Patent Publication Number: US-2021178118-A1

Title: Multi-catheter infusion system and method thereof

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a multi-catheter infusion system used for the administration of local anesthetics or other fluids (including but not limited to antibiotics or pain relief drugs) to a patient. In particular, the present invention provides a multi-catheter infusion system and method thereof for the localized delivery of e.g., medications over extended periods of time and near a wound site while minimally affecting patient mobility over an extended period of time. 
     Current methods of drug delivery to a wound site use multiple, divided injections of local anesthetics into tissue surrounding the wound, such as peri-articular injections after total joint arthroplasty, and have been shown to improve post-operative pain control and facilitate mobility. These injections are traditionally performed by surgeons at the end of the procedure, are easy to perform and require little training. However, such methods are disadvantageous in that they have limited time of action, which in part depends on the local anesthetic used. 
     Although recently longer acting formulations of local anesthetics have become available, their efficacy is still unknown, and little is known at this time regarding infection risk, potential for neuro and tissue toxicity or any other long-term side effects. Further, once injected the length of action, duration, and strength of the anesthetic cannot be controlled or adjusted. Moreover, the type of infusion cannot be adjusted. 
     Thus, there is still a need to address the foregoing limitations of conventional drug delivery systems, such as limited time of action and the need for multiple injections into tissue surrounding the wound. Such a need is satisfied by the present invention. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with a preferred embodiment, the present invention provides a multi-catheter infusion system that includes a cannula having a first end for connecting to a drug delivery system and a second end opposite the first end. The system further includes a plurality of catheters attached to the second end in fluid communication with the cannula for delivering a drug to a target area of a patient. Each catheter includes a multi-orifice distal end. The second end of the cannula includes a regulator. The regulator can be a flow regulator or a pressure regulator. The cannula is flexible and further includes a detachable needle for facilitating the positioning of the multi-catheter infusion system. Additionally, the cannula has a cross-sectional diameter greater than an overall diameter of the plurality of catheters. 
     The plurality of catheters are attached to the second end downstream the regulator. Moreover, the plurality of catheters are about 5-10 inches in length and each catheter is about 28-15 gauge in diameter. Each of the plurality of catheters may alternatively be configured to have a cross-sectional diameter sufficient to draw fluid from the cannula by capillary action. The distal end of each of the plurality of catheters has a closed distal face. The distal end of the each of the plurality of catheters further includes a needle that is detachable from the catheter. Further, the distal end of each of the plurality of catheters includes a weakened portion for detaching the needle from each catheter. Furthermore, the multi-orifices of the distal end extend about 0.1-2 inches. 
     In accordance with another preferred embodiment, the present invention provides a method for delivery of a drug to a patient. The method includes inserting a multi-catheter infusion system having a cannula and a plurality of catheters extending from the cannula through a patient&#39;s skin such that the plurality of catheters are positioned underneath the skin, positioning each of the plurality of catheters to a predetermined location, and delivering a drug to the patient through the multi-catheter infusion system. Further, the step of inserting the multi-catheter infusion system through the patient&#39;s skin includes detaching a guide needle from the cannula. 
     The method further comprises securing a distal end of each of the plurality of catheters to a desired location by passing the distal end through soft tissue at the desired location. Moreover, the distal end of each of the plurality of catheters includes a needle. Further, the method comprises detaching the needle from each of the plurality of catheters after passing the distal end through soft tissue at the desired location. Furthermore, the method comprises withdrawing the multi-catheter infusion system from the patient by directly pulling the multi-catheter infusion system through the patient&#39;s skin. 
     In accordance with an aspect, the present invention provides a multi-catheter infusion system having an external cannula that would be connected to a medication delivery system on one side and the other side with multiple catheters. The placement of catheters, that would deliver drug to the target area under the skin of the patient under direct vision, would be facilitated by an attached hook-shaped needle that is detached after positioning. This leaves the multi-orifice, closed tip catheter in situ. A regulator is attached to gauge the infusion pressure and regulate the amount of fluid entering the patient. 
