Patent Description:
Perfusion entails encouraging physiological solutions such as blood through the vessels of the body or a portion of a body of a human or animal. Illustrative examples of situations that may employ perfusion include extracorporeal circulation during cardiopulmonary bypass surgery as well as other surgeries. In some instances, perfusion may be useful in providing extracorporeal circulation during various therapeutic treatments. Perfusion may be useful in maintaining the viability of body parts such as specific organs or limbs, either while the particular body part remains within the body, or while the body part is exterior to the body such as for transplantation or if the body part has been temporarily removed to provide access to other body structures. In some instances, perfusion may be used for a short period of time, typically defined as less than about six hours. In some cases, perfusion may be useful for extended periods of time that are greater than about six hours.

In some instances, blood perfusion systems include one or more pumps in an extracorporeal circuit that is interconnected with the vascular system of a patient. Cardiopulmonary bypass (CPB) surgery typically requires a perfusion system that allows for the temporary cessation of the heart by replacing the function of the heart and lungs. This creates a still operating field and allows for the surgical correction of vascular stenosis, valvular disorders, and congenital heart and great vessel defects. In perfusion systems used for cardiopulmonary bypass surgery, an extracorporeal blood circuit is established that includes at least one pump and an oxygenation device to replace the functions of the heart and lungs.

More specifically, in cardiopulmonary bypass procedures, oxygen-poor blood (i.e., venous blood) is gravity-drained or vacuum suctioned from a large vein entering the heart or other veins (e.g., femoral) in the body and is transferred through a venous line in the extracorporeal circuit. The venous blood is pumped to an oxygenator that provides for oxygen transfer to the blood. Oxygen may be introduced into the blood by transfer across a membrane or, less frequently, by bubbling oxygen through the blood. Concurrently, carbon dioxide is removed across the membrane. The oxygenated blood is then returned through an arterial line to the aorta, femoral, or other main artery.

The invention is defined by the features of independent claim <NUM>. Embodiments of the invention disclosed herein relate to an integrated perfusion system.

A method of operating a monitoring system for a heart lung machine is also disclosed, but does not fall under the claimed invention.

The disclosure pertains to a perfusion system that is easy to set-up, use and monitor during a bypass procedure. In some embodiments, the disclosure pertains to a perfusion system in which at least some of the disposable components used with the perfusion system are encoded with set-up and/or operational parameters. In some embodiments, the disclosure pertains to a perfusion system in which at least some of the disposable components used with the perfusion system are encoded with identifying information that can unlock additional functionality within the perfusion system.

In some embodiments, the disclosure pertains to a blood level sensor that can be used to monitor a blood level or volume within a blood reservoir. The blood level sensor may be utilized in an integrated perfusion system in which the disposable components are configured, as noted above, to communicate with the perfusion system. In some embodiments, the blood level sensor may be utilized with a perfusion system lacking communication with disposables.

<FIG> is a schematic illustration of an integrated perfusion system <NUM>. The integrated perfusion system <NUM> includes a heart lung machine (HLM) <NUM> and a disposable element <NUM>. The integrated perfusion system <NUM> also includes a data management system (DMS) <NUM>. While the HLM <NUM> and the DMS <NUM> are illustrated as distinct components, it will be appreciated that in some embodiments, at least some of the functionality of the DMS <NUM> may be integrated into the HLM <NUM>. In some embodiments, the HLM <NUM> and the DMS <NUM> are modular components or systems that can be connected together as desired, or used separately.

In some instances, at least some of the functionality described with respect to the DMS <NUM> may instead be incorporated into an inline blood monitor, or ILBM. An ILBM may be connected to the HLM <NUM> and may measure and/or monitor data directly via a sensor on a blood line. In some embodiments, an ILBM may receive information from the HLM <NUM> and/or the DMS <NUM>. An ILBM may accept manually inputted data, and may display data that is manually inputted or received from the HLM <NUM> or other devices.

It will be appreciated that while only a single disposable element <NUM> is shown for ease of illustration, in many embodiments a plurality of different disposable elements <NUM> may be utilized in combination with the HLM <NUM>. Each of the HLM <NUM>, the disposable element <NUM> and the DMS <NUM> will be described in greater detail subsequently. The HLM <NUM> includes a number of different components. It is to be understood that the particular components illustrated herein as being part of the HLM <NUM> is merely an example, as the HLM <NUM> may include other components or different numbers of components.

In the illustrated embodiment, the HLM <NUM> includes three pump modules <NUM>, but in embodiments of the invention it may include as few as two pump modules <NUM> or as many as six or seven pump modules <NUM>. In some embodiments, the pump modules <NUM> may be roller or peristaltic pumps. In some embodiments, one or more of the pump modules <NUM> may be centrifugal pumps. Each of the pump modules <NUM> may be used to provide fluid for delivery to or removal from the heart chambers and/or surgical field. In an illustrative but non-limiting example, one pump module <NUM> draws blood from the heart, another provides surgical suction and a third provides cardioplegia fluid (high potassium solution to arrest the heart). Additional pump modules <NUM> (not shown) may be added to provide additional fluid transfer.

Each pump module <NUM> includes a control unit <NUM>. In some embodiments, each control unit <NUM> may be configured to operate and monitor the operation of the particular pump module <NUM> to which it is attached or otherwise connected to. In some embodiments, each control unit <NUM> may include one or more input devices (not illustrated) such as switches, knobs, buttons, touch screens and the like so that the perfusionist may adjust the operation of the particular pump module <NUM>. Each pump module <NUM> may include an alphanumeric display that the control unit <NUM> can use to display, for example, the value of a setting, the value of a current operating parameter, confirmation that the pump module <NUM> is operating normally, and the like.

The HLM <NUM> includes a controller <NUM> that is in communication with the control units <NUM> and that is configured to operate the HLM <NUM>. In some embodiments, the controller <NUM> is configured to monitor one or more sensors that may be distributed on the HLM <NUM> and/or within the disposable element <NUM> to monitor operation of the HLM <NUM>. Examples of such sensors (not illustrated for ease of illustration) include but are not limited to flow meters, pressure sensors, temperature sensors, blood gas analyzers and the like.

While the control units <NUM> and the controller <NUM> are illustrated as distinct elements, in some embodiments it is contemplated that these elements may be combined in a single controller. In some embodiments, it is contemplated that the control units <NUM>, in combination, may be configured to operate the HLM <NUM>, thereby negating a need for the controller <NUM>.

