U.S. patent application number 10/677718 was filed with the patent office on 2004-04-01 for apparatus and method of intravenous fluid infusion.
Invention is credited to Peterson, Dean McCormack.
Application Number | 20040064097 10/677718 |
Document ID | / |
Family ID | 24269361 |
Filed Date | 2004-04-01 |
United States Patent
Application |
20040064097 |
Kind Code |
A1 |
Peterson, Dean McCormack |
April 1, 2004 |
Apparatus and method of intravenous fluid infusion
Abstract
An infusion system packaged in a light weight nylon portable
mesh container, which is also the pump of the system, includes a
removable therapy bag holding the Rx to be infused into the
patient. A bladder within the pump is inflatable to provide
pressure onto the therapy bag to aid in the discharge of the Rx.
When filling the therapy bag, the pharmacist, using his computer to
comply with standards, simultaneously programs an EPROM with data
specifying the Rx as well as instructions for dispensing the Rx. In
one embodiment of the invention, the EPROM fits into a docking
receptacle in the pump, while in a second embodiment the EPROM is
integral with the therapy bag. A microcomputer mounted in the pump
is programmed to control the flow of the Rx to the patient, reading
the data from the EPROM in generating the control signals. The
microcomputer cyclically drives a fluid control module which
outputs a fixed amount of Rx for each cycle of operation. Three
fluid control modules are disclosed; a cavity which deliver a bolus
of Rx for each rotor rotation, or a shuttling longitudinally
displaceable "cork" positioned in the output connector of the
therapy bag, or a squeezed tube. Flow is monitored, and alarm
interrupts to the microcomputer are provided for flow failure
generating appropriate alarms. An alarm shuts down system operation
and alerts the patient by means of visual messages on the
microcomputer display and by an audible alarm. A buffer memory in
the pump stores data relevant to such a mishap for later
examination to determine responsibility and cause. Data is tied to
a real-time clock (date and time).
Inventors: |
Peterson, Dean McCormack;
(Escondido, CA) |
Correspondence
Address: |
Schwegman, Lundberg, Woessner & Kluth, P.A.
P.O. Box 2938
Minneapolis
MN
55402
US
|
Family ID: |
24269361 |
Appl. No.: |
10/677718 |
Filed: |
October 2, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10677718 |
Oct 2, 2003 |
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09567966 |
May 10, 2000 |
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6641562 |
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Current U.S.
Class: |
604/132 ;
604/251 |
Current CPC
Class: |
A61M 5/148 20130101;
A61J 2200/70 20130101; A61M 2205/50 20130101; A61J 1/05 20130101;
A61M 2205/60 20130101; A61M 5/14244 20130101; A61J 2205/60
20130101 |
Class at
Publication: |
604/132 ;
604/251 |
International
Class: |
A61M 037/00 |
Claims
What is claimed is:
1. A therapy infusion apparatus for delivery of therapeutic fluid
to a patient, said apparatus comprising: a) a flexible therapy bag,
b) a movable surface which can apply force to an outside surface of
said therapy bag to increase fluid pressure within said therapy
bag, c) an exit port in said therapy bag which will allow fluid to
exit in a delivery direction from said flexible therapy bag under
pressure, d) an adjustable, fluid control element located along
said deliver direction, after said exit port.
2. The therapy infusion apparatus of claim 1 wherein said therapy
bag has at least one major face which comprises at least 25% of the
total surface area of said therapy bag, and said movable surface
can be moved into contact with said at least one major surface so
that contact between said at least one major surface and said
movable surface covers at least 50% of the surface area of said at
least one major surface by the time that said movable surface is
fully extended.
3. The therapy infusion apparatus of claim 1 wherein said therapy
bag comprises at least two fluid flow ports within a fluid control
element, one of said ports comprising said exit port, and adjacent
to at least one of said ports is an element which has a storage
area for a memory unit and access ports for accessing information
from said memory unit.
4. The therapy infusion apparatus of claim 3 wherein said memory
unit comprises a chip, and the access ports enable electronic
connection from an outside memory reading or memory writing
apparatus to said chip.
5. The therapy infusion apparatus of claim 4 wherein a chip is
present within said storage area, and said chip contains
electronically readable information relating to at least two
different topics of information selected from the group consisting
of a prescription for the therapeutic material; the name of an
active ingredient in the prescription; the chemical name of a
prescription carrier; additives in the prescription; volume of the
prescription; expiration date; name of a prescribing doctor; name
of a private loader; name of a local supplier/manufacturer of
ingredients of the prescription; source of at least some materials
in the prescription; a name of a therapy bag manufacturer; a name
of a pharmacist; a patient name; patient information relating to at
least one of age, allergies, address, frequency of prescription
refill, weight, chemical intolerances, instructions for a flow
control module with respect to desired flow rates; intervals for
delivery; rate and volume of delivery; and drip rate.
6. The therapy infusion apparatus of claim 1 wherein said movable
surface comprises an extendable bladder.
7. The infusion apparatus of claim 6 wherein said bladder is
expandable or inflatable by a liquid to move a surface of the
bladder against a surface of the therapy bag.
8. A therapy bag for use in the infusion of liquids to a patient
comprising a flexible bag having a storage area and a delivery end,
said delivery end comprising at least two fluid ports, at least one
port capable of allowing fluid from within said storage area when
pressure is applied to liquid within said storage area, and said
delivery end also having a storage area for storage of a memory
element, said storage area having access ports for electronically
accessing said memory element.
9. The therapy bag of claim 8 wherein said storage area contains a
chip and there are electronic access ports oriented in said storage
area to allow external electronic access to said chip so that
information on said chip may be accessed.
10. The therapy bag of claim 9 wherein said storage area is
asymmetrically located along said delivery end.
11. The therapy bag of claim 10 wherein at least two liquid flow
ports are located to one side of said asymmetrically located
storage area.
12. The therapy bag of claim 9 wherein said chip contains
electronically readable information relating to at least two
different topics selected from the group consisting of the
prescription; the name of an active ingredient in the prescription;
the chemical name of a prescription carrier; additives in the
prescription; volume of the prescription; expiration date; name of
a prescribing doctor; name of a private loader; name of a local
supplier/manufacturer of ingredients of the prescription; source of
at least some materials in the prescription; a name of a therapy
bag manufacturer; a name of a pharmacist; a patient name; patient
information relating to at least one of age, allergies, address,
frequency of prescription refill, weight, chemical intolerances,
instructions for a flow control module with respect to desired flow
rates; intervals for delivery; rate and volume of delivery; and
drip rate.
13. The therapy bag of claim 10 wherein said chip contains
electronically readable information relating to at least two
different topics selected from the group consisting of the
prescription; the name of an active ingredient in the prescription;
the chemical name of a prescription carrier; additives in the
prescription; volume of the prescription; expiration date; name of
a prescribing doctor; name of a private loader; name of a local
supplier/manufacturer of ingredients of the prescription; source of
at least some materials in the prescription; a name of a therapy
bag manufacturer; a name of a pharmacist; a patient name; patient
information relating to at least one of age, allergies, address,
frequency of prescription refill, weight, chemical intolerances,
instructions for a flow control module with respect to desired flow
rates; intervals for delivery; rate and volume of delivery; and
drip rate.
14. The therapy bag of claim 10 wherein a battery is also present
on said therapy bag.
15. The therapy bag of claim 14 wherein said battery provides power
at least to the chip.
16. The therapy bag of claim 10 wherein said battery provides power
to at least one electrically powered element on said therapy bag
selected from the group consisting of a display panel on said
therapy bag, a chip, a fluid rate control element, vibratory
signal, liquid emitting diode display, and a sound alarm.
17. The therapy infusion apparatus of claim 1 further comprising e)
a fluid flow detector that determines at least whether therapeutic
fluid is flowing through, towards or past the exit port.
18. The therapy infusion apparatus of claim 1 further comprising f)
a meter measuring flow rates of the therapeutic liquid within or
out of said therapy infusion apparatus.
19. The therapy infusion apparatus of claim 1 further comprising g)
an alarm that activates upon malfunctioning or interruption of any
defined function of the therapy infusion apparatus during loading
of a therapy bag or delivery of therapeutic liquid to a patient or
movement of therapeutic liquid within the therapy infusion
apparatus.
20. The therapy infusion apparatus of claim 1 further comprising a
microcomputer for controlling at least one operating function of
said infusion apparatus.
21. The therapy infusion apparatus of claim 4 wherein a memory chip
in said infusion therapy apparatus is programmable by an auxiliary
computer external to said infusion apparatus, whereby information
may be entered for storage in said chip relating to said
therapeutic fluid.
22. The therapy infusion apparatus of claim 2 whereby said a pump
is present within said apparatus which pump comprises: a) flexible
enclosure member wherein the elements comprising said infusion
apparatus are mounted, b) a bladder located in said pump, wherein
when said therapy bag is positioned in said pump the surfaces of
said therapy bag are substantially in contact with said bladder, c)
air compressor for inflating said bladder, d) pressure transducer
for measuring the air pressure in said bladder, and e) a vent for
controllably venting said bladder.
