SYSTEMS AND METHODS FOR SUBSTANTIALLY CONTINUOUS INTRAVENOUS INFUSION OF THE SAME OR SUBSTANTIALLY THE SAME MEDICAL FLUID WITH FLUID SOURCE REPLACEMENTS

Disclosed in some embodiments is an electronic intravenous infusion pump provided with a disposable, insertable pump cartridge that is connectable to one or more intravenous fluid infusion sources, wherein the pump is coupled to a first fluid reservoir and a second fluid reservoir, wherein fluid is selectively drawn from the first fluid reservoir and the second fluid reservoir to provide substantially continuous infusion of substantially the same medical fluid to a patient.

BACKGROUND

Field

This disclosure relates to intravenous infusion pumps, including electronically controlled intravenous infusion pumps.

Related Art

Patients all over the world who are in need of medical care commonly receive intravenous infusion therapy, especially during surgery or when hospitalized. This process generally involves accessing the patient's veinous system via a needle or catheter, often placed in the hand or arm, and then coupling the needle or catheter to a tubing set in communication with one or more different types of therapeutic fluids. Once connected, the fluid travels from the fluid source(s), through the tubing set and catheter, and into the patient. The fluid can provide certain desired benefits to the patient, such as maintaining hydration or nourishment, diminishing infection, reducing pain, lowering the risk of blood clots, maintaining blood pressure, providing chemotherapy, and/or delivering any other suitable drug or other therapeutic liquid to the patient. Electronic infusion pumps in communication with the fluid sources and the patient can help to increase the accuracy and consistency of fluid delivery to patients, but current electronic infusion pumps present opportunities for further improvement.

SUMMARY

In some implementations, an electronic intravenous infusion pump is provided with a disposable, insertable pump cartridge that has at least two fluid inlets that are selectively connectable to two or more intravenous fluid infusion sources and/or supply lines, respectively. The pump can be configured to sequentially draw liquid beginning with an initial one of the fluid inlets until the intravenous fluid infusion source in communication with that fluid inlet is depleted, then transfer automatically to a different fluid inlet until the respective intravenous fluid infusion source in communication with that different inlet is depleted, and then again transfer automatically to yet another inlet or back to the initial inlet, and so on. The cycle is repeatable continuously by automatically transferring to draw liquid from a fluid source or supply line that is not empty, that is full, that contains liquid, or that has been replenished. In some implementations, a healthcare provider does not need to be present at the precise moment when a particular intravenous fluid infusion source becomes depleted to switch the fluid flow to another source or to replace or fill the depleted intravenous fluid infusion at that moment. Rather, the healthcare provider can set up a substantially continuous flow of intravenous fluid by programming the pump and then periodically replacing depleted intravenous fluid infusion sources or supply lines at a convenient time in his or her workflow. If air is introduced into a fluid line by a depleted fluid infusion source (e.g., an IV bag), the pump can be configured to sense the air and reverse the liquid flow to return the air into the depleted bag or into a new supply container without producing a clinically significant interruption in patient infusion. Air can also or alternatively be removed by trapping it in a disposable cassette.

In some implementations a control system for controlling operation of an infusion pump of an infusion pump system is provided. The infusion pump system can include a first fluid reservoir and a first supply line, a second fluid reservoir and a second supply line, a disposable cassette with an interior common channel in selective fluidic communication with the first fluid reservoir and the second fluid reservoir, and an infusion pump. The common channel can be in fluid communication with an outlet tube that is in fluid communication with a patient's venous system. The infusion pump is operable to drive fluid through the common channel into a patient delivery line. The system includes one or more hardware processors. The system includes a memory storing executable instructions that when executed by the one or more hardware processors, configure the infusion pump to: draw fluid from the first fluid reservoir through the common channel; automatically discontinue drawing fluid from the first fluid reservoir and begin drawing fluid from the second fluid reservoir through the common channel upon receiving an indication that the first fluid reservoir is depleted; and automatically discontinue drawing fluid from the second fluid reservoir and begin drawing fluid from the replaced or replenished first fluid reservoir through the common channel upon receiving an indication that the second fluid reservoir is depleted. Fluid drawn from the first fluid reservoir and delivered to the patient through the common channel can be substantially successively continuous with fluid drawn from the second fluid reservoir and delivered to the patient through the common channel. Further, incremental, sequential replacement or replenishment of the reservoirs could continue for many cycles, as necessary.

In some implementations, a method for controlling operation of an infusion pump of an infusion pump system is provided. The infusion pump system includes a first fluid reservoir, a second fluid reservoir, a common channel in selective fluidic communication with the first fluid reservoir and the second fluid reservoir, and an infusion pump. The infusion pump is operable to drive fluid through the common channel. The method includes drawing fluid from the first fluid reservoir through the common channel; automatically discontinuing drawing fluid from the first fluid reservoir and drawing fluid from the second fluid reservoir through the common channel upon receiving an indication the first fluid reservoir is depleted; and automatically discontinuing drawing fluid from the second fluid reservoir and drawing fluid from the replaced or replenished first fluid reservoir through the common channel upon receiving an indication that the second fluid reservoir is depleted. Fluid drawn from the first fluid reservoir through the common channel is substantially successively continuous with fluid drawn from the second fluid reservoir through the common channel. Further, incremental, sequential replacement or replenishment of the reservoirs could continue for many cycles, as necessary.

In some implementations a control system for controlling operation of an infusion pump of an infusion pump system is provided. The infusion pump system includes a first fluid reservoir, a second fluid reservoir, a common channel in selective fluidic communication with the first fluid reservoir and the second fluid reservoir (such as through the action of one or more valves), and an infusion pump. The infusion pump is operable to drive fluid through the common channel. The control system includes one or more hardware processors and a memory storing executable instructions that when executed by the one or more hardware processors, configure the infusion pump to: draw fluid from the first fluid reservoir through the common channel; automatically discontinue drawing fluid from the first fluid reservoir and draw fluid from the second fluid reservoir through the common channel upon receiving an indication that the first fluid reservoir is depleted; and automatically discontinue drawing fluid from the second fluid reservoir and draw fluid from the replaced or replenished first fluid reservoir through the common channel upon receiving instructions to draw fluid from the first fluid reservoir. Fluid drawn from the first fluid reservoir through the common channel is substantially successively continuous with fluid drawn from the second fluid reservoir through the common channel. Fluid delivered to the patient is substantially successively continuous across these transitions as well. Further, incremental, sequential replacement or replenishment of the reservoirs could continue for many cycles, as necessary.

In some implementations, a method for controlling operation of an infusion pump of an infusion pump system is provided. The infusion pump system includes a first fluid reservoir, a second fluid reservoir, a common channel in selective fluidic communication with the first fluid reservoir and the second fluid reservoir, and an infusion pump. The infusion pump is operable to drive fluid through the common channel. The method includes drawing fluid from the first fluid reservoir through the common channel; automatically discontinuing drawing fluid from the first fluid reservoir and drawing fluid from the second fluid reservoir through the common channel upon receiving an indication that fluid is depleted from the first fluid reservoir; and automatically discontinuing drawing fluid from the second fluid reservoir and drawing fluid from the replaced or replenished first fluid reservoir through the common channel upon receiving instructions to draw fluid from the first fluid reservoir. Fluid drawn from the first fluid reservoir and delivered to the patient through the common channel can be substantially successively continuous with fluid drawn from the second fluid reservoir and delivered to the patient through the common channel. Further, incremental, sequential replacement or replenishment of the reservoirs could continue for many cycles, as necessary.

DETAILED DESCRIPTION

This specification provides textual descriptions and illustrations of many devices, components, assemblies, and subassemblies for providing substantially continuous or “infinite” fluid infusion to a patient. Any structure, material, function, method, or step that is described and/or illustrated in one example can be used by itself or with or instead of any structure, material, function, method, or step that is described and/or illustrated in another example or used in this field. The text and drawings merely provide examples and should not be interpreted as limiting or exclusive. No feature disclosed in this application is considered critical or indispensable. The relative sizes and proportions of the components illustrated in the drawings form part of the supporting disclosure of this specification, but should not be considered to limit any claim unless recited in such claim. Fluid is a substance, such as a liquid or gas, that is capable of flowing and that changes its shape when acted upon by a moderate force. Liquid is a fluid that can be infused into a patient during intravenous therapy.

Examples of Advantages In Some Implementations

Patients frequently receive intravenous therapy from liquid source containers in the form of IV bags or syringes that are attached to electronically controlled large volume infusion pumps which draw from the source container. As liquid is pumped out of an IV bag, the walls of the bag draw together, effectively decreasing the volume within the bag; and as liquid is pumped out of a syringe by the action of the pump, the syringe plunger advances distally, effectively decreasing the liquid containing volume within the constant volume syringe barrel. In some embodiments, when a vented syringe adaptor is used to draw from a syringe, air can replace fluid expelled from the syringe volume. In some embodiments, an electronically readable data source can be provided on the first or second fluid source container or reservoir, such as an RFID tag, a barcode, or a QR code, that can provide any or all information relevant to a patient infusion, such as one or more of a patient's identification, the name of the medication in the source container or reservoir, the concentration of the medication in the source container or reservoir, and/or the administration instructions for the medication in the source container or reservoir.

In the busy workflow of hospitals and other healthcare settings, it is not always possible for healthcare providers to be present at the moment when a patient's IV bag is depleted in order to supply a new bag and reprogram the patient's IV pump for a new course of infusion. Thus, in many instances, a patient's IV infusion is temporarily halted while a patient waits for a healthcare provider to provide a new IV bag or syringe. However, for some patients, especially those under intensive medical care, a substantially continuous flow of certain medications is needed for an extended time period. For example, a patient may require continuous delivery of a vasoactive medication to maintain blood pressure, etc. When these medical fluids or any other suitable type of substantially continuously infused medical fluid are interrupted, the level of medication in the patient's blood stream may decrease below an acceptable level, the therapeutic effect may be diminished, and the patient's progress or healing may be halted or reversed. With respect to delivery from bags, clinicians can add fluid to an existing bag as the bag is in fluid communication with the pump and patient, which introduces confusion on the total volume remaining and the expiry of the bag, now with medication added at different times. Sometimes, clinicians also can hang another bag and fluidically connect it in parallel to the first bag upstream of the pump, which introduces the same limitations of unknown remaining available volume and expected expiry of now parallel infusions, and uses upstream ports on tubing sets to enable the introduction of incremental bags.

