U.S. patent application number 10/678698 was filed with the patent office on 2005-06-02 for apparatus and method for preventing free flow in an infusion line.
Invention is credited to Beck, Kent F., Malmstrom, James, Miles, Scott.
Application Number | 20050119625 10/678698 |
Document ID | / |
Family ID | 24274983 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050119625 |
Kind Code |
A1 |
Miles, Scott ; et
al. |
June 2, 2005 |
Apparatus and method for preventing free flow in an infusion
line
Abstract
An apparatus and method for preventing free flow through an
infusion set utilizes an occluder disposed within the infusion set
to selectively prevent flow therethrough. The occluder may be
responsive to a pressure differential within the infusion set or
may respond to compression of the infusion set. When a pair of
occluders are used in sequence, an in-line pump may be formed.
Inventors: |
Miles, Scott; (Sandy,
UT) ; Beck, Kent F.; (Layton, UT) ; Malmstrom,
James; (Kaysville, UT) |
Correspondence
Address: |
RANDALL B. BATEMAN
BATEMAN IP LAW GROUP
8 EAST BROADWAY, SUITE 550
PO BOX 1319
SALT LAKE CITY
UT
84110
US
|
Family ID: |
24274983 |
Appl. No.: |
10/678698 |
Filed: |
October 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10678698 |
Oct 3, 2003 |
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10121080 |
Apr 12, 2002 |
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10121080 |
Apr 12, 2002 |
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09569332 |
May 11, 2000 |
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6595950 |
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Current U.S.
Class: |
604/246 |
Current CPC
Class: |
A61M 39/281 20130101;
A61M 39/287 20130101; A61M 5/14232 20130101; A61M 2039/248
20130101; A61M 39/24 20130101; A61M 5/14 20130101; A61M 2039/2473
20130101; A61M 5/16813 20130101; A61M 2039/2486 20130101; A61M
2039/2426 20130101; Y10T 137/87917 20150401; A61M 2205/12 20130101;
A61M 5/142 20130101; A61M 39/22 20130101; A61M 5/14228 20130101;
A61M 2039/242 20130101 |
Class at
Publication: |
604/246 |
International
Class: |
A61M 005/00 |
Claims
1-81. (canceled)
82. A valve for controlling fluid flow, the valve comprising: an
elongate flexible infusion line configured for carrying liquids,
the infusion line having a proximal portion, a middle portion, and
a distal portion; a first occluder disposed in the infusion line
for selectively preventing flow of liquid from the proximal portion
to the middle portion; a second occluder disposed in the infusion
line for selectively preventing flow of liquid from the middle
portion to the distal portion; and a first actuator associated with
and upstream of the first occluder, adjacent the proximal portion
of the infusion line for selectively applying force to the proximal
portion of the infusion line to enable fluid flow from the proximal
portion to the middle portion past the first occluder.
83. The valve according to claim 82, further comprising: a second
actuator adjacent the middle portion of the infusion line and
associated with the second occluder for selectively applying force
to the middle portion of the infusion line to enable fluid flow
from the middle portion to the distal portion past the second
occluder.
84. The valve according to claim 83, further comprising a drive
means for moving the first actuator and the second actuator.
85. The valve according to claim 82, wherein the infusion line is
formed from a resilient material, and wherein application of force
by the first actuator against the infusion line forms a flow
channel between the infusion line and the first occluder.
86. The valve according to claim 83, wherein the infusion line is
formed from a resilient material, and wherein application of force
by the second actuator against the infusion line forms a flow
channel between the infusion line and the second occluder.
87. The valve according to claim 82, further comprising a second
force actuator disposed adjacent the first occluder for selectively
applying force to the infusion line adjacent the first occluder to
enable fluid flow past the first occluder.
88. A valve for controlling fluid flow, the valve comprising: an
elongate flexible infusion line configured for carrying liquids,
the infusion line having a proximal portion, and a distal portion;
a first occluder disposed in the infusion line for selectively
preventing flow of liquid from the proximal portion toward the
distal portion; and a first actuator associated with and upstream
of the first occluder adjacent the proximal portion of the infusion
line for selectively applying force to the infusion line to enable
fluid flow from the proximal portion toward the distal portion and
past the first occluder.
89. The valve for controlling fluid flow according to claim 82,
wherein the valve further comprises a second occluder disposed
downstream from the first occluder.
90. The valve for controlling fluid flow according to claim 89,
wherein the infusion line has a middle portion disposed between the
first occluder and the second occluder, and wherein actuating the
first actuator moves fluid into the middle portion.
91. The valve for controlling fluid flow according to claim 89,
further comprising: a second actuator for selectively applying
force to the middle portion of the infusion line to enable fluid
flow from the middle portion to the distal portion past the second
occluder.
92. The valve for controlling fluid flow according to claim 91,
wherein the second actuator applies a compressive force to the
infusion line and thereby causes radial expansion to the infusion
line adjacent the second occluder.
93. The valve for controlling fluid flow according to claim 91,
wherein the first actuator applies a compressive force to the
infusion line and thereby causes radial expansion to the infusion
set adjacent the first occluder.
94. The valve according to claim 91, further comprising a drive
means for moving the first actuator and the second actuator.
95. The valve according to claim 89, wherein the infusion line is
formed from a resilient material, and wherein application of force
by the first actuator against the infusion line forms a flow
channel between the infusion line and the first occluder.
96. The valve according to claim 91, wherein the infusion line is
formed from a resilient material, and wherein application of force
by the second actuator against the infusion line forms a flow
channel between the infusion line and the second occluder.
97. The valve according to claim 91, further comprising a third
force actuator associated with and disposed adjacent the first
occluder and a fourth force actuator associated with and disposed
adjacent the second occluder for applying force to the infusion
line adjacent the first and second occluders to enable fluid flow
past the occluders.
98. A valve for controlling fluid flow, the valve comprising: an
elongate flexible infusion line configured for carrying liquids,
the infusion line having a proximal portion, a middle portion and a
distal portion; a first occluder disposed in the infusion set for
selectively preventing flow of liquid from the proximal portion to
the middle portion and allowing flow when a predetermined pressure
exists in the proximal portion; a second occluder disposed in the
infusion set for selectively preventing flow from the middle
portion to the distal portion and allowing flow when a
predetermined pressure exists in the middle portion wherein the
predetermined pressure is different than the predetermined pressure
at which flow is allowed past the first occluder; and an actuator
for applying a force to the middle portion to force fluid in the
middle portion to pass the second occluder and flow into the distal
portion.
99. The valve according to claim 98, further comprising another
actuator associated with and upstream of the first occluder for
selectively applying force to the proximal portion of the infusion
line to enable fluid flow from the proximal portion to the middle
portion.
100. The valve according to claim 99, further comprising a drive
mechanism for moving the actuators.
101. The valve according to claim 82, further comprising a third
force actuator associated with and disposed adjacent the first
occluder and a fourth force actuator associated with and disposed
adjacent the second occluder for selectively applying force to the
infusion line adjacent the first and second occluders to enable
fluid flow past the first and second occluders.
102. The valve according to claim 91, further comprising a third
force actuator associated with and disposed adjacent the first
occluder and a fourth force actuator associated with and disposed
adjacent the second occluder for applying force to the infusion
line adjacent the first and second occluders to create a flow
channel between the infusion line and the occluders.
