Method for disinfecting a fluid piping system of a medical device and medical device

Abstract

The disclosure relates to a method for disinfecting a fluid piping system (4; 104) of a medical device (2; 102). According to the disclosure, when defining a target profile for a fluid piping system temperature, a heating coefficient, which specifies a time-dependent increase in the fluid piping system temperature when the fluid piping system (4; 104) is heated, a passive cooling coefficient, which specifies a time-dependent decrease in the fluid piping system temperature when the fluid piping system (4; 104) is passively cooled, and a readiness time (t7) is specified, at which the fluid piping system temperature, after a final drop below a minimum disinfection temperature (T1), must be less than or equal to a maximum readiness temperature (T3), so that the device (2;102) is ready for use again after disinfection, and the cooling of the fluid piping system (4; 104) is carried out, at least temporarily, by passive cooling through simply stopping or interrupting the heating, before reaching a predetermined minimum value of the target lethality and before the minimum disinfection temperature is undershot for the last time. The disclosure further relates to a device (2; 102) configured to carry out a method according to the disclosure.

Description

Technical area

[0001] The present disclosure relates to a method for disinfecting (ie for reducing germs by a factor of at least 10 -5 ) of a fluid line system of a medical device according to the preamble of claim 1 and a medical device according to the preamble of claim 11. State of the art

[0002] In known disinfection devices, disinfection processes are time and temperature controlled or via an A0 value calculation.

[0003] In time- and temperature-controlled disinfection processes, a target disinfection temperature is set. Once the disinfection temperature is reached, a timer begins recording a holding and safety period. If the required disinfection temperature is maintained throughout the entire holding and safety period, disinfection is successful. A cooling phase then follows.

[0004] In disinfection processes with A0 value calculation, a target value for the A0 value is set. After a defined temperature is reached during the heating phase, the time and temperature values ​​are taken into account in the A0 value calculation. Once the A0 value is reached, the cooling phase begins.

[0005] The current methods are not energy-efficient because more energy is supplied to the system than is needed for disinfection. Temperature and time values, or the corresponding A0 value, are not taken into account during the cooling phase. Devices with active cooling do not evaluate the time at which a required target temperature must be reached, resulting in an increased demand for cooling water. Summary of Revelation

[0006] The object of the present invention is therefore to enable a disinfection of a fluid line system of a medical device which is more efficient with regard to the heat to be applied and / or the amount of disinfectant liquid to be used.

[0007] This object is achieved by a method having the features of claim 1 and by a medical device having the features of claim 11. Advantageous further developments are the subject of the subclaims.

[0008] A method according to the disclosure is designed to disinfect a fluid line system of a medical device, in particular a blood treatment device, preferably a dialysis machine, or a reverse osmosis system. "Disinfection" means, in particular, a germ reduction by a factor of between 10 and 15. -5 and exclusively 10 -6 to reach.

[0009] The procedure comprises the following steps: - Measuring a fluid line system temperature in a predetermined temperature measuring section within the fluid line system, in particular by means of at least one temperature sensor, preferably by means of several temperature sensors distributed over the fluid line system, wherein for monitoring and / or carrying out a disinfection, preferably a measured value of the temperature sensor that measures the lowest temperatures compared to the other temperature sensors can be used as the fluid line system temperature, and for monitoring and / or carrying out a cooling, preferably a measured value of the temperature sensor that measures the highest temperatures compared to the other temperature sensors is used as the fluid line system temperature, or wherein alternatively the measured values ​​of the temperature sensors can be averaged, for example, - Determining a target curve of the fluid line system temperature by means of a predetermined minimum value of a target lethality of germs potentially present in the temperature measuring section, wherein the target lethality is calculated by integrating the target curve of the fluid line system temperature over time from the first reaching of a minimum disinfection temperature, from which germs potentially present in the temperature measuring section can be killed, until the last time the temperature falls below the minimum disinfection temperature, - Heating the fluid line system by means of a disinfectant fluid in (time or heating time) sections of the target course of the fluid line system temperature, in which the fluid line system temperature is to be increased or kept constant, and - Cooling of the fluid line system in (time or cooling time) sections of the target curve of the fluid line system temperature in which the fluid line system temperature is to be reduced.

