Tubing administration set for use in peritoneal dialysis

Apparatus for administering dialysis, including a separable tubing coupling (32). The tubing coupling (32) consists of a hollow cylindrical element (42, 44) insertable into the lumens of the distal and proximal regions of the fluid delivery tube (16), and has a scored circumference at which the coupling can be broken-off by application of an adequate bending force. The device allows rapid and reliable disconnecting of the patient from the dialysis apparatus, without the need for scissors or a knife to be employed.

The present invention relates to improved means for performing manual and 
automatic peritoneal dialysis. More specifically, the invention is 
directed at an efficient and simple means for connecting and disconnecting 
the fluid delivery tube that runs from the dialysis solution to the 
peritoneal cavity of the patient. The invention includes a scored plastic 
coupling connecting proximal and distal segments of the delivery tube 
which can be broken along the scoring to disconnect the tube. 
In the present state of the art, there are two commonly used techniques for 
the treatment of patients who have experienced significant renal failure. 
The traditional therapy has been haemodialysis, where the patient's blood 
is passed through filters that will remove the metabolic products from the 
patient's blood stream. 
The second technique is peritoneal dialysis, where solutions are cycled 
into and out of the peritoneal cavity of the patient and wastes are 
removed with the spent solution. 
Both techniques operate by the principles of diffusion across semipermeable 
membranes. In the case of peritoneal dialysis, the membrane that is used 
is the patient's peritoneal membrane. Although not as efficient as 
haemodialysis, peritoneal dialysis offers several advantages that have 
enhanced its desirability. For example, automated devices have been 
developed that allow a patient to undergo a dialysis treatment at night 
while the patient is asleep. Utilising these automated devices allows the 
patient greater mobility and more free time. 
Peritoneal dialysis can be accomplished in several different modes. In CAPD 
(Continuous Ambulatory Peritoneal Dialysis), the infusion of solution into 
and out of the peritoneal cavity is accomplished while the patient 
functions normally throughout the day. The obvious disadvantages of CAPD 
are the cumbersome devices that must be worn by the patient. Examples of 
CAPD systems are disclosed in U.S. Pat. Nos. 4,747,822 of Peabody and 
4,620,846 of Goldberg. 
Two types of peritoneal dialysis therapies that are particularly suitable 
for use with automated systems are, on the one hand, the IPD-system 
(Intermittent Peritoneal Dialysis) and, on the other hand, the CCPD-system 
(Continuous Cycling Peritoneal Dialysis). In the IPD-system, large volumes 
of dialysis solution (up to 40 liters) are cycled through the patient's 
peritoneal cavity over a period of 4 to 24 hours. In the CCPD-system, the 
dialysis treatment is more or less continuous, with a treatment time of 3 
to 4 hours at night and then, throughout the waking time of the patient a 
single charge of dialysis solution is retained during the day within the 
peritoneal cavity of the patient. There are certain advantages to each of 
these two different therapy techniques. 
In both methods, not only IPD but also CCPD, an automated dialysis 
apparatus operates in generally the same manner. The dialysis solution and 
tubing administration set is integrated with the valving, heating and 
control functions associated with the automated apparatus. In many of the 
systems, pre-measured volumes of dialysis solution are either pumped or 
delivered by gravity flow to a heating station. At the heating station the 
solution is warmed to body temperature in order to prevent the 
uncomfortable sensation of introducing a solution at room-temperature or 
cooler into the peritoneal cavity. The warmed solution is then delivered 
from the dialysis station to the patient's peritoneal cavity via a fluid 
delivery tube which is essentially flexible tubing connected to the end of 
a catheter that enters the patient's peritoneal cavity. After a period of 
time (the "dwell period"), the solution is drained from the patient into a 
receiving container. 
In the IPD-system, a large volume of solution is cycled in this manner 
during a relatively short period of time. Once treatment is completed, the 
patient is unencumbered for at least a few days. A disadvantage is the 
large volume of dialysis solution that must be utilised. Bags containing 
40 liters of solution can be difficult to lift for a patient in a weakened 
condition. 
