US20110004190A1 - Apparatus and method for preventing free flow in an infusion line - Google Patents

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. The occluder may also be configured to allow flow when the infusion set adjacent the occluder is moved sideways relative to the occluder or maintained at an angle relative to the occluder. When a pair of occluders are used in sequence, an in-line pump may be formed.

Description

RELATED APPLICATIONS
• The present application is a continuation-in-part of U.S. patent application Ser. No. 10/317,027, filed Dec. 11, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 09/836,850, filed Apr. 16, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09/569,332, filed May 11, 2000, U.S. Pat. No. 6,595,950.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to an apparatus and method for preventing free flow during enteral or parenteral administration of 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.
• 2. State of the Art
• 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. Various 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.
• 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.
• It is not uncommon, however, for emergencies or other distractions to prevent the medical personnel from properly loading the infusion set in the enteral feeding pump. A problem of anticipated flow may occur where an undesired amount of a solution is delivered to a patient. Unanticipated flow may involve unchecked flow, as may be known as free flow, or may simply involve greater than desired flow. Unanticipated flow may occur where there is an improperly loaded infusion set, etc. Thus, the present invention is directed towards preventing unanticipated flow through the infusion set, and is hereafter referred to as preventing “free-flow” for simplicity throughout the application. 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/or the patient's body is not physically strong enough to adjust to the large inflow of solution.
• 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.
• 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. Furthermore, there is a need for a device which prevents free-flow and which is inexpensive and easy to use.
SUMMARY OF THE INVENTION
• 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.
• It is another object of the present invention to provide an occluder which is simple to make and use.
• It is another object of the present invention to provide such an occluder which is relatively inexpensive.
• 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.
• It is still yet another aspect of the present invention to provide an occluder which functions as at least part of a valve to effectively control fluid flow through a conduit.
• One or more of 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, to selectively allow solutions to pass by the occluder which are pumped by an enteral feeding pump and the like. It will be appreciated that all embodiments shown or claimed need not accomplish each objective.
• 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 through the tube by limiting 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.
• 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.
• 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, the infusion set, and the pump effectively engages the infusion set to allow solution to flow therethrough.
• 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.
• 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 pump which delivers predetermined amounts of fluid to a patient.
• 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.
• In accordance with another aspect of the present invention, the occluder and infusion set may be disposed in the pump such that the tubing of the infusion set is held at an angle relative to the axis of the occluder. The tubing may be held at such an angle to modify the sealing characteristics of the occluder. In one embodiment, the pump is formed such that when the infusion set is loaded by wrapping the tubing around the pump rotor, the infusion set tubing is held at an angle relative to the occluder such that an opening is formed between the occluder and the infusion set. In another embodiment, the pump is designed such that an arm or protrusion associated with the pump is moved into a position whereby the arm pushes on the infusion set tubing near the occluder sufficient to form an opening between the occluder and the tubing.
BRIEF DESCRIPTION OF THE DRAWINGS
• 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:
• FIG. 1 shows an perspective view of an infusion set made in accordance with the prior art;
• 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;
• FIG. 2B shows a fragmented, side cross-sectional view similar to that ofFIG. 2A, wherein the occluder and infusion set are in an open configuration;
• 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;
• 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;
• 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;
• FIG. 3C shows a cross-sectional view of the occluder embodiment ofFIG. 3A with the occluder and infusion set being disposed in an open configuration;
• 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;
• 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;
• FIG. 4A shows fragmented, side cross-sectional view of another embodiment of an occluder and infusion set with the occluder in a closed configuration;
• FIG. 4B shows a cross-sectional view of the embodiment ofFIG. 4A in an open configuration;
• FIG. 5A shows a 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;
• FIG. 5B shows a cross-sectional view taken alongplane5A-5A ofFIG. 5A;
• 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;
• FIG. 5D shows a cross-sectional view taken along theplane5B-5B ofFIG. 5C;
• 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 inFIG. 5D;
• 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;
• FIG. 6B shows a view similar to that shown inFIG. 6A with the occluder held in an open position;
• FIG. 7 shows another configuration of an occluder made in accordance with the principles of the present invention;
• FIG. 8 shows yet another configuration of an occluder made in accordance with the principles of the present invention;
• FIG. 8A shows a cross-sectional view of another configuration of an occluder in accordance with the present invention;
• FIG. 8B shows a cross-sectional view of still yet another configuration of an occluder in accordance with the present invention;
• FIG. 9 shows yet another aspect of the invention wherein the occluder forms part of a liquid control valve;
• FIG. 10 shows a perspective view of a clip for retrofitting existing pumps of use with an occluder of the present invention;
• 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;
• FIG. 12A shows a front view of an enteral feeding pump of the prior art with an occluder in accordance with the present invention disposed therein;
• FIG. 12B shows a close-up, cross-sectional view of the occluder disposed in tubing of an infusion set and a portion of the pump to demonstrate opening of a fluid flow pathway around the occluder;
• FIG. 13A shows a side view of an alternate embodiment of an occluder made in accordance with the principles of the present invention;
• FIG. 13B shows a cross-sectional view of the occluder embodiment ofFIG. 13A taken along the line13A-13A;
• FIG. 13C shows an end view of the occluder ofFIGS. 13A and 13B;
• FIG. 13D shows a top view of an enteral feeding pump having an infusion set disposed therein, with an occluder positioned in the infusion set to prevent free-flow therethrough in accordance with the present invention;
• FIG. 13E shows a front view of another available enteral feeding pump having an infusion set disposed therein, with an occluder positioned in the infusion set to prevent free-flow therethrough in accordance with the present invention;
• FIG. 14A shows a perspective view of an alternate embodiment of an occluder made in accordance with the principles of the present invention;
• FIG. 14B shows a side view of the occluder ofFIG. 14;
• FIG. 14C an end view of the occluder ofFIG. 14;
• FIG. 15 shows a top view of yet another embodiment of an occluder made in accordance with the principles of the present invention;
• FIG. 15A shows a cross-sectional view of a portion of an infusion set with the occluder ofFIG. 15 disposed therein;
• FIG. 15B shows a top view of a stop of an occluder showing an alternate configuration for the stop relative to that shown inFIG. 15;
• FIG. 15C shows a top view of an alternate embodiment of an occluder stop;
• FIG. 15D shows a top view of another embodiment of an occluder stop;
• FIG. 15E shows a top view of yet another occluder stop made in accordance with the principles of the present invention;
• FIG. 15F shows a top view of still another stop of an occluder showing an alternate configuration for the stop relative to that shown inFIGS. 15 through 15E;
• FIG. 15G shows a top view of still another stop of an occluder in accordance with the principles of the present invention;
• FIG. 15H shows a cross-sectional view of a portion of an infusion set with the occluder ofFIG. 15 disposed therein;
• FIG. 16 shows a fragmented, cross-sectional view of an infusion set tube with an occluder disposed therein and a control mechanism to maintain the infusion set and occluder in an open configuration;
• FIG. 17 shows a front view of an enteral feeding pump having an infusion set disposed therein;
• FIG. 18 shows a fragmented cross-sectional view of an infusion set tube and occluder according to the present invention;
• FIG. 19 shows a fragmented cross-sectional view of an infusion set tube and occluder according to the present invention;
• FIG. 20 shows a top fragmented cross-sectional view of an infusion set tube, occluder, and pump rotor according to the present invention with the infusion set engaging the roller of a peristaltic pump;
• FIG. 21 shows a fragmented cross-sectional view of an infusion set tubing and occluder according to the present invention being acted on by a projection from an enteral feeding pump or the like;
• FIG. 22 shows a side view of an alternate embodiment of an occluder according to the present invention;
• FIG. 23 shows a fragmented cross-sectional view of an infusion set tubing and still another embodiment of an occluder according to the present invention;
• FIG. 24 shows a top view of a pump cartridge and occluder and cross-sectional view of an infusion set tubing according to the present invention; and
• FIG. 25 shows a partially cut-away side view of a pump cartridge loaded into a pump according to the present invention.
DETAILED DESCRIPTION
• 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. Additionally, while various embodiments will achieve some of the objectives set forth above, it will be understood that some embodiments may not achieve all of the objectives and the objectives should not be viewed as limiting the pending claims.
• Referring toFIG. 1, there is shown a perspective view of an infusion set10 and related structures in accordance with the teachings of the prior art. Disposed at oneend10aof the infusion set10 is abag14 for holding parenteral or enteral solutions. Typically, thebag14 is supported by astand18 which holds the bag approximately 6 feet off the floor.
• The opposingend10bof the infusion set10 is connected to a patient (not shown). In a parenteral use, the end of the infusion set10 would have a needle or intra-venous catheter attached thereto which extends into the patient's venous system. In a enteral use, theend10bwould 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.
• Solution flows under gravity from theupper end10aof the infusion set10 to thelower end10b.The pressure on the fluid is approximately 0.433 psi per foot. Thus, if thebag14 is disposed five feet higher than the patient, the pressure at thelower end10bof the infusion set10 is about 2.165 psi. From the extreme height of 8 feet to the floor, the solution in the infusion set10 can reach approximately 3.5 psi.
• To control the flow of solution through the infusion set10, the infusion set is typically mounted through a flow control portion of apump22. Thepump22 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 rotary peristaltic pumps which have a rotor which engages the infusion set10 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.
• Other pumps known in the art, such as linear peristaltic pumps, control solution flow through the infusion set10 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 set10, a highly accurate dose can be provided to the patient.
