Infusion reservoir and pump system

A totally subcutaneously implantable infusion reservoir and pump system includes a variable capacity reservoir for receiving and storing fluids containing medications for delivery to a catheter which directs the medications to a specific infusion location in the body. A pump and a valving arrangement is interposed between the reservoir and the catheter to facilitate and control the transfer of the medications from the reservoir to the catheter in a safe and efficient manner. In one preferred form, a normally closed first valve is situated between the reservoir and a pump, and a normally closed second valve is situated between the pump and the catheter in a manner such that the pump and valving arrangement defines a portion of a fluid flow conduit between the reservoir and the catheter. The pump and valving arrangement requires at least two deliberate and sequential steps before the medications stored in the reservoir can be transferred to the catheter. As an additional safety feature, an integral flow occluder can be added to the pump and valving arrangement to prevent the emptying of the medications in the reservoir through the catheter into the body when both normally closed valves are opened simultaneously. When the system is used in the treatment of terminally ill patients, the catheter can be placed within the body to direct morphine or other pain killing medications directly into the lateral ventricle of the brain or into the lumbar subarachnoid space.

BACKGROUND OF THE INVENTION 
This invention relates generally to infusion systems for the administration 
of medications and, more particularly, to a refillable and subcutaneously 
implantable infusion reservoir and pump system useful for pain management 
in the treatment of terminally ill patients. 
It has been found in the treatment of many terminally ill patients that the 
administration of various medications over sustained periods of time is 
necessary. For instance, it is often desirable to provide a pain killer, 
such as morphine, to such patients to help them cope with the sometimes 
excruciating pain which accompanies certain diseases. Frequently, 
terminally ill patients experience such extreme pain that hospitalization 
becomes necessary to provide the patient medications at intervals and in 
quantities sufficient to meet the patient's needs. Alternatively, when 
hospitalization is not acceptable, the patient is often required to obtain 
private nursing care. 
Requiring a terminally ill patient to either be hospitalized or to arrange 
for private nursing care can result in substantial burdens being imposed 
upon both the health care system and the patient. Health care facilities 
are increasingly burdened as the demand for hospital bed space increases 
at a rate greater than the growth in available bed space. This burden is 
accentuated when patients, such as terminally ill patients, are 
hospitalized for want of an alternative treatment methodology. Also, the 
diversion of medically trained personnel to deal with the routine infusion 
of medications to terminally ill patients imposes additional burdens on 
the health care system which could be avoided, provided the proper 
technology were available. 
When patients must be confined to a hospital bed or arrange for private 
duty nursing care to receive prescribed medications, the costs involved 
often exceed the financial means of such patients. For example, many 
terminally ill patients cannot afford to pay for the very expensive and 
individualized care which could make the last period of time prior to 
death much more productive and less difficult for the patient and for 
those around him. Indeed, many such patients cannot afford any medical 
care whatsoever and their only available alternative is to forego 
available treatments. Sometimes patients who cannot afford the 
hospitalization or private nursing care required and who cannot tolerate 
the pain involved with a particular disease must be hospitalized at 
society's expense. 
These burdens to the patient, the health care system and to society in 
general have prompted several changes in health care methodology. For 
instance, many physicians have found it desirable to administer prescribed 
medications on an out-patient basis. This out-patient technique has proven 
to be effective in substantially reducing the costs associated in the 
treatment of many types of ailments; however, there have been a number of 
drawbacks which have made such out-patient arrangements less than ideal. 
A typical drawback of out-patient treatment programs includes the 
requirement of frequent visits by the patient with the physician and the 
resultant time and transportation problems. It is generally recognized 
that if the patient could be provided adequate home care for extended 
periods of time, the time between visits with the physician could be 
lengthened. Such extended home care would benefit the physician, as well 
as the patient, in many circumstances by permitting the physician to 
devote more professional time to other important matters. 
Notwithstanding the foregoing, some patients find that receiving regular 
injections of medications over a prolonged period of time is distasteful, 
not to mention painful. Additionally, it has been found that repeated 
injections through the skin into a specific, limited area of the body can 
be harmful to the patient and can sometimes cause problems which could 
become more threatening to the well-being of the patient than the illness 
being treated. Such problems have made necessary the use of alternate 
injection sites, the rotation of injections among alternate injection 
sites, or, at the extreme, the abandonment of medication injections as a 
useful form of treatment. 
Moreover, some substances have been found to traumatize the skin when 
injected, and this has necessitated the use of alternate means for 
introducing such substances into the body. Such alternate introduction 
means have included the use of catheters which are inserted through the 
skin into the body and have a portion which remains extended through the 
patient's skin to provide external access. This and similar infusion 
systems have proven to be undesirable for extended treatment because of 
the risk of infection at the incision site where the catheter extends 
through the skin. 
Accordingly, there has been a need in the medical arts for a system, 
including the appropriate devices, which allows the patient or his loved 
ones to administer required medications in precise quantities while 
minimizing the number of injections required and visits which need be made 
with a physician. Such a system should be constructed for total 
subcutaneous explacement in the body, include appropriate devices to 
prevent the unintended infusion of the medications into the body, and be 
refillable, such as by injection, to permit long term use. The present 
invention fulfills these needs and provides other related advantages. 
SUMMARY OF THE INVENTION 
The present invention resides in an infusion reservoir and pump system 
useful in the administration of medications to patients requiring 
infusions of medications at relatively frequent intervals and over 
extended periods of time. More particularly, the system is useful in the 
administration of pain killers directly into the central nervous system of 
terminally ill patients. In accordance with the present invention, the 
system, which can be totally subcutaneously positioned within the 
patient's body, generally includes a variable capacity reservoir which 
receives and stores the medications to be administered, a catheter which 
can be positioned to direct the medications to a selected portion of the 
patient's body, and a pump and valving arrangement useful for transferring 
the medications from the reservoir to the catheter and for preventing the 
unintended passage of the medications from the reservoir into the catheter 
for delivery to the patient. 
In the illustrated embodiments, the reservoir supports an injection site 
apparatus capable of receiving the medications to be infused into the 
patient by injection. The injection site apparatus includes a self-sealing 
dome and a relatively rigid base which enclose an injection chamber. The 
injection site apparatus cooperates with an adjacent portion of the 
reservoir to permit the injected medications to flow from the injection 
chamber into the reservoir whenever the fluid pressure within the 
injection chamber exceeds the fluid pressure within the reservoir. This 
cooperation between the reservoir and the injection site apparatus also 
prevents the reverse flow of fluid from the reservoir to the injection 
chamber when the fluid pressure within the reservoir exceeds the fluid 
pressure within the injection chamber. 
