Note: Descriptions are shown in the official language in which they were submitted.
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P-625
REUS~BLE INJECTION CATHETER
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1~ Field of the Invention. The present inven-
tion relates to a medication delivery system, and
more particularly, concerns a disposable reservoir
cassette for liquid medication which can be delivered
to a patient preferably through the use of a roller
type infusion pump~ and a reusable injection catheter
to contain the liquid medication as it passes from
the reservoir cassette to a patient.
2. Description of the Prior Art. Many diseases
of man and animal are treated by the subcutaneous,
intramuscular or intravenous injection of medication
into the body of the afflicted being. For example, a
common method of treating diabetes mellitus is
through the subcutaneous injection of insulin on a
daily regimen. This method of treatment fails to
entirely normalize glucose metabolism and therefore
effects other aspects of metabolism and body chemis-
try. It is now recognized that relatively large
doses of insulin spaced many hours apart can cause
microvascular, neuropathic and other complications
which may be minimized or eliminated by more frequent
smaller subcutaneous doses of insulin. However, more
frequent doses present convenience problems for the
patient who must continuously carry an ample supply
of needles and syringes, and must also remember the
exact times for insulin injection and find a private
place for administering the injection. In addition,
the pain and tissue trauma resulting from frequent
injections of small doses of insulin makes this
approach impractical. Xt is more desirable to
subcutaneously place an indwelling needle in the
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patient and intermittently deliver the insulin into
the patient's body, or to continuously deliver
insulin through an indwelling intramuscular needle or
intravenous catheter. However, continuous or
intermittent injection over a period of time, for
example, twenty-four hours, is impractical without a
lightweight compact delivery system which can be
attached to the patient's body or clothing while not
interfering with his or her daily activities.
soth Muller (U.S. Pat. No. 3,384,080) and
Maxwell (U.S. Pat. No. 3,198,385) teach devices
capable of continuous injection of fluids into the
human body. However, these devices are large and
cumbersome and are not readily adaptable to be
conveniently attached to the patient's body. Muller
requires a separate reservoir which adds to the bulk
of the pump unit. Also, a large separate reservoir
system presents a potentially life threatening
problem in the event that safety devices fail and the
pump injects the entire reservoir into the patient.
Maxwell teaches a very complex device for high
pressure injection in which an ampule is drawn
through a pair of rollers, one of which is powered,
to squeeze the fluid therefrom.
Xanthopoulos (U.S. Pat. No. 4,187,057) teaches a
disposable cassette for use in a peristaltic infusion
pump and Brown (U.S. Pat No. 4,256,437) also is
concerned with a peristaltic infusion pump. The
Xanthopoulos pump appears large and cumbersome
and not suitable for attachment to a patient's body.
It is also intended to pump intravenous fluids from a
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P-625
separate reservoir. Xanthopoulos teaches moving the
cassette in and out of the operative position, in
which pump rollers engage and compress the cassette's
first tubular section, by moving the entire cassette
in a plane which is parallel to the plane of rotation
of the rollers. This type of structure is unde-
sirable in that moving of the cassette in the plane
of the roller may cause medication to be injected
into the patient as a result of the relative motion
between the cassette tube and the rollers.
The patent application of Albisser et al.,
presently licensed to the assignee hereof, (Serial
No. 267,364 and filed on May 22, 1981) teaches a
compact device for controlled subcutaneous injection
lS of medicaments such as insulin in discrete quantities
at selected time intervals. Albisser et alO describe
a compact roller type pump designed to deliver
liquid through a flexible tube connected to a sub-
cutaneously positioned needle. The user of the
Albisser et al. invention places the tube needle
assembly into the roller pump and then inserts the
needle into the insulin vial. The pump is then
used to draw insulin from the vial into the tube.
The needle is then removed from the vial and placed
into the patient. This method requires removing the
needle from the patient every time the supply of
medication is exhausted.
Also of interest is U.S. Pat. No. 4,235,234
issued to Whitney et al. which teaches a subcutaneous
injection system including a locator pad carrying a
needle with a right angle bendD The part of the
* (now U.S. Patent 4,601,707 issued July 22, 1985)
... .
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P-625
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needle before the bend is in the plane Gf the locator
pad and the part after the bend, which inc]udes
the sharpened end, projects a prescribed distance,
generally perpendicular, from the locating pad.
~ince the locating pad lies against the patient's
s]cin, the depth of needle penetration is positively
controlled.
U.S. Pat. No. 2,847,995 to Adams shows a ~nown
spring resilient valve sheath used to seal the end of
a needle cannula. This structure is commonly used
with evacuated blood collection tubes having a rubber
stopper. Pushing the tube stopper toward the end of
the cannula will cause the cannula to pierce the
sheath and pass through the stopper, thus estab-
lishing fluid communication between the interior ofthe evacuated blood collection tube and the cannula.
As the cannula penetrates the rubber stopper, the
sheath is compressed in an accordion-like fashion.
When the needle is removed from the stopper, the
sheath returns to its original position sealing the
cannula.
