Monitoring of intravenous drug administration

Abstract

The present invention relates to a method for controlling (S) an injection circuit (2) comprising at least two perfusion lines (4a-4d) and a junction (8) comprising the following steps: S1: for each solution, determination of a perfusion rate at the distal end (3) of the injection circuit (2); S2: determination of predefined properties of each solution; S3: determination of a configuration of the injection circuit (2); S4: calculation, from the perfusion rate of each solution, the predefined properties of each solution, and the configuration of the injection circuit (2), of a pressure to be applied as a function of time at the proximal end of each perfusion line (4a-4d); and S5: injection of each solution into the perfusion line (4a-4d) corresponding to the pressure calculated as a function of time in step S4. Figure for the abstract: Fig. 1

Description

Title of the invention: Control of intravenous drug administration FIELD OF THE INVENTION

[0001] The invention relates generally to the control of the administration of drugs by intravenous route, in particular in a multi-channel circuit. The invention finds particular application in the administration of drugs in neonatology. STATE OF THE ART

[0002] The administration of drugs intravenously is currently carried out using injection circuits. These injection circuits comprise a distal end connected to a catheter fixed to the patient, a proximal end at which there are one or more injectors which may comprise a syringe pump, a peristaltic pump or even a gravity infusion bag, each configured to administer a solution at a flow rate predetermined by the practitioner, and infusion lines (comprising tubes, ramps, filters, etc.) fluidically connecting the proximal end and the distal end of the injection circuit. However, when the patient is a newborn, particularly a premature baby, the prescribed infusion rate and the diameter of the catheters used are generally very low (of the order of 0.3 mL / h to 30 mL / h and a diameter generally less than 5 French).

[0003] However, it appears that the perfusion circuits currently used are the same for adults and newborns. They are therefore not suitable for low perfusion flow rates or the diameters of the catheters used in neonatology. The consequence is that not all of the solution(s) injected into the injection circuit reach the newborn in the time required by the practitioner. This is all the more true when the injection circuit comprises several perfusion lines in parallel which join at one or more junctions.

[0004] The Applicant has thus demonstrated by experiments and simulations that, in a conventional injection circuit comprising four one-meter-long perfusion lines, a solution could take two hours to reach the patient. However, such a delay can be critical for the patient's health. Statement of the invention

[0005] An aim of the invention is to remedy the aforementioned drawbacks by proposing a solution making it possible to make perfusions more reliable, particularly in newborns, and to ensure that solutions are administered to patients at the infusion rate predetermined by the practitioner.

[0006] Optionally, another objective of the invention is to be able to determine the time necessary for the injected solution(s) to reach the patient, in particular in the case of a newborn, regardless of the point of injection of the solutions in the injection circuit.

[0007] Optionally, another objective of the invention is to propose an injection system which is precise and robust in the event of disturbances in the injection circuit.

[0008] To this end, according to a first aspect of the invention, a method for controlling an injection circuit is proposed, the injection circuit comprising: - a distal end configured to be connected to a patient; - at least two infusion lines, each infusion line being connected at a proximal end to an injector configured to inject a solution into the corresponding infusion line; and - at least one junction fluidically connected upstream to the two perfusion lines and downstream to the distal end; the control method comprising the following steps: SI: for each solution, determination of an infusion rate at the distal end of the injection circuit; S2: determination of predefined properties of each solution; S3: determination of an injection circuit configuration; S4: calculation, from the infusion rate of each solution, the predefined properties of each solution and the configuration of the injection circuit, of a pressure to be applied as a function of time at the proximal end of each infusion line; and S5: injection of each solution into the corresponding perfusion line at the pressure calculated as a function of time in step S4.

