US20040034331A1 - Integrated medication delivery system - Google Patents

Abstract

A medication delivery system includes a reservoir for storing a supply of medication and a pump assembly coupled to the reservoir. The pump assembly has a pump inlet and a pump outlet and is controllable to provide a flow of medication in the form of a series of pulses. The pump outlet is subdivided into a plurality of legs. A controller is coupled to the pump assembly for controlling the pump assembly and receives a desired flow of medication and responsively controls the pump assembly to provide a series of pulses of medication to provide the desired flow of medication. The series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce an effect of any differential pressure between the legs.

Description

RELATED APPLICATIONS
• This patent application claims priority to U.S. Provisional Patent Application Serial No. 60/451,161 (“TWO SITE INFUSION APPARATUS”) filed Feb. 28, 2003 and is a continuation-in-part application of U.S. patent application Ser. No. 10/083,266, filed Feb. 23, 2002, which claims priority to and all advantages of U.S. Provisional Patent Application No. 60/271,187 which was filed on Feb. 23, 2001.[0001]
FIELD OF THE INVENTION
• The present invention relates generally to the delivery of a pulsatile fluid pulse, and more particularly to an apparatus for controllably dividing a pulsatile fluid flow into two or more pulsatile fluid flows.[0002]
BACKGROUND OF THE INVENTION
• Medication delivery systems are known in the art. Medication delivery systems are used to deliver pain control medication and other medications intra-operatively, subcutaneously, and percutaneously to a patient after a surgical, or some other medical, procedure.[0003]
• It is sometimes desirable to deliver a fluid using a pulsatile fluid flow or series of pulses. For example, some medication delivery systems which utilize a series of pulsatile fluid pulses to deliver medication, are known in the art. Medication delivery systems may be used to deliver pain control medication and other medications intra-operatively or post-operatively, subcutaneously, and percutaneously to a patient after a surgical, or some other medical, procedure.[0004]
• For example, U.S. Pat. No. 5,807,075 to Jacobsen et al. discloses a conventional medication delivery system that includes a base housing and a cassette. The base housing of the '075 patent houses electronic components, such as an electric motor, a power source, and an electronic controller, and the cassette of the '075 patent interacts with a supply of the medication to deliver the medication to the patient.[0005]
• A further example of a conventional medication delivery system is disclosed in U.S. Pat. No. 4,650,469 to Berg et al. This patent discloses a medication delivery system that includes a control module and a reservoir module removably connected to the control module. The control module includes a pump mechanism, valves, a power source, electronic controls, and the like, and the reservoir module includes a container that supplies the medication to be delivered to the patient.[0006]
• It is known to use an electric motor in such medication delivery systems, where a predetermined number at revolutions or cycles of the motor delivers a preset amount of medication. Such systems are known as positive displacement systems. In such systems, pressurization of the medication is a function of the restrictions in the flow path and the time dependent flow of medication through the system.[0007]
• Generally, conventional medication delivery systems provide a flow of medication through an output tube which then is delivered to the patient, as required. However in some procedures, medication is required at two locations with respect to the patient, for example, breast augmentation or reconstruction. Another such procedure where medication delivery is desirable at two sites is an autologous graft procedure where it is desirable to deliver medication at both the graft and the donor sites. If the medication provided by the delivery system is pumped through a “Y” connection, then there are several reasons that the medication may not be delivered to each site or location in the desired proportion. First, unequal pressure at the two infusion sites due to elevation or intracompartmental pressure sets up a siphon where flow occurs from one side to the other side in the period between pulses. Furthermore, natural or unintended variations in flow restriction between the two sides of the “Y” and/or the previously mentioned unequal infusion site pressures may shift the proportion of the flow split, as more flow will follow the path of decreased resistance. This is undesirable.[0008]
• In a mechanical system experiencing laminar flow of a non-compressible fluid, a similar phenomenon occurs whereby the pressure between two points is directly proportional to the mass flow rate through the system and the flow restriction between the two points.[0009]
• This can be expressed as ΔP={dot over (M)}R, where[0010]
• ΔP=Pressure Differential (psi)[0011]
• M Mass Flow Rate (cc/sec)[0012]
• R=Flow Restriction (psi/[cc/sec])[0013]
• Similarly,[0014]$\stackrel{.}{M}=\frac{\Delta P}{R}$

  
• In other words, the instantaneous flow rate in a single-lumen system is directly related to the instantaneous pressure between two points separated by a known flow restriction, and it is inversely proportional to the value of the restriction between those two points.[0015]
• In a scenario where more than one distal site is linked to the fluid path, the overall flow rate to both sites as well as the percent flow reaching each site is also related to pressure and restriction. Though capacitance in the system may cause a phase shift in the instantaneous flow rate from location to location, the overall flow from the lumen upstream of the branching node will equal the sum of the overall flow coming through each outlet lumen (leg).[0016]
• In this scenario, the instantaneous flow rate along each leg will be directly related to the difference in pressure between the branching node and the distal outlet of the leg, and it will be inversely proportional to the flow restriction along that leg. The mass flow rate through any given outlet lumen may be calculated as follows:[0017]$\stackrel{.}{M_i}=\frac{\Delta P_i}{R_i}=\frac{P_0-P_i}{R_i}$

  
• where[0018]
• ΔPi=P0−Pi[0019]
• P0=Pressure at branching node (psi gage)[0020]
• Pi=Pressure at outlet of lumen i (psi gage)[0021]
• Ri=Flow Restriction of outlet lumen i (psi/[cc/sec])[0022]
• The total flow through all legs is then[0023]${\stackrel{.}{M}}_{\mathrm{total}}=\sum _{i=1}^n{\stackrel{.}{M}}_i=\sum _{i=1}^n\frac{P_0-P_i}{R_i},$

  
• and the percent flow to any given outlet lumen is[0024]$\%F=\left(100\right)\frac{\stackrel{.}{M_i}}{{\stackrel{.}{M}}_{\mathrm{total}}}.$

