Collection of priming fluid for extracorporeal blood circuits

Abstract

The present disclosure provides a fluidic device for use in an extracorporeal body fluid system, comprising a sample flow path through which a body fluid can flow, and a cleaning fluid unit configured to provide a biocompatible cleaning fluid upstream to the sample flow path.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to fluidic devices for use in extracorporeal body fluid systems, sensor systems for use in extracorporeal body fluid systems, and methods of operating fluidic devices. [Background technology]

[0002] Extracorporeal fluid systems, such as extracorporeal blood circuits, are used to withdraw fluid from a patient's body before returning it to the patient or to another patient. Such systems may be used in treatment systems to treat or modify the fluid, or may be used as a bypass while an organ is being manipulated. Examples of the former systems include dialysis (hemodialysis) and autotransfusion, while examples of the latter systems include cardiopulmonary bypass (heart-lung machine) or extracorporeal membrane oxygenation (ECMO) devices. Other extracorporeal fluid systems include systems that provide fluid (or components of fluid) from a donor before transfer to a recipient.

[0003] Typically, sensors are used in these circuits to monitor bodily fluids. For example, they can be used to monitor the levels of various analytes, such as ions, monitor temperature, pH, conductivity, etc. This can provide information about the patient's condition and the progress of any treatment. Some of these sensors are directly in-line with the circuit and continuously monitor parameters. However, they suffer from drawbacks such as drift and lack of sensitivity.

[0004] Other sensors sample portions of bodily fluid at specific intervals, for example by drawing a portion of the fluid into a separate sampling fluid path. This can be advantageous because the sensing process can be carried out over a longer period of time, increasing sensitivity, and the sensor can be stored in calibration fluid between measurements to ensure or improve accuracy.

[0005] However, these sensors suffer from problems related to the use of bodily fluids, lack of continuous flow, and downtime between measurements. For example, bodily fluids such as blood can clot in the sensor fluid path, such as the sampling fluid path, causing blockages and narrowing. If a valve is used, this can lead to valve blockage and sensor failure. Contamination can also occur.

[0006] It would be advantageous to provide a fluid path that does not suffer from these problems. Summary of the Invention [Means for solving the problem]

[0007] The present disclosure provides a fluidic device for use in an extracorporeal body fluid system, comprising a sample flow path through which a body fluid can flow, and a cleaning fluid unit configured to provide a biocompatible cleaning fluid upstream to the sample flow path.

[0008] In one embodiment, a fluidic device for use in an extracorporeal body fluid system having a circulating fluid flow path includes: a sample flow path having an inlet and a sensor assembly interface downstream of the inlet, where the inlet is for receiving body fluid from the circulating fluid flow path and the sensor assembly interface is for providing body fluid to the sensor assembly; a sampling valve disposed along the sample flow path and configured to selectively allow fluid flow along the sample flow path between the inlet and the sensor assembly interface; and a washing unit for washing body fluid from at least a portion of the sample flow path. The washing unit includes a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; and a washing fluid delivery unit configured to provide the biocompatible washing fluid from the washing fluid reservoir to the sample flow path. During use, the fluidic device is configured such that the washing fluid delivery unit flows the biocompatible washing fluid upstream from the washing fluid reservoir to the inlet of the sample flow path.

[0009] In one embodiment, a sensor system for use in an extracorporeal body fluid sensing system comprises a fluidic device according to any of the embodiments described herein and a control unit configured to operate the fluidic device to flow a biocompatible cleaning fluid upstream from a cleaning fluid reservoir to an inlet of a sample flow path. The control unit may thus be configured to control the cleaning device and the collection valve, and may further control the operation of any further devices in or connected to the flow path, such as valves or pumping mechanisms.

[0010] In one embodiment, a method of operating a fluidic device comprises: providing a fluidic device comprising: a sample flow path having an inlet and a sensor assembly interface downstream of the inlet, the inlet for receiving bodily fluid from a circulating fluid flow path and the sensor assembly interface for providing the bodily fluid to the sensor assembly; a sampling valve disposed along the sample flow path, the sampling valve configured to selectively allow fluid to flow along the sample flow path between the inlet and the sensor assembly interface; a washing unit for washing bodily fluid from at least a portion of the sample flow path, the washing unit comprising: a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; and a washing fluid delivery unit configured to provide the biocompatible washing fluid from the washing fluid reservoir to the sample flow path; flowing the body fluid from the inlet of the sample flow channel to the sensor assembly interface; and flushing the sample flow path to remove bodily fluids by flowing a biocompatible flushing fluid upstream from a flushing fluid reservoir to the inlet of the sample flow path.

[0011] The invention will now be described in more detail with reference to the accompanying drawings, which are not intended to be limiting. [Brief explanation of the drawings]

[0012] [Figure 1] 1 provides a schematic plan view of a fluidic device according to an embodiment. [Figure 2] 1 provides a schematic plan view of a sensor system according to an embodiment. [Figure 3A] 2 provides a schematic plan view of the fluidic device of FIG. 1 used in one embodiment. [Figure 3B] 2 provides a schematic plan view of the fluidic device of FIG. 1 used in one embodiment. [Figure 3C]2 provides a schematic plan view of the fluidic device of FIG. 1 used in one embodiment. [Figure 3D] 2 provides a schematic plan view of the fluidic device of FIG. 1 used in one embodiment. [Figure 4A] 2 provides a schematic plan view of the fluidic device of FIG. 1 used in one embodiment. [Figure 4B] 2 provides a schematic plan view of the fluidic device of FIG. 1 used in one embodiment. [Figure 5] 1 provides a schematic depiction of an extracorporeal body fluid device in use;

[0013] [Figure 6] 1 is a schematic plan view of a fluidic device according to an embodiment; [Figure 7] 1 depicts a method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Extracorporeal fluid circuits, such as extracorporeal blood circuits, are used to withdraw bodily fluids from a patient's body before returning them to the patient or to another patient's body. These circuits incorporate or use sensors to monitor the bodily fluids. One type of sensor is used in systems that sample portions of the bodily fluid at intervals by withdrawing a portion into a separate sample flow path. These types of sensors suffer from problems related to the use of bodily fluids, lack of continuous flow, and downtime between measurements. For example, bodily fluids such as blood can clot in the sampling fluid path or in the sensor fluid path, such as dead space in a valve, causing blockages and narrowing. When valves are used, this can lead to valve blockage and sensor failure. Contamination can also occur.

