Note: Descriptions are shown in the official language in which they were submitted.
WO 94/20160 ~ ~ PCT/DK94/00098
1
Title: An infusion set for an intermittent or continuous administration of
a therapeutical substance.
Technical Field
The invention relates to an infusion set for an intermittent or continuous
administration of a therapeutical substance, such as insulin, said infusion
set comprising a cannula housing with a soft plastic cannula to be
placed inside the body of a patient, where the cannula together with the
~cannula housing form a through passageway the inlet of which into the
cannula housing is covered by a membrane, arid where said infusion set
comprises a needle hub with a needle to be inserted in the through
passageway of the cannula housing through the membrane, and further-
more guide means for centering the needle relative to the membrane and
the through passageway, as well as locking means for releasably inter-
locking the cannula housing and the needle hub.
Background Art
EP-PS No. 256,694 discloses an infusion set of the 'above type. This
infusion set comprises a cannula housing, in which the membrane is
placed relatively far down in the through passageway in the cannula
housing, a passageway between the membrane and the end facing away
from the cannula forming a guide for the needles to be inserted through
said membrane. The entire infusion set is shaped in a substantially
rotationally symmetrical manner about the longitudinal central axis of the
through passageway.
WO 88/03816 discloses an infusion set with a membrane secured at the
inlet to the through passageway through the cannula housing. The mem-
brane is retained between a beaded or melted down portion of the
material of the cannula housing and a bushing arranged immediately
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inside the membrane and forming a conical inlet to the
continued portion of the through passageway to the cannula.
This infusion set is also shaped in a substantially
rotationally symmetrical manner about the longitudinal
central axis of the through passageway.
Brief Description of the Invention
The object of the invention is to provide an
infusion set being relatively easy to handle and easy to
secure to the skin of the patient in question.
According to one aspect of the present invention,
there is provided an infusion set for an intermittent or
continuous administration of a therapeutical substance, said
infusion set comprising a cannula housing with a flexible
plastic cannula to be placed inside the body of a patient,
where the cannula together with the cannula housing form a
through passageway the inlet of which into the cannula
housing is covered by a membrane, and where said infusion
set comprises a needle hub with a needle to be inserted in
the through passageway of the cannula housing through the
membrane, and furthermore guide means for centering the
needle relative to the membrane and the through passageway,
as well as locking means for releasably interlocking the
cannula housing and the needle hub, wherein, in the
assembled state, the cannula housing and the needle hub
present a substantially planar rear side and a relatively
large width in a direction parallel thereto and
substantially perpendicular to the longitudinal central axis
of the through passageway such that the infusion set is
adapted for arrangement with the substantially planar side
abutting the skin of the patient; the guide means are co-
operating guide pins and guide openings on each side of the
needle and the through passageway; and the locking means are
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resilient locking pins arranged on their respective side of
the needle on the needle hub and comprising barbs, said
locking pins with barbs being adapted to be received in
their respective recess in the cannula housing, where said
recesses comprise shoulders mating said barbs.
According to another aspect of the present
invention, there is provided an infusion set for an
intermittent or continuous administration of a therapeutical
substance, said infusion set comprising a cannula housing
with a flexible plastic cannula to be placed inside the body
of a patient, where the cannula together with the cannula
housing form a through passageway the inlet of which into
the cannula housing being covered by a membrane and where
said infusion set comprises a needle hub with a needle to be
inserted in the through passageway of the cannula housing
through the membrane, and furthermore guide means for
centering the needle relative to the membrane and the
through passageway, as well as locking means for releasably
interlocking the cannula housing and the needle hub,
wherein, in the assembled state, the cannula housing and the
needle hub present a substantially planar rear side and a
relatively large width in a direction parallel thereto and
substantially perpendicular to the longitudinal central axis
of the through passageway such that the infusion set is
adapted for arrangement with said planar side abutting the
skin of the patient, and wherein the locking means are
resilient locking pins arranged on their respective side of
the needle on the needle hub and comprising barbs, said
locking pins with barbs being adapted to be received in
their respective recess in the cannula housing, where said
recesses comprise shoulders mating said barbs.
The infusion set of the above type is according to
the invention characterised in that in the assembled state
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the cannula housing and the needle hub present a
substantially planar rear side and a relatively large width
in a direction parallel thereto and substantially
perpendicular to the longitudinal central axis of the
through passageway, that the guide means are co-operating
guide pins and guide openings on each side of the needle and
the through passageway, and that the locking means are
resilient locking pins arranged on their respective side of
the needle on the needle hub and comprising barbs, said
locking pins with barbs being adapted to be received in
their respective recess in the cannula housing, where said
recesses comprise shoulders mating said barbs.