23. The apparatus of claim 2 wherein further comprising a meter
measuring quantities of therapeutic fluid and said meter comprises:
a) a shell having an interior cavity, said cavity having an input
port for accepting said medicinal fluid from said therapy bag and
an output port for transferring said medicinal fluid out to said
patient, b) first and second axles parallelly mounted in said
cavity, c) first and second longitudinally extending rotors, d)
first and second fixed bar magnets mounted with the axes of said
magnets directed along the longitudinal axis of said first rotor,
said first rotor having a first cycloidal contour, e) third and
fourth fixed bar magnets mounted with the axis of said magnets
directed along the longitudinal axis of said second rotor, said
second rotor having a second cycloidal contour, said first and said
second rotors rotatably mounted on said first and said second
axles, wherein said longitudinal axis of said first rotor is
perpendicular to said longitudinal axis of said second rotor, and a
portion of said first cycloidal contour is substantially in contact
with a portion of said second cycloidal contour, g) said shell
having an interior wall in the shape of a continuous closed curved
surface, h) said first rotor having a portion of its contour in
contact with said wall, said second rotor having a portion of its
contour in contact with said wall, wherein a first chamber is
formed bounded by said first rotor said second rotor and said wall,
and a second chamber is formed bounded by said first rotor said
second rotor and said wall, said first chamber containing said
inlet port and said second chamber containing said outlet port, i)
a reciprocating shuttle proximate said shell, said shuttle
comprising movable fifth and sixth magnets, said fifth magnet for
interaction with said first and second magnets when said shuttle is
actuated to position said fifth magnet to attract said first or
said second magnet allowing rotation of said first and said second
rotors, and said sixth magnet for interaction with said third and
said fourth magnets when said shuttle is actuated to position said
sixth magnet to attract said third or said fourth magnet allowing
rotation of said first and said second rotors, whereby for each
quarter rotation of said first and said second rotors a fixed
quantity of medicinal fluid is forced from said second chamber
through said outlet port, and j) electromagnetic actuating means
for alternately driving said shuttle back and forth, said
electromagnetic actuating means under control of said
microcomputer.
24. The infusion apparatus of claim 23 wherein said outlet port
includes a check valve opposing fluid flow back into said
cavity.
25. The infusion apparatus of claim 18 wherein said meter comprises
a rate of magnetic field change electrical transducer.
26. The infusion apparatus of claim 1 wherein and alarm system is
activated by a microcomputer responsive to a fluid flowing through
said meter.
27. The infusion apparatus of claim 26 further comprising either h)
a display driven by said microcomputer, said display visually
indicating any defined apparatus malfunction, or b) an audio system
driven by said microcomputer aurally indicating any defined
apparatus malfunction.
28. The therapy infusion apparatus of claim 27 further comprising:
d) alarm information available from said microcomputer as input to
a modem for transmission over an external communication line.
29. A method of infusing a medicinal fluid to a patient, comprising
the steps of: a) filling a therapy bag with said medicinal fluid,
b) recording on a semiconductor EPROM the characteristics of said
fluid and the necessary information related to infusing a patient
with said fluid, c) reading said information from said EPROM by a
microcomputer, d) generating control signals in accordance with
said information by said microcomputer, and e) activating a fluid
dispensing unit in response to said control signals, whereby said
fluid dispensing unit infuses said patient with said medicinal
fluid through set tubing in accordance with said recorded
information.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to administration of a medicinal
fluid to a patient and, in particular, to low-cost, easy-to-use
infusion systems for the intravenous dispensing of a fluid
prescription.
[0003] 2. Description Relative to the Prior Art
[0004] A wide variety of infusion systems are presently known in
the medical art, particularly within the field of technology
directed towards therapies requiring the use of intravenous
medication. The administration of medication by intravenous
delivery as prescribed by a medical doctor may be dispensed to the
patient by an infusion system for certain therapies. The prescribed
therapeutic liquid is referred to as the prescription or "Rx", and
is usually supplied by a pharmacist in a container such as a
disposable plastic bag for use with an infusion system. The plastic
bags usually have attached to them various components or elements
which are useful in the infusion process such as various tubes and
elements to secure the bag in place, to transport liquids (e.g.,
prescriptions, water, nutritional supplements, analyze solutions,
etc.) with respect to the patient, to support the elements of the
container, etc. This composite arrangement is usually referred to
in the medical art as a "set". The set is then loaded into a fluid
delivery device called the "pump" either by a nurse or by the
patient himself. Once the pump is connected to the patient, the
device pumps the Rx through the conveying tubes of the set to
infuse the patient.
[0005] The assembly of an infusion system, as presently known in
the art, requires a certain degree of skill and manual dexterity.
In some conventional infusion systems, the tubing of the set must
be loaded into the pump, the set cleared, the set tubing meshed
between rollers, and the roller gate closed. In a hospital setting,
a nurse or medical technician is generally available to perform
these dexterous steps and to instruct and/or supervise the patient
in the loading and operation of the pump. It is also necessary for
the physician, nurse or patient to program the rate of pump
operation to control the fluid flow rate of the medication to the
patient. Written records of the infusion system parameters must be
generated and maintained for various medical reporting reasons. In
the present day medical setting, many ill people are out-patients
who must set up and operate their infusion system at home without
the services of a knowledgeable practitioner to oversee proper
assembly and performance of the system. Some patients may have
debilitating illnesses or impacted conditions of memory dysfunction
which leave them too weak or too forgetful to carry through complex
assembly and programming procedures. With a rapidly growing aging
population, many out-patient seniors may not have either the manual
dexterity, physical strength, or mental acuity needed to cope with
the demands of setting up and using current infusion systems.
Additionally, with the downward economic pressures on all medical
costs, and especially those of Medicare and Medicaid, a need exists
for reducing the costs of these therapeutically essential infusion
systems and minimizing the cost of technical assistance
personnel.
[0006] U.S. Pat. No. 5,935,099 describes a menu driven
reprogrammable drug pump is provided with a memory, such as flash
memory, a display, a keyboard, and a communications port to allow a
generic pump to be programmed with a desired pump application
(therapy) program and patient specific settings. Programming and
data transfer with another pump or a computer to and from the
patient pump is by the communications port that allows local and/or
remote communications with the pump. Flash memory stores the pump
application program during use. Patient safety is provided by a
cassette identification system, an occlusion detection system, and
a latch/lock detection system. Automated testing of the pump is by
a closed loop testing system. This system does not provide for
unique pump identification, in combination with unique patient and
therapy information. A limited range of pumping systems is also
disclosed.
[0007] The present invention alleviates problems present in the
prior art by providing a simplified, low-cost infusion system
adapted for use both by in-patients in hospitals and by
out-patients at home.
SUMMARY OF THE INVENTION
[0008] A therapy infusion apparatus for delivery of medicinal fluid
to a patient may comprise:
[0009] a) a flexible therapy bag,
[0010] b) a movable surface which can apply force to an outside
surface of the therapy bag to increase fluid pressure within said
therapy bag,
[0011] c) an exit port in the therapy bag which will allow fluid to
exit in a delivery direction from the flexible therapy bag under
fluid pressure,
[0012] d) an adjustable, fluid control element located along the
delivery direction, after the exit port.
[0013] The therapy infusion apparatus may be constructed with the
therapy bag having at least one major face which comprises at least
25% of the total surface area of the therapy bag, and the movable
surface can be moved into contact with the at least one major
surface so that contact between the at least one major surface and
the movable surface covers at least 50% of the surface area of the
at least one major surface by the time that the movable surface is
fully extended. The therapy bag may comprise at least two fluid
flow ports within a fluid control element, one of the ports
comprising the exit port, and adjacent to at least one of the ports
is an element which has a storage area for a memory unit and access
ports to the memory unit. The memory unit may comprise, for
example, a chip (e.g., intelligence chip), and the access ports
enable electronic connection from an outside memory reading or
memory writing apparatus to the chip. The chip may be present
within the storage area, and the chip preferably contains
electronically readable information relating to at least two
different topics selected from the group consisting of the
prescription; the name of an active ingredient in the prescription;
the chemical name of a prescription carrier; additives in the
prescription; volume of the prescription; expiration date; name of
a prescribing doctor; name of a private loader; name of a local
supplier/manufacturer of ingredients of the prescription; source of
at least some materials in the prescription; a name of a therapy
bag manufacturer; a name of a pharmacist; a patient name; patient
information relating to at least one of age, allergies, address,
frequency of prescription refill, weight, chemical intolerances,
instructions for a flow control module with respect to desired flow
rates; intervals for delivery; rate and volume of delivery; and
drip rate.
[0014] The therapy infusion apparatus preferably provides the
movable surface as an extendable bladder which is expandable or
inflatable by a fluid (e.g., liquid or gas) to move a surface of
the bladder against a surface of the therapy bag.
[0015] A therapy bag for use in the infusion of liquids to a
patient is described comprising a flexible bag having a storage
area and a delivery end, the delivery end comprising at least two
fluid ports, at least one port capable of allowing fluid from
within said storage area when pressure is applied to liquid within
the storage area, and the delivery end also having a storage area
for storage of a memory element, the storage area having access
ports for electronically accessing the memory element. The storage
area preferably contains a memory storing element such as a chip
and there are electronic access ports oriented in the storage area
to allow external electronic access to the chip so that information
on the chip may be accessed. The storage area may be asymmetrically
located along the delivery end. At least two liquid flow ports may
be located to one side of the asymmetrically located storage area.