In some implementations, a substantially continuous flow of medical fluid can be provided to a patient even during transitions between infusion sources (e.g., when switching between depleted and fluid-containing IV bags or syringes), even when air is temporarily introduced into a pumping cassette or line, and/or even without requiring that a healthcare provider be present at the instant when a fluid source is depleted of fluid. An intravenous fluid infusion pump can be programmed to substantially continuously infuse medical fluid to a patient for an open-ended or effectively “infinite” time period, including when transitioning from a first fluid source to one or more other sources of substantially the same fluid and then back to the replaced or replenished first fluid source of substantially the same fluid in a substantially continuous manner. When a cassette-based infusion pump is used to draw fluid from source containers, the fluid sources can be in fluid communication with the cassette via a plurality of distinct ports on the upstream side of the cassette. A medical fluid cassette can be a disposable component that is configured to be quickly attached and removed from a medical fluid pump. The medical fluid cassette can receive fluid in an interior space and can include components that are useful in pumping, such as a pumping interface region, one or more medical fluid connectors, one or more air vents, and/or one or more sensors or sensing regions.

In some examples, depleted fluid or a deplete fluid container (such as an IV bag) can refer to a state of fluid or a fluid container that is in a depletion zone. A depletion zone is a state in which the fluid in the first fluid reservoir, the second fluid reservoir, or a subsequent fluid reservoir, is fully depleted or nearing depletion. For example, the depletion zone can include a state in which there is no fluid remaining in a reservoir (“fully depleted”), or there is only an amount of fluid remaining in a fluid reservoir that corresponds to up to about an inner volume of a fluid line extending between and connecting the fluid reservoir with another medical device (e.g., another medical fluid line, connector, cassette, cartridge, reservoir, or container), such that the remaining fluid in the reservoir can be transferred out of the reservoir and into the other medical device without introducing air or vacuum from the reservoir (“nearing depletion”). In some examples, the depletion zone can be represented as a state in which a reservoir contains an amount of fluid remaining in a fluid reservoir that will be fully depleted, leaving the reservoir completely empty, in a specified amount of time. For example, the depletion zone can be represented as a state in which an amount of fluid remaining in a reservoir will be fully depleted at a given rate of infusion within about thirty seconds or within about one minute. In some examples, the time period can be preset in the controller or set by a user. The depletion zone can be determined in any other way as described in any place in the specification. For example, the identification of a reservoir in a fluid depletion zone can be accomplished by electronically sensing the absence of fluid or the presence of an air bubble or vacuum in one or more portions of the system, such as one or more of a medical fluid reservoir, a medical fluid line, a medical fluid cassette, and/or a medical fluid connector (e.g., a Y-connector). The electronic sensing can be accomplished using any suitable device or method, such as infrared or ultrasonic sensing.

Depletion of a fluid source can be detected or sensed in one or more ways, including: (a) sensing of a fluid pressure reduction in a fluid line or within the cassette; (b) sensing air in a fluid line or within the cassette; and/or (c) sensing an “occlusion” in a syringe fluid source or creation of vacuum during the pump stroke caused by the syringe plunger reaching the distal end of the syringe barrel (which can be confirmed by verifying within the controller that the syringe volume, infusion rate, and infusion time are within range of depletion). Sensing of pressure and/or pressure change can be accomplished in one or more ways, including by using one or more piezoelectric sensors, strain-gauge sensors, acoustic sensors, light (e.g., infrared) sensors, etc. In some embodiments, the sensing of an occlusion can be detected or confirmed by determining a change (e.g., decrease or increase) in the force or electrical current required to move the pumping actuator (e.g., plunger).

When air is detected in the cassette or in a fluid line, it can be rapidly backprimed towards or into a depleted source container or towards or into a current fluid container from which liquid is being currently drawn (such as when the depleted source container has been removed for refilling). In some embodiments, backpriming is accomplished by modifying the opening and closing of the electronically-controlled valves (e.g., closing the outlet valve and opening one inlet valve during the pumping stroke and then, if necessary, opening one other inlet valve during the intake stroke) until the air is removed or purged from the cassette and/or fluid line. Infusion can immediately continue thereafter without significant interruption to the flow of therapeutic fluid to the patient. One or more depleted medical fluid containers can be temporarily detached, removed, and replaced, and/or refilled conveniently at any time during a healthcare provider's workflow while substantially the same medical fluid is being simultaneously infused into the patient from another fluid source container that is also attached to the infusion pump.

In some implementations, the electronic recording and tracking of total fluid infusion into a patient can be precise and comprehensive. Rather than maintaining a separate, discrete record or log of each bag or syringe of IV fluid infused into the patient, requiring a healthcare provider to add up all of the separate bag volumes of the same type of medical fluid to determine a total infused amount, the pump can be configured to record and/or display a continuously increasing amount of a single medical fluid or combination of medical fluids that has been infused into a particular patient over a particular time period.

In some implementations, the overall cost and waste relating to infusing medical fluid into a patient can be diminished. Some medical fluids are very expensive and are provided in large containers and small containers. In some situations, the volume of the large container is several times the volume of the small container. For a particular patient, it may not be necessary to infuse all of the medication provided in a large container; rather, the patient may need only a quantity of medication that could be provided through multiple administrations of small containers that together would be less than one large container. However, in some situations, busy healthcare providers recognize that they may not always be immediately available to replace a small container of medication when depleted with another small container of medication, which could cause an undesirable discontinuity in the patient's fluid administration. Therefore, they often simply attach a large container to the infusion pump but program it to infuse only a partial amount of the fluid and then discard the remaining fluid, thereby increasing the cost and waste of fluid administration. By permitting a healthcare provider to pre-attach multiple small volumes to the infusion pump and then configure the pump to automatically transition from one to the other, the healthcare provider does not need to be present at the precise moment during the transition and can administer only the amount needed by the patient, thereby saving money, decreasing waste, enabling automatic source transitions while the clinician is not in the patient's room, and avoiding discontinuities in the medical fluid supply to a patient.

Syringe pumps that controllably force fluid out of a syringe as opposed to drawing from the syringe as an aspect of a pump filling cycle, often have long start-up times to reach programmed target rates. This is due to the pump's absorption of mechanical slack as well as to pressurize the compliant syringe and consumable tubing set before achieving accurate delivery. This start up delay is particularly pronounced when the traditional syringe pump is programmed at low and very rates, for example less than a few mL/hr or less than 1 mL/hr. In some embodiments, a pump that draws from successive syringes diminishes the delay in delivery that would otherwise be introduced each time the syringe is changed on a traditional syringe pump.

Examples of Pump Systems

In some implementations, a pump system can include a reusable pump driver and a disposable temporary fluid holder, such as a fluid cassette, syringe, section of tubing, etc. A disposable cassette, which is typically adapted to be used only once for a single patient and/or only for limited time, is usually a small unit with a plastic housing having at least one inlet and an outlet respectively connected through flexible tubing to the fluid supply container and intravenously through a needle to the patient receiving the fluid. In some implementations, the cassette can include a pumping chamber. The flow of fluid through the chamber can be controlled by electronically actuated valves and a plunger or pumping element activated in a controlled manner by the pump driver. For example, the cassette chamber can have one wall formed by a flexible diaphragm or membrane against which the plunger is repeatedly pressed in a reciprocating manner, which causes the fluid to flow. The pump driver can include the plunger or pumping element for controlling the flow of fluid into and out of the pumping chamber in the cassette, and it may also include one or more controls and/or electronically actuated valves to help deliver the fluid to the patient at a pre-set rate, in a pre-determined manner, for a particular pre-selected time, and/or at a pre-selected total dosage.

In some implementations, during an intake pumping stroke, a first electronically controlled inlet valve can be opened and a second electronically controlled outlet valve can be closed. At the beginning of this stroke, the pump plunger and diaphragm or membrane begin in an inwardly displaced position inside of the pumping chamber. The pump plunger then withdraws from the pumping chamber, allowing the diaphragm or membrane to quickly retract or pull back from its prior inwardly displaced position to a resting position outside of the interior of the pumping chamber, effectively increasing the volume of the pumping chamber. This action draws fluid from the fluid source through the open inlet and into the pumping chamber. During a pumping stroke, the first electronically controlled inlet valve can be closed and the second electronically controlled outlet valve can be opened. The pump plunger then moves in the opposite direction, forcing the diaphragm or membrane back into the pumping chamber to advance the fluid contained in the pump chamber out through the outlet valve. By repeating this valving and pumping action in an electronically controlled manner, the fluid is urged into and out of the cassette in a series of pulses. When the pulses occur in rapid succession, the flow to the patient approximates a continuous flow.

In some embodiments, the intake stroke is very rapid (e.g., occurring over less than or equal to about 1 or about 5 seconds) but the pumping stroke is much slower (e.g., occurring over at least about 1 or about 2 or more minutes, or even extended over as long as about 2 or about 3 or more hours). The pumping stroke can be accomplished over many very small inwardly advancing steps by the pump plunger (e.g., at least about 100 steps or at least about 150 steps or at least about 500 or more steps). Although the fluid flow to the patient is interrupted intermittently for very short periods during the intake stroke, the overall fluid flow from the fluid source to the patient is substantially continuous. The interruptions in fluid flow can be of such short duration that they do not create clinically significant delays in fluid delivery to the patient. For example, the short interruptions do not normally lead to any clinically significant lowering of medication concentration in the patient's bloodstream because the time required to metabolize significant amounts of medication by a patient is much longer than the length of the individual interruptions.

Controlled pumping of fluid through a cassette can be accomplished in many ways. An example of methods and structures for pumping fluid through a cassette is disclosed in U.S. Pat. No. 7,258,534, which is incorporated by reference herein, for all that it contains, including but not limited to examples of pump drivers and disposable fluid holders. It is contemplated that any structure, material, function, method, or step that is described and/or illustrated in the '534 patent can be used with or instead of any structure, material, function, method, or step that is described and/or illustrated in the text or drawings of this specification.

