Microplegia Delivery System

Abstract

To provide a microplegia delivery system for providing a small amount of cardioplegic substance to a patient to under go open-heart surgery, along with each cardioplegic dose.SOLUTION: Microplegia systems use syringe pumps 170 that are controlled in a coordinated fashion to deliver cardioplegia medications during an open-heart surgery at the prescribed dosages and / or rates. The microplegia systems link the delivery rate of the syringe pumps with the delivery rate of the cardioplegia blood flow rate. A perfusionist can enter prescribed drug concentrations, desired ratios between drug and blood, and the expected dose for each phase of the myocardial protection scheme that will take place during the open-heart surgery. Additionally, or alternatively, the syringe pump systems described herein can also be used to deliver other non-cardioplegia types of therapeutic substances.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This document relates to heart-lung machines, including microplegia systems. [Background technology]

[0002] In traditional cardioplegia provided during open-heart surgery using a cardiopulmonary bypass machine, large volumes of crystalloid fluid are delivered to the patient (as a carrier solution for cardioplegic medication), resulting in a decrease in blood hematocrit. This often leads to the need for the use of a hemoconcentrator to remove excess fluid and / or additional packed red blood cells. Both approaches can result in complications for the patient. The preferred approach is to minimize the use of crystalloid medications given to sedate the heart. Summary of the Invention

[0003] This document describes a microplegia delivery system. This document also describes a system that includes a heart-lung machine and a microplegia delivery system.

[0004] The Microplegia process provides a small amount of cardioplegic agent with each cardioplegic dose to patients undergoing open heart surgery. This is achieved by delivering the cardioplegic agent directly to the blood-carrying portion of the cardioplegic circuit without the added crystalloid carrier solution of conventional cardioplegic systems, which thins the blood.

[0005] The microplegia systems described herein use one or more syringe pumps controlled in a coordinated manner to deliver cardioplegic drugs at appropriate / prescribed times, in prescribed dosages, and at prescribed rates. 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 cardioplegic blood. For example, as part of the cardiopulmonary system setup procedure, the perfusionist can input the prescribed drug concentration, desired drug-to-blood ratio, and / or predicted dose (either dose or dose rate and duration) for each phase of the cardioplegic scheme that will be performed during open-heart surgery. This allows the perfusionist to use the appropriate amount of cardioplegic drug for each phase, keeping overall drug volume to a minimum.

[0006] The control system of the heart-lung system (or microplegia delivery system) then operates / adjusts the syringe pump to deliver the appropriate amount of drug for the prescribed dose and / or the correct ratio of drug to the blood for each delivery phase. In some embodiments, the control system will automatically calculate new flow rates and doses for each phase of the open-heart surgery treatment based on setup information entered by the perfusionist prior to the start of treatment.

[0007] The microplegia delivery system described here also provides the user with the ability to change the drug-to-blood ratio on the fly using an adjustment knob and / or a single keystroke. The control system will also adjust the drug delivery ratio as the cardioplegic blood flow ratio changes, without any additional user intervention. The microplegia system described here also allows for simultaneous starting and stopping of the syringe pump (with cardioplegic drug) in conjunction with starting and stopping the cardioplegic blood pump, similar to a master / follower type setup, to avoid unexpected failures in coordinating the starting / stopping of the pumps (cardioplegic blood pump and cardioplegic drug pump).

[0008] During operation, the Microplegia system described herein will record the actual volume of blood and drug delivered for each phase of the cardioplegia scheme and make this available (by display) at the end of treatment.

[0009] Additionally, the microplegia system described herein allows for short half-life cardioplegic agents to be delivered essentially at the surgical field as opposed to a cardiopulmonary bypass machine, thereby increasing the effectiveness of such agents.

[0010] 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 belongs. Although methods and materials similar or equivalent to those described herein can be used to practice the present invention, suitable methods and materials are described herein. All publications, patent applications, patents, and other documents mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. Furthermore, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0011] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description herein. Other features, objects, and advantages of the invention will become apparent from the description, drawings, and claims. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic illustration of a patient undergoing open heart surgery while being supported using a heart-lung machine and an extracorporeal circuit, according to some embodiments provided herein. [Figure 2] FIG. 2 is a schematic illustration of a patient undergoing open heart surgery while being supported using the system of FIG. 1, except that an exemplary Microplegia system is used rather than the conventional cardioplegia system shown in FIG. 1. [Figure 3]FIG. 3 is a schematic diagram of the exemplary microplegia system of FIG. 2 and relevant portions of the heart-lung machine and extracorporeal circuit of FIG. 2. [Figure 4] FIG. 4 is a schematic diagram of an exemplary drug delivery system associated with the heart-lung machine and associated portions of the extracorporeal circuit of FIG.

[0013] Like numbers refer to corresponding parts throughout. DETAILED DESCRIPTION OF THE INVENTION

[0014] This document describes a microplegia delivery system. This document also describes a heart-lung machine system that includes the microplegia delivery system.

[0015] As shown in FIG. 1 , various types of medical treatments are administered to patient 10 while patient 10 is connected to life-sustaining cardiopulmonary bypass system 100. In this example, patient 10 is undergoing open-heart surgery, during which patient 10's heart 12 and lungs are intentionally temporarily stopped from functioning. Because patient 10's body continues to have a metabolic need to receive a circulating supply of oxygenated blood during medical treatment, cardiopulmonary bypass system 100 performs such functions. That is, as described further below, during open-heart surgery, cardiopulmonary bypass system 100 is connected to patient 10 and performs the functions of patient 10's heart 12 and lungs to keep patient 10 alive and healthy. Cardiopulmonary bypass system 100 can be used for many different types of medical treatments. For example, medical procedures that may use the cardiopulmonary bypass system 100 may include, but are not limited to, coronary artery bypass grafts, heart valve repair, heart valve replacement, heart transplants, lung transplants, ablation procedures, septal defect repairs, congenital heart defect repairs, aneurysm repairs, pulmonary endarterectomies, pulmonary thrombectomy, and the like.