[0015] It would be advantageous to provide a fluid path that does not suffer from these problems.

[0016] In one embodiment, a fluidic device for use in an extracorporeal body fluid system having a circulating fluid flow path includes: a sample flow path having an inlet and a sensor assembly interface downstream of the inlet, where the inlet is for receiving body fluid from the circulating fluid flow path and the sensor assembly interface is for providing body fluid to the sensor assembly; a sampling valve disposed along the sample flow path and configured to selectively allow fluid flow along the sample flow path between the inlet and the sensor assembly interface; and a washing unit for washing body fluid from at least a portion of the sample flow path. The washing unit includes a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; and a washing fluid delivery unit configured to provide the biocompatible washing fluid from the washing fluid reservoir to the sample flow path. During use, the fluidic device is configured such that the washing fluid delivery unit flows the biocompatible washing fluid upstream from the washing fluid reservoir to the inlet of the sample flow path.

[0017] The embodiments provide a fluidic device that avoids the aforementioned problems related to the accumulation and contamination of bodily fluids in portions of the sample flow path (e.g., within the flow path or within a valve) and associated flow paths, thus improving the reliability of the fluidic device and associated sensors.

[0018] In particular, the device is configured (or operable) to drain body fluid at least upstream of the sample flow path from the sample flow path into the circulation fluid flow path. This allows areas of the fluidic device and sensor assembly in open and direct contact with body fluid in the circulation fluid flow path returning to the patient (e.g., upstream of the sampling valve and any flow path upstream of the sampling valve) to be cleaned of residue or contaminants, such as clotted blood. This has a significant advantage over devices that provide the associated sensor assembly with calibration or flushing fluids used only to clear downstream portions, which may otherwise risk device failure due to clotting or clogging (e.g., valve failure) or further sample contamination. Extracorporeal body fluid systems are often connected to patients for hours or even days, requiring continuous, automated sampling and sensing without failure.

[0019] It should be understood that strict regulations regarding contamination and patient health mean that only regulatory-approved fluids can be introduced to a patient. Embodiments provide fluidic devices having a fluid reservoir (e.g., a sterile reservoir) capable of storing a biocompatible fluid, configured to be provided in an upstream direction (e.g., through the use of a valve), such that the biocompatible fluid can clear the entire upstream flow path without fear of contaminating the patient's bodily fluid with an inappropriate fluid. That is, the biocompatible fluid herein can clear the upstream portion of the sample flow path and any upstream-facing components or surfaces before being safely returned to the circuit and then returned to the patient. The latter also reduces the volume required to store biowaste that would otherwise be discharged as waste.

[0020] The fluid device is for an extracorporeal body fluid system that includes a circulating fluid flow path. A circulating fluid flow path in an extracorporeal body fluid sensing system refers to a fluid flow path that extracts body fluid from a patient and then returns the fluid to the patient (e.g., in a circulating manner). An extracorporeal body fluid system may also use a fluid flow path that is used to extract body fluid from a patient and return it to another location. Body fluids may be treated or modified during circulation. The circulating fluid flow path may consist of several flow paths in parallel and / or series and may include passing body fluid through a treatment device or system. Examples of systems that incorporate such a circulating fluid flow path include dialysis or extracorporeal membrane oxygenation (ECMO) systems. In an embodiment, an extracorporeal body fluid sensing system is provided that includes a fluid device disclosed herein and a circulating fluid flow path in fluid communication with the fluid device.

[0021] In some embodiments, the bodily fluid is blood. Examples of systems for extracting and returning blood include dialysis (hemodialysis) and autotransfusion, cardiopulmonary bypass (heart-lung machine) or extracorporeal membrane oxygenation (ECMO) devices. Blood returned to the patient is subject to strict requirements, e.g., it should not be compromised by contamination with cleaning fluids.

[0022] The inlet is connectable to such a circulating fluid flow path to receive bodily fluid therefrom. Sampling from the circulating fluid flow path can occur at discrete time intervals and can be automated. The sensor assembly interface can be an outlet, e.g., an outlet for a sensor assembly or an outlet in fluid connection with the sensor assembly, or it can be a portion of the sample flow path. The latter can be a portion of the sample flow path that has an opening or hole in fluid communication with the sensor assembly, or the sensor assembly can be received within this portion of the sample flow path (forming the sensor assembly interface).

[0023] The fluidic device uses a flushing fluid that is a biocompatible fluid, i.e., a fluid (e.g., liquid) that can be safely provided to a patient (in admixture with bodily fluids) and is not harmful to the patient. In one embodiment, the biocompatible fluid is saline or an infusion solution.

[0024] In one embodiment, the first junction is downstream of the collection valve in the sample flow path. By downstream, we mean that the first junction is toward the sensor assembly interface, so that it is fluidly connected to the sample flow path at a point between the collection valve and the sensor assembly interface. This means that during use, the cleaning fluid delivery unit directs a biocompatible cleaning fluid upstream along the sample fluid flow path, through the collection valve, and into the inlet of the sample flow path. The valve has moving parts through which bodily fluids flow and is therefore at risk of contamination and clogging. For example, blood remaining in the dead space of the valve is prone to clotting and can cause the valve to stick. Passing the cleaning fluid through the valve clears the valve, reducing the risk of failure. Furthermore, cleaning in this manner is preferable to cleaning systems that use a downstream cleaning system because it cleans surfaces upstream of the valve, allowing the valve to be cleaned in the open position, ensuring that all surfaces that come into contact with bodily fluids are cleaned. The downstream portion of the valve can be cleaned by the downstream fluid, but the upstream portion cannot be cleaned and the valve must remain closed to prevent return of this non-biocompatible calibration fluid. Furthermore, these embodiments are advantageous because only the patient-facing surfaces need to be cleared with biocompatible fluid, and lower cost or more optimal fluids for cleaning and / or calibration can be used in the remainder of the fluidic device and sensor assembly (e.g., with the sampling valve closed).

[0025] In one embodiment, the fluidic device further comprises a sensor assembly control valve disposed between the first junction and the sensor assembly interface, the sensor assembly control valve configured to selectively allow fluid flow along the sample flow path between the first junction and the sensor assembly interface. In other words, the sensor assembly control valve is provided downstream of the first junction but upstream of the sensor assembly interface.