Examples of Pump System Components

FIGS.1A-1Eshow an electronic medical intravenous pump10with a housing12and at least one electromechanical pump driver14attached to the housing12. As illustrated, a plurality of pump drivers14(e.g., at least two) can be integrally provided within the same housing12of a single medical pump10. Either or both of the pump drivers14can include a cover16that partially or entirely encloses an outer surface of the pump driver14, an indicator18(e.g., an illuminating communicator) attached to the cover16, one or more tube holders19, and a loader20configured to securely receive and releasably hold a disposable fluid holder (see, e.g.,FIGS.2A-2D), including but not limited to a cassette, syringe, and/or tubing. The one or more tube holders19can be configured to removably receive and securely hold one or more fluid-conveying tubes extending into or exiting from fluid holder when the fluid holder is received into the loader20. The indicator18can communicate one or more messages to a user, such as by temporarily illuminating in one or more colors. Examples of one or more messages include confirming that a pump driver14near the indicator is currently active and pumping or that one or more instructions being received from a user will apply to a pump driver14near the indicator18. The loader20can be a mechanism with multiple moving parts that opens, closes, expands, contracts, clasps, grasps, releases, and/or couples with the fluid holder to securely hold the fluid holder on or within the pump10during fluid pumping into the patient. The loader20can be integrated into and positioned on or within the pump10near the cover16adjacent to the indicator18.

A user communicator, such as display/input device200, can be provided to convey information to and/or receive information from a user (e.g., in an interactive manner). As illustrated, the user communicator is a touch screen that is configured to provide information to a user through an illuminated dynamic display and is configured to sense a user's touch to make selections and/or to allow the user to input instructions or data. For example, the display-input device200can permit the user to input and see confirmation of the infusion rate, the volume of fluid to be infused (VTBI), the type of drug being infused, the name of the patient, and/or any other useful information. The display-input device200can be configured to display one or more pumping parameters on a continuing basis, such as the name of the drug being infused, the infusion rate, the volume that has been infused and/or the volume remaining to be infused, and/or the elapsed time of infusion and/or the time remaining for the programmed course of infusion, etc. As shown, the touch screen can be very large, for example at least about 4 inches×at least about 6 inches, or at least about 6 inches×at least about 8 inches. In the illustrated example, the touch screen fills substantially the entire front surface of the pump10(seeFIG.1A), with only a small protective boundary surrounding the touch screen on the front surface. As shown, the touch screen comprises at least about 80% or at least about 90% of the surface area of the front of the pump10. In some implementations, the front of the touch screen comprises a clear glass or plastic plate that can be attached to the housing20in a manner that resists liquid ingress, such as using a water-proof gasket and/or adhesive that can withstand repeated exposure to cleaning and sanitizing agents commonly used in hospitals without significant degradation.

An actuator21can be provided separate from the user communicator. The actuator21can be configured to receive an input and/or display information to a user. As shown, the actuator21is a power button that permits the user to press on the actuator21to power up the pump10. The actuator21can illuminated to communicate to the user that the pump10is power on. If the power source is running low, the actuator21can change the color of illumination to quickly show to a user that a power source needs to be replenished.

In some implementations, the user communicator, such as a display/input device200, can alternatively or additionally comprise one or more screens, speakers, lights, haptic vibrators, electronic numerical and/or alphabetic read-outs, keyboards, physical or virtual buttons, capacitive touch sensors, microphones, and/or cameras, etc.

During use, the pump10is typically positioned near the patient who is receiving fluid infusion from the pump10, usually lying in a bed or sitting in a chair. In some implementations, the pump10may be configured to be an ambulatory pump, which will typically include a smaller housing, user communicator, battery, etc., so as to be conveniently transportable on or near a mobile patient. In many implementations, the pump10is attached to an IV pole stand (not shown) adjacent to the patient's bed or chair. As shown, the pump10can include a connector80that is configured to removably attach the pump10to the IV pole stand. As shown, the connector80can comprise an adjustable clamp with a large, easily graspable user actuator, such as a rotatable knob81, that can be configured to selectively advance or retract a threaded shaft82. At an end of the shaft82opposite from the knob81is a pole-contacting surface that can be rotatably advanced by the user to exert a force against a selected region of the pole, tightly pushing the pole against a rear surface of the pump10, thereby securely holding the pump10in place on the pole during use. The selected region of the pole where the contacting surface of the shaft82is coupled can be chosen so as to position the pump10at a desired height for convenient and effective pumping and interaction with the patient and user.

The pump10can include a power source90. In some implementations, the power source can comprise one or more channels for selectively supplying power to the pump10. For example, as illustrated, the power source90can comprise an electrical cable92configured to be attached to an electrical outlet and/or a portable, rechargeable battery94. One or more components of the pump10can operate using either or both sources of electrical power. The electrical cable92can be configured to supply electrical power to the pump10and/or supply electrical power to the battery94to recharge or to maintain electrical power in the battery94.

Inside of the housing20of the pump10, various electrical systems can be provided to control and regulate the pumping of medical fluid by the pump10into the patient and/or to communicate with the user and/or one or more other entities. For example, the pump can include a circuit board that includes a user interface controller (UIC) configured to control and interact with a user interface, such as a graphical user interface, that can be displayed on the user communicator or display/input device200. The pump10can include a printed circuit board that includes a pump motor controller (PMC) that controls one or more pump drivers14. In some implementations, the PMC is located on a separate circuit board from the UIC and/or the PMC is independent from and separately operable from the UIC, each of the PMC and UIC including different electronic processors capable of concurrent and independent operation. In some implementations, there are at least two PMC's provided, a separate and independent one for each pump driver14, capable of concurrent and independent operation from each other. The pump10can include a printed circuit board that includes a communications engine (CE) that controls electronic communications between the pump10and other entities (aside from the user), such as electronic, wired or wireless, communication with a separate or remote user, a server, a hospital electronic medical records system, a remote healthcare provider, a router, another pump, a mobile electronic device, a near field communication (NFC) device such as a radio-frequency identification (RFID) device, and/or a central computer controlling and/or monitoring multiple pumps10, etc. The CE can include or can be in electronic communication with an electronic transmitter, receiver, and/or transceiver capable of transmitting and/or receiving electronic information by wire or wirelessly (e.g., by Wi-Fi, Bluetooth, cellular signal, etc.). In some implementations, the CE is located on a separate circuit board from either or both of the UIC and/or the PMC(s), and/or the CE is independent from and separately operable from either or both of the UIC and/or the PMC(s), each of the PMC(s), UIC, and CE including different electronic processors capable of concurrent and independent operation. In some implementations, any, some, or all of the UIC, CE, and PMC(s) are capable of operational isolation from any, some, or all of the others such that it or they can turn off, stop working, encounter an error or enter a failure mode, and/or reset, without operationally affecting and/or without detrimentally affecting the operation of any, some, or all of the others. In such an operationally isolated configuration, any, some, or all of the UIC, CE, and PMC(s) can still be in periodic or continuous data transfer or communication with any, some, or all of the others. The UIC, PMC(s), and/or CE can be configured within the housing20of the pump10to be in electronic communication with each other, transmitting data and/or instructions between or among each of them as needed.

FIG.2Ashows an example of a disposable fluid holder, such as a disposable cassette50, that includes a plastic housing and a flexible, elastomeric silicon membrane. Any structure, material, function, method, or step that is described and/or illustrated in U.S. Pat. No. 4,842,584, which is incorporated herein by reference in its entirety, including but not limited to the pumping cassette, can be used by itself or with or instead of any structure, material, function, method, or step that is described and/or illustrated in this specification. The plastic housing of the cassette50can include one or more (e.g., two as shown) fluid inlets52and a fluid outlet54formed in a main body56. The cassette50can be temporarily positioned for example in the loader20of a pump driver14. The one or more fluid inlets52are coupled with one or more inlet tubes57in fluid communication with one or more sources of medical fluid, such as one or more IV bags, vials, and/or syringes, etc., containing medical fluid. If multiple inlets52and inlet tubes57are provided, as shown, then multiple sources of medical fluid can be simultaneously supplied to a patient through the cassette50. The fluid outlet54is coupled to an outlet tube55in fluid communication with the patient, normally by way of a needle leading into a patient's blood vessel.

A flexible, elastomeric membrane forms a diaphragm60within a pumping chamber66on an inner face68of the main body56. In operation, fluid enters through one or more of the inlets52and is forced through the outlet54under pressure. One or more fluid channels within the main body56of the cassette50convey the fluid between the inlets52and the outlet54by way of the pumping chamber66. Before use, the cassette is typically primed with fluid, usually saline solution. A volume of fluid is delivered to the outlet54when a plunger136of the pump10(see, e.g.,FIG.3) displaces the diaphragm to expel the fluid from the pumping chamber66. During an intake stroke, the plunger136retracts from the diaphragm60, and the fluid is then drawn in through the inlet52and into the pumping chamber66. In a pumping stroke, the pump10displaces the diaphragm60of the pumping chamber66to force the fluid contained therein through the outlet54. In some implementations, the directional movement of flow can be facilitated by one or more supply line selection valve(s) (e.g., at one or more of inlet52or outlet54). For example, the supply line selection valve(s) can initially be configured and controlled to direct fluid from a first fluid reservoir58a(e.g., bag or syringe) into the common channel61. At a later time, the supply line selection valves can be configured and controlled to switch to directing fluid from a second reservoir58binto the common channel61instead of from the first fluid reservoir58a. The fluid can flow from the cassette50in a series of spaced-apart pulses rather than in a continuous flow. In some implementations, the pump10can deliver fluid to a recipient (e.g., a patient) at a pre-set rate, in a pre-determined manner, and for a particular (e.g., pre-selected) time or total dosage. The cassette50can include an air trap59in communication with an air vent (not shown).

FIGS.2B,2C, and2Dshow three views of a cassette that is the same as or similar to the cassette ofFIG.2A. InFIGS.2B and2C, fluid can flow into an inlet52, from a primary container, for example. Fluid can also flow into a secondary port253, which can have a Y-connector with a resealable opening or a locking cap. Fluid coming in from the inlet52can pass through an A valve220. Fluid coming in through a secondary port253can pass through a B valve218. Fluid coming in through these two valves can then pass by a proximal air-in-line sensor222. Fluid can then pass by, in a widening passage, a proximal pressure sensor223.

FIG.2Eshows an example of a cassette that is the same as or similar to the cassette ofFIG.2Acoupled to syringes63a63b. The inlets52are each coupled to resealable needle-free medical connectors67known as the Microclave connectors sold by ICU Medical, Inc. in San Clemente, California. Each of the needle-free medical connectors67are disposed between and coupled to one of the syringes63a,63b.