[0016] Cardiopulmonary bypass system 100 is typically set up and operated by a specially trained clinician called a perfusionist. Perfusionists form part of a broader cardiovascular surgical team that includes cardiac surgeons, anesthesiologists, and nurses. During medical treatment using cardiopulmonary bypass system 100, perfusionists are tasked with many responsibilities, most importantly, ensuring that patient 10 is alive and healthy by operating cardiopulmonary bypass system 100 in a manner that maintains blood flow to the patient's tissues, regulating oxygen and carbon dioxide levels in the patient's 10 blood. Other responsibilities of perfusionists include, but are not limited to, administering blood products, administering anesthetics or medications, administering cardioplegia, measuring selected clinical values ​​(such as blood counts), monitoring circulation, monitoring blood gases, anticoagulation monitoring, inducing hypothermia, and hemodilution. The responsibilities of the perfusionist are varied, dynamic, and critical to achieving a successful outcome of the treatment administered to patient 10 using cardiopulmonary bypass system 100.

[0017] In the depicted example, cardiopulmonary bypass system 100 includes components and subsystems such as a heart-lung machine 110, an extracorporeal circuit 120, one or more temperature control systems 130, a blood monitoring system 140, a perfusion data management system 150, and a regional oximetry system 160. Some types of treatments using cardiopulmonary bypass system 100 may not require all of the components and subsystems shown. Some types of treatments using cardiopulmonary bypass system 100 may require additional components and / or subsystems not shown.

[0018] The extracorporeal circuit 120 is connected to the patient 10 and the heart-lung machine 110. A temperature control system 130, a blood monitoring system 140, and a perfusion data management system 150 may also be configured to interface with the extracorporeal circuit 120. The extracorporeal circuit 120 is connected to the patient 10 at the patient's heart 12. Oxygen-depleted blood (venous blood) from the patient 10 is extracted from the patient 10 at the patient's heart 12 using a venous catheter 121. As described further below, the blood circulates through the extracorporeal circuit 120 to receive oxygen and remove carbon dioxide. The oxygenated blood is returned to the patient's heart 12 through the extracorporeal circuit 120 via an aortic cannula 129.

[0019] The extracorporeal circuit 120 may include at least an venous line 122 coupled to a venous catheter 121, an arterial tubing 127 connected to a blood reservoir 123, a centrifugal pump 124, an oxygenator 125, an arterial filter 126, one or more air bubble detectors 128, and an aortic cannula 129. The venous catheter 121 and the venous line 122 are fluidly connected to the venous side of the patient's circulatory system. The venous line 122 is also fluidly connected to an inlet to the reservoir 123. An outlet from the reservoir 123 is connected by tubing to an inlet of the pump 124. An outlet of the pump 124 is connected by tubing to an inlet of the oxygenator 125. An outlet of the oxygenator 125 is connected by tubing to an inlet of the arterial filter 126. An outlet of the arterial filter 126 is connected to the arterial line 127. One or more pressure transducers may be positioned along the arterial line 127 to detect the heart-lung machine (HLM) system line pressure of blood in the arterial line 127, which is measured by the heart-lung machine 110 and monitored by a perfusionist. The arterial line 127 is connected to an arterial cannula 129, which is in physical contact with the heart 12 and in fluid communication with the arterial side of the circulatory system of the patient 10.

[0020] Temporarily, the extracorporeal circuit 120 removes venous, oxygen-depleted blood from the patient 10 via a venous catheter 121 and places the venous blood in a reservoir 123 via an intravenous line 122. In some cases, gravity is used to cause blood to flow or drain from the patient 10 to the reservoir 123. In some cases, a vacuum is used to assist the flow of blood from the patient 10 to the reservoir 123. At least some amount of blood is intended to be maintained in the reservoir 123 at all times during the surgical procedure. Otherwise, the reservoir 123 may empty, and air may be introduced into the extracorporeal circuit 120 and potentially into the vasculature of the patient 10. Such consequences could be disastrous for the patient 10. Therefore, the perfusionist is tasked with visually monitoring the level of blood in the reservoir 123. Additionally, a level detector may be included with the reservoir 123 to sound an alarm in response to detecting a low-level condition in the reservoir 123. Additionally, one or more air bubble detectors 128 can be positioned at various locations along the extracorporeal circuit 120. Blood from the reservoir 123 is pumped by a pump 124. While the depicted embodiment includes a single-use centrifugal pump as the pump 124, in some cases, a peristaltic pump from the heart-lung machine 110 is used instead. The pressure generated by the pump 124 forces the blood through an oxygenator 125. A perfusionist adjusts the pump 124 to perform as desired while avoiding operational issues such as harmful cavitation, which can create tiny air pockets in the blood of the extracorporeal circuit 120. In the oxygenator 125, the venous blood is warmed / cooled, then enriched with oxygen and carbon dioxide is removed from the blood. The oxygen-rich arterial blood exits the oxygenator 125, travels through an arterial filter 126 to remove emboli, and is infused into the patient's heart 12 through an arterial tubing 127 via an aortic cannula 129.

[0021] The extracorporeal circuit 120 may also include tubing and other components that facilitate functions such as, but not limited to, draining blood that accumulates in the patient's 10 heart, providing surgical suction to maintain visibility of the surgical field, delivering cardioplegic solution to a blood / cardioplegic supply line 135 (or "table line") during treatment, measuring blood parameters, removing air from the blood, hemoconcentrating, adding medication, taking blood samples, warming and cooling the blood, and the like.

