Flexible Protective Sheath For Catheter

Abstract

This invention pertains to the use of catheters and the sterilized protection of their exterior surface as they are inserted into a patient and particularly for catheters used with intravascular feedings and transfusions and pressure determining systems, suprapubic catheterization and spinal taps. A needle or stylet within the catheter is used for the initial penetration and usually assembled and packaged with the catheter and sheath of this invention. The protective sheath is a very thin plastic tubular member which is a loose sliding fit on the outer diameter of the catheter. This sleeve remains mounted on the catheter as the catheter is inserted into the patient. The loose sheath is disposed to collapse upon itself up to and around the hub of the inserting catheter. As and during its collapse the sheath acts as a guard to prevent contamination of the inserting member as it is advanced into the patient. The sheath member may be approximately one-third larger than the diameter of the catheter on which it is mounted and is approximately one-thousandths of an inch in thickness which is just sufficient to permit heat sealing to form the tube and to provide a reasonable protection against manipulative handling. In its initial mounted condition the end of the sheath is brought to or very near the sharp end of the inserting member.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-Part of my U.S. Pat. Application Ser. No. 312,952, filed Dec. 7th, 1972 and upon the acceptance of this application expressly abandoned.

Description

BACKGROUND OF THE INVENTION

1. FIELD of the INVENTION

With reference to the classification of art as established in the U.S. Patent Office the present invention pertains to the general Class entitled, "Surgery" (Class 128) and more particularly to the subclass entitled, "catheter" (subclass 214).

DESCRIPTION OF THE PRIOR ART

In the present use of catheters at least the penetrating portion is generally in a sterile condition when packaged and shipped and is maintained so until time of use. Conventionally at the time of use the protective cover is removed and by manipulation and grasping the exterior surface the catheter is inserted into the arm, leg or other portion of the patient. Although in an initially sterile condition the handling necessary for satisfactory insertion of this catheter into the patient often causes this exterior surface to be pressed against the skin of the patient during manipulation and prior to insertion below the skin. Although the patient may have been locally cleaned prior to insertion into the area, this skin is not in a sterile condition particularly where the insertion is a difficult one. In addition, the manipulator's fingers may touch the shaft portion adjacent to the grasped hub portion of the catheter. In addition, the skin entrance site may act as an entrance for bacteria.

The present invention provides an additional sheath for the exterior surface of the catheter. This added sheath is loosely retained in a protecting position until inserting penetration of the catheter into the patient is begun. As the insertion into and through the skin continues the sheath engages the skin at the penetration point and slids up the catheter or needle. The sterile catheter is not exposed to any outside condition but is slid through the skin opening. This sheath as it collapses usually folds in an accordion-like manner as it slides up to the hub of the catheter. In addition to providing a protection of the now inserted catheter the collapsed sheath also shields that uninserted catheter portion between the skin and hub and also provides a barrier to entrance of bacteria into the skin puncture.

SUMMARY OF THE INVENTION

In this invention a catheter which is slidably mounted on a needle or stylet has its exterior diameter forward of the hub enclosed in a protective sheath. It is contemplated that this sheath be tubular in configuration and plastic in construction and have a wall thickness of approximately one-thousandths of an inch. The sheath is a loose sliding fit upon the exterior diameter of the catheter. This sheath as it collapses moves generally into an accordion-like accumulation and readily is so formed since it is a very thin sheath which is approximately one and one-half times the diameter of the catheter. In its shortened accumulated condition the several folds of this thin plastic occupy very little space when the catheter has been inserted to the desired depth into the skin of the patient. The sheath is not removed from the catheter during its use by provides a protective cushion around the skin puncture.

In addition to the above summary the following disclosure is detailed to insure adequacy and aid in understanding of the invention. This disclosure, however, it not intended to prejudice that purpose of a patent which is to cover the inventive concept no matter how it may later be disguised by variations in form or additions. For this reason there has been chosen a specific embodiment of the flexible sheath as adopted for use on a catheter. This specific embodiment has been chosen for the purposes of illustration and description as shown in the accompanying drawing wherein:

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 represents a sectional side view showing a sheath mounted on a catheter, this view in an enlarged scale to show the relationship of the sheath member in mounted condition on a catheter before the insertion thereof, and

FIG. 2 represents the view of the catheter and sheath of FIG. 1 after insertion of the catheter into the body of the patient, the sheath during the insertion has been collapsed to form accordion folds in the portion between the hub of the catheter and the entrance into the skin of the patient.

In the following description and in the claims details are identified by specific names for convenience; these names, however, are intended to be generic in their application. Corresponding reference characters refer to like members throughout the two figures of the drawing but it should be understood that structural details may be modified in various respects without departure from the concept and principles of the invention.

DESCRIPTION OF THE SHEATH

Referring now to the drawing and FIGS. 1 and 2, there is depicted a catheter 10 which is attached to a hub 12 in a conventional manner. This catheter is slidably mounted on a needle or stylet 14 which, typical of the percutaneous instruments used with this invention, has a sharpened end 16 adapted for penetration into and below the skin of the patient. Slidable on and providing a covering for the body penetrating extent of the catheter is a sheath member 18 which, as depicted in enlarged cross-section, is disportionate in thickness in order to illustrate a thickness. This sheath member 18, in practice, is only about a thousandth of an inch in thickness and when mounted on the catheter extends from the hub end 12 to the sharpened tip portion 16 of the penetrating means. Preferably the loose sheath terminates at or very near the rear of the sharpened point.

