Patent Publication Number: US-2023138669-A1

Title: Peripherally Inserted Central Catheter System Including a Stylet with Lubrication

Description:
PRIORITY 
     This application claims the benefit of priority to U.S. Provisional Application No. 63/274,468, filed Nov. 1, 2021, which is incorporated by reference in its entirety into this application. 
    
    
     BACKGROUND 
     Inserting a peripherally inserted central catheter (“PICC”) into the vasculature of the patient may involve a stylet being placed inside a lumen of the PICC to give the PICC stabilization during insertion of a PICC-stylet assembly. However, the tip of the PICC can encounter obstructions during placement, leading to buckling or a bending event of the tips of the stylet and the PICC. The bending event can lead to breaking off of the tips of the stylet and the PICC, wherein breaking off of one or more of the tips is considered a serious failure of the PICC. It would be beneficial to the patient and the clinician to have a PICC and a stylet that are not prone to a bending event, allowing the clinician to properly place the PICC without fear of PICC or stylet failure. Disclosed herein are a system, apparatus and method of manufacturing that address the foregoing. 
     SUMMARY 
     Disclosed herein is catheter assembly, that according to some embodiments, includes a catheter defining a catheter proximal end and a catheter distal end, where the catheter defines a central lumen extending between the catheter distal end and a catheter connector at the catheter proximal end. The catheter assembly further includes aa stylet inserted into the central lumen where the stylet includes (i) a stylet tube defining a tube lumen extending along the stylet tube between a stylet proximal end and a stylet distal end, (ii) a plurality of magnets disposed within the tube lumen, and (iii) a lubricant disposed between one or more of the plurality of magnets and an inner surface of the stylet tube such that the lubricant enables sliding motion the one or more of the plurality of magnets with respect to the stylet tube. 
     In some embodiments, the catheter is a peripherally inserted central catheter. In some embodiments, the catheter includes two or more extension legs, each extension leg defining an extension leg lumen in fluid communication with the central lumen. 
     In some embodiments, the stylet tube includes a polyamide material. 
     In some embodiments, the lubricant is disposed between the plurality of magnets and an inner surface of the stylet tube. In some embodiments, the lubricant extends between adjacent magnets of the plurality of magnets. 
     In some embodiments, the plurality of magnets are disposed along a magnetic region of the stylet, where the magnetic region extends proximally away from the stylet distal end. In some embodiments, the lubricant is disposed along the magnetic region. In some embodiments, the lubricant is disposed along a portion of the stylet tube extending proximally away from the magnetic region. 
     In some embodiments, each of the magnets is cylindrically shaped, and the plurality of magnets are arranged end-to-end along the magnetic region. In some embodiments, each of the magnets includes a parylene coating. 
     In some embodiments, the stylet includes a stainless steel wire disposed within the tube lumen, where the wire extends longitudinally along at least the magnetic region. In some embodiments, the wire is wrapped at least partially around each magnet. 
     In some embodiments, the stylet includes one or more sensors configured to detect electrical signals and, in some embodiments, the one or more sensors includes an electrode disposed at the distal end of the stylet, where the electrode is electrically coupled with the wire. 
     In some embodiments, the lubricant is water soluble, and in some embodiments, the lubricant includes a biologic agent. 
     In some embodiments, the stylet includes an attachment member configured to couple with a catheter connector. In some embodiments, the attachment member includes a male Luer taper configured engage a female Luer taper of the catheter connector. 
     In some embodiments, a first distance between the attachment member and the stylet distal end is substantially equal to a second distance between the catheter connector and the catheter distal end such that, when the attachment member is coupled with the connector, the stylet distal end is disposed adjacent the catheter distal end. 