With the above-mentioned deficiencies of the
prior art in mind, it is desired to provide a dis-
posable reservoir cassette which can be inserted into
and removed from a pump mechanism without removal of
the delivery needle from the injection site and to
allow the use of the same catheter tubing and de-
livery needle with consecutively used reservoirs. It
is further desired to provide a disposable reservoir
cassette which can be purchased by the user in a
pre-filled condition or filled by the user with a
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P-625
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simple inexpensive filling system. It is still
further desired to provide a disposable reservoir
cassette which is easy to install and easy to remove
from the pump and which will not force additional
medication into the patient during the installation
and removal procedures and which will also allow the
user to conveniently carry and use spare reservoir
cassettes.
SUMMARY OF THE INVENTION
The disposable reservoir cassette of the present
invention comprises a compressible reservoir, a
gas-permeable, liquid-impermeable element at one end
of the reservoir and access means at the other end of
the reservoir for gaining entry thereinto. A housing
means is provided for holding the reservoir so that
the access means is accessible for transferring fluid
from the reservoir and for allowing contact with
the reservoir by externally applied forces adapted to
compress the reservoir against the housing means and
drive an~ fluid contained therein in the direction
toward the access means.
In a preferred embodiment of this aspect of the
invention, a disposable reservoir cassette for use
with a roller pump mechanism in delivering liquid
medication to a patient comprises a flexible reser-
voir tube, an air permeable, liquid-impermeable
element at a first end of the tube and a purge
chamber connected to the second end of the tube. A
purge chamber includes a cylinder, a pierceable
4~
P-625
septum at one end of the cylinder and a sealing
member at the other end of the cylinder. The septum,
cylinder and sealing member define a cavity for
accepting and storing a portion of the fluid orig~
inally contained within the tube. The sealing member
contains a centrally located orifice which is in
fluid communication with the second end of the tube.
Air venting means between the interior of the purge
chamber and the exterior of the purge chamber is
provided to allow gases to escape the purge chamber
when fluid enters same. Also provided is a rigid
cassette housing containing the reservoir tube
therein. This housing includes an opening to accept
an externally positioned roller of the roller pump
lS mechanism and a rigid substantially circular backstop
supporting the tube along the length of the tube.
The housing has a transfer port therein and means to
fixedly hold the tube adjacent to the backstop so
that the second end of the tube is adjacent to the
transfer port. Securement means is provided for
cooperating with the roller pump to position and
removably hold the housing so that the backstop is
located substantially adjacent to the path of
the roller pump roller whereby rotation of the
roller compresses the tube sufficiently to drive any
fluid contained therein in the direction toward the
second end of the tubeO
In another aspect of the present invention, a
reusable injection catheter comprises a flexible
conduit, injection means associated with the first
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P-625
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end of the conduit for delivering medication into a
patient and a cannula extending outwardly from a
second end of the conduit with a free end o~ the
cannula being furthermost from the conduit. Sealing
means is associated with the cannula for normally
preventing the passage of fluid therethrough. This
sealing means is responsive to externally applied
force or fluid pressure for allowing fluid passage
through the cannula.
In a preferred embodiment of this other aspect
of the invention, a reusable injection catheter for
use with a source of externally supplied pressurized
fluid comprises a flexible tube, a first cannula
extending outwardly from a distal end of the tube
adapted for insertion into a patient and a connector
housing at a proximal end of the tube. This housing
has a forward end, a rearward end adjacent to the
tube and a passageway therethrough. The passageway
is in fluid communication with the tube. A second
cannula extends outwardly from the forward end of the
housing and is in fluid communication with the
housing passageway. A free end of the second cannula
is furthermost from the housing. Also provided is a
resilient sleeve covering the free end of the second
cannula to prevent fluid passage therethrough. This
sleeve includes a closed end adapted to be pierced by
the free end of the second cannula upon the applica-
tion of an external force to the sleeve in a direc-
tion along the second cannula toward the housing thus
allowing fluid passage through the second cannula.
The sleeve is further adapted to return to its
P-625
original position upon termination of the external
force. Attachment means associated with the housing
cooperates with the source of externally supplied
pressurized fluid to removably hold the housing in a
fixed position relative thereto. In this fashion the
second cannula and the sleeve are held in a position
with the closed end of the sleeve being pierced by
the second cannula whereby the second cannula is free
to accept fluid through its free end.
In accordance with the principles of the present
invention, a number of advantages and objectives are
achieved. Primarily, the present invention provides
a disposable reservoir cassette and a reusable
injection catheter for use in a compact medication
del7very system for injecting continuous or incre-
mental doses of liquid medication into a patient. The
present invention is particularly adapted for
utilization with a programmable body-attachable
roller pump. The present invention provides a
disposable reservoir cassette which can be purchased
by the user in a pre-filled condition or filled by
the user with a simple ine~pensive filling device.
This reservoir cassette is easy to install and easy
to remove from the roller pump and will allow the
user to conveniently carry and use spare reservoir
cassettes. In addition, the reservoir cassette can
be inserted and removed from the roller pump without
removal of the delivery needle from the injection
site and, as a result of the purge chamber, it allows
the use of the same catheter tubing and delivery
needle for consecutively used reservoirs. The
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P-625
reusable injection catheter assists in this respect
by providing a resilient sleeve or sealing means
which prevents medication from leaving the catheter
during a change of reservoirs. Further, containment
5of all of the medication within the cassette avoids
the problems associated with delivering medication
from a large adjacent reservoir.