To control the direction of fluid flow through the system and to prevent 
any unintended infusion of medications into the patient, the illustrated 
embodiments require the fluid exiting the reservoir to flow through a 
one-way valve and a series of normally closed valves forming portions of a 
fluid flow conduit which directs the medications from the reservoir to the 
catheter. The normally closed valves are coactive with a pump to require 
specific and deliberated steps to pump the fluid containing the 
medications through the the system to the catheter for delivery to the 
patient. More specifically, the pump and valving arrangements of the 
illustrated embodiments require a deliberate and sequential, two-step 
procedure to fill and empty a pumping chamber within the pump. This 
procedure makes the inadvertent introduction of the medications into the 
patient highly unlikely. 
To provide this safeguard, a normally closed first valve forms a portion of 
the fluid flow conduit between the reservoir and the pump. This first 
valve must be manually manipulated, as by percutaneous pressure when 
subcutaneously implanted, to permit the fluid medications to pass from the 
reservoir into the pump for filling the pumping chamber. A normally closed 
second valve is situated between the pump and the catheter to require a 
user of the infusion system to similarly manipulate the second valve to 
place the filled pumping chamber in open fluid communication with the 
catheter. 
In one preferred form, the first and second valves are identical and they 
combine with the pump to form a single, integral control assembly unit. 
This control assembly unit forms a portion of the fluid flow conduit 
between the reservoir and the catheter, and the control assembly unit is 
remote from the one-way valve which is located within an outlet aperture 
of the reservoir. The first and second valves utilize flexible and 
resiliently biased valve diaphragms to generally overlie and close a valve 
aperture in each valve. These valve diaphragms can be displaced to uncover 
the valve apertures by applying percutaneous pressure to an overlying 
cover. 
In another preferred form, the first valve provides a flow occluder which 
prevents the medications from exiting the pumping chamber while the first 
valve is opened. This flow occluder is an important safety feature of the 
system because it effectively prevents the emptying of the medications 
stored in the reservoir into the patient when both the first and second 
valves are opened. Also in this latter preferred form, the housings of the 
first and second valves are constructed of a resiliently flexible 
material, and each enclose a rigid valve stem extending through a valve 
passageway. This stem is normally biased to prevent flow through the valve 
passageway unless forceably displaced. Additionally, a one-way valve is 
located adjacent a first valve inlet to minimize fluid compression within 
the fluid flow conduit upstream the pump and also to prevent any fluid 
from exiting the first valve in any manner other than into the pumping 
chamber. 
The catheter can be inserted into any portion of the body, such as the 
lateral ventricle of the brain or, alternately, into the lumbar 
subarachnoid space. In either configuration, the system provides an 
efficient and convenient apparatus and method for the administration of 
medications directly into the central nervous system of terminally ill 
patients. While such catheter placements are presently contemplated 
primarily to enhance the treatment of terminally ill patients, it is 
conceivable that the infusion reservoir and pump system of the present 
invention could be useful in other medical applications; for instance, in 
the administration of insulin to diabetic patients. 
When the system of the present invention is surgically emplaced within a 
patient, it is deemed generally preferable to locate the reservoir near a 
softer area of the body where the skin can be manipulated to allow the 
reservoir to be percutaneously grasped. Typically, the reservoir will be 
located in a position remote from the catheter in the abdominal cavity, 
below the ribs, near a clavicle, or in any other suitable position the 
surgeon may choose. Besides forming a single, integral control assembly 
unit, the pump and valving arrangement can be constructed from separate, 
coactive components, each forming independent portions of the fluid flow 
conduit leading from the reservoir to the catheter. Notwithstanding the 
configuration of the pump and valving arrangement, it is preferable to 
locate each component generally adjacent a boney surface to provide the 
desired resistence to movement when the components are percutaneously 
manipulated. For instance, the pump and valving arrangement could be 
located adjacent a rib, a clavicle or an iliac crest depending on the 
insertion point of the catheter and the preferences of the surgeon. 
Other features and advantages of the present invention will become apparent 
from the following more detailed description, taken in conjunction with 
the accompanying drawings which illustrate, by way of example, the 
principles of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in the drawings for purposes of illustration, the present 
invention is concerned with an infusion reservoir and pump system, 
generally designated by the reference number 10. This infusion reservoir 
and pump system 10 generally comprises a variable capacity reservoir 12 
connected by a fluid flow conduit 14 to a catheter 16 which directs 
medications stored in the reservoir into the patient at a specific 
location. A pump and valving arrangement 18 is also provided to prevent or 
reduce the likelihood of an inadvertent infusion into the patient of 
medications stored in the reservoir 12. 
It is generally deemed preferable that the system 10 be constructed for 
total subcutaneous implantation in the patient and that the variable 
capacity reservoir 12 be refillable by injection. The pump and valving 
arrangement 18 used in the system 10 can be situated between the reservoir 
12 and the catheter 16 to form a portion of the fluid flow conduit 14 and 
the pump and valving arrangement can include one or more normally closed 
valves. Such a system would require fluid containing the medications to 
flow through the pump and valving arrangement 18 before passing into the 
catheter 16, and with the safety and well-being of the patient an 
all-important consideration in the employment of the system 10, this flow 
path requirement can provide the control over the flow of the medications 
which is critical to the system's safe use. Indeed, a pump and valving 
arrangement can be provided which practically eliminates the chance of 
inadvertently infusing more than a very small quantity of medication into 
the patient by requiring specific sequential and deliberate steps to be 
taken before a measured volume of fluid can be pumped through the system 
10. 
For example, to provide this safeguard a normally closed first valve 20 can 
be situated along the fluid flow path between the variable capacity 
reservoir 12 and a pump 22 to form a portion of the fluid flow conduit 14. 
This first valve 20 could be constructed to require manual manipulation, 
as by percutaneous pressure when subcutaneously implanted, to open the 
first valve and permit the fluid containing the medications to pass from 
the variable capacity reservoir 12 into the pump 22. A normally closed 
second valve 24 can be situated between the pump 22 and the catheter 16 to 
require a user of the system 10 to similarly manipulate the second valve 
for placing the pump in open field communication with the catheter. 
