An extracorporeal membrane oxygenation system

Abstract

An extracorporeal membrane oxygenation, ECMO, system (10) is provided, comprising a circulation unit (110) configured to cause blood to circulate through an extracorporeal circuit, an oxygenator (120) configured to oxygenate the blood circulating in the extracorporeal circuit, and a gas blender (130) configured to provide a gas flow, comprising oxygen, to the oxygenator. The system further comprises a control unit (140) configured to control the operation of the circulation unit and the gas blender, and an attachment structure (150) configured to releasably attach a housing (131) of the gas blender to a housing (111) of the circulation unit.

Description

[0001] AN EXTRACORPOREAL MEMBRANE OXYGENATION SYSTEM

[0002] Technical Field

[0003] The present invention relates to cardiovascular support, and more specifically to systems for extracorporeal membrane oxygenation, ECMO, also referred to as heartlung machines and cardiopulmonary bypass machines.

[0004] Background

[0005] Extracorporeal membrane oxygenation, ECMO, is a medical procedure used in cases of severe respiratory or cardiac failure. It involves temporarily bypassing or supporting a patient’s heart and lungs to oxygenate and remove carbon dioxide from the blood. Traditional ECMO systems typically utilise a wide variety of components and peripheral modules that are dependent on the patient’s need, the operator’s preferences for operational setup, and the use of various sensors and diagnostic equipment. Due to the extensive use of cables, fluid lines, mast-mounted pumps and other related devices, such as pump displays, that commonly are involved with such procedures, the cables and fluid lines become heavily intertwined and difficult to manage. Further, the variety of components and modules requires the operators to monitor and handle several user interfaces. This may lead to specific issues of operational inconvenience and time inefficiency for the operator, as well as limited mobility for the patient.

[0006] Therefore, there is a need for medical equipment, such as ECMO systems, having improved features that permit the operator to simplify the set-up and handling of the equipment.

[0007] Summary

[0008] In view of the above, it is thus an object of the present invention to overcome or at least mitigate the problems discussed above. In particular, it is an object to provide an improved ECMO system having the features set out in the independent claim.

[0009] Hence, according to a first aspect of the invention, there is provided an ECMO system comprising a circulation unit configured to cause blood to circulate through an extracorporeal circuit, an oxygenator configured to oxygenate the blood circulating the extracorporeal circuit, a gas blender configured to provide a gas flow, comprising oxygen, to the oxygenator, and a control unit configured to control the operation of the circulation unit and the gas blender. Further, an attachment structure is provided, configured to releasably attach a housing of the gas blender to a housing of the circulation unit.

[0010] The inventors have realised that by attaching the gas blender to the circulation unit, the physical connections between the circulation unit and the gas blender, such as fluid lines and cables for power supply and communication, may be simplified. While a free-standing gas blender, arranged spaced apart from the circulation unit, may require relatively extensive tubing and cabling that may become intertwined and difficult to handle, a circulation unit-mounted configuration of the system allows for a shorter physical distance to be bridged by the circulating fluids, electrical power, and data communication signals between the gas blender and the circulation unit. Further, attaching the gas blender to the circulation unit allows for a reduced number of separate components that need to be handled in case of transportation of the patient, as the gas blender and the circulation unit can be treated as a single component. Preferably, the oxygenator is attached to the circulation unit, or arranged in close vicinity of the circulation unit, to further reduce the length of the fluid lines carrying the gas flow between the gas blender and the oxygenator and simplify transportation and handling of the system.

[0011] According to some embodiments, the attachment structure is formed of a first mating structure of the housing of the circulation unit and a complimentary, second mating structure of the housing of the gas blender. The gas blender may hence be attached to the circulation unit by means of interlocking structures, in which complementary shapes or features of the gas blender and the circulation unit, respectively, fit together to form a secure attachment. Beneficially, the attachment structure may assist in ensuring that the gas blender remains safely attached to the circulation unit during mechanically challenging situations, such as inter-hospital patient transfer by helicopter or other transporting means. Helicopter transports are typically associated with exposure to relatively harsh conditions, such as vibrations and rain. Advantageously, the present embodiments may provide a combined setup of circulation unit and gas blender with rain protected housings and an attachment structure able to withstand the transport-induced vibrations. Several configurations of the attachment structure are possible. In an example, each of the first mating structure and the second mating structure includes a respective guiding edge or flange, wherein the guiding edge of the first mating structure is configured to engage the guiding edge of the second mating structure to fixate the gas blender to the circulation unit. In further examples, each of the first and second mating structures may include a substantially planar surface portion formed of the housing of the circulation unit and the housing of the gas blender, respectively. The guiding edges may be understood as features allowing the gas blender to be slid or inserted into the correct position on the circulation unit and may hence be configured to restrict relative motion between the gas blender and the circulation unit in at least one direction.

