Catheter Insertion System

Abstract

The catheter assembly (100) includes a multi-lumen catheter (102), a primary stylet (120), and a secondary stylet (140). The primary and secondary stylets are each inserted into separate lumens (108A, 108B) extending along the catheter tube (106). The primary stylet includes a magnetic region (226) that allows for magnetic tracking. The secondary stylet is configured to prevent buckling of the magnetic region during insertion. The secondary stylet includes a proximal section (242) having a proximal column strength and a distal section having a distal column strength greater than the proximal column strength. During use, an insertion force that exceeds an insertion force limit buckles the proximal section to prevent buckling of the distal section. The primary stylet may also include an electrical sensor and / or optical fiber configured for shape sensing.

Description

[Technical field]

[0001] The present disclosure relates to a catheter insertion system. [Background technology]

[0002] Inserting a peripherally inserted central catheter ("PICC") into a patient's vasculature may include placing a stylet within the lumen of the PICC to stabilize the PICC during insertion of the PICC-stylet assembly. However, the tip of the PICC may encounter an obstacle during placement, leading to a buckling or bending event of the stylet and the tip of the PICC. A bending event may lead to breakage of the tip of the stylet, and one or more tip breaks may be considered a serious failure of the PICC and may lead to adverse patient outcomes. Having a catheter insertion system that is not prone to bending events would be beneficial to patients and clinicians, allowing clinicians to properly place a PICC without fear of failure of the PICC or stylet. Disclosed herein are catheter assemblies, systems, and methods of use that address the above problems. Summary of the Invention

[0003] A catheter assembly disclosed herein, according to some embodiments, includes a multi-lumen catheter having a first extension leg in fluid communication with a first lumen and a second extension leg in fluid communication with a second lumen. A primary stylet is inserted into the first lumen, the primary stylet including a magnetic region configured to enable a medical tracking system to track the primary stylet during advancement of the catheter along the patient's vasculature, and a secondary stylet is inserted into the second lumen. A distal section of the secondary stylet is configured to inhibit buckling of the magnetic region of the primary stylet during advancement of the catheter assembly along the patient's vasculature.

[0004] In some embodiments, the distal section defines a distal column strength that is greater than the column strength of the magnetic region of the primary stylet, and in some embodiments, the distal section extends along the magnetic region.

[0005] In some embodiments, the proximal section of the secondary stylet defines a proximal column strength, the proximal column strength being less than the distal column strength. In some embodiments, the diameter of the proximal section is less than the diameter of the distal section, and in some embodiments, the secondary stylet defines a transition section extending between the proximal and distal sections, the transition section defining a diameter between a distal diameter and a proximal diameter. In some embodiments, the transition section defines a taper extending along the transition section, the taper defining a proximal diameter at a proximal end of the transition section and a distal diameter at a distal end of the transition section.

[0006] In some embodiments, the proximal section extends proximally beyond the second extension leg such that the proximal section is configured to receive a catheter insertion force applied to the proximal section by a clinician.

[0007] In some embodiments, the proximal column strength defines an insertion force limit for the catheter when an insertion force is applied to the secondary stylet, and in some embodiments, the proximal section is configured to buckle when the insertion force exceeds the insertion force limit, hi some embodiments, the insertion force limit is configured to prevent buckling of the magnetic region.

[0008] In some embodiments, the primary stylet includes a sheath extending along with a magnetic region, the magnetic region including one or more magnets disposed within the sheath. In some embodiments, the primary stylet includes one or more sensors configured to detect one or more electrical signals. In some embodiments, the one or more sensors include electrodes configured to detect ECG signals such that a medical tracking system can verify the position of the catheter within the vasculature. In some embodiments, the primary stylet includes an optical fiber extending along the primary stylet, the optical fiber configured to enable shape sensing of the primary stylet by the medical tracking system.

[0009] In some embodiments, the secondary stylet includes at least one of a magnetic region, one or more electrical sensors, or an optical fiber. In some embodiments, the primary stylet includes a primary stylet mounting device configured to selectively couple the primary stylet to the first extension leg such that longitudinal displacement of the primary stylet relative to the catheter is inhibited. In some embodiments, the secondary stylet includes a secondary stylet mounting device configured to selectively couple the secondary stylet to the second extension leg such that longitudinal displacement of the secondary stylet relative to the catheter is inhibited.

