NEONATE UMBILICAL CATHETER
TECHNICAL FIELD
The present invention relates generally to a catheter, and more particularly, relates to an umbilical catheter for use in newborn infants.
BACKGROUND ART
Newborn infants can develop illnesses requiring treatment by means of umbilical catheters. For example, such catheters have been used widely to perform transfusions, blood samplings and blood pressure measurements. However, vessel blockage or vessel wall perforation, hemorrhaging, vascular spasms, infection, thrombosis and other complications have occurred in
« connection with the use of umbilical catheters to treat sick newborn infants.
The blood vessels of an infant are smaller in terms of length, internal diameter and wall thickness, and are thus more delicate and susceptible to perforation and inflammation during catheterization. Although various types of catheters have been developed which are suitable for use in.youth and/or adults, such catheters have been found too rigid and inflexible for infants.
Umbilical catheters have been developed heretofore, but have suffered from various disadvantages. Catheters utilizing cannulae formed entirely of polyvinylchloride (PVC) material are too rigid. In addition, a higher incidence of thrombosis has been associated with the use of PVC catheters. The use of radiopaque materials for locating a catheter with a radiograph, and the use of translucent materials for visual inspection of air or blood passing through the catheter, are well known in the art.
More recently, umbilical catheters have been developed utilizing two sections of tubing, the distal portioa being relatively more flexible than the proximal portion of tubing. Catheters formed of silicone elastomer were found to have several advantages over PVC catheters in the article entitled "Reduced Thrombus Formation with Silicone Elastomer (Silastic) Umbilical Artery Catheters" which appeared in Volume 56, Mo. 6 of
Pediatrics in December, 1975. Although more flexible, the silicone elastomer catheters of the prior"art have been somewhat difficult to insert, as well as unecessarily complex in construction and thus relatively expensive to manufacture. A need has thus arisen for a new umbilical catheter of improved construction.
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DISCLOSURE OF INVENTION
The present invention comprises an improved neonate umbilical catheter which overcomes the foregoing and other difficulties encountered in the prior art. In accordance with the invention, there is provided an umbilical catheter comprised of a fitting and two sections of tubing connected together serially. The two sections of tubing are formed of elastomeric material. A removable stylet -is preferably used with the catheter to facilitate insertion into a blood vessel. The catheter herein is less expensive to manufacture than those of the prior art and reduces the incidence of complications in catheterization of newborn infants.
More particularly, the present invention comprises a neonate umbilical catheter comprised of a hub or fitting, a proximal section of tubing, and a distal section of tubing connected together in serial relationship. In the preferred embodiment, the proximal tubing section is connected to the hub by means of a rigid insert, inner sleeve and ring. The proximal tubing section is usually relatively less flexible than the distal section. The two sections of tubing are interconnected by stretching the proximal end of the distal section over the distal end of the' proximal section. In accordance with the preferred construction, the invention includes a removable stylet extending through the catheter for stiffening the device during insertion into a blood vessel.
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BRIEF DESCRIPTION OF DRAWING
A more complete understanding of the invention can be had by referring to the following Detailed Description in conjunction with the accompanying Drawing, wherein: FIGURE 1 is a top view of an umbilical catheter incorporating the invention;
FIGURE 2 is an enlarged view of the proximal portion of the invention; and
FIJGURE 3 is an enlarged view of the medial portion of the invention.
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DETAILED DESCRIPTION
Referring now to the Drawing, wherein like reference numerals designate like or corresponding parts throughout the views, and particularly referring to FIGURE 1, there is shown a catheter 10 incorporating the invention.
Catheter 10 is especially adapted for transfusions, blood pressure measurement and blood sampling in newborn infants. Under normal conditions, catheter 10 would be enclosed within a sterile package for shipment and storage prior to use.
Catheter 10 includes a fitting or hub 12, a proximal section of tubing 14, and a distal section of tubing 16 connected together in serial relationship. In accordance with the preferred embodiment, a removable stylet 18 is provided with catheter 10 to facilitate insertion thereof into a patient.