[0012] A spacing or separating gap may be provided between the gas blender and the circulation unit when the gas blender is attached to the circulation unit. The gap may be configured to allow a cooling air flow between the gas blender and the circulation unit.

[0013] According to an embodiment, the attachment structure may further comprise a locking mechanism configured to cooperate with the first and second mating structures to restrict relative motion between the first and second mating structures when the gas blender is attached to the circulation unit. The locking mechanism may be understood as a fastener, a snap lock, a spring-loaded protrusion, or a similar element. The locking mechanism may be arranged on the gas blender and configured to engage with a corresponding structure on the circulation unit or arranged on the circulation unit and configured to engage with a corresponding structure on the gas blender. The guiding edge and the locking mechanism may be configured to cooperate to restrict relative motion between the gas blender and the circulation unit in different directions, such as in the plane of the surface of the housings, or orthogonal to the plane. The attachment structure may further comprise a release mechanism allowing the operator to detach the gas blender from the circulation unit in a controlled manner. The release mechanism may, for example, be a push button causing the locking mechanism to release the engagement between the gas blender and the circulation unit.

[0014] Data communication and / or power supply may be provided via contact structures arranged on the interfacing surfaces of the gas blender and the circulation unit. The contact structures may, for example, comprise contact pads that are brought in contact with each other when the gas blender is attached to the circulation unit. In some embodiments, however, at least one of the data communication and the power supply may be provided by means of a cable connector extending between the gas blender and the circulation unit. The cable connector may advantageously provide a more flexible and reliable connection compared to the above-mentioned contact pads, as the latter may be more sensitive to alignment errors and poor mechanical fit between the gas blender and the circulation unit.

[0015] The data communication may be unidirectional, such as from the circulation unit to the gas blender, carrying instructions for controlling the operation of the gas blender. In other examples, the data communication may be bidirectional, allowing control instructions to be transmitted from the circulation unit to the gas blender, as well as feedback data, such as sensor data, to be supplied from the gas blender to the circulation unit. In further examples, the data communication may comprise event data relating to, e.g., problematic situations such as low input pressure.

[0016] In some embodiments, the ECMO system comprises a user interface, which may be arranged on the housing of the circulation unit. The user interface may be communicatively connected to the control unit and configured to convey operational information relating to the circulation unit and the gas blender. In some examples, the user interface may refer to a user interface of the control unit, wherein the user interface may be arranged on the circulation unit. The user interface may generally be understood as an interface module that provides a means for an operator, such as a healthcare provider, to interact with the ECMO system. The user interface enables the user to input commands or data into the system and receive output or feedback. The user interface may include physical controls such as buttons, switches, keys; touch-sensitive screens; and pointing devices like a mouse or a stylus. In particular, the user interface may be a graphical user interface, GUI, allowing visual presentation of information and user interaction through graphical elements. In some examples, the user interface comprises visual indicators, such as one or more LEDs. The visual indicators may, for example, indicate a functional status of the ECMO system. The user interface may in some examples comprise visual indicators only, i.e., no input means by which the operator can input commands or data into the system. In such case, the user interface may be understood to provide output or feedback only, i.e., one-way communication. Beneficially, the user interface may be common to the circulation unit and the gas blender, allowing the user to conveniently interact with both the gas blender and the circulation unit via a single interface, such as a single display.

[0017] The gas blender may be coupled to a plurality of gas sources, or gas storages, each supplying a different gas. One of the gas sources may, for example, supply the gas blender with air, while another one of the gas sources may supply the gas blender with medical oxygen. The gas from the gas sources may then be mixed, or blended, into a desired mixture that is provided to the oxygenator. For this purpose, a valve arrangement may be provided for controlling the gas flow supplied to the oxygenator. The valve arrangement may comprise a plurality of flow control valves associated with each of the gas sources. Each flow control valve may be configured to independently regulate the flow of its associated gas based on control signals received from the control unit.

[0018] In some embodiments, the valve arrangement may be an electrically controlled valve arrangement. The valve arrangement may comprise two or more electrically operated flow control valves, and a gas blender comprising such valves may accordingly be referred to an electronic gas blender. The electronic gas blender may be controlled by the control unit, which may determine operational variables for the individual valves of the valve arrangement as a function of parameter values adjusted by the operator and / or values received from sensors measuring the output from the gas blender and control the gas blender correspondingly. Thus, the operator can insert parameter values in an easy manner and do not elaborately have to calculate or find out by trying the parameter values, as may be the case with mechanical gas blenders.