[0026] In embodiments, the fluidic device is configured such that, during use, the sample assembly control valve is closed to prevent wash fluid from flowing to the sensor assembly interface, thus preventing flow to the associated sensor assembly. This helps to speed up the wash process and ensures separation of the calibration fluid over the sensor assembly from bodily fluids that are returned to the circulation fluid flow path.

[0027] These embodiments also have the advantage of allowing the biocompatible reservoir and sample flow path upstream of the sensor assembly control valve to be isolated from downstream components, so that a non-biocompatible fluid (e.g., a calibration fluid or a wash fluid) can be used to clear the fluid portion downstream of the sensor assembly control valve, reducing the volume requirements (and therefore storage costs and complexity) of the biocompatible fluid.

[0028] In one embodiment, the device further comprises a calibration fluid unit including a calibration fluid reservoir for receiving a calibration fluid, the calibration fluid reservoir fluidly connected to the sample flow path at the second junction and a calibration fluid delivery unit configured to provide the calibration fluid to the sample flow path. The fluidic device may be configured such that, during use, the calibration fluid delivery unit flows from the downstream calibration fluid reservoir to the sensor assembly interface of the sample flow path. The device may further comprise a calibration fluid reservoir valve at the second junction and configured to control the flow of calibration fluid from the calibration fluid reservoir to the sample flow path.

[0029] In one embodiment, the first junction is upstream of the second junction. In other words, the wash fluid reservoir of the wash unit is fluidly connected to the sample fluid path at a location upstream of where the calibration fluid reservoir is fluidly connected to the sample fluid path. This reduces the risk of calibrating fluid, such as that trapped in dead space around the second junction or along the sample flow path, being swept into the circulating fluid path and thus contaminating bodily fluids.

[0030] In one embodiment, a valve is located in the sample flow path between the first and second junctions to selectively allow fluid flow along the sample flow path. In some embodiments, this may be a collection valve. In other embodiments, this may be an additional valve.

[0031] In one embodiment, the wash unit is operable to draw fluid from the sample flow path into the wash fluid reservoir. Prior to use with a patient, extracorporeal body fluid sensing systems are typically filled with a biocompatible fluid, such as saline. This biocompatible fluid is also typically provided to the fluidic device of the associated sensing system. By providing a wash unit operable (or configured) to draw fluid from the sample flow path, it is possible to draw this biocompatible fluid into the reservoir and then use this stored fluid for the wash process. This eliminates the need to store the biocompatible fluid within the fluidic device itself prior to use, which could significantly increase manufacturing complexity and cost and require regulatory approval for the fluidic device. In other embodiments, it may be drawn from a separate source prior to use, such as a saline bag. These embodiments are still beneficial because they avoid the need to provide the fluidic device with a biocompatible fluid during manufacture, as the biocompatible fluid can be obtained at the time of use. In alternative or additional embodiments, the wash fluid reservoir may be provided with the wash fluid during manufacture, for example, the wash fluid reservoir may contain a biocompatible wash fluid. In some specific embodiments, the wash unit may comprise an actuator configured to draw fluid from the sample flow path, such as a pump or syringe.

[0032] In one embodiment, the fluidic device further comprises a sensor assembly, and the sensor assembly interface of the sample flow path is in fluid communication with the sensor assembly. Thus, the fluidic device is configured so that a fluid, such as a bodily fluid or a calibration fluid, provided in the sample flow path can be provided to the sensor assembly through the sensor assembly interface. The sensor assembly comprises at least one sensor (or transducer) configured to measure a property of the fluid provided thereto.

[0033] In one embodiment, the fluidic device is further configured such that, during use, the cleaning fluid delivery unit flows a biocompatible cleaning fluid from the cleaning fluid reservoir downstream through the sample flow path. This may be to the sensor assembly interface or to another outlet, such as a waste reservoir. Cleaning in both directions cleans the valve in all positions, thereby further reducing the risk of contamination.

[0034] In one embodiment, a sensor system for use in an extracorporeal body fluid sensing system comprises a fluidic device according to any of the embodiments described herein and a control unit configured to operate the fluidic device to flow a biocompatible cleaning fluid upstream from a cleaning fluid reservoir to an inlet of a sample flow path. The control unit may thus be configured to control the cleaning device and the collection valve, and may further control the operation of any further devices in or connected to the flow path, such as valves or pumping mechanisms.

[0035] Thus, the control unit configures the fluidic device to allow the biocompatible cleaning fluid to flow upstream from the cleaning fluid reservoir to the inlet of the sample flow path, e.g., operate any valves between the inlet and the cleaning fluid reservoir, which may also include closing other valves to prevent the cleaning fluid from traveling downstream and, e.g., mixing with any calibrant fluid in the sample flow path and sensor assembly.

[0036] The control unit may be implemented in any suitable manner, for example, using software and / or hardware, to perform the various required functions. This may include, for example, one or more microprocessors programmed using software (e.g., microcode) to perform the required functions. Examples of processor components that may be used in various embodiments include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs). In various implementations, the control unit may be associated with one or more non-transitory storage media, such as volatile and non-volatile computer memory, such as RAM, PROM, EPROM, and EEPROM. The non-transitory storage media may be encoded with one or more programs that, when executed on the one or more processors and / or controllers, perform the required functions. The various storage media may be fixed within the processor or controller, or may be removable, such that one or more programs stored thereon can be loaded into the control unit.

[0037] In one embodiment, a computer program including computer program code may be configured, when the computer program is executed on one or more physical computing devices, to cause the one or more physical computing devices to perform the methods or functions of the control unit disclosed herein. In one embodiment, one or more non-transitory computer-readable media have stored thereon a computer program, the computer program including computer program code configured, when the computer program is executed on one or more physical computing devices, to cause the one or more physical computing devices to perform the methods or functions of the control unit disclosed herein.

[0038] In one embodiment, the fluidic device further comprises a sensor assembly control valve disposed between the first junction and the sensor assembly interface, the sensor assembly control valve configured to selectively allow fluid flow along the sample flow path between the first junction and the sensor assembly interface. In such an embodiment, the control unit may be configured to close the sensor assembly control valve when operating the fluidic device to provide a biocompatible cleaning fluid to flow upstream from the cleaning fluid reservoir to the inlet of the sample flow path.