A battery may be located on the same side or the other side of the
ports as the storage area for the memory unit. The battery may
provide power to any electrical or electronic element on the pump
or apparatus, such as at least one electrically powered element on
the therapy bag selected from the group consisting of a display
panel on the pump, a chip, a fluid rate control element, and an
alarm (e.g., sound display, light display, vibration display, Radio
Frequency signal, electronic signal with a connection to computer
or communication system).
[0016] The infusion system of the invention is packaged in a
structured support system, such metallic, polymeric, or other
structural housing such as a light-weight nylon mesh container
which houses basic components of the infusion device. The
container, which is the system pump, may be provided with elements
to secure the container to a patient. These patient attachment
elements include belts, straps, harnesses, hooks, and associated
apparel (e.g., a shirt, jacket, girdle, side-pack, back pack or the
like having the container secured to a portion thereof or in a
pocket). A preferred support element comprises a loosely overlying
garment such as a harness, shoulder belt, waist belt, side-pack or
backpack, such as one constructed of fabric, such as nylon straps,
so the apparatus may be worn by an ambulatory patient. The
container alternatively may be suspended from a fixed support for
the patient immobilized in bed, in a chair or a vehicle.
[0017] A filled therapy bag containing the Rx to be infused into
the patient is associated with the pump, causing a fluid connection
element between the Rx and the pump as by insertion into the pump
by the medical practitioner, such as by a physician, attendant,
nurse or by the patient. With the therapy bag positioned in the
pump, a movable (force-providing) surface (such as an inflatable
bladder or moving wall element or moving plate located within the
walls of the container, as for example with the therapy bag placed
against an element) moves within the container walls to increase
pressure to the Rx within the therapy bag. The pressure against the
therapy bag may be provided by any element, especially any
non-puncturing element adjacent to or comprising an interior wall
of the pump which is in face-to-face (major surface or
side-to-side) contact with the Rx filled plastic therapy bag. Force
provided by against the inflated bladder provides the pressure
within or on the prescription bag which enables the flow of the
medication through the set.
[0018] An Electronic Control Unit (ECU), in the form of a
semiconductor microcomputer, and its battery power supply are
located within the structural housing, preferably within the pump's
assembly, as in a pocket, sleeve, housing, frame, pouch, lining or
container of the pump. The ECU plugs into an element which connects
memory or circuitry to the infusion system or within the set as
with electrical wires, cables, plugs, connectors or printed circuit
cable which electrically interconnects the various components of
the system. The ECU has the potential to perform the functions of
controlling the sequences of operation of the system and
components, monitoring the performance of the system and individual
components, and alerting the patient or a health supervisor of any
noteworthy condition or malfunction of the infusion system or any
part thereof. The ECU may include a ROM containing the
microcomputer's operating system, as well as operational programmed
routines which include displaying data relating to the system
status by means of visual display unit, such as an LED, LCD or
other visual display which may be mounted on the pump, visible to
the patient. The status data being stored in the ECU memory is also
available for visual display on a monitor (CRT, LED, LCD, etc.) or
later printout, even by means of a modem so that the information
may be transmitted to a medical control station distant form the
patient.
[0019] A fluid control module (FCM) may also be part of the set.
The FCM comprises an inlet port, an outlet port and a frame. Its
inlet port is to be connected to the therapy bag and its outlet
port supplying medication to the patient is connected to
intravenous tubing segment of the set by means of connectors such
as male-female connectors, slidable inserts, clamped tubes, or
hydraulic push-on connectors. Mounted in the FCM may be an
electronically connectable source of information such as a chip,
hardware, software source or semiconductor plug-in EPROM having
encoded within it information such as information concerning the
therapy medication, its dosage, rate of delivery, schedule of
delivery, and other information which may relate to the patient and
treatment. The software would be specifically designed for this
operation, allowing ready access to insertion of therapy specific,
patient specific, and pump specific information. Additional
specific information may be accessed such as required storage
conditions, actual storage conditions (e.g., a thermocouple could
be read to show conditions during transit), and the like may also
be addressed by the software. At the time of filling the
prescription, the pharmacist enters the information into the source
of information such as the EPROM chip by whatever information
insertion means are available, such as by replacing a chip, loading
a chip from or with his computer. The address bus of the ECU may be
interconnected with an EPROM via an electrical printed circuit
cable so that the ECU has access to the data and instructions
stored in the EPROM relating to the specific bag therapy. A data
storage element may be provided with a General Purpose Interface
Buss (GPIB) for receiving and selection of appropriate data from
the pharmacists required input. This information will be loaded
onto the chip resident in the fluid control module. The information
will usually be loaded at the tome that the therapy bag is being
filled.
[0020] With the therapy bag and attached FCM loaded into the pump
system, operation commences in one or two different manners. In one
format, operation may start only after a security routine within
the system (either hardware or software) checks to assure that a
therapy code on the therapy bag and/or FCM matches a code in the
pump. This assures that the therapy bag being loaded or inserted in
or onto the pump is the proper therapy. After clearance by the
security check, the operation may begin. An alarm or indicator may
be provided to indicate an improper connection or record of
misconduct in the use of the wrong therapy in the bag. These events
may also be recorded in the pump buffer. Another format would begin
operation when the "start" button is depressed or a timed signal
initiates the operation (e.g., from data in the EPROM). The coding
in the EPROM is read by the ECU and a signal is sent to the FCM
locking it up so that fluid cannot flow until such direction is
given or allowed. Elements are provided to expand the bladder to a
pressure level prescribed by pump logic so that contained 5 liquid
may be put under pressure. The pressing of the bladder may be by a
plate or surface coming into contact with the exterior of the
bladder, a collar moving along a surface of the bladder or any
element which attempts to compact the space within the bladder. For
example, a small air compressor under control of the ECU supplies
air to the bladder whose pressure is monitored by a pressure
transducer. The air compressor is cycled on and off by the
microcomputer to maintain bladder pressure in accordance with the
pressure value required by the Rx and encoded in the EPROM. A
start-up program enables the user to bleed air out of the system
when desired (even before fluid is actually pumped), and a message
may be provided on the display of the ECU would then advise the
user that the batteries are OK, and that the system may be
connected to the patient's body. With the intravenous connection
made, the patient may then push the start button, and the
programmed delivery is begun. Under control of the ECU, the FCM
meters the flow of the medication by cyclically dispensing precise
volumes of fluid through its outlet port. Each cycle of the FCM
generates a signal pulse which is detected (e.g., simply by a
counter, flow-meter, pulse meter, or other sensor meter) or by a
detector such as a Hall-effect sensor, a photodiode or the like and
the sequence of events or pulses is monitored by the ECU. Any
failure in flow would cause an interruption of the stream of pulses
from the Hall-effect sensor (or other sensor), and result in a
shutdown of the system (the interruptions were designated as
sufficiently extreme) and initiation of an alarm sequence by the
ECU as will be explained below. Also, when a system shutdown
occurs, a check valve in the set line to the patient's body may
actuate to preclude any back leakage from the patient's circulatory
system into the infusion system.
[0021] In the case of infusion of analgesics, a patient controlled
analgesic (PCA) button on the ECU cooperates with the logic control
loop to a) check with a buffer to see if patient controlled
administration of the analgesic is permitted; b) if PCA is
permitted, at what delivery rate or amount, the number of PCA's,
etc.; c) permit the patient to enhance or beef-up the paint control
or the rate of administration in accordance with the steps outlined
above, and provide a confirming signal (e.g., a sound signal); and
d) in some cases, no Rx may be delivered, but the sound signal can
be given as a placebo.
[0022] The elements of the infusion system may be assembled and
programmed to operate either open loop or closed loop.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a drawing of a packaged infusion system within the
scope of the invention,
[0024] FIG. 2 is a drawing of the infusion system of FIG. 1 in the
open position,
[0025] FIG. 3a is a drawing of the therapy bag of the invention and
associated interconnecting units,
[0026] FIG. 3b is a drawing showing the location of electronic
components of the invention,
[0027] FIG. 3c is a drawing of a first embodiment of a fluid
control module of the invention,
[0028] FIGS. 4a, 4b and 4c are drawings of additional views of the
fluid control module of FIG. 3c,
[0029] FIGS. 5a-5b are drawings showing the internal components of
the fluid control module of FIG. 3c,
[0030] FIGS. 6a-6d are schematic drawings illustrating successive
positions of the magnets located within the fluid control module of
FIG. 3c,
[0031] FIG. 7 is a graph of the partial contours of the rotors
within the fluid control module of FIG. 3c,
[0032] FIG. 8 is a block diagram of the infusion system of the
invention,
[0033] FIG. 9 is a drawing of a second embodiment of the therapy
bag of the invention,
[0034] FIG. 10 is a drawing of the therapy bag of FIG. 9 positioned
for insertion in the infusion system of the invention, and
[0035] FIGS. 11-14c are drawings of alternative embodiments of a
fluid control module in accordance with the invention.
[0036] FIG. 15 shows a schematic rendition of an idealized
association of a therapy bag and tubing with respect to the heart
of a patient (not shown).
[0037] FIGS. 16a, 16b and 16c show a perspective view of elements
of the system of the invention as used in a series of steps
engaging a fluid control module.
[0038] FIG. 17 shows a cut-away view of separate components which
may be used in an example of a fluid control valve assembly similar
to that shown in FIG. 16.