The controller <NUM> communicates with an input device <NUM> and an output device <NUM>. The input device <NUM> is used by the perfusionist to enter information that is not otherwise entered into the control units <NUM>. The output device <NUM> may be used by the HLM <NUM> to display pertinent information to the perfusionist. In some embodiments, the input device <NUM> may be a key pad, a keyboard, a touch screen, and the like. In some embodiments, the output device <NUM> may be a monitor. In some embodiments, either of the input device <NUM> and/or the output device <NUM> may be a computer such as a personal computer, a laptop computer, a notebook computer or a tablet computer. In some cases, the input device <NUM> and the output device <NUM> may be manifested in a single computer.

In some embodiments, the DMS <NUM> may be considered as functioning as a flight recorder, recording data from a variety of sources, including the HLM <NUM> and various external sensors and monitoring devices. The DMS includes an RF sensor <NUM> and a processor <NUM>. The DMS <NUM> communicates with the HLM <NUM>. In some embodiments, as described herein, the DMS <NUM> also provides additional functionality that can be unlocked during use of the HLM <NUM> and/or the DMS <NUM>.

The DMS <NUM> is configured to receive and record data from the HLM <NUM>. In some embodiments, the DMS <NUM> may receive and record data from other sources as well, such as external devices. The DMS <NUM> may include an input device that permits a user to manually enter information. In some embodiments, as discussed herein, the DMS <NUM> may be configured to operate and display additional functionality. In some embodiments, the DMS <NUM> may be configured such that at least some of the disposable components <NUM> used with the integrated perfusion system <NUM> are encoded with identifying information that can unlock additional functionality within the DMS <NUM>. A variety of different additional functionality may be unlocked, depending on the identity of the disposable component.

The DMS <NUM> is configured to operate and display a metabolic algorithm. An illustrative but non-limiting example of a suitable metabolic algorithm is known as the Ranucci algorithm. The Ranucci algorithm provides continuous and real-time information regarding the patient's oxygen delivery (DO2) and their carbon dioxide production values (VCO2), as well as the adequacy of the DO2 with respect to the patient's metabolic requirements. The Ranucci algorithm is described, for example, in <CIT>; <CIT>; and <CIT>.

The RF sensor <NUM> may be configured to receive information from an active RFID tag placed on the disposable element <NUM>, including the aforementioned identity of the disposable component.

In some embodiments, the RF sensor <NUM> may be a hand held device that is used to scan a passive RFID tag on the disposable element <NUM>. According to other embodiments, the RF sensor <NUM> is replaced with any of a variety of known wireless communication receivers. The disposable element <NUM> includes an RFID tag <NUM>. According to various embodiments, the disposable element <NUM> includes either an active RFID tag or a passive RFID tag (or both) configured to communicate with the RF sensor <NUM>. In other embodiments, the RFID tag <NUM> is replaced with any of a variety of known wireless communication transmitters.

Passive RFID tags lack a power supply, and instead are powered by an induced current caused by an incoming radio-frequency scan. Because there is no onboard power supply, a passive RFID tag is smaller and less expensive. An active RFID tag includes an onboard power supply such as a battery. While this increases the size and expense of the RFID tag, an advantage is that the RFID tag can store more information and can transmit further. RFID tags, whether active or passive, may be selected to transmit at a variety of frequencies depending on need. Options include low frequency (about <NUM> to <NUM> kilohertz), high frequency (about <NUM> to <NUM> megahertz), ultra high frequency (about <NUM> to <NUM> megahertz) and microwave (about <NUM> gigahertz).

As noted above, the disposable element <NUM> may be considered as generically representing one, two or a plurality of different disposable elements that may be used in conjunction with the HLM <NUM>. Illustrative but non-limiting examples of disposable elements <NUM> include tubing sets, blood reservoirs, oxygenators, heat exchangers and arterial filters. In some embodiments, a tubing set includes a number of different tubes, potentially of different lengths and sizes, for providing fluid flow between components of the HLM <NUM> as well as providing fluid flow between the HLM <NUM> and a patient.

In some embodiments, the disposable element <NUM> may be a blood reservoir such as a venous blood reservoir, a vent blood reservoir, a cardiotomy or suction blood reservoir. In some embodiments, the disposable element <NUM> may be a blood reservoir that combines one or more of a venous blood reservoir, a vent reservoir and/or a suction reservoir in a single structure. In some embodiments, one or more of the aforementioned sensors are disposable elements that include an RFID tag <NUM> either to provide information identifying the sensor or even for transmitting sensed values to the controller <NUM>.

The RFID tag <NUM> is attached to the disposable element <NUM> in any appropriate manner. In some embodiments, the RFID tag <NUM> may be adhesively secured to the disposable element <NUM>. In some embodiments, the RFID tag <NUM> may be molded into the disposable element <NUM>. In some embodiments, the RFID tag <NUM> may be a stand alone card, similar in size and shape to a credit card, that may simply be packed with the disposable element <NUM> in such a way that it can be removed by the user and swiped by the RF sensor <NUM>. However the RFID tag <NUM> is attached, the RFID tag <NUM> is programmed with or otherwise configured to include a wide variety of information pertaining to the disposable element <NUM>.

In some embodiments, the RFID tag <NUM> includes data or identifying information for the disposable element <NUM>. Illustrative but non-limiting examples of identifying information include the name of the particular disposable element <NUM>, a reference code, a serial number, a lot number, an expiration date and the like. In some embodiments, this information may be communicated to the controller <NUM> and may, for example, be used by the controller <NUM> to confirm that the proper disposable elements <NUM> are being used for a particular setting, patient or the like. As an example, the controller <NUM> may recognize that a pediatric tubing set is being used in combination with an adult-sized blood reservoir or other component. As another example, the controller <NUM> may recognize that an expected component is missing. There are a variety of other potential mismatches in equipment that may be recognized by the controller <NUM> as a result of the information provided by the RFID tag <NUM> attached to each of the one or more disposable elements <NUM>.

In some embodiments, the RFID tag <NUM> may include descriptive or design information for the disposable element <NUM>. Illustrative but non-limiting examples of descriptive or design information include specific materials, a list of components, priming volume of a component or tubing circuit, tubing size, tubing length, minimum and maximum working pressures, minimum and maximum working volume, and the like. In some embodiments, this information may be communicated to the controller <NUM> and may be used by the controller <NUM> to at least partially configure and/or operate the HLM <NUM>. As an example, the controller <NUM> may use the sizing information provided from each of the disposable elements <NUM> to determine a working blood volume for the HLM <NUM>.

In some embodiments, the information obtained from the RFID tag <NUM> may also be provided to the perfusionist. In some embodiments, the output device <NUM> may be configured to provide alphanumeric or graphical representations of the obtained information. In some cases, the RFID tag <NUM> may include instructional information that may be displayed by the output device <NUM> in order to instruct the perfusionist in optimal setup and/or operation of a particular disposable element <NUM>. The RFID tab <NUM> may include warning information that can be transmitted from the RFID tag <NUM> and displayed on the output device <NUM>. In some embodiments, this warning information may supplement or even replace warning information that might otherwise be included as printed materials packaged with the disposable elements <NUM>.

