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Medical Patent Abstract
A needle free medical connector includes a housing with a first
port and a second port. The connector also includes a piston element
defining a fluid passageway between the first and second ports.
The piston element is movable between flow and non-flow positions.
The piston element has a compressible section having a variable
inner width that forms a part of the flow path through the connector.
As the piston is compressed to the flow position, the compressible
section self-expands in width thereby maintaining or increasing
the volume of the fluid passageway through the connector. The compressible
section has a configuration permitting the continuous flow of fluid
through its entirety.
Medical Patent Claims
What is claimed is:
1. A medical fluid connector configured to allow fluid to flow
through the connector when a cannula is inserted into the connector,
the connector comprising: a housing including a first port sized
to receive the cannula, a second port, a first inner housing portion
adjacent the first port and having a first internal diameter, and
a second inner housing portion having a second internal diameter
greater than the first internal diameter; and a moveable element
providing a fluid passageway through the moveable element connecting
the cannula and the second port of the housing, the moveable element
disposed within the housing to contact the cannula as the cannula
is inserted into the housing, the moveable element being moveable
between a first position in which the cannula has not been inserted
into the housing and a second position in which the cannula has
been inserted into the housing, the moveable element having: a head
element moveable in an axial direction away from the first port
in response to insertion of the cannula into the housing; a compressible
section having a first wall element, a second wall element, and
a variable internal volume between the first and second wall elements,
the compressible section configured to self-expand from a compressed
configuration to an expanded configuration, the first and second
wall elements being spaced farther apart when the compressible section
is in the expanded configuration, the compressible section being
moveable to a location adjacent the second inner housing portion
when the moveable element is in the first position, the compressible
section being moveable to a location away from the second inner
housing portion when the moveable element is in the second position,
the compressible section comprising a plurality of flexible membrane
elements that connect the first wall elements to the second wall
elements, the first wall elements and the second wall elements being
relatively inflexible; wherein when the moveable element is in the
first position, the second inner housing portion wall applies a
radially compressive force to the compressible section sufficient
to move the first wall element toward the second wall element; and
wherein when the moveable element is in the second position, the
compressible section self-expands during which the first wall element
moves away from the second wall element.
2. The connector cf claim 1 wherein the fluid passageway has a
passageway length that extends axially and that decreases when the
moveable element is moved from the first position to the second
position.
3. The connector of claim 2 wherein the fluid passageway defines
a fluid path volume, and when the moveable element moves to the
second position, the first and second wall elements of the compressible
section are configured to move apart by a selected width so that
the fluid path volume stays the same, thereby creating a neutral-bolus
effect.
4. The connector of claim 2 wherein the fluid passageway defines
a fluid path volume, and when the moveable element moves to the
second position, the first and second wall elements of the compressible
section are configured to move apart by a selected width so that
the fluid path volume increases, thereby creating a positive-bolus
effect.
5. The connector of claim 1 wherein the inner conduit of the compressible
section has a length that extends axially and that remains substantially
constant under the radially compressive force.
6. The connector of claim 1 wherein the head includes a normally
open bore and a moveable shoulder aijacent the bore; wherein when
the moveable element is in the first position, the shoulder contacts
the first inner housing portion and the bore is closed to fluid
flow; and wherein when the moveable element is in the second position,
the bore self-opens to allow fluid flow.
7. The connector of claim 1 wherein the moveable element further
comprises a spring section disposed between the compressible section
and the second port of the housing, the spring section configured
to axially contract, the spring section forming a part of the fluid
passageway; wherein when the moveable element is in the first position,
the spring section has a first spring section internal volume; and
wherein when the moveable element is in the second position, the
spring section has a second spring section internal volume greater
than the first spring section internal volume.
8. The connector of claim 7 wherein the fluid passageway defines
a fluid path volume, and when the moveable element moves to the
second position, the increase in the spring section internal volume
adds to the fluid path volume.
9. The connector of claim 1 wherein the first and second wall elements
are connected to each other by a fiexible element, the first and
second wall elements being stiffer than the flexible element.
10. The connector of claim 9 wherein the flexible element folds
into a space between the first and second wall elements.
11. A medical fluid connector configured to allow fluid to flow
through the connector when a cannula is inserted into the connector,
the connector comprising: a housing including a first port sized
to receive the cannula, a second port, a first inner housing portion
adjacent the first port and having a first internal diameter, and
a second inner housing portion having a second internal diameter
greater than the first internal diameter; and a moveable element
providing a fluid passageway through the moveable element connecting
the cannula and the second port of the housing, the moveable element
disposed within the housing to contact the cannula as the cannula
is inserted into the housing, the moveable element being moveable
between a first position in which the cannula has not been inserted
into the housing and a second position in which the cannula has
been inserted into the housing, the moveable element having: a compressible
section having a first wall element, a second wall element, and
a variable internal volume between the first and second wall elements,
the compressible section configured to self-expand from a compressed
configuration to an expanded configuration, the first and second
wall elements being spaced farther apart when the compressible section
is in the expanded configuration, the compressible section being
moveable to a location adjacent the second inner housing portion
when the moveable element is in the first position, the compressible
section being moveable to a location away from the second inner
housing portion when the moveable element is in the second position,
the compressible section comprising a plurality of flexible membrane
elements that connect the first wall elements to the second wall
elements, the first wall elements and the second wall elements being
relatively inflexible; and a spring section disposed between the
compressible section and the second port of the housing, the spring
section configured to axially contract, the spring scetion forming
a part of the fluid passageway; wherein when the moveable element
is in the first position, the spring section has a first spring
section internal volume and the second inner housing portion wall
applies a radially compressive force to the compressible section
sufficient to move the first wall element toward the second wall
element; and wherein when the moveable element is in the second
position, the spring section has a second spring section internal
volume greater than the first spring section internal volume and
the compressible section self-expands during which the first wall
element moves away from the second wall element.
12. The connector of claim 11 wherein the fluid passageway has
a passageway length that extends axially and that decreases when
the moveable element is moved from the first position to the second
position.