103. The valve according to claim 88, further comprising a second
force actuator associated with and disposed adjacent the first
occluder for applying force to the infusion line adjacent the first
occluder to enable fluid flow past the occluder.
104. The valve according to claim 88, further comprising a second
force actuator associated with and disposed adjacent the first
occluder for applying force to the infusion line adjacent the first
occluder to create a flow channel between the infusion line and the
occluder.
105. The valve according to claim 98 further comprising a second
actuator associated with and disposed adjacent the first occluder
for applying force to the infusion line at the first occluder to
enable fluid flow past the occluder.
106. The valve according to claim 98 further comprising a second
actuator associated with and disposed adjacent the first occluder
for applying force to the infusion line at the first occluder to
create a flow channel around the first occluder.
107. The valve according to claim 99 further comprising a third
actuator associated with and disposed adjacent the first occluder
and a fourth actuator associated with and disposed adjacent the
second occluder for applying force to the infusion line at the
first and second occluders to allow flow around the occluders.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus and method for
preventing free flow during enteral or parenteral administration
solutions through an infusion line. More particularly, the present
invention relates to an occluder/valve and method of use for
infusion sets and the like, wherein the occluder/valve prevents
undesirable free-flow of solution through the infusion set while
allowing controlled flow through the infusion set.
[0003] 2. State of the Art
[0004] The use of infusion sets to administer solutions to patients
is well known in the medical arts. Infusion sets are used for both
enteral and parenteral applications. Enteral feeding pumps are used
to provide patients with nutrition and medication when they are
unable, for a variety of reasons, to eat normally. Parenteral
(intravenous) solutions are provided to patients to ensure adequate
hydration and to provide needed nutrients, minerals and medication.
Often, the infusion set is placed in a free standing arrangement in
which gravity forces the solution into the patient. The rate at
which the solution enters the patient can be roughly controlled by
various clamps, such as roller clamps, which are currently
available on the market.
[0005] In many applications, it is necessary to precisely control
the amount of solution which enters the patient. When this is the
case, a regulating device, such as an enteral feeding pump, is
placed along the infusion set to control the rate at which the
solution is fed to the patient. In applications where a pump, etc.,
is used, the clamps used to regulate flow are typically opened to
their fullest extent to prevent the clamp from interfering with the
proper functioning of the pump. The clamp is opened with the
expectation that the enteral feeding pump will control fluid flow
through the infusion set. However, emergencies or other
distractions may prevent the medical personnel from properly
loading the infusion set in the enteral feeding pump.
[0006] When the infusion set is not properly loaded in the pump and
the clamp has been opened, a situation known as free-flow often
develops. The force of gravity causes the solution to flow freely
into the patient unchecked by the pump or other regulating device.
Under a free-flow condition, an amount of solution many times the
desired dose can be supplied to the patient within a relatively
short time period. This can be particularly dangerous if the
solution contains potent medicines and the patient's body is not
physically strong enough to adjust to the large inflow of
solution.
[0007] Numerous devices have been developed in an attempt to
prevent free flow conditions. Such devices, however, typically add
significantly to the overall cost of the infusion set and some
provide only marginal protection against free flow.
[0008] Thus, there is a need for a device that prevents a free-flow
condition while allowing controlled flow through the infusion set.
There is also a need for such a device which prevents free-flow if
an infusion set is not properly mounted in a pump or other
regulating means.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide an
apparatus and method for occluding infusion sets to prevent an
accidental free-flow condition.
[0010] It is another object of the present invention to provide an
occluder which is simple to make and use.
[0011] It is another object of the present invention to provide
such an occluder which is inexpensive and thus disposable.
[0012] It is still another object of the present invention to
provide an occluder which occludes fluid flow through the infusion
set unless the infusion set is properly loaded in a flow control
mechanism such as an enteral feeding pump.
[0013] It is still yet another object of the present invention to
provide such an occluder which allows for a simple manual override
of the occluding function.
[0014] It is still yet another aspect of the invention to provide
an occluder which functions as a valve to effectively control fluid
flow through a flexible conduit.
[0015] The above and other objects of the invention are realized in
an apparatus and method for preventing free flow in an infusion
set. In accordance with one aspect of the invention, an occluder is
disposed within the infusion set. The occluder is configured to
prevent free flow of fluids in the infusion set past the occluder.
The occluder is also configured, however, selectively to allow
solutions to pass by the occluder which are pumped by an enteral
feeding pump and the like.
[0016] In accordance with one embodiment of the invention, the
occluder is formed by a stop placed in the tubing of the infusion
set. The stop limits flow around and/or through the stop when the
solution is subject to flow due to gravity. However, when greater
pressures are placed on the solution, such as those produced by a
pump, the solution is able to flow around and/or through the stop,
thereby delivering the solution to the patient.
[0017] In accordance with another embodiment of the present
invention, an occluding valve is disposed in the infusion set. The
valve prevents free flow through the infusion set due to gravity,
while allowing controlled flow of solution through the infusion
set.
[0018] In accordance with another aspect of the invention, the
occluder is configured to stop fluid flow until the infusion set
has been properly loaded into a control mechanism such as a pump.
Once properly placed, the interaction between the occluder and the
infusion set effectively opens the infusion set to allow solution
to flow therethrough.
[0019] In accordance with still another aspect of the present
invention, the occluder can be formed integrally with the infusion
set or can be formed of independent piece (s) which are then placed
in the infusion set to selectively occlude the flow of solution
therethrough.
[0020] In accordance with still yet another aspect of the
invention, the occluder can function as a valve to selectively
allow fluid flow therethrough. In one embodiment, a pair of
occluders and infusion line can be used in conjunction with a
piston or other force applicator to form a linear peristaltic pump
which delivers predetermined amounts of fluid to a patient.