Cassette Air Trap

The widened passage can form an air trap chamber59, which can allow for fluid mixing. The air trap chamber is also shown in the side view ofFIG.2B. The air trap chamber59can be integral to the cassette. The air trap can be exposed to view above the upper edge of the cassette door when the door is closed. Air passes the proximal air-in-line sensor222before entering the air trap, which in some implementations can have a volume of at least about 2.0 mL (e.g., 2.15 mL). The proximal pressure sensor (see, e.g., pressure sensor223ofFIG.3C) can monitor pressure in the air trap chamber59. In some implementations, the user can remove air or fluid from the proximal tubing and cassette air trap after the cassette door is closed. To remove air in the trap or the proximal tubing the user may be required to attach a container to a Line B port (e.g., secondary port253ofFIG.2C). A key, button, or other control (e.g., on an infuser display screen) can be selected to backprime when a delivery is not in progress. When the user selects backprime, for example, this can initiate rapid pumping of fluid from Line A to a user-attached container on Line B. In some implementations, no fluid is delivered to the cassette distal line during a backprime. After the backprime control is released, a cassette leak test can be automatically performed.

In some implementations, after passing through an air trap chamber59, fluid can subsequently flow through an inlet valve228and from there into a pumping chamber66. The pumping chamber66is also shown in the side view ofFIG.2D. From the pumping chamber66, fluid can flow through an outlet valve231and then into a widened passage accessed by a distal pressure sensor232. This passage subsequently narrows down to pass a distal air-in-line sensor236. The two air-in-line sensors, proximal222, and distal236, can both be positioned near a bend in a passage or tubing, as shown in the side views ofFIGS.2B and2D. Fluid can flow through or pass a precision gravity flow regulator267, seen inFIG.2D. A finger grip245is also seen protruding to the right inFIG.2D. An outlet tube55is also shown coming from the precision gravity flow regulator267and leading to a patient. The features shown in the cross-sectional schematics ofFIGS.2B-2Dcan correspond generally to the external cassette contours shown inFIG.2A.

Fluid Delivery

A pumping system or infuser can deliver fluids from two or more fluid sources through a sterile fluid pathway of administration set tubing, accessories, and a cassette. In some implementations, there is no contact between the fluid and an infusion mechanism subsystem (seeFIG.3Aand the electromechanical portion356ofFIG.3C). In some implementations, the pumping force can be provided by one or more of the structures, configurations, processes, and/or control systems shown inFIGS.2A through3D, but many other additions or alternatives can also be used, including a peristaltic or a syringe pump with suitable valving and valve controls of the type disclosed in one or more implementations in this specification to help accomplish substantially continuous infusion.

In some implementations, a pumping system can be programmed or set up by a user to enter a multi-step therapy program to perform an infusion of the same or substantially the same medical fluid in a substantially continuous manner by automatically sequentially delivering fluid from a first line and then from one or more additional lines and then returning to the first line. Fluid flow to the patient is still considered to be substantially continuous even though short interruptions in patient fluid flow may occur during the fluid intake stroke of pumping, or during automatic transitions between one line and another after fluid source depletion is detected, or during air or bubble purging steps. Substantially continuous fluid flow can include short, discrete, and/or predictable interruptions in fluid flow that do not lead to clinically significant decreases in infused fluid volume or medication concentration in a patient's bloodstream. For example, in some situations, the automatic switching of fluid source containers can occur in less than or equal to about 10 seconds, while the “half life” of medication concentration in the bloodstream is much longer, such as at least about 2 minutes, and in most cases much longer than that.

An additional or alternative infusion pump cassette that can be used with any implementation in this specification is illustrated in FIG. 5 of U.S. Pat. No. 7,402,154. An elastomeric membrane60forms an inlet diaphragm62, an outlet diaphragm generally indicated at64, and a pumping chamber66located between the inlet and outlet diaphragms62and64on an inner face68of the main body56. In operation, fluid enters through the inlet52and is forced through outlet54under pressure. The fluid is delivered to the outlet54when the plunger136of the pump10displaces the pumping chamber66to expel the fluid. During the intake stroke the plunger136releases the pumping chamber66, and the fluid is then drawn through the inlet52and into the pumping chamber66. In a pumping stroke, the pump10displaces the pumping chamber66to force the fluid contained therein through the outlet54. The directional movement of flow can be facilitated by one or more supply line selection valve(s) (e.g., at one or more of inlet52or outlet54). At low rates the flow can be delivered in discrete volumes as the pump10displaces the pump chamber in successive steps. Thus, the fluid can flow from the cassette50in a series of spaced-apart pulses rather than in a smoothly continuous flow. Typically, this pump can deliver fluid to a recipient (e.g., a patient) at a pre-set rate, in a pre-determined manner, and for a particular (e.g., pre-selected) time or total dosage. A flow stop can be formed as a switch in a main body and protrude from the inner surface68. This protrusion can form an irregular portion of the inner surface68which can be used to align the cassette50as well as monitor the orientation of the cassette50. The flow stop can provide a manual switch for closing and opening the cassette50to fluid flow. A rim72is located around the outer surface of the main body56and adjacent the inner surface68. The rim72can be used to secure the cassette in a fixed position relative to the pump10of U.S. Pat. No. 7,402,154.

FIG.3Aillustrates an example of hardware or components of the pump driver14that can be configured to interact with a fluid holder such as the cassette ofFIGS.2A-2D. InFIG.3A, an A valve interface320can correspond to or interact with an A valve220. Similarly, a B valve interface318can correspond to or interact with a B valve218as shown inFIG.2C. A proximal air-in-line sensor322can be located outside of a cartridge and can interact with a loop or bend in at least partially transparent fluid pathway, for example. In the illustrated example, the sensor322is depicted with two vertical portions that can pinch or otherwise be positioned adjacent to a tube running vertically between them. A proximal pressure sensor interface323can interact with a pressure sensor223. A force-sensor, such as resistor325, can be used to determine whether a cartridge is in physical contact with the hardware, or a portion of a pump having the hardware, shown inFIG.3A. In some implementations, an inlet valve228is actively driven and can receive actuation from an inlet valve interface328. Similarly, an outlet valve interface331can interact with an outlet valve231. A plunger343can extend toward and interact with a pumping chamber66(seeFIGS.2C and2D). A cassette locator335can be used to provide alignment and registration of physical interacting components when a cassette such as shown inFIGS.2A-2Dis inserted into or aligned with the hardware components shown inFIG.3A. A distal pressure sensor interface332is located below a distal air-in-line sensor336. Above this is located a regulator actuator367, which can be configured to interact with the precision gravity flow regulator267.

FIG.3Billustrates a fluid path from the first fluid reservoir58aand the second fluid reservoir58bthrough a common channel61of a cassette such as the fluid path shown in the cassette(s) ofFIGS.2A-2D, as actuated by the hardware ofFIG.3A. The physical components ofFIGS.2A-2DandFIG.3Acan control and evaluate fluid in the path illustrated inFIG.3B. InFIG.3B, fluid coming in from either a primary line57A or a secondary line57B can pass through the A valve220or the B valve218, respectively. The medical fluid can pass by a proximal in line air sensor322in the common channel61to permit a processor in the pump to detect whether there are air bubbles or vacuum space in the fluid and/or whether a fluid source has been depleted. In some situations where the A valve220and the B valve218are rapidly opening and closing, the incoming fluid can merge and/or mix in the common channel61. However, when the cassette is used for substantially continuous fluid infusion of the same or substantially the same medical fluid, the fluid coming in from both the primary line57A and the secondary line57B is the same or substantially the same. In a first phase, the pump is configured so that the A valve220is opened and the B valve218is closed until the air sensor322and processor detect that fluid coming from the primary line57A is depleted, at which point in a second phase the A valve is closed and the B valve218is opened until the air sensor322and processor detect that the fluid coming from the secondary line57B is depleted, at which point the pump returns to the first phase in which A valve220is opened again and the B valve218is closed again. While the B valve218is open and fluid is pumping from the secondary line57B, the healthcare provider can replace the depleted fluid source attached to the primary line57A with a new container of substantially the same fluid (e.g., a new IV bag) and/or can refill the depleted fluid source attached to the primary line57A with substantially the same fluid. Similarly, while the A valve220is open and fluid is pumping from the primary line57A, the healthcare provide can replace the depleted fluid source attached to the second line57B with a new container of substantially the same fluid (e.g., a new IV bag) and/or can refill the depleted fluid source attached to the secondary line57B with substantially the same fluid. This pattern or cycle of automatic pump and valve control, and fluid source replacement by the healthcare provider, can continue indefinitely until stopped by the healthcare provider or until an error occurs (e.g., when a depleted bag is not replaced before the pump begins drawing from that bag).

After passing through the common channel61within the cassette, the medical fluid can then enter an air trap chamber59having a proximal pressure sensor223. From here, fluid can flow through an inlet valve228and from there into a pumping chamber66. From the pumping chamber66, fluid can flow through an outlet valve231, past a distal pressure sensor232, and past a distal air-in-line sensor336. Fluid can flow through or pass a precision gravity flow regulator267before proceeding from a cassette toward a patient through tubing.

In a system using active, positively-controlled valves with motors, during fluid delivery, the plunger (e.g.,343inFIGS.3A and3C) can repeatedly cycle between the home position and the extended position. To draw fluid into the pumping chamber (e.g.,66) the inlet valve (e.g.,228) is opened. The outlet valve can then promptly close. In some implementations, opening of the inlet valve can automatically cause the outlet valve (e.g.,231) to close. When the plunger reaches the home position, the plunger motion pauses while the inlet valve (e.g.,228) is closed, pressure is equalized, and the outlet valve (e.g.,231) is opened. Then the plunger extends and the positive pressure forces fluid out of the pumping chamber and into the distal line (e.g.,55) of the set, which can be connected to a patient.

The plunger stepper motor (e.g., motor342ofFIG.3Cor the motor ofFIG.4C) can be activated by current pulses through the motor windings. In some implementations, a plunger motor can use different patterns (e.g.,6different patterns) of pulses can be used, depending on the delivery rate. As the rate increases, a pause between successive steps of the motor decreases. In some implementations, valve motors can use a single pattern of current pulses through the motor windings. The patterns of current pulses for the motors are advantageously controlled by a PMC microcontroller (e.g., in the controller380).