[0009] Some preferred but non-limiting features of the control method according to the first aspect are the following, taken individually or in combination: - step S2 comprises the determination of at least one of the following predefined properties, for each solution: viscosity, density, temperature; - the injection circuit further comprises at least one of the following components: a tube, a filter, a tap ramp, a tap, a valve, an extension, a catheter, and step S3 comprises the determination of physical parameters of each component and of each junction, the physical parameters possibly comprising at least one of the following parameters: a length of the tube, a diameter of the tube, a type of junction, a type of filter, a height of the component or of the junction; - step S3 further comprises determining the position in the injection circuit of each component and each junction; - the method further comprises a step of modeling the injection circuit into a graph comprising nodes connected by edges, each edge being characterized by physical parameters of one or more components of the injection circuit and each node corresponding to a position of these components in the injection circuit, the control method further comprising the determination of the pressure losses introduced by all or part of the nodes and edges; - the pressure calculated in step S4 is further determined based on the pressure losses thus determined; - the method further comprises determining, at all or part of the nodes and edges, the pressure and / or flow rate as a function of time and the pressure losses thus determined; - during step S4, the pressure to be applied as a function of time to each injector is further calculated as a function of the pressure at the distal end of the injection circuit, said pressure possibly being equal to a predefined standard pressure; - when one of the pressures calculated in step S4 is lower than a minimum pressure of the corresponding infusion line or higher than a maximum pressure of the injection circuit, respectively, the pressure applied in this infusion line in step S5 is equal to the minimum pressure or the maximum pressure, respectively; - the method further comprises measuring a flow rate at the proximal end in the injection circuit and estimating an error as a function of the measured flow rate, the pressure calculated in step S4 being further determined as a function of the estimated error; - the method further comprises determining a concentration of all or part of the solutions downstream of the injection point, for example at the distal end; - the method further comprises a step of injecting an additional solution into the injection circuit and determining the concentration of the additional solution downstream of the injection point, for example at the distal end; and / or - the method further comprises determining the time required for the additional solution to reach the distal end of the injection circuit.

[0010] According to a second aspect, the invention proposes an injection system comprising: - an injection circuit comprising: - a distal end configured to be connected to a patient; - at least two infusion lines; and - at least one junction fluidically connected upstream to the two perfusion lines and downstream to the distal end; - at least two injectors, each injector being configured to inject a solution into a corresponding infusion line; and - at least one controller configured to calculate, from an infusion rate as a function of time for each solution at the distal end of the injection circuit, predefined properties of each solution and a configuration of the injection circuit, a pressure to be applied as a function of time to each injector, and to adapt the pressure applied by the injector at the proximal end of each infusion line so that said pressure is substantially equal to the pressure calculated by the controller.

[0011] Some preferred but non-limiting features of the injection system according to the second aspect are the following, taken individually or in combination: - the injection system further comprises a flow meter, preferably a volume flow meter, configured to measure a flow rate at a point in the injection circuit, the at least one controller being further configured to estimate an error as a function of the flow rate measured by the flow meter and correct the pressure to be applied as a function of the estimated error; - the injection system comprises a volume flow meter per infusion line, each flow meter being placed near an associated injector in order to measure the volume flow rate of the solution injected by the injector at the inlet of the corresponding infusion line; - the at least one controller is further configured to detect an anomaly in the injection circuit from the volume flow rate measured by the flow meter; - at least one controller is in sliding mode; and / or - all or part of the injectors comprise an actuator and a pressure sensor configured to measure a pressure at a proximal end of the corresponding infusion line and transmit information relating to the measured pressure to the at least one controller, the at least one controller being configured to adapt the pressure applied by each injector according to the information relating to the measured pressure.

[0012] According to a third aspect, the invention proposes a computer program product characterized in that it comprises code instructions for the execution of a method for controlling an injection circuit according to the first aspect.

[0013] According to a fourth aspect, the invention proposes a storage means readable by computer equipment on which a computer program product comprises code instructions for the execution of a method for controlling an injection circuit according to the first aspect. DESCRIPTION OF FIGURES

[0014] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0015] [Fig.l] schematically illustrates an example of an injection system according to an embodiment of the invention;

[0016] [Fig.2] illustrates an example of a representative model of the injection circuit of [Fig.l];

[0017] [Fig.3a] illustrates a first example of embodiment of the control and injection part in the first perfusion line of an injection system according to the invention;

[0018] [Fig.3b] illustrates a second example of embodiment of the control and injection part in the first perfusion line of an injection system according to the invention; and

[0019] [Fig.4] a flowchart of steps of a control method according to an embodiment of the invention.

[0020] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0021] An injection system 1 comprises an injection circuit 2 comprising, in a manner known per se, a distal end 3 configured to be connected to a patient and one or more perfusion lines 4a-4d.

[0022] The distal end 3 of the injection circuit 2 can be connected to the patient, for example, via a catheter 9.

[0023] An injection circuit 2 may comprise several infusion lines 4a-4d in parallel. Each infusion line 4a-4d is then connected proximally to a dedicated injector 5a-5d. The injectors 5a-5d are configured to inject a given solution into the infusion line 4a-4d at an infusion rate predefined by a practitioner. The infusion lines 4a-4d comprise, by way of non-limiting example, tubes 6, tap ramps, filters 7, valves, junctions 8, the catheter 9 which is connected to the patient, etc. These different elements being conventional they will not be detailed further here.