Throughout this description and in the accompanying drawings, a prime 
symbol (') is used in connection with the reference numbers to identify 
elements of a second valve 24 and 224 which are functionally identical to 
corresponding elements of a first valve 20 and 220. Accordingly, in one 
preferred form of the present invention, the normally closed first and 
second valves 20 and 24 are functionally the same and they are combined 
with the pump 22 to form a single, integral control assembly unit 26. This 
control assembly unit 26 is situated along the fluid flow path between the 
reservoir 12 and the catheter 16 to form a portion of the fluid flow 
conduit 14. Each valve 20 and 24 includes a flexible and resiliently 
biased valve diaphragm 28 or 28' which generally overlies a valve aperture 
30 or 30' and which can be displaced to open the valve to fluid flow. In 
another preferred form, a control assembly unit 226 includes an integral 
flow occluder 136 which prevents the medications from exiting a pump 222 
and flowing to a second valve 224 while a first valve 220 is open. This 
integral flow occluder 136 adds an important safety feature to the system 
10 because it effectively prevents the emptying of the reservoir 212 
contents into the patient when both valves 220 and 224 are opened. Also in 
this latter preferred form, the valves 220 and 224 are constructed of a 
resiliently flexible material and the valves each house a rigid valve stem 
228 or 228' extending through a valve passageway 230 or 230'. The valve 
stem 228 or 228' is normally biased to prevent flow through the valve 
passageway 230 or 230' unless forceably displaced. 
The infusion reservoir and pump system 10 can substantially reduce the cost 
of treating some illnesses by eliminating the need for constant medical 
attention or by reducing the number of required visits which need be made 
with a physician. For instance, many terminally ill patients experience 
periods of extreme pain which require regular and frequent injections of 
morphine or other pain killing drugs. In many such cases, a patient having 
the system 10 implanted subcutaneously would be able to receive infusions 
of the required medications as needed while reducing the number of 
injections received as well as the number of out-patient visits with the 
responsible physician. The system 10 will also allow many patients to 
escape the confines of a hospital bed where the primary reason for the 
hospitalization is to provide access to the required amounts of 
medications. These benefits are possible because the variable capacity 
reservoir 12 can be sized to safely store a sufficient amount of 
medication to meet the patient's needs for a number of days. 
By interposing the pump and valving arrangement 18 between the variable 
capacity reservoir 12 and the catheter 16 so that the pump and valving 
arrangement forms a portion of the fluid flow conduit 14, the danger of an 
inadvertent infusion of medication to the patient is reduced. Also, the 
overall design of the system 10 increases its utility for physicians and 
patients in that the system can be constructed in a variety of 
configurations for use in many types of different applications. For 
example, in the treatment of terminally ill patients, morphine can be 
injected into the lateral ventricle of the patient's brain 32 (FIG. 1) or 
into the lumbar subarachnoid space 232 (FIG. 5). Additionally, the system 
10 may be used advantageously by patients requiring regular infusions of 
insulin due to diabetes by minimizing the number of injections received. 
Moreover, the inherent safety and utility of the infusion reservoir and 
pump system 10 will permit a patient's family or other loved ones to care 
for the patient in the privacy of the home and, particularly for 
terminally ill patients, make the period of illness much more productive 
and less difficult for the patient and those around him. 
In accordance with the present invention, and as illustrated with respect 
to a first embodiment in FIGS. 1 through 4, the variable capacity 
reservoir 12 comprises a silicone elastomer shell 34 which can expand and 
collapse to accommodate changing volumes of fluid medications. The 
reservoir 12 includes an outlet aperture 36 through the shell 34 and a 
plurality of inlet apertures 38 generally situated through a portion of 
the reservoir shell remote from the outlet aperture. In systems 10 
designed for use in the treatment of terminally ill patients, a reservoir 
12 having a thirty milliliter capacity would normally hold sufficient 
amounts of morphine or other similar pain killing drugs to supply patients 
sufficient quantities of medications for several days. As illustrated in 
FIG. 1, the variable capacity reservoir 12 can be located in a remote 
position from the insertion point of the catheter 16 in any suitable 
position as the surgeon chooses, such as in the abdominal cavity 40, below 
the ribs 42 or near the clavicle 44. Indeed, the reservoir 12 can be 
placed in any soft area of the body 46 which would permit the reservoir to 
be percutaneously grasped while subcutaneously implanted. Attached to the 
reservoir shell 34 are a pair of suture tabs 48 and 50 which permit the 
surgeon to anchor the reservoir 12 at the selected location within the 
patient to prevent migration of the reservoir to an undesirable location. 
An injection site apparatus 52 is provided which overlies the reservoir 
inlet apertures 38 and the adjacent portion of the reservoir shell 34. The 
injection site apparatus 52 includes a rigid base 54 and an overlying 
self-sealing dome 56 which enclose and define an injection chamber 58 
therebetween. The self-sealing dome 56 is constructed of a silicone 
elastomer material, such materials providing acceptable levels of tissue 
reaction when subcutaneously implanted, which can be pierced by a 
twenty-five gauge or smaller needle 60 without affecting the ability of 
the dome to reseal after the needle has been withdrawn. The rigid base 54 
can be constructed of a polypropylene or similar material to provide a 
needle-shield for the reservoir 12. The polypropylene material of the base 
54 has sufficient rigidity to prevent the needle 60 inserted through the 
self-sealing dome 56 from piercing the shell 34 of the reservoir 12 and 
such material also provides acceptable levels of tissue reaction when 
subcutaneously implanted. 
To provide an injection chamber exit passageway through the injection site 
apparatus base 54 and yet prevent the passage of an injection needle 60 
through the base which could damage the underlying reservoir shell 34, the 
injection site apparatus base includes an integral, molded riser 62. This 
riser 62, best illustrated in FIG. 3, includes sidewalls 64 extending 
generally perpendicular to the plane of the base 54 toward the 
self-sealing dome 56, and a solid cap 66 perpendicular to and covering the 
sidewalls. The riser 62 extends from the inner surface of the base 54 into 
the injection chamber 58 to define a sub-chamber 68 between the injection 
chamber and the reservoir shell 34. A plurality of base apertures 70, 
forming needle-shield outlet passageways, are provided through the 
sidewalls 64 to permit medications injected into the injection chamber 58 
to flow into the sub-chamber 68 while simultaneously preventing the needle 
60 from passing through those base apertures and damaging the reservoir 
shell 34. 