With CCPD- and CAPD-methods, the same efficaceous results are obtained by 
increasing the dwell time of the dialysis solution within the peritoneal 
cavity. The total volume of solution can therefore be significantly 
reduced. The obvious disadvantage is that there is less "down time" for 
the patient to recover from the treatment. 
The delivery tube in the PD-therapy generally includes a flexible tubing to 
transfer fluid to and from the catheter site, a catheter to enter the 
peritoneal cavity, and a connector between the tubing and the catheter. A 
detachable manual clamp is fitted onto the tubing to occlude the tubing as 
it is being connected to the catheter by means of the connector. Also 
included is a manually actuated permanent clamp to occlude the tubing 
permanently when the dialysis is completed so that the tubing can be 
disconnected from the catheter connector without spilling any of the fluid 
drained from the peritoneal cavity. A wide variety of PD-systems are known 
in the state of the art and are used in a number of different 
applications. 
Upon completion of the CCPD, it is necessary to disconnect the patient from 
the tubing set. This is normally accomplished by occluding the delivery 
tube by closing the permanently attached manual clamp, and then cutting 
through the tubing on the side of the permanently manual clamp away from 
the patient. The permanent manual clamp thereby occludes the delivery tube 
on the patient side in order to prevent any spilling of the drained fluid. 
After the tubing is cut, a clamp on the catheter side is used to occlude 
the catheter. The stub of the tubing is removed from the catheter when the 
PD-system is next changed. A new PD-system is then connected to the 
catheter, the catheter clamp is opened and the process is repeated. The 
cutting of the delivery tube is normally accomplished with a pair of 
scissors or a knife. The PD-therapy is distinguished by the fact that it 
can be carried out by the patients themselves, without the help of a nurse 
or other person, and the scissors or knife must be located so that the 
patient can reach them while still connected to the tubing set. 
Another drawback to a system in which the delivery tube is cut with a knife 
or scissors is that there is no indicator on the delivery tube as to where 
it should be cut. A frequent problem, therefore, is that the patient 
unfortunately cuts the delivery tube on the patient side of the clamp, 
thereby spilling drainage fluid. Even worse, the patient sometimes 
inadvertently cuts the catheter rather than the tubing, thereby requiring 
the removal of the damaged catheter and its replacement with a new 
catheter. 
It is therefore the task of the present invention to solve the problem of 
the prior state of the art in such a manner that an accidental cutting of 
the delivery tube is prevented. 
This problem is solved in accordance with the present invention by 
providing means in the region of the delivery tube so that said delivery 
tube can be separated from the remainder of the tubing. 
The tubing of the delivery tube in accordance with the invention includes a 
plastic coupling toward the tubing end that goes to the catheter in the 
patient's peritoneal cavity. In accordance with a first embodiment, the 
coupling divides the tubing into a segment proximal to the peritoneal 
cavity and a segment distal to the peritoneal cavity, the two segments 
being connected by the coupling. The coupling is a hollow cylindrical 
element, one end of which is inserted into the open end of the distal 
tubing segment and the other end is inserted into the open end of the 
proximal tubing segment. The coupling is retained in the tubing by a 
friction fit or sealing-in with a solvent. An annular lip around the 
circumference of the coupling at or near its centre expediently serves as 
a stop for the ends of the tubing. The coupling is scored around its 
circumference near the annular lip. 
When the PD-procedure is completed, and the delivery tube is suitably 
clamped, the coupling is easily broken at its nominal breaking-off site by 
strong bending. In this way, neither scissors nor knife is needed, so that 
there is no danger that the delivery tube will be cut through on the wrong 
side of the clamp or that the catheter itself will be inadvertently cut 
through. 
In an additional advantageous further development of the invention, a 
Y-shaped connector piece is used for connection of the tubing. The first 
tube from the Y-piece goes to the patient, the second tube goes to a bag 
filled with fresh flushing solution and the third tube goes to a waste 
discharge tube. According to this second example of embodiment, the 
nominal breaking-off site is located around the outer circumference of the 
Y-branch which is connected to the first tube.

