Patent Description:
In traditional cardioplegia provided during open-heart surgery using a heart/lung machine, large volumes of crystalloid solution (as the carrier solution for the cardioplegia medication) are delivered to the patient, causing the hematocrit concentration in the blood to drop. This often leads to the need for hemoconcentrator use to remove the excess fluid and/or addition of packed red blood cells. Both approaches can cause complications in the patient. A preferred approach is to minimize the about of crystalloid medication given to still the heart.

<CIT> describes a system and method for precisely controlling the delivery of two fluids to a specific organ or region of a patient when one of the fluids breaks down the other fluid. The fluids are separately metered and are maintained in separate delivery lines until a point very near the target organ, preferably within twelve inches of the delivery site.

<CIT> describes a vacuum-assisted venous drainage reservoir for cardiopulmonary bypass surgery with both hard and soft shell reservoirs. The system utilizes a wall vacuum or other source of negative pressure to create a negative pressure via a regulator within a sealed hard shell reservoir, or within a sealed housing surrounding a soft shell reservoir. The addition of a negative pressure in the venous return line enables the use of smaller cannulas suitable for minimally invasive surgery.

<CIT> describes a combined cardiotomy and venous reservoir with filtration for autotransfusion of cardiotomy blood and venous blood during surgery and for postoperative wound site pleural drainage of shed blood for continued autotransfusion using the same unit. Vacuum regulation in the form of a manometer combined with a water seal are integral with the unit.

<CIT> describes a source of anticoagulated washing fluid in proportion to the bleeding rate which can be directed to the suction tip in such a way that the wound or surgical site is washed.

<CIT> describes combining a first biological fluid with a second biological fluid to produce a mixture of first and second biological fluids that may be adjusted and maintained to achieve a desired ratio. The apparatus includes subcomponent lines, valving means, pressure means, pressure indicator means, and load cells. The system may have numerous feedback components for accurately controlling the pressure, flow rates, and amount of fluid treated.

<CIT> describes a blood circulation apparatus includes a suction wand for receiving blood from a patient, a reservoir for collecting received blood, a conduit connecting the suction wand and the reservoir, an anticoagulant pump and line for introducing anticoagulant into the blood upstream of the reservoir, sensors for detecting liquid volume in the reservoir and for transmitting a corresponding volume signal, and a controller for regulating anticoagulant introduction in accordance with a predetermined program and as a function of the volume signal.

A heart/lung bypass machine system according to the present invention comprises the technical features as defined in independent claim <NUM>.

This document describes microplegia delivery systems. This document also describes systems that include a heart/lung machine and a microplegia delivery system.

The microplegia process provides small amounts of cardioplegia agents with each cardioplegia dose to a patient undergoing open-heart surgery. This is accomplished by directly delivering the cardioplegia agents into the blood-carrying portion of the cardioplegia circuit, without the additional crystalloid carrier solution of conventional cardioplegia systems that dilutes the blood.

The microplegia systems described herein use one or more syringe pumps that are controlled in a coordinated fashion to deliver the cardioplegia medications at prescribed dosages and rates at the proper/prescribed times. In some embodiments, the microplegia systems described herein link the individual flow rates of the syringe pumps with the actual, real-time measured flow rate of the cardioplegia blood flow. For example, as part of the heart/lung system setup procedure, the perfusionist can enter the prescribed drug concentrations, the desired ratio between the drugs and blood, and/or the expected dose (either dose volume or dose flow rate and duration) for each phase of the myocardial protection scheme that will take place during an open-heart surgery. This allows the perfusionist to use the appropriate amount of cardioplegia drug(s) for each phase, keeping the overall drug amount to a minimum.

The control system of the heart/lung system (or microplegia delivery system) will then operate/modulate the syringe pumps to deliver the appropriate amount of the drug(s) for the prescribed doses and/or the correct proportions of the drugs to blood for each delivery phase. In some embodiments, the control system will automatically calculate new flow rates and dose amounts for each phase of the open-heart surgery procedure, based on the set-up information entered by the perfusionist prior to the start of the procedure.

The microplegia delivery systems described herein also provide the ability for the user to change the drug-to-blood ratios on the fly using an adjustment knob and/or single keystroke. The control system will also adjust the drug delivery rate as the cardioplegia blood flow rates are changed without any additional user intervention. The microplegia systems described herein will also allow simultaneous starting and stopping of the syringe pump(s) (with cardioplegia medication) in conjunction with the starting and stopping of the cardioplegia blood pump, similar to a master/follower type of setup, so as to avoid accidental failure to coordinate starting/stopping of the pumps (the cardioplegia blood pump and the cardioplegia medication pumps).

During operation, the microplegia systems described herein will record the actual amount of blood and drug delivered for each phase of the myocardial protection scheme and make this available (e.g., by display) at the end of the procedure.