Generally surrounding the injection site apparatus base 54 is a flange 72 
of the self-sealing dome 56. The underside of this flange 72 is securely 
attached to the reservoir shell 34 to connect the injection site apparatus 
52 to the reservoir 12 while permitting the portion of the reservoir shell 
adjacent the injection site apparatus base 54 to move relative to that 
base. Importantly, this attachment permits the injection site apparatus 
base 54 to cooperate with the adjacent reservoir shell 34 to transfer 
fluid medications from the injection chamber 58 into the reservoir 12 when 
the fluid pressure within the injection chamber is greater than the fluid 
pressure within the reservoir. 
This fluid transfer is accomplished by positioning the reservoir inlet 
apertures 38 so they lie adjacent the underside of the injection site 
apparatus base 54 at a location removed from the injection site apparatus 
sub-chamber 68. The portion of the reservoir shell 34 adjacent the 
injection site apparatus base 54 is resiliently biased to normally lie 
flat against the injection site apparatus base to form a seal 
therebetween. By connecting the injection site apparatus 52 to the 
reservoir shell 34 at the self-sealing dome flanges 72, the portion of the 
reservoir shell adjacent the injection site apparatus base 54 can flex and 
separate from the injection site apparatus base sufficiently to provide a 
fluid passageway 74 between the sub-chamber 68 and the reservoir inlet 
apertures 38 (FIG. 3). 
When the fluid pressure within the injection chamber 58 increases to a 
point where it exceeds the fluid pressure within the reservoir 12, the 
reservoir shell 34 adjacent the injection site apparatus base 54 flexes to 
separate from the base to permit the fluid to flow from the injection 
chamber through the injection chamber base apertures 70 into the 
sub-chamber 68, and from the sub-chamber through the reservoir inlet 
apertures 38 into the reservoir. After a sufficient amount of fluid 
medications have transferred from the injection chamber 58 to the 
reservoir 12 to equalize their respective fluid pressures, the resiliency 
of the portion of the reservoir shell 34 adjacent the injection site 
apparatus base 54 causes the reservoir shell to again lie flat against the 
underside of the injection site apparatus base. Because the reservoir 
inlet apertures 38 are caused to lie flat against the injection site 
apparatus base 54, the flow of fluid medications from the reservoir 12 
into the injection chamber 58 is prevented even when the fluid pressure 
within the reservoir is greater than the fluid pressure within the 
injection chamber. This unidirectional flow feature provided by the 
cooperation between the injection site apparatus base 54 and the reservoir 
shell 34 provides a safety mechanism for the system 10 which prevents the 
escape of medications stored within the reservoir 12 through the injection 
site apparatus 52. This safety mechanism minimizes problems which could 
occur if medications began to leak through the self-sealing dome 56. 
A one-way valve 76 is situated within the reservoir outlet aperture 36 to 
allow fluid medications to flow from the reservoir 12 while preventing any 
fluids from entering the reservoir through the outlet aperture (FIG. 2). 
The one-way valve 76 includes a rigid encasement 78 which protects and 
supports an internal flexible valve membrane 80. The valve membrane 80 is 
fashioned after the well-known duck-bill or mitre valve, and the 
encasement 78 is preferably constructed of a polypropylene material to 
have sufficient rigidity to protect the valve membrane. The encasement 78 
is integrally attached to a segment of surgical tubing 82 which forms a 
portion of the fluid flow conduit 14 directing the fluid medications from 
the reservoir to the catheter 16 for delivery to the patient. 
A flexible tube 84 having a plurality of tube apertures 86 extends from the 
one-way valve encasement 78 generally rearwardly into the center of the 
reservoir 12. The flexible tube 84 is constructed preferably of a silicone 
elastomer material haing sufficient resiliency to maintain a flexible tube 
fluid passageway 88 through its center for channeling fluid medications 
from the reservoir 12 to the one-way valve 76 notwithstanding a collapse 
of the reservoir shell 34. Specifically, this flexible tube 84 is provide 
to insure the fluid medications will be able to exit the reservoir 12 even 
when the reservoir shell 34 collapses in a manner covering the reservoir 
outlet aperture 36. Such a collapse of the reservoir shell 34 may result 
from an emptying of fluid from the reservoir 12 during use of the system 
10. 
As the fluid medications are transferred from the reservoir 12 through the 
fluid flow conduit 14 to the catheter 16, the medications pass through the 
pump and valving arrangement 18. As illustrated in FIG. 2, the pump and 
valving arrangement 18 comprises an integral control assembly unit 26 
which is attached to the surgical tubing 82 carrying fluid medications 
which have exited the reservoir 12 through the one-way valve 76. The 
control assembly unit 26 forms a portion of the fluid flow conduit 14 
between the reservoir 12 and the catheter 16 and the unit is situated so 
that a unit inlet, which corresponds with a first valve inlet 90, is in 
open fluid communication with the reservoir outlet aperture 36, and a unit 
outlet, which corresponds with a second valve outlet 92', is in open fluid 
communication with a catheter inlet 94. The control assembly unit 26 
includes generally the normally closed first and second valves 20 and 24 
and the pump 22. The pump 22 is interposed in series between the first and 
second valves 20 and 24 so that the fluid medications must flow through 
each component of the control assembly unit 26 before exiting the unit for 
delivery to the catheter 16. The control assembly unit 26 is provided 
suture tabs 96 and 98 which allow the surgeon to anchor the unit in place 
when subcutaneously implanted to insure that it remains in the location 
selected by the physician. 
The first and second valves 20 and 24 are normally closed to fluid flow in 
either direction and when these valves are subcutaneously implanted in a 
patient, they can be opened to fluid flow only when percutaneous pressure 
is selectively applied to the control assembly unit 26. Because 
percutaneous pressure must be applied to the unit 26 to open the valves 20 
and 24 when subcutaneously implanted, it is preferable to locate the unit 
generally adjacent a bone, such as a clavicle 44 or a rib 42. Such a pump 
and valving arrangement 18 reduces the possibility of inadvertently 
infusing more than a small amount of medications into the patient because 
the control assembly unit 26 requires a combination of sequential and 
deliberate steps to pump the fluid medications through the system 10. 