     Also disclosed herein is a stylet configured for insertion within a catheter that, according to some embodiments, includes (i) a stylet tube defining a tube lumen extending along the stylet tube between a stylet proximal end and a stylet distal end, (ii) a plurality of magnets disposed within the tube lumen, and (iii) a lubricant disposed between one or more of the plurality of magnets and an inner surface of the stylet tube such that the lubricant enables sliding motion the one or more of the plurality of magnets with respect to the stylet tube. 
     In some embodiments of the stylet, the stylet tube includes a polyamide material. 
     In some embodiments of the stylet, the lubricant is disposed between the plurality of magnets and an inner surface of the stylet tube and in some embodiments of the stylet, the lubricant is disposed between adjacent magnets of the plurality of magnets. 
     In some embodiments of the stylet, the plurality of magnets are disposed along a magnetic region of the stylet, where the magnetic region extends proximally away from the stylet distal end. In some embodiments of the stylet, the lubricant is disposed along the magnetic region. 
     In some embodiments, the stylet includes a stainless steel wire disposed within the tube lumen, where the stainless steel wire extends longitudinally along at least the magnetic region. In some embodiments of the stylet, the stainless steel wire is wrapped at least partially around each magnet. 
     In some embodiments, the stylet includes one or more sensors configured to detect electrical signals. In some embodiments of the stylet, the one or more sensors includes an electrode disposed at the distal end of the stylet, the electrode electrically coupled with the wire. 
     In some embodiments, the stylet includes an attachment member configured to couple with the catheter connector. 
     Also disclosed herein is a method of manufacturing a catheter assembly, where the method includes assembling a stylet, and where assembling a stylet includes (i) dispensing a lubricant within a lumen of a stylet tube, where the lubricant disposed adjacent a distal end of the stylet tube; and (ii) inserting a plurality of magnets within the lumen of the stylet tube such that the lubricant covers each of the plurality of magnets. The method further includes inserting the stylet into a central lumen of a catheter. 
     In some embodiments of the method,  33 . The method according to claim  21 , wherein the catheter includes a peripherally inserted central catheter having more than one extension leg, each extension leg including an extension leg lumen in fluid communication with the central lumen. 
     In some embodiments of the method, assembling the stylet further includes wrapping the each of the plurality of magnets with a wire, and inserting the wire into the lumen of the stylet tube. 
     In some embodiments of the method, assembling the stylet further includes (i) coupling an electrode to the stylet tube at the distal end, (ii) connecting the wire to the electrode, and (iii) extending the wire proximally beyond a proximal end of the stylet tube. 
     In some embodiments, the method further includes positioning the stylet with respect to the catheter such that the distal end of the stylet tube is disposed adjacent a distal end of the catheter. 
     In some embodiments of the method, assembling the stylet further includes threading an attachment member onto the stylet tube and securing the attachment member to the stylet tube, and the method further includes coupling the attachment member to a connector of the catheter. 
     These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and following description, which describe particular embodiments of such concepts in greater detail. 
    
    
     
       DRAWINGS 
       A more particular description of the present disclosure will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. Example embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG.  1    illustrates a perspective view of a peripherally inserted central catheter system including a peripherally inserted central catheter and a stylet, in accordance with some embodiments; 
         FIGS.  2 A- 2 B  illustrate a cross-sectional side view of the distal end of the stylet of  FIG.  1    in a bending event, in accordance with some embodiments; 
         FIG.  3 A  illustrates a detailed cross-sectional side view of the stylet, in accordance with some embodiments; 
         FIG.  3 B  illustrates a cross sectional end view of the distal end of the stylet, in accordance with some embodiments; 
         FIGS.  4 A- 4 B  illustrate a cross-sectional view of the distal end of the stylet including the lubricant in a bending event, in accordance with some embodiments; and 
         FIG.  5    illustrates a flow chart of an exemplary method of manufacturing the catheter system, in accordance with some embodiments. 
     
    
    
     DESCRIPTION 
     Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein. 
     Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     With respect to “proximal,” a “proximal portion” or a “proximal-end portion” of, for example, a catheter disclosed herein includes a portion of the catheter intended to be near a clinician when the catheter is used on a patient. Likewise, a “proximal length” of, for example, the catheter includes a length of the catheter intended to be near the clinician when the catheter is used on the patient. A “proximal end” of, for example, the catheter includes an end of the catheter intended to be near the clinician when the catheter is used on the patient. The proximal portion, the proximal-end portion, or the proximal length of the catheter can include the proximal end of the catheter; however, the proximal portion, the proximal-end portion, or the proximal length of the catheter need not include the proximal end of the catheter. That is, unless context suggests otherwise, the proximal portion, the proximal-end portion, or the proximal length of the catheter is not a terminal portion or terminal length of the catheter. 
     With respect to “distal,” a “distal portion” or a “distal-end portion” of, for example, a catheter disclosed herein includes a portion of the catheter intended to be near or in a patient when the catheter is used on the patient. Likewise, a “distal length” of, for example, the catheter includes a length of the catheter intended to be near or in the patient when the catheter is used on the patient. A “distal end” of, for example, the catheter includes an end of the catheter intended to be near or in the patient when the catheter is used on the patient. The distal portion, the distal-end portion, or the distal length of the catheter can include the distal end of the catheter; however, the distal portion, the distal-end portion, or the distal length of the catheter need not include the distal end of the catheter. That is, unless context suggests otherwise, the distal portion, the distal-end portion, or the distal length of the catheter is not a terminal portion or terminal length of the catheter. 
     The phrases “connected to,” “coupled to,” and “in communication with” refer to any form of interaction between two or more entities, including but not limited to mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be coupled to each other even though they are not in direct contact with each other. For example, two components may be coupled to each other through an intermediate component. 
     Any methods disclosed herein comprise one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. 
       FIG.  1    illustrates a perspective view of a catheter assembly (“assembly”)  100  including a catheter  120 , coupled with a stylet  140 , in accordance with some embodiments. In some embodiments, the catheter  120  includes a peripherally inserted central catheter (PICC). The catheter  120  defines a central lumen  134  extending along an elongate body  124 , and the stylet  140  is inserted into the central lumen  134 , when the stylet  140  is coupled with the catheter  120 . The catheter  120  includes a catheter connector  127  at the proximal end  129  of the catheter  120 . The catheter connector  127  is positioned a distance  120 A away from a distal end  128  of the catheter  120 . In some embodiments, the catheter connector  127  may include a female Luer taper  127 A and/or external Luer locking threads  127 B. In some embodiments, the catheter  120  includes one or more extension legs  130  coupled to a hub  122 , where the one or more extension legs  130  extend proximally away from the hub  122 , and where each extension leg defines an extension leg lumen  132  therein, and where each extension leg lumen  132  is in fluid communication with the central lumen  134 . However, it will be appreciated that in some embodiments, the assembly  100  may be designed to include PICCs having two or more lumens, which are considered to fall within the scope of this disclosure. 
     In some embodiments, the stylet  140  may be inserted through the one or more extension leg lumens  132  into the central lumen  134  to provide rigidity to the catheter  120  so as to enable insertion of the catheter  120  into the vasculature of the patient. The stylet  140  may include a plurality of magnets  148 , where the plurality of magnets  148  are configured to generate a magnetic field so that the stylet  140  is detectable and/or trackable via a magnetic tracking medical device. In some embodiments, the stylet  140  may include one or more sensors  156  (e.g., electrodes or coils) configured to detect one or more electrical signals and provide the electrical signals to a computing device. In an embodiment, the one or more sensors  156  may be configured to detect electrical signals emanating from the patient, such as an ECG signal emanating from the heart of the patient when as the stylet  140  is inserted into the vasculature of the patient. 