In various embodiments, the output device <NUM> may be a computer such as a personal computer, a laptop computer, a notebook computer or a tablet computer. In some embodiments, the RFID tag <NUM> may include displayable information that, for example, suggests an optimal circuit design based upon the specific components being used, or perhaps updated use instructions. In some embodiments, information from the RFID tag <NUM> is displayed on the DMS <NUM>.

In some embodiments, the RFID tag <NUM> may include information that a manufacturer of the disposable element <NUM> wants to provide to the user. Examples of such information may include technical features of the disposable element <NUM> that have changed from a previous version or even a previous batch. Another example includes information that can be displayed by the output device <NUM> that require the user to acknowledge receipt of the information before the controller <NUM> proceeds with a particular procedure. In some cases, the RFID tag <NUM> may receive error messages from the DMS <NUM> and/or the controller <NUM>, and the RFID tag <NUM> may then be returned to the manufacturer, thereby providing the manufacturer with feedback regarding the performance of the disposable element <NUM> as well as other components.

In some embodiments, the RFID tag <NUM> may include information that can be used by an inventory tracking system. In some embodiments, the inventory tracking system may be in communication with the perfusion system <NUM>. In some embodiments, the inventory tracking system may independently and directly receive information from the RFID tag <NUM> without communicating through the perfusion system <NUM>.

<FIG> is a flow diagram illustrating a method that may be carried out using the perfusion system <NUM> of <FIG>. A disposable element <NUM> having an RFID tag <NUM> may be attached to the HLM <NUM>, as generally shown at block <NUM>. At block <NUM>, the RFID tag <NUM> is read. As noted above, the RFID tag <NUM> may be an active RFID tag or a passive RFID tag. In some embodiments, the RFID tag <NUM> may be read before the disposable element <NUM> is attached to the HLM <NUM>. In some embodiments, the RFID tag <NUM> may be read after attachment. At block <NUM>, the HLM <NUM> is configured based at least in part upon information that was read from the RFID tag <NUM> at block <NUM>. In some embodiments, the controller <NUM> automatically configures the HLM <NUM> in response to this information. In some embodiments, at least some of the information read from the RFID tag <NUM> may be captured by the DMS <NUM>.

<FIG> is a flow diagram illustrating a method that may be carried out using the perfusion system <NUM> of <FIG>. A disposable element <NUM> having an RFID tag <NUM> may be attached to the HLM <NUM>, as generally shown at block <NUM>. At block <NUM>, the RFID tag <NUM> is read. The RFID tag <NUM> may be read either before or after the disposable element <NUM> is attached to the HLM <NUM>. At block <NUM>, the HLM <NUM> is configured based at least in part upon information that was read from the RFID tag <NUM> at block <NUM>. In some embodiments, the controller <NUM> automatically configures the HLM <NUM> in response to this information. At least some of the information read from the RFID tag <NUM> may be displayed on the output device <NUM>, as seen at block <NUM>, or on the DMS <NUM>.

<FIG> is a schematic illustration of a heart lung machine pack <NUM> that may be utilized with the perfusion system <NUM> of <FIG>. In some embodiments, the heart lung machine pack <NUM> may include all of the disposable elements <NUM> that will be used together for a particular patient and may be customized for the particular patient. In some embodiments, the heart lung machine pack <NUM> may include a housing <NUM> that, once filled, can be sealed up to keep the contents clean and sterile.

In the illustrated embodiment, the heart lung machine pack <NUM> includes a tubing set <NUM> and a disposable component <NUM>. The tubing set <NUM> may include a plurality of different tubes. The disposable component <NUM> may be any of the disposable components discussed above with respect to the disposable element <NUM>. In some embodiments, the heart lung machine pack <NUM> will include a plurality of different disposable components <NUM>. The tubing set <NUM> includes a first RFID tag <NUM> while the disposable component <NUM> includes a second RFID tag <NUM>. As discussed above, each of the first RFID tag <NUM> and the second RFID tag <NUM> may be either active or passive RFID tags and may include readable information pertaining to the component to which they are attached. In some instances, the housing <NUM> may include a third RFID tag <NUM> that, for example, identifies the contents of the heart lung machine pack <NUM>. In some embodiments, the first RFID tag <NUM> and the second RFID tag <NUM> may not be included, as the third RFID tag <NUM> may be encoded with all of the information for the tubing set <NUM> and the disposable component <NUM>.

<FIG> is a schematic illustration of a perfusion system <NUM>. The perfusion system <NUM> includes an HLM <NUM> that in some examples may be similar in structure and operation to the HLM <NUM> discussed with respect to <FIG>. The perfusion system <NUM> also includes a blood reservoir <NUM>, a blood level sensor <NUM> and a controller <NUM>. The blood reservoir <NUM> may be a venous blood reservoir, a vent blood reservoir, a cardiotomy or suction blood reservoir. In some embodiments, the blood reservoir <NUM> may be a blood reservoir that combines one or more of a venous blood reservoir, a vent reservoir and/or a suction reservoir in a single structure.

The blood level sensor <NUM> may be configured to continuously monitor a variable blood level within the blood reservoir <NUM>. The blood level sensor may be chosen from a variety of different sensing technologies. In some embodiments, as will be discussed subsequently with respect to <FIG>, the blood level sensor <NUM> may be an ultrasonic sensor in which ultrasound is used to detect the blood level within the blood reservoir <NUM>. In some embodiments, the blood level sensor <NUM> may be an optical sensor in which a laser beam or light from an infrared light source is reflected by the liquid-air interface and the reflected light beam is detected by the blood level sensor <NUM>. According to exemplary embodiments, the blood level sensor <NUM> is an optical distance sensor of the type commercially sold by Leuze electronic GmbH located in Owen/Teck, Germany (e.g., ODSL8, ODSL <NUM>, or ODS <NUM>). In some embodiments, the blood level sensor <NUM> may be a load cell or scale that is configured to measure a mass of the blood reservoir <NUM> and thereby determine the volume of blood therein.

In some examples, the blood level sensor <NUM> may be a capacitive sensor (better illustrated in subsequent Figures) that outputs an electrical signal that is proportional to or otherwise related to a blood level within the blood reservoir <NUM>. The electrical signal may be communicated in either a wired or wireless fashion to the controller <NUM>. While the controller <NUM> is shown as a distinct element, in some embodiments the controller <NUM> is manifested as part of a controller (similar to the controller <NUM>) operating the HLM <NUM>.