BRIEF D~SCRIPTION OF T~lE DR~WINGS
Fig. 1 is a top plan view of the preferrecl
disposable reservoir cassette attached to a program-
10mable roller pump with the preferred reusable injec-
tion catheter attached to the reservoir cassette;
Fig. 2 is a perspective view of the preferred
disposable reservoir cassette and the preferred
reusable injection catheter;
15Fig. 3 is exploded perspective view of the
preferred disposable reservoir cassette;
Fig. 4 is an enlarged top plan view of the
reservoir tube, as part of the reservoir cassette
with purge chamber and the air-permeable, liquid-im-
20permeable element;
Fig. 5 is an enlarged top plan view of the lower
housing portion of the reservoir cassette;
Fig. 6 is an enlarged top plan view of the
reservoir tube with purge chamber and air-permeable,
25liquid-impermeable element in the lower housing
portion of the reservoir cassette;
Fig. 7 is an enlarged cross-sectional view of
the disposable reservoir cassette of Fig. 1 ta~en
along line 7-7;
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P-625
1 0 -
Fig. 8 is an enlarged partial cross-sectional
view of the preferred disposable reservoir cassette
and the roller pump of Claim 1 taken alon~ line
~-8;
5Fig. 9 is an enlarged side elevation view of the
air-permeable, liquid-impermeable element of the
preferred disposable reservoir cassette;
Fig. 10 is a cross-sectional view of the element
of Fig4 9 taken along line 10-10;
lOFig. 11 is an enlarged side elevation view of
the purge chamber of the preferred disposable reser-
voir cassette;
Fig. 12 is a cross-sectional view of the purge
chamber of Fig. 11 taken along line 12-12;
15Fig. 13 is a perspective view of the preferred
reusable injection catheter;
Fig. 14 is an enlarged partial cross-sectional
view, looking along the longitudinal axis, of the
reusable injection catheter of Fig. 13;
20Fig. 15 is an enlarged side elevation view of
the connector housing with resilient sleeve of the
preferred reusable injection catheter;
Fig. 16 is a cross-sectional view of the connec-
tor housing of Fig. 15 taken along line 16-16;
25Fig. 17 is the connector housing of Fig. 16
further showing the second cannula projecting through
the slit in the resilient sleeve;
Fig. 18 is an enlarged side elevation view of
the connector housing and cover member of an alterna-
30tive embodiment of the reusable injection catheter;
Fig. 19 is a cross-sectional view of the connec-
tor housing and cover member of Claim 18 taken along
line 19-19;
P-625
Fig. 20 is a perspective vie~ showing the
hold-down member open for assembly to the first
cannula end of the preferred injection catheter;
Fig. 21 is a perspective view showing first
cannula end of the preferred injection catheter with
first cannula inserted into the hold-down member;
Fig. 22 is the assembly of Fig. 21 with hold-
down member folded on an axis perpendicular to the
flexible conduit;
1 Fig. 23 is the assembly of Fig. 22 with the
hold-down member further folded in a position for
cannula insertion into the patient;
Fig. 24 is an enlarged side elevation view of
the distal end of the preferred injection catheter in
use;
Fig. 25 is a perspective view showing the
medication delivery system attached to one desirable
position on a patient's body;
Fig. 26 is an enlarged partial cross-sectional
view showing a syringe being used for filling the
preferred disposable reservoir cas~ette;
Fig. 27 is an enlarged top plan view of the
preferred disposable reservoir cassette partially cut
away to show interaction with the preferred reusable
injection catheter and the roller pump;
Fig. 2~ is an enlarged partial cross-sectional
view showing the preferred reusable injection cathe-
ter connected to and in fluid communication with the
preferred disposable reservoir cassette; and
Fig. 29 is an enlarged partial cross-sectional
view of the preferred disposable reservoir cassette
schematically showing medication entering the purge
chamber. (On sheet with Fig. 24~
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P-625
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DETAILED DESCRIPTION
While this invention is satisfied by embodiments
in many different forms, there is shown in the
drawings and will herein be described in detail
preferred embodiments of the invention with the
understanding that the present disclosure is to be
considered as exemplary of the principles of the
invention and is not intended to limit the invention
to the embodiments illustrated. The scope of the
invention will be measured by the appended claims and
their equivalents.
Turning to Fig. 1, an operable medication
delivery system 29 for the delivery of liquid medi-
cation, such as insulin, to a user includes a dis-
posable reservoir cassette 30, a programmable
electricall~ controlled roller pump 200 and a reus-
able injection catheter 100~ The roller pump is
preferably a reusable electro-mechanical miniature
roller pump adapted to be attached to the human body
and similar to the pump described in the above
mentioned application of Albisser et al. The prin-
ciple of operation of the delivery system is based
upon a peristaltic motion modified to deliver the
entire contents of disposable reservoir cassette 30
in the single pass of a roller. As will hereinafter
be described, the contents of the reservoir cassette
are delivered through the injection catheter and into
the patient.
The roller pump of the embodiment being de-
scribed includes a rigid dust proof water resistant
P-625
body housing 201 which contains a drive mechanism/ an
electronic package and a power source, all of which
are not shown. Projecting outwardly from housing 201
is roller driving arm 202 and a pump roller 204. The
drive mechanism which drives roller 204, through arm
202, is an internal spring (not shown) which is
rewound each time the pump is loaded with a new
reservoir cassette. The winding is performed when
the roller driving arm is manually rotated in a
counter-clockwise direction from an empty position
205 to a load position 206. An internal indexing
mechanism (not shown) constrains the clockwise roller
movement to discrete angular increments of 105
degrees and is activated by the electronic package.