[0024] By solution, we will understand here any fluid capable of being injected into an injection circuit 2.

[0025] The perfusion lines 4a-4d join in the distal part at a junction 8, where the different solutions are mixed before being injected into the patient via the catheter 9. The junction 8 is a valve connected upstream to at least two perfusion lines 4a-4d and downstream to a tubing connected (directly or via of additional components) to the patient's catheter 9 allowing the solutions transported by the infusion lines 4a-4d to be mixed before flow to the tubing. If necessary, a junction 8 may include a mixer.

[0026] An example of injection circuit 2 has been illustrated in [Fig. 1]. This injection circuit 2 comprises four perfusion lines 4a-4d allowing four separate solutions to be injected: - a first perfusion line 4a connected in the proximal part to a first injector 5a and in the distal part to a first junction 8, here a T-valve 8, for the injection of a first solution; - a second perfusion line 4b connected in the proximal part to a second injector 5b for the injection of a second solution and in the distal part to the T-valve 8; - a filter 7 mounted between the T-valve 8 and the second junction 8, here a three-way extension 8, which is crossed by the fluid resulting from the mixture of the first and second solutions; - a third perfusion line 4c connected in the proximal part to a third injector 5c for the injection of a third solution and in the distal part to the three-way extension 8; - a fourth perfusion line 4d connected in the proximal part to a fourth injector 5d for the injection of a fourth solution and in the distal part to the three-way extension 8; and - a set of components connecting the three-way extension 8 to the patient, here two extensions and the catheter 9 connected to the patient, which receive the fluid obtained by mixing the four solutions.

[0027] Thus, the solution injected into the first perfusion line 4a passes successively through the T-valve 8, where it is mixed with the solution injected into the second perfusion line 4b, then the filter 7, the three-way extension 8, where it is mixed with the solutions injected into the third and fourth perfusion lines 4d, then the set of components downstream of the three-way extension 8 before reaching the patient.

[0028] In the following, the invention will be detailed in the case of an injection circuit 2 in accordance with [Fig.l]. This is of course not limiting and is simply intended to facilitate the description of the invention. Thus, the number of perfusion lines 4a-4d, junctions 8, filters 7, tubes 6, etc. their respective locations in the injection circuit 2 and the number of solutions injected are not limiting and can be adapted to the treatments to be administered to the patient and to the habits of the practitioner.

[0029] In order to make infusions more reliable, particularly in newborns, and to ensure that all prescribed solutions are administered to patients at the respective infusion rates predetermined by the practitioner, the invention proposes an injection system 1 and an associated control method S configured to control the injection pressure of the different solutions in the infusion lines 4a-4d taking into account the configuration of the injection circuit 2 and predefined properties of the different solutions. Where appropriate, a feedback loop can be implemented in order to take into account the differences between the flow rate in each infusion line 4a-4d resulting from the pressure applied by each injector 5a-5d and the flow rate actually measured in the injection circuit 2.

[0030] To this end, the invention proposes an injection system 1 comprising;

[0031] - the injection circuit 2, for example the injection circuit 2 described above in relation to [Fig.l];

[0032] - the at least one controller 10 configured to calculate, from an infusion rate as a function of the predefined time for each solution at the distal end 3 of the injection circuit 2, of predefined properties of each solution and of a configuration of the injection circuit 2, a pressure to be applied as a function of the time to each injector 5a-5d and to adapt the pressure applied by the injector 5a-5d at the proximal end of each perfusion line 4a-4d so that said pressure is substantially equal to the pressure calculated by the at least one controller 10.

[0033] The infusion rate corresponds to the infusion rate prescribed or decided by the practitioner. This is the flow rate of the solution at the distal end 3 of the injection circuit 2. The infusion rate therefore corresponds to the volume of solution to be administered to the patient during a given time interval and is expressed for example in mL / h. It should be noted that the solutions are not necessarily injected simultaneously. In this case, an initialization time (time from which the corresponding solution must be injected) must then also be entered.

[0034] The predefined properties for each solution that are taken into account in determining the pressure to be applied to each injector 5a-5d include the viscosity and density of each solution. If appropriate, the temperature of each solution may also be taken into account. Alternatively, a standard temperature value may be preselected for each solution.