In some examples, the blood level sensor <NUM> may be modeled after capacitive sensors (e.g., CLC or CLW series) available commercially from Sensortechnics GmbH located in Puchheim, Germany, which are configured to provide contact-free measurement of continuous liquid level. The sensor available from Sensortechnics may be disposed on an outer surface of a container and provides an electrical signal representative of the liquid level within the container. In some instances, the Sensortechnics sensor may be spaced as much as about five millimeters from the liquid within the sensor, with no more than about twenty percent air gap between the sensor and the liquid. According to various embodiments, the capacitive sensor <NUM> is molded inside the blood reservoir <NUM>, such that only the connector is accessible outside the reservoir. In these embodiments, the sensor <NUM> is protected by the plastic material of the blood reservoir.

In some examples, the sensor may undergo an initial configuration to adapt the sensor to the particulars of the container itself as well as the liquid within the container. In some embodiments, the blood level sensor <NUM> has a five pin electrical connection, including a voltage source, an analog signal out, a digital signal out, a teach-in pin and a ground. In some embodiments, the level sensor <NUM> is a capacitive sensor such as the Balluff SmartLevel sensor commercially sold by Balluff GmbH located in Neuhausen, Germany.

The controller <NUM> may receive an electrical signal that is proportional to or at least related to a blood level within the blood reservoir <NUM>. The controller <NUM> may calculate a blood volume based on this electrical signal as well as a known shape or geometry of the blood reservoir <NUM>. In some embodiments, the blood reservoir <NUM> may include an RFID tag (not illustrated) that provides the controller <NUM> with information pertaining to the known geometry of the blood reservoir <NUM>.

If the blood reservoir <NUM> is a hard shell blood reservoir, the known geometry of the blood reservoir <NUM> may include the cross-sectional area of the blood reservoir <NUM>, or a width and depth of the blood reservoir <NUM> as well as details on how this cross-sectional area varies relative to height within the blood reservoir <NUM>. If the blood reservoir <NUM> is a soft shell reservoir, the known geometry may be based at least in part upon a known lateral expansion rate of the soft shell reservoir relative to the blood level within the blood reservoir <NUM>.

As can be seen in <FIG>, the blood level sensor <NUM> includes a first elongate electrode <NUM> and a second elongate electrode <NUM>. The first elongate electrode <NUM> and the second elongate electrode <NUM> are disposed along a flexible substrate <NUM>. In some embodiments, the flexible substrate <NUM> may include an adhesive layer that can be used to secure the blood level sensor <NUM> to the blood reservoir <NUM>. A connector socket <NUM> is secured to the flexible substrate <NUM> and is electrically connected to the first elongate electrode <NUM> and the second elongate electrode <NUM> in order to permit an electrical connection between the first and second electrodes <NUM>, <NUM> and an electrical cable (not illustrated in this Figure). In some embodiments, rather than an elongate sensor, the blood level sensor <NUM> may include two or more distinct SMARTLEVEL™ capacitive sensors such as those available commercially from Balluff. These sensors may provide a binary, yes/no signal. By locating several of these sensors at differing levels proximate the blood reservoir <NUM>, the blood level within the blood reservoir <NUM> may be determined.

In some embodiments, the blood level sensor <NUM> may be attached to or otherwise integrated into a label <NUM> as seen in <FIG>. The label <NUM> may include various indicia <NUM> such as use instructions, volume indicators and the like. In some embodiments, the label <NUM> may include an adhesive side for attachment to an outer surface of the blood reservoir <NUM>. In some embodiments, the label <NUM> is oriented on the blood reservoir such that a lower portion of the blood level sensor <NUM> is aligned at or near a bottom of the blood reservoir <NUM>.

In some examples, the blood level sensor may be an ultrasonic blood level sensor, as illustrated in <FIG> is an illustration of a blood reservoir <NUM> that contains a volume of blood. The volume of blood defines an interface <NUM> between the volume of blood and the air or other fluid within the blood reservoir <NUM>. In some embodiments, an ultrasonic transducer <NUM> that is located at or near a lower surface of the blood reservoir <NUM> can be used to locate the interface <NUM> by transmitting ultrasonic waves <NUM> towards the interface <NUM>. The reflectance of the ultrasonic waves <NUM> depend at least in part upon the fluid they are passing through. Thus, by measuring the reflectance, the ultrasonic transducer <NUM> can determine how far away the interface <NUM> is and thereby determine the fluid level. Based on the fluid level and the geometric configuration of the blood reservoir <NUM>, a controller may determine the blood volume within the blood reservoir <NUM>. In some examples, a cable <NUM> transmits a signal from the ultrasonic transducer <NUM> to the controller. In some embodiments, the information is transmitted wirelessly, such as via an RFID tag attached to the ultrasonic transducer.

<FIG> is similar to <FIG>, but shows a blood reservoir <NUM> having a blood volume defining an interface <NUM>. In this embodiment, an ultrasonic transducer <NUM> is located at or near a top of the blood reservoir <NUM> and transmits ultrasonic waves <NUM> downward towards the interface <NUM>. In some embodiments, a cable <NUM> transmits a signal from the ultrasonic transducer <NUM> while in other embodiments this is done wirelessly, such as with an RFID tag attached to the ultrasonic transducer <NUM>. A primary difference between the embodiments shown in <FIG> is that in <FIG>, the interface <NUM> is detected from below, or through the blood, while in <FIG> the interface <NUM> is detected from above, or through the air.

In some examples, the blood level sensor may be an infrared (IR) light blood level sensor. In some embodiments, an infrared light source positioned at or near a lower surface of the blood reservoir <NUM> may be used to locate a fluid/air interface within the blood reservoir <NUM> by transmitting infrared light towards the interface. Alternatively, the infrared light blood level sensor may be located above the interface. In some embodiments, the infrared light blood level sensor may be located a short distance away from the blood reservoir <NUM> and thus can be attached to a mechanical holder for the blood level reservoir <NUM>.

In some instances, the infrared light is reflected back towards the infrared light blood level sensor. By measuring the reflectance, the location of the interface may be determined. In some embodiments, the infrared light travels through the blood to an infrared light sensor located opposite the infrared light blood level sensor. By detecting changes in the received light, the interface location may be determined. By combining the interface location with known geometric parameters of the blood reservoir <NUM>, the controller <NUM> can determine the blood volume within the blood reservoir <NUM>. In some embodiments, this information is transmitted wirelessly to the controller <NUM>, such as via an RFID tag attached to the infrared light blood level sensor.

<FIG> is an illustration of the blood level sensor <NUM> attached to the blood reservoir <NUM>. An electrical cable <NUM> provides an electrical connection between the blood level sensor <NUM> and the controller <NUM>. The electrical cable <NUM> includes a plug <NUM> that is configured to connect to the electrical connector <NUM>. In some embodiments, the plug <NUM> includes circuitry that converts a detected capacitance into a voltage signal that the controller <NUM> can use to calculate the blood volume. In some embodiments, the plug <NUM> further includes circuitry to calculate the blood volume.