The electronic package times and activates the
indexing mechanism and is adjustable to provide
automatic roller movement from one increment every
88.2 minutes to one increment every fifteen minutes.
The rate of roller incremental movement is propor-
tional to the basal rate which is the rate insulin is
delivered from the delivery system. Adjustments can
be made in the basal rate, for example, so that U-100
insulin is delivered from 0.34 units per hour to 2.00
units per hour. The basal rate is adjusted up or
down by activating buttons 207 or 209 on the housing
and observing the rate in a liquid crystal display
210~ A bolus button 211 is provided to permit manual
control of roller incrementation and to allow de-
livery of insulin in amounts greater than the basal
rate~ This feature allows the user to receive
additional insulin when needed, for example, before
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P-625
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meals. On/off switch 214 is provided to control that
part of the electronic package which supplies power
to the internal indexing mechanism, thereby acting as
a control to start and stop the incremental movement
of the pump roller.
Turning to Figs. 2-4 disposable reservoir
cassette 30 includes a flexible reservoir tube 34~ an
air-permeable, liquid-impermeable element 35 at a
first end 68 of the reservoir tube and a purge
chamber 36 at a second end 58 of the reservoir tube.
The reservoir tube is shapable a]ong its length so as
to take on a circular, ring-shaped configuration.
A rigid cassette housing 37 contains the reservoir
tube, the purge chamber and the element. The housing
includes a rigid substantially circular backstop ~1
which supports the reservoir tube along the length o~
the tube, an opening 42 to accept the roller pump
roller and a transfer port 72 adjacent to the purge
chamber. Cassette housing 37 includes an upper0 housing portion 39 and a lower hosing portion 40.
As seen in Figs. 5-7~ lower housing portion 40
includes a circular purge chamber recess 44, a
circular re~ervoir tube recess 45, a shoulder 46
between recess 44 and recess 45 and a purge chamber
shoulder 47 at the end o~ purge chamber recess
4~ opposite shoulder 46. Also included in lower
housing portion 40 is circular trans~er port recess
69, one of two connector housing retaining grooves
70, sleeve retaining wall 75 and circular cannula
conduit recess 74. When the reservoir tube with
purge chamber and element attached is placed in
P-625
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lower housing portion 40, as shown in Fig. 6, purge
chamber 36 is received in recess 44 between shoulders
46 and 47. Likewise, element 35 at the opposite end
of the reservoir tube is received in an element
recess 49 in the lower housing portionn Upper
housing portion 39 contains similar recesses,
grooves and shoulders so that when the upper housing
and lower housing are joined, the purge chamber and
element are enclosed therein. As a result of this
structure, the longitudinal motion of the reservoir
tube is limited to thereby reduce dosage inaccuracies
that may result from the reservoir tube moving along
the backstop in response to roller motion. A
similar result can be achieved by using adhesive to
attach the reservoir tube along the length of the
backstop or by providing cooperating structure along
the tube and along the backstop to maintain the
relative position of the tube with respect to the
backstop. It will be apparent to one skilled
in the art that numerous constructions could be used
to contain the reservoir tube within the housing
portions and that the arrangements described above
are exemplary of these many possibilities. The
joining of the upper and lower housing portions also
causes the formation of transfer port 72 and a
circular cannula conduit which includes cannula
conduit recess 74 and a similar recess in housing
portion 39. The cannula conduit connects the purge
chamber recess and the transfer port.
In the preferred embodiment of the present
invention, the housing portions are made of thermo-
plastic material which can be joined together via
P-625
-16-
cooperating structure in the housing portions,
fasteners, adhesive or the use of compatible welding
techniques. The preferred disposable reservoir
cassette is a compact structure measuring approxi-
mately 2.0 inches (5.08 cm) wide by 2.0 inches ~5.08
cm) high by 0.3 inch (0.76 cm) thick. It is also
within the purview of this invention to include
housing portions which are removably attached to each
other so that the housing portions are reusable while
the reservoir tube, with purge chamber and element
attached, is disposable after one use. Housing
portions may be made to removably attach to each
other by using threaded screw type fasteners,
snap fasteners or other suitable reusable connecting
means to hold the housing portions together.
Averting to Figs. 1 and 8, disposable reservoir
cassette 30 must be held in a removably fixed rela-
tionship to roller pump 200 and in particular to the
path of pump roller 204. Since medication is de-
livered to the patient through the action of the pump
roller as it moves along a circular path compressing
flexible reservoir tube 34, it is important that
the reservoir cassette be restrained from rotational
movement with respect to the roller pump. If the
cassette rotates in the direction of roller motion,
less medication will be delivered than is required
while rotational motion of the cassette in the
direction opposite of roller motion will cause
more medication to be delivered than is required.
Also, as will become apparent, it is important that
the reservoir cassette be installed and removed
9~
P-625
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without rotational movement with respect to the
roller pump so that medication is not delivered or
air drawn into the system during the removal and
installation procedure.
To prevent rotational motion of disposable
reservoir cassette 30 with respect to roller pump
200, positioning sur~aces 77 are provided on cassette
housing 37. These positioning surfaces are adjacent
to positioning blocks 215 which are attached to the
roller pump housing via positioning screws 216.
