U.S. patent application number 12/238875 was filed with the patent office on 2009-02-12 for closed loop medicament pump.
This patent application is currently assigned to MEDTRONIC MINIMED, INC.. Invention is credited to David L. Thompson.
Application Number | 20090043291 12/238875 |
Document ID | / |
Family ID | 23168419 |
Filed Date | 2009-02-12 |
United States Patent
Application |
20090043291 |
Kind Code |
A1 |
Thompson; David L. |
February 12, 2009 |
Closed Loop Medicament Pump
Abstract
A device to determine the level of a substance of interest in a
patient's body and provide a therapeutic amount of medicament is
disclosed. The level of a substance of interest in the patient's
body is determined by iontopheretically sampling the patient's
blood and then analyzing the resulting sample to determine the
level of the substance of interest. The information about the level
of a substance of interest is transmitted to an implanted drug pump
in the patient's body. In the preferred embodiment, the substance
of interest sensor is an external sensor applied to the user's
skin. In an alternate embodiment, the sensor may be implanted. The
preferred method of transmitting information about the level of a
substance of interest determined by the sensor is transmitted to an
implanted drug pump in the patient's body is via a so called "body
bus". The "body bus" is a telemetry system where the patient's own
body provides the interconnection between the iontopheretic device
and the implanted drug pump.
Inventors: |
Thompson; David L.;
(Fridley, MN) |
Correspondence
Address: |
MEDTRONIC MINIMED INC.
18000 DEVONSHIRE STREET
NORTHRIDGE
CA
91325-1219
US
|
Assignee: |
MEDTRONIC MINIMED, INC.
Northridge
CA
|
Family ID: |
23168419 |
Appl. No.: |
12/238875 |
Filed: |
September 26, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10747832 |
Dec 29, 2003 |
7429255 |
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12238875 |
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09302593 |
Apr 30, 1999 |
6669663 |
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10747832 |
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Current U.S.
Class: |
604/891.1 |
Current CPC
Class: |
A61B 5/4839 20130101;
A61B 5/0002 20130101; A61B 5/14532 20130101; A61B 5/0028
20130101 |
Class at
Publication: |
604/891.1 |
International
Class: |
A61K 9/22 20060101
A61K009/22 |
Claims
1.-13. (canceled)
14. A closed loop medicament pump for a patient for sampling and
determining the concentration of a substance of interest and for
determining and delivering a responsive dose of an appropriate
medicament to the patient, wherein the substance of interest
includes glucose and the medicament includes insulin, comprising: a
sensor for sampling and determining the concentration of a
substance of interest including glucose in the patient; a control
system for determining an appropriate response to the determined
concentration of the substance of interest; an implantable drug
pump for dispensing an appropriate amount of a medicament including
insulin to the patient; a first communications system capable of
communicating information, regarding the sensed concentration of a
substance of interest in the patient, from the sensor to the
control system; and a second communications system capable of
communicating information, regarding the determined response to the
determined concentration of the substance of interest, from the
control system to the implantable drug pump.
15. A closed loop medicament pump system according to claim 14
wherein the sensor is an external sensor.
16. A closed loop medicament pump according to claim 14 wherein the
sensor is disposable.
17. A closed loop medicament pump according to claim 14 wherein the
sensor is reusable.
18. A closed loop medicament pump according to claim 14 wherein the
sensor is attached to a flexible substrate.
19. A closed loop medicament pump according to claim 18 wherein the
flexible substrate includes an adhesive to adhere the sensor to
skin of a patient.
20. A closed loop medicament pump according to claim 14 wherein the
control system is a microprocessor.
21. A closed loop medicament pump as in claim 20, wherein the
microprocessor operates a program including the steps of receiving
information related to the concentration of the substance of
interest, comparing the information related to the concentration to
information related to a predetermined limit, and then, if the
comparing step indicates the concentration exceeds the
predetermined limit, determining the appropriate response to the
determined concentration.
22. A closed loop medicament pump as in claim 21 herein the program
further includes the step of generating information to cause the
drug pump to deliver the responsive dose of the appropriate
medicament.
23. A closed loop medicament pump as in claim 21, wherein the
program further includes the step, if the comparing step indicates
the concentration does not exceed the predetermined limit, waiting
for a period of time to expire before again operating the program
steps of receiving information related to the concentration of the
substance of interest and comparing the information related to the
concentration to information related to the predetermined
limit.
24. A closed loop medicament pump as in claim 23, in which the
periodicity of the operation of the program, including the period
of time for waiting, may be present in the program.