As noted above, the blood reservoir <NUM> may be either a hard shell reservoir or a soft shell reservoir. <FIG> illustrates a hard shell reservoir <NUM> bearing the blood level sensor <NUM> while <FIG> illustrates a soft shell reservoir <NUM> including the blood level sensor <NUM>. In either case, the reservoir may be constructed to include the blood level sensor <NUM>. In some embodiments, the blood level sensor <NUM> may be adhesively secured to an existing blood reservoir.

<FIG> is a flow diagram illustrating a method that may be carried out using the perfusion system <NUM> of <FIG>. A capacitance between first and second electrodes may be detected, as referenced at block <NUM>. In some embodiments, as discussed above, the capacitance may be converted into an electrical signal representing the blood level by circuitry within the plug <NUM>. In embodiments using the CLC series Sensortechnics sensor, for example, the sensor will output a voltage between <NUM> and <NUM> volts. Assuming the sensor pad is appropriately located on the reservoir, this voltage indicates a level or height of the liquid in the reservoir. At block <NUM>, the controller <NUM> may calculate a blood volume that is based upon the detected capacitance and a known dimensions or geometry of the blood reservoir <NUM>. In some embodiments, the controller <NUM> (or other circuitry within the HLM <NUM>) may provide the circuitry in the plug <NUM> with sufficient information (e.g., dimensions or geometry) regarding the blood reservoir <NUM> to permit the circuitry to perform the blood volume calculation. In some embodiments, the calculated blood volume is communicated to the HLM <NUM> so that it may adjust an operating parameter of the HLM <NUM>. In various exemplary embodiments, the HLM <NUM> may alter a pump speed to either increase or decrease blood flow into or out of the blood reservoir <NUM>. It may be important, for example, to prevent the blood level in the reservoir <NUM> from moving below a certain minimum level or volume. Accordingly, in various embodiments, the HLM <NUM> will compare the blood level or volume to this minimum level and adjust pump speed appropriately.

According to other examples, the HLM <NUM> may use the blood volume information for a variety of applications, including for example auto-regulation of pump occlusion, auto-loading of pump segments, conducting automatic occlusivity testing, performing automatic priming, automatic recirculating and debubbling, conducting automatic pressure tests, or performing automatic system emptying.

In some embodiments, and as noted above, the perfusion system <NUM> is configured such that at least some of the disposable components used with the perfusion system <NUM> are encoded with identifying information that can unlock additional functionality within the perfusion system. A variety of different additional functionality may be unlocked, depending on the identity of the disposable component.

In some embodiments, for example, if the disposable component is or otherwise includes a tubing set (such as the tubing set <NUM> shown in <FIG>), the tubing set may include an RFID tag (such as the <NUM>st RFID <NUM> shown in <FIG>) that is programmed or otherwise includes information that can be used by the perfusion system <NUM> to determine the priming volume of a blood circulation system. The blood circulation system may include only items included in the tubing set, or the blood circulation system may include additional items.

The presence of the tubing set may enable the DMS <NUM> to operate and display a priming volume simulator. In some embodiments, for example if a different tubing set is used, or perhaps a tubing set from a different manufacturer, the priming volume simulator may be disabled or otherwise not permitted to function. Hence, the presence of the particular tubing set (or other disposable component) may unlock the additional functionality of a priming volume simulator.

The DMS <NUM> is configured to operate and display an algorithm that monitors and/or provides data related to a patient's metabolism. In some embodiments, the algorithm may be unlocked by the DMS <NUM>, depending on the identity of the disposable component <NUM>. While a variety of different algorithms are known and may be unlocked by the DMS <NUM>, an illustrative but non-limiting example of an algorithm that can be programmed into the perfusion system <NUM> and that may be unlocked if appropriate disposable components <NUM> are used includes a priming volume simulator. Another example is a metabolic algorithm is known as the Ranucci algorithm, referenced above.

In understanding and describing the Ranucci algorithm, certain definitions are useful.

The following equations are useful in the Ranucci algorithm. <MAT><MAT><MAT><MAT><MAT><MAT><MAT><MAT> <MAT>.

The oxygen consumption (VO2) is the sum of the metabolic needs of each specific organ and thus represents the metabolic needs of the whole organism. Under basal conditions (at rest), it is about <NUM>-<NUM>/min/kg, i.e. about <NUM>/min for a subject weighting <NUM> kgs. Applying equations (<NUM>) and (<NUM>), the oxygen delivery (DO2) may be calculated, and is about <NUM>/min. Therefore, a considerable functional reserve exists, since the DO2 is about <NUM> times greater than the VO2. The VO2 may increase depending on the metabolic needs (basically under physical exercise, but even in pathologic conditions like septic shock). A top level endurance athlete may reach a maximal VO2 of about <NUM>/min.

Of course, to meet these increasing oxygen demands, the DO2 must increase as well: it can reach, in an athlete during exercise, the value of <NUM>/min (Qc: <NUM>/min with an unchanged arterial oxygen content of <NUM>/dL). As a consequence, the O2 ER may increase up to <NUM>%.

<FIG> is a diagram showing the relationship between DO2 and VO2 in an athlete during physical exercise. If the athlete (that, for example, is running a marathon) falls into the dark triangular zone (where the DO2 is unable to support the VO2), the athlete is forced to use other metabolic mechanisms in order to develop mechanical energy. In particular, the athlete will undergo anaerobic lactacid metabolism, which develops energy but at the expenses of lactic acid formation, local and systemic acidosis, and finally exercise stops usually within <NUM> minutes. In other words, the VO2 is physiologically dependent on the DO2.

In the medical field, of course, the situation is different. The DO2 may pathologically decrease in case of: decreased arterial oxygen content due to anemia; decreased arterial oxygen content due to hypoxia; and decreased cardiac output. However, due to the existence of the above-mentioned physiological reserve, the VO2 may be maintained even for a DO2 decrease down to about <NUM>/min (DO2i <NUM>/min/m<NUM>), due to the increased O2 ER.

<FIG> is a diagram showing the relationship between DO2 and VO2 in the range observed during medical conditions (i.e. cardiac operation). Below a DO2 of <NUM>/min, VO2 starts decreasing. The patient meets, exactly as the athlete, a lactic acidosis, with lactate (LAC) production. In other words, the patient experiences a shock. The DO2 level below which the VO2 starts decreasing and becomes pathologically dependent on the DO2 is called the critical DO2 (DO2crit). Maintaining the DO2 above this threshold is very important in many pathological conditions, to avoid an acidosis-shock status. The DO2crit is higher during a septic shock.

