SENSOR CONTROLLED FLOW PATH FOR PROVJDtNG FLUIDS TO PATIENTS

RELATED APPLICATIONS

[0001] This application ciaims priority to U.S. Provisional Application Serial No. 61/197,040 filed October 24, 2008, entitled Sensor Controlled Flow Path of IV Pump Fluid, which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to systems and methods for providing fluids to patients, and more particularly to sensor controlled fluid flow paths and methods of use thereof.

BACKGROUND OF THE INVENTION

[0003] Infusion pumps are commoniy used to provide liquid medications and/or nutrients to patients. While infusion pumps are typically used for intravenous (IV) therapy, therapies in which liquid substances are infused directly into a vein, infusion pumps may also be used for subcutaneous, arterial and epidural infusions. There are numerous situations in which medical treatments benefit from or may be optimize by Sinking the administration of a medication into a patient to a patient sensor output.

[0004] For example, high and low blood glucose levels can place certain patients at risk. Blood glucose levels are reduced to an acceptable level by administering insulin via IV therapy. Close control of blood glucose requires that the insulin flow rate be increased or decreased to regulate the amount of insulin infused into the patient. In a hospital setting, a nurse must frequently monitor blood glucose levels and adjust the infusion pump rate up or down accordingly. This manual approach, in one extreme, is very time consuming, and in another extreme, places the patient at risk if the glucose level is not closely monitored and the flow rate properly adjusted. An obvious automated or semi-automated approach to handling this situation is to control insulin

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delivery to the patient by automatically adjusting the fluid output of the infusion pump by changing the pumping speed in response to a signal from a contra! unit that receives input from a glucose sensor. The concept of varying the infusion pump speed is, however, impractical for several reasons. First, the matter of replacing the population of infusion pumps in service with pumps that change output in response to information from a monitoring instrument would be prohibitively expensive. Second, the logistics of having a limited number of specialty pumps available where needed would be complicated as pumps are typically moved freely throughout a hospital.

[0005] Hence, there is a need for a fluid delivery system that can change the rate at which IV therapy fluid is delivered to a patient by an infusion pump that runs at a constant pump speed when a change in fiow rate is indicated by a sensor of an instrument that analyzes flow requirements.

OBJECTS AND SUMMARY OF THE INVENTION

[0006] The present invention provides a fluid delivery system that can change the rate at which SV therapy fluid is delivered to a patient by an infusion pump that runs at a constant pump speed when a change in flow rate is indicated by a sensor of a control instalment that analyzes flow requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other aspects, features and advantages of which embodiments of the invention are capable of wiii be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which:

[0008] Fig. 1 shows system components and a fluid flow path of certain embodiments of the present invention when it is intended that a fluid be provided to a patient.

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[0009] Fig. 2 shows system components and a fluid flow path of certain embodiments of the present invention when it is intended that a fluid flow to a patient be stopped.

J001Q] Fig. 3 shows system components and a fluid flow path of certain embodiments of the present invention when it is intended that fluid flow through a patient Sine be stopped and only a reduced fluid fiow be maintained to the patient.

DESCRIPTION OF EMBODIMENTS

[0011] Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure wili be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

[0012] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly forma! sense unless expressly so defined herein.

[0013] The present invention provides solutions for controlling the amount of fluid delivered to a patient by an infusion pump that runs at a fixed rate. As a general overview, the fluid passing through the pump is either delivered to the patient or is directed back to the inlet of the infusion pump. The flow path of the fluid is determined by the flow state of two valves. One valve controls fluid flow through a patient line and the other valve controls fluid flow through a bypass line, if one valve is open, the other

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is ciosecl. The valves' How states are controlled by a signa! sent from a control instrument that, in conjunction with a sensor, monitors a patient parameter, such as biood glucose. The present invention makes it possible to vary the amount of fluid delivered to a patient by an infusion pump set at a constant pumping rate by varying the valves' open and closed states in response to a signal from the control instrument.

[0014] fn some applications, it is necessary to maintain a continuous, Sow level of fluid flow through the patient line to prevent the needle or catheter from clotting closed. Accordingly, in certain embodiments of the present invention, a keep the vein open ("KVO") flow requirement is achieved by employing a KVO bypass line that bypasses the valve in the patient line. A flow resistor is employed within the KVO bypass line that allows a limited quantity of fluid to pass through the patient Sine regardless of the state of the patient line valve.