[0035] The configuration of the injection circuit 2 corresponds to the description of the injection circuit 2 in order to allow the controller 10 to evaluate in particular the pressure losses introduced into the injection circuit 2. The configuration of the injection circuit 2 may include the type of components forming the injection circuit 2 (tubes 6, filters 7, junctions 8, ramps, taps, valves, extensions, connectors, etc.), the position in space and relative to the direction of flow of the solutions of each component in the injection circuit 2, and / or physical parameters of these components (length, diameter, height, type of filter 7 / junction 8 / valve, etc.).

[0036] From this information, the controller 10 can then calculate the pressure to be applied as a function of time at the proximal end of each perfusion line 4a-4d (step S4) and control the injector 5a-5d in order to inject each solution into the perfusion line 4a-4d corresponding to the pressure (as a function of time) thus calculated (step S5).

[0037] The controller 10 may for example comprise a memory in which the code instructions for executing the method for controlling the injection circuit 2 are stored, and a computer of the processor, microprocessor, microcontroller 10, etc. type, configured to execute these code instructions. The controller may for example comprise a computer configured to send the control parameters wirelessly, for example by Wi-Fi.

[0038] The data (infusion flow rates, predefined properties of the solutions, configuration of the injection circuit 2) can be entered by the practitioner by any suitable means, for example by a dedicated input interface of the controller 10. It will be noted here that the practitioner can directly enter the predefined properties in the input interface, or alternatively enter the solutions to be injected into the infusion lines 4a-4d and their respective concentrations, the controller 10 then deducing the predefined properties using a database listing the predefined properties for each recorded and matched solution (step SI).

[0039] Similarly, the practitioner can enter the configuration of the injection circuit 2 or choose from several typical configurations predefined by the controller 10 (i.e. configurations whose parameters are known) (step S2).

[0040] The calculation by the controller 10 of the pressure to be applied by each injector 5a-5d can for example be carried out as follows. The flows are considered here as laminar fluids. The numerical calculations can also be carried out under MATLAB.

[0041] Firstly, a representative model of the injection circuit 2 can be constructed so as to obtain a graph comprising nodes and edges connecting two by two of the nodes. Preferably, the edges are oriented according to the direction of flow of the fluids in the injection circuit 2. The nodes correspond to the variations in dimension in the injection circuit 2.

[0042] In practice, each edge is characterized by the physical parameters of one or more components (tube 6, filter 7, junction 8, catheter 9, etc.) of the injection circuit 2 and each node corresponds to the position of these components in the injection circuit 2. The different nodes are connected two by two by edges and are arranged relative to each other so as to correspond to the actual arrangement of the components of the injection circuit 2 (position in space and relative to the flow direction of the solutions of each component in the injection circuit 2). Each edge is associated with the predefined properties of the corresponding components 6, 7, 8, 9 (length, diameter, etc.). Each node can be associated, for example, with the height of the adjacent components 6, 7, 8, 9.

[0043] [Fig.2] illustrates an example of a representative model of the injection circuit 2 of [Fig.l] according to graph theory, examples of predefined properties (viscosity [p] and density [p]) and physical parameters (diameter [r], length [1]) of the circuit components having been indicated for each edge. If necessary, the height of each node can also be specified. It will be noted that here, the first solution is Smof-lipid (infusion rate: 0.3 mL / h), the second is nutrition liquid (infusion rate: 5 mL / h), the third solution is a 5% glucose solution (infusion rate: 0.4 mL / h) and the fourth solution is water (infusion rate: 10 mL / h for 1 h). In this model, nodes 1, 2, 4 and 5 correspond to the inputs of infusion lines 4a-4d, or roughly the first, second, third and fourth 5ds injectors, respectively.Node 3, which is positioned at the intersection of the edges connected to nodes 1 and 2, corresponds to the outlet of the T-valve 8. Element F corresponds to the filter 7 and is connected to node 3 (T-valve 8) via an edge corresponding to the tube 6 connecting the T-valve 8 and the filter 7 in the injection circuit 2. It will be noted that in this case, the properties of the filter 7 (type of filter 7, pore size, associated pressure drops, etc.) are associated with the edge extending between element F and node 6. Node 6 corresponds to the outlet of the three-way extension 8 connecting the filter 7, the third injector 5c and the fourth injector 5d. Nodes 7 to 10 correspond to the inputs and outputs of the components placed downstream of the three-way extension 8. Typically, node 10 corresponds to the output of the catheter 9 (and therefore to the patient).If necessary, the edges can be oriented in the model to define the direction of fluid flow in injection circuit 2 (from nodes 1 and 2 to nodes 3 and 6, from nodes 4 and 5 to node 6, and from node 6 to nodes 7, 8, 9 and 10).