In addition, the microplegia systems described herein allow short half-life cardioplegia medications to be delivered essentially at the surgical field as opposed to at the heart/lung machine, thereby increasing the efficacy of such medications.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the present disclosure, suitable methods and materials are described herein. addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the present disclosure are set forth in the accompanying drawings and the description herein. Other features, objects, and advantages of the present disclosure will be apparent from the description and drawings, and from the claims.

Like reference numbers represent corresponding parts throughout.

This document describes microplegia delivery systems. This document also describes heart/lung machine systems that include a microplegia delivery system.

As shown in <FIG>, various types of medical procedures can be performed on a patient <NUM> while the patient <NUM> is connected to a life-sustaining heart/lung bypass machine system <NUM>. In this example, the patient <NUM> is undergoing open-heart surgery during which the heart <NUM> and lungs of the patient <NUM> are temporarily intentionally caused to cease functioning. Because the body of the patient <NUM> continues to have a metabolic need to receive a supply of circulating oxygenated blood during the medical procedure, however, the heart/lung bypass machine system <NUM> performs such functions. That is, as described further below, the heart/lung bypass machine system <NUM> is connected to the patient <NUM> and performs the functions of the heart <NUM> and lungs of the patient <NUM> so that the patient <NUM> stays alive and healthy during open-heart surgery. The heart/lung bypass machine system <NUM> can be used for many different types of medical procedures. For example, the medical procedures for which the heart/lung bypass machine system <NUM> can be used include, but are not limited to, coronary artery bypass grafts, heart valve repairs, heart valve replacements, heart transplants, lung transplants, ablation procedures, repair of septal defects, repair of congenital heart defects, repair of aneurysms, pulmonary endarterectomy, pulmonary thrombectomy, and the like.

The heart/lung bypass machine system <NUM> is typically set up and operated by a specially-trained clinician called a perfusionist. Perfusionists form part of the wider cardiovascular surgical team that includes cardiac surgeons, anesthesiologists, and nurses. During medical procedures using the heart/lung bypass machine system <NUM>, the perfusionist is tasked with many responsibilities, not the least of which is ensuring that the patient <NUM> is kept alive and healthy by operating the heart/lung bypass machine system <NUM> in a manner that maintains blood flow to the patient's tissues, and which regulates levels of oxygen and carbon dioxide in the blood of the patient <NUM>. Other responsibilities of the perfusionist include, but are not limited to, administering blood products, administering anesthetic agents or drugs, administering cardioplegia, measuring selected laboratory values (such as blood cell count), monitoring circulation, monitoring blood gases, surveilling anticoagulation, induction of hypothermia, and hemodilution. The responsibilities of the perfusionist are diverse, dynamic, and critically important to achieving successful outcomes of procedures performed on the patient <NUM> using the heart/lung bypass machine system <NUM>.

In the depicted example, the heart/lung bypass machine system <NUM> includes components and sub-systems such as a heart/lung machine <NUM>, an extracorporeal circuit <NUM>, one or more temperature control systems <NUM>, a blood monitoring system <NUM>, a perfusion data management system <NUM>, and a regional oximetry system <NUM>. Some types of procedures that use the heart/lung bypass machine system <NUM> may not require all of the components and sub-systems that are shown. Some types of procedures that use the heart/lung bypass machine system <NUM> may require additional components and/or sub-systems that are not shown.

The extracorporeal circuit <NUM> is connected to the patient <NUM>, and to the heart/lung machine <NUM>. Other systems, such as the temperature control system <NUM>, blood monitoring system <NUM>, and perfusion data management system <NUM> may also be arranged to interface with the extracorporeal circuit <NUM>. The extracorporeal circuit <NUM> is connected to the patient <NUM> at the patient's heart <NUM>. Oxygen-depleted blood (venous blood) from the patient <NUM> is extracted from the patient <NUM> at the patient's heart <NUM> using a venous catheter <NUM>. As described further below, the blood is circulated through the extracorporeal circuit <NUM> to receive oxygen and remove carbon dioxide. The oxygenated blood is then returned through the extracorporeal circuit <NUM> to the patient's heart <NUM> via an aortic cannula <NUM>.

