Catheter placement unit with needle removal provision and method of use

A catheter placement unit for use with an introducer needle and an introducer catheter including a hollow tube and a fitting at one of its ends. The placement unit comprises a connector having an internal bore and including a male fitting member for mating with the catheter fitting to provide a connection. A protective sheath is secured to the connector and it includes a hole, closable elastic member or the like in its periphery for allowing insertion of the needle therethrough and into the bore of the connector. A length of flexible, hollow catheter tubing is movably positioned within and enclosed by the sheath. A method of placing a catheter into a patient includes the steps of mating a connector of a catheter placement unit, substantially as described above, to a fitting on an introducer catheter. A needle is inserted through the periphery of the sheath and through the connector into the lumen of the introducer catheter so that the tip of the needle extends slightly beyond its end. The introducer catheter and needle are inserted into a patient. While leaving the introducer catheter in position in the patient, the needle is withdrawn from the unit. With the flexible hollow tubing still enclosed by the sheath, it is manipulated internally through the connector and the introducer catheter and then into the patient.

BACKGROUND OF THE INVENTION 
The present invention relates to a catheter placement unit suitable for 
insertion into the blood system and other body tissue of a patient, and 
also concerns a placement system for inserting the catheter into a patient 
and its method of use. 
Catheters having a generally elongate axial dimension are utilized in 
intravenous therapy for a number of purposes including delivery of 
intravenous liquid and pressure monitoring services. These catheters are 
normally introduced into the patient's vein at an extremity and threaded 
to a major vein, or ultimately, to the heart. In this regard, the central 
venous pressure may be readily measured and monitored with compatible 
equipment. Introduction of the catheter into the patient generally poses 
the area of difficulty when using a device of this type. 
Prior catheter placement units or systems have used a metal introducer 
needle for venipuncture purposes and also to provide a passage for the 
catheter into the venous system. Many prior systems, however, have been 
designed to leave the introducer needle in position in the patient's vein 
while the extended catheter is slidably pushed through the needle and then 
into the patient. Catheter devices of this type are typified in U.S. Pat. 
Nos. 3,314,427 and 3,055,361. One of the problems associated with this 
technique is the danger of the catheter, generally made of flexible 
plastic, being cut or severed as it passes the extremely sharp point on 
the needle. 
Other catheter placement units have been proposed which have recognized the 
inherent problems of leaving the introducer needle in the patient during 
catheter use and have therefore provided for removal of the needle. One 
technique has been to use an introducer catheter with the needle, but 
without the extended catheter being attached during venipuncture. After 
venipuncture, the needle is withdrawn, leaving the introducer catheter 
inserted in the patient's vein. This, of course, introduces another 
problem, namely, blood escaping from the patient's vein through the 
intravenous catheter. Accordingly, these catheter placement devices have 
had to provide some means of preventing the escape of blood, either by 
using a seal on the catheter device or the application of digital pressure 
above the insertion site, or some combination thereof. As soon as the 
introducer needle is withdrawn, the catheter is then generally connected 
to the introducer catheter whereupon it is slidably inserted through the 
catheter and then into the patient's vein. Devices of this type are 
typified in U.S. Pat. Nos. 3,825,001 and 3,757,771. It can be seen, that 
these type catheter units which provide for the removal for the needle are 
not "closed systems." In other words, the catheter is not attached to the 
introducer needle-introducer catheter combination upon original insertion 
into the patient; such attachment is only made after the needle is 
withdrawn. Accordingly, the need for further improvements is recognized in 
the utilization of catheter placement units and their introduction into a 
patient. 
SUMMARY OF THE INVENTION 
A catheter placement unit of the present invention is intended for use with 
an introducer needle and an introducer catheter including a hollow tube 
and an integral or attached fitting at one end of the tube. Comprising the 
placement unit is connection means having a bore therethrough and 
including means for mating with the fitting to provide a connection 
therewith. When this connection is made, the bore is adapted to be aligned 
with the lumen of the tube. A protective sheath, preferably flexible, is 
secured to the connection means and includes means in its periphery for 
allowing insertion of the needle therethrough and then into the bore and 
the lumen of the introducer catheter. A length of flexible, hollow tubing, 
serving as the catheter, is movably positioned within and enclosed by the 
sheath. In use, the connection means is adapted to be connected to the 
fitting with the needle being insertable through the insertion means in 
the sheath and through the bore and introducer catheter to provide means 
for venipuncture. After the needle is withdrawn, the flexible tubing, 
while enclosed by the sheath, is adapted to be manipulated through the 
bore and the hollow tube of the introducer catheter and into the patient. 