       FIGS.  2 A- 2 B  illustrates a cross-sectional side view a distal portion of the stylet  140  and the catheter  120  traversing a blood vessel  160  including a resistance  260 A of the blood vessel  160 , such as a curve, for example. The stylet  140  includes a stylet tube or tubing  252  extending along a length of the stylet  140 , where the tubing  252  defines a lumen  252 A and the plurality of magnets  148  is disposed within the lumen  252 A. As illustrated in  FIG.  2 A , in some embodiments, the stylet  140  is inserted into the central lumen  134  of the catheter  120 . As the catheter assembly  100  is advanced along the lumen of the blood vessel  160 , the catheter assembly  100  may encounter the resistance  260 A (e.g., the illustrated curve, an increase or decrease in blood vessel diameter, or the like). The catheter assembly  100  may be forced through the resistance  260 A, to continue advancement along the blood vessel  160 . In some instances, the distal end  244  may engage the resistance  260 A causing the stylet  140  undergo a bending event, as illustrated in  FIG.  2 B . The bending event includes the a distal portion of the stylet  140 , such as the magnetic region  243 , for example, undergoing excess strain due to the short gauge length (or short radius of curvature) of tubing  252  along the magnetic region  243 . The excess strain may cause rupturing (or tearing) of the tubing  252 , where the rupturing may cause a portion of the stylet  140 , such as a portion adjacent the distal end  244  of the stylet  140  to separate from the stylet  140  and so as to become a free particle within the blood vessel  160 . 
       FIG.  3 A  illustrates a cross-sectional side view of the stylet  140  including a distal end  244 , in accordance with some embodiments. In some embodiments, the stylet  140  includes a stylet body  342  having a proximal end  346  and the distal end  244 . In some embodiments, the stylet body  342  may include an elongate body defining a central longitudinal axis  341 . In some embodiments, the stylet  140  may include an attachment member  347  configured to detachably couple the stylet  140  to the catheter  120  via the catheter connector  127 . In some embodiments, the attachment member  347  may be configured to position the stylet  140  including the distal end  244  in an optimal position within the catheter  120 . In some embodiments, a distance  340 A between the attachment member  347  and the distal end  244  may be substantially equal to the distance  120 A (see  FIG.  1   ) such that when the stylet  140  is coupled with the catheter  120 , the distal end  244  of the stylet  140  is disposed adjacent the distal end  128  of the catheter  120 . 
     In some embodiments, the attachment member  347  may include components consistent with a male Luer lock connector. For example, the attachment member  347  may include a male Luer taper  347 A configured to engage a female Luer taper  127 A (see  FIG.  1   ) of the of the catheter connector  127 . Similarly, the attachment member  347  may include internal Luer locking threads  347 B configured to engage external Luer locking threads  127 B (see  FIG.  1   ) of the catheter connector  127 . 
     In some embodiments, the stylet body  342  may include a singular piece body or may have a multi-piece body. In some embodiments, the entire stylet body  342  may be rigid or portions of the stylet body  342  may be rigid and some portions of the stylet body  342  may be flexible. For example, a portion of the stylet body  342  extending distally away from the proximal end  346  may be more rigid than a portion of the stylet body  342  extending proximally away the distal end  244 . In some embodiments, the tubing  252  may include polyimide tubing, PVC, silicon, or the like. 
     As discussed above, the stylet  140  includes magnetic region  243  extending proximally away from the distal end  244 . The magnetic region  243  includes the plurality of magnets  148  (See  FIGS.  1 - 2 B ). In the illustrated embodiment, the plurality of magnets  148  includes four magnets  348 A- 348 D. In other embodiments, the plurality of magnets  148  may include more or less than four magnets. The magnets  348 A- 348 D are configured to generate a magnetic field detectable by a magnetic tracking medical device. In some embodiments, the magnets  348 A- 348 D may extend to the distal end  244  of the stylet  140 . In some embodiments, the magnets  348 A- 348 D may be aligned consecutively along the central longitudinal axis  341 . For example, a first magnet  348 A may be disposed adjacent the distal end  244  and a second magnet  348 B may be disposed proximal the first magnet  348 A. In some embodiments, the tubing  252  may be sheathed over the plurality of magnets  148 . In some embodiments, the magnets  348 A- 348 D may be cylindrically shaped and may be arranged end-to-end. 
