A new passive detachable introducer sheath

Abstract

The utility model relates to a novel blunt separation intubation sheath, including inner sheath and the outer sheath of close packing in the outer surface of inner sheath, and the inner sheath is hollow and is like a thorn in the tip, and the inner sheath still includes inner sheath handheld end, inner sheath base and inner sheath lead-in end, after packing, the inner surface of outer sheath is close to the outer surface of inner sheath, and also is hollow and is like a thorn, and the outer sheath still includes outer sheath base, outer sheath and stays end, and the top of outer sheath and stays end is opened and is convenient for the inner sheath lead-in end to stretch out from the opening of outer sheath and stays end, and its characterized in that, the length difference of inner sheath base to the top of thorn lead-in end and outer sheath base to outer sheath and stays end length is 4 4.5cm.

Description

Technical Field

[0001] This utility model relates to a vascular indwelling needle technology, specifically a novel blunt dissection catheter sheath. Background Technology

[0002] Ultrasound-guided placement of peripherally inserted central catheters (PICCs) using the modified Selginger technique (MST) can improve the success rate of PICC placement. However, the surgical procedure involves dilating the skin with a scalpel, which can damage the dermis. If blood vessels, lymphatic vessels, and nerves in the dermis are damaged, bleeding or effusion may occur at the puncture site.

[0003] Blunt dissection is a commonly used method for skin dilation. It abandons the scalpel method and uses a dilator to locally dilate the puncture site. The dilator and outer sheath are then combined and inserted into the blood vessel. This can effectively reduce the occurrence of puncture site leakage and reduce the pain of skin dilation after catheter placement.

[0004] The most advanced blunt dissection method currently available is the modified blunt dissection method, which typically uses the outer cannula of a 14G PICC puncture needle assembled with the inner sheath of a micro-cannula (see Existing Technology / Paper in the instruction manual) to advance the blood vessel in one go. The outer cannula of the 14G PICC puncture needle is soft, resulting in low frictional resistance to the blood vessel during insertion and minimizing damage to the blood vessel.

[0005] The existing 14G PICC puncture needle, also known as a blind puncture needle, is designed for non-ultrasound-guided catheter placement. The depth of the blood vessels is limited to superficial vessels that are visible to the naked eye. However, ultrasound-guided puncture involves deep vessels that are not visible to the naked eye, sometimes reaching a depth of more than 3 cm. This makes the outer cannula of this puncture needle too short (see below for specific dimensions), which cannot meet the needs of these patients.

[0006] Extensive clinical data indicates that approximately 10-15% of PICC placement patients are obese, have edema, or have lower limb deformities, with arm or leg circumferences exceeding 30cm, sometimes even reaching around 50cm. Their vessel depth is typically 2-3cm or more. The modified blunt dissection method (using the commonly used 14G PICC needle) has an inner sheath length of 7cm (corresponding to the inner sheath of the 4.5F intubation sheath kit) and an outer sheath length of 3.2cm. Clinically, the sheath is inserted at an acute angle to the skin, not a right angle. Therefore, after the 3.2cm outer sheath enters the skin, a portion is removed from the subcutaneous oblique insertion point above the vessel. This limitation only meets the needs of patients with vessel depths of 2cm or less, and cannot meet the needs of patients with vessel depths greater than 2cm.

[0007] Therefore, how to solve the above problems is an important research topic for those skilled in the art. Utility Model Content

[0008] To overcome the shortcomings of the prior art, the present invention aims to provide a method for placing catheters in blood vessels deeper than 2 cm under the skin, while also being able to place catheters in blood vessels with a depth of less than 2 cm.