FIG. 1 shows a region 12 of a tubing set for use with an automated 
peritoneal dialysis apparatus (not shown). The tubing set portion 12 
includes a fluid supply tube 14, a fluid delivery tube 16 for connection 
to a peritoneal catheter, a drain tube 18 connected to a drain bag, and a 
Y-shaped connector for connecting the fluid supply tube 14, fluid delivery 
tube 16 and drain tube 18. At the end of the fluid delivery tube 16 is a 
connector 22 for connecting the fluid delivery tube to a peritoneal 
catheter. At the end of the fluid supply tube 14 is another connector 24 
for connecting the fluid tube to a set (not depicted) of fluid containers. 
The fluid delivery tube 16 includes a tube section 28 proximal to the 
patient's peritoneal cavity, a tube section 30 distal to the patient's 
peritoneal cavity and a tubing coupling 32 connecting the distal and 
proximal sections in the manner to be described further on. The fluid 
delivery tube 16 also includes a detachable manual clamp 34 on the distal 
tubing section 30 and a permanent manual clamp 36 on the proximal tubing 
section 28. The tubing is ordinary flexible plastic tubing for medical 
purposes. The detachable manual clamp 34 is an elongated open-ended 
pretensioned member with a pair of clamps on its inner surface that clamps 
onto the tube when the member is squeezed. An edge on one of the open ends 
snaps into a set of serrations on the other open end to hold the clamps 
onto the tubing, thereby partially or entirely occluding the tubing. The 
edge on one of the open ends can be disengaged from the serrations in the 
other open end by distorting the other open end away from the edge on the 
first open end. Clamps of this type are well known in the state of the 
art, and will not be further described here. 
The permanent manual clamp 36 on the proximal tubing section 28 is also of 
a type that is well known in the state of the art. Briefly, it includes 
two hinged halves, the first of which can be slid on and snapped over the 
tubing and the second of which mates with the first by folding onto the 
first through the hinge. The second half has a protrusion which compresses 
and thereby completely occludes the tubing when it is folded over the 
first half. The first half includes a pair of hooks that snap into a pair 
of matching slots in the second half, thus permanently and entirely 
occluding the tubing. 
The tubing coupling 32 is better recognised in FIG. 2, where it is shown 
attached to the proximal tubing section 28 and the distal tubing section 
30, and in FIG. 3 it is depicted detached from the tubing. The tubing 
coupling 32 includes a distal hollow cylinder 42 and a proximal hollow 
cylinder 44. Each of these cylinders is an elongated component with a 
central bore 46 and 48, respectively. The outside diameter of the hollow 
cylinders 42 and 44 tapers to a smaller diameter at each end. Preferably 
the maximum outside diameters are slightly greater than the inside 
diameter of the tubing into which they are inserted, so that the hollow 
cylinders can be pressed into the tubing to achieve a snug and watertight 
friction fit between the tubing coupling 32 and the tubing. The inside 
diameter of the hollow cylinders is as large as possible so that the fluid 
flow is not unduly restricted through the coupling, but not so large that 
the wall thickness of the hollow cylinders is so small that the tubing 
coupling 32 breaks under normal operating conditions. It has been found 
that, for use with polyvinyl chloride (PVC) medical-grade plastic tubing 
and a coupling formed from polycarbonate, these conditions can be met by 
having an inside diameter of 4 millimeters and a maximum outside diameter 
of 6.15 millimeters and a minimum outside diameter at both ends of 5.8 
millimeters. 
Positioned between the distal hollow cylinder 42 and the proximal hollow 
cylinder 44 of the tubing coupling 32, there is a raised annular stop 50 
extending around the circumference of the hollow cylinders 42 and 44. The 
annular stop 50 acts as a detent for the distal tubing section 30 and 
proximal tubing section 28, so that each of them can be pushed onto the 
coupling to an appropriate extent to achieve a secure and watertight 
connection. In the preferred embodiment, each of the hollow cylinders 42 
and 44 has a length of at least 25.4 millimeters and the annular stop has 
an outside diameter of 7.9 millimeters. 