[0039] In certain embodiments, the control unit is configured to operate the sampling valve to provide bodily fluid through the inlet to the sensor assembly interface, and then the control unit is configured to operate the fluidic device to flow a biocompatible cleaning fluid upstream from the cleaning fluid reservoir to the inlet of the sample flow path, thereby clearing the bodily fluid from the sample flow path, which may be after the sampling valve is closed.

[0040] In one embodiment, the washing unit is operable to draw fluid from the sample flow path into the washing fluid reservoir, and the control unit is configured to operate the fluidic device to draw fluid from the sample flow path into the washing fluid reservoir.

[0041] In one embodiment, the system further includes a calibration fluid unit including a calibration fluid reservoir for receiving a calibration fluid, the calibration fluid reservoir fluidly connected to the sample flow path at the second junction and a calibration fluid delivery unit configured to provide the calibration fluid to the sample flow path, and a control unit configured to control delivery of the calibration fluid to a sensor assembly interface, which may be the sensor assembly if present. The control unit may be configured to prevent flow of the calibration fluid to the inlet and therefore control operation of any upstream valves (such as the sampling valve) to close at least one of these valves.

[0042] In one embodiment, the control unit is configured to operate the fluidic device to flow a biocompatible cleaning fluid from the cleaning fluid reservoir downstream through the sample flow path, which may be to the sensor assembly interface or to another outlet such as a waste reservoir. Cleaning in both directions cleans the valve in all positions, thereby further reducing the risk of contamination.

[0043] In one embodiment, a method of operating a fluidic device comprises: providing a fluidic device comprising: a sample flow path having an inlet and a sensor assembly interface downstream of the inlet, the inlet for receiving bodily fluid from a circulating fluid flow path and the sensor assembly interface for providing the bodily fluid to the sensor assembly; a sampling valve disposed along the sample flow path, the sampling valve configured to selectively allow fluid to flow along the sample flow path between the inlet and the sensor assembly interface; a washing unit for washing bodily fluid from at least a portion of the sample flow path, the washing unit comprising: a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; and a washing fluid delivery unit configured to provide the biocompatible washing fluid from the washing fluid reservoir to the sample flow path; flowing the body fluid from the inlet of the sample flow channel to the sensor assembly interface; and flushing the sample flow path to remove bodily fluids by flowing a biocompatible flushing fluid upstream from a flushing fluid reservoir to the inlet of the sample flow path.

[0044] In one embodiment, the fluidic device may be a fluidic device described according to any of the embodiments disclosed herein.

[0045] In one embodiment, prior to the step of flowing the bodily fluid from the inlet of the sample flow channel to the sensor assembly interface, the method further includes providing a biocompatible fluid to the sample flow channel and drawing the biocompatible fluid from the sample flow channel into a washing fluid reservoir, where the biocompatible fluid is used in a subsequent step of washing the sample flow channel to remove the bodily fluid. As described above, prior to use with a patient, extracorporeal bodily fluid sensing systems are typically filled with a biocompatible fluid, such as saline. This biocompatible fluid is also typically provided to a fluidic device of an associated sensing system. By providing a washing unit operable (or configured) to draw fluid from the sample flow channel, it is possible to draw the biocompatible fluid into a reservoir and then use this stored fluid in the washing process. This eliminates the need to store biocompatible fluid within the fluidic device itself prior to use, which can significantly increase manufacturing complexity and cost and potentially require regulatory approval for the fluidic device.

[0046] In one embodiment, the method further includes providing a sensor assembly fluidly connected to the sensor assembly interface of the sample flow path, and the step of flowing the bodily fluid from the inlet of the sample flow path to the sensor assembly interface further includes flowing the bodily fluid over the sensor assembly such that a property of the bodily fluid can be detected. The method may further include detecting a property of the bodily fluid, such as a concentration of one or more analytes (e.g., ions).

[0047] In one embodiment, the fluidic device further comprises a calibration fluid unit comprising a calibration fluid reservoir for receiving a calibration fluid, the calibration fluid reservoir fluidly connected to the sample flow path at the second junction and to a calibration fluid delivery unit configured to provide the calibration fluid to the sample flow path, and the method further comprises providing the calibration fluid to the sensor assembly interface, which may be before and / or after the measurement.

[0048] In one embodiment, washing the sample flow path to remove bodily fluids further includes flowing a biocompatible washing fluid downstream through the sample flow path from a washing fluid reservoir, which may be to a sensor assembly interface or to another outlet such as a waste reservoir.

[0049] 1 provides a schematic plan view of a fluidic device 101 for use in an extracorporeal body fluid system, the extracorporeal body fluid system comprising a circulating fluid flow path 105 in fluid communication with the fluidic device 101. Specifically, the extracorporeal body fluid system is for the treatment of a patient in which a body fluid BF, such as blood, is received from the patient into the circulating fluid flow path 105, treated or modified by the extracorporeal body fluid system, and then returned to the patient via the circulating fluid flow path 105. The fluidic device 101 is provided for collecting the body fluid BF from the circulating fluid flow path 105 and is used to determine at least one characteristic of the body fluid BF.

[0050] The fluidic device 101 includes an inlet 110a at one end of a sample flow path 110, the inlet 110a being fluidly connected to the circulating fluid flow path 105, and a sensor assembly interface 110b downstream of the inlet 110a. Thus, the inlet 110a can receive bodily fluid BF from the circulating fluid flow path 105, which can then flow along the sample flow path 110 to the sensor assembly interface 110b. In this embodiment, the fluidic device 101 further includes a sensor assembly 160 including multiple sensors 165 for detecting and measuring various analyte properties (e.g., concentrations). Examples include sensors 165 for detecting specific ion concentrations, conductivity, pH, and temperature. The sample flow path 110 passes through the sensor assembly 160 and has a series of holes (not shown) corresponding to each of the multiple sensors 165 so that fluid (such as bodily fluid BF) can contact the multiple sensors 165, thereby forming the sensor assembly interface 110b. In this embodiment, the sample flow path 110 leads to an outlet that communicates with a waste reservoir 170 where it is discharged.