[0010] The actual lethality is calculated based on the target lethality. This means that the actual fluid line temperature is integrated over time from the first time the minimum disinfection temperature is reached until the last time the temperature falls below the minimum disinfection temperature. When calculating the target lethality and, accordingly, the actual lethality, time periods in which the measured fluid line temperature is below the minimum disinfection temperature are not taken into account or integrated.

[0011] According to the disclosure, a heating coefficient, a passive cooling coefficient and a readiness time are taken into account when determining the target profile of the fluid line system temperature.

[0012] The heating coefficient indicates a time-dependent increase in the fluid line system temperature during heating of the fluid line system. The passive cooling coefficient indicates a time-dependent decrease in the fluid line system temperature during passive cooling of the fluid line system. The operational readiness point is the point in time at which the fluid line system temperature must be less than or equal to a maximum operational readiness temperature after the last time the temperature fell below the minimum disinfection temperature, so that the device is operational again after disinfection.

[0013] According to the disclosure, before the predetermined minimum value of the target lethality is reached or before a value of the actual lethality corresponds to the predetermined minimum value of the target lethality and before the minimum disinfection temperature is last undershot, the cooling of the fluid line system takes place at least temporarily by means of passive cooling by simply stopping or interrupting the heating.

[0014] By also taking into account periods after heating has been stopped or interrupted when calculating the actual lethality, the operating time of a heater or heating device and the duration of a disinfection process can be shortened while maintaining the predetermined minimum value of the target lethality.

[0015] According to one aspect of the disclosure, the heating coefficient and / or the passive cooling coefficient can be determined by means of at least one test and / or a simulation before determining the target profile of the fluid line system temperature, in particular before or after measuring the fluid line system temperature in the predetermined temperature measuring section. The heating coefficient can be detected or determined based on measurement data, in particular during or at the beginning of the method during operation of a heater. The passive cooling coefficient can be detected or determined based on measurement data, in particular during or at the beginning of the method by temporarily switching off the heater. The heating coefficient and / or the passive cooling coefficient can be adjusted step by step, in particular by means of interconnected devices that analyze measurement data via cloud and / or edge computing.

[0016] If the heating coefficient and / or the passive cooling coefficient are determined before the target course of the fluid line system temperature is determined, heating and / or cooling phases can be advantageously taken into account during disinfection.

[0017] According to one aspect of the disclosure, the heating coefficient and / or the passive cooling coefficient can be monitored during implementation of the method, and if the heating coefficient and / or the passive cooling coefficient change, the step of determining the target profile of the fluid line system temperature can be performed repeatedly. In other words, the heating coefficient and / or the passive cooling coefficient can be recalculated based on measurement data during implementation of the method.

[0018] If the heating coefficient and / or the passive cooling coefficient are monitored and adjusted if necessary, the accuracy in calculating the actual lethality can be improved.

[0019] According to one aspect of the disclosure, when determining the target profile of the fluid line system temperature, an active cooling coefficient can be taken into account, which indicates a time-dependent decrease in the fluid line system temperature during active cooling of the fluid line system. Cooling of the fluid line system can be temporarily effected by means of active cooling by removing warm disinfectant fluid and / or supplying a coolant. The disinfectant fluid can, in particular, be mixed with chemicals. The coolant can, in particular, be of the type of fluid, for example, process water, that is used during regular operation of the medical device.

[0020] If an active cooling coefficient is taken into account when determining the target course, phases in which the fluid line system is actively cooled can be advantageously taken into account during disinfection.

[0021] According to one aspect of the disclosure, the active cooling coefficient can be determined by means of at least one test and / or a simulation before determining the target profile of the fluid line system temperature, in particular before or after measuring the fluid line system temperature in the predetermined temperature measuring section. The active cooling coefficient can be detected or determined based on measurement data, in particular during or at the beginning of the method, by temporarily switching off the heater and simultaneously discharging warm disinfection fluid and / or supplying a coolant.