[0021] In accordance with still yet another aspect of the present
invention, the occluder and infusion line can be formed to nest in
and be opened by a conventional fluid flow pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The above and other objects, features and advantages of the
invention will become apparent from a consideration of the
following detailed description presented in connection with the
accompanying drawings in which:
[0023] FIG. 1 shows an perspective view of an infusion set made in
accordance with the prior art;
[0024] FIG. 2A shows a fragmented, side cross-sectional view of an
apparatus and method for preventing free-flow through an infusion
set in the form of an occluder mounted in an infusion set with the
occluder and infusion set in a closed configuration;
[0025] FIG. 2B shows a fragmented, side cross-sectional view of
similar to that of FIG. 2A, wherein the occluder and infusion set
are in an open configuration;
[0026] FIG. 2C shows a fragmented, side cross-sectional view of an
alternate occluder/infusion set configuration made in accordance
with the principles of the present invention;
[0027] FIG. 3A shows a fragmented, side cross-sectional view of an
alternate apparatus and method for preventing free-flow through an
infusion set in accordance with the principles of the present
invention;
[0028] FIG. 3B shows a fragmented, cross-sectional view of an
alternate occluder embodiment, with the occluder and infusion set
being disposed in a closed configuration;
[0029] FIG. 3C shows a cross-sectional view of the occluder
embodiment of FIG. 3A with the occluder and infusion set being
disposed in an open configuration;
[0030] FIG. 3D shows a fragmented, side cross-sectional view of
another embodiment of an occluder and infusion set made in
accordance with the principles of the present invention;
[0031] FIG. 3E shows a fragmented, side cross-sectional view of
still yet another embodiment of an occluder and infusion set made
in accordance with the principles of the present invention;
[0032] FIG. 4A shows fragmented, side cross-sectional view of
another embodiment of an occluder and infusion set with the
occluder in an closed configuration;
[0033] FIG. 4B shows a cross-sectional view of the embodiment of
FIG. 4A in an open configuration;
[0034] FIG. 5A shows fragmented side cross-sectional view of an
occluder and infusion set made in accordance with one aspect of the
present invention with the occluder and infusion set being in a
closed position;
[0035] FIG. 5B shows a cross-sectional view taken along plane A-A
of FIG. 5A;
[0036] FIG. 5C shows a fragmented, side cross-sectional view of an
infusion set with an occluder disposed therein, with the infusion
set being mounted in a control mechanism to maintain the infusion
set and occluder in an open configuration;
[0037] FIG. 5D shows a cross-sectional view taken along the plane
B-B of FIG. 5C;
[0038] FIG. 5E shows a perspective view of a housing of a control
mechanism as may be used to hold the infusion set and occluder in
an open position as shown in FIG. 5D;
[0039] FIG. 6A shows a fragmented, side cross-sectional view of an
infusion set having an occluder formed therein in accordance with
an aspect of the present invention;
[0040] FIG. 6B shows a view similar to that shown in FIG. 6A with
the occluder held in an open position.
[0041] FIG. 7 shows another configuration of an occluder made in
accordance with the principles of the present invention.
[0042] FIG. 8 shows yet another configuration of an occluder made
in accordance with the principles of the present invention;
[0043] FIG. 8A shows a cross-sectional view of another
configuration of an occluder in accordance with the present
invention;
[0044] FIG. 8B shows a cross-sectional view of still yet another
configuration of an occlude of the present invention;
[0045] FIG. 9 shows yet another aspect of the invention wherein the
occluder forms part of a liquid control valve.
[0046] FIG. 10 shows a perspective view of a clip for retrofitting
existing pumps of use with an occluder of the present
invention;
[0047] FIG. 11 shows a side cross-sectional view of a pair of
occluders and infusion line which form a pair of valves, and a
force applicator to form a linear peristaltic pump;
[0048] FIG. 12A shows a front view of an enteral feeding pump of
the prior art with an occludes in accordance with the present
invention disposed therein; and
[0049] FIG. 12B shows a close-up, cross-sectional view of the
occluder, infusion set and a portion of the pump to demonstrate
opening of a fluid flow pathway around the occluder.
DETAILED DESCRIPTION
[0050] Reference will now be made to the drawings in which the
various elements of the present invention will be given numeral
designations and in which the invention will be discussed so as to
enable one skilled in the art to make and use the invention. It is
to be understood that the following description is only exemplary
of the principles of the present invention, and should not be
viewed as narrowing the pending claims.
[0051] Referring to FIG. 1, there is shown a perspective view of an
infusion set 10 and related structures in accordance with the
teachings of the prior art. Disposed at one end 10a of the infusion
set 10 is a bag 14 for holding parenteral or enteral solutions.
Typically, the bag 14 is supported by a stand 18 which holds the
bag approximately 6 feet off the floor.
[0052] The opposing end 10b of the infusion set 10 is connected to
a patient (not shown). In a parenteral use, the end of the infusion
set 10 would have a needle attached thereto which extends into the
patient's venous system. In a enteral use, the end 10b would
typically have a fitting which attached to a balloon catheter (not
shown) mounted in a stoma in the patient's stomach. The end may
also be connected to a nasoenteric feeding tube.
[0053] Solution flows under gravity from the upper end 10a of the
infusion set 10 to the lower end 10b. The pressure on the fluid is
0.433 psi per foot. Thus, if the bag 14 is disposed five feet
higher than the patient, the pressure at the lower end 10b of the
infusion set 10 is 2.165 psi. From the extreme height of 8 feet to
the floor, the solution in the infusion set 10 can reach
approximately 3.5 psi.
[0054] To control the flow of solution through the infusion set 10,
the infusion set is typically mounted through a flow control
portion of a pump 22. The pump 22 selectively allows a metered
amount of solution to pass distally (downstream) from the pump.
This can be accomplished in multiple ways. For example, many
enteral feeding pumps are peristaltic pumps which have a rotor
which engages the infusion set 10 with a plurality rollers. Each
partial rotation of the rotor allows a predetermined dose to pass
to the patient. By controlling the rate at which the rotor turns,
the pump can provide highly accurate doses of the solution.
[0055] Other pumps known in the art control solution flow through
the infusion set 10 by a plurality of fingers which engage the
infusion set. By controlling the position and frequency of the
engagement of the fingers against the infusion set 10, a highly
accurate dose can be provided to the patient.
[0056] While the pump 22 controls the solution flow through the
infusion set 10 when the infusion set is properly loaded, failure
to load the infusion set properly in the pump quickly develops a
free flow condition in which the solution flows uncontrolled
through the infusion set. To prevent free flow, a clamp 26 is
disposed along the infusion set 10. Typically, the clamp 26 is
disposed above the pump 22. On common type of clamp 26 is a roller
clamp which allows some control over the presence of flow and flow
volume through the infusion set 10. Other clamps simply provide
on/off control.
[0057] While the infusion set 22 should be mounted in the pump 22
prior to or immediately after opening the clamp, this is not always
done. There are many situations in hospital or nursing home setting
in which the nurse or physician is called away or otherwise
distracted prior to proper placement of the infusion set 10. The
result is that the solution in the bag 18 flows uncontrolled into
the patient.
[0058] In many situations, the free flow of the solution will cause
no real threat to the patient. In some situations, however, free
flow can cause serious injury on even death to the patient. For
example, a critically ill patient may suffer severe shock if a
large amount of solution were to suddenly flow into his or her
body. Likewise, a patient receiving heavily medicated solution may
be seriously injured if a solution that was designed to be
delivered over a number of hours were delivered in a few
minutes.
[0059] To resolve such concerns, pinch clips may be disposed on the
infusion set 10. The pinch clip automatically closes the infusion
set unless it is properly mounted in the infusion set 10. An
example of such a pinch clip is disclosed in U.S. Pat. No.
5,810,323.
[0060] While such occluders are a significant advantage over the
possibility of free flow, they are relatively expensive to make.
While such an occluder may only cost ten to twenty cents, using a
new occluder with every infusion set adds a proportionally
significant amount to the cost of an infusion set. Thus, there is a
need to find an apparatus and method for preventing free flow in an
infusion set which is reliable and which is less expensive than the
prior art.
[0061] Turning now to FIG. 2A, there is shown a fragmented,
cross-sectional of an infusion set, generally indicated at 100,
with a stop or occluder 104 disposed therein. The infusion set 100
is formed by an elongate tube 108 made of a flexible, resilient
material such as silicone rubber, latex polyurethane, neoprene or
numerous similar medical grade materials. (In light of the present
disclosure, those skilled in the art will appreciate that the
present invention may be used in nonmedical contexts as well. In
such situations, the tube made be made of materials which are not
medical grade.)