[0039] FIG. 18 shows a cut-away, side view of one of a number fluid
control valve assemblies useful in the practice of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0040] The use of prescription delivery bags or pouches for the
dispensing of fluid prescriptions or supplements should entail a
number of properties to be acceptable to the medical profession and
to the user. The delivery system must provide dependable delivery
of prescribed materials, the system should be capable of use with
minimal potential for error, the system should enable patients
rather than highly skilled medical personnel to connect and operate
the system, the system itself should operate to minimize errors in
the delivery of the correct prescription, and patients desire to
have delivery systems which are less conspicuous. The present
invention is able to address some of these concerns and provide a
dependable, easy to operate, inconspicuous prescription bag
delivery system.
[0041] There are four distinct areas of technology or components in
the practice of the present invention which operate together to
form the delivery system of the present invention. Each of these
components comprise inventions capable of independent as well as
system invention according to the present invention. Those areas
include 1) the pouch containing the liquid material to be delivered
by infusion (e.g., intravenously) to a patient, 2) a fluid control
mechanism (FCM) (which may be incorporated into or onto the pouch
containing the liquid to be delivered, 3) an electronic control
module (ECM), and 4) a housing for the pouch, FCM and ECM.
[0042] The invention includes a therapy infusion apparatus for
delivery of therapeutic fluid to a patient, the apparatus
comprising:
[0043] a flexible therapy bag,
[0044] b) a movable surface which can apply force to an outside
surface of the therapy bag to increase fluid pressure within the
therapy bag,
[0045] c) an exit port in the therapy bag which will allow fluid to
exit in a delivery direction from the flexible therapy bag under
pressure,
[0046] d) an adjustable, fluid control element located along the
deliver direction, after the exit port.
[0047] The therapy bag of the infusion apparatus may have at least
one major face with a movable surface which movable surface
comprises at least 25% of the total surface area of the therapy
bag, and the movable surface can be moved into contact with the at
least one major surface so that contact between the at least one
major surface and the movable surface covers at least 50% of the
surface area of the at least one major surface by the time that the
movable surface is fully extended. The movable surface preferably
comprises an extendable bladder. The bladder may be expandable or
inflatable by a fluid (preferably a liquid) to move a surface of
the bladder against a surface of the therapy bag. The therapy bag
may, for example, comprise at least two fluid flow ports within a
fluid control element, one of the ports comprising the exit port,
and adjacent to at least one of the ports is an element which has a
storage area for a memory unit and access ports for accessing
information from a memory unit within the storage area. The memory
unit preferably comprises a chip, and the access ports enable
electronic connection from an outside memory reading or memory
writing apparatus to the chip. The therapy infusion apparatus may
have a chip present within the storage area, and the chip would
contain electronically readable information relating to at least
two different topics of information selected from the group
consisting of a prescription for the therapeutic material; the name
of an active ingredient in the prescription; the chemical name of a
prescription carrier; additives in the prescription; volume of the
prescription; expiration date; name of a prescribing doctor; name
of a private loader; name of a local supplier/manufacturer of
ingredients of the prescription; source of at least some materials
in the prescription; a name of a therapy bag manufacturer; a name
of a pharmacist; a patient name; patient information relating to at
least one of age, allergies, address, frequency of prescription
refill, weight, chemical intolerances, instructions for a flow
control module with respect to desired flow rates; intervals for
delivery; rate and volume of delivery; and flow rate as a function
of time (the prescription program). The system of the invention may
have various elements, subelements, components and subcomponents
that are disposable after a single use or a few uses. The relative
low cost of the elements enables this disposability, just as the
need to avoid cross-contamination between patients and the need to
prevent storage contamination of components makes replacement
desirable.
[0048] The therapy bag for use in the infusion of liquids to a
patient may comprise a flexible bag having a storage area and a
delivery end, the delivery end comprising at least two fluid ports,
at least one port capable of allowing fluid from within the storage
area when pressure is applied to liquid within the storage area,
and the delivery end also having a storage area for storage of a
memory element, the storage area having access ports for
electronically accessing the memory element. The storage area may
be asymmetrically located along the delivery end. There may be at
least two liquid flow ports are located to one side of the
asymmetrically located storage area. The pump may have a battery
(preferably a replaceable battery) as an element therein. The
battery is used at least to provide power at least to the chip (and
any servomechanical or electromechanical or electrical elements
within the system). The battery may also provide power to at least
one electrically powered element on the pump or therapy bag
selected from the group consisting of a display panel, a chip, a
fluid rate control element, and sound alarms.
[0049] The therapy infusion apparatus may further comprise
[0050] e) a fluid flow detector that determines at least whether
therapeutic fluid is flowing through, towards or past the exit
port;
[0051] f) a meter measuring flow rates of the therapeutic liquid
within or out of the therapy infusion apparatus; and/or
[0052] g) an alarm that activates upon malfunctioning or
interruption of any defined function of the therapy infusion
apparatus during loading of a therapy bag or delivery of
therapeutic liquid to a patient or movement of therapeutic liquid
within the therapy infusion apparatus.
[0053] The therapy infusion apparatus may further comprise a
microcomputer for controlling at least one operating function of
the infusion apparatus.
[0054] The memory chip in the infusion therapy apparatus is
programmable by an auxiliary computer external to the infusion
apparatus, whereby information may be entered for storage in the
chip relating to the therapeutic fluid.
[0055] The therapy infusion apparatus may also have a pump present
within the apparatus which pump comprises:
[0056] a) flexible enclosure member wherein the elements comprising
the infusion apparatus are mounted,
[0057] b) a bladder located in the pump, wherein when the therapy
bag is positioned in the pump the surfaces of the therapy bag are
substantially in contact with the bladder,
[0058] c) air compressor for inflating the bladder,
[0059] d) pressure transducer for measuring the air pressure in the
bladder, and
[0060] e) a vent for controllably venting the bladder.
[0061] The apparatus may further comprise a meter measuring
quantities of therapeutic fluid and the meter comprises:
[0062] a) a shell having an interior cavity, the cavity having an
input port for accepting the medicinal fluid from the therapy bag
and an output port for transferring the medicinal fluid out to the
patient,
[0063] b) first and second axles parallelly mounted in the
cavity,
[0064] c) first and second longitudinally extending rotors,
[0065] d) first and second fixed bar magnets mounted with the axes
of the magnets directed along the longitudinal axis of the first
rotor, the first rotor having a first cycloidal contour,
[0066] e) third and fourth fixed bar magnets mounted with the axis
of the magnets directed along the longitudinal axis of the second
rotor, the second rotor having a second cycloidal contour, the
first and the second rotors rotatably mounted on the first and the
second axles, wherein the longitudinal axis of the first rotor is
perpendicular to the longitudinal axis of the second rotor, and a
portion of the first cycloidal contour is substantially in contact
with a portion of the second cycloidal contour,
[0067] g) the shell having an interior wall in the shape of a
continuous closed curved surface,
[0068] h) the first rotor having a portion of its contour in
contact with the wall, the second rotor having a portion of its
contour in contact with the wall, wherein a first chamber is formed
bounded by the first rotor the second rotor and the wall, and a
second chamber is formed bounded by the first rotor the second
rotor and the wall, the first chamber containing the inlet port and
the second chamber containing the outlet port,
[0069] i) a reciprocating shuttle proximate the shell, the shuttle
comprising movable fifth and sixth magnets, the fifth magnet for
interaction with the first and second magnets when the shuttle is
actuated to position the fifth magnet to attract the first or the
second magnet allowing rotation of the first and the second rotors,
and the sixth magnet for interaction with the third and the fourth
magnets when the shuttle is actuated to position the sixth magnet
to attract the third or the fourth magnet allowing rotation of the
first and the second rotors, whereby for each quarter rotation of
the first and the second rotors a fixed quantity of medicinal fluid
is forced from the second chamber through the outlet port, and j)
electromagnetic actuating means for alternately driving the shuttle
back and forth, the electromagnetic actuating means under control
of the microcomputer.
[0070] The outlet port may include a check valve opposing fluid
flow back into the cavity, and the meter may comprise a rate of
magnetic field change electrical transducer. The alarm system may
be activated by a microcomputer responsive to a fluid flowing
through the meter. The infusion apparatus may also comprise
either
[0071] h) a display driven by the microcomputer, the display
visually indicating any defined apparatus malfunction, or
[0072] b) an audio system driven by the microcomputer aurally
indicating any defined apparatus malfunction.
[0073] The therapy infusion apparatus may further comprise:
[0074] d) alarm information available from the microcomputer as
input to a modem for transmission over an external communication
line.
[0075] A method of infusing a medicinal fluid to a patient may
comprise the steps of:
[0076] a) filling a therapy bag with the medicinal fluid,
[0077] b) recording on a semiconductor EPROM the characteristics of
the fluid and the necessary information related to infusing a
patient with the fluid,
[0078] c) reading the information from the EPROM by a
microcomputer,
[0079] d) generating control signals in accordance with the
information by the microcomputer, and
[0080] e) activating a fluid dispensing unit in response to the
control signals, whereby the fluid dispensing unit infuses the
patient with the medicinal fluid through set tubing in accordance
with the recorded information.