[0009] A novel blunt dissection cannula includes an inner sheath and an outer sheath tightly fitted over the inner sheath. The inner sheath is slender, hollow, and spiky, and also includes a handle, a base, and an insertion end. After fitting, the inner surface of the outer sheath adheres tightly to the outer surface of the inner sheath and is also hollow and spiky. The outer sheath also includes a base and an indwelling end. An opening is located at the top of the indwelling end to facilitate the insertion end of the inner sheath extending from the opening at the indwelling end. The difference between the length from the inner sheath base to the tip of the needle-like insertion end and the length from the outer sheath base to the indwelling end of the outer sheath is 4-4.5 cm (4.5 cm was used in the experiment, but based on the derivation below and experience during specific experiments, the inventor believes that theoretically, a certain technical effect can be achieved within 4-4.5 cm). The characteristic of this patent is that the length from the inner sheath base to the tip of the needle-like insertion end is greater than the length from the sheath piercing the skin to the blood vessel, and it requires the inner sheath to enter the blood vessel first, followed by the outer sheath. Typically, the blood vessel depth (at a 90° angle with the skin) is 0.5-3 cm (deeper cases are also possible), and the vascular sheath puncture angle is usually 10-60°. Based on the vascular sheath distance for a 3 cm deep blood vessel, the inner sheath is at least 4-4.5 cm longer than the outer sheath. These data are derived from clinical experience.

[0010] Furthermore, the length from the inner sheath base to the top of the spiky insertion end is 9.5-10.5 cm, and the length from the outer sheath base to the outer sheath indwelling end is 5-6 cm. These data are optimal values ​​obtained from experiments.

[0011] Furthermore, the length from the inner sheath base to the top of the spiky insertion end is 10 cm, and the length from the outer sheath base to the outer sheath indwelling end is 5.5 cm. These data are the optimal values ​​obtained from experiments.

[0012] Furthermore, the outer diameter of the top of the inner sheath inlet is 0.8 mm, and the outer diameter of the bottom of the inner sheath inlet is 1.7 mm; the inner diameter of the top opening of the outer sheath retention end is 1.6 mm, and the inner diameter of the bottom of the outer sheath retention end is 1.78 mm. These dimensions facilitate a tight fit between the inner and outer sheaths after assembly.

[0013] Furthermore, the outer diameter of the opening at the top of the indwelling end of the outer sheath is 1.9 mm, and the outer diameter of the bottom of the indwelling end of the outer sheath is 2.3 mm. These dimensions facilitate the smooth penetration of the outer sheath through the skin and into the blood vessel, without causing puncture-related side effects (see the clinical trial in the specific embodiment for details).

[0014] The new microcatheter sheath has an inner sheath length (the length from the bottom of the inner sheath base to the top of the spiky insertion end, the same below) of 10cm and an outer sheath length (the length from the bottom of the outer sheath base to the indwelling end of the outer sheath, the same below) of 5.5cm. The inner sheath is 4.5cm longer than the outer sheath, which is longer than the inner sheath of the traditional 14G PICC puncture needle (the above data for the traditional 14G PICC puncture needle are 7cm and 3.2cm, respectively), thus better meeting the needs of patients with a vascular depth greater than 2cm for catheter placement.

[0015] Existing technology 1: Currently, the PICC catheters widely used in clinical practice are single-lumen 4F and high-pressure resistant double-lumen 5F specifications, in which the puncture needle (the puncture needle is an accessory of the catheter) is 21G (the outer diameter of the needle tip is 0.8mm) and the length is 7cm.

[0016] The 4F catheter has a 4.5F sheath, with an inner sheath length of 7cm and an outer sheath length of 5cm. In the modified blunt dissection method, the commonly used outer sheath length is 3.2cm, and the 5F catheter has a 5F sheath, with an inner sheath length of 10cm and an outer sheath length of 7cm.

[0017] Prior Art 2: Another patent (a PICC catheter placement minimally invasive retractor sheath assembly) has proposed that the length of the puncture needle is 100mm to 150mm. The specification of the primary retractor sheath 2 is 4Fr to 4.5Fr, and the length is 80mm to 120mm; the length of the primary sheath body 22 is 65mm, and the length of the primary insertion port 21 is 15mm; the puncture needle 1 is 115mm long, wherein the needle body 12 is 85mm long, the needle handle 11 is 30mm long, and the connector 13 is adapted to the primary insertion port 21, so the insertable length of the needle body 12 is 70mm.