  
• If a pump with a pulsatile flow delivery system is connected to a fluid delivery path, and it is desired to controllably divide the flow between the multiple outlet sites, the flow restrictions in each outlet lumen may be designed so as to facilitate the desired flow distribution. With each pulse of fluid flow from the pump, the pressure in the inlet lumen and the branching node will rise—with a lower system capacitance before the node leading to a more steep pressure rise. After the pump finishes introducing fluid to the path, a pressure drop will be observed as fluid drains through the outlet lumens, emptying the fluid stored by the capacitance of the system. As stated before, the instantaneous flow rate during this process is related to the pressure differential and the flow restriction; as the pressure drops asymptotically to an equilibrium level, so will the flow decrease proportionally.[0025]
• If the pressure at all outlet sites is the same, then ΔP will be the same for each outlet lumen and the flow distribution may be directly controlled by the flow restrictors alone.[0026]
• However, if the pressures of the outlets are not equal and not constant, then additional measures are required to equally or accurately distribute the flow as desired to all sites. This can be accomplished by making the pressure at the node high enough that the variation in pressures at each site do not contribute greatly to percent variation in pressure differential. In other words, if P[0027]₁≠P₂but P₀>>P₁and P₀>>P₂, then ΔP₁=ΔP₂. If ΔP1 and ΔP2 are then similar, the restriction level of each lumen may once again be relied upon to provide the control necessary to balance the flow percentage to each lumen outlet.
• However, in the case of a pulsatile pump, the time-dependent pressure profile may not provide the necessary conditions to keep P[0028]₀>>P₁and P₀>>P₂. A substantial portion of fluid flow occurs as the pressure profile drops during the drain cycle mentioned above, and as the pressure drops, the ΔPi of the various paths will deviate farther and farther from each other, in relation to the difference in Pi at each outlet location.
• One solution would be to provide a check valve in each leg after the “Y” connection. This solution presents several problems, namely, there is a time delay added by the opening and closing of the check valve and differences in manufacturing tolerances contributing to the delay may also lead to uneven delivery of the medication. Furthermore, most check valves restrict flow when open, and unequal or uncontrollable variations in this restriction would lead to unequal flow.[0029]
• Another solution would be to provide a large fluid resistor (small orifice) in each leg. Correctly sizing this orifice would cause the pressure to rise substantially higher than the downstream pressure differences. This pressure could be driven up over several pulses. If the pressure remained higher than the highest downstream pressure, no backflow due to siphoning could occur. Furthermore, the difference in the pressure drop in the two downstream legs could be controlled to remain relatively equal. This solution presents several problems. First, if the pump has a user selectable flow rate, the size of the glass orifice must be fixed to work with the lowest possible flow rate. If a higher flow rate were then selected, the level of restriction would cause an increase in pressure beyond acceptable limits for safety or function the system or its components, including features such as an occlusion sensor.[0030]
• The present invention is aimed at one or more of the problems set forth above.[0031]
SUMMARY OF THE INVENTION AND ADVANTAGES
• In one aspect of the present invention, a medication delivery system is provided. The system includes a reservoir for storing a supply of medication and a pump assembly coupled to the reservoir. The pump assembly has a pump inlet and a pump outlet and is controllable to provide a flow of medication in the form of a series of pulses. The pump outlet is subdivided into a plurality of legs. A controller is coupled to the pump assembly for controlling the pump assembly and receives a desired flow of medication and responsively controls the pump assembly to provide a series of pulses of medication to provide the desired flow of medication. The series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce an effect of any differential pressure between the legs.[0032]
• In another aspect of the present invention, a method for delivering medication using a medication delivery system is provided. The method includes the steps of storing a supply of medication, receiving a desired flow of medication, and providing a flow of medication from the supply of medication in the form of a series of pulses. The flow is provided through an outlet and subdivided into a plurality of legs. The series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce an effect of any differential pressure between the legs.[0033]
BRIEF DESCRIPTION OF THE DRAWINGS
• Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:[0034]
• FIG. 1A is a perspective view of an integrated medication delivery system according to the subject invention with an infusion tube set;[0035]
• FIG. 1B is a perspective view of an underside of the system illustrating a system mounting clip for securing the system to a patient;[0036]
• FIG. 2A is an exploded perspective view of the system illustrating a medication reservoir, a base housing, reservoir casings, a pump assembly, and a carrying strap of the system;[0037]
• FIG. 2B is an exploded perspective view of the system illustrating a removable overlay label, a patient label, and a top housing of the base housing for assembly to the system;[0038]
• FIG. 3 is an exploded perspective view of the system illustrating a port, a plunger, the pump assembly including a motor and first and second pinch levers, an actuator, and the base housing including an integral storage cavity for the carrying strap;[0039]
• FIG. 4 is an exploded perspective view of the system illustrating an underside of the top housing, at least one control button, an electronic controller and display, and a detection film having a cantilever portion;[0040]
• FIG. 5 is an exploded perspective view of the pump assembly;[0041]
• FIG. 6A is a partially cross-sectional side view of a cam shaft, the pump assembly, and the first and second pinch levers illustrating the pinch levers in a closed position to pinch medication inlet and outlet tubes;[0042]
• FIG. 6B is a partially cross-sectional side view of the system, as disclosed in FIG. 6A, illustrating the first pinch lever in an open position and the second pinch lever in a closed position to draw medication into the pump assembly;[0043]
• FIG. 6C is a partially cross-sectional side view of the system, as disclosed in FIG. 6A, illustrating the first pinch lever in a closed position and the second pinch lever in an open position to displace medication from the pump assembly;[0044]
• FIG. 6D is a partially cross-sectional side view of the system, as disclosed in FIG. 6A, in combination with the plunger and the actuator, with the actuator retaining the pinch levers in the open position;[0045]
• FIG. 7 is a partially cross-sectional side view of the pump assembly;[0046]
• FIG. 8 is an exploded perspective view of the port and the plunger;[0047]
• FIG. 9 is an enlarged partially cross-sectional top view of the plunger disposed in the port illustrating a first, second, and third fluid connector;[0048]
• FIG. 10 is a partially cross-sectional side view taken along line[0049]10-10 in FIG. 9 illustrating a seal disposed about the plunger being depressed by leak ribs extending from the port;
• FIG. 11A is a partially cross-sectional top view of the system with the plunger in an off-position;[0050]
• FIG. 11B is a partially cross-sectional view of the port and the plunger disposed in the port in the off-position from FIG. 11A;[0051]
• FIG. 12A is a partially cross-sectional top view of the system with the plunger in a fill-position such that the system can be sterilized and filled with medication;[0052]
• FIG. 12B is a partially cross-sectional view of the port and the plunger disposed in the port in the fill-position from FIG. 12A additionally illustrating a syringe for moving the plunger into the fill-position and a fluid cap for sterilization;[0053]
• FIG. 13A is a partially cross-sectional top view of the system with the plunger in a fluid delivery-position such that the medication can be delivered to the patient;[0054]
• FIG. 13B is a partially cross-sectional view of the port and the plunger disposed in the port in the fluid delivery-position from FIG. 13A additionally illustrating a connector from the infusion tubing set;[0055]
• FIG. 14A is an enlarged perspective view of the actuator;[0056]
• FIG. 14B is a perspective view of an alternative embodiment for the actuator including a control contact disposed at a distal end of an actuation arm;[0057]
• FIG. 15A is a partially cross-sectional side view of a blockage detection system according to the subject invention when the medication outlet tube is in a normal condition;[0058]
• FIG. 15B is a partially cross-sectional side view of the blockage detection system of FIG. 15A when the medication outlet tube is in an expanded condition due to a blockage;[0059]
• FIG. 16A is a partially cross-sectional side view of an empty detection system according to the subject invention when the medication inlet tube is in a normal condition;[0060]
• FIG. 16B is a partially cross-sectional side view of the empty detection system of FIG. 16A when the medication inlet tube is in a collapsed condition due to a depletion in the supply of the medication;[0061]
• FIG. 17 is a perspective view of a support platform with the medication inlet and outlet tubes which also illustrates alternative embodiments for the blockage detection system and the empty detection system where a coating is applied to the medication inlet and outlet tubes;[0062]
• FIG. 18A is a top perspective view of the system engaged with a testing instrument for confirming proper operation of the system after assembly and prior to use;[0063]
• FIG. 18B is a bottom perspective view of the system engaged with a second testing instrument for confirming proper operation of the system after assembly and prior to use;[0064]
• FIG. 19 is a perspective view of the patient using the carrying strap as a shoulder strap to carry the system;[0065]
• FIG. 20 is an enlarged top perspective view of the integral storage cavity defined within the base housing of the system;[0066]
• FIG. 21 is a perspective view of a surgeon or patient removing the removable overlay label to reveal the patient label;[0067]
• FIG. 22 is a plan view of one embodiment of the removable overlay label having a one version of a first set of explanatory indicia;[0068]
• FIG. 23 is a plan view of a further embodiment of the removable overlay label having another version of a first set of explanatory indicia;[0069]
• FIG. 24 is a plan view of the patient label having a second set of explanatory indicia;[0070]
• FIG. 25 is a block diagram schematically illustrating a control system for the integrated medication delivery system of the subject invention;[0071]
• FIG. 26 is an electrical diagram illustrating portions of a watchdog circuit of the control system; and[0072]
• FIG. 27 is an electrical diagram illustrating further portions of the watchdog circuit of the control system.[0073]
• FIG. 28 is graphical illustration of a tube set divided into a plurality of legs, according to an embodiment of the present invention;[0074]
• FIG. 29A is a graph illustrating a series of pulses divided into first and second groups, according to an embodiment of the present invention;[0075]
• FIG. 29B is a graph of an exemplary pressure profile during a group of pulses in which the system pressure is allowed to drop to the outlet pressure after the group;[0076]
• FIG. 29C is a graph of an exemplary pressure profile during 2 groups of pulses in which a mechanism is in place to hold system pressure at or above a predetermined level after the first group;[0077]
• FIG. 29D is a diagrammatical illustration of a tube set having a Y-divider, at least one check valve and a flow restrictor in each leg, according to an embodiment of the present invention;[0078]
• FIG. 30 is a first isometric view of a two site infusion apparatus, according to an embodiment of the present invention;[0079]
• FIG. 31 is second isometric view of the two site infusion apparatus of FIG. 1;[0080]
• FIG. 32 is a top down view of the two site infusion apparatus of FIG. 1;[0081]
• FIG. 33 is a side view of the two site infusion apparatus of FIG. 1;[0082]
• FIG. 34 is a bottom view of the two site infusion apparatus of FIG. 1;[0083]
• FIG. 35 is a first cut-away view of the two site infusion apparatus of FIG. 1; and,[0084]
• FIG. 36 is a second cut-away view of the two site infusion apparatus of FIG. 1.[0085]
DETAILED DESCRIPTION OF THE INVENTION
• Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, an integrated[0086]medication delivery system10 is generally disclosed at10. The integratedmedication delivery system10, hereinafter described as thesystem10, delivers medication to a patient12 (refer to FIG. 19). More specifically, thesystem10 is primarily used throughout the medical profession to deliver pain control medication and other medications to the patient12 after a surgical, or some other medical, procedure. As disclosed in FIG. 1B, thesystem10 is used in combination with an infusion tube set14 to deliver the medication to thepatient12. The infusion tube set14 is described below.
• The[0087]system10 of the subject invention is also suitable for complete sterilization by a sterilization fluid including, but not limited to, ethylene oxide (EtO) gas. Although not ideal, certain liquids may even be used to sterilize thesystem10. For descriptive purposes only, the terminology of “medication” and of “sterilization” fluid may also be described throughout simply as a fluid.
• Referring primarily to FIGS.[0088]2A-3, thesystem10 includes abase housing16. Thebase housing16 is further defined as abottom housing18, amiddle housing20 mounted to thebottom housing18 and atop housing22, i.e., a cover. Thehousings18,20,22 are preferably mounted together via screws23. Thesystem10 also includes amedication reservoir24 disposed about thebase housing16. More specifically, thereservoir24 is disposed about themiddle housing20. Thereservoir24 stores the supply of medication that is to be delivered to thepatient12. Preferably, thereservoir24 is formed of a flexible, yet durable plastic material. Thesystem10 further includes areservoir casing26 disposed between the bottom andtop housings18,22. Thereservoir casing26 at least partially surrounds thereservoir24 to protect the medication that is to be delivered to thepatient12. The preferred embodiment of the subject invention includes tworeservoir casings26 that surround thereservoir24 to protect the medication. Of course, it is to be understood that thereservoir casing26 may be a unitary component and still adequately surround thereservoir24 to protect the medication. Thereservoir casing26 is particularly useful when thepatient12 is carrying thesystem10. Carrying of thesystem10 is described below.
• Referring primarily to FIGS. 2A, 3, and[0089]5-6D, apump assembly28 is supported by thebase housing16. Specifically, thepump assembly28 is mounted to thebottom housing18. As understood by those skilled in the art, thepump assembly28 is responsible for delivering the medication to thepatient12. As described below, thepump assembly28 also serves to prevent inadvertent delivery of the medication to thepatient12.
• As disclosed best in FIG. 5, the[0090]pump assembly28 includes apump housing30 having apump inlet32 and apump outlet34. Thepump housing30 also has at least onedetent36. The at least onedetent36 is described below. Thepump inlet32 and thepump outlet34 alternate between an open and a closed state to deliver the medication to thepatient12. Referring now to FIGS.3, and6A-6D, afirst pinch lever38, also referred to as a pinch valve, is disposed at thepump inlet32 and asecond pinch lever40 or valve is disposed at thepump outlet34. Thefirst pinch lever38 functions to alternate thepump inlet32 between the open and the closed state, and thesecond pinch lever40 functions to alternate thepump outlet34 between the open and the closed state.