[0044] From the information relating to the viscosity, the density and where appropriate the temperature of each solution, the controller 10 can calculate the volume flow rate, the density and the viscosity at any point of the injection circuit 2, that is to say at the level of each node and each edge of the injection circuit 2.

[0045] The volume flow rate and the density at any point in the injection circuit 2 and as a function of time can be calculated using continuity equations. For example, the volume flow rate of the fluid at node 3 is equal to the sum of the volume flow rate assigned to node 1 (i.e. the volume flow rate of the first solution) and the volume flow rate assigned to node 2 (i.e. the volume flow rate of the second solution). The density of the fluid at node 3 is equal to the sum of the density assigned to node 1 (i.e. the density of the first solution) and the density assigned to node 2 (i.e. the density of the second solution) according to the respective proportions of the mass flow rate of each solution.

[0046] The viscosity at any point in the injection circuit 2 can be determined conventionally, for example using the equations proposed by Wilke Jurgen, Kryk Holger, Hartmann Jutta, and Wagner Dieter, in “Visco Handbook”, edition 11 / 2015,2015.

[0047] From the density, the volumetric mass, the viscosity and the pressure losses at each point of the circuit, the controller 10 can then determine the pressure of the fluid at each point of the circuit, as a function of time. The pressure at each point of the circuit can for example be calculated using recursive functions starting from the node 10, the pressure of which is known (either because it is measured - pressure (arterial or venous) of the patient, or because a standard pressure is used - typically, 10 cm H2O (7.4 mmHg), 10 mm Hg or 13 cm H2O (10 mmHg)).

[0048] The pressure losses introduced by the fluid in the injection circuit 2 depend on the configuration of the injection circuit 2 and the viscosity of the fluid. They are calculated for each edge forming the injection circuit 2 and can take into account, if necessary, additional sources of pressure losses, such as pressure sensors possibly present in the injection circuit 2. Typically, the pressure losses resulting from the passage of the fluid in the tubes 6, catheters 9s, extensions, etc. and other tubing can be calculated using the unsteady Bernoulli equations. The pressure losses resulting from the passage of the fluid in the filters 7 or pressure sensors depend on the type of filter 7 or pressure sensor used and can be determined empirically and / or experimentally.The pressure losses resulting from the passage of fluid in the 8 junctions depend on the type of 8 junction used and can be calculated empirically (see for example the thesis of Vasava Paritosh, “Fluid Flow in T-Junctions of Pipes”, December 2007), experimentally and / or from the theory developed in the article by W. Blaisdell Fred and W. Manson Philip, “Loss of Energy at Sharp-Edged Pipe Junctions in Water Conveyance Systems”, 1963.

[0049] From the pressure determined at each point of the circuit, the controller 10 can then calculate the pressure to be applied as a function of time by each injector 5a-5d at the inlet of each perfusion line 4a-4d (i.e. at the nodes 1, 2, 4 and 5) so that the output flow rate (at the node 10) of each solution corresponds to the perfusion flow rate predefined by the practitioner. Each injector 5a-5d is then controlled by the controller 10 so as to inject the corresponding solution at a pressure equal to the pressure thus calculated. This pressure may vary over time depending on the infusion rate in the different infusion lines 4a-4d (the infusion rate may vary over time from one infusion line 4a-4d to another).

[0050] The pressure applied by each injector 5a-5d therefore defines the volume flow rate at which each solution is injected into the corresponding perfusion line 4a-4d.

[0051] Taking into account the configuration of the injection circuit 2 makes it possible, in addition to taking into account the pressure losses, to eliminate the zones of recirculation and blocking of the fluids at the junctions 8, in particular when the fluid coming from one of the branches of the junction 8 has a very low volume flow rate compared to the volume flow rate of the fluid coming from the other of the branches. Managing the supply of the perfusion lines 4a-4d by pressure, rather than by volume, in fact makes it possible to adjust the pressure applied by the injectors 5a-5d by taking into account the properties of the other injected solutions, regardless of when these other solutions are injected into the injection circuit 2, by modifying in real time the pressure applied by each injector 5a-5d at the inlet of each perfusion line 4a-4d.