FIG.3Cfurther illustrates schematically how hardware (e.g.,FIG.3A) can interact with a cassette (e.g.,FIGS.2A-2D) along a fluid path.FIG.3Cshows a patient or distal line55at the top left corner. At the left is shown an example of a consumable or cassette portion352. At the right is shown an example of an electromechanical portion356. In the cassette352, a distal side353is toward the left, and a proximal side354is toward the right. A fluid path351is illustrated, passing generally from inlets57A and57B to outlet55. Line A57A leads to a Line A valve or pin220, which can move to the right and left as shown by the arrow. Similarly, Line B57B can lead to a Line B valve or pin218. A spring such as the spring381can be deployed with respect to both the valve218and the valve220, and a cam371can connect a stepper motor370with the valve to220and the valve218. The stepper motor370can interact with a line AB position sensor372, with feedback373provided to a controller or controllers380. A controller380can in turn provide input and/or power374to the stepper motor370. In this arrangement, the valves220and218are actively and positively controlled by a motor and a controller.

For the outlet valve and pin231and the inlet valve and pin228, a stepper motor377having a cam378and associated springs382can interact with the valves228and231. In some implementations, the cam371can cause the associated valves220,218not to be opened simultaneously. In some implementations, the inlet valves220and218are not open simultaneously so that fluid does not mix in either of inlet lines57A or57B.

Similarly for the cam378and the valves231and228, if the cam forms a rigid elongate structure as shown, it can pull on one valve while pushing on the other and when it swings the other direction push and pull in an alternating manner. The valves228and231can open at alternating times such that fluid intake occurs during a draw portion of a plunger stroke, and fluid is expelled during a push portion of a plunger stroke. Having the valves open simultaneously or other synchronization problems can be avoided to discourage backflow.

An input-output valve position sensor379can be connected to a physical component of the stepper motor377. The sensor379can provide feedback to the controller or controllers380, which can in turn send input and/or power376to the stepper motor377.

The controller or controllers380can also interact with a third stepper motor342, which can cause movement of a lead screw341connected to a plunger or piston343, which in turn physically interacts with the pumping chamber66. A linear position sensor345can provide feedback346of this process to a controller380. Similarly, a rotary position sensor347can provide feedback384to a controller380. Thus, linear and rotary position feedback can be provided either as a backup, as an alternative, or otherwise. A coupler344can be provided between the stepper motor of342and the lead screw341. Input and/or power385can be provided from the controller380to the stepper motor342. The plunger or piston343can follow a reciprocating pattern as shown by the arrow. Thus, the electromechanical portion356of a pump can have multiple reciprocating portions and multiple motors. The reciprocation of the valves220,218,231and228can be timed and coordinated with the reciprocation of the piston343(e.g., by controller/s380) to encourage fluid to move through the fluid path351. Although additional feedback lines are not shown inFIG.3C, sensor feedback can be provided from the distal air inline sensor236and the proximal area line sensor222, as well as the distal pressure sensor232and the proximal pressure sensor223.

Valve Operation

Valve motors such as the motors370and377ofFIG.3Ccan be controlled by a pump mechanism controller (“PMC”) microcontroller using a chopper motor drive. The valve motors370and377can be the same, with one motor used for a pair of valves.

An Inlet/Outlet (I/O) valve motor (e.g.,377inFIG.3C) opens and closes the cassette pumping chamber inlet and outlet valves (e.g.,228,231) in an administration set cassette. The cassette can have a membrane that is exposed by openings in the back of the cassette body above where there are valve chambers in the cassette. The inlet valve pin (e.g.,228) is opened to allow fluid to enter the pumping chamber (e.g.,66) through the air trap (e.g.,59) from the proximal line, which is selected by the Line A/B Select valves (e.g.,218,220). When the pumping chamber is filled the inlet valve (e.g.,228) is closed, the pumping chamber pressure is set and the outlet valve (e.g.,231) is opened to allow fluid to be pumped into the distal line of the set.

A state machine (e.g., in or associated with the controller380) can run a program for controlling the I/O valve motor (e.g.,370,377). In an optical approach, cam flags can protrude from a portion of the drive train. Rotational cam flag signals can be acquired optically during or after each motor step and are monitored using a state machine. As with the other motors, if there is an error in the Inlet/Outlet valve motor position (phase loss), then the motor can be re-initialized to the current position.

The Line A/B Select (LS) valve motor (e.g.,370inFIG.3C) opens and closes the Line A and Line B select valves (e.g.,220,218) in the administration set cassette, using openings in the back of the cassette body for actuator access. The Line A valve (e.g.,220) controls the primary inlet port to the cassette which can be attached permanently to the set proximal tubing. The Line B valve (e.g.,218) controls the secondary inlet port, which may have a screw cap, a Pre-pierced or a Clave attached to it, depending on the type of set.

Example System Operations

In some implementations, a pump system can have a cassette door with a handle that supports an administration set cassette such as that illustrated inFIGS.2A-2D. When the door is open in a loading position the user can slide the cassette into a slot with a cassette guide spring. When the door is closed the cassette is aligned and the front of the cassette makes contact with a door datum surface, actuator and sensor subassemblies (plunger343and pins or valves218,220,228,231) make contact with a cassette elastomeric membrane, and a cassette guide spring can push a fluid shield against the front face of a mechanism chassis. The door can be released from the handle when it is in the loading position, allowing the door to be perpendicular to the mechanism fluid shield. This allows the user to clean the rear of the door and the fluid shield, or to remove any object which has fallen behind the door.

A cassette locator (see, e.g.,335inFIG.3A) can be a pin that helps align the cassette with the mechanism as the door is closed and keeps the cassette in the correct position during delivery.

The cassette can have a flow regulator valve (e.g., the precision gravity flow regulator267, seen inFIG.2D) distal to the pumping chamber (e.g., the chamber66ofFIGS.2A-3D). The flow regulator valve can be closed by the user after an administration set is primed. The proximal line can be clamped as an additional prevention of free flow. As the door is closed, an actuator connected to the door handle can automatically open the flow regulator valve after the pumping chamber outlet valve pin closes the outlet valve. The flow regulator valve can be used by the operator to control fluid flow rate when the administration set is used independently for a gravity drip infusion.

A reciprocating pumping piston/plunger (e.g., the plunger343ofFIG.3C) can be actuated by a motor (e.g., the motor342). As schematically shown inFIG.3C, a pump plunger motor and drive train can be perpendicular to a pumping chamber membrane opening on the rear of a cassette. The drive train can have location sensors that are monitored by motor control software on a PMC microcontroller (see controller380ofFIG.3C). The software can implement state machines which control the motor operation.

An inlet valve to the pumping chamber (e.g., the valve228) can be actuated by a motor (e.g., the motor377), and a drive train can extend an actuator through an opening in the rear of the cassette to reach the valve. The same motor can be used for the outlet valve, which can improve synchronization. A default position is with the inlet valve (e.g., the valve228) closed by a spring (e.g.,382) which can apply steady pressure to a valve pin. The drive train (see generally377,378and related structures) has a location sensor (e.g.,379) that is monitored by (383) motor control software on the PMC microcontroller (e.g.,380). The software implements state machines which can control the motor operation. The same description here generally applies to an outlet valve (e.g.,231), actuated by the same motor (e.g.,377).

Line A select valve (e.g.,220) for primary proximal fluid line A (e.g.,57A) and Line B select valve (e.g.,218) for fluid line B (e.g.,57B) can be actuated by a motor (e.g.,370). As described above for the valves228and231, the valves220and218can be accessed by a drive train (which may include the cam371and springs such as381) through openings in a cassette, driven by a motor (e.g.,370), as tracked by a location sensor (e.g.,372) and monitored (373) by software in a controller (380).

One or more proximal and distal air-in-line sensors (222,236) can be used to detect air passage into (proximal) or out of (distal) the cassette. Both sensors can be ultrasound piezoelectric crystal transmitter/receiver pairs. Liquid in the cassette between the transmitter and receiver conducts the ultrasonic signal, while air does not. This can result in a signal change indicating a bubble in the line.

One or more proximal and distal MEMS pressure sensors (223,232ofFIG.3C) can be used to detect the pressure of the tubing into (proximal) or out of (distal) the cassette. Microelectromechanical systems (MEMS) pressure sensors are an integrated circuit, which have piezo electric resistors diffused into a micro-machined diaphragm to measure strain from a steel ball that extends through the top of the IC package. The steel ball is driven by a pressure pin which is in contact with the cassette membrane.

A cassette presence sensor detects that the cassette is in the door when it is closed. The sensor can be a dome switch mounted in an infusion mechanism subsystem fluid shield. The dome switch can make contact with the cassette when the cassette is correctly aligned with the fluid shield. The switch output signal can be acquired and processed by PMC microcontroller software (e.g., in controller380).

Motor control interfaces can provide amplification of control signals output by the PMC microcontroller (e.g., the controller380). PMC microcontroller software can compute motor winding current values which are converted to analog voltages by a digital-to-analog converter (DAC). The control voltages input to the motor control interface can cause amplifiers to drive the selected motor winding with current modulated by a chopper pulse width modulator controller. Preferably, one motor winding is active at a time.

Sensor interfaces in an infusion mechanism subsystem can convert air-in-line, pressure, and/or motor drive position sensor signals into analog voltage signals. The analog voltages are processed by an analog-to-digital converter (ADC) in the PMC microcontroller which outputs digital values. PMC microcontroller software state machines acquire and process data from the sensors.

Non-volatile memory in an infusion mechanism subsystem can be connected to the PMC microcontroller with a serial communications link (SPI bus). The non-volatile memory can be used to store calibration values for the motor drive trains and sensors during manufacturing. Additional system parameters and an alarm log are also stored by the PMC microcontroller in this memory.

Any control and/or feedback systems of this specification can be configured to generate highly specific, real-time data on how an infusion pump is operating and how fluid in a cassette is responding. This data already exists for precision operation of an infusion device, and it can be conveniently organized and stored (e.g., in a memory of the pump system itself). This data can provide highly accurate predictions of how and when medication will reach a target destination or achieve a particular level in a target destination. Thus, the sensors, controllers, cam flags, feedback software, etc. described herein is highly valuable in predicting further outcomes, patient medication status, and/or otherwise displaying information to a user.