The extracorporeal circuit <NUM> can include, at least, a venous tube <NUM> that is coupled to the venous catheter <NUM>, a blood reservoir <NUM>, a centrifugal pump <NUM>, an oxygenator <NUM>, an arterial filter <NUM>, one or more air bubble detectors <NUM>, and an arterial tube <NUM> that is coupled to the aortic cannula <NUM>. The venous catheter <NUM> and venous tube <NUM> are in fluid communication with the venous side of the circulatory system of the patient <NUM>. The venous tube <NUM> is also in fluid communication with an inlet to the reservoir <NUM>. An outlet from the reservoir <NUM> is connected by tubing to an inlet of the pump <NUM>. The outlet of the pump <NUM> is connected by tubing to an inlet of the oxygenator <NUM>. The outlet of the oxygenator <NUM> is connected by tubing to an inlet of the arterial filter <NUM>. An outlet of the arterial filter <NUM> is connected to the arterial tube <NUM>. One or more pressure transducers can be located along the arterial tube <NUM> to detect a heart/lung machine (HLM) system line pressure of the blood in the arterial tube <NUM>, which is measured by the heart/lung machine <NUM> and monitored by the perfusionist. The arterial tube <NUM> is connected to the arterial cannula <NUM>, which is in physical contact with the heart <NUM> and in fluid communication with the arterial side of the circulatory system of the patient <NUM>.

Briefly, the extracorporeal circuit <NUM> operates by removing venous, oxygen-depleted blood from the patient <NUM> via the venous catheter <NUM>, and depositing the venous blood in the reservoir <NUM> via the venous tube <NUM>. In some cases, gravity is used to cause the blood to flow or drain from the patient <NUM> to the reservoir <NUM>. In some cases, vacuum is used to assist the blood to flow from the patient <NUM> to the reservoir <NUM>. At least some amount of blood is intended to be maintained in the reservoir <NUM> at all times during the surgical procedure. Otherwise, if the reservoir <NUM> becomes empty, air could be pumped into the extracorporeal circuit <NUM>, and potentially into the vasculature of the patient <NUM>. Such a result would likely be catastrophic for the patient <NUM>. Accordingly, the perfusionist is tasked with visually monitoring the level of the blood in the reservoir <NUM>. In addition, level detectors can be included in conjunction with the reservoir <NUM> to issue an alarm in response to detection of low-level conditions within the reservoir <NUM>. Moreover, one or more air bubble detectors <NUM> can be located at various sites along the extracorporeal circuit <NUM>. Blood from the reservoir <NUM> is drawn by the pump <NUM>. While the depicted embodiment includes a one-time use centrifugal pump as the pump <NUM>, in some cases a peristaltic pump of the heart/lung machine <NUM> is used instead. The pressure generated by the pump <NUM> propels the blood through the oxygenator <NUM>. The perfusionist will adjust the pump <NUM> to operate as desired, while avoiding operational issues such as negative cavitation that could create micro air in the blood of the extracorporeal circuit <NUM>. In the oxygenator <NUM>, the venous blood is heated/cooled and then enriched with oxygen, and carbon dioxide is removed from the blood. The now oxygen-rich arterial blood exits the oxygenator <NUM>, travels through the arterial filter <NUM> to remove emboli, and is injected into the patient's heart <NUM> through the arterial tube <NUM> via the aortic cannula <NUM>.

The extracorporeal circuit <NUM> can also include tubing and other components for facilitating functions such as, but not limited to, drainage of blood accumulating in the heart of the patient <NUM>, providing surgical suction for maintaining visibility of the surgical field, delivery of cardioplegia solution to the blood/cardioplegia supply line <NUM> (or "table line") during the procedure, measuring blood parameters, removing air from the blood, hemoconcentration, drug addition, obtaining blood samples, heating and cooling of the blood, and the like.

During a surgical procedure using the heart/lung bypass machine system <NUM>, various vital signs of the patient <NUM> are measured and/or monitored. For example, a patient mean arterial pressure ("MAP") may be measured. The MAP of the patient <NUM> is a parameter that a perfusionist operating the heart/lung bypass machine system <NUM> will monitor in order to ensure that the heart/lung bypass machine system <NUM> is functioning as desired during the surgical procedure. In some cases, the MAP reading is displayed on a screen of an anesthesia system, and/or displayed on the operating room screen. If the MAP of the patient <NUM> is outside of a desired range, the perfusionist may make adjustments to the heart/lung bypass machine system <NUM> to improve the MAP of the patient <NUM>.

The heart/lung bypass machine system <NUM> also includes the heart/lung machine <NUM>. The heart/lung machine <NUM> is a complex system that includes multiple pumps, monitors, controls, user interfaces, alarms, safety devices, and the like, that are all monitored and operated/adjusted by the perfusionist during a surgical procedure. For example, the depicted heart/lung machine <NUM> includes an arterial pump <NUM> (which can be a drive system for a disposable centrifugal pump <NUM> as shown, or a peristaltic pump), a suction pump <NUM>, a vent/drainage pump <NUM>, a cardioplegia solution pump <NUM>, and a cardioplegia delivery pump <NUM>. The heart/lung machine <NUM> can also include, or be interfaced with, devices such as a tubing occluder, gas blender, and the like. The parameters of the heart/lung machine <NUM>, such as the rotational speed and other parameters of each of the pumps, are set and adjusted by the perfusionist. For example, the speed of the arterial pump <NUM> is adjusted to maintain a desirable level of blood in the reservoir <NUM>, and to provide a requisite level of blood circulation within the patient <NUM>.