This infusion set is relatively easy to secure in
a reliable manner to the skin of the patient, said set being
arranged with the planar side abutting said skin. In
addition, it is relatively easy to handle because the guide
means ensure an easy alignment and centering of the needle
of the needle hub relative to the membrane of the cannula
housing before said membrane is penetrated. Finally, the
resilient locking pins ensure a relatively easy snap-
engagement and interlocking of the cannula housing and the
needle hub, and this engagement is easily releasable again
due to the resilience of the locking pins. An easy access
to the membrane of the reliably retained cannula housing is
possible by a removal of the
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needle hub so as to allow an insertion of the needle on a syringe, if any,
to be used shortly for administration of a therapeutical substance. A
coupling through a hose of the needle hub to a pump, such as an insulin
pump, renders it possible to easily connect said pump with the cannula
housing through the needle hub.
According to the invention, the cannula housing and the needle hub may
in the assembled state be, of a substantially circular shape with a sub-
stantially uniform thickness, the cannula housing being formed integral
with a projecting platform substantially covering the entire rear side of
the needle hub in the assembled state. In this manner a particularly
simple embodiment of the infusion set is obtained, and the cannula
housing is relatively easy to secure to the body of the patient by means
of plaster or the like tape provided with glue. Inter alia the projecting
platform provides a suitable surface for such a plaster because said
plaster is placed across said platform and is well protected below the
needle hub when said needle hub is correctly positioned and engages the
cannula housing. A second plaster may be placed across the cannula
housing presenting a good surface for said plaster due to its relatively
flat shape. Alternatively, an adhesive layer can be placed on the rear
side of the cannula housing with the projecting platform.
Furthermore according to the invention, the cannula housing and the
needle hub may in the assembled state be divided along a substantially
diametrically extending plane, which extends perpendicular to the central
axis of the needle and the through passageway, whereby the inlet to the
through passageway and to the guide openings provided in the cannula
housing is shaped in a projection extending perpendicular from the dia-
metrical plane and into a corresponding recess in the needle hub. In this
manner a well-suited embodiment is obtained, which is easy to handle
in particular in view of the dimensions usually being relatively small, i.e.
the external diameter being approximately 21 mm and the height being
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approximately 5 mm.The presence of the projection with the inlet to the
through passageway and to the guide openings in the cannula housing
as well as the corresponding recess in the needle hub allow a relatively
large length of said members, such as needle, guide openings and guide
pins co-operating therewith with the effect that the necessary guiding of
the needle in question is ensured. Furthermore it is ensured that the
needle completely penetrates the membrane when used.
Moreover according to the invention, the guide pins and the associated
guide openings and the locking pins and the associated recesses may be
symmetrically shaped relative to a central plane perpendicular to the
plane rear side and coinciding with the longitudinal central axis of the
needle and the through passageway, respectively. As a result, a particu-
larly simple embodiment of the invention is obtained.
Furthermore according to the invention the locking pins and the guide
pins may be placed on the needle hub, and the barbs of the locking pins
may face away from one another, as well as symmetrically shaped
recesses may be provided between the locking pins and the guide pins
so as to increase the resilience of said locking pins. In this manner a
particularly easy release of the engagement of the locking pins with the
associated shoulders on the cannula housing is obtained.
According to the invention the recesses receiving the locking pins may
everywhere be of a larger sectional area than the locking pins and at the
bottom immediately adjacent the shoulders co-operating with the barbs
on said locking pins the recesses may be connected with the top side of
the portion of the infusion set in question through an opening. In this
manner a particularly easy rinsing of dust particles is ensured during ,
bathing, as well as the risk of said dust particles depositing has been
minimized.
WO 94/20160 ' PCT/DK94/00098
According to the invention it is particularly preferred that the longitudinal
central axis of the through passageway inclines relative to the plane rear
side, the inlet end with the membrane being positioned farthest away
from said plane rear side relative to the location where the cannula exits
5 the cannula housing, and the guide means, the locking means, and the
needle on the needle hub may incline correspondingly at the same time.
As a result, a relatively easy insertion of a needle in the flat cannula
housing abutting the skin of the patient is ensured.
According to the invention the needle hub with the needle may be
shaped in form of an inserter needle hub to be used when the cannula of
the cannula housing is to be placed in the body of the patient, the
needle of the inserter needle hub extending all through the through
passageway and projecting outside the free end of the cannula, and at
the same time the inserter needle hub may comprise an extension pro-
jecting away from the locking means and facilitating the handling of the
infusion set during the placing. In this manner it is easy to place the
cannula housing with the soft cannula on the patient by means of an
inserter needle hub having a good an reliable grip in said cannula hous-
ing. After the placing, the inserter needle hub is relatively easily
removed.