FIG.3Dis a schematic diagram of some functional components for a medical pump (e.g., the pump10ofFIGS.1A-1E) that in some implementations can be configured with some modifications to be used in connection with the disposable cassette50(e.g., a modified version ofFIGS.2A-D) for delivering a fluid to a patient. Some of the components and/or functions illustrated and/or described in connection withFIG.3Dare alternatives or additions to those illustrated in the cassette ofFIGS.2A-3C. One or more processors or processing units280can be included in pump10that can perform various operations. The processing unit(s)280and all other electrical components within the pump10can be powered by a power supply281, such as one or more components of power source90of pump10. In some implementations, the processing unit280acan be configured as a pump motor controller (PMC) to control the electric motor142being energized by the power supply281. When energized, the electric motor142can cause the plunger136to reciprocate back and forth to periodically actuate, press inward, and/or down-stroke, causing plunger136to temporarily press on pumping chamber66, driving fluid through cassette50. The motor142, plunger136, sensors128,290,132,140,266,144can be included in or as an integrated part of the pump driver14of the pump10. In some implementations, as shown, the inlet pressure sensor128engages the inlet diaphragm62of cassette50, and the outlet pressure sensor132engages the outlet diaphragm64of cassette50. When retracting, moving outward, or on an up-stroke, the plunger136can release pressure from pumping chamber66and thereby draw fluid from inlet52into pumping chamber66. Differential pressure within the cassette can drive the inlet opening during the pump chamber fill cycle. In some implementations of cassette50, a flow stop70is formed as a pivotal switch in the main body56and protrudes a given height from the inner surface68. This protrusion forms an irregular portion of the inner surface68which can be used in some implementations to align the cassette50as well as monitor the orientation of the cassette50. In some implementations, one form of a flow stop70can provide a manual switch or valve for closing and opening the cassette50to fluid flow.

In some implementations, the processing unit280acan control a loader20of the pump10with an electronic actuator198and a front carriage being energized by the power supply281. When energized, the actuator198can drive the front carriage74between closed or open positions. The front carriage74in the open position can be configured to receive the cassette50and in the closed position can be configured to temporarily securely retain the cassette50until the front carriage is moved to the closed position. A position sensor266for the cassette50can be provided in the pump10. The position sensor266can monitor the position of a slot268formed in a position plate270. The position sensor266can monitor a position of an edge272of a position plate270within the pump10. By monitoring the position of the position plate270, the position sensor266can detect the overall position of the front carriage of the loader20and/or confirm that the cassette50is inserted into the loader20of the pump driver14. The position sensor266can be a linear pixel array sensor that continuously tracks the position of the slot268. Of course, any other devices can be used for the position sensor266, such as an opto-tachometer sensor.

A memory284can communicate with the processing unit280aand can store program code286and data necessary or helpful for the processing unit280to receive, determine, calculate, and/or output the operating conditions of pump10. The processing unit280aretrieves the program code286from memory284and applies it to the data received from various sensors and devices of pump10. The memory284and/or program code286can be included within or integrally attached to (e.g., on the same circuit board) as the processing unit280a, which in some implementations can be the configuration for any processor or processing unit280in this specification.

In some implementations, the program code286can control the pump10and/or track a history of pump10operation details (which may be recorded and/or otherwise affected or modified, e.g., in part by input from sensors such as air sensor144, position sensor266, orientation sensor140, outlet pressure sensor132, plunger pressure sensor290, inlet pressure sensor128, etc.) and store and/or retrieve those details in the memory284. The program code286can use any one or more of these sensors to help identify or diagnose pumping problems, such as air in a pumping line, a pumping obstruction, an empty fluid source, and/or calculate expected infusate arrival time in a patient. The display/input device200can receive information from a user regarding a patient, one or more drugs to be infused, and details about a course of infusion into a patient. The display/input device200can provide a clinician with any useful information regarding the pumping therapy, such as pumping parameters (e.g., VTBI, remaining volume, infusion rate, time for infusion, elapsed time of infusion, expected infusate arrival time, and/or time for completion of infusion, etc.) Some or all of the information displayed by the display/input device200can be based on the operation details and calculations performed by the program code286.

In some implementations, the operation details can include information determined by the processing unit280a. The processing unit280acan process the data from pump10to determine some or all of the following operating conditions: whether or when the cassette50has been inserted, whether or when the cassette50is correctly oriented, whether or when the cassette50is not fully seated to the fixed seat162, whether or when the front carriage assembly74is in an open or closed position, whether or when a jam in the front carriage assembly74is detected, whether or when there is proper flow of fluid through the cassette50to the patient, and whether or when one or more air bubbles are included in the fluid entering, within, and/or leaving cassette50. The processing unit280acan be configured to determine one or more operating conditions to adjust the operation of the pump10to address or improve a detected condition. Once the operating condition has been determined, the processing unit280acan output the operating condition to display200, activate an indicator window, and/or use the determined operating condition to adjust operation of the pump10.

For example, the processing unit280acan receive data from a plunger pressure sensor290operatively associated with the plunger136. The plunger pressure sensor290can sense the force on plunger136and generate a pressure signal based on this force. The plunger pressure sensor290can communicate with the processing unit280a, sending the pressure signal to the processing unit280afor use in helping to determine operating conditions of pump10.

The processing unit280acan receive an array of one or more items of pressure data sensed from the cassette inner surface68determined by the plunger pressure sensor290and inlet and outlet pressure sensors128and132. The processing unit280acan combine the pressure data from the plunger pressure sensor290with data from inlet and outlet pressure sensors128and132to provide a determination as to the correct or incorrect positioning of cassette50. In normal operation, this array of pressure data falls within an expected range and the processing unit280acan determine that proper cassette loading has occurred. When the cassette50is incorrectly oriented (e.g., backwards or upside down) or when the cassette50is not fully seated to the fixed seat162, one or more parameters or data of the array of pressure data falls outside the expected range and the processing unit280adetermines that improper cassette loading has occurred.

As shown, in some implementations, the processing unit280acan receive data from one or more air sensors144in communication with outlet tube55attached to the cassette outlet54. An air sensor144can be an ultrasonic sensor configured to measure or detect air or an amount of air in or adjacent to the outlet54or outlet tube55. In normal operation, this air content data falls within an expected range, and the processing unit280acan determine that proper fluid flow is in progress. When the air content data falls outside the expected range, the processing unit280acan determine that improper air content is being delivered to the patient.

Processing unit280acan continuously or periodically communicate with an independent and separate processor or processing unit280bto communicate information to the user and/or to receive data from the user that may affect pumping conditions or parameters. For example, processing unit280acan communicate by wire or wirelessly with processing unit280bwhich can be configured as a user interface processor or controller (UIC) to control the output and input of display/input device200, including by displaying an operating condition and/or activate indicator18to communicate with a user. In some implementations, processing unit280bcan receive user input regarding pumping conditions or parameters, provide drug library and drug compatibility information, alert a user to a problem or a pumping condition, provide an alarm, provide a message to a user (e.g., instructing a user to check the line or attach more fluid), and/or receive and communication information that modifies or halts operation of the pump10.

An independent and separate processor or processing unit280ccan be configured as a communications engine (CE) for the pump, a pump communications driver, a pump communications module, and/or a pump communications processor. Processing unit280ccan continuously or periodically communicate with processing units280aand280bto transmit and/or receive information to and from electronic sources or destinations separate from, outside of, and/or remote from, the pump10. As shown, processing unit280ccan be in electronic communication with or include a memory284and program code286, and processing unit280ccan be in communication with and control data flow to and from a communicator283which can be configured to communicate, wired or wirelessly, with another electronic entity that it separate from the pump10, such as a separate or remote user, a server, a hospital electronic medical records system, a remote healthcare provider, a router, another pump, a mobile electronic device, a near field communication (NFC) device such as a radio-frequency identification (RFID) device, and/or a central computer controlling and/or monitoring multiple pumps10, etc. The communicator283can be or can comprise one or more of a wire, a bus, a receiver, a transmitter, a transceiver, a modem, a codec, an antenna, a buffer, a multiplexer, a network interface, a router, and/or a hub, etc. The communicator283can communicate with another electronic entity in any suitable manner, such as by wire, short-range wireless protocol (Wi-Fi, Bluetooth, ZigBee, etc.), fiber optic cable, cellular data, satellite transmission, and/or any other appropriate electronic medium.

As shown schematically inFIG.3, a pump10can be provided with many components to accomplish controlled pumping of medical fluid from one or more medical fluid sources to a patient. For example, one or more processors or processing units280can receive various data useful for the processing unit(s)280to calculate and output the operating conditions of pump10. The processing unit(s)280can retrieve the program code286from memory284and apply it to the data received from various sensors and devices of pump10, and generate output(s). The output(s) are used to communicate to the user by the processing unit280b, to activate and regulate the pump driver by the processing unit280a, and to communicate with other electronic devices using processing unit280c.

Substantially Continuous Infusion

In some implementations, the user can enter a therapy program that sequentially delivers fluid from a first line, then from one or more other lines, and then from the first line again. For example, the first line can be used to start delivering a first quantity of medical liquid. After fluid delivery from the first line is completed, then the second line delivery is automatically started. In some implementations, the processor280is configured to provide substantially continuous infusion during operation such that the pump10alternates between drawing fluid from the first fluid reservoir58aand the second fluid reservoir58b(and/or from other reservoirs) generally seamlessly and without significant interruption of fluid flow to the patient. The first fluid reservoir58aand the second fluid reservoir58bcan be replaced and/or refilled any desired number of times without interrupting infusion to a patient. The fluid in the first fluid reservoir58aand the fluid in the second fluid reservoir58bcan be the same or substantially the same (e.g., the same or substantially the same type of fluid and/or the same concentration of fluid), and the fluid that replaces the fluid in the first fluid reservoir58awhen depleted and the fluid in the second fluid reservoir58bthat replaces the fluid in the second reservoir58bwhen depleted can be the same or substantially the same, such that a patient can receive a uniform or substantially the same supply of medical fluid when the pump10draws fluid from the first fluid reservoir58aor the second fluid reservoir58b. Providing a generally uniform, same, or substantially the same, type of fluid from the first fluid reservoir58aand the second fluid reservoir58ballows a healthcare provider to replenish a medical fluid supply in the first reservoir58aor the second reservoir58bwithout interrupting infusion to a patent in a clinically significant way. Providing substantially continuous infusion also allows a healthcare provider to replace one of the fluid reservoirs58a,58bwithin an extensive window of time while the pump10draws from the alternate fluid reservoir58a,58b.

In some embodiments, when a healthcare provider desires to program the pump10for substantially continuous or “infinite” infusion between or among multiple, successive fluid sources, a user can begin by pressing a button or series of buttons on a touchscreen or in hardware on the pump10to initiate the substantially continuous infusion process. The pump10can prompt the user to attach at least two fluid sources with the same or substantially the same fluid contents to the cassette that is inserted into the pump10. If the healthcare provider attaches only one fluid source, the pump10can remind the healthcare provider to attach the second fluid source. If the healthcare provider initiates pumping before attaching the second fluid source, the pump10can begin pumping but also remind and allow the healthcare provider to attach the second fluid source at any time before the first fluid source is depleted, which still permits substantially continuous infusion. In some embodiments of substantially continuous fluid infusion, the healthcare provider has flexibility to set up the additional fluid source at any point over a long period of time during infusion of the existing fluid source without requiring the healthcare provider to be present at the exact instant when a fluid source is depleted.

