Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to an atraumatic valving mechanism for
operation with a blood passageway of a blood access device and the present
application is divided out of copending Canadian patent application
No. 379,272 filed June 8, 1981.
There are a number of situations in which it is necessary to
provide for fluid communication with the vascular system. For example,
patients suffering from kidney failure require the dialysis of their blood
by means external from the body. Blood containing toxic substances, such
as urea, uric acid, creatine, phosphorus and calcium, must be removed from
the blood system, treated and then returned to the patient. Patients
requiring such blood dialysis need treatment at least two or three times
per week. Patients suffering from hypoalimentation require a device for
providing access to the body's vascular sys~em on at least a daily basis.
One prior method of providing fluid communication with the
vascular sys~em involved the insertion of a needle into an artery from which
blood to be treated was ~aken~ and the insertion of a needle into a patient's
vein or blood return. Such a method proved unsatisfactory due to the
difficulty in providing for the healing of the artery upon removal of the
needle and the ~rauma produced by the repeated needle insertions. Such short-
comings led to the development of external, and later~ internal shunts. An
external shunt involves the insertion of tubes, such as those made of Teflon
(trade mark), into an artery and an adjacent vein in a limb and providing an
external communication or shunt between the tubes, which extends from the body
of the patient, The shunt between the tubes is required in order to provide
flow through the tubes during that period of time that access is not required
for blood treatment, Were such circulating blood flow not provided, a blood
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clot or thrombus could form, as would be the case if the tubes were simply
capped, creating a static blood volume when the tubes were not in use.
Dialysis, for example, is accomplished by connecting the arterial and venous
tubing to a suitable dialysis unit. Such an external shunt configuration
traumatizes the skin adjacent the Teflon tubes and a path is provided through
the skin for infection to enter the patient's body. Furthermore, even with
external shunts, blood clots sometimes form within the tubes and create a
health hazard to the patient.
The disadvantages of external shunts led to the development of
the internal shunt. An internal shunt is performed by joining, within a
body~ openings between an artery and an adjacent vein. The pressure in the
artery being substantially grea~er than that in the vein causes the vein to
become distended, forming a fistula. One or two needles are then inserted
into the fistula in order to achieve communication with the patient's vascular
system. The patient suffers major discomfort and pain each time the needles
are inserted into the fistula~ MoreoverJ the continuous insertions into the
fistula cause it to become layered with scar tissue which ultimately
prevents further intrusion, thus requiring the formation of another shunt.
Both the internal and external shunts increase the loading on the
patient's heart due to the joining of the artery to a vein having a lower
pressure~ thereby lowering the artery's pressure~ and requiring the heart to
attempt to regain the original arterial blood pressure. Further~ in many
cases, the reduced circulation in the distal portion of the limb wherein the
shunt is effected impairs the adequate removal of waste products from the
muscles and other tissues resulting in weakness of the limb.
An object of the present invention is to provide an atraumatic valve
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for a blood access device. Other objects and advantages o~ this invention
will become apparent upon a reading of the entire specification, including
the drawings and claims.
According to one aspect of the invention there is provided an
atraumatic valving mechanism for operation within a blood passageway of a
blood access device having an ext~rnal rim, said blood passageway adapted to
connect a blood vessel within a body to the body exterior, said valving
mechanism comprising:
a plugging means for sealing said blood passageway;
a retaining cap and a retaining cap ring for engaging therewith
for securing said retaining cap to said blood access device~ said retaining
cap having an aperture and a restraining shoulder for slidably engaging said
blood access device external rim and forcing said retaining cap and blood
access device together upon engaging said retaining cap and cap retaining
ring.
According to another aspect of the invention there is provided
an atraumatic valving mechanism for opera~ion within a blood passageway of a
blood access device, said bIood passageway adapted to connect a blood
vessel within a body to th0 body exterior, said valving mechanism comprising:
a retaining cap and a retaining cap ring for engaging therewith
securing said retaining cap to said blood access device, said retaining cap
having a cap base ~or engaging said blood access device external rim forcing
said retaining cap and said blood access device together upon engaging said
retaining element and cap retaining ring.
According to a further aspect of the invention there is provided
an atraumatic valvlng mechanism for operation within a blood passageway of a
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blood access device having an external rim, said blood passageway adapted to
connect a blood vessel within a body to the body exterior, said valving
mechanism comprising:
a retaining cap and a retaining cap ring for engaging therewith
securing said retaining cap to said blood access device, said retaining cap
having an aperture and a restraining shoulder for slidably engaging said
blood access device external rim and said retaining cap having a cap base for
engaging said blood access device external rim, thereby forcing, in opposed
directions on either side of said external rim, said retaining cap and said
blood access device together upon engaging said retaining cap and retaining
cap ring.