[0018] The inlet sheath 4 has a specification of 4.5Fr to 5Fr and a length of 100mm to 150mm; the secondary expansion sheath 5 has a specification of 5Fr to 6Fr and a length of 80mm to 120mm. The inlet sheath 4 is 120mm long, wherein the sheath handle 41 is 30mm long and the inlet sheath body 42 is 90mm long; the secondary expansion sheath 5 is 80mm long, and the secondary expansion sheath 5 fits exactly with the inlet sheath body 42, and the front end of the inlet sheath body 42 extends 10mm beyond the secondary expansion sheath 5.

[0019] One defect of the PICC catheter placement minimally invasive skin expansion sheath assembly is: The proposed method involves an inner sheath that is only 1 cm longer than the outer sheath. This often results in the outer sheath entering the skin before the inner sheath enters the blood vessel, leading to failed insertion attempts, such as difficulty requiring additional blades for skin widening or inaccurate insertion outside the blood vessel. Our inner sheath is 4-4.5 cm longer than the outer sheath, ensuring successful skin widening and precise insertion into the blood vessel on the first attempt.

[0020] The original design required both a primary and secondary expansion sheath for skin expansion, but this utility model patent only requires one expansion sheath, omitting the primary expansion sheath process.

[0021] How to use: 1. A 21G puncture needle is used to puncture the target vein under ultrasound guidance. 2. Once blood return is observed, advance the guidewire, leaving 10-15cm of the guidewire outside the body. 3. Inject 0.3-0.5 ml of 2% lidocaine for local anesthesia. 4. Insertion of the novel blunt dissection micro-cannula sheath: The 10cm long inner sheath passes through the guidewire. The tip of the inner sheath, 4.5cm long, first enters the subcutaneous tissue while expanding the skin to reach the target vein. Subsequently, the 5.5cm long outer sheath, which is placed over the inner sheath, is inserted together with the inner sheath into the subcutaneous tissue and the target vein. 5. Remove the inner sheath and guidewire, fix the outer sheath, and insert the PICC catheter through the outer sheath into the target vein to reach the optimal position of the vena cava.

[0022] Beneficial effects: Extensive clinical data has shown that the inner sheath of the micro-cannula sheath is 4.5 cm longer than the outer sheath. This ensures that the inner sheath enters the blood vessel first, while the outer sheath penetrates the skin before entering. This method reliably guides the outer sheath into the blood vessel because the inner sheath not only dilates the skin but also acts as a guide. If the inner and outer sheaths differ by less than 1 cm, the inner sheath may not reach the blood vessel before the outer sheath penetrates the skin, leading to further wrinkling and twisting, resulting in failed delivery. It is also possible that the outer sheath fails to enter the blood vessel and is instead delivered into the subcutaneous tissue outside the blood vessel. This is more practical and feasible than the existing technology 2, where the inner sheath is only 1 cm longer than the outer sheath.

[0023] The inner sheath of this novel micro-insertion sheath is 10 (9.5-10.5) cm long, while the outer sheath is 5.5 (5-6) cm long. This ensures that the length is suitable for patients with a blood vessel depth ≥2 cm, and is also applicable to patients with a blood vessel depth <2 cm. The outer sheath diameter is about 2.2 mm. This diameter takes into account the rigidity of the insertion material and the damage to the skin, soft tissue and blood vessels. The above value is adopted to minimize the damage to the skin, soft tissue and blood vessels.

[0024] The outer sheath of the novel blunt dissection cannula is made of poly(fluoroethylene) propylene (FEP), which is an abbreviation for polytetrafluoroethylene and hexafluoropropylene polymer resin. Its hardness and strength are higher than those of polytetrafluoroethylene. Therefore, the outer sheath material of this invention is suitable for blunt dissection, while the outer sheath of the traditional 4.5F microcannula is made of polytetrafluoroethylene, which requires the use of a scalpel to dilate the skin. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the inner and outer sheaths of the micro-insertion sheath of this utility model. Detailed Implementation