• While thepump22 controls the solution flow through the infusion set10 when the infusion set is properly loaded, failure to load the infusion set properly in the pump can quickly result in a free flow condition in which the solution flows uncontrolled through the infusion set. To prevent free flow, aclamp26 is disposed along the infusion set10. Typically, theclamp26 is disposed above thepump22. One common type ofclamp26 is a roller clamp which allows some control over the presence of flow and flow volume through the infusion set10. Other clamps simply provide on/off control.
• While the infusion set22 should be mounted in thepump22 prior to or immediately after opening the clamp, this is not always done. There are many situations in a hospital or nursing home setting in which the nurse or physician is called away or otherwise distracted prior to proper placement of the infusion set10. If the clamp has already been opened, the result is that the solution in thebag18 flows uncontrolled into the patient.
• Thus, problems may occur where an infusion set is not properly mounted into the infusion pump. Additionally, problems such as free flow may occur where an individual forgets to load the infusion set into the pump. A third situation where problems may occur is where an infusion set may be accidentally removed from an infusion pump, such as where the infusion set may catch on another piece of equipment or on another person and be pulled from the pump.
• 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 or 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.
• To resolve such concerns, pinch clips may be disposed on the infusion set10. The pinch clip automatically closes the infusion set unless it is properly mounted in the infusion set10. An example of such a pinch clip is disclosed in U.S. Pat. No. 5,810,323.
• While pinch clip 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.
• Turning now toFIG. 2A, there is shown a fragmented, cross-sectional view of an infusion set, generally indicated at100, with a stop oroccluder104 disposed therein. The infusion set100 is formed by one or moreelongate tubes108 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 may be made of materials which are not medical grade.)
• Theoccluder104 has an exterior diameter which is slightly larger than the interior diameter of the tube forming the infusion set100. This causes aportion108aof the tube to stretch slightly as is passes over theoccluder104.
• Theoccluder104 prevents flow through the infusion set100 based on gravity. Thus, the size of theoccluder104 will depend on the material used to form the infusion set. In a presently preferred embodiment, the infusion set100 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. Theoccluder104 is preferably formed out of a plastic (e.g. acrylonitrile butyl styrene (ABS), acrylic (PMMA), polycarbonate, etc.) or a stainless steel ball bearing having an outer diameter of 0.141 inches.
• Because theoccluder104 is larger than the interior diameter of the infusion set100, solution which is under only the force of gravity will back-up behind the occluder and not pass. To prevent theoccluder104 from gradually working its way downstream, aprojection112 can be formed in the infusion set100 or, as explained in detail below, the occluder may be fastened to a connector or some other stationary structure.
• Because this portion of the infusion set100 is formed by an elongate,resilient tube108, increases in pressure will cause the interior diameter of the tube to expand. When thetube108 expands sufficiently, theportion108aof the tube which passes over theoccluder104 allows the solution to flow around the occluder and into thedistal part100bof the infusion set100 as shown inFIG. 2B.
• Preferably, theoccluder104 and infusion set100 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 theportion108aof theelongate tube108 extending over the occluder will expand sufficiently to allow any clinically significant amount of solution to pass.
• While solution hanging in thebag18 may develop 2 to 3 psi due to gravity, it will not have enough pressure to pass by theoccluder104 without application of some external force. In contrast, an enteral feeding pump or other type of pump will typically generate between 5 and 15 psi. When the solution is pressurized to 5 to 15 psi by the pump, the solution is under sufficient pressure to go around theoccluder104 for delivery to the patient. In other words, if the infusion set100 is not properly mounted in the pump so that the pump will generate a higher pressure in theproximal part100aof the infusion set, theoccluder104 inhibits flow to the patient. Thus, there can be no free flow while accommodating flow of solution to the patient when the infusion set100 is properly mounted in the pump.
• Turning now toFIG. 2C, there is shown a fragmented, side cross-sectional view of an alternate configuration of an infusion set, generally indicated at130, and theoccluder104. As with the previous embodiment, theoccluder130 is formed by a small sphere, typically formed of a biologically inert plastic or stainless steel. The infusion set130 is formed of afirst tube134 and asecond tube138. Thefirst tube134 is formed of a resilient polymer or silicone so that the tube may expand with pressure. Thesecond tube138 is typically slightly smaller than thefirst tube134 so that thedistal end134aof the first tube can be attached to the exterior of the proximal end138aof the second tube.
• To ensure that theoccluder104 does not advance distally into thesecond tube138, thesecond tube138 is preferably formed from a material which is semi-resilient or nonresilient and therefore will not accommodate advancement of theoccluder104. To prevent the proximal end138aof thesecond tube138 from forming a seal with theoccluder104, the proximal end preferably has one ormore indentations142 or contours formed therein. Theindentations142 or contours ensure that liquid will be able to flow around theoccluder104 even if the occluder is pressed firmly against the proximal end138aof thesecond tube138.
• When pressures less than about 4 psi are disposed proximally from theoccluder104, thefirst tube134 engages the occluder and prevents liquid from flowing down stream. Once the pressure on the proximal side of theoccluder104 exceeds approximately 4 psi, thedistal end134aof thefirst tube134 expands and allows liquid to flow by in the manner demonstrated byarrows146. Once the pressure subsides, thefirst tube134 returns to its original size and liquid flow terminates until the pressure again is raised above the threshold.
• In use, the infusion set130 andoccluder104 prevent free flow unless the infusion set is placed in engagement with a pump that can generate sufficient pressure (psi) to compel flow around the occluder. Once past theoccluder104, the pressure of the liquid falls to a conventional level and there is no danger to the patient.
• Turning now toFIG. 3A, there is shown a fragmented, cross-sectional view of another embodiment of principle of the present invention. An infusion set160 has a proximal portion160aand adistal portion160b.Disposed between the proximal portion160aand thedistal portion160bis an occluder or stop164. Thestop164 is disposed in the infusion set160 to selectively prevent flow from the proximal portion160ato thedistal portion160b.
• Thestop164 includes aproximal end164aand adistal end164b.Beginning at theproximal end164 is achannel170. As shown inFIG. 3A, the channel has a proximal portion170aand twodistal portions170bwhich are in fluid communication with the proximal portion. While the proximal portion170ais disposed in continuous communication with the interior of the proximal portion160a,each of thedistal portions170bof thestop164 are typically disposed in communication with the sidewall of the infusion set160. The sidewall of the infusion set160 normally prevents fluid flow out of thedistal portions170bof thechannel170.
• Preferably, the sidewall will have sufficient resistance to expansion that a pressure of about 4 psi can be placed in thechannel170 without causing the infusion set160 to radially distend or expand. Thus, if the pressure in the proximal portion160aof the infusion set160 is below about 4 psi, the liquid will not flow through thestop164.
• As shown inFIG. 3A, thestop164 is relatively long. To maintain itself in place, thestop164 frictionally engages the sidewall defining the infusion set160. By providing astop164 which is long, greater surface area is provided to engage the sidewall and prevent thestop164 from being slowly moved downstream.
• Turning now toFIG. 3B, there is shown a fragmented, side cross-sectional view of an infusion set, generally indicated at180. The infusion set180 includes a proximal (upstream) end180aand a distal (downstream)end180bwhich are separated by an occluder or stop184. Thestop184 is similar to thestop164 shown inFIG. 3A in that it has achannel190 with a proximal portion190aand a pair ofdistal portions190b.
• Rather than relying on an elongate body and frictional engagement with the sidewall of the infusion set180, thestop184 has at least oneprojection194 which extends outwardly from the stop to engage the sidewall of the infusion set and prevent advancement. Preferably, theprojection194 is formed by an annular projection, or a plurality of spaced projections extending radially outwardly from thestop184.
• Turning now toFIG. 3C, there is shown a cross-sectional view of the infusion set180 and stop184 ofFIG. 3B. As the pressure in theproximal portion180aof the infusion set180 increases to greater than about 4 psi, the infusion set will distend radially: This allows liquid contained in theproximal portion180aof the infusion set180 to flow into the proximal portion190aof thechannel190, out thedistal portions190bof the channel and into thedistal portion180bof the infusion set. Once the pressure drops below about 4 psi, the infusion set180 will radially retract and the flow in thechannel190 will be terminated as the sidewall of the infusion set covers thedistal portions190bof thechannel190.
• In such a manner, the embodiments shown inFIGS. 3A through 3C prevent free flow by preventing liquid flow under 4 psi. Once the infusion set180 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 thestop184. When combined with the control provided by the various types of infusion pumps, the occluder or stop164 or184 enables a predetermined amount of liquid to flow through infusion set160 or180 while preventing the dangers of free flow conditions.
• FIG. 3D shows a side cross-sectional view of yet another embodiment of an infusion set, generally indicated at200, having an occluder or stop204 disposed therein. The infusion set200 includes a proximal portion formed by afirst tube208 and a distal portion formed by asecond tube212. The proximal end212aof thesecond tube212 is mounted about the exterior of the distal end208aof thefirst tube208.
• Disposed at the distal end208aof thefirst tube208 and the proximal end212aof thesecond tube212 is thestop204. Thestop204 has achannel216 extending from aproximal end204 of the stop to a radially lateral position adjacent thedistal end204bof the stop. Thus, the channel is in fluid communication with liquid in thefirst tube208, but is normally isolated from the interior of thesecond tube212.
• When pressures in the first tube exceed about 4 psi, the proximal end212aof thesecond tube212 radially expands, thereby opening the distal end of thechannel216 and allowing liquid to flow into the distal portion of the infusion set formed by thesecond tube212.
• By positioning thestop204 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 to cause liquid to pass through the infusion set.
• While the embodiments ofFIGS. 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, thestop164,184 or204 could be rotated so that the proximal or upstream portion of the channel is normally closed by the sidewall of the infusion set160,180 or200 and the distal portion of the channel is always in communication with the distal portion of the infusion set.
• FIG. 3E shows yet another embodiment of an infusion set, generally indicated at230, and anoccluder234. Theoccluder234 is disposed in the infusion set230 so as to divide the infusion set230 into a proximal, upstream portion230aand a distal,downstream portion230b.
• Theoccluder234 has achannel238 which extends from aproximal end234aof the occluder to the distal end238bso as to form a passageway through which an infusion liquid, such as enteral feeding solution, may pass. Awall242 is disposed along thechannel238 to selectively prevent flow through the channel. In accordance with the principles of the present invention, thewall242 is pivotably attached to theoccluder234 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 proximal and distal portions of the infusion set. Thus, the same effect could be generated by developing a vacuum downstream from the occluder234). Those skilled in the art will appreciate that the above embodiments could be designed for other thresholds as well.