FIG.4is a flow diagram showing an implementation of substantially continuous infusion using the pump10. In the implementation shown inFIG.4, the pump10provides a substantially successively continuous flow of medical fluid during a generally seamless and substantially uninterrupted transition between drawing from the first reservoir58ato drawing from the second reservoir58b, at which point fluid in the first fluid reservoir58ais replaced or refilled. Upon depletion of medical fluid in the second reservoir58b, the pump10then provides a generally seamless and substantially uninterrupted transition to drawing medical fluid from the first reservoir58bwhile fluid in the second fluid reservoir58bis replaced or refilled.

In the example shown inFIG.4, the internal computer program code286includes steps, instructions, algorithms, and/or data configured to cause the pump10to draw fluid402from the first fluid reservoir58athrough the common channel61of the cassette50. The processing unit280areceives an indication that the first fluid reservoir58ais depleted404(such as by detecting air or the absence of liquid at the air-in-line sensor322when the reservoir is a bag, or by monitoring upstream pressure via pressure sensor223when the reservoir is a syringe), and automatically discontinues406drawing fluid from the first fluid reservoir58a. The processing unit280aactuates supply line selection valves in the cassette, causing the pump to draw fluid from the second fluid reservoir58b. The processing unit280areceives an indication that the second fluid reservoir58bis depleted410(such as by detecting air or the absence of liquid at the air-in-line sensor322when the reservoir is a bag, or by monitoring upstream pressure via pressure sensor223when the reservoir is a syringe), automatically discontinues412drawing fluid from the second fluid reservoir58b, and draws414fluid from the first fluid reservoir58a. The fluid in the first and second fluid reservoirs58a,58bcan be substantially the same. In some implementations, the pump10continues to selectively and alternatively draw fluid from the first reservoir58aand the second reservoir58buntil the pump receives a signal from a user to stop drawing fluid or until the pump10encounters an error condition (such as when a depleted reservoir has not been replaced or refilled). In some implementations, the pump10continues to draw fluid for a preset period of time or until a preset amount of fluid has been drawn collectively from the first fluid reservoir58aand the second fluid reservoir58b. In some embodiments the preset period of time or preset amount of fluid drawn can be based on a known volume in the reservoir and understood pumping rates, where reservoir volume could be entered by a clinician or obtained by the pump electronically, such as via a bar code or RFID tag on the reservoir.

To draw402fluid from the first fluid reservoir58a, the processing unit280atransmits an electrical signal to the supply line selection valves of the cassette50, which selectively control the flow of fluid from the first fluid reservoir58aand the second fluid reservoir58binto the common channel61. As such the supply line selection valves cause the common channel61to be in selective fluidic communication with the first fluid reservoir58aand the second fluid reservoir58b. The supply line selection valves as controlled by the processing unit280adirect the fluid from the first fluid reservoir58athrough the cassette50to the outlet of the cassette. In some implementations, fluid enters the cassette from the first fluid reservoir58athrough one or more of the inlets52and is forced through the outlet54by the pumping mechanism. The common channel61within the main body56of the cassette50conveys the fluid between the inlets52and the outlet54by way of the pumping chamber66. The volume of fluid is delivered to the outlet54when a plunger136of the pump10(see, e.g.,FIG.3) displaces the diaphragm to expel the fluid from the pumping chamber66.

The processing unit280areceives indication from at least one sensor or from user input or from internal processing or calculation, that the first fluid reservoir58ais depleted404. The indication can be triggered by one or more of a plurality of events. For example, the processing unit280acan be configured to halt the flow of fluid after drawing fluid from a reservoir having a known volume at a known fluid flow rate for a predetermined period of time. In some implementations, the processing unit280areceives an indication from a timer that the pump10has been drawing fluid from the first fluid reservoir58afor a period of time sufficient to empty the first fluid reservoir58a. Alternatively or additionally, in some implementations, the processing unit280areceives a pressure reading from the pressure sensor223, which can selectively be in fluidic communication with the first fluid reservoir58aand the second fluid reservoir58b. The pressure sensor223monitors the fluid pressure from an outlet of the first fluid reservoir58aand an outlet of the second fluid reservoir58band transmits an electrical signal to the pump10indicating when fluid from the first fluid reservoir58ais no longer providing fluid pressure through the pressure sensor223. For example, the proximal pressure sensor223can provide a signal to the processing unit280awhen fluid from the first fluid reservoir58aprovides an upstream fluid pressure that is below a threshold pressure and indicating that air is present in the line and/or the fluid in the first fluid reservoir58ais depleted. In some implementations, pressure measurement is taken by a plurality of pressure sensors. For example, in some implementations, a separate pressure sensor is used to measure pressure from the first fluid reservoir58aand the second fluid reservoir58brespectively. In some implementations, the air-in-line sensor322detects that air or a lack of fluid is present in at least a portion of the common channel61, indicating that the reservoir from which the fluid is being drawn has been depleted.

Alternatively or additionally, the first fluid reservoir58amay be coupled to an electronic scale that is capable of determining a weight of the first fluid reservoir58aand sending a signal to the processing unit280awhen the weight of the fluid reservoir falls below a threshold weight, indicating that the first fluid reservoir58ais depleted. In some implementations, the threshold weight is an estimated weight of a container of the fluid reservoir that does not contain any liquid or contains a minimal amount of liquid. Alternatively or additionally, in some implementations, a user can manually indicate that the first fluid reservoir58ais depleted. For example, a user can interact with the GUI of the display/input device200to send a signal to the processing unit280aindicating that the first fluid reservoir58ais depleted.

To draw fluid from the second fluid reservoir58b, the processing unit280atransmits an electrical signal to the supply line selection valves, which selectively control the flow of fluid from the first fluid reservoir58aand the second fluid reservoir58binto the common channel61. As such, the supply line selection valves cause the common channel61to be in selective fluidic communication with the first fluid reservoir and the second fluid reservoir. The supply line selection valves as controlled by the processing unit280adirect the fluid from the second fluid reservoir58athrough the cassette50to the outlet54of the cassette In some implementations, fluid enters the cassette50from the second fluid reservoir58athrough one or more of the inlets52and is forced through the outlet54under pressure. The common channel61within the main body56of the cassette50conveys the fluid between the inlets52and the outlet54by way of the pumping chamber66. The volume of fluid is delivered to the outlet54when a plunger136of the pump10(see, e.g.,FIG.3) displaces the diaphragm to expel the fluid from the pumping chamber66.

The processing unit280acan be configured to receive indication from at least one sensor or from user input or from internal processing or calculation, that the second fluid reservoir58bis depleted404in one or more of the same ways as described for receiving indication that the first fluid reservoir58a is depleted. When the processing unit280areceives the indication that the second fluid reservoir58bis depleted, the processing unit280astops drawing fluid from the second fluid reservoir58band switches back to drawing fluid from the first fluid reservoir58aas before. In some implementations, the pump10is configured to only draw fluid from the respective first fluid reservoir58aand the second fluid reservoir58bwhen the pump10receives an indication of fluid availability such as fluid pressure, threshold weight, or manual indication by a user interaction with the user interface.

The reservoir in any of these embodiments can be any suitable container, such as a bag, syringe, vial, or other rigid, semi-rigid or flexible container. In embodiments where the reservoir is a bag, a length of tubing can be provided (such as57inFIG.2A, or57A/B inFIG.4) with upstream volume that complements the reservoir. The volume of the tubing can be significant and included in volume calculations for the reservoir. When the reservoir directly connects to the cassette, such as in the case of a syringe, the volume of fluid between the reservoir and the common line can be quite small and may not need to be included in volume calculations for the reservoir.

Reserve Bag Example

FIG.5is a flow diagram showing an implementation of substantially continuous fluid flow using the pump10. In the implementation shown inFIG.5, the pump provides a continuous flow of fluid drawn from the first fluid reservoir58aas a primary reservoir. The pump10draws fluid from the second fluid reservoir58bas a reserve reservoir while a user is replacing the first reservoir58a. The pump10resumes drawing from the first fluid reservoir58aonce the first fluid reservoir58ais replaced. For example, as shown inFIGS.5, the internal computer program code286can include steps, instructions, algorithms, and/or data configured to cause the pump10to draw fluid502from the first fluid reservoir58athrough the common channel61of the cassette50. The processing unit280areceives indication that the first fluid reservoir58ais depleted504, and automatically discontinues506drawing fluid from the first fluid reservoir58a. The internal computer program code286causes508the pump10to draw fluid from the second fluid reservoir58b. The processing unit280areceives instructions to draw510fluid from the first fluid reservoir58aagain upon an indication that the first reservoir is no longer depleted. Upon receiving instructions to draw510fluid from the first fluid reservoir58a, the pump10automatically discontinues512drawing fluid from the first fluid reservoir58aand draws514from the second fluid reservoir58b. In some implementations, a user such as a physician or medical technician can interact with the GUI to send instructions to the processing unit280a, to draw fluid from the first fluid reservoir58aonce the user has replaced the depleted first fluid reservoir58a. As such, the second fluid reservoir58bcan be used to provide infinite infusion during multiple replacements of the first bag and can be replaced while the first fluid reservoir58ais providing a primary fluid flow to a patient.

Replacing Reservoirs

FIG.6Ashows that, during typical fluid flow from an intravenous pump, the detection of a depletion of a fluid source, the summoning of a healthcare worker to locate a replacement for and replace the depleted fluid source, and/or the attachment of a new fluid source, can introduce a significant time gap in patient infusion. In many healthcare settings, the size of the time gap is inconsistent and indeterminate because the time gap can change based on how soon a healthcare worker has the ability to replace the fluid source that is depleted. During this time gap, the fluid volume or concentration of medicine in the bloodstream of the patient may decrease significantly through natural metabolization by the patient to a point where the therapeutic effect of the IV therapy may be significantly diminished or lost. Further, when the delivery occurs via a traditional syringe pump the replacement of a depleted syringe can introduce the time delay from exchanging syringes. Additionally another time delay may arise from the syringe pump re-establishing accurate flow at the desired rate from a “cold start”.