• As FIGS. 6B and 6C disclose, the[0091]first pinch lever38 is moveable between an open position (FIG. 6B) and a closed position (FIG. 6C) to control a flow of the medication into thepump housing30 through thepump inlet32, and thesecond pinch lever40 is moveable between an open position (FIG. 6C) and a closed position (FIG. 6B) to control a flow of the medication from thepump housing30 through thepump outlet34. Thepump assembly28 further includes amotor42 that is operatively engaged to the first and second pinch levers38,40 for moving theselevers38,40 into the open position such that the medication can be delivered to thepatient12. Themotor42 includes a driving output shaft, not shown in the Figures, for driving thepump assembly28. Apower source43 is integrated into thesystem10 to provide power to thesystem10, including themotor42. Preferably, the power source includesbatteries45 andbattery contacts47.
• As shown in FIG. 6A, the[0092]first pinch lever38 is normally-biased to maintain thepump inlet32 in the closed state and thesecond pinch lever40 is normally-biased to maintain thepump outlet34 in the closed state. To accomplish this, at least onebiasing device44 is included in thepump assembly28. Preferably, the at least onebiasing device44 is a compression spring as shown, but not numbered, throughout the Figures. However, it is to be understood that the at least onebiasing device44 may be any device that is suitable for normally-biasing at least one, if not both, of the first and second pinch levers38,40 into the closed position. The at least one biasing44 device engages at least one of the first and second pinch levers38,40 and works in conjunction with themotor42 to normally bias at least one of the first and second pinch levers38,40 into the closed position. As such, if themotor42 fails during delivery of the medication, then the first and second pinch levers38,40 are biased into and thereafter maintained in the closed position to prevent the inadvertent delivery of the medication to thepatient12. Themotor42 is able to move the first and second pinch levers38,40 into the open position despite the bias of the at least onebiasing device44.
• In the preferred embodiment of the subject invention, the at least one[0093]biasing device44 comprises a first46 and a second48 biasing device. Thefirst biasing device46, preferably a compression spring, engages thefirst pinch lever38, and thesecond biasing device48, also preferably a compression spring, engages thesecond pinch lever40. As disclosed in FIG. 6A, the first andsecond biasing devices46,48 maintain the first and second pinch levers38,40 in the closed position during failure of themotor42 thereby preventing the inadvertent delivery of the medication to thepatient12. More specifically, the closedfirst pinch lever38 prevents the medication from being drawn into thepump assembly28 through thepump inlet32, and the closedsecond pinch lever40 prevents the medication from being displaced from thepump assembly28 through thepump outlet34.
• Referring primarily to FIGS.[0094]5-6D, to effectively operate thesystem10 and move the first and second pinch levers38,40 for delivery of the medication to thepatient12, thepump assembly28 of the subject invention further includes acam shaft50 supported on thepump housing30. Thecam shaft50 is geared to themotor42, via a number ofgears52, to operatively engage themotor42 to the first and second pinch levers38,40. Thecam shaft50 is described in greater detail below.
• As disclosed best in FIGS. 5 and 7, the[0095]pump assembly28 also includes apiston54 disposed in thepump housing30. Themotor42 moves thepiston54 within thepump housing30 to draw the medication into thepump housing30 when thefirst pinch lever38 is in the open position and thesecond pinch lever40 is in the closed position (see FIG. 6B). Themotor42 also moves thepiston54 within thepump housing30 to displace the medication from thepump housing30 when thefirst pinch lever38 is in the closed position and thesecond pinch lever40 is in the open position (see FIG. 6C). Thepiston54 includes anactuation end56 and a pumpingend58. Adiaphragm seal60 is disposed at the pumpingend58 of thepiston54. Thediaphragm seal60 is secured at the pumpingend58 of thepiston54 by apiston cap62. Thepiston54 also includes at least oneslot62 at theactuation end56. The at least onedetent36 of thepump housing30, originally introduced above, engages the at least oneslot62 at theactuation end56 of thepiston54 to prevent unwanted rotation of thepiston54 as thepiston54 is moved within thepump housing30 by themotor42 and thecam shaft50.
• The[0096]cam shaft50 supports first and secondoutside cams64,66 and aninside cam68. Theinside cam68 of thecam shaft50 is disposed between the first and secondoutside cams64,66. The firstoutside cam64 engages thefirst pinch lever38 to move thefirst pinch lever38 between the open and closed position, and the secondoutside cam66 engages thesecond pinch lever40 to move thesecond pinch lever40 between the open and closed positions. Theinside cam68 engages theactuation end56 of thepiston54 to move thepiston54 within thepump housing30.
• Referring to FIG. 5, the first and second[0097]outside cams64,66 include a plurality ofslits70 along anouter circumference72 of thecams64,66. Theseslits70 are used during assembly and testing of thesystem10 to confirm dimensional tuning of thecams64,66. Also, at least one of the first and secondoutside cams64,66, preferably the firstoutside cam64, includes anassembly slot74 defined within theouter circumference72 of thecams64,66. Thisassembly slot74 facilitates assembly of thepump assembly28. In particular, thisassembly slot74 facilitates mounting of thecam shaft50, including thecams64,66, after the first and second pinch levers38,40 have already been incorporated into thesystem10.
• Each of the first and second pinch levers[0098]38,40 comprise acam follower76 and lever guides78. The lever guides78 are described below. Thecam followers76 of the pinch levers38,40 are engaged by thecam shaft50 for alternating movement of the first and second pinch levers38,40 between the open and closed positions such that the medication can be delivered to thepatient12. More specifically, thecam follower76 of thefirst pinch lever38 is engaged by the firstoutside cam64 for alternating movement of thefirst pinch lever38 between the open and closed positions, and thecam follower76 of thesecond pinch lever40 is engaged by the secondoutside cam66 for alternating movement of thesecond pinch lever40 between the open and closed positions. Even more specifically, each of the first and secondoutside cams64,66 include internal cam surfaces80. As disclosed in FIGS.6A-6D, thecam follower76 of thefirst pinch lever38 rides within theinternal cam surface80 of the firstoutside cam64 for alternating movement of thefirst pinch lever38, and thecam follower76 of thesecond pinch lever40 rides within theinternal cam surface80 of the secondoutside cam66 for alternating movement of thesecond pinch lever40.
• Referring primarily to FIGS.[0099]3, and8-10, thesystem10 further includes aport assembly82 that enables various fluids, such as the medication or the sterilization fluid, to flow into, from, and within thesystem10. Theport assembly82, hereinafter described as theport82, extends from thebase housing16. More specifically, theport82 extends from themiddle housing20. Theport82 is in fluid communication with thereservoir24 and thepump assembly28. During sterilization, theport82 provides access for the sterilization fluid to flow into thereservoir24 and thepump assembly28. During filling, theport82 provides access for the medication to flow into thereservoir24 and thepump assembly28. During delivery of the medication to thepatient12, theport82 provides access for the medication to be delivered to thepatient12.
• Referring particularly to FIGS.[0100]9, and11A-13B, theport82 includes anelongated housing84. Theelongated housing84 includes aproximate end86, adistal end88, and aninterior wall90 defining afluid chamber92 between the proximate and distal ends86,88. It is theproximate end86 of theelongated housing84 that extends from thesystem10 to provide access for the fluid to flow both into and from thesystem10. Theport82 further includes afirst fluid connector94, asecond fluid connector96, and a thirdfluid connector98. Thefirst fluid connector94, alternatively referred to as an outlet of theport82, extends from theelongated housing84 to allow the fluid to flow from thefluid chamber92 into thepump assembly28. Thesecond fluid connector96, alternatively referred to as an inlet to theport82, extends from theelongated housing84 to allow the fluid to flow from thepump assembly28 into thefluid chamber92. The thirdfluid connector98, alternatively referred to as an access to thereservoir24, extends from theelongated housing84 to allow the fluid to flow between thefluid chamber92 and thereservoir24. In the preferred embodiment of the subject invention, there are two thirdfluid connectors98, onethird fluid connector98 extending from opposite sides of theelongated housing84.
• Referring primarily to FIGS. 3, 6D,[0101]8-10, and11A-13B, theport82 further includes aplunger100. Theplunger100 is disposed in thefluid chamber92 of theport82 and is moveable between an off-position (FIGS.11A-11B), a fill-position (FIGS.12A-12B), and a fluid delivery-position (FIGS.13A-13B). As disclosed in FIGS.11A-11B, in the off-position, the first, second, and thirdfluid connectors94,96,98 are isolated from theproximate end86 of theelongated housing84 by theplunger100. As a result, the flow of fluid through theport82 is prevented. As disclosed in FIGS.12A-12B, in the fill-position, the first and thirdfluid connectors94,98 are in fluid communication with theproximate end86 of theelongated housing84. As a result, a fluid flow path, shown but not numbered in FIGS.12A-12B, is provided between theproximate end86 of theelongated housing84, themedication reservoir24, and thepump assembly28 such that the fluid can be filled through theproximate end86 of the housing and into themedication reservoir24 and thepump assembly28. This fluid flow path is defined between theport82, thereservoir24, and thepump assembly28 such that the flow of sterilization fluid through the fluid flow path is continuous during sterilization of thesystem10. The fill-position of theplunger100 is utilized when thesystem10 is being sterilized with the sterilization fluid and also when thesystem10 is being filled with medication. As disclosed in FIGS.13A-13B, in the fluid delivery position, the first, second, and thirdfluid connectors94,96,98 are in fluid communication with theproximate end86 of theelongated housing84 and with each other for supplying thepump assembly28 and for delivering the fluid to thepatient12.
• Referring primarily to FIGS. 3, 6D,[0102]11A,12A,13A, and14A-14B, thesystem10 further includes anactuator102 disposed in thebase housing16. Theactuator102 is moveable between a disengaged position and an engaged position. The disengaged position of theactuator102 is described below. As disclosed in FIG. 6D, in the engaged position, theactuator102 operatively engages thepump inlet32 and thepump outlet34 to retain, i.e., lock, both thepump inlet32 and thepump outlet34 in the open state during sterilization. With thepump inlet32 and thepump outlet34 in the open state, the sterilization fluid can penetrate throughout theentire system10 to completely sterilize thesystem10. That is, the sterilization fluid can penetrate into thereservoir24, thepump inlet32, thepump housing30, and thepump outlet34 to completely sterilize thesystem10.
• More specifically, the[0103]actuator102 interacts with the first and second pinch levers38,40 to retain both thepump inlet32 and thepump outlet34 in the open state during sterilization. In the engaged position, theactuator102 moves thefirst pinch lever38 away from thepump inlet32 into the open position to retain thepump inlet32 in the open state, and theactuator102 moves thesecond pinch lever40 away from thepump outlet34 into the open position to retain thepump outlet34 in the open state. Theactuator102 retains both the first and second pinch levers38,40 in the open position for sterilization despite the bias of the at least onebiasing device44.
• On the other hand, when the[0104]actuator102 is in the disengaged position, as indicated by the absence of the actuator102 from FIGS.6B-6C, theactuator102 is operatively disengaged from thepump inlet32 and thepump outlet34. Theactuator102 is in the disengaged position when it is necessary to deliver the medication to the patient12 such that thepump inlet32 and thepump outlet34 can alternate between the open and closed states to deliver the medication thepatient12. Disengagement of the actuator102 permits thepump inlet32 and thepump outlet34 to alternate between the open and closed states.
• Referring particularly to FIGS.[0105]14A-14B, theactuator102 is disclosed in greater detail. Theactuator102 includes abase portion104 and at least oneengagement arm106 extending from thebase portion104. The at least oneengagement arm106 of theactuator102 operatively engages thepump assembly28 to retain thepump inlet32 and thepump outlet34 in the open state during sterilization. In the preferred embodiment of the subject invention, theactuator102 more specifically includes first andsecond engagement arms108,110, respectively, extending from thebase portion104. In the preferred embodiment, theactuator102 also includes anactuation arm112. Theactuation arm112 extends from thebase portion104 between the first andsecond engagement arms108,110. As shown in the Figures, theactuation arm112 extends upwardly from thebase portion104 between the first andsecond engagement arms108,110.
• During sterilization, the[0106]first engagement arm108 of theactuator102 engages thefirst pinch lever38 to move thefirst pinch lever38 away from thepump inlet32 to retain thepump inlet32 in the open state. Similarly, during sterilization, thesecond engagement arm110 of theactuator102 engages thesecond pinch lever40 to move thesecond pinch lever40 away from thepump outlet34 to retain thepump outlet34 in the open state.
• After sterilization it is desirable to move the[0107]actuator102 into the disengaged position such that thepump assembly28 can operate and the medication can be delivered to thepatient12. As indicated by the arrow (A) in FIG. 6D, theplunger100 moves to displace the actuator102 from the engaged position thereby moving theactuator102 into the disengaged position. To displace theactuator102, theplunger100 engages theactuation arm112. Theplunger100 displaces the actuator102 from the operative engagement with thepump assembly28 after sterilization such that thepump inlet32 and thepump outlet34 can alternate between the open and the closed state to deliver the medication to thepatient12. More specifically, theplunger100 displaces the actuator102 from the engagement with the first and second pinch levers38,40 after sterilization such that medication can be delivered to thepatient12. As such, themotor42, which is operatively engaged to the first and second pinch levers38,40, can move theselevers38,40 for drawing the medication into thepump housing30 through thepump inlet32 and for displacing the medication from thepump housing30 through thepump outlet34.
• Referring now to FIG. 14B, a[0108]control contact114, preferably a spring-like control contact114, may be disposed at adistal end116 of theactuation arm112 away from thebase portion104 to indicate to thesystem10 whether theactuator102 is in the engaged or the disengaged position. Thecontrol contact114 interacts with theactuation arm112 of theactuator102 upon the movement of theactuator102 between the engaged or the disengaged position. If thecontrol contact114 is included, it is preferred that when theactuator102 is disengaged from the first and second pinch levers38,40, i.e., when theactuator102 is in the disengaged position, it contacts thecontrol contact114 to active anelectronic controller118. Theelectronic controller118 is activated to permit thepump assembly28 to operate for delivering the medication to thepatient12. As indicated above, it is preferred that theactuation arm112 of theactuator102 is in contact with thecontrol contact114 when theactuator102 is in the disengaged position. Of course, it is to be understood that the opposite could be true. That is, thesystem10 can be designed such that theactuation arm112 of theactuator102 is in contact with thecontrol contact114 when theactuator102 is in the engaged position.