     In accordance with another aspect, the multi-catheter infusion system includes an external, larger bore cannula that would be connected to a medication delivery system such as a pump. The placement of this portion through the skin of the patient would be facilitated by an attached needle that is being cut off after placement. A universal connector connecting this portion of the cannula to an external drug delivery system will then be attached. The opposite end of this cannula would end in a hub giving rise to multiple smaller catheters that can be placed individually at various desired locations in the surgical field under direct vision. Placement of catheters (as well as the cannula) will be facilitated by needles at the end of the catheters that can be cut after placement. The distal part of the cannula including the transition area to the smaller catheters would be positioned under the level of the skin as to represent only one entry site into the patient&#39;s body. Different versions varying in the length and number of the catheters could allow for the placement according to the area to be covered. Catheters will be multi-orifice at their distal end to allow the infusion to be disbursed effectively. The multi-catheter infusion system will be removable easily as there is no active anchoring. 
     The multi-catheter infusion system can be implanted in the patient during the surgical procedure at the point immediately before wound closure. The surgeon would choose a convenient skin exit site for the external cannula and pass the needle attached to the cannula from the inside of the wound through the skin to the outside in a manner that the regulator and attached plurality of catheters remain under the skin. The needle attached at the end of the cannula is cut and a universal connector for eventual connection to a drug delivery system is attached. Under the direct field of vision, the surgeon places the catheters at the desired locations of drug delivery. In order to accomplish this, the hook-shaped needle at a distal end of each catheter is placed with a needle driver in the desired location. Specifically, the needle is driven through the desired tissue and the cannula is subsequently pulled through. Once anchored in the desired location, the needle tip is cut within the distal, solid portion thus yielding a closed-tip multi-orifice catheter. This step is repeated for each additional catheter until each of the plurality of catheters is anchored to the tissue. 
     At this point, the surgeon may choose to inject a small amount of local anesthetic or other desired medications and observe the distribution of fluid under direct vision, to inspect that everything is operational. The wound is subsequently closed in a routine manner. The cannula exit site is dressed in a sterile fashion as routinely done during similar routine surgical procedures. Alternatively, the surgeon may choose to suture the cannula in place or leave the cannula unanchored (i.e., kept in place by tissue anchoring alone). After completion of the surgical procedure, the external cannula is connected to a drug delivery system or infusion pump by a nurse or an assistant. The multi-catheter infusion system may remain in place as long as desired. Typically, this period can be about 1-4 days or longer, with regular daily inspections at the insertion site for signs of infection. Additionally, the infusion can be titrated according to the patient&#39;s needs, per a doctor&#39;s instructions. Finally, when removal of the multi-catheter infusion system is desired the cannula is simply pulled through the insertion site with steady traction. 
     The present invention provides an improved multi-catheter infusion system that would allow for targeted administration of local anesthetics or other drug fluids, for example to provide prolonged and titratable analgesia while minimally affecting patient mobility. Periarticular analgesia and wounds covering large areas may be especially amenable to such a technique. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of the preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
       In the drawings: 
         FIG. 1  is a perspective view of a multi-catheter infusion system in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is another perspective view of the multi-catheter infusion system of  FIG. 1  connected to a drug delivery system; 
         FIG. 3  is an enlarged partial perspective view of the multi-catheter infusion system of  FIG. 1 ; 
         FIG. 4A  is an enlarged partial perspective view of a distal end of an individual catheter of the multi-catheter infusion system of  FIG. 1 ; 
         FIG. 4B  is another enlarged partial perspective view of a distal end of an individual catheter of the multi-catheter infusion system of  FIG. 1  in accordance with another aspect of the present embodiment; 
         FIGS. 5A and 5B  are front and side schematic views of the multi-catheter infusion system applied to a wound site of a patient; 
         FIG. 6  is an enlarged partial perspective view of the multi-catheter infusion system of  FIG. 1  positioned about a wound site of a patient; 
         FIGS. 6A-6C  are enlarged partial views of various ends of the multi-catheter infusion system of  FIG. 6  positioned about a wound site of a patient; 
         FIG. 7A  is a partial cross-sectional view of a flow regulator applicable to the multi-catheter infusion system of  FIG. 1 ; and 
         FIG. 7B  is a partial cross-sectional view of a pressure regulator applicable to the multi-catheter infusion system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the invention illustrated in the accompanying drawings. Wherever possible, the same or like reference numbers will be used throughout the drawings to refer to the same or like features. It should be noted that the drawings are in simplified form and are not drawn to precise scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directional terms such as top, bottom, above, below and diagonal, are used with respect to the accompanying drawings. Such directional terms used in conjunction with the following description of the drawings should not be construed to limit the scope of the invention in any manner not explicitly set forth. Additionally, the term “a,” as used in the specification, means “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import. 