[0062] The occluder 104 has an exterior diameter which is slightly
larger than the interior diameter of the tube forming the infusion
set 100. This causes a portion 108a of the tube to stretch slightly
as is passes over the occluder 104.
[0063] The occluder 104 prevents flow through the infusion set 100
based on gravity. Thus, the size of the occluder 104 will depend on
the material used to form the infusion set. In a presently
preferred embodiment, the infusion set 100 is formed from a tube
made of silicone rubber. The tube has a wall thickness of
approximately 0.038 inches and an inner diameter of approximately
0.130 inches. The occluder 104 is preferably formed out of a
plastic (e.g. acrylic (PMMA), polycarbonate, etc.) or a stainless
steel ball bearing having an outer diameter of 0.141 inches.
[0064] Because the occluder 104 is larger than the interior
diameter of the infusion set 100, solution which is under only the
force of gravity will back-up behind the occluder and not pass. To
prevent the occluder 104 from gradually working its way downstream,
a projection 112 can be formed in the infusion set 100 or, as
explained in detail below, the occluder may be fastened to a
connector or some other stationary structure.
[0065] Because the infusion set 100 is formed by an elongate,
resilient tube 108, increases in pressure will cause the interior
diameter of the tube to expand. When the tube 108 expands
sufficiently, the portion 108a of the tube which passes over the
occluder 104 allows the solution to flow around the occluder and
into the distal part 100b of the infusion set 100 as shown in FIG.
2B.
[0066] Preferably, the occluder 104 and infusion set 100 are
selected so that up to 4 psi can be maintained upstream of the
occluder, i.e. in the proximal portion of the infusion set, before
the portion 108a of the elongate tube 108 extending over the
occluder will expand sufficiently to allow any clinically
significant amount of solution to pass.
[0067] While solution hanging in the bag 18 may develop 2 to 3 psi
due to gravity, it will not have enough pressure to pass by the
occluder 104 without application of some external force. In
contrast, an enteral feeding pump or other type of pump will
typically generate between 5 and 10 psi. When the solution is
pressurized to 5 to 10 psi by the pump, the solution is under
sufficient pressure to go around the occluder 104 for delivery to
the patient. In other words, if the infusion set 100 is not
properly mounted in the pump so that the pump will generate a
higher pressure in the proximal part 10a of the infusion set, the
occluder 104 inhibits flow to the patient. Thus, there can be no
free flow while accommodating flow of solution to the patient when
the infusion set 100 is properly mounted in the pump.
[0068] Turning now to FIG. 2C, there is shown a fragmented, side
cross-sectional view of an alternate configuration of an infusion
set, generally indicated at 130, and the occluder 104. As with the
previous embodiment, the occluder 130 is formed by a small sphere,
typically formed of a biologically inert plastic or stainless
steel. The infusion set 130 is formed of a first tube 134 and a
second tube 138. The first tube 134 is formed of a resilient
polymer or silicone so that the tube may expand with pressure. The
second tube 138 is typically slightly smaller than the first tube
134 so that the distal end 134a of the first tube can be attached
to the exterior of the proximal end 138a of the second tube.
[0069] To ensure that the occluder 104 does not advance distally
into the second tube 138, the second tube 138 is preferably formed
from a material which is semi-resilient or nonresilient and
therefore will not accommodate advancement of the occluder 104. To
prevent the proximal end 138a of the second tube 138 from forming a
seal with the occluder 104, the proximal end preferably has one or
more indentations 142 or contours formed therein. The indentations
142 or contours ensure that liquid will be able to flow around the
occluder 104 even if the occluder is pressed firmly against the
proximal end 138a of the second tube 138.
[0070] When pressures less than about 4 psi are disposed proximally
from the occluder 104, the first tube 134 engages the occluder and
prevents liquid from flowing down stream. Once the pressure on the
proximal side of the occluder 104 exceeds approximately 4 psi, the
distal end 134a of the first tube 134 distends and allows liquid to
flow by in the manner demonstrated by arrows 146. Once the pressure
subsides, the first tube 134 returns to its original size and
liquid flow terminates until the pressure again is raised above the
threshold.
[0071] In use, the infusion set 130 and occluder 104 prevent free
flow unless the infusion set is placed in engagement with a pump
that can generate sufficient psi to compel flow around the
occluder. Once past the occluder 104, the pressure of the liquid
quickly falls and there is no danger to the patient.
[0072] Turning now to FIG. 3A, there is shown a fragmented,
cross-sectional view of another embodiment of principle of the
present invention. An infusion set 160 has a proximal portion 160a
and a distal portion 160b. Disposed between, the proximal portion
160a and the distal portion 160b is an occluder or stop 164. The
stop 164 is disposed in the infusion set 160 to selectively prevent
flow from the proximal portion 60a to the distal portion 160b.
[0073] The stop 164 includes a proximal end 164a and a distal end
164b. Beginning at the proximal end 164 is a channel 170. As shown
in FIG. 3A, the channel has a proximal portion 170a and two distal
portions 170b which are in fluid communication with the proximal
portion. While the proximal portion 170a is disposed in continuous
communication with the interior of the proximal portion 160a, each
of the distal portions 170b of the stop 164 are typically disposed
in communication with the is sidewall of the infusion set 160. The
sidewall of the infusion set 160 normally prevents fluid flow out
of the distal portions 170b of the channel 170.
[0074] Preferably the sidewall will have sufficient resistance to
expansion that a pressure of about 4 psi could placed in the
channel 170 without causing the infusion set 160 to radially
distend. Thus, if the pressure in the proximal portion 160a of the
infusion set 160 is below about 4 psi, the liquid will not flow
through the stop 164.
[0075] As shown in FIG. 3A, the stop 164 is relatively long. To
maintain itself in place, the stop 164 frictionally engages the
sidewall defining the infusion set 160. By providing a stop 164
which is long, greater surface area is provided to engage the
sidewall and prevent the stop 164 from being slowly moved
downstream.
[0076] Turning now to FIG. 3B, there is shown a fragmented, side
cross-sectional view of an infusion set, generally indicated at
180. The infusion set 180 includes a proximal (upstream) end 180a
and a distal (downstream) end 180b which are separated by an
occluder or stop 184. The stop 184 is similar to the stop 164 shown
in FIG. 3A in that it has a channel 190 with a proximal portion
190a and a pair of distal portions 190b.
[0077] Rather than relying on an elongate body and frictional
engagement with the sidewall of the infusion set 180, the stop 184
has at least one projection 194 which extends outwardly from the
stop to engage the sidewall of the infusion set and prevent
advancement. Preferably, the projection 194 is formed by an annular
projection, or a plurality of spaced projections extending radially
outwardly from the stop 184.
[0078] Turning now to FIG. 3C there is shown a cross-sectional view
of the infusion set 180 and stop 184 of FIG. 3B. As the pressure in
the proximal portion 180a of the infusion set 180 increases to
greater than about 4 psi, the infusion set will distend radially.
This allows liquid contained in the proximal portion 180a of the
infusion set 180 to flow into the proximal portion 190a of the
channel 190, out the distal portions 190b of the channel and into
the distal portion 180b of the infusion set. Once the pressure
drops below about 4 psi, the infusion set 180 will retract and the
flow in the channel 190 will be terminated as the sidewall of the
infusion set covers the distal portions 190b of the channel
190.