• The[0109]system10 further includes amedication inlet tube120 and amedication outlet tube122. Themedication inlet tube120 is connected between theport82 and thepump inlet32 to provide access for the sterilization fluid to flow from theport82 into thepump assembly28, specifically into thepump inlet32. Themedication outlet tube122 is connected between thepump outlet34 and theport82 to provide access for the sterilization fluid to flow from thepump assembly28, specifically from thepump outlet34, into theport82. Themedication inlet tube120 and thefirst pinch lever38 together establish thepump inlet32, and themedication outlet tube122 and thesecond pinch lever40 together establish thepump outlet34.
• When the at least one[0110]biasing device44 engages thefirst pinch lever38 to normally-bias thefirst pinch lever38 into the closed position, themedication inlet tube120 is pinched. As such, thepump inlet32 is maintained in the closed state. Similarly, when the at least onebiasing device44 engages thesecond pinch lever40 to normally-bias thesecond pinch lever40 into the closed position, themedication outlet tube122 is pinched. As such, thepump outlet34 is maintained in the closed state. However, as disclosed in FIG. 6D, when theactuator102 is in the engaged position during sterilization, theactuator42 overcomes the bias of the at least onebiasing device44 to move thefirst pinch lever38 away from themedication inlet tube120 such that thepump inlet32 remains in the open state, and theactuator102 overcomes the bias of the at least onebiasing device44 to move thesecond pinch lever40 away from themedication outlet tube122 such that thepump outlet34 remains in the open state.
• Referring particularly to FIGS.[0111]3, and8-10, theport82 and theplunger100 are described in greater detail. Theplunger100 includes a length L, a circumference C, and a plurality ofseats124 disposed along the length L and about the circumference C of theplunger100. Theseats124 extend outwardly from the circumference C of theplunger100 to theinterior wall90 of theelongated housing84 of theport82 to segregate thefluid chamber92 of theelongated housing84. A fluid passage, not numbered, is defined between each of theseats124 and theinterior wall90 of the housing. These fluid passages control the flow of fluid within theport82. Although theseats124 may suitably segregate thefluid chamber92, it is preferred thatseals126 are disposed about each of theseats126 to assist with sealing the fluid passages from one another. In the most preferred embodiment, which is shown in the Figures, these seals are O-rings. At least oneleak rib128 extends at least partially along theinterior wall90 of theelongated housing84. The at least oneleak rib128 selectively causes at least one of theseals126 to leak when theplunger100 is in the fill-position. As disclosed in the Figures, preferably there are twoleak ribs128 that extend along theinterior wall90 of theelongated housing84.
• As shown in FIGS.[0112]11A-13B, theplunger100 is at least partially hollow. As such, theplunger100 defines an internal fluid bore130 that extends within theplunger100 between theseats124. Theplunger100 further includes anaccess end132 and aplunger actuation end134. Aplunger biasing device136, preferably a compression spring, is disposed about theplunger actuation end134 of theplunger100 to bias theplunger100 into the off-position. The internal fluid bore130 extends from theaccess end132, where the fluid flows into and from the internal fluid bore130, toward theplunger actuation end134. The internal fluid bore130 includes afluid duct138 in fluid communication with one of the fluid passages such that the flow can flow into and from the internal fluid bore130.
• In the most preferred embodiment of the subject invention, the plurality of[0113]seats124 are further defined as a first, second, third, andfourth seat140,142,144,146, respectively. Thefirst seat140 is disposed toward the access end132 of theplunger100, thefourth seat146 is disposed toward theplunger actuation end134 of theplunger100, and the second andthird seats142,144 are disposed successively between the first andfourth seats140,146. In this embodiment, the fluid passages are further defined as a first, second, and thirdfluid passage148,150,152, respectively. Thefirst fluid passage148 is defined between the first andsecond seats140,142 and theinterior wall90, thesecond fluid passage150 is defined between the second andthird seats142,144 and theinterior wall90, and thethird fluid passage152 is defined between the third andfourth seats144,146 and theinterior wall90.
• A[0114]first seal154 is disposed about thefirst seat140 for sealing thefirst fluid passage148 from the access end132 of theplunger100, asecond seal156 is disposed about thesecond seat142 for sealing the first and secondfluid passages148,150 from one another, athird seal158 is disposed about thethird seat144 for sealing the second and thirdfluid passages150,152 from one another, and afourth seal160 is disposed about thefourth seat146 for sealing thethird fluid passage152 from theplunger actuation end134 of theplunger100. In this embodiment, the at least oneleak rib128 extends along theinterior wall90 of theelongated housing84 from theproximate end86 toward thedistal end88 just beyond thefirst seal154 such that only thefirst seal154 selectively leaks when theplunger100 is in the fill-position.
• In this most preferred embodiment, the internal fluid bore[0115]130 extends within theplunger100 from theaccess end132 to thethird seat144. As such, thefluid duct138 is in fluid communication with thesecond fluid passage150 defined between the second andthird seats142,144 and theinterior wall90 such that the fluid can flow into and from the internal fluid bore130 at thesecond fluid passage150.
• The off-, fill-, and fluid delivery-positions of the[0116]plunger100 are now described in the context of this most preferred embodiment having fourseats140,142,144,146, threefluid passages148,150,152, and fourseals154,156,158,160. Referring to FIGS.11A-11B, when theplunger100 is in the off-position, the first, second, and thirdfluid connectors94,96,98 are isolated from theproximate end86 of theelongated housing84 and from the access end132 of theplunger100 by the first, second, andthird seats140,142,144. In this off-position, the first and thirdfluid connectors94,98 are aligned with thethird fluid passage152.
• Referring to FIGS.[0117]12A-12B, when theplunger100 is in the fill-position, the first and thirdfluid connectors94,98 are in fluid communication with theproximate end86 of theelongated housing84 and with the access end132 of theplunger100 through thesecond fluid passage150 and thefluid duct138 of the internal fluid bore130. In this fill-position, the first and thirdfluid connectors94,98 are aligned with thesecond fluid passage150. As such, the fluid can be filled through the access end132 of theplunger100, through the internal fluid bore130 and thefluid duct138, and into thereservoir24 and thepump assembly28. In the fill-position, thesecond fluid connector96 is isolated from theproximate end86 of theelongated housing84, from the access end132 of theplunger100, and from the first and thirdfluid connectors94,98 by the third andfourth seats144,146.
• Referring to FIGS.[0118]13A-13B, when theplunger100 is in the fluid delivery-position, thesecond fluid connector96 is in fluid communication with theproximate end86 of the housing and with the access end132 of theplunger100 through saidsecond fluid passage150 and thefluid duct138 of the internal fluid bore130. In the fluid delivery-position, the medication is delivered from thepump assembly28 to thepatient12. In the fluid delivery-position, the first and thirdfluid connectors94,98 are isolated from theproximate end86 of the housing and from the access end132 of theplunger100 by the first andsecond seats140,142. However, the first and thirdfluid connectors94,98 are in fluid communication with thereservoir24 through thefirst fluid passage148 to supply thepump assembly28 with the fluid, i.e., with the medication. That is, in the fluid delivery-position, the first and thirdfluid connectors94,98 are aligned with thefirst fluid passage148.
• A fluid filling device, shown generally in FIG. 12B at[0119]162, engages theproximate end86 of the housing to automatically move theplunger100 into the fill-position for filling thereservoir24 and thepump assembly28. If thesystem10 is being sterilized, then thefluid filling device162 is preferably a fluid, or sterilization, cap164 (shown detached from thesystem10 in FIG. 12B) that moves theplunger100 into the fill-position to enable a sterilization fluid to penetrate into thereservoir24 and thepump assembly28. Thefluid cap164, by design, automatically moves theplunger100 into the fill-position. Therefore, when thesystem10 is introduced into a chamber filled with the sterilization fluid, preferably EtO gas, then the sterilization fluid flows, or seeps, through thefluid cap164, through theproximate end86 of theelongated housing84 and the access end132 of theplunger100, through the internal fluid bore130 and thefluid duct138, into thesecond fluid passage150, through the thirdfluid connector98 into thereservoir24, and through thefirst fluid connector94 into thepump assembly28.
• If the[0120]system10 is being filled with medication, then thefluid filling device162 is preferably asyringe166 that moves theplunger100 into the fill-position for filling thereservoir24 and thepump assembly28. The syringe166 (shown attached to thesystem10 in FIG. 12B) engages the access end132 of theplunger100 and, by design, automatically moves theplunger100 into the fill-position for filling thereservoir24 and thepump assembly28 through the internal fluid bore130. Therefore, when thesystem10 is being filled, thesyringe166 interacts with theproximate end86 of theelongated housing84 and the access end132 of theplunger100 and, as the syringe plunger is depressed, the medication flows through the internal fluid bore130 and thefluid duct138, into thesecond fluid passage150, through the thirdfluid connector98 into thereservoir24, and through thefirst fluid connector94 into thepump assembly28.
• To deliver the medication to the[0121]patient12, thesystem10 is utilized in combination with the infusion tube set14. Referring back to FIG. 1A, the infusion tube set14 includes afluid end168 and apatient end170. Thefluid end168 of the tube set14, through adelivery connector172, engages theproximate end86 of theelongated housing84 and the access end132 of theplunger100 to automatically move theplunger100 into the fluid delivery-position for delivering the medication to thepatient12. Therefore, as shown in FIGS.13A-13B, when thepump assembly28 is operating, the medication is drawn from thereservoir24 through the thirdfluid connector98 into theport82 at thefirst fluid passage148, and through thefirst fluid connector94 into thepump inlet32. The medication is then displaced out of thepump assembly28 through thepump outlet34, through thesecond fluid connector96 into theport82 at thesecond fluid passage150, through thefluid duct138 and the internal fluid bore130 of theplunger100, and out the access end132 of theplunger100 at thefluid end168 of the infusion tube set14. From there, the medication flows through the infusion tube set14, out thepatient end170, and to thepatient12.
• Referring back to FIG. 4, the[0122]system10 further includes theelectronic controller118. Theelectronic controller118 controls an amount of the medication that is to be delivered to thepatient12. Theelectronic controller118 is mounted to thebase housing16, specifically to thetop housing22 of thebase housing16. Furthermore, theelectronic controller118 remains mounted to thebase housing16 during sterilization such that theentire system10, including all mechanical components, thereservoir24, and theelectronic controller118, is simultaneously sterilized. Anelectronic display174 and at least onecontrol button176 are mounted to thebase housing16. Theelectronic display174 and thecontrol button176 interact with theelectronic controller118 to control the amount of the medication to be delivered to thepatient12. As with theelectronic controller118, theelectronic display174 and thecontrol button176 also remain mounted to thebase housing16 during sterilization.
• The subject invention also provides a blockage detection system which is generally disclosed at[0123]178 in FIGS.15A-15B. Theblockage detection system178 detects a blockage in the flow of the medication to thepatient12. Theblockage detection system178 comprises thebase housing16, thereservoir24, theport82, thepump assembly28, themedication outlet tube122, and theelectronic controller118. Theblockage detection system178 also includes adetection film180 which is described below.
• In the[0124]blockage detection system178, theelectronic controller118 is mounted to thebase housing16 adjacent theoutlet tube122. Theoutlet tube122 is mounted to thebase housing16 and, as described above, is connected between thepump assembly28 and theport82 to provide access for the medication to flow from thepump assembly28 into theport82 and to thepatient12. Theoutlet tube122 has a diameter that is contractible and expandable between a normal condition (see FIG. 15A) and an expanded condition (see FIG. 15B). The diameter of theoutlet tube122 contracts and expands in response to variations in pressure that result from the flow of the medication from thereservoir24 through thepump assembly28 into theport82 and to thepatient12.
• As disclosed in the Figures, the[0125]outlet tube122 is mounted to thebase housing16 via asupport platform182. That is, thesupport platform182 is mounted on thebase housing16 to support theoutlet tube122 on thebase housing16. Thesupport platform182 includes at least onetube slot184. The at least onetube slot184 houses the diameter of theoutlet tube122. Theoutlet tube122 is mounted in thetube slot184 such that at least a portion, not numbered, of the diameter of theoutlet tube122 is exposed to thedetection film180.
• The[0126]detection film180 is disposed between theelectronic controller118 and theoutlet tube122. Thedetection film180 is in contact with theoutlet tube122 and remains spaced from theelectronic controller118 when the diameter of theoutlet tube122 is in the normal condition, as in FIG. 15A. On the other hand, thedetection film180 is in contact with theoutlet tube122 and contacts theelectronic controller118 to activate theelectronic controller118 when the diameter of theoutlet tube122 is in the expanded condition, as in FIG. 15B, in response to increased pressure resulting from the blockage in the flow of the medication to thepatient12. More specifically, it is preferred that anelectronic switch186 is embedded in theelectronic controller118 between theelectronic controller118 and thedetection film180. Thedetection film180 interacts with theelectronic controller118 by contacting theelectronic switch186 to activate theelectronic controller118 when the diameter of theoutlet tube122 is in the expanded condition.
• For activating the[0127]electronic controller118 when the diameter of theoutlet tube122 is in the expanded condition, it is also preferred that thedetection film180 is conductive. Once activated by thedetection film180, theelectronic controller118 deactivates thepump assembly28 to prevent delivery of the medication to the patient12 when the diameter of theoutlet tube122 is in the expanded condition. Deactivation of thepump assembly28 prevents further blockage and further increases in pressure. To properly ensure that the there is a blockage in theoutlet tube122, it is most preferred that theelectronic controller118, and therefore thepump assembly28, are deactivated only if the diameter of theoutlet tube122 is in the expanded condition for more than at least one cycle of thepump assembly28. This additional measure avoids false readings and the deactivation of thepump assembly28 when theoutlet tube122 is truly not blocked.
• Additionally, once activated by the[0128]detection film180, theelectronic controller118 may also activate analarm188, shown schematically in the Figures. Thealarm188, which can be audible and/or visually displayed on theelectronic display174, would indicate the blockage that is due to the blockage in the flow of the medication to thepatient12.