Brief Description of the Drawina
The invention is explained in greater detail below with reference to the
accompanying drawing, in which
Fig. 1 is a front view of an infusion set according to the invention,
connected to a hose with a luer coupling to be connected with a pump,
Fig. 2 is a side view of the infusion set of Fig. 1,
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Fig. 3 illustrates on a larger scale the infusion set of Fig. 1,
Fig. 4 is a bottom view taken along the line III-Iii of the infusion set of -
Fig. 3,
Fig. 5 is a sectional view on a larger scale through the cannula housing
of the infusion set in a portion about a through passageway in which the
cannula of the cannula housing is mounted,
Fig. 6 illustrates the cannula housing seen from the end opposite the
cannula, '
Fig. 7 is a side view of the cannula housing of Fig. 6, where the cannula
has been removed,
Fig. 8 is a sectional view taken along the line VIII-VIII of Fig. 7,
Fig. 9 is a sectional view taken along the line IX-IX if Fig. 8 and showing
the through passageway for receiving the cannula not shown as well as
a membrane not shown either,
Fig. 10 is a sectional view taken along the line X-X of Fig. 8,
Fig. 11 is a sectional view taken along the line XI-XI of Fig. 8,
Fig. 12 is a side view of a connecting needle hub to be coupled to the
cannula housing,
Fig. 13 corresponds to Fig. 12, but whereby parts have been cut out for
the sake of clarity,
Fig. 14 is a top view of a preferred embodiment of an inserter hub to be
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coupled to the cannula housing so as to place said cannula housing on
a patient, whereby parts have been cut out for the sake of clarity, and
~ without an insertion needle,
Fig. 15 is a top view of the inserter hub of Fig. 14 together with an
insertion needle engaging a cannula housing, and
Fig. 16 is a side view of the inserter hub of Fig. 15.
Best Mode for Carrvingi Out the Invention
The infusion set of Figs. 1 and 2 comprises a cannula housing 1 with a
soft cannula 2 secured therein and manufactured in a conventional
manner of a suitable plastic material. The infusion set comprises further-
more a connecting hub 3 connected in a conventional manner through a
hose 4 with a luer coupling member 5 to, be used at the coupling thereof
to an insulin pump not shown.
Figs. 3 and 4 show the cannula housing 1 and the connecting hub 3 on
a larger scale. It appears clearly that together they are of a relatively flat
shape and of a uniform thickness and a substantially plane rear side 6.
When seen from the top, they are together of a substantially circular
shape, said shape only being interrupted by some recesses 7 and 8,
respectively, for facilitating a finger-handling. As illustrated in Fig. 3,
the
cannula housing 1 and the connecting hub 3 are substantially divided
along a diametrical central plane, a central projection 9 being provided
on said cannula housing 1 and projecting into a mating recess in the
connecting hub 3. In Fig. 3, the cannula 2 is slightly curved in order to
illustrate that it is bendable.
The cannula housing 1 and the connecting hub 3 are described in greater
detail below with reference to the following Figures.
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As illustrated in Fig. 5, the cannula 2 is arranged in a rectilinear bore 10
through the cannula housing 1. This bore 10 decreases stepwise when
seen from below and upwards relative to Fig. 5. The cannula 2 is
clamped in an extension in the through bore by means of an axially
projecting portion of a bushing 11. At the end opposite the can~ula 2,
the bushing 11 abuts a membrane 12 retained against the bushing 11 by
means of a beaded or melt down portion of the cannula housing which
is made of a suitable plastic material, such as polypropylene. The can-
nula 2, the bushing 11, and the membrane 12 in the cannula housing 1
are mounted in a conventional manner as described in the above WO
88/03816. The bushing 10 and the cannula 2 define a through passage-
way 13 with a longitudinal central axis designated the reference numeral
14 in the following Figures, Figs. 6 to 10 illustrating the cannula housing .
1 without a cannula 2 and membrane 11.
As illustrated in Figs. 6 to 10, the cannula housing comprises two guide
openings 15 and 16 and two locking openings 17 and 18 in addition to
the rectilinear through bore 10. These openings are symmetrically
shaped about a plane including the central axis 14 of the through pas-
sageway 13 and extending perpendicular to the rear side 6. The guide .
openings 15 and 16 are elongated openings of a substantially square
cross section; cf. Figs. 6, 8, and 10, which are adapted.to receive mat-
ing guide pins 21 and 22 on the connecting hub 3, cf. Fig. 13: As illu-
strated in Fig. 8, the guide openings 15 and 16 are arranged inside the
central projection 9 on the cannula housing 1 'in such a manner that the
orifices thereof in the illustrated embodiment are positioned on substan-
tially the same plane as the inlet to the through passageway 13 with the
central axis 14. The inlet of the through passageway 13 is indicated by
the reference numeral 23.