Since <NUM>, in a paper published in Perfusion, Ranucci and coworkers demonstrated that in a series of <NUM> consecutive patients that underwent myocardial revascularization with CPB, the presence of a severe hemodilution was an independent risk factor for a postoperative acute renal failure (ARF). In particular, the cut-off value was identified at an HCT<<NUM>%.

Subsequently, other authors have demonstrated that the lowest HCT during CPB was an independent risk factor for many "adverse outcomes" in cardiac surgery. Stafford-Smith and coworkers, in <NUM> (Anesth Analg), confirmed the relationship between hemodilution and ARF.

More recently, the lowest hematocrit on CPB has been recognized as an independent risk factor for postoperative low cardiac output and hospital mortality by <NPL>), and for an impressive series of postoperative adverse events by <NPL>). The relationship between hemodilution and ARF has been subsequently confirmed by <NPL>), <NPL>) and <NPL>). The critical HCT value below which the ARF risk significantly increases is located between <NUM>% and <NUM>%.

Almost all the authors ascribe this relationship to an insufficient oxygen supply (DO2) to the various organs. The kidney, in particular, due to its physiologic condition of hypoxic perfusion, seems to be at high risk.

Surprisingly, all the studies demonstrating a relationship between HCT and ARF or other organ damages failed to consider that the HCT is only one of the two determinants of the DO2 during CPB: the other is the pump flow (Qp). This would not influence the DO2 if the Qp was a constant, but this is not the case. In all the studies, the pump flow (Qp) varied from a Qpi of <NUM>/min/m<NUM> to a Qpi of <NUM>/min/ m<NUM>, and the variation was dependent on the perfusion pressure. An HCT of <NUM>% results in a DO2i of <NUM>/min/m<NUM> if the Qpi is <NUM>/min/ m<NUM>, and of <NUM>/min/ m<NUM> if the Qpi is <NUM>/min/m<NUM>.

In a scientific paper in The Annals of Thoracic Surgery, Ranucci and coworkers actually demonstrated that the DO2i, rather than the HCT, is the best predictor of ARF. Moreover, in presence of perioperative blood transfusions, the DO2i remains the only determinant of ARF. The DO2crit identified in this paper is <NUM>/min/ m<NUM>, very close to the one previously defined as the DO2i below which the VO2 becomes pathologically dependent on the DO2. In other words, maintaining the DO2i above this threshold allows a decrease in the hypoxic organ dysfunction or the elimination of the hypoxic organ dysfunction; in presence of a low HCT, an adequate increase of the Qp may minimize the deleterious effects of hypoxemia. As a consequence, a continuous monitoring of the DO2 is of paramount importance in order to limit the postoperative complications, namely the renal ones.

Measuring a low HCT has poor clinical value, since the only possible (and arguable) countermeasure is a blood transfusion. On the other hand, the DO2 may be modulated by increasing the pump flow.

The level of DO2crit, below which the LAC production begins, is identified by the concept of "anaerobic threshold" (AT). In athletes, it is the level of expressed mechanical power at which the LAC production begins; in a patient, it is the level of DO2crit, below which the LAC production begins.

It has been demonstrated that the LAC value during CPB is predictive for postoperative complications. The problem is that the LAC value is not available on-line, and only some devices (blood gas analyzers) provide it. It is however possible to make an "indirect" assessment of the AT. As a matter of fact, under steady conditions, the VO2/VCO2 ratio is a constant, while during anaerobic lactacid metabolism the VCO2 increases more than the VO2. This happens because the lactic acid undergoes the following transformation: H LAC+NaHCO<NUM>=LAC Na+H<NUM>CO<NUM> and the H<NUM>CO<NUM> is split into H<NUM>O and CO<NUM>, with a further CO<NUM> production.

<FIG> is a diagram showing the relationship between VO2 and VCO2. The relationship between VCO2 and LAC production has been demonstrated in <NUM> consecutive patients under CPB, in an experimental trial performed by the inventor himself. In <FIG>, the graphical relationship between VCO2 and LAC production is reported. From this relationship, it appears that a VCOi value of <NUM>/min/m<NUM> is a sensitive predictor of lactic acidosis.

Under normal resting conditions, oxygen delivery matches the overall metabolic demands of the organs and the oxygen consumption (VO2) is about <NUM>% of the oxygen delivery (DO2), and energy is produced basically through the aerobic mechanism (oxidative phosphorylation). When the DO2 starts decreasing (due to a decreased cardiac output, extreme hemodilution, or both), the VO2 is maintained until a "critical level" is reached. Below this critical point the oxygen consumption starts decreasing, becoming dependent on the oxygen delivery, and the failing aerobic energy production is progressively replaced by anaerobic adenosine triphosphate production (pyruvate conversion to lactate).

As a result, blood lactate concentration starts rising, and numerous studies have established the use of lactates as a marker of global tissue hypoxia in circulatory shock. Under these circumstances, the anaerobic metabolism results in an excess of proton production and tissue acidosis; buffering of the protons by bicarbonate ions results, in turn, in an anaerobic carbon dioxide production (VCO2). Therefore, below the critical DO2, there is a linear decrease of both VO2 and VCO2, but due to the anaerobic CO2 production, the respiratory quotient (VCO2/VO2) RQ increases. When the critical DO2 is reached due to a decrease in cardiac output (cardiogenic shock), the above relationship becomes more complex.

Due to the reduced pulmonary flow and to ventilation-perfusion mismatch, the ability of the lung to eliminate carbon dioxide is impaired, and carbon dioxide elimination and end-tidal carbon dioxide tension are decreased. Consequently, carbon dioxide starts accumulating in the venous compartment, and the venoarterial carbon dioxide gradient is increased. In other terms, the VCO2 (intended as carbon dioxide production by the tissues) becomes progressively higher than carbon dioxide elimination.

Under CPB conditions, the above pattern changes again. The artificial lung is much more efficient than the natural lung in terms of carbon dioxide clearance, and is maintained even for a very low pump flow. Not by chance, under specific circumstances like deep hypothermia and according to the pH strategy, it is clinically needed to add carbon dioxide to the gas flow in order to avoid dramatic and dangerous patterns of hypocapnia. In this setting, the VCO2 is strictly correlated to the carbon dioxide elimination.

Therefore, while in a normal setting the venous carbon dioxide tension (PvCO2) is inverse to the carbon dioxide elimination, during CPB the two parameters are positively correlated. Subsequently, Ranucci and coworkers found that the best predictor of hyperlactatemia during CPB was the DO2/VCO2 ratio, with a cut off value around <NUM>, and the VCO2, with a cut off value at <NUM>/min/m2.

In some embodiments, it is believed that low values of DO2 during CPB may create an ischemic environment to the kidney. Extremely low values of DO2 may trigger anaerobic metabolism with lactate production. This may be detected using CO2-derived parameters.