[0022] During a surgical procedure using cardiopulmonary bypass system 100, various vital signs of patient 10 are measured and / or monitored. For example, the patient's mean arterial pressure ("MAP") may be measured. The patient's 10 MAP is the parameter by which the perfusionist operates cardiopulmonary bypass system 100 to ensure that the system functions as desired during the surgical procedure. In some cases, the MAP measurement is displayed on an anesthesia system screen and / or on an operating room screen. If the patient's 10 MAP is outside of a desired range, the perfusionist makes adjustments to cardiopulmonary bypass system 100 to improve the patient's 10 MAP.

[0023] Cardiopulmonary bypass system 100 also includes a heart-lung machine 110, a complex system including multiple pumps, monitors, controls, user interfaces, alarms, safety devices, and the like, all monitored and operated / regulated by a perfusionist during a surgical procedure. For example, the depicted heart-lung machine 110 includes an arterial pump 111 (which may be a disposable centrifugal pump 124, as shown, or a drive system for a peristaltic pump), a suction pump 112, a vent / drainage pump 113, a cardioplegia solution pump 114, and a cardioplegia solution delivery pump 115. Heart-lung machine 110 may also include or interface with devices such as a tubing occluder, a gas blender, and the like. Parameters of the heart-lung machine 110, such as rotational speed, and other parameters of each of the pumps, are set and adjusted by a perfusionist. For example, the speed of the arterial pump 111 is adjusted to maintain a desired level of blood in the reservoir 123 and provide the required level of blood circulation within the patient 10.

[0024] Cardioplegia solution pump 114 delivers cardioplegia solution (containing crystalloid solution as a carrier solution for one or more cardioplegic agents) supplied from cardioplegia solution bag 132. The cardioplegia solution exiting cardioplegia solution pump 114 is mixed with oxygenated blood delivered by cardioplegia solution delivery pump 115. After the cardioplegia solution is mixed with the blood, the mixture in blood / cardioplegia solution supply line 135 passes through heat exchanger 134, which can be used / controlled to warm or cool the cardioplegia solution and blood mixture to a desired temperature. After passing through heat exchanger 134, the cardioplegia solution and blood mixture in blood / cardioplegia solution supply line 135 is infused into heart 12 in either an antegrade or retrograde manner.

[0025] In some cases, the cardioplegia solution can be administered to the patient 10 according to three phases: (i) an induction dose, (ii) a maintenance dose, and (iii) a reperfusion or resuscitation dose. An induction dose (typically containing potassium) is administered to arrest the heart 12. A maintenance dose is then administered periodically (e.g., every 15 minutes) throughout the procedure to nourish the tissues of the heart 12. A reperfusion or resuscitation dose is administered near the end of the procedure to warm and restart the heart.

[0026] Cardiopulmonary bypass system 100 also includes one or more temperature control systems. In a first embodiment, temperature control system 130 is used to warm and cool the patient's blood in oxygenator 125 via a heat exchanger. Additionally, temperature control system 130 is used in conjunction with heat exchanger 134 to warm or cool the cardioplegia solution (and blood) delivered to patient 10 via blood / cardioplegia supply line 135. Typically, temperature control system 130 is used in a cooling mode during treatment (to reduce metabolic demand) and then used to warm the blood and / or cardioplegia solution as the surgical treatment nears its end. A perfusionist is tasked with monitoring and adjusting temperature control system 130 as needed during the surgical treatment.

[0027] The illustrated cardiopulmonary bypass system 100 also includes a blood monitoring system 140. The blood monitoring system 140 is used to monitor the extracorporeal blood of the patient 10 during the surgical procedure. Monitored parameters include, but are not limited to, pH, pCO2, pO2, K+, temperature, SO2, hematocrit, hemoglobin, base excess, bicarbonate, oxygen consumption, and oxygen delivery. A perfusionist is tasked with monitoring the blood monitoring system 140 during the surgical procedure. In some cases, the perfusionist will need to adjust other components or subsystems of the cardiopulmonary bypass system 100 in response to readings from the blood monitoring system 140.

[0028] The illustrated cardiopulmonary bypass system 100 also includes a perfusion data management system 150 and a regional oximetry system 160. These systems can also be used by a perfusionist to monitor the condition of the patient 10 and / or the condition of the cardiopulmonary bypass system 100 during the surgical procedure.

[0029] From the above description, it can be observed and understood that during a surgical procedure using cardiopulmonary bypass system 100, a perfusionist is tasked with a tremendous amount of very important and responsible work.

[0030] To centralize and automate some of the perfusionist's tasks related to cardioplegia solution delivery, the present disclosure describes a system of one or more syringe pumps for delivering cardioplegia solution that can be included as part of the cardiopulmonary bypass device system 100 or as a stand-alone system.

[0031] 2, cardiopulmonary bypass system 100 can include a system of one or more syringe pumps 170 for pumping one or more different types of cardioplegic agents into the oxygenated blood returning to heart 12 of patient 10 via blood / cardioplegia supply line 135. The system of syringe pumps 170 can be pole-mounted, configured on one or more racks, positioned on one or more carts, or a combination thereof.

[0032] The depicted syringe pump 170 system includes three syringe pumps 170a, 170b, 170c (or collectively 170a-c). However, in general, any number of syringe pumps 170 (e.g., 1, 2, 3, 4, 5, or more) corresponding to the number of cardioplegic agents to be used during a surgical procedure can be used.