[0052] Where appropriate, the injection system 1 further comprises a flow meter 12, for example a volume flow meter 12, configured to determine the volume flow rate of the fluid at a given point in the injection circuit 2. Preferably, a volume flow meter 12 is placed at the proximal end of each perfusion line 4a-4d, i.e. close to each injector 5a-5d.

[0053] The information relating to the volume flow rate measured by each flow meter 12 is then transmitted to the controller 10 in order to estimate an error between the setpoint (volume flow rate of each solution, which depends on the pressure applied by the injectors 5a-5d at the inlet of the perfusion lines 4a-4d) and the volume flow rate actually measured (step S6). The controller 10 then corrects the setpoint applied to the injectors 5a-5ds in real time by modifying the value of the pressure to be applied by each injector 5a-5d as a function of the error thus estimated.

[0054] The controller 10 may be of the PID regulator type (acronym for proportional, integral, derivative) or alternatively a sliding mode controller 10. A sliding mode controller 10, however, makes it possible to obtain more precise and more robust results, in particular during disturbances in the injection circuit 2 (point injection of a solution into the injection circuit 2, detection of leaks or occlusions). The discretized sliding mode further improves the robustness of the controller 10.

[0055] Optionally, the injection system 1 may further comprise a mass or volume flow meter configured to measure a flow rate between the last junction and the output of injection circuit 2 and thus check that the fluid actually administered to the patient corresponds to the practitioner's prescription, for each solution injected.

[0056] Preferably, the flow meters used are contactless.

[0057] For example, the injection system 1 may comprise the controller 10 connected, for each perfusion line 4a-4d, to an injector 5a-5d comprising an actuator 13 configured to inject the solution into the corresponding perfusion line 4a-4d and a device 11 for regulating the injection pressure of the actuator 13. The actuator 13 may for example comprise a motor, a compressor, a hydraulic pump. The device 11 for regulating the pressure may comprise a pressure regulator and a reservoir 14 ([Fig.3a]) containing the solution to be injected into the perfusion line 4a-4d (the pressure regulator 11 injecting pressurized air into the reservoir 14 in order to push the fluid into the perfusion line 4a-4d at a pressure equal to the setpoint sent by the controller 10), or a pressure sensor 11 mounted at the output of the actuator 13 ([Fig.3b]).When the injector 5a-5d comprises a pressure sensor 11, the latter is configured to measure a pressure at the proximal end of a corresponding infusion line 4a-4d and transmit a pressure value to the controller 10. The controller 10 then adjusts the setpoint of the actuator 13 in order to adapt the pressure applied by the actuator 11 at the proximal end of each infusion line 4a-4d so that it is substantially equal to the pressure calculated by the controller 10.

[0058] Where appropriate, the same actuator 13 may be common to several injectors 5a-5d.

[0059] The volume flow meters 12 are preferably mounted downstream of the corresponding tank 14 and connected to the controller 10 in order to allow, following the feedback loop described above, the error to be estimated and the setpoint sent by the controller 10 to the pressure regulators 11 to be corrected in real time.

[0060] The injection system 1 according to the invention is therefore faster and more precise since it takes into account the pressure at the inlet of the injection circuit 2 (which reflects possible disturbances downstream of the injectors 5a-5ds, such as fluid recirculations or blockages at the junctions 8, but also occlusions or leaks), in comparison with conventional systems (syringe pump type) whose injectors 5a-5ds are only controlled according to the flow rate to be injected. In particular, the time required for each solution to reach the desired infusion rate is reduced in comparison with the prior art, regardless of the viscosity, the volume injected and the infusion rate of the solution.

[0061] Furthermore, the control method S of the invention makes it possible to adjust the limit values ​​(in particular in pressure) triggering the alarms so that they correspond to the limits associated with the configuration of the injection circuit 2.

[0062] The presence of flow meters 12 and pressure sensors 11 in the injection circuit 2 also makes it possible to detect anomalies in the injection circuit 2, such as leaks or occlusions, more quickly. In particular, the injection system 1 may further comprise additional pressure sensors within the injection circuit (i.e. in addition to the sensors 11 at the output of the actuators 13) configured to measure the pressure in the injection circuit 2. When the pressure measured by these additional pressure sensors is lower than a threshold pressure (a sign, for example, of a leak or a network failure), the controller 10 may generate an alert (sending instructions to an audible and / or luminous alarm).