In some embodiments, therefore, the integrated perfusion system <NUM> may include one or more of a pump flow reading device and a hematocrit value reading device. The integrated perfusion <NUM> system includes an input device <NUM> and a controller <NUM> that is programmed or otherwise configured to compute the oxygen delivery (DO2i) value on the basis of the measured pump flow (Qp), the measured hematocrit (HCT), the preset value of arterial oxygen saturation (Sat(a)), and the preset value of arterial oxygen tension (PaO2) and a display.

In some embodiments, the perfusion system <NUM> also includes a CO2 reading device for continuously detecting exhaled CO2 (eCO2) at the oxygenator gas escape of the HLM. The input device <NUM> allows the operator to insert a gas flow value (Ve) and the controller <NUM> computes the CO2 production (VCO2i) on the basis of the preset gas flow (Ve) value and the detected exhaled CO2 (eCO2), and the output device <NUM> shows the calculated value of CO2 production (VCO2i).

In some embodiments, the controller <NUM> is programmed or otherwise configured to compare the above mentioned oxygen delivery (DO2i) value with a threshold value of oxygen delivery (DO2icrit) and to trigger an alarm when the oxygen delivery (DO2i) value falls below the threshold value of oxygen delivery (DO2icrit). In one embodiment, the threshold value of oxygen delivery (DO2icrit) is preset by the operator at a value of about <NUM>/min/m<NUM>.

In some embodiments, the perfusion system <NUM> further includes a temperature detecting device configured to continuously measure a body temperature (T) of the patient and to send the temperature values to the controller <NUM>, to be subsequently displayed by the output device <NUM>. The controller <NUM> may be programmed or otherwise configured to calculate, based on the temperature (T) of the patient, an oxygen delivery threshold. In some embodiments, the controller <NUM> is programmed or otherwise configured to calculate the hemoglobin (Hb) value from the detected hematocrit (HCT) value.

<FIG> shows a patient <NUM> laying on a surgical table <NUM>. An embodiment of a HLM <NUM>, is connected to the patient <NUM>. A HLM <NUM> includes a venous extracorporeal circuit, collecting blood from the venous system of the patient. A roller or centrifugal mechanical pump <NUM> pumps the venous blood from a venous extracorporeal circuit towards an oxygenator <NUM>, whose role is removing CO2 from the venous blood and supplying oxygen (O2). The blood oxygenated by the oxygenator <NUM>, is sent, again by the same roller or centrifugal pump <NUM>, to an arterial extracorporeal circuit connected to the arterial system of the patient, therefore creating a total bypass of the heart and lungs of the patient.

The monitoring system <NUM>, is operatively connected to the heart-lung machine <NUM> and may include a processor that is able to perform calculations, as subsequently explained, and a monitor screen or display <NUM> that provides an interface with the operator. Using a knob <NUM> (seen in <FIG> and <FIG>), an operator may manually input data.

Examples of data that may be manually inputted include, but are not limited to, the height and weight of the patient and the arterial oxygen saturation (Sat(a)). While this value is usually <NUM> percent, in some situations such as oxygenator malfunction, the value may decrease. In some embodiments, the arterial oxygen saturation value may be continuously or discretely (every twenty minutes or so) monitored by an external device that may be connected to the DMS <NUM>. In some embodiments, if the Sat(a) value is not monitored, the DMS <NUM> may be programmed to assume that it is <NUM>%.

The arterial oxygen tension value (PaO2) may also be manually entered. The PaO2 value is measured by the perfusionist on the arterial blood of the patient with blood gas analysis, using an adequate and specific device. In some embodiments, the arterial oxygen tension value may be continuously or discretely (every twenty minutes or so) monitored by an external device connected to the DMS <NUM>.

The gas flow value (Ve) may be manually entered. The Ve value is established by the perfusionist operating the heart-lung machine <NUM>. Generally, the Ve is regulated with a flow-meter, according to the patient's parameters. This Ve value rarely changes during a CPB procedure, and therefore can be manually inserted by the operator. However, as an alternative, the monitoring system <NUM> may include an electronic flow-meter connected to the heart-lung machine <NUM>, to continuously detect the Ve value.

In some embodiments, the DMS <NUM> may be configured to calculate and display the oxygen consumption rate (VO2) and/or the carbon dioxide production (VCO2). As noted above, the VO2 value may be calculated using equation <NUM> and the VCO2 value may be calculated using equation <NUM>: <MAT> <MAT>.

In some embodiments, the Ve value (gas flow) may be automatically and continuously acquired from a gas blender that is connected to the HLM <NUM>. In some instances, the Ve value may be manually entered into the DMS <NUM>. In some embodiments, the expired CO2 value (eCO2) may be continuously or discretely (about every twenty minutes or so) monitored by an external device connected to the HLM <NUM>. The eCO2 value may be separately monitored and manually entered into the DMS <NUM>.

In some embodiments, the monitoring device <NUM> is electrically connected to the HLM <NUM>, so as to continuously receive data collected by adequate sensors placed in specific positions of the heart-lung machine. Illustrative but non-limiting examples of continuously collected data include the patient's body temperature (T). The temperature T may be continuously measured by a temperature probe <NUM> inserted inside the esophagus or the rectum or other organs of the patient. The temperature probe <NUM> sends an electronic signal of the temperature to a monitor of the HLM <NUM> visualizing, in real-time, the temperature value. In this case, it is sufficient to interface with an electrical connection the monitor of the HLM <NUM> with the monitoring device <NUM>, for a continuous input of the temperature value T.

Another monitored value includes the exhaled carbon dioxide (eCO2). The eCO2 value is continuously measured through a CO2 detector <NUM> placed at the gas escape of the oxygenator <NUM> to detect the sidestream CO2 exhaled from the oxygenator <NUM>. The CO2 detector <NUM> can be any kind of CO2 detector among the various commercially available and re-usable capnographs.

Another monitored value includes the hematocrit (HCT). The HCT value is continuously measured through a hematocrit reading cell <NUM> placed inside the arterial or venous circuit of the HLM <NUM>. In some embodiments, the HCT value may be discretely measured, for example, about every twenty minutes or so by an external device that may be connected to the DMS <NUM>. In some embodiments, the HCT value may be independently monitored and manually inputted into the controller <NUM> and/or the DMS <NUM>. For instance, in <FIG>, the hematocrit reading cell <NUM> is placed inside the arterial line between the pump <NUM> and the oxygenator <NUM>. The hematocrit reading cell <NUM> is commercially available and disposable.

Another monitored value includes the pump flow rate (Qp). The Qp value is continuously measured through the Doppler reading cell <NUM>, placed on the arterial line of the HLM <NUM>. This kind of Doppler reading cell <NUM> measures the blood flow on the basis of the Doppler principle (red cells velocity).