     In some embodiments, the stylet  140  may include a wire  354  extending along the stylet  140 . In some embodiments, the wire  354  may extend only along the magnetic region  243 . In other embodiments, the wire  354  extend along an entire length of the stylet  140 . The wire  354  may be wrapped (i.e., coiled) at least partially around each of the magnets  348 A- 348 D. In some embodiments, the wire  354  may be wrapped (i.e., coiled) at least one full revolution around each of the magnets  348 A- 348 D. As shown, the wire  354  may be disposed within the lumen  252 A of the tubing  252 . In some embodiments, the wire  354  may be formed of stainless steel. In some embodiments, the wire  354  may be configured to secure the magnets  348 A- 348 D to the stylet  140  and/or limit longitudinal displacement of the magnets  348 A- 348 D with the lumen  252 A. In some embodiments, the wire  354  may define a separation space  352 B between adjacent magnets, such as the magnets  348 A,  348 B, for example. 
     In some embodiments, the wire  354  may be configured to propagate electrical signals along the stylet  140 . In some embodiments, proximal portion of the wire  354  may extend beyond a proximal end  346  of the stylet  140  (or more specifically the tubing  252 ), so that the wire  354  may be connected to a medical device configured to process electrical signals, such as an ECG device, for example. In some embodiments, the one or more sensors  156  may include an electrode  356 A disposed at the distal end  244  of the stylet  140  and the wire  354  may be electrically connected to the electrode  356 A. 
     In some embodiments, the stylet  140  may include a lubricant  380 , where the lubricant  380  is generally configured to enable longitudinal sliding displacement of one or more of the magnets  348 A- 348 D with respect to the tubing  252 . In some embodiments, the lubricant  380  may be disposed between a first magnet  348 A and a second magnet  348 B, the second magnet  348 B and a third magnet  348 C, and the third magnet  348 C and a fourth magnet  348 D. In some embodiments, the lubricant  380  may extend from the distal end  244  of the stylet  140  to a proximal end of the magnetic region  243 . By enabling sliding displacement of the one or more of the magnets  348 A- 348 D with respect to the tubing  252 , the lubricant  380  enables one or more of the magnets  348 A- 348 D to longitudinally displace during the bending event, thereby decreasing strain on the tubing  252  during the bending event to prevent, inhibit, or otherwise reduce the likelihood of a rupture of the tubing  252 . 
       FIG.  3 B  illustrates a cross sectional view of the stylet  140 , in accordance with some embodiments. In an embodiment, the stylet body  342  may include a multi-piece body extending to the distal end  244 . In some embodiments, each of the magnets  348 A- 348 D may define toroidal cross-section. In some embodiments, adjacent magnets may be magnetically attracted to each other. In some embodiments, the lubricant  380  may define a layer of lubrication disposed between an outer surface  349  one or more of the magnets  348 A- 348 D and an inner surface  353  of the tubing  252 . In some embodiments, the wire  354  may be disposed within the layer of the lubricant  380 . In some embodiments, the lubricant  380  may be disposed within the space  352 B between adjacent magnets, and the force of the insertion of the stylet  140  into the catheter  120  may cause the lubricant  380  to spread along the outer surface  349  of the magnets  348 A- 348 D and the inner surface  153  of the tubing  252 . The lubricant  380  may be a liquid or a semi-solid (e.g., a gel). In some embodiments, the lubricant  380  may be water soluble. In some embodiments, the lubricant  380  may include biological agent, such as a drug, for example. 