The cardioplegia solution pump <NUM> conveys cardioplegia solution (including crystalloid solution as a carrier solution for one or more cardioplegia agents) that is sourced from a cardioplegia solution bag <NUM>. The cardioplegia solution exiting from the cardioplegia solution pump <NUM> is mixed with oxygenated blood that is conveyed by the cardioplegia delivery pump <NUM>. After the cardioplegia solution is mixed with the blood, the mixture in the blood/cardioplegia supply line <NUM> passes through a heat exchanger <NUM> that can be used/controlled to heat or cool the mixture of cardioplegia solution and blood to a desired temperature. After the passing through the heat exchanger <NUM>, the mixture of cardioplegia solution and blood in the blood/cardioplegia supply line <NUM> is injected into the heart <NUM> in either an antegrade or retrograde manner.

In some cases, the cardioplegia solution(s) can be administered to the patient <NUM> in accordance with three phases: (i) an induction dose, (ii) maintenance doses, and (iii) a reperfusion or reanimation dose. The induction dose (typically including potassium) is administered to arrest the heart <NUM>. Maintenance doses are thereafter administered periodically (e.g., every <NUM> minutes) during the surgery to nourish the tissues of the heart <NUM>. The reperfusion or reanimation dose is administered near the end of the surgery to warm and restart the heart (e.g., to flush out potassium).

The heart/lung bypass machine system <NUM> also includes one or more temperature control systems <NUM>. In a first aspect, the temperature control system(s) <NUM> is/are used to heat and cool the patient's blood in the oxygenator <NUM> via a heat exchanger. Additionally, the temperature control systems <NUM> is used with the heat exchanger <NUM> to heat or cool the cardioplegia solution (and blood) being delivered to the patient <NUM> via the blood/cardioplegia supply line <NUM>. In general, the temperature control system(s) <NUM> is/are used in cooling modes during the procedure (to reduce metabolic demands), and subsequently used to warm the blood and/or cardioplegia solution when the surgical procedure is nearing its end. The perfusionist is tasked with monitoring and adjusting the temperature control system(s) <NUM> as needed during the surgical procedure.

The heart/lung bypass machine system <NUM>, as depicted, also includes the blood monitoring system <NUM>. The blood monitoring system <NUM> is used to monitor the extracorporeal blood of the patient <NUM> during the surgical procedure. Parameters being monitored can include, but are not limited to, pH, pCO<NUM>, pO<NUM>, K+, temperature, SO<NUM>, hematocrit, hemoglobin, base excess, bicarbonate, oxygen consumption and oxygen delivery. The perfusionist is tasked with monitoring the blood monitoring system <NUM> during the surgical procedure. In some cases, the perfusionist will need to adjust other components or subsystems of the heart/lung bypass machine system <NUM> in response to readings from the blood monitoring system <NUM>.

The heart/lung bypass machine system <NUM>, as depicted, also includes the perfusion data management system <NUM> and the regional oximetry system <NUM>. These systems can also be used by the perfusionist to monitor the status of the patient <NUM> and/or the status of the heart/lung bypass machine system <NUM> during surgical procedures.

From the above description, it can be observed and understood that the perfusionist is tasked with a vast amount of very important responsibilities during a surgical procedure using the heart/lung bypass machine system <NUM>.

To centralize and automate some of the tasks of the perfusionist pertaining to cardioplegia delivery, this disclosure describes a system of one or more syringe pumps for delivering cardioplegia solutions that can be included as part of the heart/lung bypass machine system <NUM>, or as a stand-alone system.

As shown in <FIG>, the heart/lung bypass machine system <NUM> can include a system of one or more syringe pumps <NUM> to deliver one or more different types of cardioplegia agents into the oxygenated blood returning to the heart <NUM> of the patient <NUM> via the blood/cardioplegia supply line <NUM>. The system of syringe pumps <NUM> can be pole-mounted, arranged on one or more racks, positioned on one or more carts, and combinations thereof.

The depicted system of syringe pumps <NUM> includes three syringe pumps 170a, 170b, 170c (or 170a-c collectively). However, in general any number of syringe pumps <NUM> can be used (e.g., one, two, three, four, five or more) - corresponding to the number of cardioplegia agents to be used during the surgical procedure.