• Once the desired pressure threshold has been reached, thewall242 will pivot and open thechannel238 to flow. Once the pressure drops, thewall242 will pivot closed in accordance with one method of use. In accordance with another method of use, however, thewall242 can have ascore246 formed therein. Thewall242 is designed to remain occluding the infusion set230 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 thewall242 is generated by the pump (not shown), the infusion set230 must have been properly loaded in the pump for the wall to open. When the infusion set230 is properly loaded in the pump, the pump will prevent free flow. Thus, if the infusion set230 is properly loaded in the pump, the occluder does not need to continue to prevent free flow.
• Turning now toFIGS. 4A and 4B, there are shown fragmented, side cross-sectional views of yet another embodiment of the present invention. An infusion set, generally indicated at250 has anoccluder254 in the form of a duckbill valve formed therein to divide the infusion set250 into a proximal, upstream portion250aand a distal,downstream portion250b.Theoccluder254 is formed of twovanes258aand258bwhich are biased into engagement with one another.
• When the pressure in the proximal portion250aof the infusion set250 is less than about 4 psi, the biasing of thevanes258aand258bkeep them in contact as shown inFIG. 4A. Once the pressure in the proximal portion250aexceeds about 4 psi, the pressure forces thevalves258aand258baway from each other, thereby allowing an infusion liquid to flow through theoccluder254 and into thedistal portion250bof the infusion set250 as shown inFIG. 4B. In order for theoccluder254 to work in such a manner, it is preferable for thevanes258aand258bto extend distally as they engage one another. However, theoccluder254 could be made so that the vanes extend proximally and then buckle once the threshold pressure has been passed.
• Theoccluder254 is shown as being molded integrally with the infusion set250. Such a configuration prevents any concern as to whether theoccluder254 may move during use. However, it is feasible to also form such anoccluder254 as a separate unit and then position it within the infusion set250. Theoccluder254 could be held in place with adhesives or merely a friction fit.
• Turning now toFIG. 5A there is shown a fragmented, side cross-sectional view of an infusion set, generally indicated at300, with anoccluder304 disposed therein. Similar to the embodiment shown inFIG. 2A, the infusion set300 is made of conventional silicone tubing or some other resilient or semi-resilient material, such as latex, polyurethane, etc.
• FIG. 5B shows an end cross-sectional view of the infusion set300 andoccluder304 taken along the plane A-A inFIG. 5A. As shown, the tube defining the infusion set300 forms a seal around theoccluder304 and prevents liquid from passing between the occluder and the tube forming the infusion set.
• Turning now toFIG. 5C, there is shown a side cross-sectional view of the infusion set300 and theoccluder304. Disposed behind the infusion set300 at the location of theoccluder304 is awall308. As will be discussed in additional detail below, thewall308, theoccluder304 and the infusion set300 form a compression valve for selectively allowing liquid to flow through the infusion set.
• FIG. 5D shows a cross-sectional view of the infusion set300 and theoccluder304 taken along the plane B-B inFIG. 5C. The infusion set300 andoccluder304 have been mounted between opposingwalls308 which are spaced apart a distance slightly smaller than the outer diameter of the infusion set. As the infusion set300 is placed between the opposingwalls308, the sides of the tubing forming the infusion set are compressed and held against theoccluder304. This compression also causes the top and bottom300aand300bportions of the tube to extend radially outwardly from theoccluder304, thereby opening aflow path312 above and below the occluder. Theflow paths312 enable liquid in the infusion set300 to flow around theoccluder304 and to flow to the patient.
• In the event that the infusion set300 andoccluder304 are pulled out from between the opposingwalls308, the tube forming the infusion set300 will return to the position shown inFIGS. 5A and 5B, thereby terminating flow through the infusion set. Thus, the configuration shown inFIGS. 5A through 5D prevents free flow of infusion liquids through the infusion set300 so long as the infusion set andoccluder304 are properly mounted between the walls308 (or some analogous engagement surfaces). The infusion set300 andoccluder304 are typically positioned between thewalls308 as the infusion set is being loaded into the pump (not shown). Once properly loaded, the pump controls flow through the infusion set300 and prevents free flow.
• Turning now toFIG. 5E, there is shown a perspective view of a housing of an enteral feeding pump, generally indicated at330, made in accordance with one aspect of the present invention. Thehousing330 includes a pair ofchannels340 and344 for holding a portion of an infusion set tube, such as those discussed with respect toFIGS. 3A through 5D. In use, the tube is placed in onechannel340, wrapped about a motor unit (not shown) which is placed in theopening350, and then positioned in thesecond channel344. If a conventional infusion set is not properly wrapped about the motor unit (or properly installed in other types of pumps) and placed in thechannels340 and344, a free-flow condition may develop. However, the present invention prevents such a situation from developing.
• As shown inFIG. 5E in broken lines, the infusion set354 is mounted in the first andsecond channels340 and344. At least aportion340aof thechannel340 is sufficiently narrow to form walls, similar towalls308 inFIGS. 5A through 5D, which compress the sides of the tube forming the infusion set354, thereby creating a flow path around the occluder (not shown) in the infusion set. If desired, the entire length of thewalls360 which form thechannel340 could be sufficiently close together to compress the infusion set354 and thereby open flow.
• FIG. 5E also shows acover370 which is connected to thehousing330. Thecover370 is pivotable with respect to thehousing330 and includes acatch374 which engages agroove380 on the housing. When thecover370 is closed and thecatch374 engaged in thegroove380, the infusion set354 is securely held in thehousing330 and it is unlikely that the infusion set may be pulled from the pump.
• Rather than having thewalls360 of thechannel344 compress the sides of the infusion set354 to form a compression valve with the sides of the infusion set354, aprojection384 can be mounted on thecover370 so that it is in alignment with the infusion set. When the cover closes, theprojection384 applies a downward force on the infusion set354 thereby forming an open compression valve with the flow channels being disposed in horizontal alignment, rather than vertical alignment as shown inFIG. 5D. Thus, liquid flowing through the infusion set354 passes around the sides of the occluder, as opposed to above and below the occluder.
• 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 set354 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.
• As long as thecatch374 on thecover370 engages thegroove380 on thehousing330, or theprojection384 is maintained in engagement with the infusion set354 at the location of the occluder, the compression valve will remain open. If thecover370 is opened, the force holding the compression valve open is gone and the infusion set354 will retract into the closed position shown inFIGS. 5A and 5B, thereby preventing free flow through the infusion set354.
• Turning now toFIGS. 6A and 6B, there is shown yet another embodiment of the present invention. The infusion set, generally indicated at400, has anoccluder404 disposed therein. Theoccluder404 may be molded in the infusion set400, or may be constructed separately and inserted.
• Theoccluder404 is formed by a first vane408aandsecond vane408bwhich form a duck-bill valve. Thevanes408aand408bare disposed so that they extend proximally (i.e. upstream). As shown inFIG. 6A, thevanes408aand408bnormally engage one other to occlude flow from aproximal portion400aof the infusion set400 to adistal portion400bof the infusion set.
• When pressure is applied to the tubing which forms the infusion set400, thevanes408aand408bmove away from each other sufficiently to allow fluid flow through the infusion set. Thus, inFIG. 6, a compression valve is formed by sliding the infusion set400 between twowalls412 of engagement surfaces so that thevanes408aand408bare 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 set400 remains between thewalls412, projections, etc., fluid flow is enabled. If the portion of the infusion set400 which contains theoccluder404 is pulled from thewalls412 or projections, the occluder will return to the closed position wherein it prevents free flow.
• Preferably, the infusion set400 andoccluder404 will be used in a housing, such as that shown inFIG. 5E. When the infusion set400 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 set400 is pulled out of the housing, theoccluder404 will automatically close—thereby preventing free flow through the infusion set.
• 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. These 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.
• 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.
• Turning now toFIG. 7, there is shown another configuration of an infusion set, generally indicated at400, and an occluder,404 made in accordance with the principles of the present invention. The infusion set400 is formed by anelongate tube108 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.
• Theoccluder404 has an exterior diameter which is slightly larger than the interior diameter of the tube forming the infusion set400, typically about 0.141 inches. This causes a portion408aof the tube to stretch slightly as it passes over theoccluder404.
• Theoccluder404 prevents flow through the infusion set400 based on gravity. Thus, the exact size of theoccluder404 will depend on the material used to form the infusion set400. In a presently preferred embodiment, the infusion set400 is formed from a tube made of silicone rubber, and theoccluder404 is formed from a plastic (e.g. acrylonitrile butyl styrene (ABS), acrylic (PMMA), polycarbonate, etc.) cylinder having an outer diameter of 0.141 inches and a length of about 0.282 inches.
• Because theoccluder404 is larger than the interior diameter of the infusion set400, 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 theoccluder400 as discussed with respect toFIG. 2A, etc.
• While the embodiment shown inFIG. 2A is spherical and the embodiment shown inFIG. 7 is cylindrical, those skilled in the art will appreciate that numerous other embodiments could be used. For example, the dashedline412 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 theoccluder404 need not have a consistent diameter. By having a portion of theoccluder404 extend radially a greater distance than other parts, a portion of the occluder will always engage the wall of the infusion set400, thereby reducing the ability of the occluder to move within the infusion set.
• Turning now toFIG. 8, there is shown still another configuration of aninfusion set420 andoccluder424 made in accordance with the principles of the present invention. The infusion set420 is formed from anelongate tube428 which has afirst portion432 and asecond portion436 which are connected together by aconnector440. Theoccluder424 is attached to theconnector440 by atether442 to prevent the occluder from advancing along thesecond portion436 of theelongate tube428.
• When sufficient pressure is present in a proximal, upstream portion428aof theelongate tube428, thesecond portion432 will expand sufficiently to allow fluid flow past theoccluder424 and into the distal,downstream portion428bof the infusion set420. One advantage of using the connector is that the first portion428aof theelongate tube428 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 set420 without interfering with the interaction between the infusion set and theoccluder424.
• While shown inFIG. 8 as being generally spherical, it should be appreciated that, in accordance with the present invention, theoccluder424 could be a variety of shapes. Additionally, asingle tether442 or a plurality of tethers could be used to hold theoccluder424 to theconnector440.
• FIG. 8A shows a cross-sectional view of another configuration of aninfusion set420, and anoccluder444. Unlike thespherical occluder424 ofFIG. 8, theoccluder444 ofFIG. 8A is disk shaped. To prevent theoccluder444 from rotating in response to fluid pressure and inadvertently opening a fluid flow path, a plurality oftethers442 are used to secure the disk to theconnector440.
• When pressure in the infusion set420 is sufficient, thetube428 will expand and allow fluid flow past theoccluder444. Once the pressure drops below a predetermined threshold, thetube428 will again engage theoccluder444 and terminate flow.