[0033] In some embodiments, each syringe pump 170a, 170b, and 170c of the system of syringe pumps 170 can be individually in electrical signal communication with the programmed controller of heart-lung machine 110. Thus, in some such embodiments, the operation of each syringe pump 170a, 170b, and 170c can be individually controlled by the control system of heart-lung machine 110, and thereby in response to pre-programmed algorithms and / or user setup parameters and other user inputs. For example, each syringe pump 170a, 170b, and 170c can be individually controlled (by the control system of heart-lung machine 110) to initiate operation, to infuse its cardioplegic agent at a particular flow rate, to infuse a particular amount of cardioplegic agent, to operate for a particular amount of time, and / or to stop operation. Additionally, each syringe pump 170a, 170b, and 170c can be individually controlled in conjunction with other components of the heart-lung machine 110 (e.g., in conjunction with the cardioplegia pump 115) taking into account which phase (beginning, middle, or end) the surgical treatment is in. Additionally or alternatively, in some embodiments, the syringe pump 170 system is configured to be controlled / operate independently of the operation of the heart-lung machine 110.

[0034] In some embodiments, a dedicated user interface for the syringe pump 170 system is included through which a perfusionist can enter input to control the syringe pump 170 system. Alternatively or additionally, in some embodiments, the user interface of the heart-lung machine 110 can be used to receive user input to control the syringe pump 170 system.

[0035] The depicted syringe pump 170 system can be used in place of the cardioplegia solution pump 114 that delivers cardioplegia solution (including crystalloids) from the cardioplegia solution bag 132 as described above with reference to Figure 1. Use of the syringe pump 170 system allows the cardioplegia agent to be administered to the patient 10 without requiring the cardioplegia agent to be mixed / diluted with crystalloids. Thus, by using the syringe pump 170 system, the blood of the patient 10 will advantageously not be diluted as it would be if the conventional cardioplegia system of Figure 1 were used.

[0036] The blood / cardioplegia supply line 135 of the extracorporeal circuit 120 shown in FIG. 2 further includes a temperature sensor 180 (positioned after the heat exchanger 134), a bubble trap 182, and a pressure transducer 184. The temperature sensor 180 allows the perfusionist (and / or the control system of the heart-lung machine 110) to monitor and / or control the temperature of the oxygenated blood prior to the infusion of the cardioplegia agent from the syringe pumps 170a-c. The bubble trap 182 removes air bubbles that may be entrained in the blood / cardioplegia solution mixture before it reaches the heart 12. The pressure transducer 184 can be used by the perfusionist (and / or the control system of the heart-lung machine 110) to monitor the pressure of the blood / cardioplegia solution mixture in the blood / cardioplegia solution supply line 135. The pressure transducer 184 can facilitate the ability to control the flow rate of the cardioplegia solution and blood mixture to maintain a desired line pressure in the blood / cardioplegia solution for the desired cardioplegia solution dose delivery.

[0037] A system of multiple syringe pumps 170 advantageously allows individual cardioplegia agents to be delivered (infused) into blood / cardioplegia supply line 135 at different points with independent drug delivery rate control along blood / cardioplegia supply line 135 (rather than at a single point as with the conventional cardioplegia delivery system of FIG. 1 ). For example, in the depicted embodiment, syringe pumps 170b and 170c inject cardioplegia agent into blood / cardioplegia supply line 135 after heat exchanger 134 but before bubble trap 182, while syringe pump 170a injects the cardioplegia agent after bubble trap 182 (closer to the patient than syringe pumps 170b and 170c). The ability to inject cardioplegia agent at different points along blood / cardioplegia supply line 135 and inject cardioplegia agent closer to the patient is advantageous for reasons described herein.

[0038] FIG. 3 depicts a schematic diagram of a portion of the extracorporeal circuit 120 of FIG. 2, including an oxygenator 125, a cardioplegia pump 115, a blood / cardioplegia fluid supply line 135, a heat exchanger 134, a temperature probe 180, a bubble trap 182, a pressure transducer 184, and three syringe pumps 170a, 170b, and 170c.

[0039] Each syringe pump 170a-c of system 170 is an injection device used to controllably deliver a cardioplegic agent contained in an attached syringe at a precise flow rate. Each syringe pump 170a-c can have a housing portion configured to removably house a syringe containing the cardioplegic agent, a drive mechanism controllably operable to gradually drive the syringe plunger to inject the cardioplegic agent at a prescribed flow rate, and, optionally, a user interface for receiving input from a perfusionist.

[0040] A syringe containing a cardioplegic agent can be attached to each of the syringe pumps 170a-c before the surgical procedure begins. During attachment of the syringes in the syringe pumps 170a-c, the tips of the syringes are connected to tubing exiting the syringe pumps 170a-c via fluid safeties, such as Luer lock or compression fitting mechanisms. The tubing is in fluid communication with the blood / cardioplegia supply line 135, such as after (downstream from) the temperature probe 180.

[0041] The drive mechanism of each syringe pump 170a-c can be turned on / off and the flow rate from its syringes can be controlled based on control signals received from the heart-lung machine 110 and / or based on input from a perfusionist. For example, in some embodiments, the perfusionist can input the desired flow rates and / or agent-to-blood ratios for each of the cardioplegic agents.

[0042] In some embodiments, the perfusionist can input such defined flow rates and / or agent-to-blood ratios for each syringe pump 170 a-c during one or more time periods or phases occurring during a surgical procedure (e.g., an induction volume phase, a maintenance volume phase, and a reperfusion or resuscitation volume phase). In some embodiments, the perfusionist can program or control the flow rates individually or collectively. In some embodiments, the syringe pumps 170 a-c flow rates can be linked to automatically adjust based on the actual flow rate of the cardioplegia solution delivery pump 115. For example, in some embodiments, the perfusionist can set each of the syringe pumps 170 a-c to operate at a flow rate that is a percentage corresponding to the actual flow rate of the cardioplegia solution delivery pump 115. Alternatively, the perfusionist can set up the syringe pumps 170 a-c to operate at a flow rate that is a specific ratio to the actual flow rate of the cardioplegia solution delivery pump 115. Different percentages or ratios for each of the syringe pumps 170a-c can be pre-programmed by the perfusionist for each phase of the procedure (e.g., induction volume phase, maintenance volume phase, and reperfusion or resuscitation volume phase). In such cases, the control system of the heart-lung machine 110 and / or the syringe pump 170a-c system can automatically adjust to maintain the preset ratios established by the perfusionist.