[0079] In such a manner, the embodiments shown in FIGS. 3A through
3C prevent free flow by preventing liquid flow under 4 psi. Once
the infusion set 180 is properly mounted in the pump, the increased
pressure created by rotation of the rotor (or other pressure
source) overcomes the restriction to flow imposed by the stop 184.
When combined with the control provided by the various types of
infusion pumps, the occluder or stop 164 or 184 enables a
predetermined amount of liquid to flow through infusion set 160 or
180 while preventing the dangers of free flow conditions.
[0080] FIG. 3D shows a side cross-sectional view of yet another
embodiment of an infusion set, generally indicated at 200, having
an occluder or stop 204 disposed therein. The infusion set 200
includes a proximal portion formed by a first tube 208 and a distal
portion formed by a second tube 212. The proximal end 212a of the
second tube 212 is mounted about the exterior of the distal end
208a of the first tube 208.
[0081] Disposed at the distal end 208a of the first tube 208 and
the proximal end 212a of the second tube 212 is the stop 204. The
stop 204 has a channel 216 extending from a proximal end 204 of the
stop to a radially lateral position adjacent the distal end 204b of
the stop. Thus, the channel is in fluid communication with liquid
in the first tube 208, but is normally isolated from the interior
of the second tube 212.
[0082] When pressures in the first tube exceed about 4 psi, the
proximal end 212a of the second tube 212 radially expands, thereby
opening the distal end of the channel 216 and allowing liquid to
flow into the distal portion of the infusion set formed by the
second tube 212.
[0083] By positioning the stop 204 at the ends of two tube
segments, the stop can be adhesively attached to either of the
tubes to prevent distal movement of the stop. This can be
accomplished without interfering with the ability of the stop to
prevent flow below about 4 psi, while allowing pressures above
about 4 psi cause liquid to pass through the infusion set.
[0084] While the embodiments of FIGS. 3A through 3D show
embodiments in Which the proximal end of the channel is in
continuous communication with the upstream flow and the distal end
of the channel is normally closed, the stop 164, 184 or 204 could
be rotated so that the proximal or upstream portion of the channel
is normally closed by the sidewall of the infusion set 160, 180 or
200 and the distal portion of the channel is always in
communication with the distal portion of the infusion set.
[0085] FIG. 3E shows yet another embodiment of an infusion set,
generally indicated at 230, and an occluder 234. The occluder 234
is disposed in the infusion set 230 so as to divide the infusion
set 230 into a proximal, upstream portion 230a and a distal,
downstream portion 230b.
[0086] The occluder 234 has a channel 238 which extends from a
proximal end 234a of the occluder to the distal end 238b so as to
form a passageway through which an infusion liquid, such as enteral
feeding solution, may pass. A wall 242 is disposed along the
channel 238 to selectively prevent flow through the channel. In
accordance with the principles of the present invention, the wall
242 is pivotably attached to the occluder 234 in such a manner that
the wall will not move to allow liquid flow through the channel
until the proximal, upstream pressure exceeds 4 psi. (While
described as requiring a threshold upstream pressure, in light of
the present disclosure those skilled in the art will appreciate
that the wall will move based on a pressure differential between
the two proximal and distal portions of the infusion set. Thus, the
same effect could be generated by developing a vacuum downstream
from the occluder 234).
[0087] Once the desired pressure threshold has been reached, the
wall 242 will pivot and open the channel 238 to flow. Once the
pressure drops, the wall 242 will pivot closed in accordance with
one method of use. In accordance with another method of use,
however, the wall 242 can have a score 246 formed therein. The wall
242 is designed to remain occluding the infusion set 230 until the
pressure threshold is exceeded. Once deflected out of the way, the
wall may not return to its original position even after the
pressure drop. Because the pressure increase necessary to move the
wall 242 is generated by the pump (not shown), the infusion set 230
must have been properly loaded in the pump for the wall to open.
When the infusion set 230 is properly loaded in the pump, the pump
will prevent free flow. Thus, if the infusion set 230 is properly
loaded in the pump, the occluder does not need to continue to
prevent free flow.
[0088] Turning now to FIGS. 4A and 4B, there are shown fragmented,
side cross-sectional views of yet another embodiment of the present
invention. An infusion set, generally indicated at 250 has an
occluder 254 in the form of a duckbill valve formed therein to
divide the infusion set 250 into a proximal, upstream portion 250a
and a distal, downstream portion 250b. The occluder 254 is formed
of two vanes 258a and 258b which are biased into engagement with
one another.
[0089] When the pressure in the proximal portion 250a of the
infusion set 250 is less than about 4 psi, the biasing of the vanes
258a and 258b keep them in contact as shown in FIG. 4A. Once the
pressure in the proximal portion 250a exceeds about 4 psi, the
pressure forces the valves 258a and 258b away from each other,
thereby allowing an infusion liquid to flow through the occluder
254 and into the distal portion 250b of the infusion set 250 as
shown in FIG. 4B. In order for the occluder 254 to work in such a
manner, it is preferable for the vanes 258a and 258b to extend
distally as they engage one another. However, the occluder 254
could be made so that the vanes extend proximally and then buckle
once the threshold pressure has been passed.
[0090] The occluder 254 is shown as being molded integrally with
the infusion set 250. Such a configuration prevents any concern as
to whether the occluder 254 may move during use. However, it is
feasible to also form such an occluder 254 as a separate unit and
then position it within the infusion set 250. The occluder 254
could be held in place with adhesives or merely a friction fit.
[0091] Turning now to FIG. 5A there is shown a fragmented, side
cross-sectional view of an infusion set, generally indicated at
300, with an occluder 304 disposed therein. Similar to the
embodiment shown in FIG. 2A, the infusion set 300 is made of
conventional silicone tubing or some other resilient or
semi-resilient material, such as latex, polyurethane, etc.
[0092] FIG. 5B shows a cross-sectional view of the infusion set 300
and occluder 304 taken along the plane A-A in FIG. 5A. As shown,
the tube defining the infusion set 300 forms a seal around the
occluder 304 and prevents liquid from passing between the occluder
and the tube forming the infusion set.
[0093] Turning now to FIG. 5C, there is shown a side
cross-sectional view of the infusion set 300 and the occluder 304.
Disposed behind the infusion set 300 at the location of the
occluder 304 is a wall 308. As will be discussed in additional
detail below, the wall 308, the occluder 304 and the infusion set
300 form a compression valve for selectively allowing liquid to
flow through the infusion set.
[0094] FIG. 5D shows a cross-sectional view of the infusion set 300
and the occluder 304 taken along the plane B-B in FIG. 5C. The
infusion set 300 and occluder 304 have been mounted between
opposing walls 308 which are spaced apart a distance slightly
smaller than the outer diameter of the infusion set. As the
infusion set 300 is placed between the opposing walls 308, the
sides of the tubing forming the infusion set are compressed and
held against the occluder 304. This compression also causes the top
and bottom 300a and 300b portions of the tube to extend radially
outwardly from the occluder 304, thereby opening a flow path 312
above and below the occluder. The flow paths 312 enable liquid in
the infusion set 300 to flow around the occluder 304 and to flow to
the patient.