[0010] Also disclosed herein is a method for positioning a catheter within a patient's vasculature, according to some embodiments, comprising providing a catheter assembly including a multi-lumen catheter having a first extension leg in fluid communication with a first lumen and a second extension leg in fluid communication with a second lumen. The catheter assembly further includes a primary stylet inserted within the first lumen, the primary stylet including a magnetic region configured to enable a medical tracking system to track the primary stylet during advancement of the catheter along the patient's vasculature. The catheter assembly further includes a secondary stylet inserted within the second lumen, the secondary stylet defining a proximal section extending proximally beyond the second extension leg. The method further includes applying an insertion force to the proximal section to advance the catheter along the vasculature.

[0011] In some embodiments of the method, the secondary stylet defines a distal section having a distal column strength greater than a column strength of the magnetic region of the primary stylet, hi some embodiments of the method, the proximal section includes a proximal column strength less than the distal column strength.

[0012] In some embodiments of the method, providing a catheter assembly includes (i) inserting a primary stylet into the first lumen; and (ii) inserting a secondary stylet into the second lumen such that a distal section is positioned adjacent to the magnetic region.

[0013] In some embodiments of the method, the proximal column strength defines an insertion force limit for the catheter such that the proximal section is configured to buckle when an insertion force applied by a clinician exceeds the insertion force limit, hi some embodiments of the method, the insertion force limit prevents buckling of the magnetic region.

[0014] In some embodiments, the method further includes coupling a primary stylet mounting device between the primary stylet and the first extension leg of the catheter to inhibit longitudinal displacement of the primary stylet relative to the catheter. In some embodiments, the method further includes coupling a secondary stylet mounting device between the secondary stylet and the second extension leg of the catheter to inhibit longitudinal displacement of the secondary stylet relative to the catheter.

[0015] These and other features of the concepts provided herein will become more apparent to those of ordinary skill in the art in view of the accompanying drawings and following description, which describe in more detail certain embodiments of such concepts.

[0016] A more detailed description of the present disclosure will now be given with reference to certain embodiments illustrated in the accompanying drawings. It will be understood that these drawings represent only typical embodiments of the present invention and therefore should not be considered limiting of its scope. Exemplary embodiments of the present invention will be described and explained with additional features and details using the following accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows a perspective view of a catheter insertion system, according to some embodiments. [Figure 2A-2B] 1 shows a top view of several components of a catheter insertion system, including a primary stylet and a secondary stylet. [Figure 2C] 1 illustrates a cross-sectional view of a primary stylet and a secondary stylet disposed within a catheter, according to some embodiments. [Figure 3A-3C] 2A-2C show various views of the system of FIG. 1 depicting an exemplary method of inserting a catheter, according to some embodiments. [Figure 3D-3E] 2 shows a diagram of the system of FIG. 1 inserted into a blood vessel having an obstruction therein, according to some embodiments. [Figure 4] 1 shows a flowchart of an exemplary method of placing a catheter, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Before some specific embodiments are disclosed in more detail, it should be understood that the specific embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that the specific embodiments disclosed herein may have features that can be easily separated from the specific embodiment and can be combined or substituted in any way with any of the other several embodiments disclosed herein.

[0019] With respect to the terms used herein, it should also be understood that the terms are intended to describe certain particular embodiments, and that 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 within a group of features or steps, and do not provide sequentiality or numerical limitations. For example, the "first," "second," and "third" features or steps need not appear in that order, nor need a particular embodiment that includes such features or steps be limited to those three features or steps. Designations such as "left," "right," "top," "bottom," "front," "rear," and similar terms are used for convenience and are not intended to imply, for example, a particular fixed position, orientation, direction, etc. Rather, such designations are used to reflect, for example, a relative position, orientation, direction, etc. The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0020] For example, references to the "proximal," "proximal portion," or "proximal end" of a catheter disclosed herein include the portion of the catheter that is intended to be located near the clinician when the catheter is used on a patient. Similarly, for example, the "proximal length" of a catheter includes the length of the catheter that is intended to be located near the clinician when the catheter is used on a patient. For example, the "proximal end" of a catheter includes the end of the catheter that is intended to be located near the clinician when the catheter is used on a patient. The proximal portion, end, or length of a catheter may include the proximal end of the catheter. However, the proximal portion, end, or length of a catheter need not include the proximal end of the catheter. That is, unless the context suggests otherwise, the proximal portion, end, or length of a catheter is not the terminal portion, or length of the catheter.