[0063] Furthermore, the flow meters and the pressure sensors (namely the pressure sensors 11 at the inlet of the perfusion lines 4a-4d and / or the additional pressure sensors placed within the injection circuit 2) allow, where appropriate, the controller 10 to estimate the predefined properties and the parameters resulting from the configuration of the injection circuit (diameter of the tubes, etc.) from the measured flow rate and pressure information. Where appropriate, the controller 10 can correct the calculated value of the pressure to be injected by the injectors 5a-5d on the basis of the pressure measured by the pressure sensors in the injection circuit 2.

[0064] Optionally, when one of the pressures calculated in step S4 in one of the edges is lower than a minimum pressure of the corresponding perfusion line 4a-4d, respectively, the pressure applied by the controller 5a-5d at the input of this perfusion line 4a-4d in step S5 is equal to the minimum pressure. The minimum pressure of a given perfusion line 4a-4d may for example correspond to the pressure necessary for a fluid to pass through the perfusion line 4a-4d, taking into account the pressure losses in the injection circuit 2.

[0065] Similarly, when one of the pressures calculated in step S4 is greater than a maximum pressure of the injection circuit 2, the pressure applied by the controller 5a-5d at the input of the corresponding perfusion line 4a-4d is equal to the maximum pressure. The maximum pressure of the injection circuit may for example correspond to the maximum pressure that can be applied so as not to damage the injection circuit or to the maximum pressure that can be supported by a patient.

[0066] The maximum pressure and the minimum pressure may be fixed parameters entered into the controller or alternatively be adapted according to the configuration of the injection circuit and / or the patient.

[0067] Optionally, the controller 10 can further determine the concentration of all or part of the solutions injected at any point of the injection circuit 2 as a function of time (step S7). The solution for which the evolution of the concentration is to be determined can be injected at any point of the injection circuit 2 (for example at level of node 3), or alternatively correspond to one of the solutions injected at points 1, 2, 4 or 5. Its initialization time can also be non-zero, i.e. the solution can start to be injected during processing, after the start of the injection of the other solutions in the injection circuit 2.

[0068] To monitor the evolution of the concentration of a given solution, the following information must be provided to the controller 10 (for example via the input interface):

[0069] - the initial concentration of the solution to be monitored (i.e. the solution from which wishes to determine the evolution of the concentration in the injection circuit 2);

[0070] - the duration of injection of the solution to follow;

[0071] - the infusion rate of the solution to follow (already entered to determine the pressure to be applied by the corresponding injectors 5a-5d when the solution corresponds to one of the first to fourth solutions); and

[0072] - its initialization time.

[0073] Preferably, the molecular diffusion coefficient (D) of the solution to be monitored is also entered or determined by the calculator from the matching database.

[0074] The controller 10 having determined the volume flow rate of the different fluids at any point of the injection circuit 2, it is then possible to deduce the evolution of the concentration over time at any point of the injection circuit 2, as well as the time necessary for each solution to reach the outlet of the injection circuit 2.

[0075] The evolution of the concentration as a function of time in a tube 6 (edge) of the circuit can in particular be determined by the controller 10 using the following differential equation (Taylor equation):

[0076] 3c(f) 7 j'Wçl (Rüt) \ cTch)

[0077] where: D corresponds to the molecular diffusion coefficient;

[0078] u corresponds to the axial velocity of the fluid through the tube 6;

[0079] x corresponds to the axial distance along the tube 6;

[0080] t corresponds to time;

[0081] R corresponds to the radius of the tube 6; and

[0082] c corresponds to a concentration of the solution.

[0083] It should also be noted that the horizontal bar on the parameters u and c means that these are average values.

[0084] Thus, the controller 10 can determine, using this differential equation, the evolution over time of the concentration of each solution at any point in the injection circuit 2, even during unsteady phases.

[0085] The controller 10 can then deduce the time required for each solution to reach the exit, i.e. the patient. This information can in particular be relevant for the practitioner in order to confirm that the planned assembly (configuration of injection circuit 2) is suitable for the patient and the prescribed infusion rates, or possibly adapt the initialization time of a given solution.

[0086] It will be noted that the injection of an additional solution into the injection circuit 2, in particular at a node downstream of the nodes 1, 2, 4 and 5, has the effect of modifying the concentration of the fluids in the injection circuit 2 as well as the flow rate at the outlet of the injection circuit 2. However, as soon as these variations are entered in the input interface, they are taken into account by the controller 10 which adapts the setpoint of the pressure regulators 11 and modifies the pressure applied by the injectors 5a-5ds in real time in order to guarantee that the flow rates always correspond to the infusion rates prescribed by the practitioner. When these variations are not entered in the input interface, they can however be taken into account by the controller 10 thanks to the feedback of information coming from the volume flow meters 12.