[0095] In the event that the infusion set 300 and occluder 304 are
pulled out from between the opposing walls 308, the tube forming
the infusion set 300 will return to the position shown in FIGS. 5A
and 5B, thereby terminating flow through the infusion set. Thus,
the configuration shown in FIGS. 5A through 5D prevents free flow
of infusion liquids through the infusion set 300 so long as the
infusion set and occluder 304 are properly mounted between the
walls 308 (or some analogous engagement surfaces). The infusion set
300 and occluder 304 are typically positioned between the walls 308
as the infusion set is being loaded into the pump (not shown). Once
properly loaded, the pump controls flow through the infusion set
300 and prevents free flow.
[0096] Turning now to FIG. 5E, there is shown a perspective view of
a housing of an enteral feeding pump, generally indicated at 330,
made in accordance with one aspect of the present invention. The
housing 330 includes a pair of channels 340 and 344 for holding a
portion of an infusion set tube, such as those discussed with
respect to FIGS. 3A through 5D. In use, the tube is placed in one
channel 340, wrapped about a motor unit (not shown) which is placed
in the opening 350, and then positioned in the second channel 344.
If a conventional infusion set is not properly wrapped about the
motor unit (or properly installed in other types of pumps) and
placed in the channels 340 and 344, a free-flow condition may
develop. However, the present invention prevents such a situation
from developing.
[0097] As shown in FIG. 5E in broken lines, the infusion set 354 is
mounted in the first and second channels 340 and 344. At least a
portion 340a of the channel 340 is sufficiently narrow to form
walls, similar to walls 308 in FIGS. 5A through 5D, which compress
the sides of the tube forming the infusion set 354, thereby
creating a flow path around the occluder (not shown) in the
infusion set. If desired, the entire length of the walls 360 which
form the channel 340 could be sufficiently close together to
compress the infusion set 354 and thereby open flow.
[0098] FIG. 5E also shows a cover 370 which is connected to the
housing 330. The cover 370 is pivotable with respect to the housing
330 and includes a catch 374 which engages a groove 380 on the
housing. When the cover 370 is closed and the catch 374 engaged in
the groove 380, the infusion set 354 is securely held in the
housing 330 and it is unlikely that the infusion set may be pulled
from the pump.
[0099] Rather than having the walls 360 of the channel 344 compress
the sides of the infusion set 354 to form a compression valve with
the sides of the infusion set 354, a projection 384 can be mounted
on the cover 370 so that it is in alignment with the infusion set.
When the cover closes, the projection 384 applies a downward force
on the infusion set 354 thereby forming an open compression valve
with the flow channels being disposed in horizontal alignment,
rather than vertical alignment as shown in FIG. 5D. Thus, liquid
flowing through the infusion set 354 passes around the sides of the
occluder, as opposed to above and below the occluder.
[0100] It will be appreciated in light of the present disclosure,
that when a projection is used to engage the occluder, the occluder
need not be held in a channel. Rather, the infusion set 354 must
only be engaged on generally opposing sides so as to open at least
one flow path around the occluder, or sufficient pressure must be
exerted to cause the infusion set to expand and open a flow
path.
[0101] As long as the catch 374 on the cover 370 engages the groove
380 on the housing 330, or the projection 384 is maintained in
engagement with the infusion set 354 at the location of the
occluder, the compression valve will remain open. If the cover 370
is opened, the force holding the compression valve open is gone and
the infusion set 354 will retract into the closed position shown in
FIGS. 5A and 5B, thereby preventing free flow through the infusion
set 354.
[0102] Turning now to FIGS. 6A and 6B, there is shown yet another
embodiment of the present invention. The infusion set, generally
indicated at 400, has an occluder 404 disposed therein. The
occluder 404 may be molded in the infusion set 400, or may be
constructed separately and inserted.
[0103] The occluder 404 is formed by a first vane 408a and second
vane 408b which form a duck-bill valve. The vanes 408a and 408b are
disposed so that they extend proximally (i.e. upstream). As shown
in FIG. 6A, the vanes 408a and 408b normally engage one other to
occlude flow from a proximal portion 400a of the infusion set 400
to a distal portion 400b of the infusion set.
[0104] When pressure is applied to the tubing which forms the
infusion set 400, the vanes 408a and 408b move away from each other
sufficiently to allow fluid flow through the infusion set. Thus, in
FIG. 6, a compression valve is formed by sliding the infusion set
400 between two walls 412 of engagement surfaces so that the vanes
408a and 408b are held apart, or by forcefully engaging the
infusion set with a projection or other structure associated with a
door, etc. As long as the infusion set 400 remains between the
walls 412, projections, etc., fluid flow is enabled. If the portion
of the infusion set 400 which contains the occluder 404 is pulled
from the walls 412 or projections, the occluder will return to the
closed position wherein it prevents free flow.
[0105] Preferably, the infusion set 400 and occluder 404 will be
used in a housing, such as that shown in FIG. 5E. When the infusion
set 400 is mounted in a channel defined by restricting sidewalls or
when a cover with an aligned projection is closed, flow is enabled
through the infusion set. If the infusion set 400 is pulled out of
the housing, the occluder 404 will automatically close--thereby
preventing free flow through the infusion set.
[0106] The various embodiments disclosed in accordance with the
present invention provide a marked improvement over clamps and
other types of external occluders which are commonly used to
control fluid flow. The embodiments provide assurance against free
flow, are generally easier to handle and are much more cost
effective than the external occluders of the prior art.
[0107] In addition to being usable with housings and other fixed
structures which cause the valve to open, the majority of
configurations discussed above can also be manually opened by
simply squeezing the infusion set adjacent the occluder to open a
pathway around the occluder. The availability to manually open the
occluder/infusion set is desirable, as it facilitates priming of
the infusion set with the liquid being infused. Unlike many of the
occluders of the prior art however, simply releasing the infusion
set adjacent the occluder is all that is required to terminate
flow.
[0108] Turning now to FIG. 7, there is shown another configuration
of an infusion set, generally indicated at 400, and an occluder,
404 made in accordance with the principles of the present
invention. The infusion set 400 is formed by an elongate tube 108
made of a flexible, resilient material such as silicone rubber,
latex, polyurethane, neoprene or numerous similar materials.
Typically, the elongate tube has an inner diameter of approximately
0.130 inches.
[0109] The occluder 404 has an exterior diameter which is slightly
larger than the interior diameter of the tube forming the infusion
set 400, typically about 0.141 inches. This causes a portion 408a
of the tube to stretch slightly as is passes over the occluder
404.
[0110] The occluder 404 prevents flow through the infusion set 400
based on gravity. Thus, the exact size of the occluder 404 will
depend on the material used to form the infusion set 460. In a
presently preferred embodiment, the infusion set 400 is formed from
a tube made of silicone rubber, and the occluder 404 is formed from
a plastic (e.g. acrylic (PMMA), polycarbonate, etc.) cylinder
having an outer diameter of 0.141 inches and a length of about
0.282 inches.
[0111] Because the occluder 404 is larger than the interior
diameter of the infusion set 400, solution which is under only the
force of gravity will back-up behind the occluder and not pass.
Once sufficient pressure is present--e.g. pressure produced by a
pump--the walls of the infusion set will expand to allow fluid flow
past the occluder 400 as discussed with respect to FIG. 2A,
etc.