13. The connector of claim 12 wherein the fluid passageway defines
a fluid path volume, and when the moveable element moves to the
second position, the first and second wall elements of the compressible
section are configured to move apart by a selected width so that
the fluid path volume stays the same, thereby creating a neutral-bolus
effect.
14. The connector of claim 12 wherein the fluid passageway defines
a fluid path volume, and when the moveable element moves to the
second position, the first and second wall elements of the compressible
section are configured to move apart by a selected width so that
the fluid path volume increases, thereby creating a positive-bolus
effect.
15. The connector of claim 11 wherein the inner conduit of the
compressible section has a length that extends axially and that
remains substantially constant under the radially compressive force.
16. The connector of claim 11 wherein the moveable element further
comprises a head moveable in an axial direction away from the first
port in response to insertion of the cannula into the housing, the
head having a normally open bore and a moveable shoulder adjacent
the bore; wherein when the moveable element is in the first position,
the shoulder contacts the first inner housing portion and the bore
is closed to fluid flow; and wherein when the moveable element is
in the second position, the bore self-opens to allow fluid flow.
17. The connector of claim 11 wherein the fluid passageway defines
a fluid path volume, and when the moveable element moves to the
second position, the increase in the spring section internal volume
adds to the fluid path volume.
18. The connector of claim 11 wherein the flexible element folds
into a space between the first and second wall elements.
Medical Patent Description
INCORPORATION BY REFERENCE
We hereby incorporate by reference U.S. Pat. No. 5,676,346 to Leinsing.
BACKGROUND
The invention relates generally to medical connectors of the type
used in the handling and administration of parenteral fluids, and
more particularly, to a needle free connector employing a valve
mechanism that compensates for negative fluid displacement, i.e.,
drawing fluid into the connector, as the connector returns to its
unaccessed state from an accessed state.
Within this specification the terms, "negative-bolus effect,"
"positive-bolus effect," and "no-bolus effect"
are used to describe the operating characteristics of medical connectors
as the connector returns to its unaccessed state from an accessed
state. "Negative-bolus" effect describes the condition
during which fluid is drawn into the connector as the connector
returns to its unaccessed state from an accessed state. "Positive-bolus
effect" describes the condition during which fluid is expelled
out of the connector as the connector returns to its unaccessed
state from an accessed state. "No-bolus effect" describes
the condition during which fluid displacement is neutralized and
fluid is neither drawn into nor expelled out of the connector as
the connector returns to its unaccessed state from an accessed state.
Needle free medical connectors for injecting fluid into or removing
fluid from an intravenous ("IV") fluid administration
set are well known and widely used. One conventional type of such
a connector includes a housing having connection ports at both ends.
One connection port may comprise a female Luer port sized to receive
a blunt male cannula, such as a male Luer taper. The other connection
port may be located opposite the first port but in some cases is
located at a ninety degree or other angle to the first port, and
comprises a male Luer fitting. In many cases the second port of
the connector is permanently connected to IV tubing which in turn
is connected to an IV catheter that communicates with a patient's
venous system.
A valve is located within the connector and in most cases uses
the housing of the connector as part of the valve mechanism. When
the connector is accessed, the valve opens an internal fluid passageway
between the first and second ports. In some connectors, the internal
fluid passageway is defined by the internal boundaries of the connector
housing; in other connectors it is defined by an internal cannula
or hollow spike; and still in others, the internal fluid passageway
is defined by a compressible tubular body that carries the valve
mechanism.
Many needle free medical connectors create fluid displacement as
the connector is accessed and unaccessed. As the connector is accessed
by a blunt male Luer cannula tip inserted into the inlet or first
port of the connector housing, the valve mechanism is engaged. In
some connectors, the blunt cannula tip penetrates a valve device
to establish fluid communication with the internal fluid flow path
of the connector. In other connectors, the blunt cannula tip displaces
a valve device without penetrating it in order to establish fluid
communication with the fluid flow path. In either case, the volumetric
capacity of the fluid flow path is often reduced by the insertion
of the blunt cannula when accessing the connector. Subsequently,
when the blunt cannula is removed from the connector, the volumetric
capacity of the fluid flow path increases. This increase in the
volumetric capacity may create a partial vacuum or pressure reduction
in the fluid flow path that may draw fluid into the connector from
the second or downstream end of the connector. As previously mentioned,
the effect of drawing fluid into the connector in this manner is
referred to as a "negative-bolus" effect in that a quantity,
or "bolus," of fluid is drawn into the partial vacuum
or reduced pressure location within the connector.
A negative-bolus effect as the connector returns to its unaccessed
state is undesirable to some medical care providers and either a
neutral bolus or positive bolus effect is preferred. It is therefore
desirable to arrange for a valve mechanism that either does not
affect the capacity of the internal fluid passageway through the
connector as the connector is returned to its unaccessed state,
or that actually decreases it.
In one approach, the negative-bolus effect may be reduced or eliminated
by clamping the IV tubing between the connector and the IV catheter
prior to removal of the blunt cannula from the connector. This prevents
the back flow of fluid through the IV catheter and into the connector.
However this is an undesirable approach in that another device,
i.e. a clamp, is necessary and the care provider must remember to
engage the clamp with the tubing. Furthermore, the use of additional
devices adds expense and causes inconvenience in that they may not
be available at the time needed. Additional steps are also undesirable
in that most care providers are very busy already and would therefore
naturally prefer to reduce the number of steps in providing effective
care to patients rather than increase the number.
In another approach, one that disadvantageously also increases
the number of steps in the administration of medical fluids, the
operator continually injects fluid into the connector from the male
device while the male device is being disengaged from the connector.
By continuously adding fluid the operator attempts to fill the increasing
fluid volume of the fluid flow path through the connector as the
male Luer is being withdrawn, thereby reducing the likelihood of
a partial vacuum and thus the likelihood of a negative bolus forming
in the fluid flow path. However, this approach is also undesirable
in that not only does it add a step but may require some skill in
successfully carrying out the procedure.