[0022] If the heating coefficient is determined before the target course of the fluid line system temperature is determined, active cooling phases can be advantageously taken into account during disinfection.

[0023] According to one aspect of the disclosure, the active cooling coefficient can be monitored during implementation of the method, and if the active cooling coefficient changes, the step of determining the target profile of the fluid line system temperature can be performed repeatedly. In other words, the active cooling coefficient can be recalculated based on measurement data during implementation of the method.

[0024] If the active cooling coefficient is monitored and adjusted if necessary, the accuracy in setting the target progression with regard to reaching the operational readiness point can be improved.

[0025] According to one aspect of the disclosure, the predetermined target lethality, the operational readiness time, the passive cooling coefficient, and the active cooling coefficient can be used to calculate a last possible active cooling start time, after which the maximum operational readiness temperature can only be reached by active cooling and up to which the fluid line system is cooled exclusively by passive cooling. Passive cooling can, in particular, be achieved largely by natural convection.

[0026] According to one aspect of the disclosure, a safety factor can be taken into account when determining the predetermined minimum value of the target lethality.

[0027] If the predetermined minimum value of the target lethality is set higher than theoretically necessary, the probability of unintentionally inadequate disinfection can be reduced.

[0028] According to one aspect of the disclosure, the target profile of the fluid line system temperature can be set such that an average level of the fluid line system temperature between the first time the minimum disinfection temperature is reached and the last time the minimum disinfection temperature is undershot is above the minimum disinfection temperature.

[0029] Setting the average level of the fluid line system temperature above the minimum disinfection temperature can reduce the likelihood of inadvertently underheating.

[0030] According to one aspect of the disclosure, the average level of the fluid line system temperature between the first reaching of the minimum disinfection temperature and the last time the temperature falls below the minimum disinfection temperature can be lowered towards the minimum disinfection temperature if it is recognized that the fluid line system temperature can be lowered to the maximum operational readiness temperature without active cooling before the operational readiness time after the last time the temperature falls below the minimum disinfection temperature.

[0031] If the average level of the fluid line system temperature is lowered towards the minimum disinfection temperature as needed, the resource efficiency of disinfection can be increased.

[0032] The disclosure further relates to a medical device, in particular a blood treatment device, preferably a dialysis machine or a reverse osmosis system, comprising a fluid line system, at least one temperature sensor configured to measure a fluid line system temperature in a predetermined temperature measuring section within the fluid line system, an inlet for introducing a disinfectant fluid and / or a coolant into the fluid line system, an outlet for discharging the disinfectant fluid and / or the coolant from the fluid line system, a heating device for heating the disinfectant fluid, and a control device for controlling the inlet, the outlet, and the heating device depending on the fluid line system temperature measured by the at least one temperature sensor.

[0033] According to the disclosure, the control device is designed to execute a method according to the disclosure in response to a request. Brief description of the drawings

[0034] The present disclosure will be described in more detail below using preferred embodiments with reference to the accompanying drawings. Fig. 1 is a schematic view of a medical device according to the disclosure in accordance with a first embodiment; Fig. 2 is a schematic view of a medical device according to a second embodiment; Fig. 3 a schematic temperature-time diagram of a method according to the disclosure; Fig. 4 is a diagram showing the temperature and the A0 value over time during a method according to the disclosure until a predetermined minimum lethality value is reached; Fig. 5 one of the Fig. 4 corresponding diagram of a method according to the disclosure in which an increased predetermined minimum lethality value is achieved; and Fig. 6 diagrams showing the temperature, the A0 value and a system state of a medical device during a method according to the disclosure. Detailed description of preferred embodiments