Another aspect of the present invention is a catheter placement system 
including a catheter placement unit substantially as described above in 
combination with an introducer catheter including a hollow tube and a 
fitting at one end thereof. The catheter placement unit is connected to 
the introducer catheter so that a bore in the connector of the catheter 
placement unit is aligned with the lumen of the tube of the introducer 
catheter. This combination further includes an introducer needle inserted 
through the periphery of the protective sheath and extending through the 
bore and the lumen of the tube so that the needle tip extends slightly 
beyond the distal end of the tube. Both the needle and tube are inserted 
into a patient during use. After the needle is withdrawn from the unit 
through the sheath, the flexible tubing serving as a catheter, while still 
enclosed by the sheath, is adapted to be manipulated through the bore and 
the lumen of the introducer catheter and then into the patient. 
Preferably, the protective sheath of the catheter placement unit is 
removable after the catheter is in position in the patient. 
A further aspect of the present invention is a method of placing a catheter 
into a patient. This method includes the step of mating a connector of a 
catheter placement unit, substantially as described above, to an 
introducer catheter having a fitting on one end thereof. An introducer 
needle is inserted through the periphery of the sheath of the catheter 
placement unit, and through its connector and the hollow tube of the 
introducer catheter so that the tip of the needle extends slightly beyond 
the distal end of the tube. Both the needle and the tube are then inserted 
into a patient. While leaving the tube of the introducer catheter in 
position in the patient, the needle is withdrawn from the unit. This 
method further includes manipulating the flexible hollow tubing serving as 
the catheter, while enclosed by the protective sheath, through the 
connector and the hollow tube of the introducer catheter and then into the 
patient. An appropriate connection from, for instance, an intravenous 
solution administration set or a pressure monitoring device, is then made 
for utilization of the catheter which has been positioned in the patient. 
From the structural standpoint, the catheter placement unit, system and the 
method of use, are notably different from prior catheter placement 
devices. For instance, the catheter placement unit of the present 
invention is a "closed system," inasmuch as the catheter, covered by a 
protective sheath, is assembled to the introducer catheter-introducer 
needle combination upon original introduction into the patient. This 
offers the advantage of having a completely assembled unit without the 
need for additional connection steps which many of the prior art devices 
have relied upon. In addition, the catheter placement unit and system of 
the present invention provides for removal of the needle after the 
original insertion so that the catheter may function without the needle 
remaining in the patient. By removing the needle, the concern of cutting 
or severing the catheter upon movement into the patient's vein is 
eliminated since the sharp point of the needle is withdrawn before the 
catheter tubing is slid into place. Thus, the present invention provides, 
for the first time, a catheter placement unit and device for its 
introduction into the patient which is essentially a "closed system" in 
which the introducer needle is withdrawn before the catheter tubing is 
moved into the patient.

DETAILED DESCRIPTION 
While this invention is satisfied by embodiments in many different forms, 
there is shown in the drawings and will herein be described in detail a 
preferred embodiment of the invention, with the understanding that the 
present disclosure is to be considered as exemplary of the principles of 
the invention and is not intended to limit the invention to the embodiment 
illustrated. The scope of the invention will be pointed out in the 
appended claims. 
Adverting to the drawings, particularly to FIG. 1, there is illustrated the 
preferred catheter system 10 of the present invention. This system has 
three basic components: an introducer catheter 11, an introducer needle 12 
and a catheter placement unit 14. 
Introducer catheter 11 includes a slender, hollow tube 15 which is open at 
both ends, with the distal end 16 of the tube being slightly tapered. A 
hub 18 serves as a fitting at the other, or proximal, end of tube 15. Hub 
18 is also hollow so as to communicate with the lumen of tube 15 which 
extends substantially axially from hub 18. The hub further includes an 
internal tapered surface which, together with the hollow portion of the 
hub, serves as a female fitting connection for reception of catheter 
placement unit 14. This connection will be described in greater detail 
hereinafter. 
Introducer needle 12 includes a slender barrel 19 with a sharp tip 20 at 
one of its ends. A handle 21 is at the other end of barrel 19; this handle 
may also serve as a fitting or connector for possible delivery of 
solutions through the needle, if desirable. Barrel 19 is preferably a 
smooth surfaced metal which is adapted to slidably fit inside the lumen of 
tube 15. It is sized in the particular system of this invention to slide 
within hollow tube 15 so that needle tip 20, upon assembly, extends 
slightly beyond distal end 16 of the tube. 