• It is preferred that the[0129]detection film180 is mounted to theelectronic controller118. Although thedetection film180 is mounted to theelectronic controller118, a portion, not numbered, of thedetection film180 remains at least partially-spaced from theelectronic controller118 when the diameter of theoutlet tube122 is in the normal condition. Thedetection film180 is mounted to theelectronic controller118 with anadhesive layer190. Theadhesive layer190 also establishes a thickness that is necessary to space thedetection film180, specifically the portion of thedetection film180, from theelectronic controller118 when the diameter of theoutlet tube122 is in the normal condition. The portion of thedetection film180 contacts theelectronic controller118 to activate theelectronic controller118 when the diameter of theoutlet tube122 is in the expanded condition in response to increased pressure in theoutlet tube122.
• An alternative embodiment for the[0130]blockage detection system178 is disclosed in FIG. 17. In this alternative embodiment, thedetection film180 is eliminated, and acoating192 is included. Thecoating192 is applied to theoutlet tube122. Thecoating192 activates theelectronic controller118 when the diameter of theoutlet tube122 is in the expanded condition in response to increased pressure resulting from the blockage in the flow of the medication to thepatient12. As with thedetection film180, thecoating192 is preferably conductive. If thecoating192 is present, it is most preferred that thecoating192 is formed of conductive carbon. However, other coatings may be used that impart conductive properties to thecoating192.
• For the most part, the other characteristics of this alternative embodiment for the[0131]blockage detection system178 are identical to the characteristics that were described above in the preferred embodiment for theblockage detection system178. Notably, theoutlet tube122 is mounted in thetube slot184 in this alternative embodiment such that at least a portion of thecoating192 is exposed beyond thetube slot184.
• The subject invention also provides an empty detection system which is generally disclosed at[0132]194 in FIGS.16A-16B. Theempty detection system194 determines when a supply of the medication has been depleted. Theempty detection system194 comprises thebase housing16, thereservoir24 for storing the supply of the medication to be delivered to thepatient12, theport82, thepump assembly28, themedication inlet tube120, and theelectronic controller118. As with theblockage detection system178, the preferred embodiment of theempty detection system194 also includes a detection film, also numbered180, which is described below.
• In the[0133]empty detection system194, theelectronic controller118 is mounted to thebase housing16 adjacent theinlet tube120. Theinlet tube120 is mounted to thebase housing16 and, as described above, is connected between thereservoir24 and thepump assembly28 to provide access for the medication to flow from thereservoir24 into thepump assembly28 and to thepatient12. Theinlet tube120 has a diameter that is contractible and expandable between a normal condition (see FIG. 16A) and a collapsed condition (see FIG. 16B). Theinlet tube120 contracts into the collapsed condition and expands from the collapsed condition into the normal condition. The diameter of theinlet tube120 contracts and expands in response to variations in pressure that result from a lack of the flow of the medication from thereservoir24 through thepump assembly28 and to thepatient12.
• As disclosed in the Figures, the[0134]inlet tube120 is mounted to thebase housing16 via thesupport platform182. That is, thesupport platform182 is mounted on thebase housing16 to support theinlet tube120 on thebase housing16. Thesupport platform182 includes the at least onetube slot184. The at least onetube slot184 houses the diameter of theinlet tube120. Theinlet tube120 is mounted in thetube slot184 such that at least a portion of the diameter of theinlet tube120 is exposed to thedetection film180.
• The[0135]detection film180 is disposed between theelectronic controller118 and theinlet tube120. As shown in FIG. 16A, thedetection film180 is in contact with theinlet tube120 and contacts theelectronic controller118 to activate theelectronic controller118 when the diameter of theinlet tube120 is in the normal condition. On the other hand, as shown in FIG. 16B, thedetection film180 becomes spaced from theelectronic controller118 to deactivate theelectronic controller118 when the diameter of theinlet tube120 is in the collapsed condition in response to the lack of flow of the medication that results from the supply of the medication being depleted.
• It is preferred that an[0136]electronic switch186 is embedded in theelectronic controller118 between theelectronic controller118 and thedetection film180. Thedetection film180 contacts theelectronic switch186 to activate theelectronic controller118 when the diameter of theinlet tube120 is in the normal condition, and thedetection film180 becomes spaced from theelectronic switch186 to deactivate theelectronic controller118 when the diameter of theinlet tube120 is in the collapsed condition.
• As best disclosed in FIG. 4, the[0137]detection film180 more specifically includes afilm base portion196 and acantilever portion198. Thefilm base portion196 of thedetection film180 is mounted to theelectronic controller118 away from theelectronic switch186, and thecantilever portion198 of thedetection film180 is adjacent theelectronic switch186. More specifically, thecantilever portion198 extends from thefilm base portion104 to contact theelectronic switch186 when the diameter of theinlet tube120 is in the normal condition. It is thecantilever portion198 of thedetection film180 that becomes spaced from theelectronic controller118 to deactivate theelectronic controller118 when the diameter of theinlet tube120 is in the collapsed condition. For activating theelectronic controller118 when the diameter of theinlet tube120 is in the normal condition, it is also preferred that thedetection film180, specifically thecantilever portion198 of thedetection film180, is conductive. Preferably, thedetection film180 is mounted to theelectronic controller118 with anadhesive layer190. Of course, it is thefilm base portion196 of thedetection film180 that is directly mounted to theelectronic controller118. Thecantilever portion198 of thedetection film180 is not directly mounted, or otherwise adhered, to theelectronic controller118 such that this portion of thedetection film180 can become spaced from theelectronic controller118 when the diameter of theinlet tube120 is in the collapsed condition.
• Once the[0138]detection film180 becomes spaced from theelectronic controller118, i.e., when the diameter of theinlet tube120 is in the collapsed condition, the portion of theelectronic controller118 that interacts with thepump assembly28 is deactivated such that thepump assembly28 is deactivated. Deactivation of thepump assembly28 after it has been determined that the supply of the medication has been depleted prevents a build up of air in the system. To properly ensure that the supply of the medication has been depleted, it is most preferred that theelectronic controller118, and therefore thepump assembly28, are deactivated only if the diameter of theinlet tube120 is in the collapsed condition for more than at least one cycle of thepump assembly28. This additional measure avoids false readings and the deactivation of thepump assembly28 when the supply of the medication is truly not depleted.
• Additionally, deactivation of the portion of the[0139]electronic controller118 that interacts with thepump assembly28 may also cause theelectronic controller118 to activate thealarm188. Thealarm188, which can be audible and/or visually displayed on theelectronic display174, would indicate the lack of flow of the medication when the diameter of theinlet tube120 is in the collapsed condition due to the lack of flow of the medication to thepatient12.
• An alternative embodiment for the[0140]empty detection system194 is disclosed in FIG. 17. In this alternative embodiment, thedetection film180 is eliminated, and thecoating192 is included. Thecoating192 is applied to theinlet tube120. Thecoating192 contacts theelectronic controller118 to activate theelectronic controller118 when the diameter of theinlet tube120 is in the normal condition. On the other hand, thecoating192 becomes spaced from theelectronic controller118 to deactivate theelectronic controller118 when the diameter of theinlet tube120 is in the collapsed condition in response to the lack of flow of the medication resulting from the supply of the medication being depleted. As with thedetection film180, thecoating192 is preferably conductive. If thecoating192 is present, it is most preferred that thecoating192 is formed of conductive carbon. However, other coatings may be used that impart conductive properties to thecoating192.
• For the most part, the other characteristics of this alternative embodiment for the[0141]empty detection system194 are identical to the characteristics that were described above in the preferred embodiment for theempty detection system194. Notably, theinlet tube120 is mounted in thetube slot184 in this alternative embodiment such that at least a portion of thecoating192 is exposed beyond thetube slot184.
• Referring now to FIGS.[0142]1B,6A-6D, and18A-18B, thesystem10 of the subject invention can be tested using atesting instrument200 after assembly of thesystem10. Thesystem10 is tested after assembly and prior to shipment and use by the surgeons, patients, and the like to confirm various operations of thesystem10. In the preferred embodiment, to test thesystem10, thesystem10 is mounted onto thetesting instrument200. One operation of thesystem10 that is confirmed after assembly of thesystem10 is the operation of thepump assembly28.
• To confirm these operations, the[0143]system10 includes at least onetesting access port202. The at least onetesting access port202 is defined within thebase housing16 and is aligned with at least one of thepump inlet32, thepump outlet34, and theactuator102. Preferably, the at least onetesting access port202 is aligned with all three of thepump inlet32, thepump outlet34, and theactuator102. The at least onetesting access port202 provides access for thetesting instrument200 to move theactuator102 between the disengaged position and the engaged position. If the at least onetesting access port202 is aligned with thepump inlet32 and thepump outlet34 then it is aligned with the first and second pinch levers38,40, respectively. Also, as for the alignment with theactuator102, the at least onetesting access port202 is more specifically aligned with the at least oneengagement arm106 of theactuator102. This provides access for thetesting instrument200 to move theactuator102 between the disengaged position and the engaged position.
• The[0144]system10 is preferably assembled with theactuator102 in the engaged position such that the first and second pinch levers38,40 are in the open position and the resiliency and life of the medication inlet andoutlet tubes120,122 is not compromised. Because the at least onetesting access port202 provides access for thetesting instrument200 to move theactuator102 between the disengaged position and the engaged position, thetesting instrument200 can be inserted into the at least onetesting access port202 to disengage theactuator102, i.e., to move theactuator102 into the disengaged position. As such, thepump inlet32 and thepump outlet34 can alternate between the open and closed states after assembly and during testing of thesystem10.
• The at least one testing access port also provides access for the[0145]testing instrument200 such that thepump inlet32 and thepump outlet34 can be retained in the open state after thesystem10 has been tested to prepare thesystem10 for sterilization. That is, after thesystem10 has been tested, theactuator102 is moved from the disengaged position back into the engaged position to prepare thesystem10 for sterilization. In the engaged position, the first and second pinch levers38,40 are retained in the open state.
• In the preferred embodiment, the at least one[0146]testing access port202 is further defined as first, second, and thirdtesting access ports204,206,208, respectively. The firsttesting access port204 is aligned with thepump inlet32, the secondtesting access port206 is aligned with thepump outlet34, and the thirdtesting access port208 is aligned with theactuator102 for providing access to thetesting instrument200 to move theactuator102 into the engaged position. More specifically, the firsttesting access port204 is aligned with thefirst pinch lever38 such that thefirst pinch lever38 is engaged by thetesting instrument200. Once inside the firsttesting access port204, thetesting instrument200 forces thefirst pinch lever38 away from thepump inlet32 and forces thepump inlet32 into the open state. Similarly, the secondtesting access port206 is aligned with thesecond pinch lever40 such that thesecond pinch lever40 is engaged by thetesting instrument200. Once inside the secondtesting access port206, thetesting instrument200 forces thesecond pinch lever40 away from thepump outlet34 and forces thepump outlet34 into the open state. The first and second pinch levers38,40 include the lever guides78 opposite thecam follower76 of eachpinch lever38,40. To move the first and second pinch levers38,40, thetesting instrument200 engages the lever guides78 upon insertion into the first and secondtesting access ports204,206. After thetesting instrument200 forces the first and second pinch levers38,40 away from thepump inlet32 and thepump outlet34, respectively, thetesting instrument200 is introduced into the thirdtesting access port208 and theactuator102 is moved into the engaged position to engage and retain the pinch levers38,40 in the open position such that thesystem10 is now prepared for sterilization. It is to be understood by those skilled in the art that thetesting instrument200 includes male prongs, generally indicated at210, that are introduced into thetesting access ports204,206,208.
• The[0147]system10 further includes at least onecontroller access port212 defined within thebase housing16. In the preferred embodiment, the at least onecontroller access port212 is defined within thetop housing22 or cover. The at least onecontroller access port212 is aligned with theelectronic controller118 to provide access for asecond testing instrument214. It is to be understood that thesecond testing instrument214 and thetesting instrument200 may be a unitary component, as disclosed in the Figures. Thesecond testing instrument214 causes theelectronic controller118 to activate themotor42 such that themotor42 is powered to alternate thepump inlet32 and thepump outlet34 between the open and closed states after assembly and during testing of thesystem10. Thesecond testing instrument214 also preferably includesmale prongs210 that are introduced into thecontroller access ports212.
• Referring primarily to FIGS.[0148]2A-3, and19-20, thesystem10 of the subject invention is also suitable to be carried by thepatient12. To facilitate carrying of thesystem10 so the patient12 can remain ambulatory, a carryingstrap216 is mounted within thebase housing16 for the carrying of thesystem10 by thepatient12. Anintegral storage cavity218 is defined within thebase housing16. The carryingstrap216 is at least partially disposed in theintegral storage cavity218. The carryingstrap216 at least partially extends from theintegral storage cavity218 to interact with thepatient12 for carrying thesystem10.
• The[0149]system10 further includes a plurality of cavity walls. The cavity walls extend from thebottom housing18 to define theintegral storage cavity218 between the bottom18 and top22 housings. Referring particularly to FIG. 20, the cavity walls are further defined as afront wall220, arear wall222, and first andsecond side walls224 extending between the front andrear walls220,222 to support the front andrear walls220,222 and to define theintegral storage cavity218. At least onestrap slot226 is defined within thefront wall220 such that at least a portion, not numbered, of the carryingstrap216 extends from theintegral storage cavity218 and through thestrap slot226. The patient12 can then access the portion of the carryingstrap216 when desired.
• In interacting with the carrying[0150]strap216, the patient12 simply manipulates, or grabs, the portion of the carryingstrap216 to pull a length of the carryingstrap216 from theintegral storage cavity218. This length is then looped about the head of the patient12 as specifically disclosed in FIG. 19. In the preferred embodiment, the carryingstrap216 is retractable into theintegral storage cavity218 after the length has been pulled from theintegral storage cavity218 by thepatient12. Thesystem10 further includes aclip228 that connects opposing ends of the carryingstrap216 such that the carryingstrap216 is adjustable to fitpatients12 of all sizes. In the most preferred embodiment of the subject invention, which is disclosed in FIG. 19, the carryingstrap216 is further defined as a shoulder strap. The shoulder strap suspends from a shoulder of thepatient12 for carrying thesystem10.