[0035] Fig. Figure 1 shows a schematic view of a medical device 2 according to the disclosure, according to a first embodiment. The device is designed as a reverse osmosis system and has a fluid line system 4. The fluid line system 4 is equipped with a ring line 6, on which a temperature sensor 8 is provided. The temperature sensor 8 is designed to measure a fluid line system temperature according to the disclosure.Alternatively, several temperature sensors could be provided distributed across the fluid line system 4, wherein, for monitoring and / or performing a disinfection, a measured value from the temperature sensor that measures the lowest temperatures compared to the other temperature sensors is used as the fluid line system temperature, and for monitoring and / or performing a cooling, a measured value from the temperature sensor that measures the highest temperatures compared to the other temperature sensors is used as the fluid line system temperature. In addition, temperature sensors can be present in the medical device 2, in particular away from the fluid line system 4, which can be used in the same way for the calculation, in particular if it cannot be ruled out that the warmest or coldest point is located outside the fluid line system 4.

[0036] The device 2 has an inlet 10 through which a disinfectant fluid and / or cooling water can be introduced into the fluid line system 4 into the device 2.

[0037] The device 2 further comprises an outlet 12 through which disinfectant fluid and / or coolant can be discharged from the device 2.

[0038] The device 2 is equipped with a heating device 14 which is designed to warm up or heat disinfectant fluid located in the device 2 or in the fluid line system 4.

[0039] The device 2 has a control device 16 which is designed to be able to control the inlet 10, the outlet 12 and / or the heating device 14 in parallel or in series.

[0040] To disinfect the device 2 or the fluid line system 4, process water is introduced via the inlet 10 and heated in the device 2 by the heating device 14. The heated water is distributed as disinfectant fluid in the fluid line system 4 or in the ring line 6. To pump fluid in the device 2 or in the fluid line system 4, the device 2 can have a pump (not shown).

[0041] The disinfection is controlled by the control device 16 by calculating a lethality of germs potentially present in the fluid line system 4 or in the ring line 6.

[0042] The A0 value is used as an indicator for lethality, which is calculated according to ISO 15883 using the following formula: A0=∑10[T(t)−80°C]z⋅Δt "z" is the z-value, which can be defined, for example, in ISO 11139. For the A0 value, "z = 10°C" applies.

[0043] “T(t)” is the temperature of the disinfectant fluid in °C as a function of time “t”.

[0044] “Δt” is the selected time interval in seconds.

[0045] As soon as a predetermined minimum value of the A0 value has been reached, the device 2 or the control device 16 ends the thermal disinfection and switches to a cooling phase by directing warm water from the outlet 12 and replacing it with colder process inlet water.

[0046] Fig. Figure 2 shows a schematic view of a medical device 102 according to a second embodiment. The device 102 according to the second embodiment differs from the device 2 according to the first embodiment in that in the latter, the heating device 14 is integrally formed, whereas a heating device 114 according to the second embodiment is formed separately from a reverse osmosis device 118. The heating device 114 is connected to the reverse osmosis device 118 via a cooling fluid line 120 and a warming fluid line 122.

[0047] Fluid can be conducted from the reverse osmosis device 118 to the heating device 114 via the cooling fluid line 120. Fluid can be conducted from the heating device 114 to the reverse osmosis device 118 via the warm fluid line 122. The cooling fluid line 120 and the warm fluid line 122 are connected to each other via a return line 124, which branches off laterally from a section of the cooling fluid line 120 and branches laterally into a section of the warm fluid line 122. An overflow valve 126 is provided in the return line 124. A switching valve 128 is provided in the warm fluid line 122 upstream of the branching point of the return line 124.

[0048] Corresponding to the device 2 according to the first embodiment, the device 102 according to the second embodiment has a fluid line system 104 with a ring line 106. The ring line 106 is provided with a temperature sensor 108 in order to be able to measure the fluid line system temperature of a fluid located in the fluid line system 104 or in the ring line 106. Alternatively, several temperature sensors distributed over the fluid line system 104 could be provided, wherein for monitoring and / or carrying out a disinfection, a measured value from the temperature sensor that measures the lowest temperatures compared to the other temperature sensors is used as the fluid line system temperature, and for monitoring and / or carrying out a cooling, a measured value from the temperature sensor that measures the highest temperatures compared to the other temperature sensors is used as the fluid line system temperature.