25. A closed loop medicament pump as in claim 23, in which the
periodicity of the operation of the program, including the period
of time for waiting, is programmable.
26. A closed loop medicament pump as in claim 21, in which the
operation of the program steps of receiving information related to
the concentration of the substance of interest and comparing the
information related to the concentration to information related to
the predetermined limit may be accomplished on command.
27. A closed loop medicament pump as in claim 21, in which the pump
includes a patient command means and the operation of the program
steps of receiving information related to the concentration of the
substance of interest and comparing the information related to the
concentration to information related to the predetermined limit may
be accomplished on patient command through the patient command
means.
28. A closed loop medicament pump as in claim 20, in which the
microprocessor further includes a memory with a look-up table for
the responsive dose of the appropriate medicament, and the step of
determining the responsive dose includes retrieving a value from
the look-up table.
29. A closed loop medicament pump as in claim 20, in which the
microprocessor further includes a memory with a formula for the
responsive dose of the appropriate medicament, and the step of
determining the responsive dose includes determining the dose
according to the formula.
30. A closed loop medicament pump as in claim 29, in which the
formula includes the variables of the determined concentration of
the substance of interest and the patient's weight.
31. A closed loop medicament pump as in claim 20, in which the drug
pump includes memory, and the information communicated to the pump
to cause the drug pump to deliver the responsive dose of the
appropriate medicament is stored in the memory.
32. A closed loop medicament pump as in claim 31, in which the
information is stored in the memory with related time of the
delivery of the responsive dose.
33. A closed loop medicament pump as in claim 31, in which the
information is stored in the memory with related time of the
delivery of the responsive dose and the memory keeps the
information and time available for later uplink telemetry.
34. A closed loop medicament pump as in claim 33, further
comprising uplink telemetry equipment.
35. A closed loop medicament pump as in claim 14, the drug pump
acting in response to communication to the drug pump by body
bus.
36. A closed loop medicament pump as in claim 14, the drug pump
acting in response to communication to the drug pump by radio
telemetry.
37. A closed loop medicament pump as in claim 14, further
comprising an operatively connected antenna which receives
downlinked telemetry programming data transmitted by an external
programmer.
38. A closed loop medicament pump as in claim 14, further
comprising an operatively connected battery.
39. A closed loop medicament pump as in claim 38, wherein the
battery is a flexible battery.
40. A closed loop medicament pump as in claim 14, in which the
control system is located with the drug pump.
41. A closed loop medicament pump as in claim 14, in which the
control system is located with the sensor.
42. A closed loop medicament pump for a patient for sampling and
determining the concentration of a substance of interest and for
determining and delivering a responsive dose of an appropriate
medicament to the patient, wherein the substance of interest
includes glucose and the medicament includes insulin, comprising:
an external, disposable, reusable sensor for sampling and
determining the concentration of a substance of interest including
glucose in the patient; a control system including a microprocessor
for determining an appropriate response to the determined
concentration of the substance of interest, wherein the
microprocessor operates a program including the steps of receiving
information related to the concentration of the substance of
interest, comparing the information related to the concentration to
information related to a predetermined limit, and then, if the
comparing step indicates the concentration exceeds the
predetermined limit, determining the appropriate response to the
determined concentration, and generating information to cause a
drug pump to deliver the responsive dose of the appropriate
medicament, and if the comparing step indicates the concentration
does not exceed the predetermined limit, waiting for a period of
time to expire before again operating the program steps of
receiving information related to the concentration of the substance
of interest and comparing the information related to the
concentration to information related to the predetermined limit, in
which the periodicity of the operation of the program, including
the period of time for waiting, may be present in the program or
programmed, and in which the operation of the program steps of
receiving information related to the concentration of the substance
of interest and comparing the information related to the
concentration to information related to the predetermined limit may
be accomplished on command, in which the microprocessor further
includes one of either a memory with a look-up table or a formula
for the responsive dose of the appropriate medicament or a memory,
and the step of determining the responsive dose includes one of
retrieving a value from the look-up table or determining the dose
according to the formula; the implantable drug pump for dispensing
an appropriate amount of a medicament including insulin to the
patient, in which the drug pump includes memory, and the
information communicated to the pump to cause the drug pump to
deliver the responsive dose of the appropriate medicament is stored
in the memory with related time of the delivery of the responsive
dose, and the memory keeps the information and time available for
later uplink telemetry; uplink telemetry equipment including an
operatively connected antenna which receives downlinked telemetry
programming data transmitted by an external programmer; a first
communications system capable of communicating information,
regarding the sensed concentration of a substance of interest in
the patient, from the sensor to the control system; a second
communications system capable of communicating information,
regarding the determined response to the determined concentration
of the substance of interest, from the control system to the
implantable drug pump; and an operatively connected battery.