Positioning blocks 215 can be adjusted to be in
close proximity to cassette housing positioning
suraces 77 and then Eixed in that position by
tightening screws 216. It can be seen that rota-
tional motion of the disposable reservoir cassette
with respect to the roller pump can be substantially
restrained through this structure. It should
be noted that close control of the dimensional
tolerances of the various positioning surfaces should
allow positioning blocks to be made without adjusing
screws and as an integral part of the roller pump
housing. The above described cooperating surfaces
also restrict the motion of the disposable reservoir
cassette with respect to the roller pump so that the
disposable reservoir cassette must be moved in a
direction substantially perpendicular to the path ~f
the pump roller when it is being attached to and
removed from the roller pump, thus minimizinq
the chance of accidental medication delivery or
drawing air into the system.
Retention springs 217 apply pressure to
cassette housing outwardly extending exterior longi-
tudinal ribs 79 to hold the reservoir cassette
P-625
-18-
against the roller pump housing. rrhe retention
springs can be deflected out of the way by forced
movement of the reservoir cassette in a direction
perpendicular to pump roller motion, thus providing a
snap-fit arrangement to hold the reservoir cassette
in a removably fixed relationship with the roller
pump. Retention springs 217 are held in in place by
retention screws 216.
~igs. 9 and 10 depict a preferred air-permeable,
liquid-impermeable element 35 which includes a plug
51 with a passageway 52 therethrough. The plug
includes a flanged portion 54 which is larger in
diameter than the outside diameter of the reservoir
tube and a body portion 55 which is inserted in
the reservoir tube. The plug may be held in the
reservoir tube through the use of an interference fit
wherein the outside diameter of body portion 55 is
slightly larger than the inside diameter of the tube
or by the use of adhesives or the like. Air-perme-
ablel liquid-impermeable membrane 56 is attached to
the plug so that passageway 52 is covered. With
this construction, gases entering or leaving the plug
end of the reservoir tube must pass through the
membrane while the liquid medication contained within
the reservoir cannot pass therethrough. In some
cases, as will later be shown~ it may be desirable to
use a porous membrane with a maximum pore rating of
about 0.5 microns ~or filtering particulate matter
including microorganisms from gas entering into the
reservoir tube. The membrane may be attached to plug
51 via the use of adhesives or heat sealing. It is
~s~o
P-625
_1 9--
also within the purview of this invention to include
a plug made entirely of air~permeable, liquid-imper-
meable material thereby eliminating the need for a
passageway and a separate membrane.
Adverting to Figs. 11 and 12, there is il-
lustrated preferred purge chamber 36 which includes a
cylinder 57, a pierceable septum 59 located at one
end of the cylinder and a sealing member 60 located
at the other end of the cylinder. The cylinder and
the sealing member may be made of rigid materials or
resilient elastomeric materials, with the latter
being preferred. Pierceable septum 59 is preferably
made of resilient elastomeric material with a nor-
mally closed slit 63 centrally located therein. Slit
63 is forced open by components, hereinafter de-
scribed in more detail, when medication is being
placed into or forced out of the reservoir tube.
In addition to the slit, it is within the purview of
this invention to include other self-sealing struc-
tures such as a solid elastomeric septum, a duck-bill
or miter valve, or the like, as part of the pierce-
able septum, with the slit structure being exemplary
of the many possible variations. Adhesive may be
used to attach pierceable septum 59 to cylinder
57. The sealing member includes a centrally located
orifice 61 which is in fluid communication with
second end 58 of reservoir tube 34. Reduced diameter
portion 62 of the sealing member is inserted into the
second end of the reservoir tube. An interference
f it wherein the outside diameter of reduced diameter
portion 62 is larger than the inside diameter of the
~ ~s~
P-625
-20-
reservoir tube may be used to join these parts.
Adhesive or other suitable means may also be use~ to
join the purge chamber and the reservoir tube. A
purge chamber port 73 contains an air-permeable,
li~uid-impermeable filter 64 which communicates
between the interior of the purge chamber and the
exterior thereof so that gases which may be contained
in the purge chamber may exit when medication enters
the purge chamber. Filter 64 may be in the form of
an element attached within port 73 in cylinder 57 or
in the form of a sheet attached so that it covers
port 73 in cylinder 57.
Turning now to Figs. 13-17, preferred reusable
injection catheter 100 includes a flexible con~uit
101 having a lumen 102 therethrough and a first
cannula 104 at distal end 103 of the flexible conduit
in fluid communication with the conduit. The first
cannula has a sharpened beveled point 106 for easy
insertion into the patient. Adhesive is preferably
used to hold the first cannula in the flexible
conduit. It is preferred that the first cannula
include a bent section 117 in an area adjacent to the
distal end of the flexible conduit, The bent portion
should cause the free end of the f irst cannula to
2~ project outwardly from flexible conduit 101 at an
obtuse angle relative to the longitudinal aa~is of and
within the flexible conduit. It is preferred, but
not necessary, that this obtuse angle be within the
range of about 120 to 160 degrees. The length of the
flexible conduit depends on the distance bet~een the
roller pump and the injection site. It is preferred
- ~2S~
P-~25
that the inside diameter of flexible conduit 101 be
about 0.43 mm (0.017 inches).