In some embodiments, if the pump <NUM> is a centrifugal pump, it is already equipped with a Doppler reading cell <NUM>. Conversely, if the pump <NUM> is a roller pump, the Doppler reading cell <NUM> may be added. In the alternative, the Doppler reading cell <NUM> may be omitted, since the roller pump head is provided with a flow measuring system. In this case, the data regarding the pump flow Qp is directly sent to the monitoring device <NUM>.

With specific reference to <FIG>, operation of the monitoring system <NUM> is described below. The processor of the monitoring system <NUM> includes a first computing program <NUM> that, based on the weight and height of the patient as input by the operator calculates, according to pre-defined tables, the body surface area (BSA) of the patient.

The BSA value is sent to a second computing program <NUM> that receives the input value of the pump flow Qp as detected by the pump <NUM> of the HLM <NUM>. The second computing program <NUM> calculates the indexed pump flow Qpi, according to the relationship Qpl=Qp/BSA.

A third computing program <NUM> receives the input value HCT as detected by the hematocrit reading cell <NUM> placed inside the venous or arterial line of the heart-lung machine. The third computing program <NUM>, based on the equation (<NUM>), calculates the hemoglobin value Hb. The Hb value is sent to the display <NUM> and is displayed in a window <NUM> of the display <NUM> (<FIG>).

The pump flow indexed Qpi computed by the second computing program <NUM> and the hemoglobin value Hb computed by the third computing program <NUM> are sent to a fourth computing program <NUM> that receives as input values the values of arterial oxygen saturation (Sat(a)) and arterial oxygen tension (PaO2) manually entered by the operator. The fourth computing program <NUM>, according to the equation (<NUM>), calculates the indexed oxygen delivery value (DO2i).

As shown in <FIG>, the DO2i value is visualized in real time in a window <NUM> of the display <NUM> and as a graphical pattern <NUM> (as a function of time). The display <NUM> is provided with a chronometer window <NUM> showing the time passed from the beginning of the CPB.

As shown in <FIG>, the DO2i value is sent to a comparator <NUM> which compares it to a threshold value of DO2icrit that is displayed in a window <NUM> (<FIG>) of the display <NUM>. This threshold value may be set at <NUM>/min/m<NUM> at a temperature between <NUM> and <NUM>, and decreases as a function of temperature, in a linear fashion.

Therefore the threshold value of 002icrit be preset by the operator or may be calculated by a computing program <NUM> depending on the temperature value T determined by the temperature probe <NUM>. The temperature T value determined by the probe <NUM> is sent to the display <NUM> to be displayed in a window <NUM>.

When the DO2i value falls below the 002icrit, the comparing device sends a control signal to an alarm <NUM> that is triggered, alerting the operator of a potentially dangerous condition.

In some embodiments, the alarm <NUM> is not triggered by brief decreases of the pump flow Qp (often needed during CPB). Therefore, the alarm <NUM> could be set to be activated after <NUM> minutes of consecutive detection of a DO2i below the DO2i. However, a recording of all the periods of low flow can be made, to analyze and avoid the possibility that many short periods of low flow may create an additional effect. It is reasonable to consider no more than <NUM> minutes (as a total) of DO2i below the DO2icrit during a normal CPB lasting about <NUM> minutes. The monitoring device <NUM> is equipped with a computing program <NUM>, which receives as input values the exhaled carbon dioxide eCO2 as detected by the CO2 sensor <NUM> and the gas flow Ve set by the operator. According to these input data, the computing program <NUM> calculates the indexed carbon dioxide production VCO2i applying the equation (<NUM>).

The VCO2i value as calculated by the computing program <NUM> is sent to the display <NUM> and displayed in real time in a window <NUM> (<FIG>) in its graphical relationship <NUM> as a function of time.

The VCO2i value is sent to a second comparator <NUM> which compares it with an anaerobic threshold value VCO2icrit set by the operator; by default the VC02icrit is preset at <NUM>/min/m<NUM>. As shown in <FIG>, the display <NUM> is provided with a window <NUM> showing the value of anaerobic threshold VCO2icrit set by the operator.

Back to <FIG>, when the VCO2i exceeds the VCO2icrit an alarm signal is sent to a second alarm <NUM>, which, when triggered, alerts the operator of a warning condition. Moreover, as shown in <FIG>, the display <NUM> is provided with: a window <NUM> where the gas flow value Ve set by the operator is displayed; a window <NUM> where the indexed pump flow value Qpi arriving from the computing program <NUM> is displayed; and a window <NUM> where the body surface area of the patient is displayed as calculated by the computing program <NUM>.

In some embodiments, the monitoring system <NUM> may be equipped with a data recording system and a printer interface, and/or a digital data recording system. The display <NUM> could include two configurations: a complete configuration, as the one shown in <FIG>, and a reduced configuration, only considering the DO2 parameter, as shown in <FIG>.

In some embodiments, the DMS <NUM> may track and display a variety of different metabolic parameters. <FIG> and <FIG> are screen captures providing illustrative but non-limiting examples of some of the metabolic parameters that can be displayed by the DMS <NUM>. As discussed above, some of these parameters are measured while other parameters may be calculated by the DMS <NUM> using measured parameters. Examples of parameters include index oxygen delivery (DO2i), indexed oxygen consumption (VO2i), and indexed carbon dioxide production (VCO2i). Examples of ratios that may be displayed include DOi2/VCO2i, VCO2i/VO2i and VO2i/DO2i.

Claim 1:
An integrated perfusion system (<NUM>) comprising:
a heart lung machine (<NUM>) including
two to seven pump modules (<NUM>), each pump module having a control unit (<NUM>);
a controller (<NUM>) in communication with each control unit (<NUM>), wherein the controller is configured to operate the heart lung machine (<NUM>);
an input device (<NUM>) in communication with the controller (<NUM>) and configured to enter information that is not otherwise entered into the control units (<NUM>);
an output device (<NUM>) in communication with the controller (<NUM>) and configured to be used by the heart lung machine (<NUM>) to display pertinent information;
a data management system (<NUM>) in communication with the heart lung machine (<NUM>), the data management system including an RF sensor (<NUM>) and a processor (<NUM>) in communication with the RF sensor (<NUM>); and
one or more disposable elements (<NUM>) configured to be used in conjunction with the heart lung machine (<NUM>), each disposable element (<NUM>) including an RFID tag (<NUM>) programmed with identifying information for the one or more disposable elements (<NUM>) that can be read by the RF sensor (<NUM>);
characterized by:
wherein the identifying information is used to unlock an algorithm in the data management system depending on the identity of the one or more disposable elements (<NUM>);
wherein the algorithm monitors and/or provides data related to a patient's metabolism; wherein the data management system (<NUM>) is configured to track and display metabolic parameters.