• Also, as particularly disclosed in FIG. 1B, the[0151]system10 may also further include asystem mounting clip230 that extends from an exterior facing232 of thebase housing16. Thesystem mounting clip230 can be mounted to abelt234 of thepatient12. Of course, it is to be understood that thesystem mounting clip230 is not to be limited to a clip for abelt234. Instead, thesystem mounting clip230 may be mounted to a shirt, a pocket, and the like.
• Referring to FIGS.[0152]2B, and21-24, the subject invention further provides a method of controlling thesystem10. This method is designed to be convenient for both the surgeon, or other medical professional, and thepatient12. Apatient label236, having a second set of explanatory indicia, i.e., instructions, is mounted, preferably adhered, to thesystem10. Aremovable overlay label238, having a first set of explanatory indicia, i.e., instructions, is mounted, preferably adhered, to thepatient label236 to at least partially cover thepatient label236.
• The method includes the steps of selecting the amount of the medication in accordance with the first set of explanatory indicia on the[0153]removable overlay label238. The medical professional selects the amount of the medication. As such, the first set of explanatory indicia is intended to be readily understood by the medical professional. Typically, the amount of the medication is selected by selecting the flow rate for the medication. Other parameters including, but not limited to, the bolus amount, the drug or medication concentration, and like, can also be selected.
• Throughout the step of selecting, the medical professional and/or[0154]patient12 interfaces with theelectronic display174 to view his or her selections. More specifically, theelectronic display174 presents a readable output for the medical professional and thepatient12. The readable output displayed on theelectronic display174 is correlated with theremovable overlay label238 and thepatient label236. That is, the readable output is correlated to the first and second sets of instructions. A first readable output is presented on theelectronic display174. The first readable output is linked with the first set of explanatory indicia when theremovable overlay label238 is displayed. Similarly, a second readable output is presented on theelectronic display174. The second readable output is linked with the second set of explanatory indicia after thesystem10 has been locked. Locking thesystem10 is described immediately below.
• After the amount of the medication has been selected, the[0155]system10 is locked such that selected amount of the medication to be delivered to thepatient12 is unable to be modified. After the medical professional is satisfied with his or her selection, the medical professional depresses the “LOCK” portion of the first set of explanatory indicia on theremovable overlay label238 to lock thesystem10.
• Once the[0156]system10 is locked, either the medical professional or the patient12 can remove theremovable overlay label238 to reveal the patient label236 (as shown in FIG. 21). To accomplish this, the user, either the medical professional or thepatient12, simply pulls theremovable overlay label238 off thepatient label236. This reveals thecontrol button176 that was originally masked under theremovable overlay label238. Thesystem10 is then operated in accordance with a second set of explanatory indicia on thepatient label236. The second set of explanatory indicia is intended to be readily understood by thepatient12. Once thesystem10 is locked, thesystem10 is designed to be convenient for use by thepatient12.
• Upon locking the[0157]system10, a functionality of thecontrol button176 is modified. As such, the functionality of thecontrol button176 is different when theremovable overlay label238 is displayed on thesystem10 as compared to when thepatient label236 is displayed on thesystem10. In other words, the functionality of thecontrol button176 is different when the medical professional interacts with thesystem10 via theremovable overlay label238 as compared to when thepatient12 interacts with thesystem10 via thepatient label236. When theremovable overlay label238 is displayed on thesystem10, thecontrol button176 is at least tri-functional. On the other hand, after thesystem10 has been locked and thepatient label236 is displayed on thesystem10, the functionality of thecontrol button176 is converted from being at least tri-functional to being bi-functional.
• In operating the[0158]system10, thesystem10 may be deactivated, if necessary, to stop delivery of the medication to thepatient12. To deactivate thesystem10, thepatient12 depresses the “ON/OFF” portion of the, now bi-functional,control button176 in response to the second set of explanatory indicia on thepatient label236. If thesystem10 is deactivated, then the patient12 may also use thecontrol button176 to activate thesystem10 to re-start delivery of the medication to thepatient12. To accomplish this, thepatient12 depresses the “ON/OFF” portion of thecontrol button176 again.
• Alternatively, in operating the[0159]system10, thepatient12 may request an additional amount of the medication relative to the selected amount of the medication, and provided the Bolus amount will not be violated, thepatient12 will receive an additional amount of the medication. To request an additional amount of the medication relative to the selected amount, the patient12 actuates thecontrol button176.
• With specific reference to FIG. 25, a[0160]control system240 for thesystem10, according to an embodiment of the present invention is shown. Thecontrol system240 includes theelectronic controller118 and amotor control circuit242. Theelectronic controller118 controls operation of thesystem10 as described above.
• In one embodiment, the[0161]electronic controller118 includes amicroprocessor244. Onesuitable microprocessor244 is available from Philips Semiconductor of Sunnyvale, Calif. as model no. 87LPC764. Theelectronic controller118 is programmed to control operation of themotor control circuit242 with a computer software program. In general, theelectronic controller118 generates control signals in accordance with the computer software program and delivers the control signals to themotor control circuit242.
• The[0162]motor control circuit242 includes afirst switch246. Thefirst switch246 has an open state and a closed state.
• The[0163]control system240 also includes awatchdog circuit248 coupled to theelectronic controller118. Thewatchdog circuit248 includes amonitor circuit250 and asecond switch252. Thesecond switch252 has an open state and a closed state and is coupled to thefirst switch246. Themonitor circuit250 is adapted to detect an abnormal condition of thecontrol system240 and to turn thesecond switch252 off if the abnormal condition is detected. Examples of an abnormal condition include, but are not limited to, too many revolutions of themotor42, failure of theelectronic controller118, failure of thefirst switch246, or failure of a motor sensor254 (see below).
• The[0164]motor control circuit242 is adapted to receive control signals from theelectronic controller118 and to responsively supply power to themotor42 by placing thefirst switch246 in the closed state. Power is supplied to themotor42 if the first andsecond switches246,252 are in the closed state.
• With reference to FIGS. 26 and 27, in one embodiment the first and[0165]second switches246,252 are field effect transistors (FETs)256,258. In one embodiment, thecontrol system240 includes thecontrol buttons176. A user such as the surgeon or thepatient12 is able to program thecontrol system240 to deliver medication at the desired flow rate. Based on the desired flow rate, theelectronic controller118 controls energization of themotor42 to deliver the medication.
• In one embodiment, each revolution of the[0166]motor42 delivers a set amount of the medication during a known period of time. A predetermined number of revolutions of themotor42 delivers a “pulse” of medication. In order to meet the desired flow rate, theelectronic controller118 calculates a period of time between revolutions of themotor42.
• In one embodiment of the present invention, the period of time calculated by the controller[0167]118 (between pulses) is constant fixed for the desired flow rate.
• In one aspect of the present invention, the[0168]controller118 controls thepump assembly28 to provide a series of pulses of medication to provide the desired flow of medication. With reference to FIGS. 28, 29A,29B, and29C, the fluid flow output of thesystem10 may be subdivided. As shown, the fluid flow from the tube set14 may be divided by aflow divider288 to provide fluid flow to a plurality oflegs290. In the illustrated embodiment, there are n legs each having a respective fluid flowrate of {dot over (M)}_n.
• In one embodiment, the series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce the effect of any differential pressure between the legs. In other words, a differential pressure across two legs, e.g.,[0169]Leg1 andLeg2, may result in a differential flow rate through each leg. Thecontroller118 manipulates the pulses to maintain the total pressure through the tube set14 high enough for a long enough period of time to reduce the effect of the differential pressure at the legs. For example, the pulses may be spaced together closely enough so that each pulse begins before a significant drop in fluid pressure level occurs following the previous pulse.
• With reference to FIG. 29A in another aspect of the present invention, the[0170]controller118 controls thepump assembly28 to providegroups292 of pulses. In one embodiment, the number of pulses in agroup292 is predetermined. For exemplary purposes only, first andsecond groups292A,292B are shown with eight pulses each. A first time period, t1, separates the start of each pulse within agroup292 and a second time period, t2, separates the start of each group. The first and second time periods may be determined by thecontroller118 to provide the desired flow rate while maintaining the desired flow through eachleg290 and reducing the effect of any pressure differential. For example, the number of pulses in eachgroup290 may be 10, the first time period may be equal to 1.8 seconds and the second time period may be 100 to 1300 seconds. Of course, the numbers are for explanation purposes only. The present invention is not limited to any such examples.
• In another embodiment, the first time period is fixed and the[0171]controller118 determines the second period as a function of the desired fluid flow.
• In another aspect of the present invention, a method for delivering medication using a[0172]medication delivery system10 including the steps of storing a supply of medication, receiving a desired flow of medication, and providing a flow of medication from the supply of medication in the form of a series of pulses. The flow is provided through an outlet and is subdivided into a plurality oflegs290. The series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce an effect of any differential pressure between the legs.
• Since a higher pulse frequency may lead to an average flow rate during pulsing that is higher than the desired flow rate, the pulses may be delivered in groups of a given number of pulses (see above); the time elapsing between each group may be set as a function of the overall time-averaged flow rate desired from the pump (see above). This grouping of pulses can negatively affect the flow distribution to the various sites because the final pulse in a group will conclude with an asymptotic pressure drain during which the flow balance degrades as the pressure drops. To compensate for this, a group size may be selected so that the amount of flow occurring during the steady-state period of intermittent pulsing will sufficiently reduce the effect of the imbalanced flow that happens subsequent to the final pulse. With reference to FIGS. 29B and 29C, a representative sketch of a pressure profile during a group of pulses is shown. Pcritical represents a pressure level above which acceptable flow distribution may be assured. This value is dependent upon the desired level of accuracy and the level of variation in the outlet pressures.[0173]
• The pump pulse method described above controls pressure and provides good flow splitting characteristics. In one embodiment of the present invention, the[0174]flow divider288 may be designed to, in conjunction with the pump pulse method described above, to provide back pressure assistance, anti-siphon characteristics, and controlled restriction.
• With reference to FIG. 29D, in one aspect of the present invention, the[0175]flow divider288 includes a valve system294 which provides flow restriction and anti-siphoning components to control flow split. In the illustrated embodiment, the valve system294 includes two legs each leading to anextended fenestration catheter296.
• As shown, in the illustrated embodiment, the infusion tube set[0176]14 includes apriming adapter294A, an on/offclamp294B, and afilter294C. A divider, shown as a Y-connector,294D is coupled to thefilter294C.
• Each leg of the infusion set[0177]14 after the Y-connector may include one or more low resistance, low crackingcheck valves294E. Thecheck valves294E alleviates the siphoning problems during inactivity of the pump assembly28 (see above).
• Although the pressure deteriorates nearly to zero after the last pulse in a group, the number of pulses and the spacing of the pulses in a group may be determined so that the average pressure is great enough to provide adequate distribution of flow to each leg (see FIG. 29B and discussion above).[0178]
• Each leg may also include a[0179]flow restrictor294F. In the illustrated embodiment, theflow restrictors294F are coupled to one of thecheck valves294E. The flow restrictors294F have an orifice (not shown) with a predetermined flow restriction value. The predetermined flow restriction value may be coordinated with the average flow rate during a group of pulses to keep the average pressure differential at a desired level for flow balance.
• With reference to FIGS.[0180]30-36, in another aspect of the present invention, the infusion tube set14 may include a multiplesite infusion apparatus310. The multiplesite infusion apparatus310 may be coupled to anoutput tube312 of thesystem10 to split the medication delivered from thedelivery system10 and deliver the medicine through first andsecond outlet passageways314A,314B. In the illustrated embodiment, theapparatus310 is shown as a twosite infusion apparatus310, however, it should be noted that the present invention may provide medicine to a plurality of sites.
• The[0181]apparatus310 includes avalve housing316. Thevalve housing316 includes afirst end318 and asecond end320. Thefirst end318 includes the first andsecond outlet passageways314A,314B.
• An[0182]end cap330 has aclosed end332 and anopen end334. Theend cap330 is coupled to thevalve housing316 at theopen end334. Aflexible diaphragm336 is coupled between theend cap330 and thevalve housing316 and is movable from a closed position to and an open position by the fluid energy of the pulse. Thesecond end320 of thevalve housing316 and theflexible diaphragm336 form apressure chamber322. Thevalve housing316 further includes aninlet passageway324. Theinlet passageway324 is coupled to thepressure chamber322. The first andsecond outlet passageways314A,314B are coupled to thepressure chamber322 by first andsecond outlet conduits328A,328B, respectively. Theflexible diaphragm336 seals thepressure chamber322 from the first andsecond outlet conduits328A,328B when theflexible diaphragm336 is in the closed position and opens the first andsecond outlet conduits328A,328B to thepressure chamber322 when theflexible diaphragm336 is in the open position.
• The[0183]valve housing316 also includes arouting passageway326 adjacent theinlet passage324. Therouting passageway326 allows the medication deliverysystem inlet tube312 to be secured within thevalve housing316. In one embodiment of the present invention, the end of theinlet tube312 coated with a solvent and inserted through the inlet ofpassageway324. Theinlet passageway324 and theoutput tube312 have an interference fit. The solvent bonds theinlet tube312 and theinlet passageway324.