The negative-bolus effect may also be reduced by the design of
the medical connector. As previously mentioned, some medical connectors
include an internal cannula or hollow spike housed inside the connector
body. The internal cannula or spike is positioned to force open
a septum upon depression of the septum onto the internal cannula
or spike by a blunt cannula. The internal cannula or spike has an
orifice at the top and, upon depression of the septum over the internal
cannula or spike, the internal cannula or spike is put directly
into fluid communication with the blunt cannula. The internal cannula
or spike provides a generally fixed-volume fluid-flow path through
the connector. Thus, as the septum returns to its closed position
the partial vacuum formed within the connector, if any, is not as
large as the partial vacuum formed in a connector having a more
volumetrically variable internal fluid passageway. A disadvantage
of typical connectors having an internal cannula or spike is a lower
fluid-flow rate caused by the small lumen in the cannula or spike.
Additionally, it has been noted that with the connector design having
a fixedly-mounted internal spike and a movable septum that is pierced
by that spike to permit fluid flow, such pierced septum may be damaged
with multiple uses and a leaking connector may result.
Another connector provides a valve mechanism that includes a flexible
body within which is located a relatively rigid leaf spring. The
housing of the connector includes an internal cannula and upon depression
of the flexible body by the introduction of a blunt cannula through
a port, the internal cannula forces the leaves of the leaf spring
apart. The leaves in turn force the top of the flexible body apart
and open a slit contained therein. The opening of the slit establishes
fluid communication between the accessing blunt cannula and the
lumen of the internal cannula. The expanding leaf spring also creates
a reservoir-type area between the flexible body and the outer wall
of the internal cannula in which fluid is held. As the external
blunt cannula is removed from the connector, the leaf spring and
reservoir collapse and fluid is forced out of the reservoir and
into the internal cannula lumen.
This positive displacement of fluid may result in a positive bolus
effect as the valve returns to its unaccessed state. However, the
valve mechanism is relatively complex with a leaf spring being incorporated
into a flexible member which adds some manufacturing concerns as
well as at least one additional part; i.e., the leaf spring. Manufacturing
concerns and additional parts can tend to cause expenses to rise,
an undesirable effect in the health care industry today where manufacturers
strive to provide effective products at lower costs. Further, the
reservoir-type system does not permit continuous flow through the
entire expandable flexible body section. Instead, fluid flows into
the reservoir and is retained there until the valve is returned
to its unaccessed state.
Hence, those concerned with the development of medical connectors
have recognized the need for a medical connector having a valve
mechanism that avoids the negative-bolus effect by producing either
a positive-bolus effect or a no-bolus effect. The need for a medical
connector that provides these effects without sacrificing fluid-flow
rate or structural simplicity has also been recognized. Further
needs have also been recognized such as the need for a medical connector
that is less expensive to manufacture, that is efficient in operation,
and that includes fewer parts. The present invention addresses such
needs and others.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the invention is directed to a medical
connector having a valve mechanism that provides either a positive-bolus
effect or a no-bolus effect, upon deactuation of the valve mechanism.
A connector is provided for controlling the flow of fluid, the connector
having an internal fluid passageway by which fluid may flow through
the connector, the connector comprises a housing having a first
port and a second port, the first port being adapted to receive
a blunt cannula and the second port adapted for fluid communication
with a fluid conduit, and a movable element positioned within the
housing, the movable element having a first position at which the
movable element blocks fluid flow through the housing and a second
position at which the movable element permits fluid flow through
the housing, the movable element comprising a head defining a bore
forming a part of the fluid passageway through the connector, the
head being configured such that when the movable element is in the
second position, the bore self-opens to permit fluid flow, the head
being further configured such that when the moveable element is
in the first position the bore moves to a closed configuration preventing
fluid flow, and a compressible section defining an inner conduit
forming a part of the fluid passageway through the connector, the
inner conduit having a width moveable between a first width and
a second width, the compressible section being configured so that
when the moveable element is in the second position the compressible
section self-expands so that the inner conduit has the second width,
the inner conduit being further configured so that when the moveable
element is in the first position the inner conduit moves to the
first width, wherein the first width is smaller than the second
width.
In more detailed aspects, the first and second widths of the inner
conduit of the compressible section are selected such that the fluid
passageway has a first volume when the movable element is in the
first position and a second volume when the movable element is in
the second position, the second volume being larger than the first
volume. Further, the first and second widths of the inner conduit
of the compressible section are selected such that the fluid passageway
has a first volume when the movable element is in the first position
and a second volume when the movable element is in the second position,
the second volume being approximately the same as the first volume.
Also, the inner conduit of the compressible section is configured
such that fluid may continuously flow through the entire inner conduit
when the movable element is located in the second position.
In other more detailed aspects, the connector further comprises
a support tube having opposing ends, the support tube defining a
lumen extending between the opposing ends, one end being in fluid
communication with the second port and the lumen forming a part
of the internal fluid passageway through the connector. The support
tube comprises a wall, the wall defining a slot providing a fluid
path between the exterior of the tube and the lumen. The support
tube is configured in relation to the moveable element such that,
when the movable element is in the second position, the lumen and
slot of the support tube are positioned, at least in part, within
the inner conduit of the compressible section such that fluid may
flow through the inner conduit of the compressible section, through
the slot, through the lumen of the support tube, and through the
second port of the housing.
In yet other more detailed aspects, the inner conduit of the compressible
section has opposing first and second ends, the first end being
adjacent the bore of the head, and the movable element defines an
orifice located at the second end of the inner conduit, the orifice
forming part of a flow path extending from the bore, through the
inner conduit, and out of the inner conduit through the orifice.
Further, the lumen and slot of the support tube extend, at least
in part, to a location outside the inner conduit of the compressible
section when the movable element is at the second position, and
said flow path further extends from the orifice, through the slot,
and into the lumen at the location outside of the inner conduit.
In further more detailed aspects, the moveable element further
comprises a spring section connected to the compressible section,
and said flow path further extends from the orifice, and into the
spring section whereby the spring section provides a portion of
the internal fluid passageway. The spring section is extended when
the moveable element is in the first position and when extended,
the spring section has a first internal volume, and the spring section
is compressed when the moveable element is in the second position
and when compressed, the spring section has a second internal volume,
the second internal volume of the spring section being greater than
the first internal volume of the spring section whereby the internal
volume of the portion of the flow path provided by the spring section
is greater when the spring section is compressed.