Each normally closed valve 20 and 24 includes a resiliently rigid housing 
100 or 100' attached to an underlying support sheet 102, and a resiliently 
flexible cover 104 or 104'. A lower surface of the housing 100 or 100', 
which is preferably constructed of a polypropylene material, is securely 
attached to the underlying support sheet 102 in a manner creating a lower 
inlet chamber 106 or 106' in open communication with the valve inlet 90 or 
90'. The underlying support sheet 102 can be constructed of any flexible 
material which produces acceptable levels of tissue reaction when 
subcutaneously implanted, such as reinforced silicon sheeting. The cover 
104 or 104', which is preferably constructed of a silicon elastomer 
material, is securely attached to an upper surface of the housing 100 or 
100' in a manner forming an upper outlet chamber 108 or 108' in open 
communication with the valve outlet 92 or 92'. An upper plate 110 or 110' 
of the housing 100 or 100' has the valve aperture 30 or 30' which permits 
the lower inlet chamber 106 or 106' to communicate with the upper outlet 
chamber 108 or 108'. 
The flexible valve diaphragm 28 or 28', which is preferably formed of a 
silicone elastomer material, is supported within the lower inlet chamber 
106 or 106'. The valve diaphragm 28 or 28' is generally constructed to 
form a dome-shaped member seated circumferentially upon the support sheet 
102 in a manner resiliently biasing the valve diaphragm so that it is 
normally positioned over the valve aperture 30 or 30'. This valve 
diaphragm 28 or 28' is provided a plurality of diaphragm apertures 112 or 
112' as well as a diaphragm ridge 114 or 114' which is molded onto the 
upper surface of the valve diaphragm 28 or 28' to engage the upper plate 
110 or 110' in a manner surrounding the valve aperture 30 or 30' to form a 
seal which prevents any fluid flow through the valve aperture. 
Additionally, a knob 116 or 116' is provided on the underside of the cover 
104 or 104' so that the knob is positioned generally directly above the 
valve aperture 30 or 30'. 
The knob 116 or 116' is situated for travel through the valve aperture 30 
or 30' when the cover 104 or 104' is resiliently pressed downwardly, and 
the diameter of the knob is small enough to prevent the occlusion of the 
valve aperture when the knob is pressed therethrough. When enough pressure 
is applied, the knob 116 or 116' causes the valve diaphragm 28 or 28' to 
flex downwardly a sufficient distance to break the valve seal and allow 
fluids to pass through the valve aperture 30 or 30' (FIG. 4). The cover 
104 or 104' and valve diaphragm 28 or 28' are each sufficiently resilient 
to return to their normal configurations and, consequently, close the 
valve 20 or 24 to fluid flow when the deforming pressure is removed from 
the cover. The inclusion of the normally closed valves 20 and 24 in the 
system 10 enhances the system's utility and safety by preventing the flow 
of fluids in either direction through the valves in the absence of direct 
and continuous external pressure. 
The pump 22, which is interposed between the first valve outlet 92 and the 
second valve inlet 90', comprises a floor plate 118 and an overlying crown 
120 which enclose and define a pumping chamber 122. The pumping chamber 
122 preferably has an evacuation capacity of one milliliter, and the crown 
120, which is resiliently biased to generally maintain a dome or 
arch-shape, can be deformed to lie substantially flat against the floor 
plate 118. The volume of the pumping chamber 122 can be customized to 
accommodate various intended uses of the system 10 and the required dosage 
to be infused into the patient per pumping stroke. The pump crown 120 is 
preferably constructed of a silicone elastomer material, and a portion of 
the reinforced silicone sheet 102 forms the pump floor plate 118. By 
constructing the pump crown 120 of a silicone elastomer material, 
medication can be injected, if necessary, directly into the pumping 
chamber 122 and the puncture site will tend to close upon itself and seal 
the pump crown when the needle 60 is removed. 
While the pump and valving arrangement 18 is shown in the exemplary 
drawings as combined to form the single control assembly unit 26, the 
first valve 20, the second valve 24 and the pump 22 may be separately 
constructed to form individual system 10 components which can be connected 
to one another by a conduit such as the surgical tubing 82. 
The catheter 16 is preferably formed of a barium-impregnated silicone 
elastomer material which is radiopaque for detection by X-ray photography. 
The catheter inlet 94 is attached to the second valve outlet 92' by 
sliding frictional engagement over a second valve outlet connector 124 
integrally attached to the second valve 24. Fluid medications exiting the 
second valve outlet 92' immediately enter the catheter inlet 94 and are 
directed by the catheter 16 for infusion into a specific portion of the 
body 46. For example, in the case of terminally ill patients the catheter 
16 can be inserted into the lateral ventricle of the patient's brain 32, 
as illustrated in FIG. 1. When such catheter 16 placement is contemplated, 
a catheter clip 126, as shown in FIG. 2, can be advantageously utilized to 
hold the catheter in place adjacent a burr hole through the skull. 
The pump and valving arrangement 18 requires a two-step procedure to pump 
fluid medications from the reservoir 12 to the catheter 16. Before pumping 
may begin, however, the second valve cover 104' must be depressed to break 
the second valve seal and the pump crown 120 must be subsequently 
flattened to evacuate the pumping chamber 122 (FIG. 4). While the pump 
crown 120 is held in contact with the floor plate 118, the second valve 
cover 104' is released to permit the second valve diaphragm 28' to return 
to its normally closed position and thereby prevent any reverse fluid flow 
through the second valve 24 into the pumping chamber 122. 
After this preparatory step has been completed and after the surgical 
tubing 82 has been primed with fluid medications, the pump 22 can be 
repeatedly transfer measured quantities of fluid from the reservoir 12 to 
the catheter 16 for infusion into the patient. To begin, the first step 
includes the depressing of the first valve cover 104 sufficiently to break 
the first valve seal. This permits fluid medications to flow from the 
first lower inlet chamber 106 through the first valve aperture 30 into the 
first upper outlet chamber 108 and then through the first valve outlet 92 
into the pumping chamber 122. The biasing and resiliency of the pump crown 
120 tends to draw the fluid medications through the first valve 20 to fill 
the pumping chamber 122 until the pump crown has resumed its dome or 
arch-shape. At times where the biasing and resiliency of the pump crown 
120 is not sufficient to cause fluid flow through the system 10, the 
reservoir 12 can be percutaneously palpated to create adequate fluid 
pressure through the fluid flow conduit 14 to completely fill the pumping 
chamber 122. 