[0026] like Figure 1 Tables 1 and 2 describe a novel blunt dissection cannula, comprising an inner sheath 1 and an outer sheath 2 tightly fitted over the inner sheath 1. The inner sheath 1 is slender, hollow, and spiky, and also includes an inner sheath handle 11, an inner sheath base 13, and an inner sheath insertion end 12. After fitting, the inner surface of the outer sheath 2 is tightly attached to the outer surface of the inner sheath 1, and is also hollow and spiky. The outer sheath 2 also includes an outer sheath base 21 and an outer sheath indwelling end 22. The length from the bottom of the inner sheath base 13 to the top of the inner sheath insertion end 12 is 10 cm, and the length from the bottom of the outer sheath base 21 to the top of the outer sheath indwelling end is 5.5 cm.

[0027] The outer diameter of the top of the inner sheath inlet 12 is 0.8 mm, and the outer diameter of the bottom of the inner sheath inlet 12 is 1.7 mm; the inner diameter of the top opening of the outer sheath inlet 22 is 1.6 mm, and the inner diameter of the bottom of the outer sheath inlet 22 is 1.78 mm.

[0028] The technical content claimed in this patent was used to conduct a comparative experiment with prior art 1. Specifically, the assembly kit of a traditional 14G cannula (outer sheath length 3.2cm) and a 4.5F vascular sheath (inner sheath length 7cm) was compared with the kit specifically designed for this patent (inner sheath length 10cm, outer sheath length 5.5cm). A comparative experiment was conducted on the success rate of sheath delivery on the first attempt in patients with vessel depths greater than 2cm using both methods; specific values ​​are shown in Table 1.

[0029] Conclusion: The success rate of sheath delivery in the experimental group was significantly higher than that in the control group (χ2=54.85, P<0.001).

[0030] The incidence of complications after catheterization in patients with a vascular depth greater than 2 cm was collected from the two methods and compared. The specific values ​​are shown in Table 2.

[0031] Conclusion: The incidence of bleeding complications in the experimental group was significantly lower than that in the control group (χ2=13.23, P<0.001). There was no statistically significant difference in the incidence of thrombosis, puncture site infection, and phlebitis between the two groups.

[0032] Table 1: Success rate of sheath delivery in one attempt for patients with blood vessel depth greater than 2 cm using the two methods.

[0033] .

[0034] Table 2: Comparison of complication rates after catheter placement in patients with a vessel depth greater than 2 cm between the two methods.

[0035] .

Claims

1. A novel blunt-touch dissection cannula, comprising an inner sheath and an outer sheath tightly fitted over the inner sheath. The inner sheath is slender, hollow, and spiky, and further includes a handle end, a base, and an insertion end. After fitting, the inner surface of the outer sheath is tightly attached to the outer surface of the inner sheath and is also hollow and spiky. The outer sheath also includes a base and an indwelling end, with a through hole at the top to facilitate the insertion end of the inner sheath extending from the opening of the indwelling end. The feature is that... The difference between the length from the inner sheath base to the top of the spiky inlet and the length from the outer sheath base to the outer sheath indwelling end is 4-4.5 cm.

2. The blunt dissection cannula sheath as described in claim 1, characterized in that: The length from the base of the inner sheath to the top of the spiky insertion end is 9.5-10.5 cm, and the length from the base of the outer sheath to the indwelling end of the outer sheath is 5-6 cm.

3. The blunt dissection cannula sheath as described in claim 2, characterized in that: The length from the inner sheath base to the top of the spiky insertion end is 10cm, and the length from the outer sheath base to the outer sheath indwelling end is 5.5cm.

4. The blunt dissection cannula sheath as described in claim 3, characterized in that: The outer diameter of the top of the inner sheath inlet is 0.8 mm, and the outer diameter of the bottom of the inner sheath inlet is 1.7 mm; the inner diameter of the top opening of the outer sheath indwelling end is 1.6 mm, and the inner diameter of the bottom of the outer sheath indwelling end is 1.78 mm.

5. The blunt dissection cannula sheath as described in claim 4, characterized in that: The outer diameter of the top opening of the outer sheath is 1.9 mm, and the outer diameter of the bottom of the outer sheath is 2.3 mm.

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