[0019] In some embodiments, the valve arrangement is configured to bypass oxygen from the gas source to the oxygenator upon an operational failure of the gas blender. The bypassing may be achieved by the valve associated with the oxygen supply source switching to a bypass mode in which the gas flow is allowed to pass the valve arrangement without regulation. Beneficially, the bypassing reduces the risk of a poor oxygenation of the blood during, for example, power outages. In further embodiments, an emergency gas supply may be provided to supply the oxygenator with gas in case of an operational failure of the gas blender. In some examples, the emergency gas supply may be controlled by the operator. In some embodiments, the ECMO system comprises one or more sensors for generating feedback information to the control unit, which may be configured to adjust the operation of the gas blender based on the received feedback information.

[0020] The sensors may be employed to output a signal indicating the composition of the purge gas supplied to the oxygenator, i.e., the actual ratio of the individual gases, such as oxygen, in the purge gas. The determined gas contents may be compared with desired values that are pre-set by the operator, wherein the control unit can control the gas blender as a function of the result of this comparison in the form of a closed control loop such that the actual content of the respective gas corresponds to the pre-set desired value.

[0021] Additionally, the sensors can be employed to determine the flow rate of the purge gas passing through the oxygenator. In such case, the control unit may compare the determined actual value of the flow rate with a pre-set desired value and control the gas blender such that the actual flow rate corresponds to the desired value.

[0022] In particular, a difference between the actual values of the respective contents of the gases determined upstream and downstream of the oxygenator may be indicated, preferably graphically, to the operator, so that the operator can monitor how much carbon dioxide has been removed from the flow of blood or how much oxygen is supplied to the flow of blood. Hence, in some embodiments a first sensor may be arranged to generate a signal indicating an amount of oxygen supplied to the oxygenator and a second sensor may be arranged to generate a signal indicating an amount of oxygen discharged from the oxygenator. The sensors output may hence be used to determine a performance of the oxygenator, indicated by the gas transfer rate, and assist the operator in their decision to replace a poorly functioning oxygenator.

[0023] In some embodiments, the at least one of the first sensor and the second sensor forms part of the gas blender. The first and / or second sensor may hence be structurally integrated with the gas blender to simplify cabling and improve mobility of the system. In alternative examples, however, at least one of the sensors may be arranged external to the gas blender, such as along a fluid line connecting the gas blender to the oxygenator.

[0024] According to some embodiments, the gas blender comprises a pressure relief mechanism, also referred to as a safety valve or pressure relief valve, to protect the system and its components from damage due to overpressure. The relief mechanism may be configured to achieve this by releasing gas upon the pressure exceeding a certain predetermined limit, thereby preventing the build-up of excessive pressure that otherwise could lead to system failure of even explosion. The relief mechanism may be employed to protect the equipment, as well as the patient and medical staff. In some examples, the relief mechanism is a valve having an inlet connected to the gas blender, and an outlet that typically directs the released gas to a safe location.

[0025] According to some embodiments, the circulation unit may be a portable unit. Hence, the circulation unit may be designed to facilitate manual transportation, in which it is lifted and carried by medical staff. A handle may be provided to increase the user experience and facilitate handling of the circulation unit. By attaching the gas blender to the circulation unit, both components may be handled as a single item. Specifically, the circulation unit with the attached gas blender may be configured for inter-hospital transfer by road or air.

[0026] Other objects, features and advantages of the enclosed embodiments will be apparent from the following detailed description, from the attached dependent claims, as well as from the drawings. Those skilled in the art realise that different features of the present invention even if recited in different claims, can be combined in embodiments other than those described in the following.

[0027] Brief Description of the Drawings

[0028] Exemplifying embodiments will now be described in more details with reference to the appended drawings, on which: figure 1 is a schematic view of an ECMO system according to an embodiment of the present invention; figure 2 is a perspective view of a circulation unit and a gas blender according to an embodiment of the present invention; figure 3 is a perspective view of a circulation unit, a gas blender, and an oxygenator according to an embodiment of the present invention; figure 4a is a perspective view of a gas blender according to an embodiment of the present invention; figure 4b is a perspective view of a circulation unit according to an embodiment of the present invention; and figure 4c is a cross sectional portion of an attachment structure according to an embodiment of the present invention.

[0029] As illustrated in the figures, the sizes of the elements and features may be exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of the embodiments. Like reference numerals refer to like elements throughout.

[0030] Detailed Description

[0031] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0032] Figure 1 shows an ECMO system 10 according to an embodiment of the present invention. The ECMO system 10, which also may be referred to as an ECMO machine or heart-lung machine, may be understood as a piece of equipment used in critical care medicine to provide temporary support for patients with severe heart or lung failure. The main components of the ECMO system 10 include a circulation unit 110, which is configured to assist in circulating the patient’s 20 blood through an extracorporeal circuit formed by the ECMO system 10, an oxygenator 120 for oxygenating the blood, and a gas blender 130 supplying the oxygenator 120 with oxygen from a supply 138. Further, cannulas for connecting the patient’s blood vessels to the extracorporeal circuit and fluid lines, also referred to as circuit tubing 16, 17 for connecting the various components and carrying the patient’s blood through the ECMO system 10 may be provided.