     In some embodiments, the lubricant  380  may include a composition that includes one or more of silicone oil, glycerin, hydroxyethyl cellulose, hypromellose, propylene glycol, hydroxypropyl methylcellulose, or the like. In some embodiments, the lubricant  380  is applied to the stylet  140  during the manufacturing process. In some embodiments, the lubricant  380  may include a formulation that transitions between an inert state and an active state upon movement, friction, temperature or the like. In some embodiments, the lubricant  380  may be (i) applied to the stylet  140  in the inert state and then (ii) transitioned to an active state before or during insertion of the stylet  140 . In an embodiment, the lubricant  380  may be formed of a thin solid film that liquefies upon being heated above a defined temperature, allowing the lubricant  380  to flow between the magnets  348 A- 348 D and the tubing  252 . In an embodiment, the defined temperature may be greater than 95° F. 
       FIGS.  4 A- 4 B  illustrate a cross-sectional view of the distal end  244  of the stylet  140  including the magnets  348 A- 348 D disposed along the magnetic region  243  and the lubricant  380  disposed within the lumen  252 A, in accordance with some embodiments.  FIG.  4 A  illustrates the magnetic region  243  disposed in a straight shape and  FIG.  4 B  illustrates the magnetic region  243  disposed in a curved shape resulting from a force  410  applied to a distal tip  445  of the stylet  140 , the force  410  causing a bending event. As shown by arrows  420 , independent bidirectional sliding displacement of the each of the magnets  348 A- 348 D with respect to the tube  252  may occur at-will during a bending event as a result of the reduced friction provided by the lubricant  380 . As such, the lubricant  380  inhibits sliding contact of the magnets  348 A- 348 D with the inside surface  153  from gouging or otherwise damaging the tube  252 . Similarly, the at-will independent bidirectional sliding displacement of the each of the magnets  348 A- 348 D may enable the tube  252  to bend at a larger radius of curvature, thus reducing strain in the tubing  252 , thereby further inhibiting damage to the tube  252 . 
       FIG.  5    illustrates a flow chart of an exemplary method of manufacturing of the catheter assembly, in accordance with some embodiments. The method  500  may include all or any subset of the following steps, actions, or processes. In some embodiments, the method  500  may include assembling a stylet (block  510 ). 
     Assembling the stylet may include dispensing a lubricant within a lumen of a stylet tube (block  511 ). Dispensing the lubricant may include locating the lubricant adjacent the distal end of the stylet tube, such as along the magnetic region, for example. 
     Assembling the stylet may also include inserting the plurality of magnets within the lumen of the stylet tube (block  512 ). Inserting the plurality of magnets may include locating the magnets adjacent the distal end of the stylet tube, such as along the magnetic region, for example. Dispensing the lubricant and/or inserting the magnets may include covering the magnets with the lubricant. 
     Assembling the stylet may also include wrapping the each of the plurality of magnets with a wire (block  513 ) and inserting the wire into the lumen of the stylet tube (block  514 ). 
     Assembling the stylet may also include coupling an electrode to the stylet tube (block  515 ), where the electrode is coupled to the stylet tube at the distal end. Coupling the electrode may also include connecting the wire to the electrode, and extending the wire proximally beyond a proximal end of the stylet tube. 
     Assembling the stylet may also include securing an attachment member to the stylet tube (block  516 ) to the stylet tube. In some embodiments, securing an attachment member includes threading the attachment member onto the stylet tube. 
     The method  500  may also include inserting the stylet into a central lumen of a catheter (block  520 ). The catheter may include a peripherally inserted central catheter having more than one extension leg, where each extension includes an extension leg lumen in fluid communication with the central lumen. 
     Inserting the stylet into the central lumen of the catheter may also include positioning the stylet with respect to the catheter (block  521 ) such that the distal end of the stylet tube is disposed adjacent a distal end of the catheter. 
     Inserting the stylet into the central lumen of the catheter may also include coupling the attachment member to a connector of the catheter (block  522 ). 
     While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.