43. A closed loop medicament pump system as in claim 42, in which
the control system is located with the drug pump.
44. A closed loop medicament pump system as in claim 42, in which
the control system is located with the sensor.
Description
RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 10/747,832, filed Dec. 29, 2003, which is a
continuation application of U.S. application Ser. No. 09/302,593,
filed Apr. 30, 1999, now U.S. Pat. No. 6,669,663.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a device for treating physiological
conditions and more particularly relates to a device for treating
diabetes or other physiological conditions through the use of a
closed loop control device for sensing diabetic or other
physiologic states and for delivering an appropriate amount of
insulin or other appropriate medicament or drug, if required, from
an implanted drug pump.
[0004] 2. Description of Related Art
[0005] Diabetes is a disease where the body does not produce or
properly use insulin, a hormone that is needed to convert
carbohydrates such as sugar or starches into energy needed for
daily life. It is not clear what causes diabetes, but both genetics
and environmental factors such as obesity and lack of exercise seem
to play roles.
[0006] There are two major types of diabetes: Insulin-Dependent
(type I) and Non-Insulin-Dependent (type II). It is estimated that
diabetes, in its various forms, affects 16 million people in the
United States alone. In the United States, approximately 1,700
people are diagnosed with diabetes every day with about 625,000
people diagnosed in a year. Type II diabetes is the most common
form of the disease accounting for about 90-95 percent of all
diabetes cases. Type I diabetes accounts for 5-10 percent of all
cases of diabetes.
[0007] Insulin-Dependent (type I) diabetes is an autoimmune disease
where the body does not produce any insulin. This disease occurs
most often in the first two decades of life but can develop up to
about age 40. People with this type of diabetes must take daily
insulin injections to stay alive.
[0008] Non-Insulin-Dependent (type II) diabetes is a metabolic
disorder resulting from the body's inability to make enough of or
properly use insulin. Environmental factors such as obesity and
lack of exercise appear to play a large role in this type of
diabetes. Because many American adults are overweight and don't
exercise, type II diabetes is nearing epidemic proportions in the
U.S. Non-Insulin Dependent diabetes usually gradually develops
after about age 35.
[0009] Diabetes is the fourth-leading cause of death by disease in
the United States. The American Diabetes Association estimates that
more than 169,000 died from the disease and its related
complications in 1997. Some of the complications associated with
diabetes are blindness, kidney disease, nerve disease, amputations,
heart disease and stroke.
[0010] Diabetes is the leading cause of new cases of blindness in
people ages 20-74. Each year, it is estimated that from 12,000 to
24,000 people lose their sight because of diabetes. Ten to
twenty-one percent of all people with diabetes develop kidney
disease. In 1992, an estimated 19,800 people initiated treatment
for end stage renal disease (kidney failure) because of
diabetes.
[0011] In addition, about 60-70 percent of people with diabetes
have mild to severe forms of diabetic nerve damage. In severe
forms, this nerve damage can lead to lower limb amputations.
Diabetes is the most frequent cause of non-traumatic lower limb
amputations. The risk of a leg amputation due to nerve damage is
15-40 times greater for a person with diabetes than for a person
without diabetes. Each year, an estimated 54,000 people lose their
foot or leg to diabetes related amputations.
[0012] People with diabetes are two to four times more likely to
have heart disease than those who don't have diabetes. Heart
disease is present in 75 percent of diabetes-related deaths.
Annually, diabetes related heart disease is estimated to cause more
than 77,000 deaths. Further, people with diabetes are two to four
times more likely to suffer a stroke than people without
diabetes.
[0013] The American Diabetes Association estimates diabetes to be
one of the most costly health problems in America. Health care and
related costs for treatment, as well as the opportunity costs of
lost productivity are estimated to be nearly $92 billion
annually.
[0014] U.S. Pat. No. 5,569,186, issued to Peter C. Lord and Fredric
C. Coleman on Oct. 29, 1996, entitled "Closed Loop Infusion Pump
System with Removable Glucose Sensor" discloses an infusion pump
system having a removable in vivo glucose sensor and an implantable
infusion pump. The glucose sensor determines the concentration of
glucose in the user's blood and then signals the implanted pump to
deliver a selected amount of medication, such as insulin, to the
user. Signaling is accomplished via a direct or telemetric
connection between the sensor and the pump.