FIG.6Bis an example infusion rate versus time diagram that shows a constant infusion rate as the pump10selectively draws from the first fluid reservoir58aand then switches essentially immediately to the second fluid reservoir58b.FIG.6Cis an example infusion rate versus time diagram that shows a more typical yet still clinically-acceptable infusion profile that can provide a substantially constant rate that can include small increases and decreases in fluid flow that are not clinically significant for a particular medication and patient, including those that occur during: (a) transitions between intake and pumping strokes (while pumping from the same source container); (b) transitions between different source containers; and/or (c) elimination or purging of air or vacuum from the pumping lines or cassette. In some embodiments of a substantially continuous infusion system, one or more of these or other short interruptions can be monitored, managed, fixed, resolved, and/or mitigated automatically by the electronic controller of the pump without any user alert and/or without any user intervention. A substantially constant rate may include intermittent interruptions and/or increases or decreases in infusion rates that are not clinically significant in view of the range of typical metabolizing rates of medications in particular categories of patients (e.g., based on age, weight, sex, drug tolerance, type of disease, injury, or other malady). For example, in some embodiments a substantially continuous infusion rate can include interruptions in flow that are consistently and predictably less than a predetermined time period that does not significantly adversely affect medication concentration in a patient, such as less than or equal to about 20 seconds, less than or equal to about 1 minute, less than or equal to about 2 minutes, or less than or equal to about 3 minutes.

In the examples shown inFIGS.4-5, a user such as a physician can replace the first fluid reservoir58awith a reservoir containing fluid (e.g., a full fluid reservoir) or replenish the first fluid reservoir when the first fluid reservoir58ais determined to be empty or depleted. Fluid can be drawn by the pump from the second fluid reservoir58bwhile the fluid in the first fluid reservoir58a(or the first fluid reservoir58aitself) is being replaced. Similarly, a healthcare provider can replace the second fluid reservoir58bwith a reservoir containing fluid (e.g., a full fluid reservoir) or replenish the second fluid reservoir when the second fluid reservoir58bis determined to be empty or depleted and fluid is being drawn from the first fluid reservoir58a. Each of the first fluid reservoir58aand the second fluid reservoir58bcan be fluidically disconnected from line A and Line B respectively. A replacement first fluid reservoir58aand second fluid reservoir58bcan be fluidically connected to Line A and Line B respectively, putting each of the first fluid reservoir58aand the second fluid reservoir58bin selective fluidic communication with the common channel61. The fluid flow can be substantially continuous when the processing unit280aactivates the supply line selection valve to direct fluid from each of the respective fluid reservoirs58a,58b.

Backpriming During Substantially Continuous Infusion

In some implementations, the pump10is configured to backprime to remove any air or any excess air that may enter Line A, Line B, or the common61line upon depletion of a particular reservoir or during the transition between drawing fluid from the first fluid reservoir58aand the second fluid reservoir58b. For example, the pump10can backprime during at least one instance where air or a region lacking fluid from a reservoir is drawn into the cassette and detected by a sensor upon depletion of the reservoir or while the pump10alternates between drawing from the first fluid reservoir58aand the second fluid reservoir58b. The pump10can backprime to remove air from the trap or the proximal tubing and move it into an empty first fluid reservoir58aor second fluid reservoir58b. In some implementations, a key, button, or other control (e.g., on an infuser display screen) can be selected to backprime when a delivery is not in progress. When the user selects backprime, for example, this can initiate rapid pumping of fluid from Line A and the common channel to the second fluid reservoir58bin Line B in an example where the second fluid reservoir58bis depleted and the pump10is drawing from the first fluid reservoir58a. Similarly, backpriming of the depleted first fluid reservoir can be accomplished by rapid pumping of fluid from Line B and the common channel to the first fluid reservoir58ain Line A.

Backpriming can occur when the pump controller or processor is configured to actuate the valving and pumping motor to temporarily and for a short period reverse the flow of fluid so that an air bubble or region lacking medical fluid detected in the cassette can be eliminated by returning it to the recently depleted fluid source. Fluid is not drawn in from the patient line during backpriming. In some implementations, for a series of pumping cycles sufficient to eliminate the air bubble or region lacking medical fluid, the outlet valve231is closed, the inlet valve228is opened and the respective one of the inlet valves218,220that is in fluid communication with the recently depleted fluid source is opened during the pumping strokes and the opposite of inlet valves218and220is opened during the intake strokes. After a sufficient number of strokes, the air bubble or region lacking medical fluid in the cassette can be returned to the recently depleted fluid source. In some embodiments, (for example,FIG.2B), backpriming can move fluid towards the depleted Line B line57band/or reservoir58b, with valve231and218closed and valves228and220opened during the pump intake cycle and valve231and220closed and valves228and218opened during the pump expel cycle. In some embodiments, backpriming can move fluid towards the depleted Line A reservoir58a, with valve231and220closed and valves228and218opened during the pump intake cycle and valves231and218closed and valves228and220opened during the pump expel cycle.

Backpriming can be managed by the clinician who manually initiates the backpriming, visually observes air removal from the cassette area up to the Line B container, and then stops the action. In some embodiments, backpriming towards depleted Line A of reservoir58acan be used. Either backpriming to Line B or to Line A can be clinician-managed or initiated, and/or managed automatically by the pump, to prime lines back to a reservoir spike such as58aor58b. Further, either backpriming to line A or line B can be clinician-managed or initiated and managed automatically by the pump to prime lines back to ports such as253(FIG.2C). Backpriming can be done upon system recognition of the accumulated air sensing or pressure sensing, or after each reservoir depletion. Cassette-based pump infusion dedicated consumable sets can include an integrated tubing line terminating with a proximal bag spike (e.g., as the primary Line A), and a direct access port on the cassette (e.g., Line B), which can accommodate a direct connection of a syringe or of secondary tubing connected to a secondary bag. Alternatively, cassette-based infusion pumps can couple with cassettes that include two access ports, which can accommodate direct access for connected syringes or line access to bags. In the case where a line to a reservoir is present, it may be preferable to remove system air by back-priming fluid all the way to the reservoir. Similarly, when a port is available as cassette access, it may be preferable to remove air by back-priming just to the port.

In some implementations, the backpriming is initiated automatically. For example, in some implementations, the control system sends an electrical signal to the pump10to automatically backprime when the system alternates between drawing from the first fluid reservoir58aand the second fluid reservoir58b, even without detecting an air bubble or region lacking medical fluid in the cassette. In some implementations, the control system sends an electrical signal to the pump10to backprime when the first fluid reservoir58ais depleted, or when the second fluid reservoir58bis depleted, even without detecting an air bubble or region lacking medical fluid in the cassette.

In some implementations, the backpriming step can happen automatically and very rapidly, without requiring action or approval by a healthcare provider, thereby creating only a very short delay or interruption of fluid flow to the patient (e.g., less than or equal to about 5 seconds or less than or equal to about 10 seconds), permitting substantially continuous infusion to occur even during the transition between the depletion of one fluid source and the start of infusion from another fluid source.

Terminology and Conclusion

Reference throughout this specification to “some implementations” or “an implementation” means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least some implementations. Thus, appearances of the phrases “in some implementations” or “in an implementation” in various places throughout this specification are not necessarily all referring to the same implementation and may refer to one or more of the same or different implementations. Furthermore, the features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more implementations.

As used in this application, the terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all the elements in the list.

Similarly, it should be appreciated that in this description of implementations, various features are sometimes grouped together in a single implementation, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Rather, inventive aspects lie in a combination of fewer than all features of any single disclosed implementation.

Implementations of the disclosed systems and methods may be used and/or implemented with local and/or remote devices, components, and/or modules. The term “remote” may include devices, components, and/or modules not stored locally, for example, not accessible via a local bus. Thus, a remote device may include a device which is physically located in the same room and connected via a device such as a switch or a local area network. In other situations, a remote device may also be located in a separate geographic area, such as, for example, in a different location, building, city, country, and so forth.

Methods and processes described herein may be embodied in, and partially or fully automated via, software code modules executed by one or more general and/or special purpose computers. The word “module” refers to logic embodied in hardware and/or firmware, or to a collection of software instructions, possibly having entry and exit points, written in a programming language, such as, for example, C or C++. A software module may be compiled and linked into an executable program, installed in a dynamically linked library, or may be written in an interpreted programming language such as, for example, BASIC, Perl, or Python. It will be appreciated that software modules may be callable from other modules or from themselves, and/or may be invoked in response to detected events or interrupts. Software instructions may be embedded in firmware, such as an erasable programmable read-only memory (EPROM). It will be further appreciated that hardware modules may be comprised of connected logic units, such as gates and flip-flops, and/or may be comprised of programmable units, such as programmable gate arrays, application specific integrated circuits, and/or processors. The modules described herein are preferably implemented as software modules, but may be represented in hardware and/or firmware. Moreover, although in some implementations a module may be separately compiled, in other implementations a module may represent a subset of instructions of a separately compiled program, and may not have an interface available to other logical program units.

In certain implementations, code modules may be implemented and/or stored in any type of computer-readable medium or other computer storage device. In some systems, data (and/or metadata) input to the system, data generated by the system, and/or data used by the system can be stored in any type of computer data repository, such as a relational database and/or flat file system. Any of the systems, methods, and processes described herein may include an interface configured to permit interaction with patients, health care practitioners, administrators, other systems, components, programs, and so forth.

A number of applications, publications, and external documents may be incorporated by reference herein. Any conflict or contradiction between a statement in the body text of this specification and a statement in any of the incorporated documents is to be resolved in favor of the statement in the body text.

Terms of equality and inequality (e.g., equal to, less than, greater than) are used herein as commonly used in the field, e.g., accounting for uncertainties present in measurement and control systems. Thus, such terms can be read as approximately equal, approximate less than, and/or approximately greater than. In other aspects of the invention, an acceptable threshold of deviation or hysteresis can be established by the pump manufacturer, the editor of the drug library, or the user of a pump.

While the implementations of the invention disclosed herein are presently considered to be preferred, various changes and modifications can be made without departing from the scope of the invention. Although described in the illustrative context of certain preferred implementations and examples, it will be understood by those skilled in the art that the disclosure extends beyond the specifically described implementations to other alternative implementations and/or uses and obvious modifications and equivalents. Thus, it is intended that the scope of the claims which follow should not be limited by the particular implementations described above. The scope of the invention is indicated in the appended claims, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.