Turning to the description of catheter placement unit 14, it includes, 
generally, a connector 22, an elongated protective sheath 24, and, 
enclosed by sheath 24 and positioned within, a length of flexible, hollow 
tubing 25 which is preferably elongated to serve as an extended catheter. 
At the end of flexible tubing 25 facing away from connector 22 is a 
fitting 26 to which a subsequent connection may be made to an 
administration set for delivery of fluids or a pressure monitoring device 
or the like. 
Referring now to FIGS. 2-4, in conjunction with FIG. 1, connector 22 is 
illustrated in greater detail. This connector includes a substantially 
cylindrical collar 28 with an internal bore 29 extending therethrough. 
Bore 29 is stepped at two places to include shoulders 30 and 31. The 
portion of bore 29 extending outwardly from shoulder 30 has a slight taper 
32 in order to receive a compatible tapered retaining ring 34 therein. 
Retaining ring 34 is also substantially cylindrically shaped and includes 
a concentric opening 35 therein. Opening 35 of ring 34 when inserted in 
collar 28 serves as an extension of bore 29. Positioned within opening 35 
in a relatively tight fit is a male fitting member 36, which has its male 
fitting portion 38 extending substantially axially. Male fitting member 
36, and in particular the fitting portion 38, is adapted to mate with the 
internal tapered surface of hub 18 on the introducer catheter to provide 
the connection therewith. Male fitting member 36 includes a substantially 
concentric passage 39. Passage 39 is preferably sized to first allow 
barrel 19 of the introducer needle to slide somewhat snugly therethrough, 
and then subsequently to provide a similar fit for flexible hollow tubing 
25. At the interior end of passage 39 is a somewhat larger cavity 40 which 
is adapted to receive a portion of fitting 26 after catheter tubing 25 is 
completely positioned within the patient. Passage 39 is adapted to 
communicate with bore 29 through cavity 40 so that both the introducer 
needle and the catheter tubing can be moved through connector 22. The fit 
of male fitting member 36 in ring 34 is such that it is separable from the 
ring and collar upon the application of a small amount of manual pressure 
by the fingers. Ring 34 assists in providing a relatively snug fit of male 
fitting member 36 to the collar, while allowing ready separability and 
disengagement when it is time to remove the collar from the male fitting 
member. This separation will be discussed hereinafter. 
In FIGS. 2 and 3 sheath 24 is shown attached to connector 22, and 
particularly to collar 28. In the embodiment being described, sheath 24 is 
flexible and is substantially cylindrically shaped in cross-section and is 
sized to fit inside collar 28 and substantially abut shoulder 31 whereupon 
it is secured to collar 28 opposite from male fitting member 36. Since 
both sheath 24 and collar 28 are preferably made of plastic, the 
attachment may be made by heating sealing; of course, adhesives or other 
materials or techniques may be employed to secure the sheath to the 
collar. When secured to the collar, the inside space of sheath 24 is in 
communication with bore 29 of the collar. This, of course, provides a 
substantially axial alignment between the sheath and male fitting member 
so that the flexible tubing can be subsequently moved from inside the 
sheath through the connector and the male fitting member and then into the 
patient. 
Through the periphery of sheath 24 is a hole 41. This hole is located near 
the connector and is preferably positioned through the sheath so as to lie 
inwardly spaced in bore 29 of collar 28. At the point where hole 41 is 
positioned, sheath 24 is not secured to collar 28 so that the walls of the 
sheath in the embodiment being described, may be flexed away from the bore 
of the collar to provide access to hole 41. This hole through the sheath 
allows insertion of barrel 19 of the introducer needle therethrough and 
into bore 29 of the collar. In this regard, the hole is sized to 
accommodate the diameter of the needle barrel and is accordingly 
relatively small. The hole is preferably located within the confines of 
the collar to prevent the operator's fingers from inadvertently touching 
the flexible tubing inside the protective sheath during its insertion into 
the patient. 
Other insertion means may be employed in and through sheath 24 for allowing 
the insertion of the introducer needle through the connector of the 
catheter placement unit. For example, an alternate embodiment of this 
insertion means is illustrated in FIG. 4. Underneath hole 41 is a small 
disc 42 of elastomeric material, such as rubber which may be adhered to 
the sheath at the point where the needle puncture is to be made. Disc 42 
may include a slit 44 to allow easy penetration of the introducer needle. 