[0033] The circulation unit 110 may for example comprise a roller pump or a centrifugal pump, depending on the specific type of ECMO system 10. Roller pumps typically comprises a rotating roller compressing a flexible tube or membrane. As the roller rotates, it squeezes the tube, creating a pulsatile flow of blood. Centrifugal pumps, on the other hand, use a rapidly rotating impeller to create a centrifugal force which pushes the blood outwards to generate a substantially continuous blood flow. Centrifugal pumps have been observed to reduce the risk for haemolysis, i.e., breakdown of red blood cells, and improved patient comfort.

[0034] The pump may be integrated in the circulation unit 110, such as arranged within a housing of the circulation unit 110 or attached to the housing. In alternative examples, the pump may be external to the circulation unit 110, such as a standalone pump, that may be controlled or operated by the circulation unit 110.

[0035] The circulation unit 110 may also comprise control circuitry 142, sensors, and a user interface 170, as will be discussed in greater detail later.

[0036] The oxygenator 120 is configured to facilitate exchange of oxygen and carbon dioxide between the patient’s blood and the gas mixture provided by the gas blender 130. The oxygenator 120 typically has a blood region 121 and a gas region 123 separated from the blood region 121 by a gas-permeable membrane 122. The extracorporeal flow of blood is passed through the blood region 121 according to the arrows Pl and P2, for which a supply line 16 and a discharge line 17 are provided. The supply line 16 and the discharge line 17 are connected to the circulation unit 110, by means of which the flow of blood through the blood region 121 is generated.

[0037] Several types of membranes 122 may be employed. In an example, the oxygenator 120 comprises a hollow fibre membrane, in which the blood flows in the blood region 121 inside the fibres and the gas mixture flows in the gas region outside the fibres. Oxygen and carbon dioxide exchange may occur across the membrane formed by the walls of the hollow fibres. In the example illustrated in figure 1, however, the membrane 122 is schematically illustrated as a sheet.

[0038] The gas mixture from the gas blender 130 is provided as a purge gas that is passed through the gas region 123 via inlet line 18 according to the arrow P3. Due to a partial pressure gradient, or a concentration difference, existing between individual components of the purge gas and the corresponding component in the flow of blood, this component is passed through the membrane 122 from the gas region 123 into the blood region 121 or vice versa. In particular, oxygen may be passed from the blood region 121 into the gas region 123 through the membrane 122, so that the flow of blood is oxygenated. Vice versa, carbon dioxide is passed from the blood region 121 into the gas region 123 through the membrane 122, so that carbon dioxide is removed from the flow of blood.

[0039] The purge gas P3 is supplied from an outlet 135 of the gas blender 110 to the oxygenator via inlet line 18. After the passage through the gas region 123 of the oxygenator 120, the purge gas can be discharged into the surrounding air or recycled. In some embodiments, the purge gas may be returned via a return line 19 to the gas blender 130, so that the purge gas can be used several times for flowing through the gas region 123.

[0040] The transfer capacity of the oxygen or the carbon dioxide, i.e., the amount of carbon dioxide or oxygen which is supplied to or removed from the flow of blood per unit of time depends, inter alia, on the flow rate of the flow of blood, the flow of volume of the purge gas, and the composition of the purge gas. In particular, the transfer capacity can be controlled via the composition of the purge gas. Therefore, it is desirable to adjust the composition, or mixture ratios, of the purge gas and the flow of the purge gas as precisely as possible.

[0041] Typically, the gas blender 130 comprises a plurality of inlets configured to receive medical gas from a respective gas source (collectively indicated by reference numeral 138). In the example shown in figure 1, the gas blender 130 comprises four inlets, of which a first one 133 may be configured to receive medical oxygen and a second one t 134 may be configured to receive air. It will be appreciated that the remaining two inlets are optional and may be used for supplying other types of gas, such as helium.

[0042] The oxygen may be supplied to the gas blender from an oxygen source 138, which may be an oxygen outlet of a hospital facility, a pressurised bottle of oxygen, or any other type of oxygen source suitable for delivering oxygen for medical applications. The same applies to the air, which may be supplied from a pressurised air outlet of a hospital facility, a pressurised bottle, or retrieved and pressurised from the surrounding air.