[0015] U.S. Pat. No. 5,279,543, issued to Glikfeld et al. on Jan.
18, 1994, discloses an iontopheretic device to determine the level
of glucose in a user's body combined with an insulin pump or
iontopheretic delivery system and feedback to administer
appropriate levels of a insulin to diabetic patients.
[0016] It has been a goal of those developing medical devices to
treat diabetes to produce a fully implantable system that mimics
the body's own system for regulating glucose. Such a system would
require a sensor to sense the level of glucose in the blood, a
device to infuse insulin or similar hormone to control the level of
glucose and means for relaying the results of the glucose sensed to
the device to infuse insulin so that a closed loop is formed. In
this way, the system would automatically react to different levels
of glucose and provide an appropriate level of insulin.
[0017] Unfortunately, such a fully implantable system has not yet
been created. Much work has been done to develop ChemFETs and other
sensors that can detect the level of glucose in the blood. However,
when implanted, these sensors only have a lifespan of a few days at
best. To be practical, implantable sensors to detect the level of
glucose in the blood need to have a lifespan of at least several
months.
SUMMARY OF THE INVENTION
[0018] A device to determine the level of glucose in a patient's
body and provide a therapeutic amount of insulin or a similar drug
is disclosed. The level of glucose in the patient's body is
determined by painlessly iontopheretically sampling the patient's
blood and then analyzing the resulting sample to determine the
level of glucose. The information about the level of glucose is
transmitted to an implanted drug pump in the patient's body. In the
preferred embodiment, the glucose sensor is an external sensor
applied to the user's skin. In an alternate embodiment, the sensor
may be implanted. The preferred method of transmitting information
about the level of glucose determined by the sensor is transmitted
to an implanted drug pump in the patient's body is via a so called
"body bus". The "body bus" is a telemetry system where the
patient's own body provides the interconnection between the
iontopheretic device and the implanted drug pump.
[0019] It is therefore a primary object of the invention to provide
a system that mimics the body's own system for administering an
appropriate dose of insulin.
[0020] It is another object of one embodiment of the invention to
provide a system that mimics the body's own system for
administering an appropriate dose of insulin including an external
sensor.
[0021] These and other objects of the invention will be clear from
the description of the invention given herein and particularly with
reference to the attached drawings and the Detailed Description of
the Invention. Throughout this description, like reference numbers
refer to like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a perspective schematic view of the present
invention in use on a patient's body.
[0023] FIG. 2 is a block diagram of the preferred embodiment of the
present invention.
[0024] FIG. 3 is a block diagram of another embodiment of the
present invention.
[0025] FIG. 4 is a plan view of a sensor of the present
invention.
[0026] FIG. 5 is a side view of the sensor of FIG. 4.
[0027] FIG. 6 is a flow chart of the preferred operation of the
control system of the present invention that corresponds the
embodiment shown in FIG. 2.
[0028] FIG. 7 is a flow chart of an alternate operation of the
control system of the present invention that corresponds the
embodiment shown in FIG. 3.
[0029] FIG. 8 is a perspective schematic view of an alternate
embodiment of the present invention in use in a patient's body.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Referring to FIG. 1, the invention is shown generally
labeled 10. The invention 10 includes a sensor module 12, a control
system 14, a sensor telemetry system 16, a pump telemetry system 18
and an implantable drug pump 20.
[0031] In the preferred embodiment, the purpose of sensor module 12
is to non-invasively sample glucose from blood, determine the
concentration of glucose in the blood, determine the appropriate
dose of insulin to be administered to the user and communicate the
determined dose to an implantable drug pump 20. Consequently, the
glucose sampling and glucose concentration determining function of
sensor module 12 is performed by two parts, a sampling system 22
and a concentration determining system 24. The non-invasive glucose
sampling is preferably performed by sampling system 22 by
iontopheretically removing glucose from blood through the skin. The
preferred device for sampling system 22 is shown in U.S. Pat. No.
5,730,714 issued on Mar. 28, 1998 to Richard Guy, Girish Rao,
Peretz Glikfeld, Christopher Cullander and Robert S. Hinz entitled
"Method for the Iontopheretic Non-Invasive Determination of the In
Vivo Concentration of Glucose", the teaching of which is
incorporated herein in its entirety. Other examples of
iontopheretic sampling parts 22 to remove glucose molecules through
the skin that could be used in the present invention are disclosed
in U.S. Pat. No. 4,406,658 issued on Sep. 27, 1983 to Gary A.