     “About” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, and ±0.1% from the specified value, as such variations are appropriate. 
     In accordance with a preferred embodiment, the present invention provides a multi-catheter infusion system  5  as configured in  FIGS. 1 and 2 . The multi-catheter infusion system  5  includes a cannula  10  and a plurality of catheters  12 . The cannula  10  includes a first end  10   a  for connecting to a drug delivery system  14  and a second end  10   b  opposite the first end. 
     The cannula  10  can be any cannula suitable for its intended purpose. For example, the cannula can be any tubular or elongated vessel member for delivering fluids. Preferably, the cannula  10  is configured as a flexible elongated tubular member. The cannula  10  is also preferably configured to have a cross-sectional diameter greater than an overall diameter or width of the plurality of catheters  12  when collectively assembled. The cannula can be about 4-40 inches in length and preferably about 6-24 inches in length and more preferably about 8-18 inches in length. 
     The cannula  10  can be formed from any suitable material, such as silicone, latex, a plastic e.g., polyurethane, polyethylene, polyvinylchloride, polypropylene, polytetrafluoroethylene and nylon, and the like. 
     The cannula  10  includes a guide needle  16  for facilitating the positioning of the multi-catheter infusion system  5 . The guide needle  16  is attached to the first end  10   a  of the cannula  10 . As shown, the guide needle  16  is preferably hook shaped, but can alternatively be any shape suitable for facilitating placement of the cannula  10  through the patient&#39;s skin. The guide needle  16  is also configured to be detachable from the cannula  10 . For example, the guide needle  16  can be detachably connected via a pressure fit hub, a luer fitting, a luer adapter  17 , and the like. 
     The multicatheter infusion system also includes a universal adapter  18  for attaching to the first end  10   a  of the cannula  10  after the guide needle is removed from the cannula. The universal adapter  18  can be e.g., a luer adapter, a luer fitting, a hub and the like. 
     The drug delivery system  14  can be any drug delivery system capable of delivering fluid to the multi-catheter infusion system. For example, the drug delivery system can be a pump, a syringe, an IV bag, etc. The drug delivery system can also be a stationary or portable device. The drug delivery system  14  is capable of delivering a drug e.g., an analgesic, anti-inflammatory agents, antibiotics, nutrients, medications, hormones and the like, to the multi-catheter infusion system. In an aspect of the present embodiment, elution of the drug is preferably delivered at a pressure of 15-25 mmHg. 
     As shown in  FIG. 2 , the drug delivery system  14  includes a port  19  for connecting to the cannula  10  via the universal adapter  18 . Such drug delivery systems applicable to the present multi-catheter infusion system are known in the art and therefore a further detailed description of their structure, function and operation is not necessary for a complete understanding of the present invention. 
     The plurality of catheters  12  is attached to the second end  10   b  of the cannula  10  opposite the first end  10   a . The plurality of catheters  12  is in fluid communication with the cannula  10  for delivering a fluid e.g., a drug to a target area of a patient. Each catheter  12  includes a multi-orifice distal end  24 . 
     In accordance with an aspect of the present embodiment, the second end  10   b  of the cannula  10  includes a regulator  20  for regulating the fluid flowing through the cannula  10  and reaching the plurality of catheters  12 . The regulator  20  can be a pressure regulator  20 ′ ( FIG. 7B ) or a flow regulator  20 ″ ( FIG. 7A ). 
       FIG. 7A  illustrates the regulator  20  configured as a flow regulator  20 ″ having a valve  32  for regulating the flow of fluid regulation through the cannula. Additional flow regulators applicable to the present embodiment are disclosed in U.S. Pat. Pub. Nos. 2015/0018758 and 2002/0193751, the entire disclosures of which are hereby incorporated by reference in their entirety for all purposes. Additionally, applicable flow regulator to the present embodiment include e.g. the Harion™ dial flow regulator by Harsonia Healthcare PVT LTD. of Udyog Vihar, Gurgaon, Haryana, India and the STAT 2® IV Gravity Flow controller by CONMED of Utica, N.Y. 