[0021] For example, references to the "distal," "distal portion," or "distal end" of a catheter disclosed herein include the portion of the catheter that is intended to be located near or within the patient when the catheter is used on a patient. Similarly, for example, the "distal length" of a catheter includes the length of the catheter that is intended to be located near or within the patient when the catheter is used on a patient. For example, the "distal end" of a catheter includes the end of the catheter that is intended to be located near or within the patient when the catheter is used on a patient. The distal portion, end, or length of a catheter may include the distal end of the catheter. However, the distal portion, end, or length of a catheter need not include the distal end of the catheter. That is, unless the context suggests otherwise, the distal portion, end, or length of a catheter is not the terminal portion, or length of the catheter.

[0022] Unless defined otherwise, all technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0023] Any method disclosed herein includes one or more steps or actions for carrying out the described method. Method steps and / or actions may be interchangeable 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. Furthermore, only subroutines or portions of the methods described herein may be separate methods within the scope of the present disclosure. In other words, some methods may include only a portion of the steps described in a more detailed method. In addition, all embodiments disclosed herein are combinable and / or interchangeable unless otherwise stated or unless such combination or interchange is contrary to the described operability of any embodiment.

[0024] Throughout this specification, references to approximations may be made, such as by use of the term "substantially." For each such reference, it should be understood that in some embodiments, the value, feature, or characteristic may be specified without the approximation. For example, when modifiers such as "about" and "substantially" are used, these terms include within their scope the modified terms without those modifiers. For example, when the term "substantially linear" is described with respect to a feature, it is understood that in further embodiments, the feature may have a strictly linear configuration.

[0025] FIG. 1 shows a perspective view of a catheter insertion system (or catheter assembly) 100, according to some embodiments. The catheter insertion system ("system") 100 includes a multi-lumen catheter 102, e.g., a peripherally inserted central catheter ("PICC"). The catheter 102 includes a hub 104 distally coupled to a catheter tube 106. The catheter tube 106 includes a first lumen 108A and a second lumen 108B extending along the catheter tube 106 between the hub 104 and a distal opening 109 at a distal end 107 of the catheter tube 106. The catheter 102 includes a first extension leg 110A and a second extension leg 110B coupled to the hub 104. The first extension leg 110A includes a first extension leg lumen 112A in fluid communication with the first lumen 108A, and the second extension leg 110B includes a second extension leg lumen 112B in fluid communication with the second lumen 108B. For ease of explanation, embodiments of the system 100 are described with respect to a dual lumen catheter. However, it should be understood that in some embodiments, the system 100 may be designed to include a catheter having three or more lumens that are considered to be within the scope of the present invention.

[0026] The system 100 further includes a primary stylet 120 and a secondary stylet 140. The primary stylet 120 and the secondary stylet 140 are inserted into the catheter 102. More specifically, the primary stylet 120 is inserted into the first extension leg lumen 112A and the first lumen 108A. Similarly, the secondary stylet 140 is inserted into the second extension leg lumen 112B and the second lumen 108B. In some embodiments, the catheter 102 may be provided with one or both of the primary stylet 120 and the secondary stylet 140 pre-inserted. In other embodiments, a clinician may insert either or both of the primary stylet 120 and the secondary stylet 140 at the time of or during placement of the catheter 102 within the patient's vasculature.