[0043] The gases from the individual gas sources 138 are mixed into a purge gas by a valve arrangement 132 and supplied via inlet line 18 to the gas region 123 of the oxygenator 120. The valve arrangement 132 may be configured to adjust the oxygen concentration based on the patient’s needs, allowing healthcare professionals to control the oxygen levels delivered to the patient. The valve arrangement 132 may be electronically controlled, utilising sensor input to achieve accurate gas mixtures.

[0044] Further, the system 10 may comprise a user inface 170 enabling the operator to input desired mixing ratios and monitor real-time sensor readings. The user interface 170 may be configured to display visual representations of the blending process, including graphical representations, charts, and alarms for abnormal conditions, facilitating effective monitoring and control. In an example, the user interface 170 comprises a field for displaying and setting a flow of blood in the extracorporeal circuit, a field displaying a rotation speed of a pump of the circulation unit 110, and a field for displaying and setting oxygen concentration and flow rate of the gas mixture delivered by the gas blender 130.

[0045] Each flow control valve may include a valve body having an inlet opening connected to its associated gas supply source, an outlet opening directed towards a common gas mixing chamber 139 or conduit of the gas blender, and a closure member or valve element that is movable between an open position, allowing gas flow from the inlet opening to the outlet opening, and a closed position, preventing such gas flow. The closure member’s position may be adjustable to vary the rate of gas flow, thereby controlling the proportion of each gas in the resultant gas mixture supplied to the oxygenator 120.

[0046] In an example, the valve arrangement 132 may be configured to switch to a bypass mode, or 'limp home’ mode, in which oxygen is bypassed from the gas source 138 directly to the oxygenator 120 upon operational failure of the gas blender 130. More specifically, the gas blender 130 may be configured to switch to the bypass mode in case of a power failure, thereby ensuring that the oxygenator is still supplied with oxygen.

[0047] Further, a pressure relief valve 190 may be provided to protect the system and its components from damage due to overpressure. The relief valve 190 may be configured to release excess pressure exceeding a predetermined limit and may be of a spring-loaded configuration, in which a spring force keeps the valve closed until the pressure exceeds the predetermined limit. The relief valve 190 may, for example, be arranged at the outlet 135 of the gas blender 130. In alternative configurations there may be provided a safety valve 190 instead, which is operable to shut off the gas supply in the outlet 135 in case of an overpressure.

[0048] It will be appreciated that the control unit 140 in some embodiments may be communicatively connected to the circulation unit 110, thereby allowing an operation of the circulation unit 110 to be controlled via the control unit 140 and the user interface 170. The control unit 140 may, for example, be configured to control pump parameters regulating the blood flow in the extracorporeal circuit formed by the ECMO system 10.

[0049] The system 10 may further comprise sensors for generating feedback information to the control unit 140. In the present example, the system 10 comprises a first sensor 181 arranged upstream of the oxygenator 120 in the region of the supply line 18 and a second sensor 182 arranged downstream of the oxygenator 120 in the region of the return line 19. The sensors 181, 182 may be used to determine the composition of the purge gas, i.e., the actual value of the contents of the individual gases in the purge gas. The determined actual values may be compared with the desired values that have been pre-set by the operator, whereby the control unit 140 may control the gas blender 130 based on the result of the comparison. The sensor data may be used as feedback in a closed loop control such that the actual content of the respective gas converges to the predetermined desired value.

[0050] Additionally, the sensors 181, 182 may be used to determine the flow rate of the purge gas, wherein the control unit 140 preferably compares the determined actual value of the flow rate with the pre-set desired value and controls the individual proportional values such that the actual flow rate converges towards the desired value.

[0051] Additionally, or alternatively, the actual values determined via the sensors 181, 182 can also be shown to the operator via the touch screen, so that the operator can easily monitor the operation of the system 10. In particular, a difference between the actual values of the respective contents of the gases determined upstream and downstream of the oxygenator 120 may be indicated, preferably graphically, to the operator, so that the operator can monitor in an easy manner how much carbon dioxide has been removed from the flow of blood or how much oxygen is supplied to the flow of blood.

[0052] The first sensor 181 may be arranged at an outlet 135 of the gas blender 130, an inlet of the oxygenator 120, or along a fluid line 18 between the gas blender 130 and the oxygenator 120. Similarly, the second sensor 182 may be arranged at a recirculation inlet of the gas blender 130, an outlet of the oxygenator 120, or along a fluid line 19 between the oxygenator 120 and the gas blender 130. In an example, at least one of the sensors 181, 182 is integrated in the gas blender 130. In another example, at least one of the sensors 181, 182 is an external sensor, i.e., a separate component external to the gas blender 130. In further examples, the sensing element of at least one of the sensors 181, 182 may be external to the gas blender 130, while the electronics responsible for processing, communicating and interpreting the electrical signal from the sensing element may be integrated in the gas blender 130. Integrating at least parts of the sensor(s) 181, 182 in the gas blender 130 or the circulation unit 110 may beneficially reduce the complexity of the cabling required to connect the sensors 181, 182.