[0051] The fluidic device 101 further comprises a collection valve 115 provided along the sample flow path 110, particularly disposed upstream of the sensor assembly interface 110b and adjacent to the inlet 110a, configured to selectively allow fluid, such as body fluid BF, from the circulating fluid flow path 105 to flow along the sample flow path 110 between the inlet 110a and the sensor assembly interface 110b.

[0052] The fluidic device 101 also includes a fluid delivery unit 120 for funneling bodily fluid BF from at least a portion of the sample flow path 110. The washing fluid delivery unit 120 includes a washing fluid reservoir 121 for receiving a biocompatible washing fluid FF, and a washing fluid delivery unit configured to provide the biocompatible washing fluid FF to the sample flow path 110. In this embodiment, the washing fluid delivery unit is an actuator (such as a pump) integrated with the washing fluid reservoir 121 (and therefore not depicted separately). The washing fluid delivery unit 120 is coupled to the sample flow path 110 at a first junction between the inlet 110a and the sensor assembly interface 110b, and includes a washing unit valve 125 disposed between the washing fluid reservoir 121 and the sample flow path 110, which selectively allows fluid flow between the washing fluid reservoir 121 and the sample flow path 110. The washing fluid delivery unit 120 , in particular the washing fluid delivery unit, is configured to provide a biocompatible washing fluid FF from a washing fluid reservoir 121 to the sample flow channel 110 .

[0053] 1 and the above description of the relative locations of the collection valve 115 and the washing fluid delivery unit 120 to the sample flow path 110, the fluidic device 101 is configured such that, during use, the washing fluid delivery unit 120 is operable to flow a biocompatible washing fluid FF upstream from the washing fluid reservoir 121 to the inlet 110a of the sample flow path 110. This is explained with reference to Figures 3A-3D.

[0054] The fluidic device 101 in this embodiment further comprises a calibration fluid unit 130 including a calibration fluid reservoir 131 for receiving a calibration fluid CF. The calibration fluid reservoir 131 is fluidly connected to the sample flow path 110 at a second junction, specifically between the collection valve 115 and the sensor assembly interface 110b, in this embodiment downstream of the first junction. In this embodiment, a sensor assembly control valve 135 is provided at the second junction and functions as a three-way valve to control the flow of the calibration fluid CF from the calibration fluid reservoir 131 to the sensor assembly interface 110b and thus to the sensor assembly 160, as well as the flow of fluid along the sample flow path 110 between the inlet 110a and the sensor assembly interface 110b. The calibration fluid unit 130 also comprises a calibration fluid delivery unit configured to provide the calibration fluid CF to the sample flow path 110. In this embodiment, the calibration fluid delivery unit is an actuator (such as a pump) that is integrated with the calibration fluid reservoir 131 (and therefore not depicted separately).

[0055] The calibration fluid CF is a fluid provided to ensure that the sensor 165 of the sensor assembly 160 is accurate and does not drift during use. When not performing measurements, the sensor 165 is typically immersed in the calibration fluid CF. Therefore, the calibration fluid CF also serves a cleaning function for the sensor assembly 160, but it is typically not a biocompatible fluid and therefore cannot re-enter the circulating fluid flow path 105. For example, the calibration fluid CF is typically a sensor assembly-specific fluid designed to have a specific concentration of analytes (e.g., ions) and is typically not approved by regulatory agencies for use within a patient. Such approval processes are cumbersome, country- or region-specific, and must be specific to each calibration fluid and may vary depending on the particular sensor array. Therefore, avoiding the need for approval is a significant advantage. The fluidic device 101 avoids this by using a cleaning fluid delivery unit 120, as described below, and by having a sensor assembly control valve 135 that can prevent fluid flow upstream from the calibration fluid reservoir 131.

[0056] Downstream of the sensor assembly interface 110b and the sensor assembly 160 is a waste reservoir 170 for receiving any waste fluid. Access to this is controlled by a waste valve 175 that selectively allows fluid to flow from the sample flow path 110 into the waste reservoir 170.

[0057] 2 provides a schematic plan view of a sensor system 100 for use in an extracorporeal body fluid system. The sensor system 100 comprises the fluidic device 101 of FIG. 1 in communication with a control unit 180 configured to operate the fluidic device 101. Specifically, the control unit 180 is configured to operate the fluidic device 101 to, among other possible operations, flow a biocompatible cleaning fluid FF upstream from a cleaning fluid reservoir 121 to the inlet 110a of the sample flow channel 110. This is through the operation of various valves and delivery units in the fluidic device 101 to provide this, as will be described in more detail below.

[0058] 3A-3D schematically depict the operation of the fluidic device 101 of FIG. 1 in one embodiment, which may be under the control of the control unit 180 as part of the sensor system 100 depicted in FIG. 2. That is, each of the operations may be controlled by the control unit 180.

[0059] 3A depicts the fluidic device 101 during sensing operation. In this configuration, the sample flow path 110 is opened from the inlet 110a to the sensor assembly 160, and the collection valve 115 and the sensor assembly control valve 135 are opened to allow bodily fluid BF to flow from the circulating fluid flow path 105 to the sensor assembly 160. This is typically under pressure caused by the flow of bodily fluid BF within the circulating fluid flow path 105. When the bodily fluid BF contacts the sensor 165 of the sensor assembly 160, the sensor system 100 can measure the properties of the bodily fluid BF. Although not depicted, the collection valve 115 and / or the sensor assembly control valve 135 can be closed during measurement, leaving the bodily fluid BF over the sensor 165. Alternatively, there can be a continuous flow of bodily fluid BF during this process.

[0060] 3B depicts the fluidic device 101 after a measurement operation and after undergoing a cleaning operation. In a first step, calibration fluid CF is delivered from calibration fluid reservoir 131 to the sample flow path 110 and downstream to sensor assembly 160 and ultimately to waste reservoir 170 (via waste valve 175, which may be open for at least part of this step). In this embodiment, sensor assembly control valve 135 prevents flow upstream of sensor assembly control valve 135 but allows calibration fluid CF from calibration fluid reservoir 131 to flow through and downstream of sensor assembly control valve 135. This process is used to clear these portions of the fluidic device 101 of bodily fluid BF and to recalibrate the sensors between measurements.