[0027] In some cases, the catheter may encounter resistance when advancing the catheter along the vasculature. For example, the distal tip of the catheter may abut an obstacle (e.g., a blood vessel wall) during advancement. In such cases, the catheter (e.g., the distal end portion) may buckle, and in some cases, the buckling may cause damage to the primary stylet 120 and / or the catheter 102. As a further example, the catheter 102 with the primary stylet 120 inserted therein may abut an obstacle during advancement, causing the distal end portion of the catheter 102 and the primary stylet 120 to buckle. In some cases, the buckling of the primary stylet 120 may cause damage to the primary stylet 120. The secondary stylet 140 is generally configured to inhibit / prevent buckling of the primary stylet 120 in such cases. In some cases, the buckling of the primary stylet 120 may break the distal portion of the primary stylet 120, causing the primary stylet 120 to fail. Thus, when the secondary stylet 140 is inserted and utilized during advancement of the catheter 102, it may protect the primary stylet 120 from loss of functionality.

[0028] 2A shows a plan view of a primary stylet 120, according to some embodiments. The primary stylet 120 defines a proximal end 222 and a distal end 224. In the illustrated embodiment, the distal end 224 may include a magnetic portion 226 having one or more magnets 228 configured to generate one or more magnetic fields that are detected in three-dimensional space by a medical device tracking system. U.S. Patent Application Publication No. 2013-0060116, entitled "INTEGRATED SYSTEM FOR INTRAVASCULAR PLACEMENT OF A CATHETER," which illustrates and describes a stylet configured for magnetic tracking and a magnetic tracking system, is incorporated herein by reference in its entirety. In the illustrated embodiment, the magnetic portion 226 may include a sheath (or tubing) 230 extending along the magnetic region 226, and the one or more magnets 228 may be disposed within the sheath 230. In some embodiments, the sheath 230 may include polyimide tubing, PVC, silicone, or the like. In some embodiments, the magnetic portion 226 may define a weak resistance to buckling.

[0029] Further, in the illustrated embodiment, the distal end 224 of the primary stylet 120 may include one or more sensors 232 (e.g., electrodes) configured to detect one or more electrical signals (e.g., ECG signals) during placement of the catheter 102. U.S. Patent No. 9,220,432, entitled "METHOD AND SYSTEM OF UTILIZING ECG SIGNAL FOR CENTRAL VENOUS CATHETER TIP POSITIONING," which illustrates and describes a stylet having electrical sensors for detecting ECG signals and a medical system for monitoring ECG signals, is hereby incorporated by reference in its entirety.

[0030] In some embodiments, the primary stylet 120 may include an optical fiber 236 extending along at least a portion of the primary stylet 120. The optical fiber 236 may be configured for shape sensing as taught by U.S. Patent Application Publication No. 2022-0034733, entitled "BRAGG GRATED FIBER OPTIC FLUCTUATION SENSING AND MONITORING SYSTEM," which illustrates and describes optical fibers and optical fiber shape sensing systems for shape sensing, and which is incorporated herein by reference in its entirety. In summary, the primary stylet 120 is generally configured for tracking and / or placement confirmation during use. Thus, the primary stylet 220 may include all or any subset of the magnetic region 226, one or more sensors 232, or optical fiber 236.

[0031] The primary stylet 120 defines a primary stylet diameter 224 extending between the proximal end 222 and the distal end 224 of the primary stylet 120. In the illustrated embodiment, the primary stylet diameter 224 is constant (i.e., the same) between the proximal end 222 and the distal end 224. In other embodiments, the primary stylet 120 may be tapered from the proximal end 222 to the distal end 224, having a larger stylet diameter 224 at the proximal end 222 and a smaller stylet diameter 224 at the proximal end 222, or vice versa. In some embodiments, the primary stylet 120 may include a primary stylet attachment device 223 configured to selectively couple the primary stylet 120 to the first extension leg 112A such that longitudinal displacement of the primary stylet 120 relative to the catheter 102 is prevented. In some embodiments, the primary stylet attachment device 223 may include a luer lock feature configured to mate with a luer connection hub of the first extension leg 112A.

[0032] 2B shows a plan view of the secondary stylet 140, according to some embodiments. As discussed above, the secondary stylet 140 is generally configured to inhibit / prevent buckling of the primary stylet 120 and / or the catheter 102 during advancement of the catheter 102. More specifically, the secondary stylet 140 may be configured to inhibit / prevent buckling of the primary stylet 120 along the magnetic portion 226.