Tubing 14 comprises a suitable length of hollow material of transparent or translucent construction to enable visual observation of fluids passing through catheter 10. Blood coloration for instance can thus be readily monitored through tubing 14 without removal of blood samples. Tubing 14 can be constructed of any suitable material, such as vinyl, TEFLON brand material or other polymers. In the preferred embodiment, tubing 14 is of PVC material and is approximately 150 millimeters in length, 2.0 millimeters outside diameter, and 1.2 millimeters inside diameter.
The distal section of tubing 16 is relatively more flexible than tubing 14 and is preferably radiopaque to facilitate x-ray determination of the location of catheter 10. Tubing 16 can be formed of any suitable relatively soft, pliable material such as silicone elastomer. In accordance with the preferred construction, tubing 16
is constructed from silicone elastomer having a length of approximately 200 millimeters, an outside diameter of about 1.7 millimeters, and an inside diameter of about 1.0 millimeters. FIGURES 2 and 3 illustrate the constructional details of catheter 10. FIGURE 2 in particular illustrates the connection between hub 12 and tubing 14. Hub 12 includes a circular flange 20 at the proximal end and several longitudinal ribs 22 about the distal end thereof. Hub 12 can be formed of plastic or other suitable material. A low volume chamber 24 extends through hub 12. Chamber 24 includes a tapered circular socket portion at the proximal end of hub 12, in which the handle 26 of stylet 18 is removably seated. An insert 28, which is preferably formed of metal, extends outwardly from chamber 24 through the narrow end thereof at the distal end of hub 12. Insert 28 and hub 12 are secured together by means of hub shoulder 30 positioned at the junction between the two portions of chamber 24. .Insert 28, which is of hollow construction is thus in fluid communication with the interior of hub 12.
Tubing 14 extends from a skirt 32 formed at the outside end of insert 20 and over an inner* sleeve 33. The proximal end of sleeve 33 extends underneath skirt
33 and is secured to insert 28 when the skirt is crimped inward. Tubing 14 is securely clamped to sleeve 33 by ring 34. It will thus be apparent that a rigid coupling including insert 28 and inner sleeve 33 provides reinforcement at the connection between hub 12 and tubing 14.
A wire 36 extends from handle 26 of stylet 18 through hub 12, insert 28, tubing 14, and a portion of tubing 16. Stylet 18 is thus comprised of a handle 26 and a
length of flexible wire 32, which can be a section of straight wire or helical wound wire. Due to the greater flexibility required of umbilical catheters, it has been desirable to utilize stylet 18 to facilitate insertion of catheter 10, after which the stylet is withdrawn.
FIGURE 3 illustrates the connection between tubing 14 and tubing 16. The proximal end 16a of tubing 16 is stretched over the distal end 14a of tubing 14. In the preferred embodiment, wherein tubing 16 is formed of silicone rubber, this can easily be done by softening the tubing with a solvent and pulling it over tubing 14. This particular form of connection between the two sections of tubing in catheter 10 provides a tight but flexible connection which facilitates manufacture of the catheter and comprises an important aspect of the invention. A flexible outer sleeve 38 of silicone elastomer material, for example, can be provided about the connection between tubing 14 and tubing 16, if desired. From the foregoing, it will be understood that the present invention comprises a neonate umbilical catheter having several advantages over the prior art. One significant advantage involves the manner of interconnecting the two sections of tubing to retain sufficient flexibility. Another advantage is the use of a rigid insert and inner sleeve to reinforce the connection between the hub and the proximal section of tubing. Other advantages will suggest themselves to those skilled in the art.
Although a particular embodiment of the invention has been illustrated in the accompanying Drawing and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiment disclosed, but is intended to embrace any alternatives, modifications, and rearrangements and/or substitutions of elements as, fall within the spirit and scope of the invention.
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