• As shown, in one embodiment of the present invention, the[0184]open end334 of thecap330 has anouter perimeter338. Theouter perimeter338 includes aridge340. Thesecond end320 of thevalve housing316 includes adetent342 along itsouter perimeter344. Thedetent342 receives theridge340 which allows thevalve housing316 and theend cap330 to be snapped together.
• In another aspect of the present invention, the[0185]apparatus310 includes abiasing mechanism344 coupled between thecap330 and theflexible diaphragm336 for biasing theflexible diaphragm336 towards the closed position. In one embodiment of the present invention, thebiasing mechanism344 includes a biasingspring346. The biasingspring346 may be either tubular or conical.
• In another aspect of the present invention, a[0186]piston348 may be juxtaposed between the biasingspring346 and theflexible diaphragm336. In one embodiment, theflexible diaphragm336 includes apiston receiving aperture350 for receiving afirst end352 of thepiston348.
• As shown, in one embodiment, the[0187]piston348 is hollow and includes aspring receiving chamber354. Theend cap330 includes aspring positioning pin356. One end of thespring346 is seated within thespring receiving chamber354 and the other end is centered on thespring position pin356.
• In another aspect of the present invention, the[0188]apparatus310 includes first andsecond bushings358A,358B which are located within and have an interference fit with the first andsecond outlet passageway314A,314B. First andsecond restriction orifices360A,360B are positioned within and have an interference fit with the first andsecond bushings358A,358B, respectively. Flexible outlet tubes (not shown) are coupled to thepassageways314A,314B to deliver medication to the sites, as needed.
• In one aspect of the present invention, the inner diameter of the[0189]orifice360A,360B are relatively small, e.g., 0.001 to 0.005 inches with a small manufacturing tolerance. Theorifices360A,360B are dimensioned to provide a large resistance to the flow of medication relative to resistance provided by the flexible outlet tubes and the sites where the medication is delivered. This assists in controlling the back pressure and thus minimizing the risk of an unequal amount of medication to be delivered to the two sites.
• In another aspect of the present invention, the[0190]flexible diaphragm336 includes an integrally molded O-ring362 around itsouter perimeter364. The O-ring362 is press fit within acircular groove366 in thevalve housing316. Thevalve housing316 includes one or more air release apertures368 which allow air to escape thegroove366 as the O-ring362 is pressed into thegroove366. The O-ring362 and thegroove366 ensures that theouter perimeter364 is coupled to the valve housing, thereby forming thepressure chamber322.
• In operation, the medication delivery system delivers medication through the[0191]inlet tube312 in pulses. With reference to FIG. 35, when theflexible diaphragm336 is in the closed position, theflexible diaphragm336 creates a seal on the outlet valve seats. As fluid is pumped in, a pressure is created (Pinlet) within thepressure chamber322. With theflexible diaphragm336 in the closed position, no flow of medication is allowed from thepressure chamber322 to theoutput passageways314A,314B. Thus, while theflexible diaphragm336 is in the closed position, the pressure at theoutlet conduits328A,328B (Poutlet) is substantially zero.
• When the “pulse” of medication from the medication delivery system begins, Pinlet quickly ramps up from a non-zero value. When the force exerted by the pressurized medication within the[0192]pressure chamber322 on theflexible diaphragm336 is great enough to overcome the force exerted by thebiasing mechanism344, theflexible diaphragm336 is moved from the closed position towards the open position. After theflexible diaphragm336 is moved away from the closed position, fluid flows out of the valve and pressure decays down towards a non-zero value until the force exerted by thebiasing mechanism344 overcomes the force exerted on the flexible diaphragm by the medication within thepressure chamber322 such that the diaphragm closes over thepassageways314A,314B. The rate of fluid flow and therefore pressure decrease is controlled by therestrictors360A,360B. This control is important since too low of a restriction would not force a complete opening of the valve. In that case the restriction of flow across the valve seats would be significant and minor variations in manufacturing tolerances and/or finishes would control the flow resistance and resultant distribution. With proper flow restrictor selection, theapparatus310 fully opens and this does not occur.
• Likewise, when the[0193]flexible diaphragm36 is moved away from the closed position, Poutlet (inconduits328A,328B) quickly ramps up to a pressure substantially equal to or slightly less than Pinlet. While theflexible diaphragm336 is open, Pinlet tracks Poutlet. Since the resistance seen within the first andsecond passageways314A,314B is a result of the resistance of the first andsecond orifices360A,360B, Poutlet at the first andsecond outlet passageways314A,314B are substantially equal. Once theflexible diaphragm336 closes, Poutlet quickly drops back down to substantially zero.
• The pulsing method discussed above may be used in applications in which the[0194]medication delivery system10 delivers medicine to more than one site. The pulsing method may be used to control pressure and to facilitate the desired flow splitting characteristics. Additionally, the infusion tube set14 may include enhanced features to provide controlled restriction and anti-siphoning characteristics. As described above, in one embodiment the infusion tube set14 includes check valves and flow restrictors to provide the desired characteristics. In another embodiment, the infusion tub set includes the multiplesite infusion apparatus310.
• Returning to FIGS. 4 and 5, in one embodiment, the[0195]motor control circuit242 includes the motor sensor254 (see FIG. 4). Themotor sensor254 is coupled to themotor42 and is adapted to detect a revolution of themotor42 and to responsively generate a motor revolution signal in response to completion of themotor42 revolution. In one embodiment, themotor sensor254 is a opto-coupler sensor which is adapted to detect the presence of an indicating flag260 (see FIG. 5) connected to themotor42. The indicatingflag260 extends from one of the first and secondoutside cams64,66 to assist in monitoring the amount of the medication that has been delivered to thepatient12. Thesensor254 is optically-coupled with the indicatingflag260 to count revolutions of the indicatingflag260. Onesuitable sensor254 is available from Omron of Schaumburg, Ill., as model no. EE-SX1109.
• In one embodiment, the[0196]electronic controller118 is adapted to reset thewatchdog circuit248 prior to sending control signals to themotor42 control circuit to energize themotor42. Thewatchdog circuit248 is adapted to place thesecond switch252 in the opened state if two motor revolution signals are received without thewatchdog circuit248 being reset.
• In other words, the[0197]electronic controller118 must reset thewatchdog circuit248 prior to or between each revolution of themotor42. Thus, if a failure of theelectronic controller118 or themicroprocessor244 erroneously causes a control signal to be delivered to themotor control circuit242 to continuously place thefirst switch246 in the closed state, and thus, to erroneously energize themotor42, thesecond switch252 will be placed in the opened state. With thesecond switch252 in the opened state, power will not be delivered to themotor42.
• Additionally, if a failure of the[0198]first switch246 leaves thefirst switch246 in the closed state, successive motor revolution signals will be received by thewatchdog circuit248 without thewatchdog circuit248 being reset and thewatchdog circuit248 will place thesecond switch252 in the opened state, thus preventing power from being supplied to themotor42.
• In one embodiment, the[0199]electronic controller118 is adapted to track the time after a motor control signal has been sent and to enter a disabled state if the time between the sent control signal and received motor revolution signal exceeds a predetermined threshold.
• With specific reference to FIG. 26, in one embodiment the[0200]monitor circuit248 includes first and second flip-flops262,264. The first flip-flop262 is coupled to theelectronic controller118 and the second flip-flop264. The second flip-flop264 is coupled to thesecond FET258.
• In the illustrated embodiment, the first and second flip-[0201]flops262,264 are JK flip-flops. The inverse output (Q) of the second flip-flop264 is connected to the gate of thesecond FET258. The clock input (CLK) of the second flip-flop264 is coupled to the output (Q) of the first flip-flop262. Power is supplied by themicroprocessor244 to the first and second flip-flops262,264 to the J and K inputs of thefirst flop262 and to the J input of the second flip-flop264. The drain of thesecond FET258 is coupled to thefirst FET256 and the source of thesecond FET258 is connected to electrical ground.
• The[0202]watchdog circuit248 is reset by shutting off and restoring power to the first and second flip-flops262,264, to the J and K inputs of thefirst flop262, and to the J input of the second flip-flop264. In one embodiment, theelectronic controller118 shuts off power to the first and second flip-flops262,264 after each revolution of themotor42 and supplies power prior to turning on thefirst switch246 to begin the next cycle. This has two effects: conserving power and resetting the first and second flip-flops262,264.
• The clock input (CLK) of the first flip-[0203]flop262 is connected to the output of themotor sensor254. The clock input (CLK) of the first flip-flop262 is also connected to themicroprocessor244 via athird FET266. Thethird FET266 provides isolation between themicroprocessor244 and themotor sensor254 and themonitor circuit248. This isolation prevents a shorted pin on theelectronic controller118 from preventing revolution pulses from reaching the flip-flops262,264.
• The inverse clear input ({overscore (CLR)}) of the first and second flip-[0204]flops262,264 are coupled to themicroprocessor244 via abuffer circuit268. In the illustrated embodiment, thebuffer circuit268 includes afirst buffer270, afirst resistor272 and acapacitor274. Theelectronic controller118 may continuous supply power to themotor42 by turning on thefirst switch246 and continuously resetting the first and second flip-flops262,264 through the inverse clear inputs without turning off power to the flip-flops262,264.
• In one embodiment, the flip-[0205]flops262,264 are triggered by logic level high (“HIGH”) to logic level low (“LOW”) transitions. Thebuffer circuit268 prevents erroneous signal transitions when the input to thebuffer circuit268 is held HIGH by themicroprocessor244.
• With specific reference to FIG. 27, the[0206]motor control circuit242 includes thefirst FET256 and the opto-coupler sensor276. Aflashback diode278 is coupled across first andsecond motor junctions280A,280B. The opto-coupler sensor276 is coupled to thesecond motor junction280B. The transmitting diode of theopto coupler sensor276 is coupled to power (V+) and ground throughswitch256. In this arrangement thesensor276 is only powered during the time themotor42 is running thus conserving battery life. An output of the opto-coupler sensor276 is coupled to thethird transistor266 via asecond buffer282.
• The gate of the[0207]first FET256 is coupled to themicroprocessor244. The drain of thefirst FET256 is coupled to themotor42 and the source of thefirst FET256 is connected to the drain of thesecond FET258.
• As described above, the[0208]electronic controller118 is adapted to supply medication by energizing themotor42. A desired flow rate is achieved by energizing themotor42 and waiting between revolutions of themotor42 for a calculated period of time. Themotor42 is energized by turning on thefirst FET256. In the illustrated embodiment, thefirst FET256 is turned on by themicroprocessor244 by changing the state of the gate of thefirst FET256 from LOW to HIGH. If thesecond FET258 is also on, then power flows through themotor42 and the first andsecond FETs256,258. When themotor42 has made one (1) complete revolution, then the output of themotor sensor254 transitions from HIGH to LOW. In the illustrated embodiment, this transition is the motor revolution signal. The motor revolution signal is also transmitted to themicroprocessor244 via thethird FET266. After receiving the motor revolution signal themicroprocessor244 turns off thefirst FET256 by changing the state of the gate of thefirst FET256 from HIGH to LOW.
• During normal operation, the[0209]microprocessor244 then turns off power to the first and second flip-flops262,264. As described above, based on the desired flow rate and the known quantity of medication delivered per revolution of themotor42, themicroprocessor244 calculates a wait period between motor revolutions. After the wait period (or right before the wait period ends), themicroprocessor244 restores power to the first and second flip-flops262,264. As discussed above, this resets the first and second flip-flops262,264. Then themicroprocessor244 may again turn on thefirst FET256 to energize themotor42.
• If a failure condition of the[0210]control system240 exists, such as amicroprocessor244 failure or other failure, and thewatchdog circuit248 is not reset, thenwatchdog circuit248 turns off thesecond FET258, thereby preventing power from being supplied to themotor42.
• For example, if the[0211]microprocessor244 fails while thefirst FET256 is on, then themotor42 will continue to be energized. Themotor sensor254 will generate motor revolution signals each time a motor revolution is completed. However, themicroprocessor244 does not or is unable to reset thewatchdog circuit248. Two successive motor revolution signals received on the CLK input of the first flip-flop262 without thewatchdog circuit248 being reset will flip the inverse output of the second flip-flop264 (from HIGH to LOW) and thus turn off thesecond FET258.
• Likewise, a failure of the[0212]first transistor256 in the closed state will continuously energize themotor42. If themicroprocessor244 does not reset thewatchdog circuit248, then successive motor revolution signals received on the CLK input of the first flip-flop262 will flip the inverse output of the second flip-flop264 and thus turn off thesecond FET258.
• With the[0213]second FET258 in the off state, power will not be delivered to themotor42.
• Returning to FIG. 25, the[0214]control system240 further includes a key284 which is connected to theelectronic controller118 only during initialization. In one embodiment, the key284 is part of thetesting instrument200 which is also used to test thecontrol system240 after it has been assembled and thebatteries45 are installed. Upon initial power-up, thecontrol system240 will only initialize if the key284 is present. If the key284 is not present, then thecontrol system240 enters a disabled mode and medication cannot be delivered.
• In one embodiment, upon initial power-up the[0215]control system240 sends a signal to the key284. If present, the key284 delivers a return signal to thecontrol system240 indicating its presence. The use of the key284 ensures that thesystem10 cannot be improperly reset by removing and then re-inserting thebatteries45 orother power supply43. If this occurs and the key284 is not present, thesystem10 will not work.
• The[0216]control system240 includes acrystal285 coupled to themicroprocessor244. Thecrystal285 controls the frequency at which themicroprocessor244 operates in a conventional manner. However, if thecrystal285 is operating improperly, themicroprocessor244 could begin to operate at either a higher frequency or a lower frequency than intended. Themicroprocessor244 also includes aninternal oscillator286. In one embodiment, thecontrol system240 is adapted to compare a frequency of thecrystal285 with a frequency associated with theinternal oscillator286. Theelectronic controller118 adapted to compare a difference between the first and second frequencies and enter a disabled state if the difference is greater than a predetermined threshold. Thus, if thecrystal285 experiences a failure, thecontrol system10 will be disabled.
• The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.[0217]
• Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.[0218]