In some embodiments, each syringe pump 170a, 170b, and 170c of the system of syringe pumps <NUM> can be individually in electrical signal communication with the programmed control system(s) of the heart/lung machine <NUM>. Accordingly, in some such embodiments the operations of each syringe pump 170a, 170b, and 170c can be individually controlled by the control system of the heart/lung machine <NUM>, and thereby controlled in response to pre-programmed algorithms and/or user set-up parameters and other user inputs. For example, each syringe pump 170a, 170b, and 170c can be individually controlled (by the control system of the heart/lung machine <NUM>) to start operating, to inject its cardioplegia agent at a particular flow rate, to inject a particular amount of the cardioplegia agent, to operate for a particular amount of time, and/or to stop operating. Moreover, each syringe pump 170a, 170b, and 170c can be individually controlled in coordination with the other components the heart/lung machine <NUM> (e.g., in coordination with the cardioplegia delivery pump <NUM>) and taking into account which phase the surgical procedure in is (e.g., beginning, middle, or end). Additionally, or alternatively, in some embodiments the system of syringe pumps <NUM> is configured to be controlled/operated independently of the operations of the heart/lung machine <NUM>.

In some embodiments, a dedicated user interface for the system of syringe pumps <NUM> is included by which a perfusionist can enter inputs to control the system of syringe pumps <NUM>. Alternatively, or additionally, in some embodiments the user interface(s) of the heart/lung machine <NUM> can be used to receive user inputs to control the system of syringe pumps <NUM>.

The depicted system of syringe pumps <NUM> can be utilized instead of the cardioplegia solution pump <NUM> that conveys cardioplegia solution (including crystalloid) from the cardioplegia solution bag <NUM> as described above in reference to <FIG>. The use of the system of syringe pumps <NUM> can allow the cardioplegia agents to be administered to the patient <NUM> without requiring the cardioplegia agents to be mixed/diluted with crystalloid. Accordingly, by using the system of syringe pumps <NUM>, the blood of the patient <NUM> will advantageously not become as diluted as if the conventional cardioplegia system of <FIG> is used.

The blood/cardioplegia supply line <NUM> of the extracorporeal circuit <NUM> shown in <FIG> further includes a temperature sensor <NUM> (located after the heat exchanger <NUM>), an air bubble trap <NUM>, and a pressure transducer <NUM>. The temperature sensor <NUM> allows the perfusionist (and/or the control system of the heart/lung machine <NUM>) to monitor and/or control the temperature of the oxygenated blood prior to the infusion of the cardioplegia agent(s) from the syringe pumps 170a-c. The bubble trap <NUM> removes air bubbles that may be entrained in the blood/cardioplegia mixture before reaching the heart <NUM>. The pressure transducer <NUM> can be used by the perfusionist (and/or the control system of the heart/lung machine <NUM>) to monitor the pressure of the blood/cardioplegia mixture in the blood/cardioplegia supply line <NUM>. The pressure transducer <NUM> can facilitate the ability to control the flow rate of the mixture of cardioplegia solution and blood to maintain a desired line pressure in the blood/cardioplegia supply line <NUM> for desired cardioplegia dose delivery.

The system of multiple syringe pumps <NUM> advantageously allows the individual cardioplegia agents to be delivered (injected) into the blood/cardioplegia supply line <NUM> at different points and with independent drug delivery rate control along the blood/cardioplegia supply line <NUM> (rather than at a single point as with the conventional cardioplegia delivery system of <FIG>). For example, in the depicted embodiment the syringe pumps 170b and 170c inject cardioplegia agents into the blood/cardioplegia supply line <NUM> after the heat exchanger <NUM> but prior to the bubble trap <NUM>, and the syringe pump 170a injects its cardioplegia agent after the bubble trap <NUM> (closer to the patient <NUM> than the syringe pumps 170b and 170c). This ability to inject cardioplegia agents at different points along the blood/cardioplegia supply line <NUM>, and to inject a cardioplegia agent close to the patient is advantageous for the reasons described herein.

<FIG> depicts a schematic diagram of a portion of the extracorporeal circuit <NUM> of <FIG>, including the oxygenator <NUM>, the cardioplegia pump <NUM>, the blood/cardioplegia supply line <NUM>, the heat exchanger <NUM>, the temperature probe <NUM>, the bubble trap <NUM>, the pressure transducer <NUM>, and including the three syringe pumps 170a, 170b, and 170c.

Each syringe pump 170a-c of the system <NUM> is an infusion device used to deliver cardioplegia agents contained within installed syringes in a controllable manner and at a precise flow rate. Each syringe pump 170a-c can have a receiver portion configured to removably receive a syringe containing a cardioplegia agent, a drive mechanism controllably operable for gradually driving the plunger of the syringe to eject the cardioplegia agent at a prescribed flow rate, and, optionally, a user interface for receiving inputs from the perfusionist.