After the pumping chamber 122 is filled with fluid medications, the first 
valve 20 is closed by simply releasing the first valve cover 104. This 
allows the resiliently biased first valve diaphragm 28 to again become 
positioned to block fluid flow through the first valve aperture 30. To 
transfer the fluid medications from the pumping chamber 122 through the 
second valve 24 to the catheter 16, the second step requires the second 
valve to be opened by depressing the second valve cover 104' to break the 
second valve seal. Once the second valve is opened, the pump crown 120 can 
be flattened to force substantially all of the fluid contained within the 
pumping chamber 122 through the second valve and into the catheter 16. 
Before releasing the pump crown 120, it is advisable to release the second 
valve chamber 104' to again close the second valve 24 fluid flow. This 
procedure prevents the suction of fluid from the catheter 16 through the 
second valve 24 and back into the pumping chamber 122 which could result 
from the natural tendency of the pump crown 120 to assume its dome or 
arch-shape. 
It is evident from the foregoing that the sequential two-step pumping 
procedure prevents the inadvertent infusion of medications through the 
system 10 which could result in harm to the patient. The two-step 
procedure provides a safeguard for the system 10 even against 
indiscriminate application of percutaneous pressure to the control 
assembly 26. This infusion reservoir and pump system 10 can greatly ease 
the burden of medical personnel and hospital facilities by providing means 
for internally storing a large quantity of medication which is to be 
administered to a patient over an extended period of time. Various 
apparatuses can be added to the system 10 for a multitude of purposes, 
such as the provision of a burr hole reservoir situated adjacent the skull 
to facilitate injection of medications directly into the brain 32 while 
bypassing the pump and valving arrangement 18 of the system. 
These foregoing features are enhanced and magnified in a second embodiment 
of the invention, illustrated in FIGS. 5 through 8, wherein functionally 
equivalent components common to the first and second embodiments are 
referred to in the drawings by corresponding reference numbers increased 
by two hundred. Generally, the second embodiment includes a variable 
capacity reservoir 212, an injection site apparatus 252 and a flexible 
tube 284 identical to the reservoir 12, the injection site apparatus 52 
and the flexible tube 84 described in connection with the previous 
embodiment, with the exception that an integral reservoir outlet connector 
128 is formed within the reservoir outlet aperture 236 rather than the 
one-way valve 76. The integral reservoir outlet connector 128 is designed 
to engage an inlet end of a segment of surgical tubing 282 to place the 
reservoir outlet aperture 236 in open fluid communication with the 
surgical tubing. This is accomplished by slidably inserting the reservoir 
outlet connector 128 into the inlet end of the surgical tubing 282 in a 
manner forming a friction seal between the reservoir outlet connector and 
the surgical tubing. 
The second embodiment of the infusion reservoir and pump system 10 is very 
similar to the system described in connection with FIG. 2 in that both 
systems can be totally subcutaneously implanted within the patient and 
fluids can be injected into each injection site apparatus 52 and 252 to 
refill the attached variable capacity reservoir 12 and 212. In the second 
embodiment, the fluid medications flow from the reservoir 212 through the 
surgical tubing 282 to the pump and valving arrangement 218. The pump and 
valving arrangement 218 is constructed to form an integral control 
assembly unit 226 comprising a one-way valve 276 located within a normally 
closed first valve inlet 290, a normally closed first valve 220, a 
normally closed second valve 224, and a pump 222 interposed between the 
first and second valves. The first valve inlet 290 forms a control 
assembly unit inlet and a second valve outlet 292' generally corresponds 
with a control assembly unit outlet. From the second valve outlet 292', 
the fluids flows directly into a catheter 216 which can direct the fluid 
medications as described with respect to the catheter 16 of the first 
embodiment. 
The locations of the individual components of the system 10 illustrated in 
FIGS. 5 through 8 should be selected by the surgeon as described in 
connection with the system components of the first embodiment. For 
example, when the catheter 216 supplied is intended to be inserted into 
the lumbar subarachnoid space 232, the surgeon will typically prefer to 
situate the control assembly unit 226 generally adjacent the iliac crest 
130 to provide the desired backing support of a boney surface. The 
reservoir 212 and the injection site apparatus 252 will normally be 
situated in a soft portion of the body 46, typically near the rib cage 42, 
where the injection site apparatus is easily accessible for refilling the 
reservoir by injection. The control assembly unit 226 is situated between 
the reservoir outlet aperture 236 and the catheter inlet 294 to form a 
portion of the fluid flow conduit 214 and to provide positive control over 
the flow of medications through the system 10. To anchor the reservoir 212 
and the injection site apparatus 252, a pair of reservoir suture tabs 248 
and 250 are provided, and similarly, to anchor the control assembly unit 
226 at a desired location, a pair of unit suture tabs 296 and 298 are 
provided. 
As shown in FIG. 7, the control assembly unit 226 comprises generally an 
underlying reinforced silicone sheet 302 forming a unit base which 
supports a first sub-unit 132 including the one-way valve 276, the 
normally closed first valve 220 and the pump 222, and a second sub-unit 
134 including the normally closed second valve 224. The first sub-unit 132 
also includes an integral flow occluder 136 which automatically prevents 
any fluid transfer between a pumping chamber 322 and the second valve 224 
when the first valve 220 is open. The one-way valve 276 is situated within 
the first valve inlet 290 to prevent the backflow of fluid medications 
from the first valve 220 into the surgical tubing 282. 
As best illustrated in FIG. 8, the first sub-unit 132 includes a 
resiliently flexible first housing 138 attached to and overlying the 
reinforced sheet 302. The first housing 138 can be constructed of a 
silicone elastomer material in a manner permitting the first housing to 
reseal if punctured by a needle. A first housing inlet generally 
corresponds to the first valve inlet 290 and the unit inlet, and the first 
housing inlet internally receives and is fused to an outlet end of the 
surgical tubing 282 carrying fluid from the reservoir 212. Fluid flowing 
through the first housing inlet 290 initially enters a first lower inlet 
chamber 306 formed between the first housing 138 and the reinforced sheet 
302. Fluid within the first inlet chamber 306 must await the opening of 
the first valve 220 before flowing into the pump 222. A first upper outlet 
chamber 308, which is in open fluid communication with the pump 222, is 
provided within the first housing 138. A portion of the first upper outlet 
chamber 308 is situated to generally overlie the first lower inlet chamber 
306 so that a first valve passageway 230 through an intermediate portion 
140 of the first housing 138 can provide a fluid flow path between the 
first lower inlet chamber and the first upper outlet chamber. The 
intermediate portion 140 of the first housing 138 generally surrounding 
this valve passageway 238 has a lower tapered surface which forms a first 
valve seat 142. 
