Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-03-19
2002-09-10
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S502000, C604S527000
Reexamination Certificate
active
06447488
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the dialysis of blood in general, and more particularly to apparatus and methods for use in the same.
BACKGROUND OF THE INVENTION
A healthy kidney removes toxic wastes and excess water from the blood. In End Stage Renal Disease (“ESRD”), or chronic kidney failure, the kidneys progressively stop performing these essential functions over a long period of time. When the kidneys fail, a patient dies within a short period of time unless that patient receives dialysis treatment for the rest of that patient's life or undergoes transplantation of a healthy, normal kidney. Since relatively few kidneys are currently available for transplantation, the overwhelming majority of patients with ESRD receive dialysis treatment.
Hemodialysis therapy is an extracorporeal (i.e., outside the body) process which removes toxins and water from a patient's blood. A hemodialysis machine pumps blood from the patient, through a dialyzer, and then back to the patient. The dialyzer removes the toxins and water from the blood by a membrane diffusion process. Typically, a patient with chronic kidney disease requires hemodialysis three times per week, for 3-6 hours per session. Removing blood from the body requires a vascular access to the patient's blood system.
One common method for accessing a patient's blood system for hemodialysis involves the use of a percutaneous catheter assembly. The percutaneous catheter assembly is inserted into a major vein, such as the femoral, subclavian or jugular vein. For long term maintenance dialysis, the jugular vein is generally the preferred insertion site. The catheter assembly is percutaneous, with one end external to the body and the other end dwelling in either the superior vena cava or the right atrium of the heart. The external portion of the catheter assembly has connectors permitting attachment of blood lines leading to and from the hemodialysis machine.
FIGS. 1 and 2
show the traditional manner of positioning a percutaneous catheter assembly
5
relative to the body. More particularly, percutaneous catheter assembly
5
generally comprises a catheter portion
10
comprising a dual-lumen catheter element
15
, and a connector portion
20
comprising an extracorporeal connector element
25
. The catheter assembly's extracorporeal connector element
25
is disposed against the chest
30
of the patient, and the distal end
35
of catheter element
15
is passed into the patient's internal jugular vein
40
(
FIG. 2
) and then down into the patient's superior vena cava
45
. More particularly, the distal end
35
of catheter element
15
is positioned within the patient's superior vena cava
45
such that the mouth
50
of suction line
55
, and the mouth
60
of return line
65
, are both located between the patient's right atrium
70
and the patient's left subclavia vein
75
and right subclavia vein
80
. Alternatively, the distal end
35
of catheter element
15
may be positioned so that mouth
50
of suction line
55
, and mouth
60
of return line
65
, are located within the patient's right atrium
70
. The percutaneous catheter assembly
5
is then left in this position relative to the body, waiting to be used during an active dialysis session.
When hemodialysis is to be performed on the patient, the catheter assembly's extracorporeal connector element
25
is appropriately connected to a dialysis machine (not shown), i.e., suction line
55
is connected to the input port (i.e., the suction port) of the dialysis machine, and return line
65
is connected to the output port (i.e., the return port) of the dialysis machine. The dialysis machine is then activated (i.e., the dialysis machine's blood pump is turned on and the flow rate set), whereupon the dialysis machine will withdraw relatively “dirty” blood from the patient through suction line
55
and return relatively “clean” blood to the patient through return line
65
.
It has also been proposed to use a subcutaneous port and catheter assembly to provide vascular access for hemodialysis.
More particularly, a subcutaneous port and catheter assembly
82
is shown in
FIGS. 3-5
. Looking first at
FIG. 3
, subcutaneous port and catheter assembly
82
generally comprises a connector portion
84
comprising a subcutaneous port element
86
, and the aforementioned catheter portion
10
comprising the dual-lumen catheter element
15
. As noted above, the catheter element
15
in turn comprises the suction line
55
and the return line
65
. Subcutaneous port element
86
includes a needle port
88
which is connected to suction line
55
, and a needle port
90
which is connected to return line
65
. The distal end of suction line
55
terminates in the aforementioned mouth
50
, and the distal end of return line
65
terminates in the aforementioned mouth
60
.
FIGS. 4 and 5
show subcutaneous port and catheter assembly
82
positioned within the body. More particularly, the assembly's port element
86
is disposed under the skin of the patient (e.g., in the chest area of the patient), and the assembly's catheter element
15
is passed into the patient's internal jugular vein
40
and then down into the patient's superior vena cava
45
. The distal end of the assembly's catheter element
15
may be positioned within the patient's superior vena cava
45
such that mouth
50
of suction line
55
, and mouth
60
of return line
65
, are both located approximately between the patient's right atrium
70
and the patient's left subclavia vein
75
and right subclavia vein
80
. Alternatively, the distal end of catheter element
15
may be positioned so that mouth
50
of suction line
55
, and mouth
60
of return line
65
, are located within the patient's right atrium
70
. The subcutaneous port and catheter assembly
82
is then left in this position within the body, waiting to be used during an active dialysis session.
When hemodialysis is to be performed on the patient, the assembly's subcutaneous port element
86
is appropriately connected to a dialysis machine, i.e., needle port
88
is connected to the input port (i.e., the suction port) of the dialysis machine with an appropriate percutaneous needle (not shown), and the assembly's needle port
90
is connected to the output port (i.e., the return port) of the dialysis machine with an appropriate percutaneous needle (not shown). The dialysis machine is then activated, whereupon it will withdraw relatively “dirty” blood from the patient through suction line
55
and return relatively “clean” blood to the patient through return line
65
.
It will be appreciated that both percutaneous catheter assembly
5
(
FIGS. 1 and 2
) and subcutaneous port and catheter assembly
82
(
FIGS. 3-5
) comprise the catheter portion
10
, which in turn comprises the dual-lumen catheter element
15
, with the distal end of the catheter element normally dwelling in the patient's vascular system.
Inasmuch as a substantial portion of catheter element
15
dwells in the patient's vascular system (e.g., within internal jugular vein
40
and superior vena cava
45
), it is desirable for the catheter element to have the smallest possible outside diameter so as to minimize interference with normal blood flow. At the same time, however, it is also desirable for the catheter element to have the largest possible inside diameter so that maximum dialysis blood flow can be achieved. Thus, from the standpoint of blood flow alone, it is desirable for the catheter element to have the thinnest possible wall thickness.
Unfortunately, however, other considerations also come into effect. For one thing, it is also important that the catheter element have the highest possible burst strength so that it will not fail when passing blood under pressure. In addition, it is also important that the catheter element be able to withstand high negative pressures without collapsing, so that blood can be withdrawn from the body at a r
Estabrook Brian K.
Martins Harold M.
Prosl Frank R.
Smith Paul J.
Biolink Corporation
Kennedy Sharon
Pandiscio & Pandiscio
LandOfFree
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