[0053] Several types of sensors may be employed in the ECMO system 10. The selection of sensor type depends, inter alia, on the specific requirements of the ECMO system 10, the capabilities of the control unit 140, and for which parameters there is an interest to monitor. Examples of sensor types include flow sensors, gas composition sensors, pressure sensors, temperature sensors, and oxygen sensors. By providing one or several sensors, such as the first sensor 181 and the second sensor 182 discussed above, real-time feedback on the gas mixture supplied to the oxygenator 120 as well as the gas returned from the oxygenator 120 may be obtained, allowing for improved control and adjustment of the blending process. The output from the first and second sensors 181, 182 may, for example, be compared to determine the amount of oxygen the patient 20 has taken up via the blood. This information may in turn be used as feedback in a closed loop control of the gas blender 130.

[0054] The control unit 140 may be arranged in or at the circulation unit 110, such as within the housing of the circulation unit 110, or external to the circulation unit 110. In an example, the control unit 140 may be arranged in an external server arranged at a different physical location, such as in a control centre communicating with the ECMO system 10 over a local area network, or in a cloud-based server application. The control unit 140 may comprise circuitry 142 configured to carry out functions of the control unit 140, such as processing functions, calculations of mixing ratios, and parameter values for operating the circulation unit 110 and the gas blender 130. The circuitry 142 may comprise a processor, such as a central processing unit, CPU, microcontroller, or microprocessor configured to execute program code.

[0055] Figure 2 is a perspective view of a circulation unit 110 and a gas blender 130 according to an embodiment of the present invention. The circulation unit 110 and the gas blender 130 may be similarly configured as the corresponding components discussed above in connection with figure 1. In the present example, a housing 131 of the gas blender 130 has been attached to a housing 111 of the circulation unit 110, such that the gas blender 130 and the circulation unit 110 form a common, structurally integrated unit. The gas blender 130 is attached to a lateral side of the circulation unit 110 and oriented such that its gas inlets 133, 134 and outlet are facing towards the back of the circulation unit 110, where the oxygenator 120 (not shown) may be arranged. By the ‘back’ of the circulation unit 110 is understood the side of the circulation unit 110 facing away from the operator handling the user interface 170. Further, the gas blender 130 may be provided with a shock protection structure or bumper 137 arranged at or around one or more edges of the housing 131 to absorb impacts and mechanical shocks. The bumper 137 may, for example, be formed of rubber.

[0056] By attaching gas blender 130 to the circulation unit 110, the gas blender 130 can be connected to the oxygenator 120 by means of a relatively short fluid line compared to configurations in which the gas blender 130 is a freestanding component. The same applies to electrical power supply, which may be provided from the circulation unit 110, as well as to data communications between the gas blender 130 and the circulation unit 110. Data communications and / or power supply may for example be provided by means of a mechanical interface between the gas blender 130 and the circulation unit 110, for example comprising electrical contact pads that are brought into electrical contact when the gas blender 130 is attached to the circulation unit 110, or by means of a cable connector (not shown) extending between the gas blender 130 and the circulation 110.

[0057] The user interface 170 may be common to the circulation unit 110 and the gas blender 130. An operator may hence use the user interface 170 for monitoring operational parameters of both the circulation unit 110 and the gas blender 130, as well as adjusting control parameters and settings of the circulation unit 110 and the gas blender 130. The circulation unit 110 may further comprise a handle 112, by which the circulation unit 110 and the attached gas blender 130 can be handled and transported as a single item by an operator. Hence, the circulation unit 110, the gas blender 130 and, optionally, the oxygenator 120 may form a single, portable unit.

[0058] Further, protective frame elements 113, 114, forming a ‘roll cage’, may be provided to protect the backside of the oxygenator 120, and equipment such as the oxygenator, from mechanical damage during handling and transport.

[0059] The gas blender 130 may be releasably attachable to the housing 111 of the circulation unit 110 to allow an operator to remove or replace the gas blender 130 when desired. The attachment may be achieved by interlocking structures, forming an attachment structure 150 in which complementary shapes or features on the housing 111 of the circulation unit 110 and the housing 131 of the gas blender 130 fit together to form a secure connection. Such complementary shapes may include tabs, slots, grooves, or protrusions. When the interlocking structures are aligned and brought together, they may engage to create a stable attachment. Alternatively, or additionally, the attachment structure comprises fasteners, such as screws, bolts, nuts, or rivets. The fasteners may be inserted through corresponding holes or grooves to attach the gas blender 130 to the circulation unit 110. Further examples of attachment structures may include snap locks, typically involving spring loaded elements which, when pushed or pressed together, engage to produce an attachment. In further examples, a magnetic attachment may be utilised to fixate the gas blender 130 to the circulation unit 110.