[0112] While the embodiment shown in FIG. 2A is spherical and the
embodiment shown in FIG. 7 is cylindrical, those skilled in the art
will appreciate that numerous other embodiments could be used. For
example, the dashed line 412 illustrates an occluder which is
bullet shaped occluders can also be egg shaped, or any other shape
which provides a stop to fluid flow until a predetermined pressure
threshold has been reached. It will also be appreciated that the
occluder 404 need not have a consistent diameter. By having a
portion of the occluder 404 extend radially a greater distance than
other parts, a portion of the occluder will always engage the wall
of the infusion set 400, thereby reducing the ability of the
occluder to move within the infusion set.
[0113] Turning now to FIG. 8, there is shown still another
configuration of an infusion set 420 and occluder 424 made in
accordance with the principles of the present invention. The
infusion set 420 is formed from an elongate tube 428 which has a
first portion 432 and a second portion 436 which are connected
together by a connector 440. The occluder 424 is attached to the
connector 440 by a tether 442 to prevent the occluder from
advancing along the second portion 436 of the elongate tube
428.
[0114] When sufficient pressure is present in a proximal, upstream
portion 428a of the elongate tube 428, the second portion 432 will
expand sufficiently to allow fluid flow past the occluder 424 and
into the distal, downstream portion 428b of the infusion set 420.
One advantage of using the connector is that the first portion 428a
of the elongate tube 428 need not be formed of a material which is
resilient, or may use a material which does not expand or contract
consistently. In other words, less expensive tubing materials may
be used for most of the infusion set 420 without interfering with
the interaction between the infusion set and the occluder 424.
[0115] While shown in FIG. 8 as being generally spherical, it
should be appreciated that, in accordance with the present
invention, the occluder 424 could be a variety of shapes.
Additionally, the a single tether 442 or a plurality of tethers
could be used to hold the occluder 424 to the connector 440.
[0116] FIG. 8A shows a cross-sectional view of another
configuration of an infusion set 420, and an occluder 444. Unlike
the spherical occluder 424 of FIG. 8, the occluder 444 of FIG. 8A
is disk shaped. To prevent the occluder 444 from rotating in
response to fluid pressure and inadvertently opening a fluid flow
path, a plurality of tethers 442 are used to secure the disk to the
connector 440.
[0117] When pressure in the infusion set 420 is sufficient, the
tube 428 will expand and allow fluid flow past the occluder 444.
Once the pressure drops below a predetermined threshold, the tube
428 will again engage the occluder 444 and terminate flow.
[0118] FIG. 8B shows a cross-sectional view of still yet another
configuration of an occluder, 446, made in accordance with the
principles of the present invention. The infusion set 420 and
related portions are the same as in FIGS. 8 and 8A and are numbered
accordingly.
[0119] The connector 440 is attached by one or more tethers 442 to
the occluder 446 to prevent the occluder from moving down stream.
The tethers 442 can also be used to keep the occluder 446 in a
desired orientation. When sufficient pressure is present, the tube
436 expands to allow fluid flow past the occluder 446.
[0120] FIG. 9 shows yet another aspect of the invention wherein the
infusion set 450 and occluder 454 forms part of a liquid control
valve, generally indicated at 460. In accordance with the
embodiments discussed above, and particularly the discussion
surrounding 5A through 5E, the occluder 454 normally prevents fluid
flow through the infusion set. However, squeezing the infusion set
on an opposing sides of the infusion set sidewall 450a caused other
portions of the sidewall to extend away from the occluder 454--as
demonstrated in FIGS. 5C and 5D.
[0121] Disposed adjacent to the infusion set 450 and occluder 454
are a pair of engagement members 464 which are in communication
with an actuator 468, such as a motor. The communication can be
electronic, mechanical or pneumatic, so long as the actuator 468 is
able to control movement of one or more of the engagement members
464.
[0122] When the engagement members are actuated, they apply and
inward force to the infusion set 450 at the location of the
occluder 454 to open a passage way around the occluder and thereby
enable fluid flow through the infusion set. When the engagement
members 464 are adjusted to no longer apply sufficient force to the
infusion set 450, the infusion set again surrounds the occluder 454
and prevents fluid flow.
[0123] By selectively actuating the engagement members 464, the
infusion set 450 and occluder 454 a valve is formed for controlling
fluid flow. By applying a pressure sensor or other type of sensor,
the valve can be used to regulate flow and flow through the valve
can be determined.
[0124] Turning now to FIG. 10, there is shown a perspective view of
a clip, generally indicated at 480, for opening flow between an
occluder and infusion set. Those skilled in the art will appreciate
that there are a number of enteral and parenteral pumps in the
market which use various types of occluders which suffer from the
problems identified in the background section. To eliminate these
concerns, the clip 480 is configured for retrofitting an existing
pump for use with an occluder/infusion set made in accordance with
the principles of the present invention. (Of course, with some
existing pumps, the occluder and infusion set may be configured to
nest in the pump in such a manner that retrofitting is not
necessary.)
[0125] The clip 480 includes a base 484 which is provided for
attachment to the housing of a conventional fluid pump. Typically,
the base 484 will have an adhesive disposed thereon. If desired,
the adhesive may be selected from removable adhesives, such as
those known to those skilled in the art, so that the clip 480 can
be removed from the pump when an infusion set containing an
occluder (such as that represented by the dashed lines 488) is not
being used with the pump.
[0126] Extending from the base 484 is a fitting 490 having channel
492 formed therein. The channel 492 is preferably formed with an
open end and extends into the clip 480. As the infusion set,
represented in shadow at 488, is inserted into the channel 492,
walls 494 defining the channel compress the infusion set 488
against the occluder (shown as dashed lines 498) to open a pair of
flow channels between the occluder and the infusion set as shown in
FIGS. 5A through 5D.
[0127] As long as the infusion set 488 and occluder 498 remain
securely held between the walls 494 defining the channel 492, fluid
flow is enabled between the occluder and the infusion set. If the
infusion set 488 is pulled from the channel 492 or is never
properly placed in the channel, flow through the infusion set is
prevented. Thus, the risk of free flow developing within the system
is significantly reduced. Of course, the risk of free flow can
virtually be eliminated by placing the clip 480 on the pump in such
a manner that the infusion set 488 must be properly loaded in the
pump in order to fit within the channel 492.
[0128] FIG. 11 shows a side cross-sectional view of yet another
embodiment of the present invention which forms an in-line pump,
generally indicated at 500. As shown in FIG. 11, a pair of
occluders 504 and 508 are disposed in an infusion line 512. Each of
the occluders 504 and 508 is disposed adjacent an actuator 514 and
518, respectively. The actuators 514 and 518 are configured to
selectively apply pressure to the infusion line 512 to selectively
open flow channels between the infusion line and the occluder 504
or 508 with which each is associated.
[0129] In use, liquid in the infusion line 512 will be held in a
proximal portion 512a which is upstream from the first occluder
504. The first occluder 504 prevents the liquid from flowing down
stream until a drive mechanism 522 causes the first actuator 514 to
apply force to the infusion line 512 adjacent the first occluder.
Applying force to the infusion line 512 causes a channel to open
between the first occluder 504 and the infusion line, thereby
allowing fluid flow into a middle portion 512b of the infusion
line.
