Catheter or cannula system

A catheter or cannula (2) which includes a press or pinch point (18) which may be resiliently deformed to prevent flow of blood or other body fluids during insertion of the catheter or cannula tube (10) or it may be part of the boss (11) of the catheter or cannula (2). One or more protrusions or buttons (20) may be integrally moulded to the press or pinch point (18) to assist with the application of pressure to the press or pinch point (18) to prevent fluid flow. Wings (14) extending from the sides of the cannula or catheter (2) may provide support and be hinged to enable compression of the press or pinch point (18). The cathether or cannula tube (10) is of a size to fit over a hypodermic needle (5) of a trocar (1) inserted into the catheter or cannula (2).

TECHNICAL FIELD 
This invention relates to an improvement to systems which use an artificial 
tube for supply to or extraction of fluids from a human or animal body. 
BACKGROUND ART 
The insertion of a tube into a human or animal in many cases requires a 
hole to be pierced through the skin. For this purpose a device known as a 
trocar, a catheter or a cannula may be used. A trocar is a sharp pointed 
instrument adapted to punch the wall of the body. The trocar may have a 
catheter or cannula mounted onto it and upon removal of it from the 
catheter or cannula fluid may be extracted. A catheter is a tubular 
flexible instrument passed into a body cavity or channel for withdrawal of 
fluids from or introduction of fluids into the body cavity or channel. A 
cannula is for inserting into a duct or cavity in a body. During its 
insertion its lumen may be occupied by a stylet or trocar. A stylet is a 
wire adapted to run through a catheter or cannula to render it stiff or to 
remove debris from its lumen. 
One specialized form of trocar or stylet is a hypodermic needle having a 
splash back with a window so that during insertion when blood is seen in 
the window it is known that a vein or artery has been pierced. 
Generally in this specification and claims the word cannula will be used to 
describe either a catheter or cannula and trocar will be used to define a 
trocar, stylet or splash back. 
Generally a catheter or cannula with a stylet or trocar or combination of 
these is used as an artificially inserted tube into a human or animal body 
either for the delivery of fluids into the body or the removal of fluids 
from the body. In one method a catheter or cannula assembly is inserted 
into a vein of an animal or human and the trocar or stylet is removed to 
leave the cannula or catheter in place. At the time of removal of the 
catheter or cannula there can be a problem with loss of blood and perhaps 
of more concern a danger with infection by blood or body fluid borne 
diseases. In the past there has been no reasonable solution to prevent 
this loss of blood. 
It is the object of this invention to provide an arrangement by which the 
loss of blood or other body fluids is able to be restricted during the 
process of insertion of an artificial tube such as a catheter or cannula 
assembly into a human or animal body. 
DISCLOSURE OF THE INVENTION 
In one form the invention is said to reside in a catheter or cannula of the 
type to be mounted on to a trocar, the catheter or cannula incorporating a 
press or pinch point which is adapted to be resiliently deformed by 
externally applied pressure by at least one finger of a person during the 
insertion of the catheter or cannula tube and trocar assembly into a 
patient and removal of the trocar so as to prevent a flow of fluid through 
the catheter or cannula during the insertion and removal, wherein the 
catheter or cannula is of a type including a boss and a catheter or 
cannula tube and the portion which is adapted to be resiliently deformed 
is part of the boss. 
The press point may be associated with the catheter or cannula assembly or 
may be as an attachment which can be fastened onto a catheter or cannula 
assembly. 
It will be seen that generally by this invention, that the press point can 
be used during the insertion of the catheter or cannula assembly and 
during removal of a trocar or stylet used to make the catheter or cannula 
rigid during insertion to stop blood flow until a suitable connection has 
been made to the catheter or cannula for whatever purpose. When in the 
non-pinched state the pinch point of course does not provide any 
restriction to the insertion of the hypodermic needle of the stylet, 
trocar or splash back. 
In an alternative form the invention may be said to reside in a catheter or 
cannula including a boss and a catheter or cannula tube, the boss 
including a first portion into which the catheter or cannula tube is 
mounted and a connection portion which enables the catheter or cannula to 
be connected to another item, characterised by a press or pinch point 
associated with the boss between the first portion and the connector 
portion, the press or pinch point being adapted to be pinched by 
externally applied pressure to restrict flow through the catheter or 
cannula during the insertion of the catheter or cannula into a patient, 
wherein the first portion and the connector portion are connected by a 
frame arrangement and the press or pinch point is included on a flexible 
rubber or plastics material tube received into the frame arrangement 
between the first portion and the connector portion and sealingly engaging 
the first portion and the connector portions respectively. 
