped doctor&#39;s office. The medical specialists who implant these catheters include thoracic surgeons, interventional radiologists, and interventional pulmonologists. 
     The patient is admitted to the implantation facility. Pre-operative sedation (conscious sedation) is commonly administered. Blood pressure, oximetry, and cardiac monitoring are commonly performed throughout the implantation procedure. Some specialists monitor only one of the above indicators, and some do not monitor these indicators at all. The skin is prepped in a manner typical of all invasive percutaneous techniques. A localized injection of 1% lidocaine is administered in the midaxiallary line, typically “ . . . at 1-2 rib interspaces below the level of dullness to percussion determined during the physical examination.” [Rubins J., “Pleural Effusion,” Peters et al., eds., Emedicine (2008) accessible online at the website emedicine.com/med/topic1843.htm: article updated 5 Jun. 2008; accessed 12 Aug. 2008.). Site location may also be confirmed by use of radiography, ultrasound, or CT scan. A larger bore needle, typically 18 gauge, is inserted into the pleural space at a “ . . . slight posterior angalation.” [Pollak J S, et al., J. Vasc. Interv. Radial. 12(2): 201-8 (2001)]. An outflow of pleural fluid confirms successful entry into the pleural cavity. A 0.038-inch braided guide wire is inserted into and through the needle into the pleural cavity. The needle is withdrawn over the wire. 
     The proximal end of the guide wire is inserted into the distal, narrow end of the expandable Luke™ Guide (3.0 mm dia., 9 Fr), or a standard split sheath with dilator (6.7 mm dia., 20 Fr), and out of the proximal end of the Guide. The Luke™ Guide is inserted into the pleural cavity over the guide wire, following it into the pleural space. The wire is removed, leaving the Guide in place. The Luke™ Guide is secured by clamping the tab of the Guide with a hemostat. The Guide is dilated with the small dilator (4.6 mm; 14 Fr). A larger dilator (6.4 mm; 19 Fr) is used only as necessary, if a lot of resistance is felt while dilating the Guide with the small diameter dilator. 
     The catheter stylette (stiffening rod) is lubricated with sterile surgical lubricating gel or sterile saline, and inserted into the catheter from the proximal end to the distal end. The stylette temporarily straightens the catheter and also makes it stiff enough to be inserted through the Luke™ Guide into the pleural cavity. 
     Lubricating gel is applied to the distal end of the catheter. The catheter is inserted into the Guide, with the radiopaque stripe facing upwards (relative to the torso) so that the plan of the coil is correctly oriented in the pleural space. This is true for both left- and right-side placements. When the catheter is inserted, the practitioner must not insert more than 5.0-7.0 cm (2.0-3.0 in) at one time, without retracting the stylette. While holding the stylette stationary, the practitioner then slides the catheter off the stylette and into the pleural cavity, always keeping the radiopaque stripe in the same position. 
     The physician continues to advance the catheter so that the catheter offset is within the intercostal space (i.e., between the ribs). The stylette is then removed and the cap is temporarily affixed to the end of the catheter to temporarily stop fluid drainage. The catheter is checked and adjusted if necessary to ensure (1) that the radiopaque stripe is in the correct position; and (2) that the catheter offset is within the intercostal space. 
     The external part of the pleural catheter is tunneled under the patient&#39;s skin so that the proposed skin exit-site for the external part of the catheter has a slight downward-facing bend from the implantation site. The catheter is tunneled out through the subcutaneous tissue and out of the skin. 
     The practitioner continually ensures during the tunneling process that the radiopaque stripe is not twisted, and that the offset part of the catheter is not dislodged from the intercostal space. 
     After the catheter has been tunneled, a catheter connector, with its one-way valve, is inserted into the distal catheter end. The entire length of the visible catheter segment is inspected to verify correct positioning and to ensure that the catheter is not twisted. The primary incision site is then closed in the typical manner, and dressed appropriately. There is no need for a suture to be placed at the exit-site. Only appropriate dressing and tape is to be used at the exit-site itself to immobilize the catheter and to protect the exit-site. 
     The sterile lid of the drain/vacuum canister set with its two attached sterile tubes is then attached to the catheter and to the vacuum pump. 
     When sufficient fluid has been drained off (maximum 1.5 L for pleural fluid; 3.0-5.0 L for ascites fluid), the pump is turned off. The respective tubes are disconnected. The catheter valve end is wiped with isopropyl alcohol, and a sterile protective cap is attached. The catheter is secured to the patient with dressing and tape. The collected fluid, canister, and tubing lines are discarded as per standard aseptic procedures. 
     The implantation instructions described above are typical for insertion of this catheter into the pleural cavity. The instructions to implant this catheter into the abdominal cavity are similar, and are known to the practitioner. 
     The major difference is the location of the implantation site. While there are a number of suitable abdominal sites, the most commonly selected site is approximately 3 cm from the patient&#39;s midline and approximately 15 cm above the pubic symphysis. 
     There are a number of techniques which can be used to implant this catheter into the abdominal cavity, including general surgery (cut-down), laparoscopy, and Modified Seldinger Technique. Practitioners are familiar with the details, merits, and weaknesses of each technique, and are to choose the one most suitable for the patient. 
     Tunneling the catheter is done in the manner described above for tunneling the pleural catheter. The balance of the procedure for the ascites catheter mimics that used for the pleural catheter. 
     The foregoing description and the drawings are illustrative, and are not to be taken as limiting. Still other variations of the described catheter are possible and will readily present themselves to those skilled in the art.