[0081] A relatively standard therapy bag or pouch 24 for the
transportation of prescribed material to a patient for infusion is
shown in FIG. 3a. The therapy bag 24 is shown with three ports, a
fill port 32 (through which the pharmacist or other medical
personnel can fill the therapy bag), an access port 34 (from which
a liquid conductive lead or tube lead going to a patient is
connected), and an optional testing port 39 from which sample may
be drawn for preliminary testing, if desired. On the other hand,
FIG. 9 shows a therapy bag more consistent with the practice of the
present invention. The therapy bag 24' still has a fill port 32'
and an access port 34' leading to and from the storage area 33 of
the therapy bag 24', but a fluid control mechanism (FCM) 14' is
shown associated with both the fill port 32' and the access port
34'. The FCM 14' contains an accessible source of information such
as a chip 44' or microchip or other information storage element
within the FCM 14'. This accessible information is accessed by an
electrical or electronic connection to a device capable of reading
the information (e.g., computer, CPU, circuit board, etc.). A flow
control valve 124 or valve port 124 is also shown within the access
port 34'. It is to be noted that the center of the space between
the two ports 34' and 32' are not symmetrical to the edge 31 of the
therapy bag 24' to which they are connected. This is a desirable,
but optional, design feature that will be explained later. A tip
42' or connection to tubing is shown on access port 34'. The
structural features 27 and 29 are merely convenient representations
of one style of housing in the FCM 14'. The relatively square
features are matters of choice, not required function, although the
rear portions 37' of the flush receiving grooves 35' may be fitted
so that these elements nest easily together. A central segment 35'
of the FCM 14' houses the accessible source of information, here
shown as a chip 44'. Four pin access holes 37 (collectively) are
shown on the end 39 of the central portion 35 of the FCM 14'. The
pin holes 37 are engaged by pins (not shown) which electronically
or electrically connect the chip 44 to a device which can read
information from the chip 44'. In the practice of the present
invention, a small buffer memory or memory access unit (not shown
in this figure) may be in another part of the system electrically
connected to the chip 44' during operation of the system. The chip
44' may also be connected to a memory or device capable of reading
the information on the chip 44' such as a personal computer or
integrated home security system or telephone or cable connection
which may access a distant information reading system. For example,
a modem may be available on a telephone which can accept wires from
the pins 37 and transmit the information read from the chip 44' to
a central location, as well as connecting the pins 37 to a more
local source within the system or available for access by the
system.
[0082] As noted earlier, the spacing outside of the area covered by
the FCM 14' access port 24' and input port 32' may be unequally
distributed. As shown in FIG. 10, the areas 41' and 43' adjacent to
the flush receiving grooves 35' are not of equal dimensions. Here
it is shown (by way of example) that the panel area 41' is bigger
than panel area 43'. The purpose for this is to enable the
placement of additional components underneath the panels 41' and
43' with fewer restrictions in size. For example, a much larger
(and therefore more likely to be a more longer lived) energy source
may be placed under panel 41' than if panel 41' were the same size
as panel 43'. Similarly, as motors may be small without sacrificing
their ability to perform any necessary functions, they may be
located under panel 43' while preserving the larger space desirable
for the energy source and other elements which may be placed under
panel area 41'. The asymmetric location or formatting is also
intended to prevent the inadvertent placement of the bag into the
pump upside down. As shown in FIG. 10, a valve port 124 is shown
receiving a rotatable stopper 122 which can be driven by motor (not
shown) under panel area 43' and powered by a battery (not shown)
under panel area 41'. The motor may cause the rotatable stopper 122
to rotate to open or close the flow or passage of liquids within
the access port 34'. Upon appropriate signaling, as from the
information stored on the chip 44' delivered to the motor.
[0083] The chip 44' may be inserted into the central area 35 (or an
adjacent area with respect to either of the ports 32' and 34') and
be secured by natural tension or pressure against the sides of the
chip 44'. Any other normal securement means, such as placing
grooves on the side(s) of the chip which slide along raised areas
or snap into projections, clips, a flange may open to receive the
chip and then snap into place to lock in the chip 44', posts which
slide through the shell of the central area 35 into holes in the
chip, and the like may also be used. It is preferred that upon
assembly of the unit and system and placement for use by (e.g., on)
a patient, that the pin access holes 37 face in a downward
direction (meaning that the access port 34' also faces downwardly.
This allows gravity to assist the flow of liquid within the storage
area 33 of the therapy bag 24' and to remove any air or other gases
which may be present within the storage area 33 from the access
port 43'. It is also possible to use the flow of liquid through the
valve port 124 to control opening of the valve port in part by
gravity although usually a tensive or tension producing element
(e.g., spring, magnet, elastic element, etc.) may be used to keep
the valve port 124 closed while fluid pressure from a pump (not
shown) forces the valve mechanism open. An example of a system with
a magnet (to provide attractive force in a desired direction) and
cork (to provide buoyancy forces) as such closure mechanisms for
valve ports is shown in FIGS. 14a, b and c. As noted, such forces
may readily be substituted by springs, electromagnetic forces,
electrostatic forces, elastic elements, and the like.
[0084] The chip inserted into the FCM may contain whatever
information may be important or thought to be important by the
pharmacist, doctor and/or patient. The nature and content of the
information placed onto the chip is also indicative of aspects of
the present invention. For example, before insertion into the FMC
(or after insertion, before, during or after loading of the therapy
bag), information such as 1) the prescription, including the active
ingredient (e.g., drug), carrier, additives, volume, expiration
date, doctor, private loader (distal pharmacist), local
supplier/manufacturer, laboratory source of materials, therapy bag
manufacturer, pharmacist, patient name, patient information (e.g.,
age, allergies, address, frequency of prescription refill, weight,
chemical intolerances, and other information which may even be
automatically downloaded from a background source of patient
information), instructions for a flow control module (e.g.,
dependent upon the model and/or manufacturer, and even age of the
unit) with respect to desired flow rates, intervals for delivery,
rate and volume of delivery, drip rate, and the like.
[0085] FIG. 10 also shows features of particular embodiments of an
FCM which may be used in the practice of the present invention. For
example, the FCM 14' is shown already inserted into the therapy bag
24' at the time that the therapy bag 24' and the FCM 14' are placed
into the housing 12' and nestled within the flush receiving grooves
35'. In this way, the therapy bag 24' has been provided with the
information in the chip 44' from the point of delivery of the
therapy bag 24' as opposed to attempting to separately supply the
chips. The FCM and the bag from different sources. It is possible
that the chip, FCM and bag may be shipped together and connected at
the point of use (at home, office, hospice, residence of care, or
hospital), but this merely adds to the complexity of use, rather
than reducing that complexity.
[0086] It is well known within the medical and pharmaceutical
industry that mislabeling, misadministration, misdosage, and/or
misuse of pharmaceuticals, including those delivered in therapy
bags, has led to injury or death in patients. This system can
significantly reduce even the possibility of such problems. In
addition to carefully identifying the materials, sources, patients,
dosage, and rates for use of the prescription, that information can
be used upon reading of the information on the chip to assure that
the particular delivery device (which may also include patient
identification information and the like) is the proper device
through which the prescription is to be delivered. For example, the
chip in the FCM may identify the specific administration device (by
unit number, model number, location, patient identifier and the
like), and that information is compared on site with the
information provided by the delivery device. If there is no match
between the information, such as where the bag has been
misdelivered or the wrong chip inserted, an alarm or other
notification to the potential user would indicate an error. The
degree of the error would determine whether or not the programmed
delivery would occur.
[0087] Referring to FIG. 1, an assembled infusion system 10
includes a pump unit 12, the fluid control module (FCM) 14 docked
in a pocket of the pump 12, a partial view of the set 16, shoulder
straps 18 for supporting the pump 12, a display 20 part of an
electronic control unit (ECU) 22. FIG. 2 shows the interior of the
pump unit 12, and FIGS. 2, 3a, 3b display the components of the
infusion system 10 in greater detail. A therapy bag 24, (FIG. 3a)
shown prior to being loaded into the pump 12, is configured to fit
into the pump 12 in contact with a bladder 26 which is anchored to
the flap 28 of the pump 12 as well as to the body 30 of the pump
12. When installed in the pump 12, the therapy bag 24 lays between
the folded halves of the bladder 26. The bladder 26 is removable
from the pump 12 and may be periodically replaced.
[0088] The therapy bag 24 is fabricated from a flexible material
such as plastic, fabric, or composite materials and contains an
input connector 32 used by the pharmacist in filling the bag 24,
and an output connector 34 connecting to the set tubing 16. In
series with the set tubing 16 is the FCM is 14 inlet port 38 and
outlet port 40 connected to a section of set 16 tubing 42 which
feeds the medication to the patient. Referring to FIG. 3c, the body
of the FCM 14 includes a an external electrical connector 44 and an
internal socket 43 wired to the connector 44. The plug-in element
(here shown in a non-limiting manner to be an EPROM 46) mates with
the socket 43. When the pharmacist fills the therapy bag 24 in
accordance with the doctor's prescription, he also programs the
EPROM 46 by means of his information storage or writing device such
as a computer and an associated EPROM writer to contain the
essential information related to the prescription. This may include
the patient's name, the doctor's name, the name and supplier of the
medication, rate of flow and the flow profile as a function of time
for dispensing the medication, checking the medication viscosity,
and a telephone dial-up program to obtain help if the infusion
system 10 malfunctions. In the assembled infusion system 10, the
FCM 14 docks into the recess 36 located in the body 30 of pump 12
(FIG. 2). The recess 36 contains a connector which mates with the
FCM connector 44, and which feeds a flex printed circuit cable 56
running up to an electronic module 48. The electronic module 48
contains the ECU 22, an LCD display 20, a miniature air compressor
50, a "start" button 52 and a "stop" button 54. The electronic
control module 48 is enclosed in the top area 58 of the pump 12 as
shown in FIGS. 1, 2 and 3b.