[0061] 3C depicts a further step of the cleaning operation, which may be performed simultaneously with or separately from (e.g., before or after) the step depicted in FIG. 3B. In this step, with the sensor assembly control valve 135 closed and the collection valve 115 open (for at least a portion of the process), the cleaning fluid delivery unit flows a biocompatible cleaning fluid FF from the cleaning fluid reservoir 121 upstream of the inlet 110a of the sample flow path 110 and through the inlet 110a into the circulating fluid flow path 105 of the extracorporeal system. This cleans the sample flow path 110 and all of the upstream portions of the mating valves, thereby reducing the buildup of components of the bodily fluid BF within these channels and on any components within this portion of the fluid flow path. For example, this allows the collection valve 115 to be cleaned, including any dead space within the upstream portion of the sample flow path 110 as well as the circulating fluid flow path 105 side of the collection valve 115 that would otherwise come into contact with the bodily fluid BF. As described above, this is particularly advantageous as it reduces failure or inaccuracies (e.g., due to contamination) of the fluidic device 101, for example, by reaching areas that cannot otherwise be cleaned by the calibration fluid CF. Because the flushing fluid FF is a biocompatible fluid, it can be returned to the circulation fluid flow path 105 and thus the patient without risking harm to the patient or significantly affecting the properties of the body fluid BF in a harmful manner.

[0062] 3D depicts a further cleaning step that may be performed in addition to or instead of the cleaning step depicted in FIG. 3B, in which the fluidic device 101 is configured to flow cleaning fluid FF downstream from cleaning fluid reservoir 121, through sensor assembly interface 110b and sensor assembly 160, and into waste reservoir 170. This allows the cleaning fluid FF to clean sensor assembly control valve 135 in the open position, thereby allowing the sensor assembly control valve 135, along with any associated dead space, to be fully cleaned. For example, this may clean any dead space between the first junction and the most upstream portion cleaned by the calibration fluid CF (i.e., downstream of the first junction but which may not be reached by the calibration fluid (i.e., upstream of the sensor assembly control valve 135 but not in the main flow of the cleaning fluid FF between the cleaning fluid reservoir 121 and the inlet 110a). Therefore, the cleaning unit valve 125 and the sensor assembly control valve 135 are open for at least part of this operation. The waste valve 175 may also be open for at least part of this. In this step, the collection valve 115 may be open or closed. It may, for example, be closed to encourage the cleaning fluid FF to flow to the waste reservoir 170.

[0063] 4A and 4B schematically depict further operations of the fluidic device 101 of FIG. 1 in one embodiment that may be under the control of the control unit 180 as part of the sensor system 100 depicted in FIG. 2. That is, each of the operations may be controlled by the control unit 180. The operations schematically depicted in FIGS. 4A and 4B may be performed in addition to, for example, before, the steps schematically depicted and described above in FIGS. 3A-3D.

[0064] 4A depicts the fluidic device 101 and associated circulating fluid flow path 105 of an extracorporeal body fluid system in an initial state, where no body fluid BF has been introduced into the circulating fluid flow path 105. Instead, the extracorporeal body fluid system, including the circulating fluid flow path 105, has been primed with a biocompatible fluid, such as saline, that can be used as a biocompatible flushing fluid FF. This is typically the case prior to use of the extracorporeal body fluid system. In this embodiment and the configuration depicted in FIG. 4A, the flushing fluid reservoir 121 is empty (i.e., has no biocompatible flushing fluid FF therein).

[0065] To provide the fluidic device 101 with a biocompatible washing fluid FF, the fluidic device 101 is operated to draw the biocompatible washing fluid FF into the washing fluid reservoir 121. Specifically, in this embodiment, prior to the step of flowing the body fluid BF through the circulation fluid channel 105 and the sample channel 110, the sampling valve 115 is opened, the washing fluid delivery unit 120 is operated to open the washing unit valve 125, and an actuator located in the washing fluid reservoir 121 draws the biocompatible fluid from the sample channel into the washing fluid reservoir. This causes the biocompatible fluid to become the biocompatible washing fluid FF. The fluidic device 101 can now be used in the manner described above, for example, as depicted in FIGS. 3A and 3B, so that the stored biocompatible washing fluid FF can be used in a subsequent step of washing the sample channel 110 to remove the body fluid BF.

[0066] Such embodiments are advantageous because they avoid the need to store biocompatible fluids within the fluidic device itself prior to use, which can significantly increase manufacturing complexity and cost and may require regulatory approval for the fluidic device.

[0067] As described above, operation of the fluidic device 101 in the manners schematically depicted in Figures 3A-3D, 4A and 4B may be under the control of the control unit 180. In particular, the control unit 180 may be configured to control the opening and closing of the collection valve 115, the sensor assembly control valve 135 and / or the waste valve 175, as well as the operation of the wash fluid delivery unit and the calibration fluid delivery unit.

[0068] 5 depicts an extracorporeal body fluid system 199 in use, with a patient connected to a circulating fluid flow path 105. Specifically, the circulating fluid flow path includes an inlet portion or line 105a and an outlet portion or line 105b, respectively, through which body fluid BF is extracted and returned. The fluidic device 101 may be contained within the extracorporeal body fluid system 199 or may be a separate component attached thereto. The fluidic device 101 may be attached to any portion of the circulating fluid flow path 105, including, for example, the inlet portion or line 105a or the outlet portion or line 105b.

[0069] In the embodiment, the fluidic device 101 and the control unit 180 are physically connected, however it is understood that any implementation of the control unit 180 is possible, which may be remote from the fluidic device 101 .

[0070] Figure 6 provides a schematic plan view of another embodiment of a fluidic device 201 for use in an extracorporeal body fluid system, which differs from the fluidic device 101 of Figure 1 in the order of components within the sample flow path. Like the embodiment of Figure 1, the fluidic device 201 connects to a circulating fluid flow path 105.

[0071] The fluidic device 201 includes an inlet 210a at one end of a sample flow path 210, the inlet 210a being in fluid communication with the circulating fluid flow path 105, and a sensor assembly interface 210b downstream of the inlet 210a. The fluidic device 201 further includes a sensor assembly 260 including a plurality of sensors 265 for detecting and measuring various analyte properties (e.g., concentrations). The sample flow path 210 has a series of holes (not shown) corresponding to each of the plurality of sensors 265 such that fluid (such as bodily fluid BF) may pass through the sensor assembly 260 and contact the plurality of sensors 265, thereby forming the sensor assembly interface 210b. In this embodiment, the sample flow path 210 continues to an outlet in communication with a waste reservoir 270, where the fluid can be discharged.