Lattin and Richard Spevak entitled "Iontopheretic Device with
Reversible Polarity", U.S. Pat. No. 5,279,543 issued on Jan. 18,
1994 to Peretz Glikfield, Christopher Cullander, Robert S. Hinz and
Richard H. Guy entitled "Device for Iontopheretic Non-Invasive
Sampling or Delivery of Substances" and U.S. Pat. No. 5,362,307
issued on Nov. 8, 1994 to Richard Guy and Girish Rao entitled
"Method for the Iontopheretic Non-Invasive Determination of the In
Vivo Concentration Level of an Inorganic or Organic Substance", the
collective teachings of which are incorporated herein by reference
in their entirety.
[0032] The preferred device for the concentration determining
system 24 is also shown in the herein above referenced '714 patent
to Guy et al. Another device for the concentration determining
system 24 is disclosed in an article by Joseph Black, Michael
Wiliness, Platen Atanasov and Ebtisam Wiliness entitled "Integrated
sensor-telemetry system for in vivo glucose monitoring" (Sensors
and Actuators B 31 (1996) 147-153), the teaching of which is
incorporated herein by reference in its entirety.
[0033] Sensor module 12 is preferably an external sensor that is
placed on the skin of the patient. In the preferred embodiment,
sensor module 12 is intended to be disposable. In this way, an
"old" sensor module 12 can be conveniently and easily removed and
replaced with a "new" sensor module 12, for example, daily. In
another embodiment, the sensor module 12 may be reusable. In this
embodiment, sensor module 12 would be capable of being cleaned in
ways well known to those in the art such as by autoclaving.
[0034] Sensor module 12 is attached to a flexible substrate 26
(FIG. 4). Flexible substrate 26 has a patient contact side 28 and
an instrumentation side 30. In particular, a pair of electrodes 32
that are part of the sampling system 22 are attached to the contact
side 28 of flexible substrate 26 to come into contact with a user's
skin. The contact side 28 has an adhesive that allows flexible
substrate 26 to be removably attached to the skin of the user. The
adhesive should be strong enough to cause the sensor module 12 to
adhere to the skin of the patient but not so strong as to make it
difficult to remove the sensor module 12 when desired as will be
explained hereafter. The adhesive should also not be susceptible to
iontopheresis. An example of such an adhesive is as substantially
described in U.S. Pat. Nos. 5,489,624 and 5,536,768, both titled
"Hydrophyllic Pressure Sensitive Adhesives" issued Feb. 6, 1996 and
Jul. 16, 1996, respectively to Steven S. Kentner, Nancy J. Rustad
and James S. Stabely, the collective teachings of which are
incorporated herein by reference in their entireties.
[0035] Flexible substrate 26 may have a size and shape similar to
that of commercially available disposable bandages. In one
embodiment, flexible substrate 26 has a width dimension ranging
between approximately 0.5'' and approximately 3'', and a length
dimension ranging between approximately 3/4'' and approximately
5''. Although the preferred embodiment of flexible substrate 26 is
substantially rectangular, virtually any other shape for flexible
substrate 26 is within the scope of the invention. For example,
additional possible shapes for flexible substrate 26 include, but
are not limited to, square, round and oval.
[0036] Instrumentation side 30 is on the opposite side of flexible
substrate 26 than patient contact side 28. Instrumentation side 30
provides a surface for mounting the components of sensor module 12.
In the embodiment illustrated in FIG. 4, flexible substrate 26 may
comprise a resilient material upon which several electronic and
electrical components are mounted. Flexible substrate 26 may
include an integral or separate interconnect pattern of electrical
conductors that provide for interconnection between the various
components disposed on flexible substrate 26. Suitable materials
that may be used to fabricate flexible substrate 26 include mylar,
flexible foil, flex PC, Kapton and polymer thick film (PTF).
[0037] The components mounted to instrumentation side 30 include,
in the preferred embodiment, the sampling system 22 and
concentration determining system 24 of sensor 12, a battery 34, the
control system 14 and the sensor telemetry system 16. Shown
surrounding the components mounted to the instrument side 30 is an
antenna 40 which receives downlinked telemetry programming data
transmitted by an external programmer (not shown). Battery 34 is
preferably mounted to flexible substrate 26 and powers sensor
module 12, control system 14 and sensor telemetry system 16.