[0060] Figure 3 is another perspective view of the circulation unit 110 and gas blender 130 in figure 2. In figure 3, however, an oxygenator 120 has been attached to the circulation unit 110. The oxygenator 120 may be attached to the back of the circulation unit 110, where it may be protected by the frame elements 113, 114.

[0061] The gas blender 130 comprise a first inlet 133 for supply of medical oxygen from an oxygen supply (not shown), a second inlet 134 for supply of air from an air supply (not shown), and an outlet 135 for the purge gas that is to be supplied to the oxygenator 120. A fluid line may be provided to connect the outlet 135 of the gas blender 120 to an inlet of the oxygenator 120 (not shown). The inlets 133, 134 may comprise standardised connectors such as NIST connectors (National Institute of Standards and Technology) or DISS connectors (Diameter Index Safety System). However, other type of fittings are also possible, such as quick coupling connectors.

[0062] Further, the gas blender 110 comprises a contact structure 136 for data communication and / or electric power supply. The contact structure 136 may be connected to a cable connector (not shown) connecting the gas blender 130 to the circulation unit 110.

[0063] The oxygenator 120 comprises a gas return outlet 19’ for returning the purge gas to the gas blender 130, as well as fluid line connections 16’, 17’ for the blood circulating in the extracorporeal circuit and water connectors 15 for circulation of a temperature regulating water flow.

[0064] Figure 4a is a perspective view of the underside of the gas blender 130, i.e., the substantially planar portion of the surface of the housing 131 arranged to face the housing of the circulation unit 110. This side may also be referred to as the ‘belly’ of the gas blender 130. Further, a plurality of slits or fan openings 156 may be provided in the underside, thereby allowing letting cooling air and / or gas from the pressure relief valve to escape the interior of the gas blender 130.

[0065] The substantially planar underside of the gas blender 130 forms a second mating structure 152 of the attachment structure 150, which is configured to releasably attach the gas blender 130 to the circulation unit 110. The second mating structure 152 may further comprise a guiding edge, or flange 152’, protruding from the substantially planar surface portion and extending along at least a portion of an edge of the gas blender 130. The guiding edge 152’ is configured to engage a corresponding structure on the housing 111 of the circulation unit 110 to secure the gas blender 130 to the circulation unit 110. A detailed view of an example of such interlocking guiding edges is shown in figure 4c.

[0066] The attachment structure may further comprise a locking mechanism 154 configured to cooperate with the second mating structure 152 to restrict relative motion between the first and second mating structures when the gas blender 130 is attached to the circulation unit 110. The locking mechanism 154 may comprise a protruding member, such as a spring-loaded pin or wedge 154, configured to engage a corresponding groove or indentation of the housing 111 of the circulation unit 110 to hinder the gas blender 130 from sliding along the housing 111 of the circulation unit 110. The guiding edge 152’ and the locking mechanism 154 may hence cooperate to maintain the gas blender 130 in its intended position.

[0067] The locking mechanism 154 may further comprise a release mechanism 155, which may be configured as a push button by means of which the operator may release the engagement between the protruding member and the corresponding groove or indentation in the housing 111 of the circulation unit 110 to detach the gas blender 130 from the circulation unit 110. The release mechanism 155 may be arranged on the side of the gas blender 130 facing the circulation unit 110, and preferably at a portion arranged to allow the release mechanism 155 to be accessed by the operator when the gas blender 130 is attached to the circulation unit 110. The release mechanism 155 may, for example, be arranged at a portion of the planar surface portion of the gas blender 130 that extends beyond the corresponding planar surface portion of the housing 111, to which the gas blender 130 is attached, such that the release mechanism 155 can be accessed via the overhanging portion.

[0068] Figure 4a also illustrates the gas inlets 133, 134 for supply of oxygen and air from the gas sources (not shown), as well as the outlet 135 for release of mixed purge gas to the oxygenator 120. The gas inlets 133, 134 and the outlet 135 may be arranged on a lateral side of the gas blender 130 facing the back of the circulation unit 110 when attached to the circulation unit 110. The same lateral side may comprise contact points 136 for data communication and / or electrical power supply.