In other features, the housing includes a narrowed region adjacent
the first port, the head of the movable element being located in
the narrowed region when the movable element is in the first position,
the narrowed region being dimensioned so as to cause the bore of
the head to close. Additionally, the housing includes a constricted
region, the compressible section being located in the constricted
region when the movable element is in the first position, the constricted
region being dimensioned so as to cause the width of inner conduit
of the compressible section to move to the first width.
Yet further, the compressible section is connected to the head,
and the moveable element further comprises a spring section connected
to the compressible section, the spring section being adapted to
urge the movable element to the first position at which the compressible
section is placed within the constricted region. In a more detailed
aspect, the head, and the compressible section, and the spring section
are molded as an integral moveable element.
In additional features, the compressible section comprises a plurality
of relatively flexible membrane elements and a plurality of relatively
stiff wall elements, the membrane elements connecting together adjacent
edges of the wall elements. Further, the membrane elements are adapted
to fold radially inwardly when the inner conduit has the first width.
These and other aspects and advantages of the invention will become
apparent from the following detailed description and the accompanying
drawings, which illustrate by way of example the features of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of an assembled medical connector that incorporates
aspects of the present invention, showing a first port surrounded
by thread elements for receiving a blunt connector and a threaded
cuff, and a second port comprising a blunt male connector;
FIG. 2 is an exploded perspective view of the medical connector
of FIG. 1 showing the three components of the medical connector
of this embodiment, including an upper housing portion, a piston
element, and a lower housing portion;
FIGS. 3 and 4 are elevational views, at right angles to each other,
of the piston element shown in FIG. 2;
FIG. 5 is an end view of the self-opening head of the piston element
of FIG. 3 showing its normally-open marquise-shaped bore and having
the same orientation as the piston element of FIG. 3;
FIG. 6 is a perspective view in partial cross section of the piston
element of FIG. 2 with the section taken across the line marked
6-6, showing the self-expanding inner conduit in its normally expanded
condition;
FIG. 7 is a sectional elevation of the medical connector of FIG.
1, showing the connector in a non-accessed state with the piston
element in its first position in which the self-opening bore of
the piston head is closed to fluid flow by the narrowed first port
of the housing and the compressible section has been compressed
to its first width by a narrowed region of the housing;
FIG. 8 is an enlarged perspective view of the first port of the
connector of FIG. 1 showing the self-opening head of the piston
element in the first position with the marquise shaped bore closed
to fluid flow;
FIG. 9 is a sectional view of the medical connector of FIG. 7,
taken across the line marked 9-9 showing the compressible section
in its compressed configuration;
FIG. 10 is a sectional elevation of the medical connector of FIG.
1, showing the connector in an accessed state with the piston element
having been moved to its second position in which the self-opening
bore of the piston head has opened to fluid flow and the self-expanding
conduit of the compressible section has expanded to its normal "as-molded"
state, or second width, for increased internal volume;
FIG. 11 is a sectional view of the medical connector of FIG. 7
taken across line 11-11 showing the self-expanding conduit of the
compressible section at its normal "as-molded" state,
or second width for increased internal volume;
FIG. 12 is a detail view of the portion of FIG. 10 showing in enlarged
detail the interaction of the slot and lumen in the support tube
with the self-expanded inner conduit of the compressible section,
and the action of the spring section on the compressible section;
FIG. 13 is a cross-sectional view of the enlarged details of FIG.
12 showing the self-expanding inner conduit at its second width,
the support tube, the slot in the support tube, and showing in particular
orifices existing at the base of the inner conduit that permit fluid
flow from all parts of the conduit into the slot of the support
tube so that there is continuous fluid flow through the entire inner
conduit;
FIGS. 14 and 15 are schematic depictions of an operational principle
utilized by a medical connector that incorporates aspects of the
present invention; and
FIGS. 16 through 18 are perspective views of the piston element
showing alternative configurations of the spring section.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now in detail to the drawings in which like numerals
refer to like or corresponding elements among the several figures,
there is illustrated in FIG. 1 a side external view of a medical
connector that includes various aspects of the present invention.
The particular connector configuration exemplified in the figures
is for illustration purposes only. The connector may be embodied
in different configurations including, but not limited to, Y-connectors,
J-loops, T-connectors, tri-connectors, PRN adapters, slip Luers,
tubing engagement devices, access pins, vial adapters, blood tube
adapters, bag access pins, vented adapters, and others. The drawings
are for illustration purposes only.
FIG. 1 presents an embodiment of a medical connector 20 having
a housing 22 that is formed of an upper housing portion 24 and a
lower housing portion 26. The upper housing portion 24 has a first
port 28, that in this case is a female Luer connector port with
thread elements 30 located about the exterior. The lower housing
portion 26 terminates in a second port 32 that, in this case, comprises
a male Luer connector 34 defining a lumen 35 (lumen not visible
in FIG. 1) and with a threaded locking collar 36 (threads not visible
in FIG. 1). Together, the upper housing 24 and the lower housing
26 form the connector housing 22. The housing 22 may be molded of
a material containing a phosphorescent colorant to render the connector
20 visible in a darkened room or may be formed of a transparent
and/or opaque material.
Turning now to FIG. 2, an exploded, somewhat perspective view of
the connector 20 of FIG. 1 is shown. The connector 20 comprises
three parts in this embodiment: the housing 22 (see FIG. 1 for numeral
22) that comprises the upper housing portion 24 and the lower housing
portion 26. The connector 20 also includes a movable element or
piston element 38. As will be described in more detail below, the
piston element 38 is mounted over a support tube 40 that is formed
as part of the lower housing portion 26. In one embodiment, the
support tube 40 extends proximally from the center of the lower
housing portion 26 and has an inner lumen 42 extending the length
of the tube, and in the wall 44 of the tube, a longitudinal slot
46 is formed that may extend the length of the tube. In the embodiment
shown, the lower housing portion 26 also includes a vent 53 used
for the escape or intake of air from or to the housing during movement
of the piston element 38. In another embodiment, there may not be
a vent.