[0033] The secondary stylet 140 extends between a proximal end 242 and a distal end 243. Similar to the primary stylet 120, the secondary stylet 140 may include a secondary stylet attachment device 248 configured to selectively couple the secondary stylet 140 to the second extension leg 112B such that longitudinal displacement of the secondary stylet 140 relative to the catheter 102 is prevented. In some embodiments, the secondary stylet attachment device 248 may include a luer lock feature configured to couple with a luer connection hub of the second extension leg 112B. Additionally, in some embodiments, although not shown, the secondary stylet 140 may include one or more of a magnetic region 226, one or more sensors 232, or an optical fiber 236 in addition to or in place of the primary stylet 120.

[0034] The secondary stylet 140 also defines a column strength (i.e., resistance to buckling) along the length of the secondary stylet 140, and the column strength may vary along the length of the secondary stylet 140. In the illustrated embodiment, the varying column strength of the secondary stylet 140 is defined by the varying diameter of the secondary stylet 140 along the length of the secondary stylet 140. In other embodiments, the varying column strength may be defined solely by the varying properties of the secondary stylet material or in combination with the varying diameter of the secondary stylet 140. Thus, in other embodiments, the diameter of the secondary stylet diameter 246 may be constant along its length.

[0035] The secondary stylet 140 may include (i) one or more tapered portions defining a change in diameter and (ii) one or more non-tapered portions defining a substantially constant diameter. In the illustrated embodiment, the secondary stylet 140 defines a proximal section 244, a distal section 245, and a transition section 246 disposed between the proximal section 244 and the distal section 245. The proximal section 244 may include a proximal diameter 244A, which is substantially constant. The distal section 245 may include a distal diameter 245A, which is substantially constant. The transition section 246 is configured to transition the proximal diameter 244A to the distal diameter 244A. Thus, the transition section 246 defines a diameter between the proximal diameter 244A and the distal diameter 244A. In the illustrated embodiment, the transition section 246 includes a taper to transition the proximal diameter 244A to the distal diameter 245A. The distal diameter 245A is larger than the proximal diameter 244A.

[0036] In the illustrated embodiment, the proximal diameter 244A and the distal diameter 245A are configured to cooperate to prevent buckling of the distal section 245 (and, associated therewith, the magnetic portion 226 of the primary stylet 120) during the event of abutment as described above. The distal diameter 245A is configured to resist buckling when a longitudinal force along the distal section 245, as may be defined by a catheter insertion force, falls below a distal column strength of the distal section 245 during use. Thus, the distal column strength of the distal section 245 may define a catheter insertion force limit.

[0037] The proximal diameter 244A may be configured to prevent longitudinal forces from exceeding the distal column strength during use. More specifically, the proximal diameter 244A is configured to limit the longitudinal forces that may be applied to the secondary stylet 140. The proximal diameter 244A defines the proximal column strength of the proximal section 244. Thus, the proximal diameter 244A may be configured to allow an outer portion of the proximal section 244 (i.e., the portion of the proximal section 244 that is outside the second extension leg lumen 112B) to buckle when longitudinal forces applied to the secondary stylet 140 exceed the proximal column strength, as described further below. In summary, the proximal column strength is less than the distal column strength such that catheter insertion forces applied to the secondary stylet 140 will buckle the proximal section 244, thereby preventing buckling of the distal section 245.

[0038] In some embodiments, the proximal ends 222, 242 may be constructed from a different material than the distal ends 224, 244. For example, the distal ends 224, 244 may be constructed from a first material and the proximal sections 222, 242 may be constructed from a second material, where the first material is more rigid than the second material. In some embodiments, the entire primary stylet 120 may be formed from a substantially rigid material. Conversely, a portion of the primary stylet 120 may be formed from a rigid material and another portion of the primary stylet 120 may be formed from a substantially flexible material. For example, the proximal end 222 may be formed from a more rigid material than the distal end 224. Similarly, in some embodiments, the entire secondary stylet 140 may be formed from a substantially rigid material, or a portion of the secondary stylet 140 may be formed from a rigid material and another portion of the secondary stylet 140 may be formed from a substantially flexible material. For example, the distal end 244 may be formed of a stiffer material than the proximal end 242 .