[0049] The device 102 has an inlet 110 on the reverse osmosis device 118, via which a disinfection fluid and / or cooling water can be introduced into the fluid line system 104 in the device 102.

[0050] The device 102 further comprises an outlet 112 on the heating device 114, via which disinfectant fluid and / or coolant can be discharged from the device 102.

[0051] Like the integral heating device 14 according to the first embodiment, the separately formed heating device 114 according to the second embodiment is designed to be able to warm up or heat disinfection fluid located in the device 102 or in the fluid line system 104.

[0052] The device 102 has a control device 116 in the reverse osmosis device 118 and / or the heating device 114, which is designed to be able to control the inlet 110, the outlet 112 and / or the heating device 114 in parallel or in series.

[0053] During hot disinfection of the ring line 106 without hot disinfection of the reverse osmosis device 118, the heating device 114 is switched on and the heated water is fed into the ring line 106. The switching valve 128 is closed to keep the warm water within the heating device 114 and the ring line 106. If the heating device 114 requires fresh water, the reverse osmosis device 118 supplies it. The excess water flows back into the reverse osmosis device 118 via the overflow valve 126 in the return line 124.

[0054] During a hot disinfection of the ring line 106 and the reverse osmosis device 118, the heating device 114 is switched on and the heated water is fed into the ring line 106. The switching valve 128 is opened to also feed the hot water into the reverse osmosis device 118. The overflow valve 126 is set so that a permeate from the reverse osmosis device 118 must flow through the heating device 114. "Permeate" is understood to mean, in particular, water that has been separated from components previously dissolved in the water by means of a semipermeable membrane of the reverse osmosis device 118. The permeate is particularly suitable for use without further treatment to produce a dialysis fluid.

[0055] The disinfection of the device 102 according to the second embodiment is also controlled by an A0 value calculation. This means that as soon as a predetermined minimum value of the A0 value is reached, the device 102 terminates the thermal disinfection and switches to the cooling phase by discharging warm water via outlet 112 and replacing it with colder process inlet water.

[0056] Fig. 3 shows a schematic temperature-time diagram of a method according to the disclosure for disinfecting the device 2 or 102 or a desired course of the fluid line system temperature.

[0057] At a time t0, the fluid line system 4 or 104, which has an ambient temperature T0 at the beginning of the disinfection process, is started to be heated by means of a disinfection fluid.

[0058] At a time t1, the fluid line temperature reaches a minimum disinfection temperature T1, from which germs in the fluid line system 4 or 104 are killed.

[0059] The fluid line temperature is further increased after time t1 until a maximum heating temperature T2 is reached at time t2.

[0060] From time t2, the fluid line temperature is kept constant at the value of the maximum heating temperature T2 until the heating device 14 or 114 is switched off at a time t3.

[0061] From time t3 onwards, the fluid line system 4 or 104 cools passively, i.e. without the intervention of a cooling device.

[0062] At a time t4, the A0 value, i.e. the Fig. 3 The hatched area between the target curve of the fluid line temperature and the isotherm of the minimum disinfection temperature T1 between t1 and t4 represents a value above which the fluid line system 4 or 104 can be considered disinfected. To account for any discrepancies during disinfection, the target curve of the fluid line temperature is set such that an A0 value reached at a time t5 when the minimum disinfection temperature T1 is last undershot (which corresponds to a predetermined minimum value of a target lethality according to the disclosure) is greater than the theoretically required A0 value (at time t4).

[0063] From time t5, the fluid line system 4 or 104 continues to cool passively before active cooling is switched on at time t6 (“switching on active cooling” means that warm disinfection fluid is discharged from the fluid line system 4 or 104 via the outlet 12 or 112 and cold process inlet water is admitted into the fluid line system 4 or 104 via the inlet 10 or 110).

[0064] Starting at time t6, the fluid line system 4 or 104 is actively cooled so that the fluid line system temperature reaches a maximum operational readiness temperature T3 at an operational readiness time t7. In this example, the maximum operational readiness temperature T3 is higher than the ambient temperature T0. Alternatively, the ambient temperature T0 can also be defined as the maximum operational readiness temperature T3.