Battery 34 is preferably a flexible battery such as a lithium
manganese oxide (e.g., LiMnO.sub.2) chemistry and may be of a
sealed foil or plastic battery. In this way, battery 34 can bend
with flexible substrate 26 as sensor module 12 is applied to the
skin. Examples of such flexible batteries are disclosed in U.S.
Pat. No. 5,558,957 issued to Madhav Datta and Ravindra V. Shenoy on
Sep. 24, 1996 entitled "Method for Making a Thin Flexible Primary
Battery for Microelectronics Applications" and U.S. Pat. No.
5,326,652 issued to Rickie C. Lake on Jul. 5, 1994 entitled
"Battery Package and Method Using Flexible Polymer Films Having a
Deposited Layer of an Inorganic Material", the collective teachings
of which are incorporated herein by reference.
[0038] Control system 14 is preferably a microprocessor such as a
low cost PIC microcontroller from Microchip Technology of Chandler,
Ariz. Control system 14 is connected to concentration determining
system 24 to receive information about the concentration of glucose
determined by the concentration determining system 24. Control
system 14 processes information from the concentration determining
system 24 and determines an appropriate response according to the
process shown in the flow chart of FIG. 6 as will be explained
below.
[0039] A protective cover 36 attaches to and covers the components
of sensor module 12. The function of protective cover 36 is to
cover and protect the components on flexible substrate 26. As such,
protective cover is preferable also flexible to allow strip 26 to
be conformably attached to the patient's skin.
[0040] As mentioned, the invention includes an implantable pump 20.
Pump 20 stores and delivers insulin or other appropriate drug to
the patient through a catheter in response to the information
provided from sensor module 12. Pump 20 is preferably a peristaltic
pump such as that disclosed in U.S. Pat. No. 4,692,147, issued on
Sep. 8, 1987 to Stephen R. Duggan entitled "Drug Administration
Device", the teachings of which are incorporated herein in its
entirety. Such a pump is the Synchromed.RTM. Drug Pump,
manufactured by Medtronic, Inc. of Minneapolis, Minn. modified as
described in the '897 patent to receive information from sensor
module 12. Catheter 38 may be the models 8700A, 8700B, 8702 or 8770
manufactured by Medtronic, Inc. of Minneapolis, Minn.
[0041] Although a peristaltic drug pump is preferred, any type of
implantable pump may be used and is within the scope of the
invention. Examples of alternate types of pumps 200 are disclosed
in U.S. Pat. No. 4,714,462, issued on Dec. 22, 1987 to Robert A.
DiDomenico and entitled "Positive Pressure Programmable Infusion
Pump" and U.S. Pat. No. 4,838,887, issued on Jun. 13, 1989 to Samir
F. Idriss and entitled "Programmable Valve Pump", the teachings of
which are incorporated herein in their entirety.
[0042] In FIG. 6, information about the determined concentration of
glucose by sensor 12 is presented to step 40. The program passes
from step 40 to step 42. Step 42 periodically compares the
concentration of glucose presented at step 40 to a predetermined
limit. The predetermined limit may be preset or set by downloading
a desired limit. If the determined concentration in step 40 exceeds
the predetermined limit, the program passes to step 44. If the
determined concentration in step 40 does not exceed the preset
limit, no action is taken and step 42 proceeds to step 46 to wait
for an appropriate period to expire before passing to step 42 to
again compare a newly determined concentration of glucose to the
predetermined limit.
[0043] In this embodiment, the determined concentration of glucose
presented at step 40 is periodically compared to predetermined
limit in step 42. The periodicity may be preset in the programming
or may be programmable to any desired period. In addition, the
comparison of the determined concentration of glucose may be
accomplished on command as for example by activating the comparison
of step 42 in response to a user command for example, based upon
time or when about to consume food. Such a user command may take
the form of activating a reed switch with a magnet, activating an
electronic switch with a radio signal, mechanically actuating a
switch by palpating the switch through the skin or many other forms
that will occur to those skilled in the art; the key function of
whatever action being to cause the step 42 to immediately compare
the determined concentration of glucose presented at step 40 to a
predetermined limit.
[0044] At step 44, the appropriate response to the high
concentration of glucose is determined. The most likely appropriate
response will be to activate the pump 20 to infuse an amount of
insulin or other appropriate drug into the patient's blood stream.
The amount of insulin to infuse may be determined by a formula or
from a value retrieved in a look-up table prepared by the patient's
physician. If the determined amount of insulin is determined by
formula, the formula would include the variables of the determined
concentration of glucose and the patient's weight as will be clear
to those skilled in the art.