[0043] Each syringe pump 170a-c of the system is fluidly coupled to the blood / cardioplegia supply line 135 at a separate point longitudinally spaced from one another. For example, FIG. 3 depicts syringe pumps 170b and 170c fluidly coupled to the blood / cardioplegia supply line 135 between a temperature sensor 180 and a bubble trap 182, and a third syringe pump 170a fluidly coupled to the blood / cardioplegia supply line 135 between a pressure transducer 184 and the patient 10. In this manner, cardioplegic agents (e.g., adenocaine, etc.) that may have a short medically active period can be advantageously infused (e.g., using syringe pump 170a) into the blood / cardioplegia supply line 135 closer to the patient 10. This increases the availability of such cardioplegic agents to the patient 10.

[0044] 4 schematically depicts an alternative drug delivery system 200 synchronized with an HLM. The drug delivery system 200 can be used in conjunction with a cardioplegia system configuration (e.g., the configurations of FIGS. 1, 2, and / or 3) or by itself without another cardioplegia system configuration.

[0045] Drug delivery system 200 includes syringe pump 270. While a single syringe pump 270 is depicted, it should be understood that two, three, or more than three syringe pumps 270 can be included in system 200 in some embodiments. Syringe pump 270 is configured to deliver one or more drug solutions as described above with reference to syringe pumps 170a-c. Syringe pump 270 can include any of the operational features as described above with reference to syringe pumps 170a-c. Additionally, syringe pump 270 is in bidirectional data communication with the control system of heart-lung machine 110 (FIG. 1). Thus, syringe pump 270 can be controlled by heart-lung machine control system 110 to operate in any of the manners as described above with reference to syringe pumps 170a-c.

[0046] Syringe pump 270 pumps one or more drug solutions into venous blood reservoir 123. In venous blood reservoir 123, the one or more drug solutions pumped from syringe pump 270 mix with the venous blood of patient 10. The mixture exits venous blood reservoir 123 and passes through arterial pump 124, oxygenator 125, and arterial filter 126 before being returned to patient 10.

[0047] A perfusionist user of drug delivery system 200 could enter into a user interface a target set point for the concentration (or dosage) of one or more drug solutions to be delivered from syringe pump 270. In some embodiments, the control system of heart-lung machine 110 (or syringe pump 270) can determine a flow rate for syringe pump 270 to operate to reach the targeted concentration of one or more drug solutions. Then, during operation, syringe pump 270 can be controlled to operate accordingly. The target set point can also be adjusted during operation of drug delivery system 200. The target set point input can be stored in memory of the control system of heart-lung machine 110 and / or the control system of syringe pump 270.

[0048] For some drugs to be delivered by syringe pump 270, the delivery rate can be linked to arterial blood flow, either directly or inversely. For other drugs, the delivery rate can be controlled independently of arterial blood flow. In either case, syringe pump 270 can be controlled to stop drug delivery when arterial blood flow stops (e.g., in response to an alarm condition, such as an alarm from the detection of air in arterial line 127). In some embodiments, syringe pumps 170a-c can be stopped directly in response to an alarm in heart-lung machine 110 (rather than in response to stopping the arterial pump). This is a safety feature that makes a control communication link to heart-lung machine 110 highly beneficial. In one example, when weaning a patient from extracorporeal membrane oxygenation (ECMO), the heparin delivered by syringe pump 270 can be increased to reduce the risk of blood clotting, and reduced / discontinued after the patient is weaned from ECMO.

[0049] Similar to the cardioplegia systems using syringe pumps 170a-c described above, when syringe pump 270 delivers a drug (e.g., a non-cardioplegic therapeutic agent) to the blood, the dose and timing parameters (e.g., start and stop times) are stored in memory of the control system of heart-lung machine 110 and / or the control system of syringe pump 270. Concentrations can also be stored. These data can be later retrieved / read as desired.

[0050] Drug delivery system 200 can be used to deliver a bolus dose of one or more medications from syringe pump 270. Data describing the delivery of such a bolus dose is stored in memory of the control system of heart-lung machine 110 and / or the control system of syringe pump 270.

[0051] In some embodiments, a user could set a low amount warning level for each drug / syringe in the syringe pump 270. The control system of the heart-lung machine 110 and / or the control system of the syringe pump 270 could keep track of the amount of drug being pumped from each syringe. An alert / alarm could be generated when the amount remaining in a syringe is at or below a low amount. In some embodiments, an expiration time could also be used as the basis for generating an alert / alarm. Thus, the amount of time remaining before the drug in the syringe runs out could be provided and / or used as the basis for generating an alert / alarm.

[0052] In some embodiments, the delivery of medication from syringe pump 270 may be at least in part based on mean arterial pressure (MAP) during treatment. For example, in some embodiments, the delivery of a vasodilator from syringe pump 270 may begin when the MAP exceeds a user-established set point and may stop when the MAP falls below another user-established set point. As another example, in some embodiments, the delivery of a vasopressor may begin when the MAP falls below a user-established set point and may stop when the MAP exceeds another user-established set point. As yet another example, in some embodiments, the delivery of medication from syringe pump 270 may be titrated based on continuous monitoring of MAP, such as the rate of change of MAP to a desired pressure set point.