       FIG. 7B  illustrates the regulator  20  configured as a pressure regulator  20 ′ having a globe valve  34  configuration. Alternatively, the pressure regulator  20 ″ can be configured as any other pressure regulator suitable for cannulas or tubing, as readily known in the art. 
     Referring to  FIG. 3 , the regulator  20  can be sized to have an overall diameter matching or the same as the cannula  10 , so as to easily remove the multi-catheter infusion system through a patient&#39;s skin. Alternatively, the regulator can be sized to have a diameter differing from the cannula, e.g., larger, than the cannula, as shown in  FIG. 2 , with a tapered portion to facilitate removal of the multi-catheter infusion system through a patient&#39;s skin. 
     The plurality of catheters  12  are preferably attached to the second end of the cannula  10  downstream the regulator  20 . The plurality of catheters  12  can be any catheter suitable for its intended purpose. For example, each of the plurality of catheters  12  can be any tubular member on elongated vessel for delivering fluids. Preferably, each catheter is configured as a flexible elongated tubular member. 
       FIG. 1  illustrates the multi-catheter infusion system having five catheters attached to the cannula  10 . However, the number of catheters attached to the cannula can be more or less than five, for example, 2, 3, 4, 6, 7, 8, 9, 10 or more catheters. 
     The catheters  12  can be formed from any suitable material, such as silicone, latex, a plastic e.g., polyurethane, polyethylene, polyvinylchloride, polytetrafluoroethylene, polypropylene, nylon, and the like. 
     Preferably, each of the plurality of catheters  12  is about 28-15 gauge in diameter. In every configuration, the diameter of each of the plurality of catheters  12  is less than the diameter of the cannula  10 . Collectively, the plurality of catheters  12  have an overall diameter or width when assembled together that is less than a cross-sectional diameter of the cannula  10 . Each of the plurality of catheters  12  is also preferably configured to have a length from about 5-10 inches but can be more or less than 5-10 inches such as 2, 4, 12, 14, 16, 18, 20, 22 and 24 or more inches, depending on the type of wound, location of the wound, and size of the wound area. Additionally, each of the plurality of catheters can be configured to have the same overall length or varying lengths e.g., 5 inches, 7 inches, and 9 inches. 
     Further, in accordance with another aspect, each of the plurality of catheters  12  can be configured to have a cross-sectional diameter sufficient to draw fluid from the cannula  10  by capillary action. For example, when the drug is traveling to the cannula  10 , the narrower diameter of the catheters will cause the drug to flow through the plurality of catheters under capillary action as opposed to positive pressure forcing fluid flow through the catheters. 
     As shown in  FIG. 4A , each catheter  12  includes a multi-orifice distal end  24 . The multi-orifice distal end  24  includes a series of perforations or orifices  26  to permit flow laterally out of the catheter  12  i.e., about the sides of the catheter, into the various locations targeted for drug delivery. Preferably, the orifices  26  of the distal end are configured to extend about 0.1-2.0 inches from the most distal end of the catheter. 
     The orifices  26  can be arranged symmetrically spaced across a periphery of the catheter  12 , as shown in  FIG. 4A . The number of orifices  26  or specific arrangement of orifices  26  can also vary i.e. be staggeredly positioned, or equally spaced apart. Further, the number, spacing and size of the orifices  26  can vary based on a location, size and type of the wound site being treated. 
     For example, in accordance with an aspect of the present embodiment as shown in  FIG. 4B , the orifices  26  can be positioned about the distal end of the catheter so as to be spirally arranged. In this configuration each opening of an orifice spans a circumference of the catheter partially overlapping an adjacent orifice thereby allowing for uniform coverage of fluid dispersion in a radial direction. That is e.g., the circumferential span of orifice  26   a  overlaps the circumferential span of orifice  26   b . This overlap is continued throughout the spiral arrangement so that 360° of circumferential coverage by the orifices is achieved. 
     The orifices  26  are preferably circular in shape, but can alternatively be configured in other suitable shape e.g., ovular, square, triangular, trapezoidal, parallelogram, and other irregular shapes. They can also vary in size and number of orifices. However, the number of orifices should be sufficient to achieve a desired elution rate. 
     Referring back to  FIG. 4A , the distal end of each of the plurality of catheters  12  includes a needle  28 . The needle  28  is preferably hook shaped, but can alternatively be any shaped needle capable of piercing soft tissue for anchoring or securing the distal end of the catheter  12  to a target delivery area of the patient. That is, the needle  28  on each of the plurality of catheters  12  is used to drive through soft tissue at the desired location with a needle driving instrument (not shown) so that the distal end portion of the catheter is anchored in position by soft tissue alone. 
