Surgery – Blood drawn and replaced or treated and returned to body – Constituent removed from blood and remainder returned to body
Reexamination Certificate
1999-11-23
2003-09-16
Sykes, Angela D. (Department: 3762)
Surgery
Blood drawn and replaced or treated and returned to body
Constituent removed from blood and remainder returned to body
C604S004010, C604S093010, C604S523000, C604S264000
Reexamination Certificate
active
06620118
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
1. End Stage Renal Disease
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. Because few kidneys are 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 principle. 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. This vascular access can be accomplished by surgically modifying the patient's own blood vessels or attaching an artificial device to the vessels. If the vascular access site is entirely beneath the skin, the skin and the vascular site must be punctured by a needle attached to blood tubing. This needle and tubing is typically called a “set”.
This vascular access must remain patent (i.e., unblocked) and free from medical complications to enable dialysis to take place. It must allow blood to flow to the machine at a sufficiently high rate to permit dialysis to take place efficiently. And it should allow the patient to carry on a normal life.
2. Hemodialysis Vascular Access
A. Vascular Access—A Major Medical Need
Vascular access is widely called the “Achilles heel of dialysis” because high morbidity and mortality among dialysis patients is associated with complications of vascular access. Vascular access complications are believed to be the single greatest cause of morbidity and to account for approximately one-fourth of all admissions and hospitalization days in the hemodialysis population.
The financial impact to the health care system of these vascular access problems is enormous. By way of illustration, an analysis of the International
Classification of Diseases (ICD-9) codes for the U.S. for 1993 showed over 91,000 procedures for the three codes dealing with (1) “Revise Renal Dialysis Shunt”, (2) “Remove Renal Dialysis Shunt”, and (3) “Complications of Renal Dialysis Device”. More than 450,000 days of hospital stay days were involved for just these three codes alone. Clearly, the complications of the current methods of vascular access are costly, whether measured individually for a single event or aggregately for the whole patient population.
Thus, the need for improved vascular access is great.
B. Three Major Methods of Vascular Access
The major advances in vascular access for hemodialysis are listed below:
Year
Scribner shunt
1959
AV (arterio-venous) fistula
1966
Polytetrafluoroethylene (PTFE) graft
1977
Percutaneous catheter assembly
1983
implanted in jugular vein
1. The Scribner Shunt
The Scribner shunt was the breakthrough percutaneous device which enabled patients with chronic kidney disease to be treated with the primitive, already-existing hemodialysis machines. The Scribner shunt suffered from major infection and clotting problems and is no longer used.
2. The AV (Arterio-Venous) Fistula
The first of the three major methods of permanent vascular access currently in use is the native AV (arterio-venous) fistula. The AV fistula is a surgical construct connecting a patient's major artery to a major vein subcutaneously in the arm. With this new blood flow path, most blood will bypass the high flow resistance of the downstream capillary bed, thereby producing a dramatic increase in the blood flow rate through the fistula. Furthermore, although it is not medically feasible to repeatedly puncture an artery, formation of the fistula “arterializes” the vein. The arterialized vein can be punctured repeatedly, and the high blood flow permits high efficiency hemodialysis to occur. Two fistula needles, connected to blood tubing leading to and from the hemodialysis machine, are used to puncture the skin to gain access to the arterialized vein. Blood is withdrawn from the arterial side of the vein, passes through the machine, where it is cleansed, and returns to the venous side of the access.
3. Polytetrafluoroethylene (PTFE) Graft
The PTFE graft is an artificial, tubular, vascular graft made from polytetrafluoroethylene, a Teflon-type material. Implanted in a surgical procedure, the graft
5
(see
FIG. 1
) connects an artery
10
to a vein
15
in the arm, forming a bypass which can be punctured by fistula needle sets in the same way a normal AV fistula is accessed.
4. Percutaneous Catheter Assembly Implanted in Jugular Vein
The third method of vascular access for hemodialysis is a central venous percutaneous catheter assembly inserted into a major vein, such as the femoral, subclavian or jugular vein. For long term maintenance dialysis, the jugular vein is the preferred insertion site. These catheter assemblies are 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 these catheter assemblies has connectors permitting attachment of blood sets leading to and from the hemodialysis machine.
FIGS. 2 and 3
show the traditional manner of positioning a central venous percutaneous catheter assembly
20
within the body. More particularly, percutaneous catheter assembly
20
generally comprises a catheter portion
21
comprising a catheter element
22
, and a connector portion
24
comprising an extracorporeal connector element
25
. The assembly's extracorporeal connector element
25
is disposed against the chest
30
of the patient, and the distal end
35
of catheter element
22
is passed into the patient's internal jugular vein
40
(
FIG. 3
) and then down into the patient's superior vena cava
45
. More particularly, the distal end
35
of catheter element
22
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
. In this respect it is to be appreciated that, since mouth
60
of return line
65
is located distal to mouth
50
of suction line
55
, mouth
60
of return line
65
will be located closer to right atrium
70
than is mouth
50
of suction line
55
. Thus, mouth
60
of return line
65
is located downstream of mouth
50
of suction line
55
. The percutaneous catheter assembly
20
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 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
. In this respect it is to be appreciated that, inasmuch as mouth
50
of suction line
55
is positioned upstream from mouth
60
of ret
Estabrook Brian K.
Prosl Frank R.
Biolink Corporation
Deak Leslie R
Pandiscio & Pandiscio, P.C
Sykes Angela D.
LandOfFree
Apparatus and method for the dialysis of blood does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for the dialysis of blood, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for the dialysis of blood will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3093278