A connector housing 107, having a passageway 109
therethrou~h is provided at proximal end 113 of
conduit 101. Preferably, the connector housing is
made of a thermoplastic material and is attached to
the flexible conduit via the use of adhesive or other
suitable means. Connector housing projections 108
extend radially outwardly from the surface of
connector housing 107 and are sized and positioned to
engage connector housing retaining grooves 70 of
cassette housing 37. A second cannula 105 extends
outwardly from the connector housing and is in fluid
communication with passageway 109. The second can-
nula may be an integral part of the connector
housing or a separate cannula attached to the
housing. As will be shown, it is not necessary for
the second cannula to have a sharpened point. A
resilient sleeve 110 covers a free end 111 of the
second cannula to prevent fluid passage there-
through~ This sleeve is made of elastomeric material
with a normally closed slit 112 at the closed end
thereof. As will be explained in more detail herein-
after, the application of an external Force F to
resilient sleeve 11~ in the direction of connector
housing 107 causes the sleeve to collapse in an
accordion-like fashion and allow second cannula to
pass through slit 112 thus ailowing fluid to flow
into the second cannula. Withdrawal of the external
force allows the resilient sleeve to return to its
original position in which it pre~ents fluid flow
~5~ P-625
-22-
through the second cannula and therefore prevents any
liquid medication which may be in the flexible
conduit from exiting through the second cannula.
It is also within the purview of the present
invention to include a one-way valve means in the
connector housing passageway to prevent fluid from
leaving the flexible conduit through the second
cannula while force or fluid pressure in a direction
into the second cannula toward the flexible conduit
opens the valve means and allows fluid flow
therethrough.
As best shown in Figs. 17 and 18, an alternative
embodiment of the reusable in~ection catheter in-
cludes a connector housing 119 and connector housing
projections 120 which are sized and positioned to
engage connector housing retaining grooves 70. A
second cannula 121 extends outwardly from the
connector housing. A shield member 122 removably
engages the connector housing through an interference
fit between shield member inside diameter 124 and a
shield member engaging surface 125 on the housing.
Shield member 122 is provided to protect second
cannula 121 from damage and contamination when
connector housing 119 is not engaging the disposable
reservoir cassette. Also provided is venting member
126 which allows air trapped within the shield member
to escape while the shield member is being engaged
with the connector housing. Without venting member
126 the engagement of the shield member and the
connector housing could force air into the flexible
conduit through second cannula 121. This is unde-
sirable since air in the flexible conduit can be
~5~9~
P-6~5
-23-
injected into the patient. It is desirable to
construct venting member 126 of a fi~ter material
which will prevent bacteria from passing therethrough
so that second cannula 121, if initially sterile,
will not be contaminated during subsequent handling
before the shield member is removed~ One skilled in
the art will recognize that there are numberous ways
to design a cover member to engage a housing, e.g.
screw fitting and snap-fit, and that there are
numerous ways to provide for venting in a cover
member and that the above described configuration is
exemplary of these many possible configurations.
Referring now to Figs. 20-24, a hold-down member
114 is provided for securing first cannula 104 to
patient P after it has been inserted into the sub-
cutaneous fat layer Q below patient's skin S. The
hold-down member may be a circular ~lexible pad with
a first side 115 coated with a contact adhesive.
After the first cannula is placed through a cen-
trally located hole 116, member 114 is folded over on
itself on an axis which is transverse to ~lexible
conduit 101. The contact adhesive causes member 114
to stay in this folded condition, as best shown in
Fig. 22. Me~ber 114 may now be ~olded again along an
axis su~stantially parallel to flexible conduit 101.
In this position, as shown in Fig. 23, the patient
may grasp the hold-down member and use it as a handle
to assist in the subcutaneous placement of the first
cannula. After the cannula is properly placed, the
patient releases his grip on member 114 and it
returns to the shape shown in Fig. 22 so that it can
~s~as~
P-625
-24-
be taped to the patient's body. The bend in first
cannula 10~ facilitates the subcutaneous placement of
the first cannula. As best shown in Fig. 24 the bend
also demands that the needle be lifted away from the
skin when being removed, a motion that is constrained
by the hold-down member while it is attached to the
patient. It is desirable to coat surface 118, which
faces the patient, with an adhesive that causes it to
removably adhere to the skin and to further cover
this adhesive with a backing paper (not shown). Once
the needle is properly placed, the patient may remove
the backing paper and press surface 118 against skin
S, causing the hold-down member to remain removably
attached to the slcin. It is also within the purview
of the present invention to include a hold-down
member without a hole for accepting the first cannula
wherein the distal end of the flexible conduit
is attached to the hold-down member rather than being
contained between its layers.
Referring to Fig. 25, programmable roller pump
200 may be secured to the patient's body via flexible
waist band 212~ Since there are a wide variety of
possible roller pump locations on the patient or
within adjacent garments, the waist mounting il-
lustrated is intended to be exemplary of these many
possible positions. Once a location for the program-
mable roller pump is chosen, the injection-site may
be any convenient portion on the patient's body which
is near to the pump and also contains enough fatty
tissue to assure the proper subcutaneous placement of
first cannula 10~ of the injection catheter, using
hold down member 114.