[0053] Additional optional features The system can also track and display the time since the last cardioplegia dose, and in some embodiments, this timer automatically resets to zero when the next dose is not initiated.

[0054] During operation, the system can record / track the actual volume of blood and cardioplegic agent delivered for each phase of the cardioplegic scheme. For example, volume data for each cardioplegic agent administered can be displayed at the end of the treatment and / or during the treatment.

[0055] In some embodiments, a perfusionist can pre-program a cardioplegic scheme (e.g., including defined drug-to-blood ratios for each cardioplegic drug delivery / procedure phase) into the system. The system can then automatically (or semi-automatically) control the flow rate delivery of cardioplegic agents according to the program. Furthermore, such programs can be saved and reused.

[0056] In some embodiments, the system can selectively control / maintain cardioplegia line pressure using pressure sensor feedback as directed by the user.

[0057] The system can facilitate automatic simultaneous start / stop of the syringe pump with start / stop of the cardioplegic blood pump.

[0058] In some embodiments, the system can automatically calculate the cardioplegic drug flow rate for each delivery phase.

[0059] The system allows the perfusionist a convenient way to vary the cardioplegic drug-to-blood ratio on-the-fly during surgery.

[0060] In some embodiments, the local controller module is responsible for configuring and controlling each syringe pump using a communication link to each syringe pump. Syringe pump-based controls will not function and only the local display of the local controller module will be active.

[0061] In some such embodiments, the syringe pump and local control module are a stand-alone system (no need to interface with the heart-lung machine). In some embodiments, the syringe pump cannot operate independently of the heart-lung machine. For example, in some embodiments, a clinician cannot input configuration parameters or commands directly onto the syringe pump. Instead, all commands must come from the heart-lung machine. The only way the syringe pumps are operational is when they are connected to the heart-lung machine via the local controller. Furthermore, in some embodiments, the syringe pump mechanism can be incorporated into a housing to avoid the emergence of a stand-alone system that can operate independently of the heart-lung machine.

[0062] In some embodiments, all of the syringe pump mechanisms are mounted in a common housing, and each syringe pump can have a display, a stop button, and the required user interface to load and unload syringes.

[0063] In some embodiments, the local control module of the syringe pump system can display the fluid temperature when a temperature probe is linked to the local control module.

[0064] In some embodiments, syringe pump system setup can be completed using several different approaches. The first method is to access a cardioplegia setup screen from the heart-lung machine's central user interface monitor (e.g., with an on-screen keyboard). The user can create multiple setups, allowing for specific setups for each therapy and / or surgeon. These can be saved and reloaded as needed. This will then be downloaded to the local cardioplegia controller during setup. In some embodiments, most of the setup information will also be available via the local controller's display. For example, the user can edit everything except the drug name. In other cases, setup information for the syringe pump system can be electronically transferred from one heart-lung machine to another.

[0065] 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 controller will keep track of the amount of cardioplegic agent being pumped from each syringe. An alert / alarm will be generated when the amount remaining in the syringe is at or below the low volume alert level.

[0066] In some embodiments, the control system of the heart-lung machine 110 and / or the control system of the drug delivery system may include (or operate) a timer that may be used to issue a reminder to collect a blood sample for activated clotting time (ACT) specimen testing. In some embodiments, the control system of the heart-lung machine 110 and / or the control system of the cardioplegia delivery system may allow for ACT specimen test result entry via a user interface. In some such embodiments, the control system of the heart-lung machine 110 and / or the control system of the drug delivery system may suggest dose adjustments based on a user-established ACT target value and one or more patient parameters (e.g., patient weight, tolerable surface area, or calculated circulatory volume). The user-established ACT target value may be adjusted during therapy. All such set points, test results, and the like may be stored in memory of the control system of the heart-lung machine and / or the control system of the drug delivery system.

[0067] In some embodiments, at the end of a patient treatment using the systems described herein, the control device of the heart-lung machine 110 and / or the control system of the drug delivery system can provide the functionality to display all types of drugs delivered during the treatment and the doses / concentrations delivered. In some embodiments, the control system of the heart-lung machine 110 and / or the control system of the drug delivery system can be 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 treatment.

[0068] In some embodiments, each syringe pump includes a local user interface. In some cases, each local user interface may be identified with a particular syringe pump by having a colored light on the syringe pump that matches the background color of the local user interface. For example, some embodiments may use the same color scheme used by other pumps to identify the link between the local control and the syringe pump. In some embodiments, the local user interface displays one or more of the following types of information: drug name, drug flow rate, amount delivered, time duration of delivery, mean arterial pressure, soft keys for control functions such as start / stop and bolus delivery initiation, adjustment inputs (e.g., up / down arrows or knobs) for delivery ratio and other set point changes, notifications (e.g., low drug remaining, no drug remaining, etc.).

[0069] In some embodiments, the systems described herein can include one or more timers. For example, they can display the time since the last dose. In some such embodiments, notifications can be provided by the system based on the value of a timer, including, but not limited to, the time since the last dose of one or more cardioplegic agents.

[0070] Although the specification contains details of specific implementations, these should not be construed as limiting the scope of any inventions that may be claimed, but rather as descriptions of features specific to particular embodiments of a particular invention. Certain features described herein in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments in any suitable subcombination, or individually. Furthermore, although features may be described above as functioning in a certain combination, and even initially claimed as such, one or more features from a claimed combination may, in some cases, be deleted from that combination, and the claimed combination may be directed to subcombinations or variations of the subcombination.

[0071] Similarly, although acts are depicted in the figures in a particular order, this should not be understood as requiring that such acts be performed in the particular order or sequential order shown, or that all of the depicted acts be performed, to achieve desirable results. In some environments, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems may generally be integrated into a single software product or multiple packaged software products.