The catheter or cannula may generally be of a type including a boss, a tube 
and a connecting portion. The at least one portion which is adapted to be 
resiliently deformed may be at the base of the tube adjacent the boss, or 
alternatively the portion may be included as part of the boss or may be 
between the boss and the connecting portion. 
This resiliently deformable portion of the catheter or cannula may be made 
from a flexible or elastomeric or plastics material such as silicone 
rubber. 
Alternatively the portion of the catheter or cannula which is adapted to be 
resiliently deformed can be an adaptor piece which can be fitted to an 
existing catheter or cannula by the use of known types of medical 
connectors for provision of a pinch point onto such an item. 
In an alternative form the invention may be said to reside in an adaptor 
piece for a catheter or cannula, the adaptor piece comprising a first end 
portion onto which the catheter or cannula may be mounted and a connection 
end portion to enable the adaptor piece to be connected to another item, 
characterised by a press or pinch point being between the first end 
portion and the connector end portion, wherein the first end portion and 
the connector end portion are connected by a frame arrangement and the 
press or pinch point is included on a flexible rubber or plastics material 
tube received into the frame arrangement between the first end portion and 
the connector end portion and sealingly engaging the first end portion and 
the connector end portion respectively. 
The pinch point may be a soft flexible plastics material or rubber portion. 
The entire boss may be made of a soft flexible rubber or plastics material 
and be adapted to be resiliently deformed to provide the pinch point. 
Alternatively the first portion and the connector portion may be connected 
by a frame assembly with the pinch portion being a soft flexible rubber or 
plastics material tube received into the frame assembly between the first 
portion and the connector portion and sealingly engaging the first portion 
and the connector portions respectively. The pinch portion may comprise 
merely a tube portion or a tube with one or two projections or buttons 
extending from it to enable more positive compression of the tube and so 
as to ensure that the fingers of a user are well away from the point of 
the stylet, trocar or splash back. 
In an alternative embodiment the pinch portion may include a more positive 
action arrangement obtained from valve pieces which can be squeezed 
together to more positively close off the flow path. Such valve pieces may 
be spring loaded and biased towards a valve open position so that upon 
release of the pinch portion, the tube will open again for transfer of 
fluids into or out of the body. When in the open position the stylet or 
trocar or hypodermic needle may be inserted between the valve pieces. 
The catheter or cannula arrangement of the present invention may include 
wings extending from the sides of the catheter or cannula to bear against 
the body of a person or animal into which the catheter or cannula is being 
inserted to provide a stable operating surface for the activation of the 
press point. In one embodiment the wings may be hinged on hinge axes 
aligned with the length of the catheter or cannula and may be hinged to 
bear against the pinch point and resiliently deform the press point. 
The artificial tube, catheter or cannula according to this invention may be 
used to enable closing off of blood flow during insertion of an 
intravenous cannula. Such an intravenous catheter or cannula may be used 
for an intravenous drip, anaesthetic supply, saline drip, addition of 
blood expanders or pharmaceuticals or may be used for such things as 
urinary catheters, wound drains, naso-gastric tubes or naso-oral-gastric 
tubes or any other tube through which fluids may flow. 
It may be particularly noted that the present application may have 
veterinary applications as well as applications with the human body. 
This then generally describes the invention but to assist with 
understanding the invention reference will now be made to the accompanying 
drawings which show preferred embodiments of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION 
Now looking more closely at the drawings and in particular the embodiment 
shown in FIGS. 1 to 3 the cannula assembly of this embodiment comprises a 
trocar generally shown as 1 inserted into a cannula generally shown as 2. 
The trocar comprises a hypodermic needle 5 mounted into a base 6. The base 
6 includes a translucent or transparent window portion 7. 
The cannula includes a cannula tube 10 generally of a plastics material and 
of a size to just fit over the hypodermic needle 5 of the trocar 1. The 
cannula tube 10 is fitted into a boss 11 on the cannula body 13 by means 
of a conical stainless steel clamping ring 12. The body 13 of the cannula 
includes wings 14 extending out to each side of the body. The body 13 
terminates in a connecting portion 16 into which some item of medical 
equipment such as an intravenous drip tube connector may be inserted. The 
body includes within it a resilient tube 18 with an aperture 19 
therethrough large enough for insertion therethrough of the hypodermic 
needle 5. The tube portion 18 includes a button 20 integrally moulded into 
it extending through an aperture 21 in the body 13. When the hypodermic 
needle 5 of the trocar 1 is not inserted into the cannula 2 then pressure 
on the button 20 can close off the flow path through the cannula defined 
by the tube 18. 