[0015] With reference to Fig. 1 , the components and configuration of a fluid flow system 1 are shown for one embodiment of the present invention. A fluid bag 10 is connected to a pump input line 12 that goes to an inlet of an infusion pump 14. An outlet of the infusion pump 14 is connected to a patient line 20. Within the patient line 20 a valve 18, e.g. a pinch valve, is employed to regulate flow of fluid to the patient. The interface of the patient line 20 and a patient access point, such as an intravenous or other fluid flow path access, is not shown. The fluid system 1 further comprises a bypass line 22 having one end connected to the pump input line 12 and a second end connected to the patient line 20 between the infusion pump 14 and the valve 18. Within the bypass line 22 a valve 24, e.g. a pinch valve, is employed to regulate flow of fluid through the bypass line 22. The arrows in Fig. 1 show the fluid flow path when the fluid from the fluid bag 10 is intended to flow to the patient access point. When fluid is intended to flow to the patient, the patient line 20 valve 18 is in an open state, and the bypass line 22 valve 24 is in a closed state.

[0016] The arrows in Fig. 2 show the fluid flow path of the fluid flow system 1 when it is intended that fluid flow to the patient should stop. When fluid flow to the patient is intended to stop, the fluid flow through the patient line 20 is diverted to a bypass line 22 by closing the valve 18 and opening the bypass valve 24. The bypass line 22 returns

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fluid flow back to the pump input line 12 where the diverted fluid again enters the infusion pump 14. When the valve 18 is in a dosed position, the pump input !ine 12; the infusion pump 14; and the bypass line 22 create a loop through which fluid is diverted from the patient line 20, without changing the flow setting of the infusion pump 14.

[0017] As previously mentioned, in certain situations, it may be necessary to maintain a Sow level of fluid fiow through the patient iine 20 to prevent the needle, catheter, or other patient access point (not shown) from clotting ciosed. i.e. a KVO fluid flow. Fig. 3 shows the components and configuration of a fluid fiow system 5 for one embodiment of the present invention. The arrows in Fig. 3 show the fluid fiow paths for system 5 when it is intended that fluid flow to the patient through patient line 20 be stopped and oniy a KVO fluid fiow be maintained to the patient. In fluid fiow system 5, a, KVO line 26 bypasses the valve 18 employed in the patient Sine 20. The KVO iine 26 has a flow resistor 28 that reduces fluid flow to a iower, KVO fluid fiow rate. Accordingly, when it is intended that fluid fiow to the patient should be stopped, a portion of the fluid is circulated through the infusion pump 14 via bypass ϋne 22, while a different portion of the fiuid continues to fiow to the patient at a KVO fluid flow rate through KVO iine 26.

[0018] It is noted that the pinch valve 18 and the bypass pinch vaive 24 are maintained in opposite states at substantially ail times. Stated aiternatively, when the fluid from the fluid bag 10 is intended to go to the patient the valve 18 is in an open state and the bypass vaive 24 is in a closed state. On the other hand, when it is intended that fluid fiow to the patient should be stopped, the valve 18 is in a closed state and the bypass valve 24 is in an open state.

[0019] In certain embodiments of the present invention, the open or ciosed states of the valve 18 and the bypass vaive 24 are controlied by a signal provided by wires 30 that are connected at one end to vaives 18 and 24 and at another end to a control instrument (not shown) that, in conjunction with a sensor (not shown), monitors one or more patient parameters. It will be understood by one of ordinary skill in the art that the wires 30 may be replaced by wireless forms of communication to achieve the same objectives. It will also be understood that sensor eiectronics may be incorporated into a

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patient monitor that is in turn in communication with the valve 18 and the bypass vaive 24 directly or via a control instrument.

[0020] Certain embodiments of the present invention are utilized, for example, to control fluid flow to the brain through a ventricular catheter. In operation, when a first sensor detects that the requisite amount of fluid has been delivered to the brain, fluid flow through the ventricular catheter is stopped by closing the patient line valve and opening the bypass line valve. When a second sensor indicates that the injected fluid volume has been returned to the fluid source reservoir, the control unit determines that it is safe and/or desirable to allow another injection of fluid though the ventricular catheter. As the first and second sensors, the system may, for example employ infrared sensors operable to sense fluid levels and to convey a corresponding signal to the control unit. The control unit may, in turn, employ software that directs the flow state of the patient line and bypass valves. The control unit may additionally provide data output to the user regarding the flow status of the system.

[0021] Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art. in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.

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