A generally T-shaped first valve stem 228 is provided within the first 
valve passageway 230 extending from the first upper outlet chamber 308 
through the first valve passageway and into the first lower inlet chamber 
306. This first valve stem 228 includes an upper expanded section 144 
which is securely attached to an upper ceiling of the first upper outlet 
chamber 308 in a manner causing the first valve stem to move in response 
to any movement of that upper ceiling surface. The first valve stem 228 
also includes a shaft 146 which extends downwardly from the upper expanded 
section 144 through the first valve passageway 230 and into the first 
lower inlet chamber 306 where this shaft enlarges slightly to form a first 
lower tapered foot 148 having a shape which cooperates with the taper of 
the first valve seat 142. In the normally closed position, as illustrated 
in FIG. 8, this first lower foot 148 contacts the first valve seat 142 to 
seal the first valve passageway 230 and prevent fluid flow between the 
first lower inlet chamber 306 and the first upper outlet chamber 308. The 
first upper outlet chamber 308 is also sufficiently large to accommodate 
movement of the upper expanded section 144 of the first valve stem 228 and 
still permit fluid flow therethrough. The first valve stem 228 is 
constructed of a material different from the material of the first housing 
138 to reduce valve seat to valve stem sticking. For instance, the first 
valve stem 228 can be constructed of a polypropylene material to reduce 
the possibility of sticking to a silicone elastomer first valve seat 142 
during storage, handling, shipping or use of the first valve 220. 
The pumping chamber 322 is defined by an enlarged void created within the 
first housing 138. The first housing 138 provides the pump 222 with a 
resiliently flexible overlying crown 320 which can be manipulated by 
external pressure to flatten the crown against a pump floor 318 to cause 
evacuation of the pumping chamber 322. The pump floor 318 includes a 
needle-guard 150 which prevents a needle tip, which may be inserted 
through the pump crown 320, from passing through the pump floor. 
The first housing 138 also includes a first housing outlet 152 which forms 
a pump outlet passageway generally overlying the first upper outlet 
chamber 308. This first housing outlet 152 is in open communication with a 
control assembly unit connector tube 154 which directs the fluid exiting 
the first housing 138 to a second housing inlet 290'. The connector tube 
154 is integrally attached to the first housing 138 at a first housing 
outlet port 156 and to the second sub-unit 134 a second housing inlet port 
158. 
Situated within the first housing outlet 152 between the pumping chamber 
322 and the first housing outlet port 156 is the integral flow occluder 
136 which generally includes a pair of spaced apart, cooperating boots 160 
which, when pressed together, prevent fluid flow through the first housing 
outlet. This flow occluder 136 is positioned directly above the first 
valve stem 228 along its longitudinal axis, the first lower inlet chamber 
306, the first valve passageway 230, and the first upper outlet chamber 
308. 
As illustrated in FIG. 8, when the first valve 220 is in its normally 
closed configuration, fluid cannot pass from the first lower inlet chamber 
306 to the first upper outlet chamber 308 because a seal is formed between 
the first lower foot 148 and the first valve seat 142. The pumping chamber 
322 is in open fluid communication with the first housing outlet port 156 
through the first housing outlet 152 because the cooperating boots 160 of 
the integral flow occluder 136 are spaced to permit fluid flow 
therethrough. This configuration is maintained by natural resiliency and 
biasing constructed into the first housing 138. When external pressure is 
applied downwardly to the first housing 138 at a point overlying the first 
valve 220, as illustrated by the arrow 162 in FIG. 7, a first housing 
upper cover 304 is forced downwardly to cause the boots 160 of the flow 
occluder 136 to meet and close the first housing outlet 152 to fluid flow. 
Furthermore, as the downward pressure on the first housing upper cover 304 
is increased, the upper ceiling of the first upper outlet chamber 308 is 
deformed and moved downwardly, causing an equivalent downward movement of 
the first valve stem 228. As the first valve stem 228 is moved downwardly, 
the seal between the first lower foot 148 and the first valve seat 142 is 
broken, placing the first lower inlet chamber 306 in open fluid 
communication with the first upper outlet chamber 308. 
This construction of the first housing 138 to include the flow occluder 136 
adds an important safety feature to the infusion reservoir and pump system 
10 because there can never be more than the volume of fluid contained 
within the pumping chamber 322 which can pass from the first sub-unit 132 
to the second sub-unit 134 each time the first valve seal is broken. 
Whenever the first valve 220 is opened, the flow occluder 136 blocks the 
first housing outlet 152 to fluid flow and thus prevents any fluid 
medications from exiting the pumping chamber 322 and flowing to the second 
valve 224. With the fluid flow conduit 214 so blocked, the second valve 
224 can be simultaneously opened with the opening of the first valve 220 
without placing the reservoir 212 in open communication with the catheter 
216 and risking an excessive transfer of medications through the system 
10. 
The second sub-unit 134 is functionally and structurally very similar to 
the first sub-unit 132 with the exception that it is simplified to include 
only the normally closed second valve 224. The second sub-unit 134 
comprises a resiliently flexible second housing 164 generally overlying 
the reinforced sheet 302. The second housing 164 forms a second lower 
inlet chamber 306' and an overlying second upper outlet chamber 308' which 
communicate with each other through a second valve passageway 230' in a 
manner very similar to that described in connection with the first 
sub-unit 132. A second valve stem 228', which is identical to the first 
valve stem 228, is provided to form a second valve seat between a second 
lower foot 148' and a second valve seat 142' in a manner similar to that 
described in connection with the first valve 220. In fact, the second 
valve 224 is structurally the same as the first valve 220. 