The housing of the embodiment shown in FIGS. 1 and 2 includes details
that aid in manufacturing and that lower the costs of manufacture.
As an example, the exterior surface of the upper portion 48 of the
lower housing portion 26 is molded to include a crown shaped outer
shell that has several crown points 50. Although not shown in FIG.
2, the interior of the lower portion 52 of the upper housing portion
24 is molded to include a complementary shaped pattern to the crown-shaped
lower housing portion. The crown shapes 50 of the lower housing
portion 26 mate closely with the complementary crown shapes (not
shown) of the upper housing portion 24 thereby facilitating a snap-fit
assembly of the medical connector housing. A snap ring 51 is also
included in the lower housing portion 26 and holds the upper housing
portion 24 in place on the lower housing portion 26 once the upper
housing portion has been forced over the snap ring 51. The geometry
of the crown shapes also prevents rotation of the upper housing
portion 24 with the lower housing portion 26 when they are snapped
together. Permanent assembly of the upper housing portion with the
lower housing portion may also be achieved by means such as ultrasonic
weld geometry, a spin weld, bonding, or by other means in other
embodiments. This design has been found to result in an efficiently
manufactured housing assembly that is accurately assembled, that
is quickly and efficiently snapped into a secure assembly.
Referring now to FIGS. 3 and 4 enlarged views of a resiliently
deformable piston element 38 are presented. The same piston element
38 is shown in both views, each rotated at right angles to each
other. The piston element includes three main sections; a piston
head 54, a compressible section 56, and a compressible section or
spring section 58. The compressible section is located between the
head and the spring. The piston element may suitably be molded as
one piece from a resilient material such as silicone or rubber.
The piston head 54 includes a top portion 60 that is elliptical
in outer shape, and a bottom, tapered shoulder section 62 that is
circular in plan cross-section. Referring now also to FIG. 5, a
marquise-shaped bore 64 is formed in the elliptically-shaped top
section 60. Located between the head 54 and the shoulder section
62 is an elliptical-conical section 61 that assists in causing the
marquise-shaped bore to tend to remain open. For further details
on the operation of the piston head, see U.S. Pat. No. 5,676,346
to Leinsing, which is incorporated herein by reference. Although
not shown in FIG. 3, 4, or 5, the compressible section 56 includes
a self-expanding inner conduit that forms one of the aspects of
the invention.
Referring now to FIG. 6, a perspective cross-sectional view of
the compressible section 56 is shown. As can be clearly seen, the
compressible section includes an inner conduit 66 formed by two
opposing relatively stiff wall elements 68 that are connected together
by two opposing relatively flexible membrane elements 70. The interconnection
of the wall elements 68 results in the inner conduit 66 with a width
72. It should be noted that the term "width" is not used
herein in a restrictive sense; that is, it is not used to indicate
the dimension in any particular direction within the inner conduit.
It is used instead in a general sense to indicate the interior cross-sectional
opening size of the inner conduit measured at right angles to the
longitudinal axis of the moveable element.
The membrane elements 70 are adapted to fold inwardly when a radially
compressive force is applied to the compressible section 56. Due
to the relative stiffness of the wall elements 68, the length of
the inner conduit 66 remains substantially constant under such radially
compressive force. When the radially compressive force is removed
or reduced, the inner conduit 66 is self-expanding and tends to
expand until it is open, as shown in FIG. 6, under the force provided
by the resilient material of the compressible section 56.
It can be noted that the inner conduit shown in FIG. 6 has an unusual
opening shape. However, the advantageous nature of this opening
shape will be apparent when later figures are discussed below.
Referring now to FIG. 7, the connector 20 of FIG. 1 is shown in
vertical cross-sectional format. It should be noted that the connector
depicted in FIG. 7 is in an unaccessed state. That is, no blunt
cannula has been inserted into its first port 28 for fluid communication
through the connector.
The upper housing portion 24 has sections of varying internal diameter.
The internal section directly adjacent the first port 28 includes
a standard ANSI Luer taper portion 100 that incorporates a very
slight inward taper. The center portion 102 has a larger internal
diameter than the Luer taper portion 100 and is separated from the
Luer taper portion 100 by a tapered lock portion 104. The bottom
portion 106 of the upper housing portion 24 has a larger internal
diameter than the center portion 102 and is separated from the center
portion by a tapered ramp portion 108. Thus, in relation to the
bottom portion 106, the center portion 102 represents a constricted
region, and, in relation to the center portion 102, the Luer taper
portion 100 represents a narrowed region. The bottom portion 106
has an inner diameter large enough to permit the inner conduit 66
to self-expand.
Referring now to both FIGS. 7 and 3, the spring section 58 is shown
and will be discussed in more detail. In the embodiment shown, the
spring section 58 is configured to include a plurality of relatively
stiff annular wall portions 110 (only two of which are indicated
by the numeral 110 to preserve clarity in the drawings), connected
to each other by relatively flexible annular hinges 112, together
forming the spring section. The annular wall portions 110 disposed
at the center of the spring section have an hourglass shape 113
(see FIG. 3) that permits their bending at the center point. The
hourglass shape and the hinges result in compression of the spring
58 in a controlled elastic fashion to assume a bellows-like shape
in response to an axially compressive force, as will be described
in relation to FIG. 10 below.
The inner diameter of the spring section 58 is selected to allow
positioning of the spring over the support tube 42 and the outer
diameter of the spring is selected to allow positioning of the spring
within the housing 22. The spring is easily slidable over the support
tube 42 in the embodiment shown but when a compressive force is
applied to the spring, the support tube prevents the spring from
buckling and assists the spring in a controlled change to a bellows-type
shape.
