Stylet and connector therefor

Abstract: The stylet as described comprises a stylet body and a connector for connecting the stylet to a catheter. Said stylet body is composed of a piece of wire bent double and twisted together to form a rounded end serving as a distal end at one end. The connector has a stylet body connecting portion for holding a proximal end of said stylet body and means for fixedly holding the catheter to prevent the catheter from slipping out of the stylet during use. This stylet is prevented from injuring blood vessels and enables to correctly and safely insert a catheter to a desired position with ease.

Description: The present invention relates to a stylet used for assist insertion of a catheter into the blood vessel and to a connector for holding a stylet and connecting it to a catheter. More particularly, it relates to a stylet to be inserted into a lumen of a venous catheter for total parenteral nutrition to give a desired rigidity to the catheter and to a connector for holding the stylet in the lumen thereof, which makes it possible to allow a medical solution to flow into the catheter through the lumen thereof. When inserting a venous catheter for total parenteral nutrition or an endotracheal tube, it is general practice to insert a metal wire or a stylet into a catheter to give some. rigidity to the catheter or tube since such a catheter is too soft to insert them into the blood vessel or trachea without causing bending of the catheter. The stylet is bent into a desired shape as occasion demands. For example, in case of intratracheal intubation, the stylet is bent into a shape corresponding to the shape of respiratory tract of a patient whose larynx being expanded. In general, however, the stylet is of a metal such as stainless steel and has an acute-angled end. Thus, the stylet of the prior art has disadvantages that vessel walls or trachea walls may be injured by the distal end of the stylet protruded from the catheter during insertion of the catheter. Further, it is occasionally required to use the catheter filled with heparinized saline to perform priming operation. In such a case, it is necessary to remove the stylet from the catheter to fill the catheter with heparinized saline. In addition, it requires a great deal of skill to insert the stylet of the prior art into a correct position of the superior vena cava through the subclavian vein. US-A-4 496 347 relates to a stylet to be used in combination with a feeding tube assembly for administration or aspiration of fluids to a patient comprising a wire with an elongated loop of variable length and width at its distal end. It is therefore an object of the present invention to provide a stylet which is prevented from injuring blood vessels. Another object of the present invention is to provide a stylet which enables to correctly and safely insert a catheter to a desired position with ease. Still another object of the present invention is to provide a stylet connector which enables to perform priming operation without removal of a stylet from a catheter. According to the present invention, there is provided a stylet comprising a stylet body and a connector for connecting the stylet to a catheter, said stylet body being composed of a piece of wire bent double and twisted together to form a rounded end serving as a distal end at one end, said connector having a stylet body connecting portion for holding a proximal end of said stylet body and means for fixedly holding the catheter to prevent the catheter from slipping out of the stylet during use. In a preferred embodiment, the stylet body is bent at a distal portion at a certain angle to allow the catheter to be correctly inserted into a desired place in the blood vessel. In this case, the connector may be provided with a certain mark indicating a bending direction of the stylet body. According to the present invention, there is also provided a connector comprising a tubular body having at one end a stylet body connecting portion and at the other end an inflow port for medical solution, said stylet body connecting portion holding the stylet body and providing paths for flow of a medical solution from a lumen thereof without removal of the stylet when performing the priming operation. The stylet connector further includes a hood-shaped fixing member rotatably mounted on the distal end of the tubular body to form a means for fixing a catheter. Preferably, the stylet body connecting portion is provided integrally and coaxially with the tubular body. These and other objects and features of the present invention will be explained in detail, making reference to the accompanying drawings which show one preferred embodiment of the present invention, and in which: Fig. 1 is a plan view illustrating a stylet according to the present invention; Fig. 2 is an enlarged view of a distal end of the stylet shown in Fig. 1; Fig. 3 is an enlarged view of a connector used in the stylet of Fig. 1; Fig. 4 is a sectional view taken along a line X-X in Fig. 3; Fig. 5 is an enlarged side view of the connector taken from the direction of an arrow A shown in Fig. 4; Fig. 6 is a plan view illustrating the stylet of Fig. 1 with a catheter into which the stylet is inserted. Referring now to Fig. 1, there is shown a stylet S according to the present invention, which comprises a stylet body 1 and a stylet connector 2 for attachment of the stylet to a catheter. The stylet 1 is preferably bent at a certain angle at a certain position to form an angled distal portion 11, though the stylet body 1 may be formed in a straight line. The connector 2 comprises a tubular member having at one end a stylet body connecting portion 24 and at the other end an inflow port 25 for a liquid medicine. The connector 2 is provided with a hood-shaped fixing member 23 rotatably mounted on the tubular member on the side of its distal end to form a means for fixing a catheter 3. In use, as shown in Fig. 6, the stylet body 1 is inserted into a lumen of the catheter 3 through a connector 31 of the catheter and then fixed to the catheter 3 by engagement of the connector 31 with the catheter-fixing means 23. As best shown in Fig. 2, the stylet body 1 is composed of a piece of wire bent double and twisted together to form a hairpin or rounded end 12. This stylet body may be prepared, for example, by bending a piece of stainless steel wire double to form a rounded distal end 12 and then twisting the doubled wire together. The stylet body 1 is so attached to the connector 2 that the rounded end 12 becomes an distal end of the stylet body 1. The pitch P of the twisted wire varies with a material and size of the wire. In case of a piece of stainless steel wire with a diameter of 0.2 mm, it is preferred to twist the wire at a pitch of 5 to 8 mm, preferably, 6 mm. Although the stylet body 1 may be used in a straight form, the stylet body 1 of this embodiment is bent at a certain position away from the distal end at a certain angle so that the catheter can be correctly inserted into a desired place in the blood vessel of a patient. The size of the stylet body 1 varies with its use. In case of a stylet for superior vena cava, the stylet body 1 preferably has a length of 300 mm and is bent at an angle of 10 to 15 at a distance of 12 mm from the distal end 12. The stylet connector 2 has the stylet body connecting portion 24 where a proximal end of the stylet body 1 is fixed, and a means for fixing the catheter 3. The connector 2 comprises of a tubular member made of a metal such as stainless steel or a synthetic resin such as polypropylene, polyethylene, polyester, ABS resin or the like. A small-sized portion 21 of the connector 2 is lure-tapered to ensure engagement with a connector 31 of the catheter 3 having a female lure-tapered shape. As shown in Figs. 3 to 5, the stylet connector 2 has a tapered, lumen 27 and is provided with the stylet body connecting portion 24 integrally and coaxially with the tubular member so as not to obstruct fluid paths 27. Thus, when performing priming procedures, a medical solution fed into the lumen of the stylet connector 2 is allow to flow into the catheter 3 through the paths 27 without removal of the stylet S from the catheter 3. The stylet body connecting portion 24 has a through-hole 241 for insertion of the stylet body 1 coaxially with the axis of the tubular member. A large-sized proximal portion 22 is provided with a medicine port 25 of a female lure-tapered shape and has double-start threads 221 close to the fluid port 25. A suitable injection means such as syringe (not illustrated in the drawings) can be connected to the fluid port 25 to inject a medical solution such as physiological saline or heparinized physiological saline into the catheter 3. The double-start thread is intended to connect a lock-type syringe or a lock connector such as lock-type three-way valve to the stylet. In order to make it easy to perform insertion of the catheter 3, the proximal portion 22 may be provided with a mark 26 indicating the bending direction of the distal end 11 of the stylet 1. The hood-shaped catheter-fixing means 23 is slidably mounted on an outer wall of the tubular member on the side of the distal end of the connector 2 to prevent the catheter 3 connected to the connector 2 from falling away from the stylet. The catheter-fixing means 23 is movable in the direction parallel to the axial direction of the tubular member but is prevented from falling away from the tubular member. The inner wall of the hood-shaped portion of the catheter-fixing member 23 is provided with female threads 231 intended to engage with male engaging means (not shown in the drawings) such as double-start threads or male screw threads. As explained above, the stylet of the present invention have the following advantages: (1) The rounded distal end of the stylet enables to protect the blood vessel from injury by the protruded distal end of the stylet when inserting the stylet into the catheter; (2) if the stylet has a distal end bent at a certain angle, it is possible to correctly insert the catheter into the blood vessel with ease as the bent distal end enables to minimize operation by mistake during insertion of the stylet; (3) the connector with a medicine port makes it possible to perform priming operation without removal of the stylet being inserted in the catheter, to improve the operation of the procedures and to reduction in time required for surgical operation; and (4) it is possible to avoid fear of secondary infection as the priming operation can be done without removal of stylet from the catheter.