[0045] If the determined amount of insulin is determined from a
look-up table, an appropriate responsive dose of insulin
corresponding to a measured concentration of glucose and possible
other variables such as the patient's weight, would be stored in
the look-up table. Once the measured concentration of glucose were
determined, the responsive dose of insulin would be retrieved from
the look-up table.
[0046] It is intended in this embodiment that control system 14
perform steps 42, 44 and 46.
[0047] Once the responsive dose of insulin has been determined from
either a formula or a look-up table, the program passed to step 48.
Step 48 communicates the responsive dose to the pump 20 and the
program passed to step 50. The responsive dose values communicated
to the pump 20 may be transmitted to the pump 20 and stored in
internal RAM memory along with the related times of the determined
doses for later uplink telemetry to a follow-up physician. Step 50
receives the responsive dose communicated from step 48 and passes
it to the pump 20. The responsive dose is preferably communicated
to the pump 20 by passing the appropriate responsive dose to the
pump 20 through sensor telemetry module 16 (at step 48) and pump
telemetry module 18 (at step 50).
[0048] Sensor telemetry module 16 is attached to flexible substrate
26. Sensor telemetry module 16 receives information about the
appropriate amount of insulin to infuse into the user by pump 20 at
step 44 and conveys it to pump telemetry module 18 where it is
received at passed to the pump 20 at step 50. Pump 20 then infuses
the appropriate amount of insulin to the patient at step 52. In the
preferred embodiment, sensor telemetry module 16 and pump telemetry
module 18 communicate using the body of the user itself to convey
the information utilizing the electrode 32 of FIG. 4. This type of
communication is sometimes referred to a "body-bus"
communication.
[0049] An example of such a "body-bus" communication system is
given in U.S. Pat. Nos. 4,987,897 and 5,113,859, issued to Hermann
D. Funke on Jan. 29, 1991 and May 19, 1992, entitled "Body Bus
Medical Device Communication System" and "Acoustic Body Bus Medical
Device Communication System" respectively, the teachings of which
are incorporated herein by reference in its entirety. Alternately,
a radio frequency telemetry approach as described in U.S. Pat. No.
5,683,432 to Goedeke may be used. In this alternate embodiment,
antenna 40 would be used to communicate to pump 20.
[0050] At step 50, the appropriate dose information is received and
passed to pump 20. The program passes to step 52 where the pump
administers the appropriate dose to the user. From step 52, the
program passes back to step 42 to compare the newly determined
concentration of glucose presented at step 40 to the predetermined
limit.
[0051] An alternate embodiment of the invention is shown in FIG. 3,
the operation of which is shown in FIG. 7. In this embodiment,
control system 14 is located with pump 20 instead of on flexible
substrate 26. It is intended that control system 14 in this
embodiment be part of the microprocessor or other control system
that controls the operation of pump 20. However, it is also an
alternate embodiment of this embodiment that the control system 14
may be a separate unit distinct from the microprocessor or other
control system that controls the operation of pump 20. The key here
being that the control system 14 is located with the pump 20
instead of with the flexible substrate 26.
[0052] In operation, this alternate embodiment operates as
described above beginning with step 40 where the concentration of
glucose determined by the sensor module 12 is presented. The
program passes to step 54 where the concentration of glucose is
communicated to the pump 20 via sensor telemetry module 16. The
glucose concentration values communicated to the pump 20 may be
transmitted to the pump 20 and stored in internal RAM memory along
with the time of the determined concentration for later uplink
telemetry to a follow-up physician. The program passes to step 56.
Step 56 receives the concentration of glucose communicated from
step 54 by pump telemetry module 18 and passes it to control system
14. Here, as above, communication between the sensor module 12 and
pump 20 is accomplished by the sensor telemetry module 16 and the
pump telemetry module 18 as described above. The difference in this
embodiment being only that the information conveyed between the
sensor module 12 and pump 20 here is the concentration of glucose
determined by the sensor module 12 instead of the appropriate
dosage of insulin to be administered to the patient.
[0053] From step 56, the program passes to step 58. Step 58, in
similar fashion to step 42, periodically compares the concentration
of glucose presented at step 56 to a predetermined limit. If the
determined concentration in step 56 exceeds the predetermined
limit, the program passed to step 60. If the determined
concentration in step 56 does not exceed the preset limit, no
action is taken and step 58 proceeds to step 62 to wait for the
appropriate period to expire before passing to step 58 to again
compare a newly determined concentration of glucose received from
sensor module 12 to the predetermined limit.