The proximal hollow cylinder 44 of the tubing coupling 32 is scored 58 
around its outer circumference at a location adjacent to the raised 
annular stop 50, so that the coupling can be broken in the manner to be 
described further on. It has been found that, for a coupling wall 
thickness of 1 millimeter, a scoring depth of approximately 0.63 
millimeter is sufficient to allow the coupling to be broken easily, 
without weakening the coupling to such an extent that it breaks 
accidentally. The scoring 58 may be on the distal hollow cylinder 42 
rather than on the proximal hollow cylinder 44. In either position, the 
scoring 58 is preferably located adjacent to the raised annular stop 50, 
so that neither tube overlaps the breaking-off site appreciably and 
prevent the coupling from separating when it is broken. 
In another advantageous form of embodiment of the invention, as depicted in 
FIG. 4, the means for separation is located in the region adjacent to the 
branching site 59 of the branch 69 of the Y-shaped tubing connector 60 
which also possesses two other branches 67 and 68. The branches 67-69 are, 
as may be seen from FIG. 4, are connected to the tubing pieces 14, 18 and 
16 respectively. In this arrangement, the nominal breaking-off site is 
indicated at 61. Said breaking-off site 61, similarly to the tubing 
coupling 32, possesses a scoring 64 which can extend around the entire 
circumference of the Y-branch 69. Because of the separating means on 
branch 69 of the Y-shaped tube connector 60, the tubing portion 16 to be 
broken-off can be readily and reliably separated from the Y-shaped tube 
connector 60. 
As already indicated previously, the tubing coupling and the Y-shaped tube 
connector 32 may be made from a synthetic plastics material, in particular 
polycarbonate, and may be fabricated by injection moulding. Other 
materials and fabrication methods will be apparent to persons skilled in 
the art. 
In operation, the tubing set 12 is positioned so that the fluid tube 14 is 
connected to one or more fluid containers (not depicted) which contain a 
solution suitable for the PD-procedure. The drain container 20 is suitably 
located at a position generally lower than the patient's peritoneal 
cavity. The fluid delivery tube 16 is connected to the catheter entering 
the patient's peritoneal cavity. The manual releasing clamps 34 and 33 on 
the fluid delivery tube 16 and on the fluid tube 14 respectively are 
opened, the manual releasing clamp 35 on the drain tube 18 is released so 
that the spent fluid is usually discharged under the influence of gravity. 
The clamp 35 is then closed and the clamp 34 on the fluid delivery tube 16 
is opened so that fresh PD-fluid from the fluid container bags (not 
depicted) can flow through the fluid tube 14 and the fluid delivery tube 
16 into the peritoneal cavity. Following this the manual releasing clamp 
34 and the permanent manual clamp 36 are closed to occlude the fluid 
delivery tube 16 completely. The fluid delivery tube 16 is then separated 
into the proximal section 28 and distal section 30 by breaking the tubing 
coupling 32 in accordance with the first form of embodiment. The breaking 
of the tubing coupling 32 is accomplished by grasping each end and bending 
it so that it breaks cleanly along the scoring 38. The proximal tubing 
section 28 can be removed from the catheter when the system is being 
changed over. 
In accordance with another form of embodiment, the Y-shaped piece is 
grasped on the one side by the two branches 67 and 68 and on the other 
side by the branch 69 and then bent in such a way that it breaks off at 
the nominal breaking-off site, thus freeing the branch 69. Because of this 
separating operation of the fluid delivery tube 16 by the breaking of the 
tubing coupling 32 or of the Y-shaped piece, the effect is achieved that 
there is no need for either a knife or for scissors or for any other tool 
at all to effect this separating operation. 
Moreover, this tubing arrangement 12 for separating the fluid delivery tube 
16 ensures that the separation will occur at the tubing coupling 32 or at 
the Y-shaped piece 60 rather than on the wrong side of the clamp or some 
other incorrect location, since the permanent manual clamp 36 is installed 
in the position on the working side between the nominal breaking-off site 
58 or 64 and the connector 22 on the patient side. In conclusion, it can 
be stated that this results in a simple, inexpensive and very safe and 
reliable system. Although the tubing coupling 32 and the Y-shaped tubing 
connector are described in relation to peritoneal dialysis, it will be 
apparent that the tubing coupling 32 may be used for other types of 
dialysis and for other medical and non-medical applications.