[0069] Figure 4b is a perspective view of the circulation unit 110 when the gas blender 130 is detached. Figure 4b shows the first mating structure 151 of the housing 111 of the circulation unit 110, comprising a substantially planar surface portion and, in this example, two guiding edges 151’ that are complementary to the guiding edges 152’ of the gas blender 130 shown in figure 4a. The complimentary guiding edges 151’, 152’ may be configured to allow the gas blender 130 to be slid into the correct position, in which the guiding edges 151’, 152’ may prevent the gas blender 130 to move in a direction parallel to the planar surface portions (to the left in figure 4b) as well in a direction orthogonal to the planar surface portions. Further, the locking mechanism 154 of the gas blender may be brought into engagement with a recess 154’ in the housing 111 of the gas blender 130 so as to hinder the gas blender 130 from being detached from the circulation unit 110 (in a direction to the right in the figure). Figure 4c shows an example of interlocking guiding edges for securing the gas blender 130 to the housing 111 of the circulation unit 110. The first mating structure 151 may comprise a first guiding edge, or rib 151’ protruding from the circulation unit 110 and comprising a concave surface portion facing the housing 111. The second mating structure 152 may comprise a second guiding edge, or rib 152’, having a complimentary concave surface portion facing the housing of the gas blender 130. When the gas blender 130 is pushed into its intended position, the concave surface portions of the first and second guiding edges 151’, 152’, respectively, may be brought into contact with each other and form a connection that hinders the gas blender 130 from moving at least in a two directions - a first, downward direction parallel to the planar surfaces portion of the first and second mating structures 151, 152 (downward in the figure) and a second direction orthogonal to the planar surface portions (to the right in the figure). Movement in other directions may be hindered by a locking mechanism 154, 154’ as discussed above. The housings 111, 131 may be spaced apart by a distance d to allow a cooling airflow in the gap between the housing 111, 131.

[0070] Thus, in the drawings and the specification are disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. The scope of the invention is set forth in the following claims, in which the word ‘comprising’ does not exclude other elements or steps, and the indefinite article ‘a’ or ‘an’ does not exclude a plurality.

Claims

CLAIMS1. An extracorporeal membrane oxygenation, ECMO, system (10), comprising: a circulation unit (110) configured to cause blood to circulate through an extracorporeal circuit; an oxygenator (120) configured to oxygenate the blood circulating in the extracorporeal circuit; a gas blender (130) configured to provide a gas flow, comprising oxygen, to the oxygenator; a control unit (140) configured to control the operation of the circulation unit and the gas blender; and an attachment structure (150) configured to releasably attach a housing (131) of the gas blender to a housing (111) of the circulation unit.

2. The ECMO system according to claim 1, wherein the attachment structure comprises interlocking structures formed of a first mating structure (151) of the housing of the circulation unit and a complimentary, second mating structure (152) of the housing of the gas blender.

3. The ECMO system according to claim 2, wherein the first mating structure includes a first guiding edge (151 ’) and the second mating structure includes a second guiding edge (152’), wherein the first guiding edge is configured to engage the second guiding edge to fixate the gas blender to the circulation unit.

4. The ECMO system according to claim 2 or 3, wherein the first mating structure includes a substantially planar surface portion of the housing of the circulation unit and the second mating structure includes a substantially planar surface portion of the housing of the gas blender.

5. The ECMO system according to claim 4, wherein the respective surface portions are configured to be oriented substantially parallel and spaced apart when the gas blender is attached to the circulation unit.

6. The ECMO system according to any of claims 2 to 5, wherein the attachment structure further comprises a locking mechanism (154, 154’) configured to cooperate with the first and second mating structures to restrict relative motion between the first and second mating structures when the gas blender is attached to the circulation unit.

7. The ECMO system according to any of the preceding claims, further comprising a cable connector for data communication and / or transfer of electrical power between the circulation unit and the gas blender.

8. The ECMO system according to any of the preceding claims, wherein the system further comprises a user interface (170) arranged on the housing of the circulation unit, wherein the user interface is communicatively connected to the control unit and configured to convey operational information relating to the circulation unit and the gas blender.

9. The ECMO system according to any of the preceding claims, wherein the gas blender comprises an electrically controlled valve arrangement (132) for controlling the gas flow provided to the oxygenator.

10. The ECMO system according to claim 9, wherein the valve arrangement is configured to bypass oxygen gas upon an operational failure of the gas blender.

11. The ECMO system according to any of the preceding claims, further comprising at least one of a first sensor (181) configured to generate a signal indicating an amount of oxygen supplied to the oxygenator; or a second sensor (182) configured to generate a signal indicating an amount of oxygen outputted from the oxygenator.

12. The ECMO system according to claim 11, wherein the control unit is configured to adjust the operation of the gas blender based on the signals received from the first sensor and the second sensor.

13. The ECMO system according to claim 11 or 12, wherein the first sensor and the second sensor form part of the gas blender.

14. The ECMO system according to any of the preceding claims, wherein the gas blender further comprises a relief mechanism (190) configured to limit excessive pressure within the gas blender.

15. The ECMO system according to any of the preceding claims, wherein the circulation unit is portable.

Images