In the unaccessed state of the connector 20 as shown in FIG. 7,
the spring section 58 of the piston element 38 urges the compressible
section 56 through the ramp portion 108 of the upper housing portion
24 into the relatively constricted center portion 102. The location
of the compressible section 56 in this constricted location causes
compression of the compressible section and the inner conduit, as
shown in FIG. 9. A radially compressive force is applied to the
compressible section that causes the membrane elements 70 to fold
inwardly and the stiff wall elements 68 to move toward each other
as shown in FIG. 9, thereby substantially reducing the width 72
of the inner conduit 66 to a first compressed width, that is much
less than the second expanded width of the inner conduit 66 shown
in FIG. 6. Had there been any fluid in the inner conduit 66 when
it had its second width, as shown in FIG. 6, most, if not all, of
that fluid would be expelled as the inner conduit assumed the first
width shown in FIG. 9.
The cross-sectional view of FIG. 7 shows the interaction of the
three parts of the connector of the embodiment discussed. The upper
housing portion 24 includes the first port 28 that comprises a female
Luer connector port with thread elements 30 located about the exterior,
and is securely connected to the lower housing portion 26. The lower
housing portion 26 includes the second port 32 that comprises the
male Luer connector 34 with a threaded locking collar 36. The internal
threads are visible in FIG. 7. The lower housing portion 26 also
includes the support tube 40 integrally formed with the lower housing
portion. In this embodiment, the support tube has a length that
results in its location somewhat within the first housing portion
24 when the complete housing has been assembled. This feature is
also apparent from FIG. 2.
Further, the movable element or piston 38 is shown mounted over
the support tube and extending to the first port 28 of the upper
housing portion 24. The piston head 54 is within the narrowed Luer
taper region 100 of the first housing portion and this narrowing
has caused a compressive force to be exerted against the elliptical
portion 60 of the piston head 54, thereby causing the marquise-shaped
bore 64 to be closed. This closed configuration is more clearly
shown in FIG. 8 where the top of the piston head can be seen and
the closed bore 64 is clearly seen. It should also be noted that
this configuration permits easy wiping of the piston head before
use. This closed bore 64 blocks the fluid flow through the valve
in this unaccessed state.
It should be noted that the fluid volume within the connector 20
in this unaccessed state is defined by the open portion in the piston
head under the closed bore 64, the inner conduit 66 through the
compressible section, the lumen 42 of the support tube and the second
port 32. It is also informative to note that the support tube and
second port are rigid structures and their internal volumes do not
change with the connector being accessed, as will be discussed below.
While the bore 64 of the piston head may appear to be open in FIG.
7, it is closed. The particular orientation of the cross section
in FIG. 7 results in the marquise-shaped bore being shown along
its length, and thus has the appearance of being open. However,
a perspective view of the top of the piston head, such as that shown
in FIG. 8, demonstrates that the bore is closed.
In further reference to FIG. 7, the spring includes a base 114
that is mounted at the base 116 of the support tube 40. The spring
may be held in place at the base of the support tube by friction,
adhesive, or other means. For example, in the present embodiment,
the movable element 38 is placed in the lower housing portion 26
with the spring section 58 over the support tube 40 and the base
114 positioned as shown, and the upper housing portion 24 is placed
over the movable element 38 and secured to the lower housing portion
as described above. Because the dimensions of the upper housing
portion and the lower housing portion are such that there is constant,
although limited, axial compressive pressure placed on the movable
element 38, the spring section 58 tends to stay in position as shown.
This may be referred to as a pre-load force. Incorporated U.S. Pat.
No. 5,676,346 to Leinsing may be referred to for further details.
Extending proximally from the center of the base 116 is the support
tube 40. Extending distally from the base is the male-Luer taper
connector 34 having a lumen 35 that is coaxial with the lumen 42
of the support tube 40.
Turning now to FIG. 10, the connector 20 in an accessed state is
shown. A blunt cannula 130, which is a male Luer connector in this
case, has been inserted into the first port 28 into contact with
the top section 60 of the piston element head and has moved the
piston element so that the compressible section 56 is now partially
over the support tube 40. The spring 58 is now compressed.
As is described in U.S. Pat. No. 5,676,346 to Leinsing, the configuration
of the piston head results in the bore 64 of the piston head being
self-opening. That is, the bore 64 is normally open and radial compressive
forces must be applied to the piston head to close the bore. The
elliptical-conical portion 61 (see FIGS. 3 and 4) of the piston
element head 54 also uses the axial force from insertion of the
male Luer 130 to facilitate the opening of the bore 64. Thus, when
the male cannula 130 presses the piston head into the larger interior
of the housing 22 and radial compressive forces are removed from
the piston head, the bore 64 self-opens to now permit fluid flow
through the connector 20.
Similarly, the compressible section 56 is configured so that the
inner conduit 66 is self-expanding. That is, the inner conduit 66
is normally at its second width and radial compressive forces must
be applied to the compressible section to close the inner conduit,
or to force it to have its smaller first width. Thus, when the male
cannula 130 presses the piston head into the larger interior of
the housing 22, and radial compressive forces are removed from the
compressible section, the inner conduit 66 self-expands to its larger
second width that will now permit a larger fluid volume within the
fluid passageway of the connector 20. This larger width either exactly
compensates for the decrease in length of the fluid passageway through
the connector or adds additional volume to the fluid passageway.
As can be seen by reference to FIG. 10, pressing the male cannula
130 into the connector 20 shortens the length of the fluid passageway
through the connector from the length in FIG. 7 and would otherwise
thereby reduce the volume of the fluid flow path also. However,
the increased width of the inner conduit volumetrically counteracts
this decrease in length. This is discussed in more detail below
in regard to FIGS. 14 and 15.
In FIG. 10, it is shown that the compressible section 56 and the
inner conduit 66 are now located partially over the support tube
40. This arrangement can be seen in greater detail in the enlarged
diagram of FIG. 12. The support tube however includes a lumen 42
through which fluid may flow and a longitudinal slot 46 in the wall
44 of the tube through which fluid may continuously flow into and
out of the support tube lumen and into and out of the inner conduit
as shown in FIG. 10. Fluid that may reach the spring section will
also flow into or out of the slot of the support tube so that continuous
flow occurs throughout the connector when in the accessed state.
No reservoirs or dead space of any nature exist so that each part
of the fluid passageway is adapted for continuous flow through it.