[0089] Referring to FIG. 4a, the FCM 14, is a preferably
non-magnetic enclosure preferably fabricated from a plastic,
composite, or metal in the form of a cavity having top and bottom
planar surfaces and shell like side wall. The FCM 14 has an inlet
port 38 and outlet port 40, and has two interlocking internal
rotors 60, 62 which control the flow of the therapeutic or diet
supplemental medicinal fluid. The rotors 60, 62 are identical in
shape, having in general hourglass-shaped contours, and their
operation and geometrical outlines will be more fully described
below. The FCM also has a check valve 64 installed in the outlet
port 40. Referring to FIG. 4b fixed magnets 66, 70 are mounted on a
control linkage 72 positioned below the FCM's 14 body containing
the rotors 60, 62. The control linkage 72 is shuttled
bi-directionally, as shown by the arrows 77, by the operation of a
motor 74 rotating an offset cam 76. The shuttling motion of the
control linkage 72 alternately positions one of the magnets 66, 70
adjacent to one of the rotors 60, 62. For each extreme position of
the shuttling linkage 72, only one of the magnets 66, 70 is within
range to magnetically influence one of the rotors 60, 62.
[0090] Referring to FIG. 5a, the rotors 60, 62 which are molded
plastic parts, are shown mounted on rotational axes 78, 80
respectively, positioned within the cavity of the FCM 14. The rotor
60 has magnets 84, 86 and the rotor 62 has magnets 90, 92
longitudinally embedded along the long axes of the rotors 60, 62.
The north poles of the magnets 84, 86, 90, 92 are oriented facing
the longitudinal ends of the rotors 60, 62. Mounted coaxially about
the axes 78, 80 and rigidly connected to the rotors 60, 62 are
interlocking spur gears 94, 96, ensuring that both rotors rotate
simultaneously, and in counter rotating directions.
[0091] In FIG. 5a, for the rotor positions depicted, the south pole
of the control linkage magnet 70, is oriented so that it is in
close proximity to the north pole of the magnet 90 embedded in the
rotor 62, while the control linkage magnet 66 is horizontally
displaced away from the magnetic structures of the FCM 14. The
south pole of magnet 70 is strongly attracted to the north pole of
the magnet 90, locking the position of the rotor 62 ( and
simultaneously locking the rotor 60 due to the intermeshing spur
gears 94, 96), keeping both of the rotors 60, 62 immobile. With the
inlet port 38 of the FCM 14 connected to a fluid filled therapy bag
24 which is under pressure from the bladder 26, for the locked FCM
14 condition described above no fluid, other than a small
controlled "non clotting flow" traversing a small intentional gap
94 between the "in contact" contours of the rotors 60, 62, can flow
through the FCM 141.
[0092] In open loop operation of the infusion system 10, (FIG. 8),
the actual fluid flow to the patient is effected and controlled in
the following manner. The electronic control unit 22 executes its
internally stored operating system program and the delivery related
programmed information stored in the EPROM 46 by the pharmacist,
initiating a (for example, time-related parallel) sequence which
activates the fluid (e.g., air) compressor (or pump) 50. As the air
(fluid) compressor 50 inflates the bladder 26, a pressure
transducer 27 internal to the bladder 26 measures the bladder
pressure and transmits it to the ECU 22. Stored within the EPROM 46
is the appropriate bladder 26 pressure for dispensing the
prescribed medicine from the therapy bag 24 at the correct flow
rate, and the cycling rate at which the FCM 14 must operate to
effect the proper flow. This portion of the ECU 22 program sends
"turn on" pulses to the motor 74 Each pulsation of the motor 74
shuttles the linkage 72 back or forth (77) oscillating the
positions of the magnets 66, 70 ( FIGS. 5a and 5b) relative to the
body of the FCM 14 so that either rotor magnet 84 or rotor magnet
86 is attracted to magnet 66 or magnet 70.
[0093] Referring now to FIG. 6a-6d, the position of the rotors 60,
62 their associated magnets 84, 86, 90, 92, and the control linkage
magnets 66, 70 are schematically represented for controlling flow
through the FCM 14. FIG. 6a shows the positions of the rotors and
magnets corresponding to the rotor configuration of FIG. 5a. The
magnet 66 strongly attracts and holds the magnet 84 stationary,
locking the rotor 60 against rotation, and correspondingly locking
the rotor 62 coupled by the spur gears 94, 96 to the rotor 60. It
is to be noted that the fluid from the therapy bag 24 under
pressure from the bladder 26 has filled the inlet cavity 100 (FIG.
5a) of the FCM 14. However, flow of the fluid from the inlet cavity
100 is blocked by the stationary rotors 60, 62. Hence, there is no
flow of fluid that is contained within the outlet cavity 102 (FIG.
55) of the FCM 14 to the patient through the outlet port 40. For a
bolus of medication to flow from the FCM 14, the program of the ECU
22 transmits a "rotate command" to the motor 74 (FIGS. 4b and 4c)
and the motor 74 rotation shuttles the command linkage 72 to shift
the magnet 66 from its position proximate the rotor magnet 84. This
frees the rotor 60 from the magnetic force of the magnet 66 and
allows it to rotate (e.g., in a cogging or geared or screwed
manner) a quarter turn, while the rotor 62 rotates in the opposite
direction. Because of the geometrical configuration of the contours
of the rotors 60, 62, the fluid pressure within the inlet cavity
102 applies a greater force perpendicular to the moment arm of the
rotor which is in contact with the waist of the other rotor, than
the fluid pressure applies to the moment arm of the rotor in
contact with the shell 82 of the FCM 14. (The moment arm of rotor
60 in contact with the waist of rotor 62, compared to the moment
arm of the rotor 60 in contact with the cavity shell 82, in this
example). This difference in force causes the "just released" rotor
(rotor 60 in this example), to rotate in a counterclockwise
direction, while the rotor 62 rotates in a clockwise direction. In
the meantime, the magnet 70 has been positioned by the linkage 72
into the position shown schematically in FIG. 6b, and after a
quarter rotation the magnets 84, 86 of rotor 60 and the magnets 92,
90 are positioned as shown, with the magnet 70 attracting and
holding the magnet 90. This quarter rotation has forced a bolus of
medication previously in the cavity 102 through the outlet port 40
out into the set connected to the patient. FIGS. 6c, 6d illustrate
sequences of further quarter turns of the rotors 60, 62 each of
which provides one bolus of medication to the patient.
[0094] The inner contour of the shell 82 (FIG. 5a) consists of two
semi-circular end surfaces connected by straight planar segments,
and the end faces of the rotors 60, 62 are in intimate contact with
the shell contour (82) blocking the passage of fluid at these
contact points. The shapes of the rotors 60, 62 are symmetrically
cycloidal, and their contours are partial epicycloidal and
hypocycloidal curves. Referring to FIG. 7, the contour of the first
quadrant of the rotors 60, 62 is shown divided into 2 zones, 106,
108. The angle .phi. is the angle between the X axis and the curve
defining the first quadrant of the rotor 60, 62. In the zone 106
where .phi.=,.pi./4 to .pi./2, and defining the rolling radius that
generates the epicycloidal contour as A, the coordinates of the
contour XI, Y1 are generated by the equations:
X1=5A[cos.phi.]+A[cos5.phi.]YI=5A[sin.phi.]+A[sin5.phi.] In zone
108 where .phi.=.pi./4 to 0,
[0095] with the same rolling radius A, the coordinates X2, Y2 are
given by the equations:
X2=3A[cos.phi.]-A[cos3.phi.] Y2=3A[sin.phi.]+A[sin3.phi.]
[0096] These equations, when solved for various values of A, yield
the first quadrant boundary coordinates as a function of .phi..
From this, one can derive the symmetric complements of the first
quadrant to develop the total outside contour of the rotors 60, 62.
The above equations are provided as an example of generating the
rotor contour; other cycloidal expressions may yield equally valid
contours. With the contours determined, the volume of an outlet
cavity, i.e. 102, may be determined, and by way of example, in a
FCM having rotors 60, 62, 1/8 inch in height, and for a rolling
radius A=0.030 inch, the FCM will deliver 0.1851 ml/rev. This
provides the flow control constant to the ECU 22 memory allowing
the software to establish the volumetric flow per quarter
revolution.
[0097] The rate of flow of medication is thereby determined by the
program of the ECU 22 which controls the command rate to the motor
74. Referring again to FIGS. 4c and 8, a Hall effect sensor 104 is
positioned in the pump 12 adjacent to the recess 36 in which the
FCM 14 is docked. A pulsed electrical output of the Hall effect
sensor 104 occurs for each quarter rotation of the FCM rotors 60,
62 due to the changing magnetic fields at the sensor 104. This
electrical pulse is monitored by the ECU 22 to confirm that the
rotors 60, 62 are actually rotating at the rate set by the ECU 22.
It will be noted that if the FCM 14 rotors fail to rotate due to a
blockage or due to a failure of the bladder 26 or therapy bag 24 to
provide fluid at the pressure necessary to generate the torque
required to rotate the rotors 60, 62, no output from the Hall
sensor 104 is detected and the ECU 22 activates an alarm. This
alarm generates a flashing message on the display 20, as well as an
audible alarm from a small speaker mounted in the pump 12. It also
deflates the bladder 26 and immobilizes the air compressor 50.