[0054] In this embodiment as in the preferred embodiment described
above, the determined concentration of glucose is periodically
compared to predetermined limit. The periodicity may be preset in
the programming or may be programmable to any desired period. In
addition, the comparison of the determined concentration of glucose
may be accomplished on command as for example by activating the
comparison of step 42 in response to a user command. As above, such
a user command may take the form of activating a reed switch with a
magnet, activating an electronic switch with a radio signal,
mechanically actuating a switch by palpating the switch through the
skin or many other forms that will occur to those skilled in the
art; the key function of whatever action being to cause the step 58
to immediately compare the determined concentration of glucose to a
predetermined limit.
[0055] At step 60, the appropriate response to the high
concentration of glucose is determined. The most likely appropriate
response will be to activate the pump 20 to infuse an amount of
insulin or other appropriate drug into the patient's blood stream.
Again, the amount of insulin to infuse may be determined by a
formula or from a value retrieved in a look-up table. If the
determined amount of insulin is determined by formula, the formula
would include the variables of the determined concentration of
glucose and the user's weight as will be clear to those skilled in
the art.
[0056] If the determined amount of insulin is determined from a
look-up table, an appropriate responsive dose of insulin
corresponding to a measured concentration of glucose would be
stored in the look-up table. The appropriate responsive dose would
be determined based on the person's weight or other factors which
will occur to those skilled in the art. Once the measured
concentration of glucose is determined, the responsive dose of
insulin is retrieved from the look-up table.
[0057] Once the responsive dose of insulin has been determined from
either a formula or a look-up table, the program passed to step 64.
At step 64, the appropriate dose information is administered to the
user by pump 20. From step 64, the program passes back to step
58.
[0058] In the preferred embodiment, sensor 12 is an external sensor
applied to the skin of the user. In an alternate embodiment shown
in FIG. 8, sensor module 12 is implanted in the user as shown in
the '186 patent issued to Peter C. Lord and Fredric C. Coleman
discussed above.
[0059] In this embodiment, battery 34 may be used or may be
replaced with a rechargeable battery or a "super-capacitor" to
provide power to sensor module 12. Examples of appropriate
rechargeable batteries include, but are not limited to lithium
batteries, nickel-metal hydride, lithium polymer, nickel cadmium
and rechargeable alkaline manganese dioxide. With respect to
rechargeable batteries, the teaching of U.S. Pat. No. 5,661,393
issued on Aug. 26, 1997 to Upal Sengupta entitled "Circuit and
Method for Detecting and Indicating the State of Charge of a Cell
or Battery" is incorporated herein by reference in its entirety.
Examples of "super-capacitor" power providing systems are shown in
U.S. Pat. Nos. 5,591,217 issued to Francisco J. Barreras on Jan. 7,
1997 entitled "Implantable Stimulator with Replenishable High Value
Capacitive Power Source and Method Therefor" and U.S. Pat. No.
5,733,313 issued to Francisco Jose Barreras, Sr. and Oscar Jimenez
on Mar. 31, 1998 entitled "RF Coupled Implantable Medical Device
with Rechargeable Back-up Power Source". The collective teachings
of these patents are incorporated herein by reference.
[0060] The invention has been described primarily in connection
with a device to detect glucose and deliver an appropriate response
of insulin to the patient's body. It is also within the scope of
the invention to detect other biological chemicals, enzymes,
hormones, etc. and deliver an appropriate response of an
appropriate therapeutic agent if needed. For example, the sampling
system 22 and a concentration determining system 24 of the
invention can also be used to sample and determine the
concentration of the substances disclosed in Table 4 of the '714
Guy et al. patent, the teaching of which, including the discussion
in column 12, lines 23-64, is incorporated herein by reference. In
this embodiment, a particular substance of interest is sampled and
its concentration determined, thereby indicating the presence and
severity of a particular condition or disease as for example is
shown in Table 4 of the '714 Guy et al. patent. Thereafter, the
present invention delivers, as described above, an appropriate
amount of an appropriate medicament or drug to the patient
according to sound medical judgment. The description contained
herein is intended to be illustrative and not exhaustive. Many
variations and alternatives will occur to one of ordinary skill in
this art. All these alternatives and variations are intended to be
included within the scope of the attached claims. Those familiar
with the art may recognize other equivalents to the specific
embodiments described herein which equivalents are also intended to
be encompassed by the claims attached hereto.
* * * * *