In use therefore with the cannula and trocar assembly joined together the 
hypodermic needle is inserted into the body of a patient and during 
insertion observation of the window portion 7 is made so that when blood 
is seen it will be realised that a vein has been located. During insertion 
the cannula and trocar are held together by the finger grips 22 and 23. 
The cannula is then held in place by means of fingers on the wings 14 and 
finger grip 23 thumb grip 22 while withdrawing the trocar from the 
assembly and maintaining pressure on the button 20 until the needle 5 has 
been removed and the pressure on the button 20 closes off the flow path 
through the cannula. A suitable item of medical equipment such as an 
intravenous drip tube connector is then connected to the connecting 
portion 16. Adhesive tape may be taped over the wings 14 onto the body of 
the patient to hold the cannula in place. 
The embodiment shown in FIGS. 4A to 4C comprises a catheter 31 and a trocar 
30. The trocar includes a hypodermic needle 32 mounted into the base 33 of 
the trocar 30. The boss 34 of the cannula is comprised of flexible 
plastics material so that as shown in FIG. 4B as the needle 32 is removed 
the boss 34 can be squeezed with the fingers of one hand until shown in 
FIG. 4C the needle 32 is completely removed and the flow path through the 
cannula is closed off. 
In the embodiment shown in FIGS. 5A to 5F the trocar 40 includes a 
hypodermic needle 41 mounted into a base 42 which includes a window 43. 
The cannula part as particularly seen in FIG. 5F comprises a cannula tube 
45 mounted into a boss 46 the boss 46 has a strap member 47 extending to a 
connecting portion 48 with a flexible elastomeric tube 49 extending 
between the boss and the connecting portion and sealably engaging to each 
of these. 
As can particularly be seen in FIGS. 5C and 5D as the hypodermic needle 41 
is withdrawn from the cannula the flexible plastics tube 49 can be 
compressed until it completely closes off the flow path through the 
cannula until a suitable item of medical equipment has been connected. 
FIG. 6A and 6B show two views of an alternative embodiment of cannula 
according to this invention. In this embodiment the portion of the cannula 
which can be squeezed to close off the flow path includes part of the 
cannula tube 51 which can be compressed at the portion 52 where it mounts 
into the boss 53. In this embodiment the boss 53 can be made from a rigid 
plastics material. 
FIGS. 7, 8 and 9 show views of alternative embodiments of cannula adaptors 
according to this invention which can be connected into existing cannulas 
by means of connectors 61 and 62 at each end of the body 60. The body 
includes a portion 64 which can be squeezed as in FIG. 7. FIG. 8 includes 
a portion 65 which has a button which can be pressed to close off the flow 
path. The cross section shown in FIG. 9 includes two buttons 66 which can 
be squeezed together to close off the flow path. 
FIGS. 10, 11 and 12 show an alternative embodiment of a cannula according 
to this invention. 
In this embodiment the cannula 70 includes a boss 71 and a frame assembly 
72 and 74 connected to a connection portion 73. Between the boss 71 and 
the connection portion 73 is a flexible tube 75 which is adapted to be 
compressed to close off the flow path. The frame portion 74 includes wings 
76 and 77 which are hinged to the frame portion 74 by means of integral 
hinges 78. 
When it is desired to close off the flow path rather than squeezing the 
tube 75 directly the wings 76 and 77 may be hinged about the hinges 78 on 
the frame portion 74 so that the protuberances 79 on each wing actually 
compress the tube 75 to close it off. 
By this means a more even pressure may be applied to the tube 75. 
It will be realised that other embodiments of flexible tube as shown in the 
various embodiments of this invention may be used and rather than being of 
an elastic material the tube may include other means by which deformation 
may occur to close off the flow path. Such other means may include a 
helical or coiled spring which can be deformed to close off the flow path. 
Throughout this specification and the claims that follow unless the context 
requires otherwise, the words `comprise` and `include` and variations such 
as `comprising` and `including` will be understood to imply the inclusion 
of a stated integer or group of integers but not the exclusion of any 
other integer or group of integers.