The locking openings 17 and 18 are of a relatively rectangular cross
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section gradually decreasing to a minimum value from the inlet on each
side of the projection 9, the locking openings 17 and 18 adjacent the
guide openings 15 and 16 and the central through bore 10 following a
rectilinear course parallel to the central axis 14 and consequently also
parallel to the guide openings 15 and 16. Immediately inside the mini-
mum sectional area of the locking openings 17 and 18, said sectional
area increases abruptly with the result that a shoulder 25 and 26, re-
spectively, is formed. Immediately inside this shoulder, the sectional area
decreases continuously while forming a curved bottom surface. The side
surfaces of the locking openings 17 and 18 extending perpendicular to
the symmetric plane through the central axis 14 are everywhere spaced
the same distance from one another, whereby, however, the locking
openings 17 and 18 at the bottom immediately inside the shoulders 25
and 26, cf. especially Fig. 11, are connected to the surface of the can-
nula housing through a shaft or channel 27 and 28, respectively, extend-
ing perpendicular from said locking openings 17 and 18.
The locking openings 17 and 18 are adapted to receive mating symmet-
rically shaped locking pins 31 and 32 on the connecting hub 3. As illu-
strated in Fig. 13, these locking pins 31 and 32 comprise their respec-
tive barb-forming extension 33 and 34 for a locking engagement behind
the shoulders 25 and 26, respectively, in the locking openings 17 and
18.
As illustrated in particular in Figs. 6 to 11, the cannula housing 1 com-
prises a thin platform extending outwards in front of the portion in
which the through bore 10 and the guide openings 15 and 16 and the
locking openings 17 and 18 are shaped. This platform is designated the
reference numeral 35 and is relatively thin and provided with a bottom
side continuing into the bottom side of the remaining portion of the
cannula housing 1 and thereby forming part of the rear side 6 of the
infusion set. When seen from the top, the cannula housing 1 with the
WO 94/20160 PCTIDK94/00098
platform 35 is of a circular shape.
As illustrated in Figs. 7, 8, 10 and 11, both the through bore 10, the
guide openings 15 and 16, and the locking openings 17 and 18 incline
relative to the rear side 6, all the inlets thereof being placed farthest '
5 away from said rear side 6. This inclination is in the illustrated embodi-
ment of the magnitude approximately 7°. Immediately outside the lock-
ing openings 17 and 18, the platform 6 is of a corresponding inclination,
whereas it is shaped with a substantially plane top side extending paral-
lel to the rear side 6 outside the projection 9. As illustrated in Figs. 12
10 and 13, the guide pins 21, 22 and the lockirig pins 31 and 32 on the
connecting hub 3 are of a corresponding inclination relative to the actual
body of the connecting hub 3. The body of the connecting hub com-
prises a plane bottom side 36, which in the mounted state extends
substantially parallel to the top side of the platform 35 on the cannula
housing 1. As a result, the cannula housing 1 can be secured by means
of a plaster placed across the platform 35.
As illustrated especially in Fig. 3, the locking pins 31 and 32 on the
connecting hub 3 are shaped with a relatively small sectional area rela-
tive to the sectional area of the locking openings 17 and 18, whereby a
relatively broad open channel is provided along the locking pins 31 and
32 when said locking pins engage the locking openings 17 and 18 in the
cannula housing 1. This channel communicates freely with the shafts 27
and 28 in the cannula housing 1. Fig. 3 illustrates for the sake of clarity
that the locking pins 31 and 32 with barbs 33 and 34 engage the shoul-
dens 25 and 26 in the locking openings. The embodiment shown in Figs.
fi to 10 of the cannula housing 1 does not render it possible to see the
shoulders 25 and 26 through the shafts 27 and 28.
As illustrated in Figs. 4 and 13, curve-shaped recesses 37 and 38 are
shaped on each side of the locking pins 21 and 22. These recesses
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ensure that the locking pins 31 and 32 can be easily moved by means of
finger forces into engagement with the shoulders 25 and 26 in the
locking openings 17 and 18 and out of said engagement again by means
of the finger forces of the patient.