Also, if the patient 11 attempts to remove the therapy bag 24 in an
unauthorized manner, the ECU 22 activates a relief valve 116 which
deflates the bladder 26 and the ECU 22 initiates an alarm
subprogram. A further feature of the alarm system which comes into
play when the patient 11 is in bed utilizes a modem included in the
ECU 22 which is connected to a wall mounted plug-in telephone line.
The activation of the alarm causes the ECU 22 to dial up a stored
fax or telephone number and to transmit information via the modem
from the ECU 22 storage describing the status of the infusion
system 10, and summoning help if required.
[0098] In a second embodiment, the infusion system of the invention
operates closed loop. In this configuration the interconnection
between the system elements are substantially the same as shown in
FIG. 8, except that the output of the Hall sensor 104 fed back to
the ECU 22 is not used simply as a detector of the rotation of the
rotors 60,62, but the rotation rate is compared to stored flow
:rate values in the ECU 22 memory to develop an error signal
proportional to the deviation of the flow from the required flow
rate. Depending upon the magnitude and sign of this error, the ECU
either increases the pressure in the bladder 26, or decreases it by
controlling the speed of the air compressor 50, thereby servoing
the flow rate to the desired value.
[0099] A third embodiment, illustrated in FIGS.9-13, discloses the
FCM 141 as an integral part of the therapy bag, 241. (in the
drawings, different but related elements are identified by the same
reference character, albeit that the different elements are
distinguished by primes) in the earlier embodiment of FIG. 3c, the
FCM 14 is not integral with the therapy bag 24, but is a separate
unit connected to the therapy bag 24 by the set tubing 16. In the
third embodiment, the FCM 141 is included in the output connector
341 of the therapy bag 241 ( FIGS. 9, 10) and the tubing 421 to the
patient connects to the output connector 341 containing the FCM
141. The therapy bag 241 is filled by means of the input connector
321 and contains an electrical connector 441 connecting with an
EPROM (not shown) internal to the therapy bag 241 which performs
the same function as the EPROM 46 as previously described above.
Associated with the input connector 321 and output connector 341 is
a docking element 35 which fits into a mating recess 37 (along with
the input and output connectors 321, 341), in the pump 121 when the
therapy bag 241 is assembled with the pump 121.
[0100] The FCM 141 may be seen by referring to FIGS. 11, 12, 13.
Part of the FCM 141 is the docking element 35, which is any
substantive material, such as polymer, composite or in this case a
fiberglass boxlike structure supporting a shaft 118 having bevel
gear 120 mounted on one end of the shaft 118, and a magnet 122
mounted on the other end of the shaft 118. The end of the shaft 118
on which the magnet 122 is mounted, fits into a cylindrical cavity
124 in the side of the output connector 341, however fluid from the
therapy bag 241 will flow around the outer walls of the cavity 124.
Mounted proximate the cavity 124 in the output connector 341 are
the other elements of the FCM 141, i.e. a "cork" 126 having one end
rounded, bulbous or spherically shaped and the other end in the
shape of a cylindrical rod, and an associated magnet 128 fitted
into the bulbous end of the cork 126. Referring to FIG. 10, the
docking element 35, when docked to the mating recess 37, causes the
bevel gear 120 to engage a spur gear 130 (FIG. 13) attached to
shaft of a drive motor 132. In FIG. 13 the small bar magnet 122 is
seen mounted on the opposite end the shaft 118 from bevel gear 120
, and when the docking element 35 is engaged in the recess 37, the
bar magnet 122 is facially juxtaposed opposite the magnet 128
attached to the cork 126. For the rotation position of the bevel
gear 120 shown in FIG. 13, the magnets 122, 128 are seen in
attractive positions of N versus S respectively, drawing the cork
126 to block the upper portion of the channel of the output
connector 341 (FIG. 14a), thereby operating as check valve denying
back flow from the set to the therapy bag 24. The motor 132
operates under control of the ECU 22, which controls flow of the
fluid by sending a rotate signal to the motor 132. Upon receipt of
a rotate signal, the shaft of the motor 132 rotates 180 degrees,
and the spur gear 130 drives the bevel gear 120 through 180
degrees, reversing the orientation of the magnet 122. This cause
the magnet 122 to repel the magnet 128 of the cork 126, moving the
cork 126 downward (as seen in FIG. 14a) from the check valve
position, and allowing the flow of the fluid from the therapy bag
241 around the cork 126 as shown by the dotted lines of FIG. 14b.
Under the pressure of the fluid flow the cork 126 moves down in the
channel of the output connector 341 until the bulbous portion of
the cork 126 snugly mates with the constriction in the channel of
the output connector 341 as shown in FIG. 14c. This shuts off the
flow from the pump 121, having allowed one bolus of fluid to flow
out to the patient. For the next rotation of the bevel gear 120
under control of the motor 132, the magnets 122,128 again attract
each other, returning the cork 126 again into the check valve
position of FIG. 14a.
[0101] Referring again to FIG. 13, an LED 134 directs a beam of
light through transparent walls of the output connector 341 to a
photodiode 136. The excitation for the laser led 134, and the
output of the photodiode are connected through the electrical
connector 441 to the ECU 22. Each time a bolus of medication is
transferred out through the output connector 341, the end off the
cork 126 interrupts the laser beam and a signal is transmitted to
the ECU 22 from photodiode 136. If the ECU signals for a cycle of
bolus, and there is no corresponding interrupted light output
sensed by photodiode 136 the alarm mode is activated by the ECU
22.
[0102] FIG. 15 shows a schematic rendition of an idealized
association of a therapy bag 200 and tubing 202 with respect to the
heart 204 of a patient (not shown). The FIG. 15 may be explained in
principle according to the following information.
[0103] 1. A bladder 206 exerts a measured pressure (Pi) on a
therapy bag 200.
[0104] 2. A pressure head h, results which is proportional to
h.sub.1-h.sub.2 (the differential between the upstream pressure in
the therapy bag 200 and the downstream head plus heart 204 created
fluid pressure (P.sub.j).
[0105] 3. Pi is the fluid pressure within the bag and
(h.sub.1-h.sub.2) is the operating pressure head. It is this
differential in pressures (P.sub.i-P.sub.j) which causes the fluid
in the bag to flow into or through the infusion system.
[0106] 4. A check-valve 208 (V.sub.1) with an effective area
A.sub.1 and a return spring 210 (with a flow resisting tension of
K.sub.1) impedes flow in conjunction with a check-valve 212
(V.sub.2) in the effective area A.sub.2 along with a return spring
214 (with a flow resisting tension of K.sub.2). Customarily, but
not absolutely, A.sub.1>A.sub.2 and K.sub.1<K.sub.2. This
relationship is important in sizing these components to prevent
unwanted flow such as might occur if one were to over pressure Pi
by squeezing, or sitting on the bladder.
[0107] 5. In the operating sequence V.sub.1 will permit the flow to
commence when the bladder 206 reaches the proper pressure (for the
given therapy program and viscosity .mu.). Fluid will pass thru
V.sub.1 but V.sub.2 will not permit flow since the opening
(cracking) force is designed not to permit flow at this instance.
An elastic or elastomeric (e.g., latex, rubber or silicone) tube
section 216 is designed to expand (e.g., up to a restraining
elements, such as a restraining chamber wall or partition element)
as a result of the higher upstream pressure Pi. When the tube
section 216 is in equilibrium with the upstream head. Still no flow
can occur thru V.sub.2. At this point, depending on the programmed
delivery rate, a slight pause in flow may occur.
[0108] 6. Since the flow source is stopped for an exact time to
control the rate of flow, all systems are idle. This may be for
only a part of a second up to several minutes or whatever is the
format and detail of a prescription requirement.
[0109] 7. When flow is again required, a "mouse trap" mechanism 218
will squeeze the tube 216 in an exactly desired angle of
deflection. This applied angle and the resulting reduction in tube
216 diameter reduces the tube's 216 volumetric capacity and the
fluid will attempt to flow in both directions. The upstream check
valve 208 prevents back flow; while the downstream valve 220 under
the momentary or transient force of the "mouse trap" opens the
downstream valve 220 and permits a given bolus of therapy to flow
until down stream equilibrium is attained, at which time, it will
also close, preventing back flow of the liquid. The mousetrap
mechanism 218 returns to the "set" or open position and the
elasticity of the tube and the upstream pressure fills the tube
where no reduction in tube 216 diameter is effected, again
completing the cycle.
[0110] 8. Since the bladder pressure is created by pumping a
relatively large volumetric area (of fluid, e.g., air or liquid),
compared to the bolus volume per cycle, the pressure can remain
almost constant for many boli of therapy pumped. The hysteresis
loop for pressure level control can be extremely small (for
example, from 0.5% or 1% to over to 1% or to 3% or less under
design requirements).
[0111] 9. The cycle is now completed, and the ECU will, through
suitable software and automatic programming, continue the infusion
program.
[0112] 10. The accuracy of flow delivery rate in the pump depends
on the control of several variables and dependable components. All
such equipment is constrained to these limits. The present
invention has designed a system that essentially has been reduced
to its simplest form.