This type of a puncturable membrane-disc, in addition to allowing needle 
insertion, also provides a liquid-tight seal after the needle is 
withdrawn. When using a puncturable membrane of this type, a pre-formed 
hole in the sheath is optional since the membrane will serve as the path 
through which the needle will pass. 
Catheter placement system 10 is illustrated completely assembled and in the 
venipuncture position in FIG. 5. Connector 22 of the catheter placement 
unit has been attached to the introducer catheter by means of male fitting 
member 36 being inserted into hub 18. Introducer needle barrel 19 has been 
inserted through hole 41 in sheath 24; it is noted that the sheath is 
preferably flexed away from the end of bore 29 in collar 28 so as to 
expose hole 41, and also allow the needle to be inserted concentrically in 
bore 29 and into passage 39 of the male fitting member. Needle barrel 19 
extends completely through hollow tube 15 and projects slightly beyond its 
distal end. With the introducer needle inserted in this assembly, it is 
noted that the tip 45 of hollow flexible tubing 25 is spaced a short 
distance from connector 22. This space is to allow sufficient clearance 
for the introducer needle to be inserted and then subsequently withdrawn 
after it performs its venipuncture purpose. It is also noted that 
protective sheath 24 not only covers the entire length of flexible tubing 
25 but also fitting 26 at the end of the flexible tubing. The extreme end 
46 of the sheath may be sealed shut, but such a seal is merely optional. 
With the components assembled as described, needle tip 20 penetrates the 
skin of patient P and is introduced into a vein V of the patient. During 
this venipuncture, hollow tube 15 of the introducer catheter also is 
introduced into vein V. Once the needle and introducer catheter are in 
proper position in the vein, the introducer needle is withdrawn by 
grasping handle 21 and backing the needle out of the introducer catheter 
and connector of the catheter placement unit through hole 41 in the 
protective sheath. While the introducer needle is being withdrawn, tube 15 
of the introducer catheter remains in position in vein V. When the needle 
is withdrawn, flexible tubing 25 is inserted, tip 45 first, through 
connector 22 and on into the lumen of the introducer catheter. This 
insertion is best seen by referring now to FIG. 6. 
With the introducer needle withdrawn, and preferably discarded, the 
operator grasps sheath 24 with his fingers, designated F, and manipulates 
flexible tubing 25 into bore 29 of collar 28 and then into passage 39 of 
male fitting member 36, through hub 18 and hollow tube 15 of the 
introducer catheter whereupon it exits into vein V of patient P. The 
flexible, pliant nature of the preferred sheath 24 permits ready movement 
and manipulation of the flexible tubing within in an expeditious manner. 
Other non-flexible or semi-flexible sheaths may also be employed as long 
as the flexible tubing within may be manipulated for insertion into the 
patient. Moving the flexible tubing through the catheter placement unit 
while enclosed by the sheath, of course, prevents contamination of the 
flexible tubing which will be introduced directly into the vein of the 
patient. 
When flexible tubing 25, serving as the catheter, is in position in the 
patient, fitting 26 at its end is preferably adapted to fit into cavity 40 
within male fitting member 36. When the flexible tubing is finally 
positioned, sheath 24 is no longer required; accordingly, by applying a 
small amount of pressure, male fitting member 36 is separated from both 
retaining ring 34 and collar 28. This feature is illustrated in FIG. 7. 
Inasmuch as sheath 24 is secured to collar 28, this separation effectively 
removes the sheath and exposes fitting 26 to which a connection may be 
made to an administration set, pressure monitoring device or the like. At 
this stage, the catheter placement unit is thus in its operable condition. 
Flexible, hollow tubing 25 and hollow tube 15 of the introducer catheter 
are preferably made from a bio-compatible material, such as 
polytetrafluoroethylene, and are preferably very flexible so that the 
trauma to the vein or other body tissues of the patient is significantly 
minimized. Hub 18 of the introducer catheter, and the connector components 
of the catheter placement unit are preferably plastic. Sheath 24 is 
preferably a transparent, plastic material generally very pliant and 
sufficiently thin so as to allow the fingers of the operator to virtually 
feel the flexible tubing which is enclosed within the sheath. 
Thus, there has been provided a catheter placement unit, system and method 
of use which allows an introducer needle to be withdrawn after 
venipuncture has been made and which serves as a closed system, i.e., the 
catheter is attached to the venipuncture instrument when venipuncture is 
made so that a subsequent connection of the catheter does not have to be 
made.