Turning now also to FIG. 11 in conjunction with FIG. 10, the interaction
of the support tube 40, its lumen 42, and its slot 46 with the inner
conduit 66 may be seen from another angle. FIG. 11 is a cross sectional
view of FIG. 10, which is a connector in the accessed state. In
FIG. 11, a possible orientation of the slot of the support tube
with the inner conduit wall is shown. In this configuration, the
slot 46 of the support tube resides against one of the stiff walls
68 of the inner conduit. This particular positioning does not prevent
fluid flow through the inner conduit because orifices 132 are provided
at the bottom of the inner conduit to provide for fluid flow between
the inner conduit and the proximal portion of the spring section.
The enlarged diagram in FIG. 13 shows the orifices 132 more clearly.
In the accessed state, the point of connection between the spring
section 58 and the compressible section 56 may be configured to
define the orifices 132 through which the support tube 40 protrudes.
Thus, at the distal end of the inner conduit 66, a plurality of
gaps or orifices 132 may be defined between the piston element 38
and the support tube 40 which collectively provide a fluid flow
path between all portions of the inner conduit 66 and the proximal
section 133 (see FIG. 12) of the spring section 58, from whence
fluid may flow into the lumen 42 of the support tube via the slot
46.
Thus, the compressible section 56 is configured so that when the
connector 20 is accessed by a blunt cannula 130, fluid may flow
continuously through the entire inner conduit 66 without a reservoir
being developed at any point in which fluid may be trapped, held,
or retained. The piston element 38 is configured to provide a larger
fluid passageway width at the location of the compressible section
56 when the connector is in the accessed state, as shown in FIG.
10, thus increasing the volume of the fluid passageway or keeping
it the same as the volume of the fluid passageway in the unaccessed
state, as shown in FIG. 7.
It will be appreciated that, when the slot 46 of the support tube
is oriented so that it is facing one of the membrane elements 70
in FIG. 11, fluid may flow directly between the lumen 42 of the
tube and the inner conduit 66 via the slot 46 or in parallel with
fluid flow through the orifices 132.
To briefly reiterate, in the accessed state as shown in FIG. 10,
the internal fluid passageway through the connector 20 is through
the bore of the piston element, through the head of the piston element,
through the entire inner conduit 66, through the lumen 42 of the
support tube, and through the second port 32. It will be appreciated
that flow may be reversed when fluid is withdrawn through the connector.
It should be noted that in comparison to FIG. 7, the internal fluid
passageway of FIG. 10 has been shortened by the amount that the
blunt cannula 130 has entered the first port 28, or, put another
way, the amount by which the inner conduit 66 now covers the support
tube 40. However, the self-expansion of the inner conduit to a greater
width has volumetrically compensated for the decrease in length
of the internal fluid passageway. Conversely, as the blunt male
connector 130 is withdrawn from the first port 28, the internal
fluid passageway through the connector will lengthen, but at the
same time the width of the inner conduit will decrease. If the decrease
in width decreases the volume of fluid in the internal fluid passageway
of the connector by an amount greater than the increase in length
causes an increase in volume, a bolus of fluid may be expelled by
the connector 20 through the second port.
In further detail, the inner conduit will be discussed. Referring
to FIGS. 9 and 11, the membrane elements 70 may be adapted to fold
inwardly when a radially compressive force is applied to the compressible
section. Due to the relative stiffness of the wall elements 68,
the length 134 of the inner conduit 66 remains substantially constant
under such radially compressive force. Where the radially compressive
force is removed or reduced, the inner conduit 66 is self-expanding
and tends to expand under the force provided by the resilient material
of the compressible section 56.
In regard to the spring section 58, the piston element 38 resiliently
deforms so as to permit the annular portions 110 to alternatingly
deform inwardly and outwardly, while allowing rotation to occur
mainly at the hinges 112, as exemplified in FIG. 10. A comparison
of the two spring section 58 configurations shown in FIGS. 7 and
10 will reveal that when in the configuration of FIG. 10, the spring
section 58 also contributes to the increased internal fluid passageway
through the connector resulting from insertion of the male Luer
into the connector. Because the longitudinal slot 46 extends substantially
along the entire spring section length in the configuration of FIG.
10, fluid may continuously flow within the spaces 59 formed between
the spring section and the support tube 40 resulting from the action
of the hinges 112 during compression of the spring section.
Referring to FIG. 7, the spring section 58 is in an extended configuration
when the moveable element 38 is in the first position; i.e., the
connector 20 has not been accessed by a male Luer. As can be seen,
the spring section is located quite close to the support tube 40
along its entire length. At this location, the spring section has
a first internal volume. When the connector 20 has been accessed
and the moveable element 38 has been located at its second position
as shown in FIG. 10, the spring section 58 has been compressed.
In compression, parts of the spring section remain close to the
support tube 40 while other parts move outwards forming the spaces
59 indicated in FIG. 10. Taking the internal volume of the spring
section, which includes the parts near and the parts farther away
from the support tube 40, the spring section has a second internal
volume, and that second internal volume is greater than the first
internal volume (extended, or uncompressed, spring section). Because
of this configuration and the fact that the slot in the support
tube extends into the spring section, the spring section forms a
part of the internal fluid passageway through the connector. In
the embodiment shown, the spring section contributes to a net volume
increase of that internal fluid passageway when the connector is
accessed. Conversely, when the connector is unaccessed; i.e., when
the male Luer 130 is being withdrawn, the spring section will collapse
to the configuration shown in FIG. 7 thereby contributing to a decrease
in the net volume of the internal fluid passageway through the connector.
It will be appreciated that modifications in the shapes of the
spring section are possible. Changes may be made to affect flow
rate, restoring force, spring section return rate, volume, differential
volume between compression and extension configurations, sealing,
piston retention, and acceptance of blunt cannulas. Modifications
include changing the number of annular sections, wall thickness
and height, or may include different configurations of the spring
section entirely, as exemplified in FIGS. 16-18.
The use of the support tube 40 also has another advantage. Because
it takes up volume in the internal fluid passageway by virtue of
its size, there is less volume for fluid in that passageway when
the connector is not accessed (shown in FIG. 7). This results in
a smaller fluid passageway in the unaccessed state than might otherwise
exist if no support tube were present. Because it is rigid, it has
a fixed volume that will not change.