A syringe with a cardioplegia agent can be installed into each of the syringe pumps 170a-c prior to beginning the surgical procedure. During installation of the syringes in the syringe pumps 170a-c, the tips of the syringes are connected to tubing exiting the syringe pump 170a-c via a fluid-secure means such as a luer locking or compression fitting mechanism. The tubing is in fluid communication with the blood/cardioplegia supply line <NUM>, such as after (downstream of) the temperature probe <NUM>.

The drive mechanism of each syringe pump 170a-c can control the on/off and flow rate from its syringe based on control signals received from the heart/lung machine <NUM> and/or based on input(s) from the perfusionist. For example, in some embodiments the perfusionist can input desired flow rates and/or agent-to-blood ratios for each of the cardioplegia agents. In some embodiments, the perfusionist can input such prescribed flow rates and/or agent-to-blood ratios for each syringe pump 170a-c for one or more time periods or phases occurring during the surgical procedure (e.g., the induction dose phase, the maintenance dose phase, and the reperfusion or reanimation dose phase).

In some embodiments, the perfusionist can program or control the flow rate of each of the syringe pumps 170a-c of the system individually or collectively. In some embodiments, the syringe pump 170a-c flow rates can be linked to automatically modulate based on the actual flow rate of the cardioplegia delivery pump <NUM>. For example, in some embodiments the perfusionist can set each of the syringe pumps 170a-c to operate at a flow rate that is a percentage corresponding to the actual flow rate of the cardioplegia delivery pump <NUM>. Alternatively, the perfusionist can set up the syringe pumps170a-c to operate at a flow rate that is a particular ratio to the actual flow rate of the cardioplegia blood delivery pump <NUM>. Different percentages or ratios for each of the syringe pumps 170a-c can be pre-programmed by the perfusionist for each phase of the surgery (e.g., the induction dose phase, the maintenance dose phase, and the reperfusion or reanimation dose phase). In such a case, the control system of the heart/lung machine <NUM>, and/or the syringe pump 170a-c systems, can make automatic adjustments to maintain the pre-set ratios established by the perfusionist's input.

Each syringe pump 170a-c of the system is in fluid communication with the blood/cardioplegia supply line <NUM> at a separate point, spaced longitudinally apart from each other. For example, <FIG> depicts syringe pumps 170b and 170c in fluid communication with the blood/cardioplegia supply line <NUM> between the temperature sensor <NUM> and the bubble trap <NUM>, and a third syringe pump 170a in fluid communication with the blood/cardioplegia supply line <NUM> between the pressure transducer <NUM> and the patient <NUM>. In this manner, cardioplegia agents that may have a short medically active duration, (e.g., Adenocaine, etc.) can be advantageously infused into the blood/cardioplegia supply line <NUM> close to the patient <NUM> (e.g., using the syringe pump 170a). This increases the efficacy of such cardioplegia agents to the patient <NUM>.

<FIG> schematically depicts an alternative drug delivery system <NUM> synchronized with the HLM. The drug delivery system <NUM> can be used in conjunction with the cardioplegia system arrangement (e.g., the arrangements of <FIG>, <FIG>, and/or <NUM>) or by itself without another cardioplegia system arrangement.

The drug delivery system <NUM> includes a syringe pump <NUM>. While a single syringe pump <NUM> is depicted, it should be understood that two, three, or more than three syringe pumps <NUM> can be included in the system <NUM> in some embodiments. The syringe pump <NUM> is configured to deliver one or more drug solutions as described above in reference to the syringe pumps 170a-c. The syringe pump <NUM> can include any of the operational features that are described in reference to the syringe pumps 170a-c. In addition, the syringe pump <NUM> is in two-way data communication with the control system of the heart/lung machine <NUM> (<FIG>). Accordingly, the syringe pump <NUM> can be controlled by the control system of the heart/lung machine <NUM> to operate in any of the manners described above in reference to the syringe pumps 170a-c.

The syringe pump <NUM> delivers one or more drug solutions to the venous blood reservoir <NUM>. In the venous blood reservoir <NUM>, the one or more drug solutions delivered from the syringe pump <NUM> is/are mixed with the venous blood of the patient <NUM>. The mixture then exits the venous blood reservoir <NUM>, passes through the arterial pump <NUM>, the oxygenator <NUM>, and the arterial filter <NUM> before being returned to the patient <NUM>.

A perfusionist user of the drug system <NUM> will be able to enter into a user interface a target set point of the concentration (or dosage) of the one or more drug solutions to be delivered from the syringe pump <NUM>. In some embodiments, the control system of the heart/lung machine <NUM> (or the syringe pump <NUM>) can determine a flow rate for the syringe pump <NUM> to operate at to attain the targeted concentration of the one or more drug solutions. Then, during operation, the syringe pump <NUM> can be controlled to operate accordingly. Target set points can also be adjusted during operation of the drug delivery system <NUM>. The entry of the target set points can be stored in the memory of the control system of the heart/lung machine <NUM> and/or the control system of the syringe pump <NUM>.