[0072] The fluidic device 201 further includes a collection valve 215 provided along the sample flow path 210 and positioned upstream of the sensor assembly interface 210b. In this embodiment, the collection valve is provided adjacent to the sensor assembly interface 210b. The collection valve 215 is configured to selectively allow fluid, such as bodily fluid BF from the circulating fluid flow path 105, to flow along the sample flow path 210 between the inlet 210a and the sensor assembly interface 210b.

[0073] The fluidic device 201 also comprises a fluid delivery unit 220 for channeling a body fluid BF from at least a portion of the sample flow channel 210. The washing fluid delivery unit 220 comprises a washing fluid reservoir 221 for receiving a biocompatible washing fluid FF, and a washing fluid delivery unit configured to provide the biocompatible washing fluid FF to the sample flow channel 210. In this embodiment, the washing fluid delivery unit is an actuator (such as a pump) integrated with the washing fluid reservoir 221 (and therefore not depicted separately).

[0074] The washing fluid delivery unit 220 is coupled to the sample flow path 210 at a first junction between the inlet 210a and the collection valve 215, such that the fluid delivery unit 220 couples to the sample flow path 210 upstream of the collection valve. A washing unit valve 225 is provided between the washing fluid reservoir 221 and the sample flow path 210, which selectively allows fluid flow between the washing fluid reservoir 221 and the sample flow path 210. Thus, the washing fluid delivery unit 220, and in particular the washing fluid delivery unit, is configured to provide a biocompatible washing fluid FF from the washing fluid reservoir 221 to the sample flow path 210.

[0075] The fluidic device 201 further comprises a calibration fluid unit 230 comprising a calibration fluid reservoir 231 for receiving a calibration fluid CF. The calibration fluid reservoir 231 is fluidly connected to the sample flow path 210 at a second junction, which in this embodiment is in the collection valve 215. In particular, the collection valve 215 is a three-way valve that also forms a valve for controlling the flow of fluid from the calibration fluid reservoir 231 to the sample flow path 210. The calibration fluid unit 230 also comprises a calibration fluid delivery unit configured to provide the calibration fluid CF to the sample flow path 210. In this embodiment, the calibration fluid delivery unit is an actuator (such as a pump) integrated with the calibration fluid reservoir 231 (and therefore not depicted separately).

[0076] Downstream of the sensor assembly interface 210b and the sensor assembly 260 is a waste reservoir 270 for receiving any waste fluids. Access to this is controlled by a waste valve 275 that selectively allows fluid to flow from the sample flow path 210 into the waste reservoir 270.

[0077] 1 in that the first junction is upstream of the collection valve 215. It should be understood that this device can be operated in the same manner as the fluidic device 101 of FIG. 1 as depicted in FIGS. 3A-3D, 4A, and 4B, although the sequence and configuration of the open and closed valves are different. The fluidic device of FIG. 6 may allow the upstream portion of the sample flow path 210 to be washed during measurement because the collection valve 215 does not need to be opened.

[0078] The fluidic devices disclosed herein, such as fluidic devices 101 and 201, can be used in sensor systems, such as sensor system 100, to monitor characteristics of a body fluid BF. They can be used to obtain multiple samples of body fluid BF at intervals over a period of time during a procedure or process performed by an associated extracorporeal body fluid system, such as system 199 depicted in FIG. 5. This can be an automated process under the control of a control unit, for example, at set and / or regular intervals, or it can be a manual process. These collection processes, which have downtime between measurements (e.g., 1-90 minutes, or more commonly 5-20 minutes), are particularly prone to clogging (e.g., blood clotting), and therefore the fluidic devices and cleaning processes described above are particularly suited to these systems. Cleaning can be performed after each measurement, such as by providing a calibration fluid to the sensor assembly.

[0079] For example, one exemplary use of the fluidic device is to: connecting the fluidic device to a circulatory fluid flow path of an extracorporeal body fluid system, the sensor assembly being in a dry state (as during storage); providing a calibration fluid to the sensor (transducer) of the sensor assembly (this step may include allowing the sensor to hydrate (e.g., for 1-30 minutes); sensor calibration may be performed at the end of this step); withdrawing bodily fluid from the circulation fluid flow path, providing the bodily fluid to a sensor assembly, and performing a measurement (which may be for 1 to 90 seconds, such as 30 seconds); and washing the body fluid from the sensor assembly using a wash fluid for at least the upstream wash step (described above) and, optionally, a calibration fluid for the downstream wash step or a wash fluid for the downstream wash step (described above). If a wash fluid is used for the downstream wash step, this step may further include providing the calibration fluid to a sensor (transducer) of the sensor assembly.

[0080] FIG. 7 schematically depicts a method of operation of a fluidic device according to an embodiment, the method comprising: providing a fluidic device 302, the fluidic device 302 comprising: a sample flow path having an inlet and a sensor assembly interface downstream of the inlet, the inlet for receiving the body fluid from the circulating fluid flow path and the sensor assembly interface for providing the body fluid to the sensor assembly; a sampling valve disposed along the sample flow path, the sampling valve configured to selectively allow fluid flow along the sample flow path between the inlet and the sensor assembly interface; a washing unit for washing body fluid from at least a portion of the sample flow path, a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; a washing fluid delivery unit configured to provide a biocompatible washing fluid from a washing fluid reservoir to the sample flow path; flowing the body fluid from the inlet of the sample flow channel 304 to the sensor assembly interface; and flushing the sample flow channel to remove bodily fluids by flowing a biocompatible flushing fluid 306 upstream from a flushing fluid reservoir to the inlet of the sample flow channel.

[0081] While exemplary embodiments of the devices, systems, and methods are shown, it should be understood that the detailed description and specific examples are for purposes of illustration only and are not intended to limit the scope. These and other features, aspects, and advantages of the devices, systems, and methods of the present invention can be better understood from the specification, appended claims, or aspects, and the accompanying drawings. It should be understood that the drawings are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar parts.