• 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 set420 and related portions are the same as inFIGS. 8 and 8A and are numbered accordingly.
• Theconnector440 is attached by one ormore tethers442 to theoccluder446 to prevent the occluder from moving down stream. Thetethers442 can also be used to keep theoccluder446 in a desired orientation. When sufficient pressure is present, thetube436 expands to allow fluid flow past theoccluder446.
• FIG. 9 shows yet another aspect of the invention wherein the infusion set450 andoccluder454 forms part of a liquid control valve, generally indicated at460. In accordance with the embodiments discussed above, and particularly the discussion surrounding5A through5E, theoccluder454 normally prevents fluid flow through the infusion set. However, squeezing the infusion set on opposing sides of the infusion set sidewall450acaused other portions of the sidewall to extend away from theoccluder454—as demonstrated inFIGS. 5C and 5D.
• Disposed adjacent to the infusion set450 andoccluder454 are a pair ofengagement members464 which are in communication with anactuator468, such as a motor. The communication can be electronic, mechanical or pneumatic, so long as theactuator468 is able to control movement of one or more of theengagement members464.
• When the engagement members are actuated, they apply an inward force to the infusion set450 at the location of theoccluder454 to open a passage way around the occluder and thereby enable fluid flow through the infusion set. When theengagement members464 are adjusted to no longer apply sufficient force to the infusion set450, the infusion set again surrounds theoccluder454 and prevents fluid flow.
• By selectively actuating theengagement members464, the infusion set450 andoccluder454, 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.
• Turning now toFIG. 10, there is shown a perspective view of a clip, generally indicated at480, 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, theclip480 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.)
• Theclip480 includes a base484 which is provided for attachment to the housing of a conventional fluid pump. Typically, thebase484 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 theclip480 can be removed from the pump when an infusion set containing an occluder (such as that represented by the dashed lines488) is not being used with the pump.
• Extending from thebase484 is a fitting490 havingchannel492 formed therein. Thechannel492 is preferably formed with an open end and extends into theclip480. As the infusion set, represented in shadow at488, is inserted into thechannel492,walls494 defining the channel compress the infusion set488 against the occluder (shown as dashed lines498) to open a pair of flow channels between the occluder and the infusion set as shown inFIGS. 5A through 5D.
• As long as the infusion set488 andoccluder498 remain securely held between thewalls494 defining thechannel492, fluid flow is enabled between the occluder and the infusion set. If the infusion set488 is pulled from thechannel492 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 theclip480 on the pump in such a manner that the infusion set488 must be properly loaded in the pump in order to fit within thechannel492.
• FIG. 11 shows a side cross-sectional view of yet another embodiment of the present invention which forms an in-line pump, generally indicated at500. As shown inFIG. 11, a pair ofoccluders504 and508 are disposed in aninfusion line512. Each of theoccluders504 and508 is disposed adjacent anactuator514 and518, respectively. Theactuators514 and518 are configured to selectively apply pressure to theinfusion line512 to selectively open flow channels between the infusion line and theoccluder504 or508 with which each is associated.
• In use, liquid in theinfusion line512 will be held in a proximal portion512awhich is upstream from thefirst occluder504. Thefirst occluder504 prevents the liquid from flowing down stream until adrive mechanism522 causes thefirst actuator514 to apply force to theinfusion line512 adjacent the first occluder. Applying force to theinfusion line512 causes a channel to open between thefirst occluder504 and the infusion line, thereby allowing fluid flow into amiddle portion512bof the infusion line.
• Once themiddle portion512bof theinfusion line512 has had adequate time to fill with liquid, theactuator514 is adjusted so that it no longer applies sufficient force to the infusion line to enable fluid flow around theoccluder504. The liquid in themiddle portion512bof theinfusion line512 is then isolated from the liquid in the proximal portion512a.
• The liquid in themiddle portion512bof theinfusion line512 is prevented from flowing distally or downstream by thesecond occluder508 which defines the distal end of the middle portion. However, once thedrive mechanism522 is actuated to move theactuator518 into forceful contact with theinfusion line512 adjacent theoccluder508, one or more channels are formed between the occluder and the infusion line. The channel(s) opened by theactuator518 squeezing theinfusion line512 form a flow path allowing the liquid contained in themiddle portion512bto flow into a distal,downstream portion512c.Since no occluder or other stop is typically disposed distally from thesecond occluder508, the liquid flowing into thedistal portion512cis delivered to the patient.
• By selectively controlling the application of force by thefirst actuator514 on theinfusion line512 andfirst occluder504 and the application of force by the second actuator on the infusion line andsecond occluder508, a valve, generally indicated at526, is formed which permits a predetermined amount of flow to pass with each series of actuations.
• In a more preferred embodiment, the valve also includes aforce applicator530, such as a plunger, roller or similar device, disposed in communication with themiddle portion512bof theinfusion line512. Theforce applicator530 applies a compressive force to themiddle portion512bof theinfusion line512 to force the liquid contained in themiddle portion512bto flow into thedistal portion512cof theinfusion line512 and on to the patient. Theforce applicator530 ensures that liquid will not simply remain in themiddle portion512bwhen thesecond actuator518 causes a flow path to be formed between thesecond occluder508 and theinfusion line512.
• While applying a compressive force to themiddle portion512bof theinfusion line512 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 themiddle portion512b,the resilient material forming the infusion line will attempt to return to its original, tubular configuration. By closing the flow path between thesecond occluder508 and theinfusion line512 before releasingforce applicator530, a vacuum is formed within themiddle portion512b.Once theactuator514 opens a flow path between thefirst occluder504 and theinfusion line512, the vacuum in themiddle portion512bwill draw liquid into themiddle portion512bas the infusion line returns to its original configuration.
• In each cycle of thevalve526, thefirst actuator514 will open a flow channel between thefirst occluder504 and theinfusion line512 to fill themiddle portion512bwith liquid. Thefirst actuator514 will then allow the flow channel to close. Thesecond actuator518 will then open a flow channel between thesecond actuator508 and theinfusion line512 and theforce applicator530 will apply pressure to the infusion line forming themiddle portion512bso that the liquid in the middle portion will flow into thedistal portion512cand to the patient. Thesecond actuator518 will then allow the flow channel between thesecond occluder508 and theinfusion line512 to close. The process will then be repeated.
• By controlling the interior diameter of theinfusion line512, the distance between thefirst occluder504 and thesecond occluder508, and the movement/size of theforce applicator530, one can obtain a predetermined amount of liquid flow with each cycling of thevalve526. 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 thevalve526. Furthermore, because a rotor is not needed to control flow rate, thevalve526 can be used to make an in-line peristaltic pump which is significantly thinner than conventional peristaltic pumps while maintaining the same accuracy.
• WhileFIG. 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.
• Turning now toFIG. 12A, there is shown a perspective view of a pump, generally indicated at600, which is designed to control fluid flow through an infusion set, generally indicated at604, and into the patient. Thepump600 includes acontrol panel608 which has a plurality ofbuttons610 or other devices for controlling the actuation of the pump. Thepump600 operates to deliver a predetermined dose of enteral feeding solution to a patient by rotation of arotor612.
• The infusion set604 is mounted on the pump so that aresilient portion604aof the infusion set wraps around therotor612. Abracket638 may be used to secure the infusion set604,604a,thedrip chamber620, etc. Each rotation or partial rotation of therotor612 causes a predetermined amount of enteral feeding solution to be advanced through the infusion set604 and delivered to the patient.
• In order to assure that therotor604 is providing the proper amount of enteral feeding solution, adrip chamber620 is formed along the infusion set. Anoptical sensor624 is disposed in theenteral feeding pump600 and monitors the drip rate of the solution in thedrip chamber624. The drip rate of the solution is used to calculate an actual delivery rate of the solution.
• As with the prior art, aportion604bof the infusion set disposed distally from therotor612 is nested in achannel630 in thepump housing600. In accordance with the present invention, theportion604bhas anoccluder634 disposed therein. While the prior art simply used thechannel630 to hold the infusion set604 in contact with the rotors, the inclusion of anoccluder634 provides an improved measure of safety.
• In the prior art, if either theportion604bof the infusion set604 was not properly positioned in thechannel630, a free flow condition could develop in which fluid flow through the infusion set would be unchecked by therotor612. In the present invention, flow through the infusion set604 is not permitted until theportion604bwith theoccluder634 is nested in thechannel630. If theportion604bof the infusion set604 is not properly placed in thechannel630 or is pulled from the channel, theoccluder630 will prevent free flow through the infusion set.
• FIG. 12B shows a close-up, cross-sectional view of the portion of thepump600 having thechannel630 formed therein taken along the line A-A. Thechannel630 receives the infusion set604 in such a manner that it compresses thetube642 against theoccluder634. This causes another portion of thetube642 to extend away from theoccluder634 and thereby open a fluid flow path between the inner wall of the tube and the occluder.
• As shown inFIG. 5D, compressing opposing sides of the infusion set can open fluid flow channels both above and below the occluder. InFIG. 12B, thetube642 of the infusion set604 is pressed against one half of theoccluder634, thereby forming a singlefluid flow channel646 on the opposing side. If theportion604bof the infusion set604 containing theoccluder634 is pulled from thechannel630, the infusion set will engage the occluder and prevent fluid flow.
• Turning now toFIG. 13A, there is shown a connector having still another embodiment of the present invention. Theconnector700 is formed by anadaptor body708 which is used to connect to pieces of tubing together. Most commonly, theadaptor body708 is used to connect a silicone tube segment which engaged the pump rotor, to the remaining tubing of an infusion set (not shown.)Such connectors700 are used on a variety of infusion sets currently in use.
• Theadaptor body708 is formed by aproximal section712, adistal section716, and anannular flange718 which limits the advancement of tubing the proximal and/or distal sections of the adaptor body. Theproximal section712 usually engages the silicone tubing, while thedistal section716 engages the remaining tubing of the infusion set.
• Anarm720 forming a tether/spacer extends proximally from theproximal portion712, and holds an occluder724 a spaced distance from the rest of theadaptor708. Unlike the prior embodiments discussed above, theoccluder724 is generally tear drop shaped when theadaptor708 is standing on end. As shown inFIG. 13a, the distal end724aof theoccluder724 may be squared off. However, it may also be rounded or otherwise contoured. In light of the embodiments discussed above, those skilled in the art will appreciate that a spherical, diamond shape or other shaped occluder could also be used.