For some medications to be delivered by the syringe pump <NUM>, the delivery rate can be linked to the arterial blood flow rate either directly or inversely. For other medications, the delivery rate can be controlled independent of the arterial blood flow rate. In either case, the syringe pump <NUM> can be controlled to stop drug delivery when arterial flow rate is stopped (e.g., in response to an alarm situation such as an alarm from a detection of air in the arterial line <NUM>). In some embodiments, the syringe pumps 170a-c can be stopped directly in response to an alarm of the heart/lung machine <NUM> (rather than in response to a stoppage of the arterial pump). This is a safety feature that makes the control communications link to heart/lung machine <NUM> very useful. In one example, when weaning a patient from extracorporeal membrane oxygenation (ECMO), heparin delivered by the syringe pump <NUM> can be increased to reduce risk of blood clotting, and reduced/discontinued after the patient is off ECMO.

Analogous to the cardioplegia system using the syringe pumps 170a-c as described above, when the syringe pump <NUM> delivers medication (e.g., non-cardioplegia therapeutic agents) to the blood, the dose amount and timing parameters (e.g., start time and stop time) are stored in the memory of the control system of the heart/lung machine <NUM> and/or the control system of the syringe pump <NUM>. The concentration can also be stored. These data can be later retrieved/read and used as desired.

The drug delivery system <NUM> can be used to deliver a bolus of one or more medications from the syringe pump <NUM>. Data describing the delivery of such bolus amounts are stored in the memory of the control system of the heart/lung machine <NUM> and/or the control system of the syringe pump <NUM>.

In some embodiments, the user will be able to set a low volume alert level for each drug/syringe in the syringe pump <NUM>. The control system of the heart/lung machine <NUM> and/or the control system of the syringe pump <NUM> can keep track of the amount of medication pumped from each syringe. An alert/alarm can be generated when the remaining volume in the syringe is at or below the low volume alert level. In some embodiments, expired time can also be used as a basis for generating an alert/alarm. Accordingly, the amount of time remaining prior to running out of the medication in the syringe can be provided and/or used as a basis for generating an alert/alarm.

In some embodiments, the delivery of the medication from the syringe pump <NUM> can be at least somewhat based on the mean arterial pressure (MAP) during the procedure. For example, in some embodiments the delivery of a vasodilator from the syringe pump <NUM> can be started when the MAP is above a user-established set point, and stopped when the MAP falls below another user-established set point. In another example, in some embodiments the delivery of a vasopressor can be started when the MAP is below a user-established set point, and stopped when the MAP is above another user-established set point. In still another example, in some embodiments the delivery of the medication from the syringe pump <NUM> can be titrated based on continuous monitoring of MAP, such as a rate of change of MAP to a desired set point of pressure.

The system can also track and display the time since the last cardioplegia dose. In some embodiments, this timer is automatically reset to zero when the next dose is started.

During operation, the system can record/track the actual amount of blood and cardioplegia agent delivered for each phase of the myocardial protection scheme and make this available at the end of the procedure. For example, volumetric data for each cardioplegia agent administered, by each phase, can be displayed at the end of the procedure, and/or during the procedure.

In some embodiments, the perfusionist can preprogram the myocardial protection scheme into the system (including, for example, prescribed cardioplegia drug-to-blood ratios for each cardioplegia drug and delivery/surgery phase). Then, the system can automatically (or semi-automatically) control the flow rate delivery of the cardioplegia agents in accordance with the program. Moreover, such programs can be saved and reused.

In some embodiments, the system can selectively control/maintain cardioplegia line pressure(s) using pressure sensor feedback as directed by the user.

The system can facilitate automatic simultaneous starting/stopping of syringe pump(s) with the starting/stopping of the cardioplegia blood pump.

In some embodiments, the system can automatically calculate cardioplegia drug flow rates for each delivery phase.

The system can allow the perfusionist a convenient way to change the cardioplegia drug-to-blood ratio on the fly during a surgery.

In some embodiments, a local control module would be responsible for configuring and controlling each syringe pump using a communications link for each syringe pump. The syringe pump-based controls would be disabled, only the local display of the local control module would be active. In some such embodiments, the syringe pumps and the local control module are a stand-alone system (not needing to be interfaced with the heart/lung machine).