[0082] Other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the present disclosure, from an examination of the drawings, the disclosure, and the appended aspects or claims. In the aspects or claims, the word "comprising" does not exclude other elements or steps, and the singular does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent aspects or claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. 1. A fluidic device for use in an extracorporeal body fluid system having a circulating fluid flow path, comprising: a sample flow path including an inlet and a sensor assembly interface downstream of the inlet, the inlet receiving the bodily fluid from the circulating fluid flow path and the sensor assembly interface providing the bodily fluid to a sensor assembly; a sampling valve disposed along the sample flow path, the sampling valve configured to selectively allow fluid flow along the sample flow path between the inlet and the sensor assembly interface; a washing unit for washing the body fluid from at least a portion of the sample flow path; The cleaning unit comprises: a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; a washing fluid delivery unit configured to provide the biocompatible washing fluid from the washing fluid reservoir to the sample flow path; The fluidic device is configured such that, in use, the cleaning fluid delivery unit causes a biocompatible cleaning fluid to flow upstream from the cleaning fluid reservoir to the inlet of the sample flow path.

2. The fluidic device according to claim 1 , wherein the first junction is located downstream of the collection valve in the sample flow path.

3. a sensor assembly control valve disposed between the first junction and the sensor assembly interface; The fluidic device of claim 2 , wherein the sensor assembly control valve is configured to selectively allow fluid flow along the sample flow path between the first junction and the sensor assembly interface.

4. a calibration fluid unit comprising a calibration fluid reservoir for receiving a calibration fluid; 4. The fluidic device of claim 1, wherein the calibration fluid reservoir is fluidly connected to the sample flow path at a second junction and to a calibration fluid delivery unit configured to provide the calibration fluid to the sample flow path.

5. The fluidic device of claim 4 , wherein the first junction is upstream of the second junction.

6. 6. The fluidic device of claim 5, wherein a valve is located in the sample flow path between the first junction and the second junction to selectively allow fluid flow along the sample flow path.

7. 7. A fluidic device according to claim 1, wherein the washing unit is operable to draw fluid from the sample flow path into the washing fluid reservoir.

8. further comprising a sensor assembly; The fluidic device of claim 1 , wherein a sensor assembly interface of the sample flow path is in fluid communication with the sensor assembly.

9. 9. The fluidic device of claim 1, wherein, during use, the cleaning fluid delivery unit is further configured to flow a biocompatible cleaning fluid from the cleaning fluid reservoir downstream through the sample flow path.

10. 1. A sensor system for use in an extracorporeal body fluid system, comprising: A fluidic device according to any one of claims 1 to 9; a control unit configured to operate the fluidic device; The control unit is configured to operate the fluidic device to flow a biocompatible cleaning fluid upstream from the cleaning fluid reservoir to the inlet of the sample flow path.

11. the fluidic device further comprising a sensor assembly control valve disposed between the first junction and the sensor assembly interface, the sensor assembly control valve configured to selectively allow fluid flow along the sample flow path between the first junction and the sensor assembly interface; 11. The sensor system of claim 10, wherein the control unit is configured to close the sensor assembly control valve when operating the fluidic device to provide a biocompatible cleaning fluid to flow upstream from the cleaning fluid reservoir to the inlet of the sample flow path.

12. The control unit operating the sampling valve to provide bodily fluid through the inlet to the sensor assembly interface; 12. The sensor system of claim 10 or 11, wherein the fluidic device is then configured to operate to flow a biocompatible washing fluid upstream from the washing fluid reservoir to the inlet of the sample flow channel.

13. the wash unit is operable to draw fluid from the sample flow path into the wash fluid reservoir; The sensor system of claim 10 , wherein the washing unit is configured to operate the fluidic device to draw fluid from the sample flow path into the washing fluid reservoir.

14. a calibration fluid unit comprising a calibration fluid reservoir for receiving a calibration fluid; the calibration fluid reservoir is fluidly connected to the sample flow path at a second junction and to a calibration fluid delivery unit configured to provide the calibration fluid to the sample flow path; The sensor system of claim 10 , wherein the control unit is configured to control delivery of the calibration fluid to a sensor assembly interface.

15. 14. The sensor system of claim 10, wherein the control unit is configured to operate the fluidic device to flow a biocompatible cleaning fluid from the cleaning fluid reservoir downstream through a sample flow path.

16. 1. A method of operating a fluidic device, comprising: Providing a fluidic device, said fluidic device comprising: a sample flow path including an inlet and a sensor assembly interface downstream of the inlet, the inlet receiving the body fluid from the circulating fluid flow path and the sensor assembly interface providing the body fluid to a sensor assembly; a sampling valve disposed along the sample flow path, the sampling valve configured to selectively allow fluid flow along the sample flow path between the inlet and the sensor assembly interface; a washing unit for washing the body fluid from at least a portion of the sample flow path; The cleaning unit comprises: a washing fluid reservoir for receiving a biocompatible washing fluid, the washing fluid reservoir fluidly connected to the sample flow path at a first junction downstream of the inlet; a washing fluid delivery unit configured to provide the biocompatible washing fluid from the washing fluid reservoir to the sample flow path; flowing a bodily fluid from the sample flow path inlet to the sensor assembly interface; and washing the sample flow path to remove bodily fluids by flowing a biocompatible washing fluid upstream from the washing fluid reservoir to the inlet of the sample flow path.

17. providing a biocompatible fluid to the sample flow path prior to flowing the bodily fluid from the inlet of the sample flow path to the sensor assembly interface; drawing the biocompatible fluid from the sample flow path into the wash fluid reservoir; The method of claim 16 , wherein the biocompatible fluid is used to wash the sample flow path.

18. providing a sensor assembly fluidly connected to the sensor assembly interface of the sample flow path; 18. The method of claim 16 or 17, wherein the step of flowing a bodily fluid from the sample flow path inlet to the sensor assembly interface further comprises flowing the bodily fluid over the sensor assembly so that a property of the bodily fluid can be detected.

19. the fluidic device further comprises a calibration fluid unit comprising a calibration fluid reservoir for receiving a calibration fluid; the calibration fluid reservoir is fluidly connected to the sample flow path at a second junction and to a calibration fluid delivery unit configured to provide the calibration fluid to the sample flow path; 19. The method of any one of claims 16 to 18, wherein the method further comprises providing a calibration fluid to the sensor assembly interface.

20. 20. The method of any one of claims 16 to 19, wherein the step of washing the sample flow path further comprises flowing a biocompatible washing fluid downstream through the sample flow path from the washing fluid reservoir.

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