FIGS. 14 and 15 are schematic drawings that present the concept
of the adjustment of the volume of the internal fluid passageway
through a connector based on expansion and contraction of a part
of that passageway. In FIG. 14, a schematic connector 136 is shown
that includes an internal fluid passageway 138 having a length 140
linking a first port 142 with a second port 144. In FIG. 14, the
single dashed line adjacent the first sport 142 is used to indicate
the closed bore of the piston head. Forming part of the fluid passageway
138 is an inner conduit 146 having a first width 148. In FIG. 15,
a blunt cannula 150 has been inserted into the first port 142 of
the connector 136 and has shortened the internal fluid passageway
138 which now has a length shown by numeral 154. The difference
between the length 140 of the internal fluid passageway in FIG.
14 and the length 154 of the internal fluid passageway in FIG. 15
is shown by numeral 156. If nothing else were to change, the volume
of the internal fluid passageway 138 of FIG. 15 would now be less
than that of FIG. 14, and a negative bolus effect could be expected
upon removal of the male cannula 150. However, the width 160 of
the inner conduit 146 in FIG. 15 has been expanded to be greater
than the width 148 of the inner conduit of FIG. 14. It will be appreciated
that, by appropriate selection of the expanded and compressed widths
of the inner conduit, the volume of the fluid path 138 can be made
to increase, stay the same, or decrease when a blunt cannula is
made to access the connector 136. Where the volume increases, a
positive bolus-effect is created when the cannula is removed from
the connector. Where the volume remains the same, a neutral-bolus
effect is created, and, where the volume decreases, a negative-bolus
effect is created.
Turning now to the operation of the medical connector 20, the connector
is initially in its unaccessed state or closed position as shown
in FIG. 7. The resiliency of the spring section 58 of the piston
element 38 causes the piston head 54 to be biased into the narrowed
ANSI Luer taper portion 100. The shoulder 62 of the piston head
54 contacts the tapered lock portion 104 of the upper housing portion
24 and controls the position of the top of the piston head 54 in
relation to the edge of the first port 28 thus forming a swabable
surface therewith. The sharp pointed ends of the marquise-shaped
bore 64 facilitate a tight seal upon compression of the bore along
its minor axis and by compression of the top section 60 of the piston
head 54 along its major axis.
Just prior to accessing the connector with a male Luer connector
at the first port 28, the top surface of the piston head 54 and
the edge of the first port may be cleaned by, for example, passing
a sterilizing swab over the smooth surface of the piston head lying
flush, slightly below, or slightly above the upper surface of the
first port. The connector is then ready to be accessed by a standard
male Luer connector with or without a threaded locking collar.
The tip of a male Luer connector is brought into contact with the
proximal surface of the top section 60 of the piston head 54. The
application of sufficient pressure causes the spring section 58
of the piston element 38 to axially contract and to compress in
a bellows-like configuration so that orifices 132 are defined between
the spring section 58 and the support tube 40. As the spring section
58 axially contracts, the piston head 54 moves out of the narrowed
ANSI Luer taper portion 100 of the upper housing portion 24 and
into the center portion 102. As the piston head 54 clears the tapered
lock portion 104 and is moved into the center portion 102, the larger
internal diameter of the center portion allows the top section 60
of the piston head to self-expand and to tend to assume its normal
elliptical shape and the same action allows the bore 64 to tend
to self-open to assume its normally open marquise-shape bore configuration
thereby opening a fluid passageway through the connector and the
piston head 54.
Further, as the spring section 58 contracts under axial pressure
of the male Luer tip 130, the compressible section 56 moves in the
distal direction from the constricted center portion 102 of the
upper housing 24 into the larger diameter bottom portion 106 of
the upper housing, allowing the compressible section to self-expand
and to assume an expanded configuration. As the compressible section
56 moves in the distal direction, the support tube 40 will extend
into the inner conduit 66.
As the blunt cannula 130 becomes fully inserted in the connector
20, the compressible section fully self-expands, thereby expanding
the width of the inner conduit. Flow may now occur through the connector.
The internal fluid passageway through the connector has expanded
in width to volumetrically compensate for the decrease in length,
and fluid flows continuously through every part of the internal
fluid passageway of the connector. Additionally, fluid flows through
the entire compressible section 56 due to the slot 46 in the wall
44 of the support tube 40 and the orifices 132 that permit fluid
flow through the distal end of the inner conduit 66 into the proximal
section 133 of the spring section and into the slot 46.
When the blunt cannula 130 is withdrawn from the connector 20 to
allow the connector to return to the non-accessed state, the restoring
force generated by the spring section 58 of the piston element 38
causes the compressible section 56 to be urged proximally past the
ramp section 108 into the constricted confines of the center section
102 of the upper housing portion 24 and thus into the compressed
condition where the inner width 72 of the inner conduit decreases
to its first width, as shown in FIG. 7. Thus, the volume of the
fluid passageway through the conduit may decrease, depending on
the selected dimensions of the compressible section 56 and its inner
conduit 66. If so, a bolus of fluid that was within the inner conduit
will be expelled through the second port 32. Simultaneously, the
elliptical top portion 60 of the piston head 54 is guided by the
tapered lock section 104 into the ANSI Luer taper section 100 where
it is once again urged into a narrowed circular shape to close off
the orifice 64 and reestablish a positive seal against fluid flow
through the connector 20.
Thus there has been shown and described a new and useful valve
for use in medical connectors that provides a controllable bolus
effect. Depending on the expanded and compressed widths selected
for the inner conduit 66 of the compressible section in relation
to the configuration of the balance of the piston element 38, a
positive-bolus, neutral-bolus, or negative-bolus effect can be achieved
as the connector is placed in an unaccessed state from an accessed
state.
It will be apparent from the foregoing that while particular embodiments
of the invention have been illustrated and described, various modifications
can be made without departing from the spirit and scope of the invention.
Accordingly, it is not intended that the invention be limited, except
as by the appended claims.
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