Claims: A stylet assembly for a catheter comprising a stylet body (1) and a connector (2) for connecting the stylet to a catheter (3), said stylet body being composed of a piece of wire bent double and twisted together to form a rounded end (12) serving as a distal end at one end, and said connector comprises a tubular member and means (23) for fixing the catheter to prevent the catheter from slipping out of the stylet during use, wherein said tubular member having at one end a stylet body connecting portion (24) for holding a proximal end of said stylet body, and at the other end an inflow port (25) for a medical solution, said stylet assembly is characterized by a fluid path, (27) extending through the tubular member between the ends. The stylet according to claim 1, wherein the stylet body is bent at a distal portion thereof at a certain angle to allow the catheter to be correctly inserted into a desired place in the blood vessel. The stylet according to claim 2, wherein the connector is provided with a mark indicating a bending direction of the stylet body. The stylet according to claim 1, 2 or 3, wherein the connector comprises a hood-shaped connecting means (23) roatably mounted thereon for attachment to a catheter, and said stylet body connecting portion being so formed as to provide at least one path for flow of the medical solution from a lumen (27) thereof without removal of the stylet when performing the priming operation. The stylet according to any of claims 1 to 4, wherein the stylet body connecting portion is coaxially united with the tubular member. A stylet assembly according to any of claims 1 to 5, wherein the stylet body connecting portion (24) comprises a central through-hole (241) for holding the proximal end of the stylet and wherein at least one flow passage (27) in the stylet body connecting portion (24) is arranged around the through-hole (241) on the distal end of the connector.

Inventors: FUJITA NOZOMU, TSUJIKAWA HAJIME, FUJITA, NOZOMU, TSUJIKAWA, HAJIME
Applicants: NIPRO CORP, NIPRO CORPORATION
Application year: 1996
Main classification: A61M25
IPC codes: A61M25, A61J15