• Unlike the tether arrangements discussed in previous embodiments, thearm720 holds theoccluder724 generally rigidly and proximally from the adaptor. In the event thearm720 were to be broken by improper bending of the infusion set in which theadaptor body708 is mounted, theoccluder724 would not be able to move down stream in the infusion set. To the contrary,adaptor body708 would prevent distal movement and the position of the arm and the shape of theoccluder724 would prevent the occluder from completely blocking flow through the tube so long as the designated pressures are being used to properly expand the tube.
• Turning now toFIG. 13B, there is shown a cross-sectional view of theconnector700 shown inFIG. 13A. This view demonstrates the twoflow channels730 which are formed on either side of thearm720. The twoflow channels730 are configured to allow fluid which had flowed passed theoccluder724 to enter thehollow channel734 of theadaptor body708 and to flow downstream from the occluder. An end view of theconnector700 is shown inFIG. 13C.
• The opening in the proximal end of theproximal section712 is preferably about 0.098 inches in diameter and is bisected by thearm720 which is about 0.03 inches thick. Theoccluder724 is preferably spaced about 0.085 inches from theproximal section712, and is provided with a radius of curvature of 0.025 inches on the front end. The rounded portion of the distal end is typically about 0.03 inches long.
• The spacing of theoccluder724 from theproximal section712 and the size of theflow channels730 are sufficient to allow fluid to flow readily through theconnector700 if the pressure is above about 5 psi. If the pressures are below about 5 psi, theoccluder724 will prevent flow of the fluid through theconnector700.
• Having theoccluder724 be formed as part of theconnector700 has several distinct advantages. First, it has been found that theoccluder724 can be formed by molds substantially the same as the molds currently used for such parts. Thus, rather than having to engineer an entirely new product, infusion set manufacturers can readily adapt their molds to add theoccluder724. The cost of adapting the mold is almost negligible. Additionally, the amount of additional plastic used to form the occluder raises the cost of producing theconnector700 by a mere fraction of a cent. This is in contrast to presently available pinch clip occluders and clamps which can cost ten to twenty cents and constitute more than ten percent of the cost of the infusion set. Thus, for almost no cost, the infusion set can be provided with a highly reliable anti-free flow device.
• FIGS. 13D and 13E shown the pumps discussed inFIGS. 5E and 12A, respectively, but configured for use with an adapter/occluder. To avoid excessive repetition, the portions of the pumps which are similar to those inFIGS. 5E and 12A are labeled according.
• As shown inFIGS. 13D and 13E, theconnector700 is preferably mounted to the infusion pump downstream from the pump rotor750 (FIG. 13D) and 760 (FIG. 13E). As the pump rotor750/760 rotates, it will create sufficient pressure to cause the fluid being pumped to pass around theoccluder724 and into the channel734 (FIG. 13B) in theconnector700. The fluid is then free to flow down stream.
• Theconnector700 is highly advantageous because it can be used on most infusion pumps without the need for retrofitting or otherwise modifying the infusion set. It eliminates the need to recess an occluder as shown atnumeral630/634 in the pump shown inFIG. 12A, and eliminates the need for modifiedchannels340/340aor aprojection384 as discussed with respect toFIG. 5A. When mounted in the infusion set, theconnector700 appears substantially the same as the conventional connector and the patient may not even know it is being used unless told. However, the advantages of conventional pinch clip occluders, etc., are achieved without the disadvantages.
• Turning now toFIGS. 14A to 14C, there is shown an alternate embodiment of a connector or adaptor, generally indicated at770, made in accordance with the principles of the present invention. Theconnector770 is typically formed by anadaptor body774 which is used to connect two pieces of tubing together. However, it will be appreciated in light of the present disclosure that such a structure is not required. Most commonly, theadaptor body774 is used to connect a silicone tube segment which engaged the pump rotor, to the remaining tubing of an infusion set (not shown.)
• Theadaptor body774 is formed by aproximal section778, adistal section780, and anannular flange782 which limits the advancement of tubing along the proximal and/or distal sections of the adaptor body. Theproximal section778 usually engages the silicone tubing, while thedistal section780 engages the remaining tubing of the infusion set.
• Rather than being connected by a tether/spacer as shown inFIGS. 13A and 13B which extends into the interior of theproximal section778, the tether/spacer784 forms a pair of arms which connect the occluder or stop788 to theadaptor body774. It has been found that using a pair of arms as the tether/spacer784 decreases the risk of an obstruction preventing flow through theadaptor body774. Because thearms784 are not disposed in alignment with a hollow channel790 in the adaptor body, greater unobstructed area is available for moving enteral feeding solution through the adaptor. This is especially true if the feeding solution is somewhat viscous. The arms forming the tether/spacer784 are also advantageous in that they securely hold the occluder or stop away from theadaptor body774 in a generally rigid manner and reduce the risk that the stop oroccluder788 will be broken off from the adaptor body.
• By matching theoccluder788 with an appropriately sized infusion set tube, a valve can be formed which will open the valve to the flow of liquid once a predetermined pressure threshold has been reached, but generally prevent free flow when the pressure falls below the predetermined threshold. Those skilled in the art will appreciate that the pressure threshold at which the seal between the tubing and theoccluder788 will crack is a function of the relative sizes of both, along with the elasticity of the tubing.
• FIG. 15 shows a top view of yet another embodiment of an in-line occluder, generally indicated at800, made in accordance with the principles of the present invention.FIG. 15A shows theoccluder800 disposed in atube808 of an infusion set. The configuration is referred to generally as an in-line occluder simply to illustrate that the configurations shown herein can be used in conjunction with two tubes as an adaptor, or can be inserted into a single tube. It is presently preferred that the in-line occluder be used as an adaptor for connecting tubing segments. However, it should be appreciated that such is not a requirement and the in-line occluder800 can be disposed completely within a single tube.
• The in-line occluder800 includes abody804 configured to nest in a tube of an infusion set. To this end, thebody804 may include a generally cylindricaldistal portion804aand a taperedproximal portion804b.The taperedportion804bassists in the insertion of the body into the tube.
• Attached to thedistal portion804ais aflange812 which can be used for securing the position of theoccluder800 in an enteral feeding pump. If thebody804 were desired to be disposed completely in a tube, theflange812 could be omitted.
• Attached to theproximal portion804aby one ormore arms816 is an occluder or stop820. As with the previous embodiment, it is preferred to have two arms which connect the proximal portion or stop without extending into a hollow portion (not shown) of the body to thereby minimize interference with fluid flow.
• One concern which has been raised with having a broadly rounded portion of the occluder or stop820 which engages the tubing of an infusion set is that the friction between thestop820 and the tubing can prevent the tubing from resealing against the stop after it has been activated to form a flow channel around the stop. If a seal is not maintained, a free flow condition could result, although it would typically have a very low flow rate.
• In accordance with one aspect of the present invention, it has been found that an improved seal can be achieved by not using broadly rounded stops. More specifically, it has been found that providing thestop820 with an annular detent orchannel824 in a sealingportion828 provides an improved seal and virtually eliminates the risk of leakage. Furthermore, it may be preferred that thechannel824 is defined by relativelysharp edges830. Thus, for example, the edges can have a radius of about 0.003 inches, plus or minus 0.002. The sloped walls at the proximal portion of thestop820 are preferably disposed at an angle between about 60 and 70 degrees, and the back of the stop is preferably beveled at about 120 degrees. With the overall width being about 0.155 inches, thestop820 forms a highly effective occluder in an infusion set tube.
• Ironically, the relatively sharp edges and thechannel824 improve sealing by decreasing the amount of surface area over which the tubing and thestop820 engage each other. The reduction in surface area minimizes the amount of friction for thetubing808 to move from an open position back into a closed position once it is no longer being pinched or once the pressure in the tubing drops below the predetermined threshold. Effectively, thechannel824 allows the tubing to collapse more and to thereby form a better seal.
• Thechannel824 need not be large. To the contrary, a channel which is 30-40/1000ths of an inch deep and 30/1000ths to about 500/1000ths wide works significantly better than a prior art configuration with a broadly rounded stop. More particularly, a channel which is between about 30/1000ths to about 100/1000ths of an inch wide works well in forming an effective seal between the occluder and the tubing. Of course, the remainder of thestop820 can be any desired shape. Thus, as shown inFIGS. 15 and 15A, thestop820 has a blunted proximal end.
• It will be appreciated fromFIG. 15A that thetubing808 is able to form an effective seal around theoccluder820 by engaging theedges830. Theoccluder820 thus prevents flow around the occluder and through the tubing.
• Turning now toFIG. 15B, there is shown an alternate embodiment of an occluder or stop834. Thestop834 will typically be attached to a body, which will not be discussed here. The stop includes a sealingportion838 which is configured to seal against the tubing of an infusion set, etc. The sealingportion838 inFIG. 15B is different than that shown inFIGS. 15 and 15A in that it provides a pair ofbevels840 in the sealingportion838 of the stop. Thebevels840 help to form seals with an infusion tube by reducing friction and minimizing engaged surface area.
• FIG. 15C shows an alternate embodiment of an occluder, generally indicated at850, made in accordance with the principles of the present invention. Theoccluder850 includes astop854. Thestop854 includes broadly roundedsides858 disposed along the sealingportion862. To facilitate sealing between thestop854 and the tubing, one ormore ribs866 are disposed on thestop854. Theribs866 extend outwardly so that engagement of the ribs and the tubing of the infusion set encourages the tubing to flatten out in thesealing area862 and form a seal with the ribs. Again, the reduced surface area of theribs866 which is engaged by the tubing helps to minimize friction and allow the tubing to quickly reseal in the event that it is not being pinched open or forced open due to the pressure in the tubing.
• Turning now toFIG. 15D, there is shown a fragmented view of an occluder, generally indicated at870, which forms astop874. Disposed on thestop874 in thesealing area882 are a pair of annular ribs or rings886. Unlike theribs866 shown inFIG. 15C, theribs886 ofFIG. 15D do not extend radially outwardly to the same extent. Thus, aproximal rib886adoes not extend out as far as thedistal rib886b.Those skilled in the art will appreciate that with the ribs present, the underlying shape of thestop870 becomes less important, as the ribs help form the sealing with the tubing while minimizing friction.
• FIG. 15E shows still another occluder, generally indicated at900 which includes astop904 having a first rib orring908 and a second rib orring912 in thesealing area916. While theribs908 and912 extend generally radially to the same extent, they are different than the embodiment shown inFIG. 15C in that they are positioned close together. It will be appreciated in light of the present disclosure that the most desirable distance between ribs will be a function both of the curvature, if any of the exterior of the ribs, along with the relative elasticity, flexibility and friction of the tubing.
• While theribs908 and912 are relatively thin, broader ribs, such asribs930 and934 on thestop938 can be used as is shown inFIG. 15F. Thus, it will be appreciated that numerous different stop formations can be used to more securely effectuate sealing of the tubing to prevent free flow.