Fig. 13 shows furthermore, that centrally the connecting hub 3 com-
prises a needle 40. When inserted through the membrane 12 in the
cannula housing 1, this needle provides a connection between the hose
4 of the infusion set and the through passageway 13 of the cannula
housing 1. As illustrated in Fig. 13, the length of the guiding pins 21
and 22 is longer than the freely projecting portion of the needle 40 with
the result that during the coupling to the cannula housing 1 the connect
ing hub 3 is placed with the needle 40 in a centred position relative to
the membrane 12 before said needle 40 is inserted through said mem
brane. In this manner it is ensured that the needle 40 is not damaged
during the coupling procedure.
An inserter needle hub is used for the insertion of the cannula 2 on the
cannula housing 1 into the patient. Such an inserter needle hub appears
from Figs. 14, 15 and 16 at the reference numeral 41: This inserter
needle hub is structured with completely the same shape as the con-
necting hub 3 with guide pins 42 and 43 and locking pins 44 and 45
with barbs 46 and 47. The portion of the inserter needle hub 41
adjacent the guide pins 42 and 43 and the locking pins 44 and 45 is
also identical with the connecting hub 3 with the result that the inserter
needle hub 41 completely fits in the cannula housing 1 and the locking
pins 44 and 45 possess the necessary flexibility. The inserter needle hub
41 is only distinguished from the connecting hub 3 by comprising an
extension 48 opposite the guide pins 42, 43 and the locking pins 44 and
45, said extension being of a suitable shape ensuring an easy retaining
by means of the fingers and allowing an easy handling of the inserter
needle hub 41.
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Centrally, the inserter needle hub 41 comprises a through opening re-
ceiving an insertion needle.This insertion needle is not shown in Fig. 14
for the sake of clarity, but as shown in Figs. 15 and 16 showing the
inserter needle hub 41 coupled to the cannula housing 1 with the can-
nula 2, the insertion needle is of such a length, cf. the reference numeral
51, that the point projects outside the cannula 2. As a result, the can-
nula 2 can be inserted through the skin of a patient in a conventional
manner. When the cannula 2 is correctly positioned in the patient, it is
left there together with the associated cannula housing 1, whereas the
inserter needle hub is removed. Subsequently, the cannula housing 1 is
used together with the connecting hub 3 being coupled thereto when it
is desired to administer a suitable therapeutical substance, such as
insulin from a pump.
The cannula housing 1 can also be used for administration of medicines
by means of a syringe, the needle of which is inserted through the mem-
brane, the inclination of the through passageway 13 in the cannula
housing 1 allowing an easy performance thereof. The connecting hub 3
is easily moved into engagement with the cannula housing 1 by the
guide pins 21 and 22 and the locking pins 31 and 32 being inserted in
the associated guide openings 15 and 16 and locking openings 17 and
18. During this procedure, the barbs 33 and 34 of the locking pins 31
and 32 slide against the outer oblique surfaces in the locking openings
17 and 18 and are pressed against one another until they grip behind the
shoulders 25 and 26 by a snap-effect. During this coupling movement,
the needle 40 passes automatically through the membrane 12, cf. Fig.
5, with a correct central positioning, whereby the point of the needle
does not hit the sides of the bushing 11.
When the connecting hub 3 is to be removed from the cannula housing
1, the user presses the locking pins 31 and 32 relatively easily together
in such a manner that the barbs 33 and 34 can pass the shoulders 25
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and 26 in the locking openings 17 and 18.
The cannula housing 1 is left secured to the skin of the patient by
means of suitably shaped plasters extending across the platform 35 and
across the body of the cannula housing 1. Such a plaster material is
suitably shaped with openings or recesses for uncovering the shafts 27
and 28 to the locking openings 17 and 18 in such a manner that dirt is
not collected therein and water can easily pass out during bathing.
According to a preferred embodiment of the invention, the cannula
housing 1 and the connecting hub 3 of the infusion set are in the
assembled state of an outer diameter of 21 mm and a height of 5 mm.
The volume behind the membrane in the through passageway 13 fills
approximately 0.003 ml, whereby the waste of the therapeutical sub
stance is reduced to a minimum during the administration. The cannula
housing 1 and the connecting hub 3 are made of a suitable plastic
material, such as polypropylene.
The cannula housing 1 with the platform 35 provides a large and
homogenous contact surface, whereby the pressure effect against the
skin is minimized. As a result, the user convenience is increased and the
risk of possible pressure wounds has been minimized.
The individual members can be assembled without the use of glue,
whereby the risk of possible allergic reactions caused thereby is mini-
mized. The position of the membrane 12 in immediate vicinity of the
inlet 23 to the through passageway 13 at the outer side of the projec-
tion 9 reduces the risk of dirt and other foreign bodies from penetrating
therein.
The invention has been described with reference to a preferred embodi-
ment. Many modifications can be carried out without thereby deviating
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from the scope of the invention.