[0072] Specific embodiments of the present subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. In some implementations, multitasking and parallel processing may be advantageous. The inventions described in the original claims of this application are set forth below. [1] A cardiopulmonary bypass system, comprising: a heart-lung machine including an arterial blood pump and a cardioplegic blood pump; a first cardioplegia agent syringe pump configured to inject a first cardioplegia agent at a first location along the blood cardioplegia supply line; a second cardioplegia syringe pump configured to inject a second cardioplegia agent at a second location along the blood cardioplegia supply line, the first and second locations being longitudinally spaced from one another; a controller having a hardware processor and computer memory, the controller being in electrical signal communication with the cardioplegia blood pump and the first and second cardioplegia agent syringe pumps; The system, wherein the controller is configured to adjust the operating speed of the first and second cardioplegia agent syringe pumps based on an actual speed of the cardioplegia blood pump. [2] The system described in [1], wherein the control device is configured to receive user input that correlates the operating speed of the first and second cardioplegic agent syringe pumps with the actual speed of the cardioplegic blood pump. [3] The control device a first user input correlating the operating speed of the first cardioplegic agent syringe pump with the actual speed of the cardioplegic blood pump; and a second user input correlating the operating speed of the second cardioplegic agent syringe pump with the actual speed of the cardioplegic blood pump. [4] The system described in [3], wherein the control device is configured to adjust the operating speeds of the first and second cardioplegic agent syringe pumps based on the first and second user inputs, respectively. [5] The system described in [3], wherein the first and second user inputs are a ratio of flow rates. [6] The system described in [3], wherein the first and second user inputs are different from each other. [7] The system described in [1], wherein the control device is configured to stop the first and second cardioplegic agent syringe pumps in response to stopping the cardioplegic blood pump. [8] The control device a delivered amount of the first cardioplegic agent delivered from the first cardioplegic agent syringe pump; and The system according to [1], wherein the system is configured to track the amount of the second cardioplegic agent delivered from the second cardioplegic agent syringe pump. [9] further comprising a user interface display; the control device is configured to display the tracked and delivered amounts of the first and second cardioplegic agents; [8] The system of [8], wherein the control device is configured to issue an alert based on the tracked and delivered amount of the first cardioplegic agent or the second cardioplegic agent.

[10] further comprising a third cardioplegic agent syringe pump; The system of [1], wherein the control device is configured to adjust the operating speed of the third cardioplegic agent syringe pump based on the actual speed of the cardioplegic blood pump.

[11] The system described in [1], wherein the control device is configured to adjust the operating speed of the first and second cardioplegic agent syringe pumps based on the phase of operation of the system.

[12] The system described in [1], wherein the control device is configured to adjust the operating speed of the first and second cardioplegic agent syringe pumps based on at least three different phases of operation of the system.

[13] A method of operating a heart-lung machine system, comprising: receiving, by a controller of the heart-lung machine system, a user input indicating a defined correlation between a cardioplegia blood pump speed, (i) a first cardioplegia syringe pump speed, and (ii) a second cardioplegia syringe pump speed; adjusting, by a controller of the heart-lung machine system, the speed of the first cardioplegia agent syringe pump based on (i) the actual speed of the cardioplegia blood pump and (ii) a user input indicating a defined correlation between the speed of the cardioplegia blood pump and the speed of the first cardioplegia agent syringe pump; and adjusting, by a control device of the heart-lung machine system, the speed of the second cardioplegic agent syringe pump based on (i) the actual speed of the cardioplegic blood pump and (ii) a user input indicating a defined correlation between the speed of the cardioplegic blood pump and the speed of the second cardioplegic agent syringe pump.

[14] The method described in

[13] , wherein the defined correlation between the speed of the cardioplegic blood pump and the speed of the first cardioplegic agent syringe pump is different from the defined correlation between the speed of the cardioplegic blood pump and the speed of the second cardioplegic agent syringe pump.

[15] The method of

[13] , further comprising stopping the first and second cardioplegic agent syringe pumps by the heart-lung machine system in response to stopping the cardioplegic blood pump.

[16] The method of

[13] , further comprising receiving, by a control device of the heart-lung machine system, additional user input indicating additional defined correlations between the speed of the cardioplegia blood pump and (i) the speed of the first cardioplegia agent syringe pump and (ii) the speed of the second cardioplegia agent syringe pump for one or more additional phases of operating the heart-lung machine system.

[17] The method of

[13] , wherein the user input indicating the defined correlation between the speed of the cardioplegic blood pump and the speeds of the first and second cardioplegic agent syringe pumps is a ratio of flow rates.

[18] A cardiopulmonary bypass system, comprising: an arterial blood pump; a first syringe pump configured to deliver a first drug agent; a controller comprising a hardware processor and computer memory, the controller being in electrical signal communication with the arterial blood pump and the first syringe pump; The system, wherein the controller is configured to adjust the operating speed of the first syringe pump based on an actual speed of the arterial blood pump.

[19] Further comprising a second syringe pump configured to deliver a second drug agent;

[18] The system of

[18] , wherein the control device is configured to adjust the operating speed of the second syringe pump based on the actual speed of the arterial blood pump.

[20] The control device a first user input correlating the operating speed of the first syringe pump to the actual speed of the arterial blood pump; and a second user input correlating the operating speed of the second syringe pump to the actual speed of the arterial blood pump; the controller is configured to adjust the operating speeds of the first and second syringe pumps based on the first and second user inputs, respectively; the first and second user inputs being ratios of different flow rates;

[19] The system described in

[19] , wherein the control device is configured to stop the first and second syringe pumps in response to stopping the arterial blood pump.