In some embodiments, the syringe pumps cannot be operated independently of the heart/lung machine. For example, in some embodiments the clinician cannot enter configuration parameters or commands directly on the syringe pumps. Instead, all commands must come from the heart/lung machine. The only way the syringe pumps would be operational is when they are connected to the heart/lung machine via the local controller. Furthermore, in some embodiments the syringe pumps mechanisms can be embedded in a housing to prevent the appearance of being standalone syringe pumps that could operate independently of the heart/lung machine.

In some embodiments, all of the syringe pump mechanisms are mounted in a common housing. Each syringe pump can have a display, a stop button and the required user interface to be able to load and unload a syringe.

In some embodiments, a local control module of the syringe pump system can display a fluid temperature when a temperature probe is linked to the local control module.

In some embodiments, setup of the syringe pump system can be accomplished using multiple different approaches. A first method can be to access the cardioplegia setup screen from the heart/lung machine central user interface monitor (e.g., with an on-screen keyboard). The user will be able to create multiple setups, allowing a specific setup for each procedure and/or surgeon. These can be saved and reloaded as needed. This would then be downloaded to the local cardioplegia controller during setup. In some embodiments, a majority of the setup information will be also be available via the display of the local controller. For example, the user could be able to edit everything but the drug name. In other cases, setup information pertaining to a syringe pump system can be electronically transferred from one heart/lung machine to another heart/lung machine.

In some embodiments, the user will be able to set a low volume alert level for each drug/syringe. The cardioplegia controller or heart/lung machine control system will keep track of the amount of cardioplegia agent pumped from each syringe. An alert/alarm will be generated when the remaining volume in the syringe is at or below the low volume alert level.

In some embodiments, the control system of the heart/lung machine <NUM> and/or the control system of the drug delivery system can include (or operate) a timer that will be used to issue a reminder to collect a blood sample for an activated clotting time (ACT) lab test. In some embodiments, the control system of the heart/lung machine <NUM> and/or the control system of the cardioplegia delivery system can allow for entry, via a user interface, ACT lab test results. In some such embodiments, the control system of the heart/lung machine <NUM> and/or the control system of the drug delivery system can suggest a dose adjustment based on a user-established ACT target value and one or more patient parameters (patient weight, body surface area, or calculated circulating volume, for example). User-established ACT target values can be adjusted during a procedure. All such set-points, test results, and the like can be stored in the memory of the control system of the heart/lung machine <NUM> and/or the control system of the drug delivery system.

In some embodiments, at the end of a patient treatment procedure using the systems described herein, the control system of the heart/lung machine <NUM> and/or the control system of the drug delivery system can provide the ability to view all types of drugs and delivered doses/concentrations that occurred during the procedure. In some embodiments, the control system of the heart/lung machine <NUM> and/or the control system of the drug delivery system is configured to communicate such information to a third party (e.g., a central database, data management system, etc.) during and/or at the end of the procedure.

In some embodiments, each syringe pump includes a local user interface. In some cases, each local user interface would be identified with a specific syringe pump by having a colored light on the syringe pump that matches the background color of the local user interface. For example, in some embodiments it would use the same color scheme used by other pumps to identify the link between local control and syringe pump. In some embodiments, the local user interface(s) would display one or more of the following types of information: drug name, drug flow rate, volume(s) delivered, time duration of deliveries, mean arterial pressure, soft keys for control functions such as start/stop and bolus delivery initiation, delivery ration between arterial flow and drug flow, adjustment inputs (e.g., up/down arrows or a knob) for altering delivery ratio(s) and other set points, notifications (e.g., low drug remaining, no drug remaining, etc.).

In some embodiments, the systems described herein can include one or more timers that can display, for example, the time expired since the last dose. In some such embodiments, notifications can be provided from the systems that are based on values of the timer(s), such as but not limited to, the time expired since the last dose of one or more cardioplegia agents.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of the present disclosure or of the invention as defined by the appended claims, but rather as descriptions of features specific to particular embodiments of the present disclosure.

Claim 1:
A heart/lung bypass machine system (<NUM>, <NUM>) comprising:
a venous blood reservoir (<NUM>);
an oxygenator (<NUM>); and
an arterial blood pump (<NUM>, <NUM>) configured to pump blood from the venous blood reservoir (<NUM>) to the oxygenator (<NUM>), the arterial blood pump (<NUM>, <NUM>) configured to have a speed that is adjustable to maintain a desirable level of blood in the venous blood reservoir (<NUM>) and to provide a requisite level of blood circulation within a patient (<NUM>);
characterized in that the system comprises
a first syringe pump (<NUM>) configured to deliver a first drug agent to the venous blood reservoir (<NUM>); and
a controller comprising a hardware processor and computer memory, the controller in electrical signal communication with the arterial blood pump and the first syringe pump,
wherein the controller is configured to modulate an operational speed of the first syringe pump based on an actual speed of the arterial blood pump (<NUM>, <NUM>).