The second lower inlet chamber 306' is in open communication with the 
second housing inlet 290' which, in turn, is in open fluid communication 
with the connector tube 154. Forming a portion of the second upper outlet 
chamber 308' is an integral outlet connector 324 which defines the control 
assembly unit outlet. As was the case with the first valve 220, the 
natural resiliency and biasing of the second housing 164 holds the second 
valve 228' in a position where the second lower foot 148' interacts with 
the second valve seat 142' to prevent fluid flow through the second valve 
passageway 230'. The second valve seal can be broken by applying downward 
pressure to a second housing upper cover 304' of the second housing 164 
with sufficient force to cause the downward movement of the second valve 
stem 228' through the second valve passageway 230' to break the second 
valve seal. When the second valve seal is broken, the second lower inlet 
chamber 306' is placed in open fluid communication with the second upper 
outlet chamber 308'. 
The reinforced sheet 302 underlying the first and second housings 138 and 
164 is sufficiently flexible to facilitate positioning of the control 
assembly unit 226 within the body 46 to follow the body's natural 
contours. The first and second housings 138 and 164 are separately 
attached to the reinforced sheet 302 and they are structurally independent 
of one another to also further enhance this contouring quality of the 
control assembly unit 226. In a manner similar to that described in 
connection with the previous embodiment, the first and second sub-units 
132 and 134 could easily be separated for individual placement within the 
patient. All that would be required to effect such a separation would be 
to lengthen the connector tube 154 which channels the fluid medications 
from the first housing outlet port 156 to the second housing inlet port 
158. 
The catheter 216 illustrated in FIG. 6 is identical to the catheter 16 
previously described and illustrated in FIG. 2. The catheter clip 326 
illustrated is useful for positioning the catheter 216 when it is inserted 
into the lateral ventricle of the patient's brain 32, and this catheter 
clip can be deleted, for example, when the system 10 is to be used to 
infuse medications into the lumbar subarachnoid space 232 (FIG. 5). 
To transfer medications from the reservoir 212 to the catheter 216, the 
control assembly unit 226 requires a two-step procedure to be followed. 
Before this two-step procedure can begin, however, the pumping chamber 322 
must be evacuated of all fluids in a manner causing the pumping crown 320 
to be flattened against the needle-guard 150. The surgical tubing 282 
connecting the reservoir 212 to the first sub-unit 132 must also be primed 
with the fluid medications. 
Once these preliminary tasks have been accomplished, the first step of the 
pumping procedure can be initiated by depressing the first housing upper 
cover 304 overlying the first valve 220 in the direction indicated by the 
arrow 162 in FIG. 7. Such depression of the first housing cover 304 causes 
the integral flow occluder 136 to block the escape of fluid from the 
pumping chamber 322 to the first housing outlet port 156, and the downward 
movement of the first valve stem 228 breaks the first valve seal allowing 
fluid to pass from the first lower inlet chamber 306 to the first upper 
outlet chamber 308 and into the pumping chamber 322. The natural 
resiliency of the pump crown 320 tends to draw fluid through the first 
valve 220 as the pumping chamber 322 expands until the pump crown 320 has 
attained its natural dome or arch-shape. Throughout this first step the 
fluid medications are restricted to flowing past the one-way valve 276, 
through the first valve 220 and into the pumping chamber 322. 
After the pumping chamber 322 has been filled with the fluid medications, 
the external downward pressure exerted upon the first housing upper cover 
304 is released. This removal of downward pressure allows the natural 
resiliency and biasing of the first housing 138 to move the first valve 
stem 228 upwardly to close the first valve 220 and also to space the boots 
160 of the flow occluder 136 to place the pumping chamber 322 in open 
fluid communication with the second housing inlet 290'. 
To begin the second step of the pumping operation, the second housing upper 
cover 304' is pressed downwardly to break the second valve seal. After the 
second valve seal has been broken, the pumping chamber 322 can be 
evacuated through the first housing outlet 152 by simply depressing the 
pump crown 320 downwardly until it is flattened against the needle-guard 
150. The fluid medications contained within the pumping chamber 322 will 
flow through the first housing outlet 152 past the spaced apart boots 160 
of the flow occluder 136 and into the connector tube 154 which carries the 
medications to the second housing inlet port 158. From the second housing 
inlet port 158, the fluid medications flow into the second lower inlet 
chamber 306', through the second valve passageway 230' past the second 
valve stem 228', and into the second upper outlet chamber 308' where the 
fluid is placed in open fluid communication with the catheter 216. 
After the pumping chamber 322 has been so evacuated, it is generally deemed 
preferable to sequentially remove the pressure exerted on the second 
housing cover 304' to allow the second valve 224 to reseal and then 
release the downward pressure on the pump crown 320. This sequence is 
preferable because if the pump crown 320 was released prior to closing the 
second valve 224, the natural resiliency and biasing of the pump crown 
would tend to suck fluid from the catheter 216 through the second valve 
back into the pumping chamber 322 as the resilient pump crown resumed its 
natural arch or dome-shape and the volume of the pumping chamber expanded. 
The flow occluder 136 of the control assembly unit 226 greatly enhances the 
utility and safety of the system 10 because even if both normally closes 
valves 220 and 224 were simultaneously opened, there would be no 
inadvertent infusion of medication into the patient. The natural 
resiliency of the first and second housings 138 and 164 causes the first 
and second valve stems 228 and 228' to form seals sufficiently strong to 
prevent flow in either direction through the first and second valves 220 
and 224. However, if the first and second housings 138 and 164 were 
constructed of a material having less than ideal natural resiliency, a 
hole could be provided in the bottom of each valve stem 228 and 228' which 
could position a spring and plunger arrangement which would interact with 
the reinforced sheet 302 to enhance the tendency of the valve stems to 
move upwardly. Also, it is deemed generally preferable that the system 10 
be constructed with as few connections as possible to minimize the 
possibility of leakage through the fluid flow conduit 214. 
It is evident from the foregoing that both disclosed embodiments of the 
infusion reservoir and pump system 10 can be beneficially used by patients 
to reduce medical costs associated with the treatment of illnesses 
requiring frequent injections. Various apparatuses can be added to the 
systems 10 without detracting from their basic utility. Also, it is 
evident that the systems 10 provide means for safely and efficiently 
transferring measured quantities of medications simply through 
percutaneous palpation of the pump and valving arrangements 18 and 218. 
Although two particular embodiments of the invention have been described in 
detail for purposes of illustration, various modifications may be made to 
each without departing from the spirit and scope of the invention. 
Accordingly, the invention is not to be limited, except as by the appended 
claims.