Claims

1. 1. A cardiopulmonary bypass system comprising: a heart-lung machine including an arterial blood pump and a cardioplegic blood pump; a first cardioplegia syringe pump configured to inject a first cardioplegia agent at a first location along the blood cardioplegia supply line downstream of the heat exchanger; a second cardioplegia syringe pump configured to inject a second cardioplegia agent at a second location along the blood cardioplegia supply line downstream of the heat exchanger, the first and second locations being spaced apart longitudinally along the blood cardioplegia supply line from one another; a controller having a hardware processor and computer memory, the controller being in electrical signal communication with the cardioplegia blood pump and the first and second cardioplegia agent syringe pumps; the controller is configured to adjust the operating speeds of the first and second cardioplegia agent syringe pumps based on an actual speed of the cardioplegia blood pump; the controller is configured to receive user input correlating the operating speeds of the first and second cardioplegia agent syringe pumps with an actual speed of the cardioplegia blood pump; A system wherein the defined correlation between the speed of the cardioplegic blood pump and the speed of the first cardioplegic agent syringe pump is different from the defined correlation between the speed of the cardioplegic blood pump and the speed of the second cardioplegic agent syringe pump.

2. A cardiopulmonary bypass device system, comprising: a heart-lung machine including an arterial blood pump and a cardioplegic blood pump; a first cardioplegia syringe pump configured to inject a first cardioplegia agent at a first location along the blood cardioplegia supply line downstream of the heat exchanger; a second cardioplegia syringe pump configured to inject a second cardioplegia agent at a second location along the blood cardioplegia supply line downstream of the heat exchanger, the first and second locations being spaced apart longitudinally along the blood cardioplegia supply line from one another; a controller having a hardware processor and computer memory, the controller being in electrical signal communication with the cardioplegia blood pump and the first and second cardioplegia agent syringe pumps; the controller is configured to adjust the operating speeds of the first and second cardioplegia agent syringe pumps based on an actual speed of the cardioplegia blood pump; The control device a first user input correlating the operating speed of the first cardioplegic agent syringe pump with the actual speed of the cardioplegic blood pump; and a second user input correlating the operating speed of the second cardioplegia agent syringe pump with the actual speed of the cardioplegia blood pump; A system wherein the defined correlation between the speed of the cardioplegic blood pump and the speed of the first cardioplegic agent syringe pump is different from the defined correlation between the speed of the cardioplegic blood pump and the speed of the second cardioplegic agent syringe pump.

3. 3. The system of claim 2, wherein the controller is configured to adjust the operating speeds of the first and second cardioplegic agent syringe pumps based on the first and second user inputs, respectively.

4. The system of claim 2 , wherein the first and second user inputs are a ratio of flow rates.

5. The system of claim 1 or 2, wherein the controller is configured to stop the first and second cardioplegic agent syringe pumps in response to stopping the cardioplegic blood pump.

6. The control device a delivered amount of the first cardioplegic agent delivered from the first cardioplegic agent syringe pump; and 3. The system of claim 1, further configured to track a delivered amount of a second cardioplegic agent delivered from the second cardioplegic agent syringe pump.

7. further comprising a user interface display; the control device is configured to display the tracked delivered amounts of the first and second cardioplegic agents; 7. The system of claim 6, wherein the controller is configured to issue an alert based on the tracked delivered amount of the first cardioplegic agent or the second cardioplegic agent.

8. a third cardioplegic agent syringe pump; 3. The system of claim 1, wherein the controller is configured to adjust the operating speed of the third cardioplegic agent syringe pump based on an actual speed of the cardioplegic blood pump.

9. 3. The system of claim 1, wherein the controller is configured to adjust the operating speeds of the first and second cardioplegic agent syringe pumps based on a phase of operation of the system.

10. 3. The system of claim 1, wherein the controller is configured to adjust the operating speeds of the first and second cardioplegic agent syringe pumps based on at least three different phases of operation of the system.

11. 1. A method of operating a heart-lung machine system, comprising: a controller of the heart-lung machine system receiving user input indicating a defined correlation between a cardioplegia blood pump speed, (i) a first cardioplegia syringe pump speed, and (ii) a second cardioplegia syringe pump speed; a controller of the heart-lung machine system adjusting the speed of the first cardioplegic agent syringe pump based on (i) an actual speed of the cardioplegic blood pump and (ii) a user input indicating a defined correlation between the speed of the cardioplegic blood pump and the speed of the first cardioplegic agent syringe pump; a controller of the heart-lung machine system adjusting the speed of the second cardioplegia agent syringe pump based on (i) an actual speed of the cardioplegia blood pump and (ii) a user input indicating a defined correlation between the speed of the cardioplegia blood pump and the speed of the second cardioplegia agent syringe pump; A method wherein the defined correlation between the speed of the cardioplegic blood pump and the speed of the first cardioplegic agent syringe pump is different from the defined correlation between the speed of the cardioplegic blood pump and the speed of the second cardioplegic agent syringe pump.

12. 12. The method of claim 11, wherein the heart-lung machine system further comprises stopping the first and second cardioplegic agent syringe pumps in response to stopping the cardioplegic blood pump.

13. 12. The method of claim 11, further comprising the controller of the heart-lung machine system receiving additional user input indicating additional defined correlations between the speed of the cardioplegia blood pump, (i) the speed of the first cardioplegia agent syringe pump, and (ii) the speed of the second cardioplegia agent syringe pump for one or more additional phases of operating the heart-lung machine system.

14. 12. The method of claim 11, wherein the user input indicating a defined correlation between the speed of the cardioplegia blood pump and the speeds of the first and second cardioplegia agent syringe pumps is a ratio of flow rates.

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