• FIG. 15G shows yet another embodiment of the stop, indicated at950. Thestop950 includes aninner portion954 which is shaped with a configuration generally similar to the shape shown inFIG. 13A. Anouter layer958 is disposed on theinner portion954 to thereby increase its diameter. The outer layer may be formed with ABS and solvent, or in a variety of other ways known to those of skill in the art.
• While shown inFIG. 15G as covering the entire inner portion, those skilled in the art will appreciate that thestop950 could be dipped once or repeatedly into a ABS solution to provide a variety of different shapes. Thus, for example, the inner layer could be covered half way to thereby form a sealing rib about the inner portion at a desired location. Thestop950 could be dipped repeatedly to form multiple sealing ribs, etc.
• FIG. 15H shows a fragmented cross-sectional view of an infusion set having an occluder disposed therein. The occluder and infusion set are similar to those ofFIG. 15 andFIG. 15A and have accordingly been labeled with corresponding reference numerals. Thetubing808 adjacent theoccluder820 is expanded so as to form a gap between the inside bore of the tubing and the occluder. This may commonly occur during use when a pump generates sufficient pressure to force fluid past theoccluder820. After flowing past theoccluder820, the fluid is typically delivered to a patient. It will be appreciated that thetubing808 may be expanded as shown with every pumping stroke and collapse back to the position shown inFIG. 15A between every pumping stroke. Thus, it is important to have a type oftubing808 and anoccluder820 design which allow for consistent sealing between the tubing and the occluder.
• Turning now toFIG. 16 there is shown a cross-sectional view of an infusion set with an occluder disposed therein. WhileFIGS. 5C-D and9-11 above discuss embodiments wherein flow through the infusion set is enabled by compressing opposing sides of the tube against the occluder, it has been found in accordance with the present invention that a preferred configuration involves compressing the tube from generally one side to open a single fluid passage between the occluder and the tubing. Thus, as shown inFIG. 16, anoccluder960 is disposed in atube964. Anactuator968 is disposed to forcefully engage thetube964 to open afluid flow path972 past the occluder.
• Theactuator968 is configured to press on one side of the occluder, but not on both sides as discussed in the previous embodiments. Theactuator968 preferably has twoengagement surfaces976 and980. The twoengagement surfaces976 and980 are preferably spaced apart at an angle of less than 150 degrees, more preferably between about 90 and 135 degrees, and ideally about 110 degrees.
• Because the engagement surfaces976 and980 of the actuator are offset but not opposite one another, the have a tendency to force the tubing in such a way that a singlefluid flow channel972 is formed passed theoccluder960. A singlefluid flow channel972 provides for more area and is less likely to be occluded by a viscous solution or a fibrous solution. When combined with the occluder configurations ofFIGS. 14 and 15, the risk that the occluder will increase the likelihood of an unintendedocclusion is significantly reduced. Furthermore, only requiring the movement of a single actuator decreases the complexity and cost of an enteral feeding pump.
• Turning now toFIG. 17, a front view of a pump is shown. The pump, indicated generally at600, is similar to the pumps shown inFIG. 12A andFIG. 13E. Thebracket638 has been formed such that theconnector700, and thus occluder724 have been mounted further left, towards the center of therotor612 as compared to thepump600 ofFIG. 13E. Theconnector700 andoccluder724, however are held substantially perpendicular to thebracket638 and are not in linear alignment with thetubing980 leading to thepump rotor612. Mounting theconnector700 andoccluder724 further to the left as shown causes the connector and occluder to be held at an angle relative to thetubing980. This creates an area of increased pressure between theoccluder724 andtubing980 on one side of the occluder, and an area of reduced pressure between the occluder and tubing on the opposite side of the occluder, making it easier for thepump rotor612 to push liquid past the occluder.
• It will be appreciated that the degree to which theoccluder724 is pulled off axis relative to thetubing980 determines the degree to which an area of reduced sealing pressure is formed between the occluder and tubing. Thus, theoccluder724 may be oriented such that the sealing pressure between the occluder andtubing980 is slightly reduced, such that the seal is almost broken and easily overcome by therotor612, or such that the seal is broken and a channel is formed between the occluder and tubing. Once the infusion set604,604a,980 is properly mounted in thepump600, therotor612 prevents free flow in the infusion set and theoccluder724 may be bypassed by opening a flow channel between the occluder and tubing. Thus, apump600 and infusion set604 may be designed such that free flow is prevented in the infusion set by the occluder, such that thepump rotor612 prevents flow through the infusion set once the infusion set is properly loaded, and such that a flow channel around theoccluder724 is formed once the infusion set is properly loaded.
• It will be appreciated that many different occluder designs may be used in such a configuration. That is to say that many different occluder designs and stop designs, including ribbed and non-ribbed occluders, may be mounted into a pump so as to maintain the occluder at an angle relative to the tubing and thereby alter the sealing characteristics of the occluder. The occluder may be similar to those shown inFIGS. 13A-13C,14A-14C,15-15H, or18-25.
• Turning now toFIG. 18, a side view of an occluder according to the present invention and a cross-sectional view of infusion set tubing is shown. Theoccluder982 is generally similar to the occluder shown in connection withpump600 ofFIG. 17. Theoccluder982 is attached toconnector984 by a stem orbody992. Aflange996 may be formed between theconnector984 and stem orbody992. Theflange996 may help locate thetubing986,990 or may help secure theoccluder982,connector984, etc. in the pump housing. The stem orbody992 may be formed with ashoulder1000 to helpsecure tubing990 and prevent the rotor612 (FIG. 17) from moving thetubing990. Theshoulder1000 may be formed as angular ridge, or may be rounded as is desired. Aconduit1004 is formed throughconnector984 and stem orbody992 which extends through the end of theconnector984 and which is connected to at least oneopening1008 such that the bore oftubing986 is connected to the bore oftubing990 between theoccluder982 and stem orbody992. The stem orbody992 may be formed withmultiple openings1008 so as to form arms attached to theoccluder982.Tubing990 is typically a flexible tubing, such as silicone tubing, as is necessary for proper operation of the pump600 (FIG. 17).
• In operation, pressurized liquid from the pump600 (FIG. 17) inarea1012adjacent occluder982 may cause thetubing990 adjacent theoccluder982 to expand, forming a flow channel around theoccluder982. Fluid then flows throughopening1008, throughconduit1004, and intotubing986.
• Turning now toFIG. 19, a side view of another occluder according to the present invention is shown. Theoccluder982 is similar to that ofFIG. 18, and similar reference numerals are used. InFIG. 19, thetubing990 which is disposed between theoccluder982 and the pump rotor612 (FIG. 17) is held at anangle1020 relative to theoccluder982 and stem orbody992. Thetubing990 may be held atangle1020 by the position of theoccluder982 andconnector984 relative to thepump rotor612 as is shown inFIG. 17. Alternatively, abracket1024 may be used to hold thetubing990 atangle1020. Thebracket1024 may simply be a projection disposed on the pump600 (FIG. 17) such that once the infusion set is properly loaded into thepump600, theprojection1024 pushes the tubing so as to alter the sealing ability of theoccluder982. Thus,bracket1024 may be a lever or bracket which is moved into place after loading the infusion set, or thebracket1024 may be formed as part of a pump door which is closed after loading the infusion set. Holding thetubing990 atangle1020 creates a greater pressure betweentubing990 andoccluder982 atarea1028 and lower pressure between thetubing990 andoccluder982 atarea1032, making it easier for the pump600 (FIG. 17) to break the seal atarea1032. (While shown with theoccluder982 andconnector984, it will be appreciated that any occluder configuration consistent with those discussed herein or modifications thereof could be used.)
• Turning now toFIG. 20, a side view of another occluder according to aspects of the present invention is shown. Anoccluder982 and stem orbody992 similar to those ofFIG. 19 are shown. Theoccluder982 has been mounted such that theangle1020 between theoccluder982 and stem orbody992 and thetubing990 is increased. This has been accomplished by selecting a mounting location for theoccluder982 relative to thepump rotor988 androllers1036 so as to form the desiredangle1020. Theoccluder982 has been oriented so as to form anangle1020 sufficient to form agap1040adjacent occluder982. According to one embodiment of the invention, the mounting location of the occluder is selected such that amaximum angle1020 of approximately 25 degrees between the axis of the occluder stem orbody992 and the axis of thetubing990 is obtained during the rotation of thepump rotor988. It is preferable thatangle1020 is between 10 and 60 degrees and more preferable that the angle is between 10 and 40 degrees, and even more preferably about 25 degrees.
• Once the feeding set is properly placed in the pump600 (FIG. 17), the tubing is pinched closed adjacent therollers1036 of therotor988, such as atarea1044. Thus, it is not necessary that theoccluder982 continue to prevent flow after properly loading the infusion set into the pump, and a flow channel orgap1040 may be formed adjacent theoccluder982. It will be appreciated that the distance between theoccluder982 and thepump rotor988, and the orientation of theoccluder982 relative to thepump rotor988 determine theangle1020 formed between theoccluder982 andtubing990. Thus, the design of the pump, including the placement and orientation of theoccluder982, may be adjusted to provide the desired amount of sealing pressure adjacent theoccluder982 or thegap1040 formed adjacent theoccluder982 once the infusion set is loaded into the pump.
• Turning now toFIG. 21, a side view of another occluder according to the present invention is shown. Theoccluder982 is similar to that ofFIG. 18 andFIG. 19 and is numbered accordingly. Aprojection1052 is used to apply force to thetubing990 adjacent theoccluder982, so as to push thetubing990 down or sideways and deform thetubing990. Theprojection1052 may be configured such that the projection is moved into place after the infusion set, includingtubing990 andoccluder982, is mounted into the pump600 (FIG. 17). Accordingly, theprojection1052 may be mounted to a lever orarm1056 which is moved into place after mounting the infusion set. Thearm1056 may secure thetubing990 and aid in keeping the infusion set properly loaded in the pump600 (FIG. 17). The lever orarm1056 may be all of or a part of a pump door.
• Thearm1056 andprojection1052 may be configured to displace thetubing990 by varying distances as is desired. Moving the tubing990 a small distance will reduce the pressure required from the pump600 (FIG. 17) to create flow around theoccluder982. Moving the tubing990 a greater distance may open a gap orflow channel1040 adjacent theoccluder982, as is shown inFIG. 21. It will be appreciated that it is typically undesirable to move the tubing such a distance that thebore1060 of thetubing990 is closed adjacent theprojection1052, preventing flow through the tubing.
• Various parameters of the occluder and projection assembly shown may be adjusted to adjust the flow and sealing characteristics of the occluder. The diameter of theoccluder982 may be adjusted relative to the bore of thetubing990. Increasing the diameter of theoccluder982 would increase the cracking pressure and decrease the size of thegap1040, and vice-versa. increasing the length of theprojection1052 and the distance between theprojection1052 and theoccluder982 will alter how far thetubing990 is displaced and how much of agap1040 is formed. According to one embodiment of the invention, the diameter of theoccluder982 is approximately 0.13 inch and is slightly larger than the bore of thetubing990. Theprojection1052 is approximately 0.07 inch wide and is disposed at a distance of approximately 0.08 inch from the tip of theoccluder982, and has a length such that the projection displaces the tubing by a distance of about 0.18 inch.