[0113] 11. If a problem does occur, such as a crimp on tube or
other condition of occlusion, diagnostic sensors detect the problem
and inform the user. For example, if an occlusion occurs, the mouse
trap mechanism 218 will not go through its complete travel and the
current flow through the DC driver will rise and be easily detected
and reported. If the condition occurs on, for example, 5
consecutive cycles, an alert or warning signal is provided by the
system. Timers, pressures related sensors and positional detectors
each have a part in making sure that the pump of the present
invention is doing the best possible job of providing drug therapy
of any system in the market place at the lowest cost.
[0114] The pressure of the bladder forces therapy out of the set
bag, through the fluid control module (FCM) and via tubing into the
patient's artery (or other designated target delivery area). The
control of the rate of flow to the patient is a function of the
bladder pressure, the diameters of the tubes, the therapy
viscosity, the system losses (friction) and the control apparatus.
The apparatus may operate as described above for mechanics, and as
amplified below with respect to personal activity.
[0115] A. Therapy flows out of the therapy bag or set bag 200 into
the exit port (not shown) of the FCM (not shown in this Figure) and
is impeded by the first valve 208, but the pressure in the bladder
is high enough to override the cracking force required by the valve
208.
[0116] B. A second valve 220 could be opened by the flow, but the
forces to open the second valve 220 (resulting from a stronger
spring, smaller elastic element, smaller force providing mechanism
or a smaller seal diameter or one or more) are much, much greater
than the bladder pressure can exert and so the flow is stalled.
[0117] C. The upstream pressure is sufficient to enlarge the volume
of the tube 216 to a level that is equal to that pressure residing
in the bladder 206 and controlled by the ECM (not shown), and the
pressure sensor (not shown) in line.
[0118] D. When this equilibrium condition is attained the mousetrap
mechanism 218 squeezes the control-tube 216 slightly, the measured
volume is controlled by the plastic case (not shown) that forms the
outer housing of the FCM (not shown). The squeezing action reduces
the volume of the control-tube 216 and the fluid tries to escape
the confines of the tube 216 through the two valves 208 220. The
fluid cannot go upstream since the valve 208 is a full-check valve
in this direction.
[0119] E. The second valve 220 must open now since the force of the
mousetrap mechanism 218 is sufficient to open the second valve
220.
[0120] F. The control-tube 216 now contracts to its normal
condition permitting a known bolus of therapy to move down the tube
216 toward the user.
[0121] G. The size of the bolus and the rate of the cycle have been
computed by the ECU (not shown) in accord with the therapy used and
the programmed rate required by the Prescription.
[0122] H. The cyclic repetition rate, and the interim pauses, of
the above steps determine the average flow rate of the system. The
rate is capable of covering large variations of fluid delivery
requirements with highly accurate results.
[0123] I. The pump program can be altered by the patient, if
permitted by the program, so that he/she can enable a larger or
smaller flow rate to improve or minimize pain that sometimes might
occur, which is typical in a narcotic administration system within
modem hospital facilities. This is referred to as Patient
Controlled Analgesia, (PCA). In addition, a standard leak is
programmed into the delivery because very small bolus is required
to be delivered through the tube 216, at well known rates, to
prevent clotting at the tube connections.
[0124] If any malfunction, such as a kinked tube, e.g., should
occur, the expandable chamber (e) will not contract in the expected
time and an alarm will sound and a diagnostic displayed. This kind
of anomaly data is stored in the pump memory for later automatic
down loading. It is suggested that this download be a part of the
normal infusion sequence to serve as historical evidence.
[0125] The alternate FCM system described above will also pass the
basic design criteria demanded by the system design parameters that
were delineated at the start of this disclosure. These systems have
been modeled and their operation tested.
[0126] FIGS. 16a, 16b and 16c show assembly mechanisms for various
elements of the invention. FIG. 16a shows a fluid control module
300 with stub tubes 302 and 304 positioned for insertion into
openings 306 and 308 in the FCM assembly 300. The stub tubes 302
and 304 and 324 and 322 are likewise connected to openings 308 and
306 in some manner of physical connection, as may be, for example
only, by snap fit, fusion, or adhesive securement into position,
but are preferably adhesively secured, as with a radiation
sensitive or thermally sensitive adhesive. In FIG. 16b, a flexible
bag 320 is shown radio frequency (R.F.) welded to the two ports 322
and 324 to the fluid control module 300. Note the eccentricity of
the two ports 322 and 324 with respect to a symmetry line 326 in
the bag 320 to insure that the bag 320 is positioned properly
within the pump 364. FIG. 16c shows a flexible bag with attached
fluid control module 340 with the chip 342 being accessed by an
electronic information reading system 344 accessing the chip 342
through electrical connections or ports (not shown).
[0127] FIGS. 17a, 17b and 17c show a perspective view of the
elements of the system of the invention as used in a series of
steps engaging a fluid control module 300. A patient drops
(inserts) the flexible bag 360 with the fluid control module 300
affixed thereto into the pump 364. The bag 360 and the FCM 300 are
locked into the pump 364 so that additional operations may be
automatically performed. Information in the chip 342 (in FIG. 16a)
is downloaded into the pump 364 which has its own memory/read
system 366. FIG. 17c shows two hook elements 403 that cooperate
with a bale 450 to latch the fluid control module to the dock 366.
The act of latching may accomplish at least two objectives: 1) The
latching may complete or activate a connection to turn on a visual
signal (such as an LED, e.g., a green LED) to indicate that the
fluid control module in the correct position and the unit is
actively "on" for dispensing the treatment. 2) The latching may
also operate to permit the bladder to hold air an still operate.
When the bale 450 is removed, it opens the valve, letting the
bladder release any entrapped air so that the bag can be withdrawn.
FIG. 17c shows a locking mechanism for the engagement of a tube
(not shown in this Figure) with the receptor system 400 of the pump
(not shown in this Figure). One method of operation for this aspect
of the system would be the use of a precision cam that rotates one
turn per stroke. This would act like a modified "Scotch" yoke. Each
stroke would depress the volume of the exit tube. When the slider
retreats from the tube, the bladder would force the fluid to fill
the vacant volume. This is a very accurate procedure. A slide 404
engages a guide pin 412 to control its displacement path. The slide
404, upon reaching the end of its travel, actuates a sensor that
logically informs the controller of its position. That position is
then compared against a clock to manage the fluid flow rate. If the
rate varies from a normal flow rate or a programmed comparison rate
or programmed directed flow rate, as would be the case where a tube
was kinked, the slide 404 would be arrested for security reasons.
The slide is shown in this example to be driven by bevel gear set
416, and powered by a miniature DC motor with a gear train 420.
FIG. 17c shows a tube 306 squeezed by the slide 404. The slide 404
engages the tube 306, squeezing the tube 306 at a precise pressure
and at a precise rate and displacement.
[0128] FIG. 18 shows a cut-away view of separate components which
may be used in an example of a fluid control valve assembly similar
to that shown in FIG. 17. The connecting system 500 between a tube
322 from the therapy bag (not shown) to the tube 306 in the fluid
control module 300 and the tube 302 for (for example) intravenous
delivery of therapeutic liquid (not shown) to a patient (not shown)
is secured in a docking support 366 having other desirable
components therein. A check valve 512 is shown nesting against and
sealing with an abutting lip of the valve spacer 514 on the
interior of the docking support 366 towards the proximal end 516 of
the fluid control module 300. Towards the distal end 518 of the
fluid control module there is a control valve 520 whose operation
is elsewhere more particularly described. The control valve 520
engages an exit tube 302 for delivery of the therapeutic liquid.
After and during engagement of the therapy bag with the fluid
control module in the pump, data within a memory chip (not shown in
this Figure) is engaged and read. The programmed data insures the
safety of the patient with respect to operation and delivery of the
therapy in the bag. If the wrong bag or wrong prescription is put
in the pump, the pump shuts down at least delivery functions. The
data read from the chip sets up delivery and pumping parameters,
and may even direct changes to be performed in the sequence of time
or events in the delivery process (e.g., changing flow rates after
an initial rate of delivery, changing delivery rates over the
course of time of the day, etc.).
[0129] An upstream pressure (e.g., from the pump) drives the
therapeutic fluid through the check valve 512 and into the chamber
530 connecting the control valve 520 and the exit tube 302. The
chamber 530 is preferably a known, fixed volumetric quantity. The
FCM tube, preferably being an elastomeric material, will expand to
fill the chamber because of the memory (elastic memory) of the tube
and fluidic pressure. An actuator 404 will squeeze the tube 306
while the check valve 512 prevents fluid flow toward the bag (not
shown). A control valve 520 (in any type of known construction)
operates to prevent flow to the user unless there is pressure in
the chamber sufficient to activate or overcome the control valve
520. The pressure must reach a predetermined level, much greater
than that provided by the bladder in the pump. The actuator
accomplishes that increase in pressure on the fluid within the
chamber 530. Even simple constructions of control valves have
proven to be very accurate, even with relatively low flow
rates.
[0130] The pump is quiet, operates (for example only) on 4.7 volt
DC current (low voltage is below 10 volts). The pump should be able
to operate without bladder pressure as long as the fluid flow into
the chamber is not interrupted (e.g., the priming amount of fluid
is not achieved or is lost). The use of the actuator will also
facilitate the use of patient controls on the flow of therapeutic
(including pain control or analgesic materials) materials to the
patient. The data can therefore control a standard flow amount of
fluid to the patient, but the patient can modify the rate of
delivery up to a maximum level, controlled by the Rx data.
* * * * *