Claims (19)

What is claimed is:

1. A medication delivery system, comprising:

a reservoir for storing a supply of medication;

a pump assembly being coupled to the reservoir and having a pump inlet and a pump outlet, the pump assembly being controllable to provide a flow of medication in the form of a series of pulses, the pump outlet being subdivided into a plurality of legs; and,

a controller coupled to the pump assembly for controlling the pump assembly, the controller receiving a desired flow of medication and responsively controlling the pump assembly to provide a series of pulses of medication to provide the desired flow of medication, wherein the series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce an effect of any differential pressure between the legs.

2. A medication delivery system, as set forth inclaim 1, wherein the controller determines a period of time between a start of each pulse, wherein the period of time is determined such that each pulse begins before a predetermined drop in fluid pressure level occurs.

3. A medication delivery system, as set forth inclaim 1, wherein the series of pulses includes first and second groups of pulses, a start of each pulse within each group being separated by a first period of time and a start of the first pulse in each group being separated by a second period of time.

4. A medication delivery system, as set forth inclaim 3, wherein each group has a predetermined number of pulses.

5. A medication delivery system, as set forth inclaim 4, wherein the controller determines the second period as a function of the desired fluid flow.

6. A medication delivery system, as set forth inclaim 1, wherein the pump assembly includes:

a motor;

a cam shaft coupled to the motor; and,

first and second pinch levers in engagement with the cam shaft.

7. A medication delivery system, as set forth inclaim 6, wherein each of the first and second pinch levers comprise a cam follower, said cam followers being engaged by said cam shaft for alternating movement of said first and second pinch levers between said open and closed positions such that the medication can be delivered to the patient.

8. A medication delivery system, as set forth inclaim 7, wherein the pump assembly further includes a piston, the motor moving the piston to draw the medication into the pump assembly when the first pinch lever is in the open position and the second pinch lever is in the closed position, and to displace the medication from the pump assembly when the first pinch lever is in the closed position and said second pinch lever is in the open position.

9. A medication delivery system, as set forth inclaim 1, further comprising a multiple site infusion apparatus coupled between the pump outlet and the legs.

10. A medication delivery system, as set forth inclaim 9, wherein the multiple site infusion apparatus includes:

a valve housing having a first end and a second end, the first end including first and second outlet orifices; and,

a flexible diaphragm coupled between the cap and the valve housing and being movable from a closed position to and open position, the flexible diaphragm sealing the pressure chamber from the first and second outlet passageways when in the closed position and opening the first and second passageways to the pressure chamber when in the open position, the second end of the valve housing and the flexible diaphragm forming a pressure chamber, the valve housing further including an inlet passageway coupled to the pressure chamber and at least one outlet passageway coupled to the pressure chamber.

11. A medication delivery system, as set forth inclaim 10, further including a cap having a closed end and an open end and being coupled to the valve housing at the open end.

12. A medication delivery system, as set forth inclaim 10, wherein the outlet passageways of the multiple site infusion apparatus contain restrictive orifices.

13. A medication delivery system, as set forth inclaim 1, further comprising a valve system coupled to the pump outlet for providing flow restriction and anti-siphoning characteristics.

14. A medication delivery system, as set forth inclaim 13, the valve system including a divider for dividing the flow of medication into each leg and a check valve in each leg.

15. A mediciation delivery system, as set forth inclaim 13, wherein the valve system includes a divider for dividing the flow of medication into each leg and a flow restrictor in each leg.

16. A method for delivering medication using a medication delivery system, including the steps of:

storing a supply of medication;

receiving a desired flow rate of medication; and,

providing a flow of medication from the supply of medication in the form of a series of pulses, the flow being provided through an outlet and subdivided into a plurality of legs, wherein the series of pulses are determined to provide an outlet pressure at the pump outlet adapted to reduce an effect of any differential pressure between the legs.

17. A method, as set forth inclaim 13, including the step of determining a period of time between a start of each pulse, wherein the period of time is determined such that each pulse begins before a predetermined drop in fluid pressure level occurs.

18. A method, as set forth inclaim 14, wherein the series of pulses is subdivided into groups of pulses, a start of each pulse within each group being separated by a first period of time and a start of the first pulse in each group being separated by a second period of time.

19. A method, as set forth inclaim 14, wherein the second period of time is determined as a function of the desired fluid flow.

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