[0130] Once the middle portion 512b of the infusion line 512 has
had adequate time to fill with liquid, the actuator 514 is adjusted
so that it no longer applies sufficient force to the infusion line
to enable fluid flow around the occluder 504.
[0131] The liquid in the middle portion 512b of the infusion line
512 is then isolated from the liquid in the proximal portion
512a.
[0132] The liquid in the middle portion 512b of the infusion line
512 is prevented from flowing distally or downstream by the second
occluder 508 which defines the distal end of the middle portion.
However, once the drive mechanism 522 is actuated to move the
actuator 518 into forceful contact with the infusion line 512
adjacent the occluder 508, one or more channels are formed between
the occluder and the infusion line. The channel(s) opened by the
actuator 518 squeezing the infusion line 512 form a flow path
allowing the liquid contained in the middle portion 512b to flow
into a distal, downstream portion 512c. Since no occluder or other
stop is typically disposed distally from the second occluder 508,
the liquid flowing into the distal portion 512c is delivered to the
patient.
[0133] By selectively controlling the application of force by the
first actuator 514 on the infusion line 512 and first occluder 504
and the application of force by the second actuator on the infusion
line and second occluder 508, a valve, generally indicated at 526,
is formed which permits a predetermined amount of flow to pass with
each series of actuations.
[0134] In a more preferred embodiment, the valve also includes a
force applicator 530, such as a plunger, roller or similar device,
disposed in communication with the middle portion 512b of the
infusion line 512. The force applicator 530 applies a compressive
force to the middle portion 512b of the infusion line 512 to force
the liquid contained in the middle portion 512b to flow into the
distal portion 512c of the infusion line 512 and on to the patient.
The force applicator 530 ensures that liquid will not simply remain
in the middle portion 512b when the second actuator 518 causes a
flow path to be formed between the second occluder 508 and the
infusion line 512.
[0135] While applying a compressive force to the middle portion
512b of the infusion line 512 helps to force the liquid in the
middle portion to flow downstream, it also serves to assist flow
into the middle portion. Once a compressive force is no longer
applied to the middle portion 512b, the resilient material forming
the infusion line will attempt to return to its original, tubular
configuration. By closing the flow path between the second occluder
508 and the infusion line 512 before releasing force applicator
530, a vacuum is formed within the middle portion 512b. Once the
actuator 514 opens a flow path between the first occluder 504 and
the infusion line 512, the vacuum in the middle portion 512b will
draw liquid into the middle portion 512b as the infusion line
returns to its original configuration.
[0136] In each cycle of the valve 526, the first actuator 514 will
open a flow channel between the first occluder 504 and the infusion
line 512 to fill the middle portion 512b with liquid. The first
actuator 514 will then allow the flow channel to close. The second
actuator 518 will then open a flow channel between the second
actuator 508 and the infusion line 512 and the force applicator 530
will apply pressure to the infusion line forming the middle portion
512b so that the liquid in the middle portion will flow into the
distal portion 512c and to the patient. The second actuator 518
will then allow the flow channel between the second occluder 508
and the infusion line 512 to close. The process will then be
repeated.
[0137] By controlling the interior diameter of the infusion line
512, the distance between the first occluder 504 and the second
occluder 508, and the movement/size of the force applicator 530,
one can obtain a predetermined amount of liquid flow with each
cycling of the valve 526. By controlling the number of cycles in a
predetermined period of time, the operator is able to provide a
highly accurate rate of flow for the solution passing through the
valve 526. Furthermore, because a rotor is not needed to control
flow rate, the valve 526 can be used to make an in-line peristaltic
pump which is significantly thinner than conventional peristaltic
pumps while maintaining the same accuracy.
[0138] While FIG. 11 shows two actuators, those skilled in the art
will understand, in light of the present invention, that one of the
occluders could be configured to allow fluid flow responsive to
force if configured properly to prevent back flow. This could be
achieved, for example, by controlling the size of the
occluders.
[0139] Turning now to FIG. 12A, there is shown a perspective view
of a pump, generally indicated at 600, which is designed to control
fluid flow through an infusion set, generally indicated at 604, and
into the patient. The pump 600 includes a control panel 608 which
has a plurality of buttons 610 or other devices for controlling the
actuation of the pump. The pump 600 operates to deliver a
predetermined dose of enteral feeding solution to a patient by
rotation of a rotor 612.
[0140] The infusion set 604 is mounted on the pump so that a
resilient portion 604a of the infusion set wraps around the rotor
612. Each rotation or partial rotation of the rotor 612 causes a
predetermined amount of enteral feeding solution to be advanced
through the infusion set 604 and delivered to the patient.
[0141] In order to assure that the rotor 604 is providing the
proper amount of enteral feeding solution, a drip chamber 620 is
formed along the infusion set. An optical sensor 624 is disposed in
the enteral feeding pump 600 and monitors the drip rate of the
solution in the drip chamber 624. The drip rate of the solution is
used to calculate an actual delivery rate of the solution.
[0142] As with the prior art, a portion 604b of the infusion set
disposed distally from the rotor 612 is nested in a channel 630 in
the pump housing 600. In accordance with the present invention, the
portion 604b has an occluder 634 disposed therein. While the prior
art simply used the channel 630 to hold the infusion set 604 in
contact with the rotors, the inclusion of an occluder 634 provides
an improved measure of safety.
[0143] In the prior art, if either the portion 604b of the infusion
set 604 was not properly positioned in the channel 630, a free flow
condition could develop in which fluid flow through the infusion
set would be unchecked by the rotor 612. In the present invention,
flow through the infusion set 604 is not permitted until the
portion 604b with the occluder 634 is nested in the channel 630. If
the portion 604b of the infusion set 604 is not properly placed in
the channel 630 or is pulled from the channel, the occluder 630
will prevent free flow through the infusion set.
[0144] FIG. 12B shows a close-up, cross-sectional view of the
portion of the pump 600 having the channel 630 formed therein taken
along the line A-A. The channel 630 receives the infusion set 604
in such a manner that it compresses the tube 642 against the
occluder 634. This causes another portion of the tube 642 to extend
away from the occlude 634 and thereby open a fluid flow path
between the inner wall of the tube and the occluder.
[0145] As shown in FIG. 5D, compressing opposing sides of the
infusion set can open fluid flow channels both above and below the
occluder. In FIG. 12B, the tube 642 of the infusion set 604 is
pressed against one half of the occlude 634, thereby forming a
single fluid flow channel 646 on the opposing side. If the portion
604b of the infusion set 604 containing the occluder 634 is pulled
from the channel 630, the infusion set will engage the occluder
prevent fluid flow.
[0146] Thus there is disclosed an improved apparatus and method for
preventing free flow in an infusion line. The apparatus and method
can be used with infusion control pumps, such as enteral feeding
pumps or IV pumps, or as a replacement for such pumps. While the
present disclosure discloses embodiments which are currently
preferred, those skilled in the art will appreciate numerous
modifications which can be made without departing from the scope
and spirit of the present invention. For example, the relative size
of the infusion set and occluder could be changed by providing an
occluder which shrinks sufficiently under pressure to create fluid
flow passages. The appended claims are intended to cover such
modifications.
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