~5~ ) P-625
~verting to Fig. 26, to fill the preferred
disposable reservoir cassette ~if not prefilled), the
user first transfers liquid medication from a stan-
dard medication vial, containing a needle-penetrable
closure (not shown), to a hypodermic syringe 65 with
needle cannula 66 attached thereon. The needle
cannula is then pushed through pierceable septum 59
and into sealing member 60 of the purge chamber. The
medication is then expelled from the syringe into the
reservoir tubeO Gases in the reservoir tube which
are displaced by the medication exit through element
35, while liquid medication cannot pass there-
through. If an air bubble becomes trapped within the
medication in the reservoir tube, it may be elimi-
nated by withdrawing some of the medication back into
the syringe along with the air bubble and then
manipulating the syringe so that the medication can
be returned to the reservoir tube without the air
bubble. It can be seen that air drawn înto the
reservoir tube may contain bacteria. This may
not present a problem if the medication contains a
bacteristatic agent. However, bacteria can be
prevented from passing through the element if it is
constructed of material having a maximum pore rating
?5 f about 0.5 micron so that the element is capable of
filtering microorganisms from the gas entering the
reservoir tube. It should be noted that cannula 66
prevents medication from entering interior portion 67
of the purge chamber.
In use, as best shown in Figs. 27, 2~ and 29
together with Figs. 1 and 8, the patient, with the
P-625
-26-
programmable roller pump attached to his body,
rotates roller driving arm 202 in a counter-clockwise
direction to the load position and inserts a dis-
posable reservoir cassette, filled with liquid
medication, into the roller pump by placing the
reservoir cassette between positioning blocks 215 of
the roller pump housing and forcing it directly
toward the roller pump to cause retention springs
217 on the pump housing to engage the external ribs
on the reservoir cassette housing. Reusable injec-
tion catheter 100 is then connected to the reservoir
cassette by inserting connector housing 107 lnto
transfer port 72 in the cassette housing so that
connector housing projections 108 are aligned
with connector housing retaining grooves 70 in the
cassette housing. The connector housing retaining
grooves will only allow the connector housing to
enter the transfer port to a depth which places
second cannula 105 in fluid communication with
reservoir tube 34, which is filled with medication.
At this point, twisting the connector housing locks
it into the reservoir cassette in a bayonet fashion.
It should be noted that during insertion sleeve
shoulder 71 in cassette housing 37 forces resilient
sleeve 110 toward the connector housing allowing the
second cannula to pierce slit 112 in the resilient
sleeve and to thereby open the second cannula
for accepting medication from the cassette reservoir.
Also, during insertion, exposed free end 111 of
second cannula 105 pierces slit 63 in pierceable
septum 5g and enters oriice 61 of sealing member 60
such that the second cannula is now in fluid communi-
cation with flexible reservoir tu~e 34.
~5~
P-625
-27-
Pump roller 204 is now advanced to the start
position, as best seen in Fig~ 1, by depressing and
holding bolus button 211. Advancing the pump roller
to the start position causes the roller to compress
flexible reservoir tube 34 and force a portion of the
medication contained therein into the injection
catheter simultaneously filling it with medication
and forcing all air out of the the fluid path. Eirst
cannula 104 may now be inserted subcutaneously into
the patient and attached to the patient using hold-
down member 114, as previously described. At this
time, the roller pump timing mechanism is activated
by moving on/off switch 214 to the on position.
Now, the roller advances intermittently, injecting
controlled doses of medication into the patient, over
a medication delivery period which may be within the
range of about several hours to forty-eight hours
depending on factors such as the type of insulin
being used and the dosage required by the patient.
As the roller pump advances, the medication ahead
of the roller is expelled from flexible reservoir
tube 34 through second cannula 105, into flexible
conduit 101, through first cannula 104 into the
patient. It should be noted that second cannula 105
prevents medication from entering interior portion 67
of the purge chamber. The interior of the flexible
reservoir tube behind the roller, which no longer
contains medication, is filled with air entering
through air~permeable, liquid-impermeable element 35.
If the first end of the flexible reservoir tube were
sealed, rather than containing element 35, there
P-625
--28--
would be a tendency for the portion of the flexible
reservoir tube which no longer contains medication to
expand and create a negative pressure in the reser-
voir tube located behind the advancing roller thus
requiring more power to advance the roller. This
tendency is eliminated by the presence of element
35. At the end of the medication delivery period,
the roller pump timing mechanism is deactivated by
moving on/off switch 214 to the off position. Then
the injection catheter is disconnected from the
reservoir cassette, while first cannula 104 remains
subcutaneously attached to the patient. Roller
driving arm 202 is now rotated counter-clockwise to
load position 206 and the reservoir cassette is
removed from the roller pump and discarded. A new
disposable reservoir cassette 30, filled with medica-
tion, is attached to the roller pumpO Since the
reusable injection catheter is filled with medica-
tion, with the first cannula in the patient, it is
not necessary to supply an initial amount of medica-
tion into the catheter. It should be noted that
resilient sleeve 110 prevents medication contained
within the catheter from exiting through the second
cannula when the injection catheter is not attached
to the reservoir cassette~ Before attaching the
injection catheter to the reservoir cassette, the
roller is again advanced to the start position
The medication, displaced by this roller motion,
which is not needed to fill an empty injection
catheter, flows into interior portion 67 of the purge
chamber as depicted in Fig 29. Any gases which may
~5~
P~625
-29-
be present within interior portion 67 are forced out
of the purge chamber through filter 64. The injec-
tion catheter is now connected to the reservoir
cassette and the roller pump timing mechanism acti-
vated to start another medication delivery period.