Claims

Claims

1. Injection system (1) comprising: - an injection circuit (2) comprising: - a distal end (3) configured to be connected to a patient; - at least two infusion lines (4a-4d), - at least one junction (8) fluidically connected upstream to the two infusion lines (4a-4d) and downstream to the distal end (3); - at least two injectors (5a-5d), each injector (5a-5d) being configured to inject a solution into a corresponding infusion line (4a-4d); and - at least one controller (10) configured to implement a control method comprising the following steps: S1: for each solution, determining the infusion rate as a function of time for each solution at the distal end (3) of the injection circuit (2); S2: determining the predefined properties of each solution; and S3: determining the configuration of the injection circuit (2);S4: calculation from the infusion rate of each solution, the predefined properties of each solution and the configuration of the injection circuit (2), of a pressure to be applied as a function of time at the proximal end of each infusion line (4a-4d) so that the infusion rate at the distal end (3) of the injection circuit corresponds to the infusion rate determined in step S1, so as to adapt the pressure applied by the injector (5a-5d) at the proximal end of each infusion line (4a-4d) so that said pressure is substantially equal to the pressure calculated by the controller (10).;

2. Injection system (1) according to claim 1, wherein step S2 comprises determining at least one of the following predefined properties, for each solution: viscosity, density, temperature.

3. Injection system (1) according to one of claims 1 and 2, wherein the injection circuit (2) further comprises at least one of the following components: a tube (6), a filter (7), a tap ramp, a tap, a valve, an extension, a catheter, and step S3 comprises determining physical parameters of each components and each junction (8), the physical parameters being able to include at least one of the following parameters: a length of the tube (6), a diameter of the tube (6), a type of junction (8), a type of filter (7), a height of the component or of the junction (8).

4. Injection system (1) according to claim 3, wherein step S3 further comprises determining the position in the injection circuit (2) of each component and each junction (8).

5. Injection system (1) according to one of claims 1 to 4, wherein the pressure to be applied as a function of time by each injector (5a-5d) is further calculated as a function of the pressure at the distal end (3) of the injection circuit (2), said pressure being able to be equal to a predefined standard pressure.

6. Injection system (1) according to one of claims 1 to 5, wherein, when one of the calculated pressures is lower than a minimum pressure of the corresponding infusion line (4a-4d) or higher than a maximum pressure of the injection circuit (2), respectively, the pressure applied by the injector (5a-5d) in this infusion line (4a-4d) is equal to the minimum pressure or the maximum pressure, respectively.

7. Injection system (1) according to one of claims 1 to 6, further comprising measuring a flow rate at the proximal end in the injection circuit (2) and estimating an error as a function of the measured flow rate (S7), the pressure calculated by the controller (10) being further determined as a function of the estimated error.

8. Injection system (1) according to one of claims 1 to 7, further comprising determining a concentration of all or part of the solutions downstream of the injection point, for example at the distal end (3).

9. Injection system (1) according to claim 8, further comprising a flow meter (12), preferably a volume flow meter (12), configured to measure a flow rate at a point in the injection circuit (2), the at least one controller (10) being further configured to estimate an error as a function of the flow rate measured by the flow meter (12) and correct the pressure to be applied as a function of the estimated error.

10. Injection system (1) according to claim 9, comprising a volume flow meter (12) per infusion line (4a-4d), each

11.

12.

13. flow meter (12) being placed near an associated injector (5a-5d) in order to measure the volume flow rate of the solution injected by the injector (5a-5d) at the inlet of the corresponding perfusion line (4a-4d). System according to one of claims 9 and 10, in which the at least one controller (10) is further configured to detect an anomaly in the injection circuit (2) from the volume flow rate measured by the flow meter (12). Injection system (1) according to one of claims 1 to 11, wherein the at least one controller (10) is in sliding mode. Injection system (1) according to one of claims 1 to 12, in which all or part of the injectors (5a-5d) comprise an actuator (13) and a pressure sensor (11) configured to measure a pressure at a proximal end of the corresponding perfusion line (4a-4d) and transmit information relating to the measured pressure to the at least one controller (10), the at least one controller being configured to adapt the pressure applied by each injector (5a-5d) as a function of the information relating to the measured pressure.

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