[0065] The time period from time t0 up to and including time t2 is a heating phase P1. The time period from time t1 up to and including time t3 is a holding phase P2. The time period from time t3 up to and including time t4 is a passive cooling disinfection phase P3. The time period from time t4 up to and including time t5 is a safety phase P4. The time period from time t5 up to and including time t6 is a passive cooling phase P5. The time period from time t6 up to and including time t7 is an active cooling phase P6. The time period from time t1 up to and including time t5 is a disinfection phase P7.

[0066] The gradient of the target fluid line temperature curve in the heating phase P1 corresponds to a heating coefficient according to the disclosure. The gradient of the target fluid line temperature curve in the passive cooling disinfection phase P3, the safety phase P4, and the passive cooling phase P5 corresponds to a passive cooling coefficient according to the disclosure. The gradient of the target fluid line temperature curve in the active cooling phase P6 corresponds to an active cooling coefficient according to the disclosure.

[0067] Fig. Figure 4 shows a diagram in which the fluid line system temperature and the A0 value are shown over time during a method according to the disclosure until a predetermined minimum lethality value is reached. Fig. In the example shown in Figure 4, the starting or ambient temperature T0 is 25°C, the predetermined minimum value of the target lethality at time t5=4500s is 600, the heating coefficient is 2°C / min and the passive cooling coefficient is 6°C / h.

[0068] It can be seen that the active hot cleaning lasts only 25.04 minutes (1502.3 seconds) and then switches to standby mode. With the resulting temperature of 75.04°C and the assumed cooling, an A0 value of 600 is achieved. Fig. In the example shown in Figure 4, there is no holding phase. Fig. 5 shows one of the Fig. 4 shows a diagram of a method according to the invention in which an increased predetermined minimum lethality value is achieved. In order to Fig. 4, a higher maximum heating temperature T2 is provided to achieve the increased predetermined minimum lethality value 720 at time t5=5000s. Since the predetermined minimum lethality value 720 is reached at a later time than in the example shown in Fig. 4, the use of active cooling in the Fig. 5 shown example rather necessary.

[0069] Fig. 6 shows diagrams in which the fluid line system temperature, the lethality or the A0 value as well as a system state of a medical device 2 or 102 can be seen even after reaching the predetermined minimum value of the lethality.

[0070] As with the Fig. 4 and Fig. In the examples shown in Figure 5, no holding phases are provided. This means that as soon as the fluid line system temperature reaches the maximum heating temperature T2 or as soon as the target profile of the fluid line system temperature allows the disinfection target to be achieved, the heating device 14 or 114 is switched off in the examples shown.

[0071] The predetermined minimum lethality value is reached after approximately 25 minutes (i.e., t5 = 25 min). To ensure that the device 2 or 102 is ready for use at a predetermined time, the device is actively cooled from the latest possible time t6. Fig. The bottom diagram in Figure 6 shows the activation of device 2 or 102. That is, the bottom diagram shows whether the heating device 14 or 114, pumps, and valves of device 2 or 102 are switched off or not. Preferably, device 2 or 102 switches off all energy consumers (except the control unit) to save energy during passive cooling.

[0072] In a further advantageous embodiment, the pumps / valves can be switched on briefly during the passive disinfection / cooling process to circulate the water. This aims to ensure the most homogeneous temperature distribution possible in the system.

[0073] In the Fig.In the example shown in Figure 6, the device 2 or 102 only needs to be actively cooled from approximately 30°C to 25°C for 190 seconds before the time of readiness for use. By taking the time of readiness for use into account, significant water and / or energy savings are possible compared to known disinfection methods. List of reference symbols 2; 102 device 4; 104 Fluid line system 6; 106 ring line 8; 108 temperature sensor 10; 110 entrance 12;112 outlet 14; 114 heating device 16;116 Control device 118 Reverse osmosis system 120 Cooling fluid line 122 Warm fluid line 124 Return line 126 Overflow valve 128 switching valve t0 Time of start of heating phase t1 Time of start of the disinfection process t2 Time at which the maximum heating temperature is reached t3 Time of switching off a heating device t4 Time of reaching a theoretically sufficient predetermined minimum value of lethality t5 Time at which a minimum lethality value predetermined with a safety factor is reached t6 Time of switching on active cooling t7 Operational readiness time T0 starting or ambient temperature T1 minimum disinfection temperature T2 maximum heating temperature T3 maximum operational temperature P1 Heating phase P2 holding phase P3 Passive cooling disinfection phase P4 Safety phase P4 P5 Passive cooling phase P5 P6 Active cooling phase P7 Disinfection phase