Referring now in particular to FIG. 2, it is to be seen that the catheter 10 has penetrated the skin and has been inserted into the body 20 of the patient. Sheath 18 has been pushed up the catheter as the catheter has penetrated the skin and passed through the opening and into the patient. The forced collapse of the sheath causes a folding upon itself in a generally accordion-like manner and during the collapse acts as a guard to prevent accidental contact with the outer surface of the catheter and contamination thereof as the catheter is moved through the skin and into the body of the patient.

USE OF THE SHEATH OF THIS INVENTION

Catheters or other like members which are inserted into the arms, legs or other portions of the patient are generally of a diameter of an eighth of an inch or less. The sheath 18 of this invention is deliberately made several thousandths of an inch larger in diameter than the catheter 10 on which it is mounted. In particular, assume that a catheter 10 is three-thirty-seconds of an inch in diameter, the inside diameter of the sheath would be approximately five thirty-seconds to three-sixteenths of an inch in diameter. As the catheter with the sheath in mounted condition is inserted into and through the skin and into the tissue of the patient 20, the sheath 18 whose wall is approximately one-thousandths of an inch in thickness has its distal end brought into engagement with the skin adjacent the penetration opening. During penetration of the end and entering length of the catheter the sheath end continues to engage the skin of the patient.

As the insertion of the catheter into the patient continues the very thin plastic sheath which is quite supple, crumples in an accordion-like manner and slides up the catheter in accordance with the progress of the penetration. This accordion-like sheath portion is disposed between the skin entrance and the hub 12 of the catheter. As the insertion is made to almost the full depth of the catheter, the sheath 18 is bunched together to assume more-or-less the condition as seen in FIG. 2. During the penetration the force necessary to crumple and slide the sheath along the catheter is minimal as the wall thickness of the sheath is only sufficiently rigid to keep the sheath in a more-or-less extended condition which is overcome to collapse or fold the sheath as the penetration of the skin is accomplished. Sheath 18 which protects the catheter 10 is a very thin, substantially transparent tubular member. It may be an extruded plastic tube or may be made by longitudinal heat sealing of sheet plastic material. When the sheath is made of one- to two-thousandths of an inch thick supple plastic, a hundred accordion folds may be easily made and will occupy a length which may be less than a quarter of an inch. As the catheter is not intended for full insertion into the patient, the bunched, accordion-like, collapsed sheath does not impede the use of the catheter. The plastic which is used to make the sheath is preferably quite inexpensive and may be one of many acceptable for use on or near the skin of a patient for periods of time up to a few days.

The conditions to which the sheath is subject influences the selection of the material from which it is made. Some of the conditions include sterilization, storage, medicants, etc. A use and service characteristics chart enables the manufacture of the percutaneous appliance to select the material for the sheaths and manufacture may be by heat sealing and/or extrusion.

Terms such as "in," "out" and the like are applicable to the thin plastic sheath shown and described in conjunction with the drawing. These terms are merely for the purposes of description and do not necessarily apply to the position in which the sheath and percutaneous appliance may be constructed or used.

While a particular assembly has been shown and described it is to be understood the invention is not limited thereto and protection is sought to the broadest extent the prior art allows.

Claims

What is claimed is:

1. In combination with a flexible catheter for percutaneous use with a patient there is provided a flexible protective sheath slidably mounted on the midshaft portion, said combination including: (a) a flexible catheter of determined length and having an entering end and a hub end and with that midshaft portion of said catheter forwardly of the hub having a selected outside relatively constant bore; (b) a stiff bore puncturing member slidably carried in the bore of the catheter and removable through the hub end after the desired penetration of the skin of a patient has been achieved, and (c) a very thin flexible plastic sheath of tube-like form whose wall thickness is less than two-thousandths of an inch in thickness and formed and sized so as to provide a sliding fit on the outer diameter of the midshaft of the catheter which it is to protect, the tube size being about one-third larger than the midshaft portion of the catheter for which it provides the protection, said sheath in an unmounted condition being open at both ends and when mounted having a length sufficient to extend from the skin-entering end of said catheter to a determined larger stop portion such as the hub of the catheter, said mounted sheath particularly adapted to engage the skin at the point of penetration and to be engaged by the skin at this opening to prevent further forward progress of the sheath whereat said sheath slides on the midshaft of the catheter and to the extent of shortening the sheath length progressively collapses into accordion-like folds as the catheter is caused to enter the entrance into and through the skin, the sheath providing a sliding guard continuously protecting against accidental contact of the outer surface diameter of the uninserted portion of the midshaft of the catheter by the user of the instrument during both the initial and progressive insertion through the skin, said sheath in its folded and unfolded portion remaining on the uninserted portion of the midshaft of the catheter during inserted use in a patient.

2. A combination of sheath and catheter as in claim 1 in which the skin puncturing member is a metal stylet.

3. A combination of sheath and catheter as in claim 1 in which the skin puncturing member is a hollow metal needle.