     The distal end of each of the plurality of catheters  12  includes a closed distal face. The distal end is closed by a plug  29  for sealing off the distal face of the catheter such that fluid flows out of the catheters only through the orifices  26  under uniform pressure or distribution. The plug  29  further prevents debris and tissue from entering each catheter about its distal face. 
     The plug  29  can be formed out of any suitable material, such as a plastic, an elastomer, silicone, latex and the like. Preferably, the plug is formed out of a rigid plastic for supporting the needle  28  and providing a weakened portion  30  for detaching the needle from the plug, as further discussed below. 
     The plug  29  includes a weakened portion  30  to allow a user to breakaway or detach the needle from the plug. The weakened portion  30  can be a notch, a slit, a perforation, a scored section and the like. The weakened portion  30  is a portion of the plug that has e.g., a weaker tensile or yield strength, or can fracture and breakaway under a lower applied load compared to the remainder of the plug. This feature allows the user to detach the needle from the plug after anchoring the distal end of the catheter to soft tissue, as further described below. 
     The plug  29  also includes a cone or cone-like shaped head about which the needle  28  is attached to. The cone shaped head facilitates traversing the distal end of the catheter through soft tissue. 
     The present invention also provides a method for delivering a drug to a patient. The method includes inserting the multi-catheter infusion system having the cannula  10  and the plurality of catheters  12  extending from the cannula  10  through a patient&#39;s skin. The multi-catheter infusion system  5  is implanted in the patient during a surgical procedure at a point immediately before wound closure. Specifically, a predetermined convenient skin exit site is chosen and the guide needle  16  attached to the cannula  10  is passed from the inside of a wound through the skin to the outside in a manner, such that the plurality of catheters  12  are positioned underneath the skin. Thereafter, the guide needle  16  is detached from the cannula  10 . After detaching the guide needle  16 , the cannula  10  is connected to the universal adapter  18  for connecting the cannula  10  to the drug delivery system  14 , as shown in  FIG. 2 . 
     The present method further includes positioning each of the plurality of catheters  12  to a predetermined location. The predetermined location being a location determined by the user or based on a set positioning scheme from the wound. In order to position each of the catheters  12 , the distal end of each of the plurality of catheters  12  is set to a desired location by passing the distal end through soft tissue at the desired location. This is accomplished by using a needle driver to drive the needle  28  at the distal end of each catheter  12  through soft tissue at the desired locations. After passing the distal end through soft tissue at the desired location, the needle  28  is detached from each of the plurality of catheters  12 , by conventional means such as scissors or the like. Each catheter is then anchored in position by soft tissue only. 
       FIG. 6  illustrates the multi-catheter infusion system  5  as applied to a generic wound site  100 . The multi-catheter infusion system  5  is shown implanted under the skin in tissue near the wound site  100 , with the distal ends of individual catheters in various stages of anchoring as shown in  FIGS. 6A-C .  FIG. 6A  shows a distal end of a catheter  12  prior to being anchored into tissue at a desired location.  FIG. 6B  illustrates the catheter  12  is shown passed through a tissue portion for anchoring.  FIG. 6C  illustrates the distal end of the catheter  12  at the desired location with the needle  28  removed. 
     After all catheters are anchored in position, the wound is closed and the cannula exit site is sterilized in a routine manner. Subsequently, the cannula is connected to the drug delivery system. Drugs are delivered to the patient through the multi-catheter infusion system over an extended period of time. At the conclusion of drug delivery to the patient, the multi-catheter infusion system is withdrawn from the patient by directly pulling the multi-catheter infusion system through the patient&#39;s skin. Owing to the tissue anchored ends of the catheters (as shown in  FIGS. 6A-C ), the multi-catheter infusion system can advantageously be removable easily from the patient. 
       FIGS. 5A and 5B  illustrate the multi-catheter infusion system  5  as applied in use to a wound site of a patient, for example, around the patient&#39;s knee, and attached to a drug delivery system  14 ′. The drug delivery system is shown configured as a portable device which may be placed around the patient&#39;s waist. 
     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is to be understood, therefore, that this invention is not limited to the particular preferred embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.