Figure 1 is a side view in partial cross-section, illustrating
the present invention,
Figure 2 is a cross-sectional view taken about 2-2 of Figure l;
Figures 3J 4, 5 and 8 are pictorial views illustrating a portion
of the present invention; and
Figures 6 and 7 are side views, in partial cross-section, illustrating
the present invention.
Referring now to Figure 1, the blood access device within which the
atraumatic valving mechanism of this invention operates, will be discussed. The
blood access device, generally referred to as 1~ includes a blood passageway
3 having an external rim or lip 7, an anchor flange 15 and a flange means 5.
The flange means 5 is secured to a blood vessel 13 by means of suitable
surgical suture fiber 11.
Figure 1 further illustrates the use of vascular grafting material
19 which both provides for the minimizing of blood loss during implantation
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surgery and provides structural support for tissue ingrowt~l which allows the
blood vessel 13 and body tissues to be securely anchored to the blood access
device 1. In a preferred embodiment the vascular grafting material is made
of a Dacron, or a like fabric, and is impregnated with collagen. Figure 7
illustrates a patient's skin 18, fat 20, fascia 22 and muscle 24 within which
the blood access device 1 is anchored. A plugging means 31 is shown
positionedwithintheblood passageway 3 of the blood access device 1 and is
adapted to prevent blood flow therethrough and to expel blood from the blood
passageway 3 upon insertion. The blood passageway is preferably tapered as
illustrated in Figure 1, the taper having an untapered portion along its
tapered length as shown as a vertical ring 38 in ~igure 1 in order to provide
an improved seal between the plugging means 31 and the blood passageway 3.
The plugging means 31 is preferably restrainedwithinthe blood passageway 3
by means of a cap means 33 having a slo~ 34 at the top thereof and a threaded
retaining ring 35. As shown in Figures 7 and 8, the retaining ring 35 is
provided with an aperture 36 and a restraining shoulder 38 for sliding onto
blood access device 1 and engaging external rim or lip 7 for a secure seal.
As retaining ring 35 is threaded onto cap means 33, the base 40 of cap means 33
engages the upper portion 42 of external ring 7 and its restraining shoulder 38
engages the lower portion 44 of the external rim in an opposing direction.
Having briefly described the blood access device with which the
subject matter of this invention is utilized, the valving mechanism of this
invention will now be more fully discussed~
When it is desired to remove blood from a patient's vascular system,
restraining ring 35 is mthreaded, thereby allowing cap means 33 to be removed.
A connector or valve chamber generally referred to as 51 may be positioned
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about the external rim or lip 7 of the blood access device 1 and retained in
such a position by retaining element 83. The valve chamber Sl is preferably
provided with an engaging lip 53 which mates with ring 7 o~ the blood access
device 1.
In accordance with this invention~ plugging means 31 is provided with
an internally threaded aperture 55 adapted to engage the threaded portion 57
of a reciprocable stem member 59. The valve chamber 51 is further provided with
a cavity portion 65 adapted to receive at least a portion o~ the plugging
means 31 when said stem member 59 and connected plugging means 31 are pulled
from said blood passageway 3 so as to allow blood flow from the blood vessel
13 through the blood passageway 3.
: The retaining element 83 is provided with an aperture 84 which
allows the retaining element to slide into place about the valve chamber 51.
The retaining element 83 further includes external threads 85 and a
restraining shoulder 87 adapted to engage external rim 7 of blood access
device 1. Restraining element ring 89 is adapted to engage the shoulder 52
: of valve chamber 51 with retaining ring member 93. Internal threads 91 of
retaining ring 89 allow for the vice-like securing of the valve chamber 51
to blood access device 1. As the retaining element ring 89 is threaded onto
retaining element 83, as illustrated in Figure 1, retaining ring member 93
bears down on valve chamber shoulder 52 and restraining shoulder 87 exerts
an opposing upward force on the external rim on lip 7 of the blood access
device 1.
Reciprocable stem member 59 includes an annular slot 60 which
corresponds to the top of the valve chamber 51 when the reciprocable stem 59
is withdrawn in order to open the blood access device valves as shown in
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Figure 6. ~hen the reciprocable stem member 59 is in such position, the
slotted aperture 62 of tool 63 can be positioned abo~lt annular slot 60 in
order to lock the reciprocable stem member in the open position. The
opposed end 64 of the tool 63 is adapted to engage slot 34 of cap means
33 in order to assist in securing or removing the cap means 33.