[0039] 2C illustrates a cross-sectional view of a catheter tube 106 including a primary stylet 120 disposed within a first lumen 108A and a secondary stylet 140 disposed within a second lumen 108B, according to some embodiments. In some embodiments, the primary stylet 120 and / or secondary stylet 140 may be positioned along the catheter tube 106 such that the distal ends 224, 244 of the primary stylet 120 and secondary stylet 140, respectively, are disposed adjacent the distal end 107 of the catheter tube 106.

[0040] As shown, the distal section 245 of the secondary stylet 140 extends alongside the magnetic portion 226 of the primary stylet 120. In the illustrated embodiment, the length of the distal section 245 may be the same as or longer than the length of the magnetic portion 226. The transition section 246, or a portion thereof, may be disposed within the second lumen 108B. In some embodiments, a portion of the proximal section 244 may also be disposed within the second lumen 108B.

[0041] In some embodiments, the secondary stylet 140 may be optimized such that a single configuration of the secondary stylet 140 may be utilized for a variety of different catheter sizes and / or configurations. Thus, optimizing the secondary stylet 140 for a variety of different catheter configurations may standardize the feel and force required to accurately place the catheter 102 and prevent buckling regardless of catheter size. In some embodiments, optimizing the secondary stylet 140 for all catheter configurations will eliminate variations required in insertion technique for a variety of different sized catheters 102. In other embodiments, the primary stylet 120 may be consistent (e.g., in size and shape) and multiple secondary stylet 140 configurations may be provided to accommodate different catheter configurations.

[0042] 3A-3C show various perspective views of the system 100 according to an exemplary method of inserting the catheter 102. FIG. 3A shows an exposed view of the system 100. FIG. 3B shows the system 100 with the primary stylet 120 and secondary stylet 140 partially disposed within the catheter 102, and FIG. 3C shows the system 100 with the primary stylet 120 and secondary stylet 140 fully inserted within the catheter 102. In some embodiments, the catheter 102 may be prepared for insertion into the vasculature. As shown in FIG. 3A, the catheter insertion system 100 includes a secondary stylet 140 and a primary stylet 120 having one or more sensors 232 and one or more magnets 228 configured to detect electrical signals. As shown in FIG. 3B, in some embodiments, the primary stylet 120 may be inserted into the first extension leg 110A. In some embodiments, the proximal end 222 of the primary stylet 120 may be selectively coupled to the proximal end of the catheter 102 to fix the position of the primary stylet 120 within the catheter 102. In some embodiments, the secondary stylet 140 may be inserted into the second extension leg 110B. In some embodiments, the proximal end 242 of the secondary stylet 140 may be selectively coupled to the proximal end of the catheter 102 to fix the position of the secondary stylet 140 within the catheter 102. In some embodiments, the primary stylet 120 or the secondary stylet 140 may be fully inserted into the catheter 102 before the other of the primary stylet 120 or the secondary stylet 140 is inserted into the catheter 102. In some embodiments, the primary stylet 120 and the secondary stylet 140 may be inserted into the catheter 102 simultaneously, as shown in FIG. 3B.

[0043] In some embodiments, the primary stylet attachment device 223 of the primary stylet 120 may be coupled between the primary stylet 120 and the first extension leg 110A. Similarly, the secondary stylet attachment device 248 of the secondary stylet 140 may be coupled between the secondary stylet 140 and the second extension leg 110B. With the primary stylet 120 and the secondary stylet 140 disposed within the catheter 102, the catheter 102 may be inserted into the patient's vasculature. In some embodiments, a medical device tracking system (not shown) may be utilized to detect and track one or more magnets 228 on the primary stylet 120. Similarly, the medical device tracking system may be utilized to confirm the position of the sensor 232 within the vasculature. Once the catheter 102 is disposed within the patient's vasculature, the primary stylet 120 and the secondary stylet 140 may be removed from the catheter 102.