• Turning now toFIG. 22, a side view of an occluder according to the present invention is shown. The occluder, generally indicated at1070, is shown with adistal body portion1074 which is cylindrical and which is attached to a tapered proximal body portion or stem1078 so as to form ashoulder1082. Although not necessary, the presence ofshoulder1082 helps secure the infusion set tubing to the occluder body. Aflange1086 may be formed on the occluder and may be used to help locate the infusion set tubing or to help secure the occluder in a pump. The distal end of theoccluder1070, such asdistal body portion1074, may also be attached to a pump cartridge or a connector, or may be formed as an integral part of a connector, pump cartridge, or infusion cartridge.
• Anoccluder1090 is attached to theproximal body portion1078 viaarms1094. Typically, a pair ofarms1094 are used, but a single arm may be used if properly formed. Thearms1094 are preferably disposed out of alignment with the center axis of the occluder, such that thearms1094 do not interfere with the flow of liquid through acenter bore1126 formed in theoccluder1070, although a central arm can be used. Theoccluder1090 is designed to engage the infusion set tubing (as shown inFIG. 15A) and prevent undesired flow through the tubing. Applicant has found that theoccluder1090 works better if one ormore ribs1098 are formed on theoccluder1090. Theribs1098 are shown having a generally cylindricalouter surface1102 with chamfered orrounded edges1106. Tworibs1098 are shown according to a presently preferred embodiment, but asingle rib1098 may also be used. Achannel1110 is formed between theribs1098. Aslight bevel1114 may be formed between thechannel1110 and theribs1098. As has been previously discussed, the ribs need not protrude excessively from theoccluder1090. Theribs1098 may protrude between about 0.005 and 0.05 inches, and more preferably about 0.02 inch. Thechannel1110 between theribs1098 may be between about 0.02 and 0.06 inches, and more preferably about 0.04 inches.
• Theoccluder1090 has been formed such that theproximal end1118 of the proximal body portion or stem1078 is slightly greater in diameter than theribs1098. Forming theproximal end1118 greater in diameter than theribs1098 aids in the formation of a flow channel adjacent theribs1098 when the infusion set tubing is pulled off axis as is shown inFIG. 20. Theproximal end1118 of thebody portion1078 may be between about 0.01 and 0.06 inches greater in diameter than theoccluder1090. Theproximal portion1122 of theoccluder1090 may be formed so as to taper to a smaller size as theproximal portion1122 extends away from theribs1098, aiding in the formation of a flow channel around the occluder head when the infusion set tubing is pulled sideways. Theproximal portion1122 of theoccluder1090 should taper somewhat quickly so as to not interfere with the movement of the infusion set tubing as the tubing is pulled sideways. Theproximal portion1122 should taper at an angle of at least 10 degrees, and more preferably at an angle between 20 and 60 degrees. It has also proved advantageous to form theproximal end1122 of theoccluder1090 as a flat surface. While not strictly necessary to the operation of theoccluder1070, forming theproximal end1122 of theoccluder1090 as a flat surface facilitates manufacture of the occluder as plastic may be injected into the occluder mold via the proximal end of the occluder and then finished as a flat surface (1122), allowing for tighter tolerances in theoccluder1090 and relatively simple methods of molding the occluder.
• Turning now toFIG. 23, a side view of another occluder and cross-section of a portion of an infusion set according to the present invention are shown. Theoccluder1070 is formed in a manner similar to theoccluder1070 ofFIG. 22. A taperedproximal body portion1078 is formed adjacent adistal body portion1074 which is smaller in diameter than the adjacent part of theproximal body portion1078 such that ashoulder1082 is formed which helps to secure thepumping portion1142 of the infusion set tubing. Aflange1086 is formed on theoccluder1070 to aid in locating thepumping section1142 anddistal portion1146 of the infusion set. Aconnector1150 is provided whereby thedistal tubing1146 may be attached to theoccluder1070.
• Abore1126 formed through theoccluder1070 allows the flow of fluid through the through the body of the occluder and throughdistal tubing1146 after moving past theoccluder1090. Theribs1098 formed on theoccluder1090 are formed as rounded ribs. Flow is allowed past theoccluder1090 if sufficient pressure exists in the fluid (typically generated by a pump) of if thetubing1142 has been displaced sufficiently to open aflow channel1154 past theoccluder1090 as is shown. The proximal end of thepumping tubing1142 of the infusion set is shown disposed at an angle of about 20 degrees relative to the axis of theoccluder1070. Thetubing1142 may be held at such an angle relative to theoccluder1070 by controlling the orientation of the occluder in the pump, by using a projection such as on the pump door to displace the tubing, etc. Thearms1094 are disposed so as to not interfere with the flow of liquid out of thebore1126 and past theoccluder1090.
• It is important to control thegap1154 between thetubing1142 and theoccluder ribs1098 so as to optimize the flow past the occluder. Asmaller gap1154 will cause a higher fluid pressure drop across theoccluder1070. Conversely, alarger gap1154 will cause a lower fluid pressure drop across theoccluder1070. Typically, a peristaltic pump will work more accurately with a smaller pressure drop across the occluder. Additionally, a typical peristaltic pump will generate about 10 psi of pressure. If the pressure drop across the occluder during fluid flow is higher than 10 psi, the pump will not be able to create flow. Additionally, the feeding solution which might be used in an enteral feeding pump and infusion set may be a mixture containing some food particles instead of being a completely liquid solution. If thegap1154 is smaller than the diameter of any food particles, the particles will tend to clog the infusion line adjacent the occluder and may thus inhibit the flow of the feeding solution through the infusion set.
• Various parameters of the occluder are adjusted to control the cracking pressure of the occluder and aparticular infusion tubing1142, the size of the gap1054, etc. In designing an occluder, it is important to consider that the pressure generated by gravity in a vertically extended infusion set is about 3-4 psi, and that the pressure generated by a typical peristaltic pump is about 10 psi. Thus, the occluder must have a cracking pressure (the pressure at which flow will begin past the occluder) greater than 3-4 psi for an unloaded occluder, and a pressure drop of less than 10 psi across the occluder when feeding solution is flowing past the occluder.
• The distance between theoccluder1090 and theproximal end1118 of the proximal portion of thebody1078 and the difference between the diameter of theproximal portion1118 and the diameter of theribs1098, in combination with the angle of thetubing1142 relative to the center axis of theoccluder1070 and the tubing properties such as elasticity and size determine the size of thegap1154. Shortening the distance between theoccluder1090 and theproximal end1118 of theoccuder body section1078, and increasing the diameter of theproximal end1118 help to increase the size of thegap1154, but tend to decrease the cracking pressure. Increasing the angle of thetubing1142 relative to the occluder axis helps to increase the size of thegap1154. If thetaper1122 of the proximal portion of theoccluder1090 is too shallow, the end of theoccluder1090 may interfere with thetubing1142 as the tubing is pulled sideways. Increasing the diameter of theribs1098 raises the cracking pressure, but lowers the size of the gap1054. It will thus be appreciated that the various dimensions and properties of theoccluder1070 and thetubing1142 may be adjusted to optimize the sealing and flow properties of the occluder/tubing combination.
• The design of theoccluder1070 may be selected so as to facilitate mounting into an infusion pump. Thus, theoccuder body1078,1074 may fit into a corresponding recess in the pump housing. Alternatively, theconnector1150 may fit into a recess formed in the pump housing, or both thebody1074,1078 andconnector1150 may fit into a recess in the pump. Theflange1086 may be used to further secure theoccluder1070, and may fit into a slot or recess formed into the pump housing or may abut a corresponding flange or projection formed on the pump. Theflange1086 may thus inhibit movement of the occluder once loaded into the pump. In the configuration shown inFIG. 17, thepump600 has abracket638 formed thereon and being configured for receiving anoccluder724,1070 (FIG. 23). For such an arrangement, thebody1074,1078 of theoccluder1070 would fit into a slot formed in thebracket638 and theflange1086 would abut thebracket638, preventing movement of the occluder towards thepump rotor612 and maintaining the proper tension in thetubing980.
• Turning now toFIG. 24, a top view of an occluder and pump cartridge according to the present invention is shown. The occluder is indicated generally at1162 and the connector is indicated generally at1166. Theoccluder body1170 is attached to thebody1166 of a pump cartridge, and is in fluid communication withfirst connector1178 which is used to attach thecartridge1166 to a distal portion of an infusion set. Apumping section tubing1182 of the infusion set is attached to the occluder and to asecond connector1186 which is in fluid communication with athird connector1190, used to attach thecartridge1166 to a proximal portion of the infusion set. Anarm1194 may be provided which supports thetubing1182, such as atlocations1198,1202. Thearm1194 may also be used to position and stabilize thecartridge1166 within a pump.
• As shown, thecartridge1166 has many advantages. Thecartridge1166 may be provided with the various sections of the infusion set tubing attached and ready for insertion into a pump. Thecartridge1166 may be easily inserted into a peristaltic pump by placing theloop1206 formed intubing1182 over the pump rotor and then placing the cartridge in a corresponding receiving structure in the pump. Thecartridge1166 and infusion set may easily be loaded into the pump. Additionally, thecartridge1166 provides a larger structure to which theoccluder1162 is attached, providing a more secure manner of mounting theoccluder1162 in the pump and inhibiting movement of theoccluder1162.
• Thecartridge1166 may also facilitate the creation of a flow channel around theoccluder1162. In a manner similar to that shown inFIG. 21, a projection may be used to create a flow channel around theoccluder stop994. Thearm1194 ofcartridge1166 shown inFIG. 24 may be used to supporttubing1182 at1198 so as to facilitate the formation of such a flow channel by pressing against thetubing1182 with a projection atarea1210. Thus, thecartridge1166 may be used with a peristaltic pump having a corresponding recess for receiving thecartridge1166 and a door for closing over at least a part of thecartridge1166 and securing the cartridge into the pump, and a projection on the door. This allows a person to prevent free flow through the infusion line with the occluder prior to loading the infusion line into the pump, and to create a flow channel around the occluder after properly loading the infusion set and cartridge into the pump and closing the pump door. At such a point, the pump rotor prevents free flow through a properly loaded infusion set, as the tubing adjacent the rollers on a pump rotor is pinched closed.
• Turning now toFIG. 25 a side view of a pump cartridge and infusion pump is shown. Thepump cartridge1166 is similar to that ofFIG. 24, and has been loaded by placing theloop1206 oftubing1182 aroundpump rotor1212. Thepump1216 is typically formed withprojections1230 to secure thecartridge1166. Apump door1234 is formed with aprojection1238 which forms aflow channel1242adjacent occluder1162 as is discussed in relation toFIG. 21. Thedoor1234 may also be formed with one ormore projections1246 which contact thecartridge1166 and hold the cartridge securely in thepump1216.
• The infusion set is thereby loaded into thepump1216 in a manner which opens aflow channel1242 around theoccluder1162 after proper loading of the infusion set. Free flow is prevented before and after loading by theoccluder1162 androtor1212 respectively. Opening aflow channel1242 is advantageous as it reduces the pressure drop in the feeding or infusion solution caused by the occluder, and inhibits the blocking of the infusion set adjacent the occluder caused by particles in the infusion solution.
• 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.