At the end of this second medication de:Livery period,
it is preferred that the initial catheter be dis-
carded and a delivery period started with a new
injection catheter and a new injection site, although
this step is not necessary.
It is preferred that cassette housing 37 be made
of plastic such as polystyrene, polypropylene and
polyeth~lene. It is also desirable to make upper
housing portion 39 of a transparent plastic such as
polystyrene so that the patient can readily observe
the condition and position of the disposable reser-
v~ir cassette and roller pump components that are
under the upper housing portion. It is also de-
sirable to make the entire housing of a transparent
material so that the components therein can be
readily observed.
Flexible reservoir tube 34 should be constructed
of materials that are compa~ible with the medication
being stored therein and also flexible enough so as
not to require large amounts of roller pump energy to
compress the tube. Thermoplastic materials such as
polyvinylchloride and thermoplastic elastomers and
natural rubber may be used. However, coextruded
materials are preferred since the material comprising
3~ the inner portion of the tube may be selected for a
low moisture vapor transmission rate and for com-
patibility with the medication while the material
- ` ~25~
P-625
-30-
comprising the outer portion may be selected for
softness and lower energy consumption when subject to
compression. When insulin such as ~-100 Regular is
the medication being used, a composite dual material
tube using polyvinylchloride and a polyolefin such as
polyvinylidene chloride is preferred with the poly-
olef in being located at the inner portion of the
reservoir tube and acting as a liner for contacting
the insulin.
Plug 51 of air-permeable, liquid-impermeable
element 35 may be made of plastic such as poly-
ethylene or polypropylene. Air-permeable, liquid-
impermeable membrane 56 can be made of non-woven
polymeric fabrics selected from polytetrafluoro-
lS ethylene, polyester, polyvinylchloride, polypro-
pylene, polyethylene and the like, preferably ranging
in thickness of from about 0.003 to 0.010 inches
~0.08 to 0~25 mm). Such materials as just described
are available from W.L. Gore and Associates, Inc. of
Elkton, Maryland, and are sold as GORE-TE~ membrane
products. The preferred element is polytetrafluoro-
ethylene with a thickness of approximately 0.008
inches ~0.2 mm). Membrane 56 may be attached to plug
51 via the use of adhesive or heat sealing. The plug
may also be made entirely of air-permeable, liquid-
impermeable material such as microporous polypro-
pylene manufactured by Glasrock Products Inc., Porex
Division, Fairburn, Georgia. Air-permeable, liquid-
impermeable filter 64 of purge chamber 36 and
venting member 126 of the alternative embodiment of
the reusable injection catheter may be made of the
same material as membrane 56 discussed hereinabove.
* a trademark
P-625
Cylinder 57 and sealing memt>er 60 of purge
chamber 36 may be constructed of a wide variety of
rigid or flexible materials with elastomeric ma-
terials such as rubber and thermoplatic elastomers
being prQferred. Cylinder 57 and sealing member 60
may be made in one piece or as separate components
held together, for example, by adhesive. Pierce-
able septum 59 may be constructed of a wide variety
of elastomeric materials with rubber and thermo-
plastic elastomers being preferred.
Flexible conduit 101 of the reusable injection
catheter is preferably made of extr~ded polymeric
tubing with polyolefins or polyvinyl chloride being
preferred. The preferred material for first cannula
104 is stainless steel. Connector housing 107 may be
made of a wide variety of rigid materials with
thermoplastic materials such as polypropylene and
poly ethylene being preferred~ Second cannula 105
may be made of stainless steel or of thermoplastic
materials such as polypropylene and polyethylene or
it may be molded as an integral part of connector
housing 107. Resilient sleeve 110 is preferably
made of self-sealing elastomeric material such as
rubber and thermoplastic elastomers. Hold-down
member 114 is preferably made of a moisture vapor
transmissivet water and bacteria barrier material. A
wide variety of medical grade adhesive coatings are
commercially available for achieving adhesive
properties of the hold-down member. A preferred
material for the hold-down member with the adhesive
thereon is a skin patch system manufactured ~y the
Minnesota Mining and Manufacturing Company under the
name Tegaderm.
* a trademark
X? ~;
~5~
P-625
-32-
It is preferred that all elements of the dis-
posable reservoir cassette and the reusable injection
catheter which contact the liquid medication or the
patient, subcutaneously, should be sterile. Ac-
cordingly, materials should also be selected forcompatability with the sterilization process being
used~
Thus, the present invention provides a dis-
posable reservoir cassette which can be inserted into
and removed from a roller pump without removal of the
injection cannula from the injection site and thus
allowing the use of the same injection catheter for
consecutively used reservoirs. The disposable
reservoir cassette which can be purchased by the user
in a pre-filled condition or filled by the user with
a simple inexpensive filling system. Since the
reservoir cassette contains all of the medication to
be delivered to the user, a separate attached reser-
voir is unnecessary. The present invention also
provides a reusable injection catheter with a
resilient sleeve or sealing means at one end thereof
to prevent loss of medication while changing reser-
voir cassettes and a hold-down member at the other
end thereof to secure the subcutaneously placed
injection needle.