[0044] 3D-3E show the system 100 during advancement of the catheter 102 along a vasculature where an obstacle is present within the vasculature, according to some embodiments. FIG. 3D shows the clinician advancing the catheter 102 before the distal end 107 of the catheter 102 contacts the obstacle 330, and FIG. 3E shows the clinician applying a longitudinal force to the secondary stylet 140 after the distal end 107 of the catheter 102 contacts (abuts) the obstacle 330. As shown in FIG. 3D, in some embodiments, the clinician 310 may grasp the secondary stylet 140 and apply a longitudinal force 315 to the proximal section 244 of the secondary stylet 140 to advance the catheter 102 along a blood vessel 320. As further shown in FIG. 3D, the proximal section 244 includes sufficient column strength to resist buckling of the proximal section 244 when a longitudinal force 315 is applied to advance the catheter 102 in the absence of an obstacle.

[0045] 3E illustrates a case where the distal end 107 of the catheter 102 abuts an obstruction 330, halting the advancement of the catheter 102. The clinician applies a longitudinal force 316 greater than the longitudinal force 315 of FIG. 3D to continue advancing the catheter 102. When the longitudinal force 316 exceeds the column strength of the proximal section 244, a buckle 317 of the proximal section 244 occurs between the clinician 310 and the extension leg 110B. The buckle 317 thus prevents a longitudinal force greater than the longitudinal force 316 from being applied to the catheter 102 and the secondary stylet 140, including the primary stylet 120. In summary, because the column strength of the distal section 245 is greater than the column strength of the proximal section 244 , the buckling 317 of the proximal section 244 prevents buckling of the distal section 245 , thereby protecting the magnetic portion 226 of the primary stylet 120 .

[0046] 4 shows a flowchart of an exemplary method 400 of positioning a catheter 102 in a patient's vasculature using the catheter insertion system 100, according to some embodiments. In some embodiments, the method 400 may include inserting a primary stylet 120 into the catheter 102 (block 402). In some embodiments, the catheter 102 includes a hub 104 distally coupled to a catheter tube 106 having a first lumen 108A and a second lumen 108B therein. The hub 104 may be proximally coupled to two or more extension legs 110A / 110B, each extension leg 110A / 110B in fluid communication with one lumen 108A / 108B. In some embodiments, inserting the primary stylet 120 into the catheter 102 includes slidably inserting the primary stylet 120 into the first lumen 108A. In some embodiments, the primary stylet 120 includes a magnetic region 226 and one or more sensors 232. In some embodiments, the primary stylet 120 may have a constant primary stylet diameter 224 from the proximal end 222 to the distal end 224. In some embodiments, inserting the primary stylet 120 into the catheter 102 includes coupling a primary stylet attachment device 223 of the primary stylet 120 to the extension leg 110A.

[0047] The method 400 further includes inserting the secondary stylet 140 into the catheter 102 (block 404). In some embodiments, inserting the secondary stylet 140 into the catheter 102 includes slidably inserting the secondary stylet 140 into the second lumen 108B. In some embodiments, the secondary stylet 140 includes a proximal stylet diameter 244A that is smaller than a distal stylet diameter 245A. In some embodiments, inserting the secondary stylet 140 into the catheter 102 includes coupling a secondary stylet attachment device 248 of the secondary stylet 140 to the extension leg 110B.

[0048] The method 400 further includes placing the catheter 102 in the vasculature (block 406). In some embodiments, placing the catheter 102 in the vasculature includes placing the catheter 102 in the vasculature with the primary stylet 120 and the secondary stylet 140 slidably inserted into the catheter 102. In some embodiments, placing the catheter 102 includes slidably inserting the catheter 102 into the patient's vasculature. In some embodiments, placing the catheter 102 includes grasping the secondary stylet 140 and applying a catheter insertion force to the secondary stylet 140 to insert the catheter 102. In some embodiments, placing the catheter 102 includes applying a first catheter insertion force to the secondary stylet 140 and applying a second catheter insertion force to the secondary stylet 140, the second catheter insertion force being greater than the first catheter insertion force. In such embodiments, the proximal section 244 resists buckling when a first catheter insertion force is applied, and the proximal section 244 buckles when a second catheter insertion force is applied.