Claims (28)

1. A system for selectively preventing flow through a length of tubing, the system comprising:

a length of tubing;

a body having a proximal section disposed in the tubing;

a stop attached to the proximal section of the body and disposed in the tubing; and

an actuator movable into communication with the tubing for pressing on the tubing on one side of the stop to thereby open a flow channel between the tubing and the stop, the actuator comprising a plurality of engagement surfaces for engaging the tubing at a plurality of different locations.

2.-17. (canceled)

18. A method for selectively preventing flow in a tube comprising:

selecting a tube having an occluder disposed therein, the occluder comprising a body having a proximal and a distal end and a stop attached to the proximal end of the body, the stop engaging the interior surface of the tube to prevent flow therethrough;

moving an actuator having a plurality of engagement surfaces disposed thereon into engagement with the tube so that the plurality of engagement surfaces on the actuator engage the tube at different locations on one side of the tube and open a flow channel between the stop and the interior surface of the tube.

19. The method ofclaim 18 wherein the method further comprises selecting an occluder having a pair of generally annular ribs formed on the stop.

20.-49. (canceled)

50. A method for controlling flow in a set for delivering solution to a patient comprising:

selecting a set having a tube having a bore and an occluder having a body having a proximal end configured for disposition in the bore of the tube and having a stop disposed on the proximal end of the body so as to form a seal between the stop and the tube and thereby prevent flow past the stop;

disposing the infusion set in an infusion pump having a pumping mechanism such that the pumping mechanism occludes flow through the tubing when the infusion set engages the pumping mechanism; and

moving an actuator into contact with the tube to engage the infusing set at a plurality of locations with the actuator such that a single flow channel is created adjacent the stop so as to allow flow past the occluder.

51. The method ofclaim 50, wherein the step of moving an actuator comprises moving a pump door having an actuator disposed thereon.

52. A method for selectively controlling free flow in a delivery set, the method comprising:

selecting an delivery set having tubing and having an occluder disposed in the bore of the tubing to prevent flow of solution past the occluder;

mounting the delivery set into an infusion pump; and

engaging the tubing with an actuator so as open a flow channel generally opposite the actuator between the occluder and the tubing of the infusion set to allow flow past the occluder.

53. The method according toclaim 52, wherein the method comprises applying pressure to the tubing to open a flow channel past the occluder generally opposite of the actuator.

54. The method according toclaim 52, wherein the method further comprises applying force to the infusion set tubing to bend the tubing relative to the occluder.

55. A system for delivering fluids, the system comprising:

a tube at least portion of which is radially expandable, the tube having a bore;

an occluder disposed inside the tube to thereby selectively prevent flow through the bore; and

a pump configured to engage the tube and push fluid therethrough, the pump having a structure formed therein for receiving the tube and occluder such that pushing the tube into the structure compresses the tube against the occluder on one side and opens a fluid flow path on an opposing side.

56. The system for delivering fluids ofclaim 55, wherein the structure formed in the pump comprises a channel, and wherein the tube is disposed in the channel.

57. The system for delivering fluids ofclaim 56, wherein the channel has a rounded bottom portion which receives the tube and the occluder.

58. The system for delivering fluids ofclaim 56, wherein the channel has sidewalls which slope toward one another below a midsection of the occluder when the tube and occluder are nested in the channel.

59. The system for delivering fluids ofclaim 55, wherein pump comprises a rotor which engages the tubing to pump fluid therethrough.

60. The system for delivering fluids ofclaim 55 wherein the occluder is generally ball-shaped.

61. A system for delivering solution to a patient comprising:

a pump housing having channel formed therein; and

a tube having an occluder disposed therein;

wherein the tube is mounted in the channel such that at least a portion of the channel applies a compressive force on at least a portion of the tube and opens a flow channel past the occluder.

62. The system ofclaim 61, wherein the occluder is selected from the group consisting of a stop, a vane and a duckbill valve; and

63. The system ofclaim 61, wherein the channel has a bottom and wherein the tube is sandwiched between the occluder and the bottom of the channel.

64. The system ofclaim 63, wherein the flow channel is disposed between the occluder and the tube opposite the bottom of the channel.

65. The system ofclaim 61, wherein the channel is walls tapering to a rounded bottom.

66. A system for selectively delivering fluid through a tube, the system comprising:

a tube having an occluder disposed therein; and

a channel having sides and a bottom, a section of the tube and occluder being disposed adjacent the bottom of the channel to open a single flow path past the occluder.

67. The system ofclaim 66, wherein the tube is radially expandable and contractable, and wherein removing the tube from the channel causes the tube adjacent the occluder to contract about the occluder and close the flow path.

68. The system ofclaim 66, wherein the section of the tube at the bottom of the channel is compressed between the occluder and the bottom of the channel.

69. The systemclaim 66 wherein the single flow path is disposed on a side of the occluder opposite the bottom.

71. A method for delivering a solution to a patient, the method comprising:

selecting a tube having an occluder formed therein to obstruct flow; and

disposing the tube and the occluder into a generally U-shaped channel so as to distend the tube adjacent the occluder and open a flow path between the occluder and the tube.

72. The method ofclaim 63, wherein the U-shaped channel has a rounded end and the method comprises disposing the tube against the rounded bottom to open the flow path on a side of the occluder opposite the rounded bottom.

73. The method ofclaim 62, wherein the U-shaped channel has sloping walls tapering toward the bottom.

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