[0049] The method 400 further includes tracking the position of the catheter 102 in three-dimensional space (block 408) to confirm proper placement of the catheter 102. In some embodiments, tracking the position of the catheter 102 in three-dimensional space includes tracking the position of the one or more magnets 228 along the vasculature by a medical device tracking system. In some embodiments, tracking the position of the catheter 102 includes confirming the position of the one or more sensors 232 by a medical device tracking system that detects one or more electrical signals within the body. In some embodiments, once the position of the catheter 102 has been confirmed, the primary stylet 120 and the secondary stylet 140 may be removed from the catheter 102.

[0050] Although some specific embodiments are disclosed herein, and the specific embodiments are disclosed in some detail, the specific embodiments are not intended to limit the scope of the concepts provided herein. Additional improvements and / or modifications may be apparent to those skilled in the art, and the broader aspects encompass these improvements and / or modifications as well. Thus, one may depart from the specific embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claims

1. 1. A catheter assembly comprising: a multi-lumen catheter having a first extension leg in fluid communication with the first lumen and a second extension leg in fluid communication with the second lumen; a primary stylet inserted into the first lumen, the primary stylet including a magnetic region configured to enable a medical tracking system to track the primary stylet during advancement of the catheter along a patient's vasculature; a secondary stylet inserted into the second lumen; A catheter assembly, wherein the distal section of the secondary stylet is configured to prevent buckling of the magnetic region during advancement of the catheter assembly along a patient's vasculature.

2. The assembly of claim 1 , wherein the distal section defines a distal column strength greater than a column strength of the magnetic region of the primary stylet.

3. The assembly of claim 1 , wherein the distal section extends along the magnetic region.

4. The assembly of claim 2 , wherein the proximal section of the secondary stylet defines a proximal column strength, the proximal column strength being less than the distal column strength.

5. the proximal section defines a proximal diameter; the distal section defines a distal diameter; The assembly of claim 4 , wherein the proximal diameter is smaller than the distal diameter.

6. the secondary stylet defines a transition section extending between the proximal section and the distal section; The assembly of claim 5 , wherein the transition section defines a diameter between the distal diameter and the proximal diameter.

7. the transition section defines a taper extending along the transition section; The taper is the proximal diameter at the proximal end of the transition section; The assembly of claim 6 , defining a distal diameter at a distal end of the transition section.

8. The assembly of claim 4 , wherein the proximal section extends proximally beyond the second extension leg so as to be configured to receive a catheter insertion force applied to the proximal section by a clinician.

9. The assembly of claim 8 , wherein the proximal column strength defines an insertion force limit for the catheter when the catheter insertion force is applied to the secondary stylet.

10. The assembly of claim 9 , wherein the proximal section is configured to buckle when the catheter insertion force exceeds the insertion force limit.

11. The assembly of claim 9 , wherein the insertion force limit is configured to prevent buckling of the magnetic region.

12. the primary stylet includes a sheath extending along the magnetic region; The assembly of claim 1 , wherein the magnetic region includes one or more magnets disposed within the sheath.

13. The assembly of claim 1 , wherein the primary stylet includes one or more sensors configured to detect one or more electrical signals.

14. 14. The assembly of claim 13, wherein the one or more sensors include electrodes configured to detect ECG signals so that the medical tracking system can ascertain the position of the catheter within the vasculature.

15. 10. The assembly of claim 1, wherein the primary stylet includes an optical fiber extending along the primary stylet, the optical fiber configured to enable shape sensing of the primary stylet by the medical tracking system.

16. 10. The assembly of claim 1, wherein the secondary stylet includes at least one of the magnetic region, one or more sensors configured to detect one or more electrical signals, or optical fibers configured to enable shape sensing of the primary stylet by the medical tracking system.

17. 10. The assembly of claim 1, wherein the primary stylet includes a primary stylet attachment device configured to selectively couple the primary stylet to the first extension leg such that longitudinal displacement of the primary stylet relative to the catheter is prevented.

18. 18. The assembly of claim 1, wherein the secondary stylet includes a secondary stylet attachment device configured to selectively couple the secondary stylet to the second extension leg such that longitudinal displacement of the secondary stylet relative to the catheter is prevented.

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