Claims

[1] Method for disinfecting a fluid line system (4; 104) of a medical device (2; 102), in particular a blood treatment device, preferably a dialysis machine, or a reverse osmosis system, comprising the steps: - measuring a fluid line system temperature in a predetermined temperature measuring section within the fluid line system (4; 104), - Determining a target curve of the fluid line system temperature by means of a predetermined minimum value of a target lethality of germs potentially present in the temperature measuring section, wherein the target lethality is calculated by integrating the target curve of the fluid line system temperature over time from the first reaching of a minimum disinfection temperature (T1), from which germs potentially present in the temperature measuring section can be killed, until the last time the temperature falls below the minimum disinfection temperature, - heating the fluid line system (4; 104) by means of a disinfectant fluid in sections of the desired course of the fluid line system temperature in which the fluid line system temperature is to be increased or kept constant, and - cooling the fluid line system (4; 104) in sections of the desired course of the fluid line system temperature in which the fluid line system temperature is to be reduced, characterized by , that when determining the target profile of the fluid line system temperature, a heating coefficient which indicates a time-dependent increase in the fluid line system temperature during heating of the fluid line system (4; 104), a passive cooling coefficient which indicates a time-dependent decrease in the fluid line system temperature during passive cooling of the fluid line system (4; 104), and a readiness for use time (t7) at which the fluid line system temperature must be less than or equal to a maximum readiness for use temperature (T3) after the last time the temperature fell below the minimum disinfection temperature (T1), so that the device (2; 102) is ready for use again after disinfection, are taken into account, and that before reaching the predetermined minimum value of the target lethality and before the minimum disinfection temperature is last undershot, the cooling of the fluid line system (4; 104) takes place at least temporarily by means of passive cooling by simply stopping or interrupting the heating. [2] Method according to claim 1, characterized by that the heating coefficient and / or the passive cooling coefficient are / is determined by means of at least one test and / or by means of a simulation before determining the desired profile of the fluid line system temperature, in particular before or after measuring the fluid line system temperature in the predetermined temperature measuring section. [3] Method according to claim 1 or 2, characterized bythat the heating coefficient and / or the passive cooling coefficient are / is monitored during execution of the method and if the heating coefficient and / or the passive cooling coefficient changes, the step of setting the target profile of the fluid line system temperature is carried out repeatedly. [4] Method according to one of claims 1 to 3, characterized by that when determining the target profile of the fluid line system temperature, an active cooling coefficient which indicates a time-dependent drop in the fluid line system temperature during active cooling of the fluid line system (4; 104) is taken into account and the cooling of the fluid line system (4; 104) takes place temporarily by means of the active cooling by discharging warm disinfection fluid and / or supplying a coolant. [5] Method according to claim 4, characterized bythat the active cooling coefficient is determined by means of at least one test and / or by means of a simulation before determining the desired profile of the fluid line system temperature, in particular before or after measuring the fluid line system temperature in the predetermined temperature measuring section. [6] Method according to claim 4 or 5, characterized by that the active cooling coefficient is monitored during execution of the method and if the active cooling coefficient changes, the step of setting the target course of the fluid line system temperature is carried out repeatedly. [7] Method according to one of claims 4 to 6, characterized bythat by means of the predetermined target lethality, the operational readiness time (t7), the passive cooling coefficient and the active cooling coefficient, a last possible active cooling start time (t6) is calculated, after which the maximum operational readiness temperature (T3) can only be reached by means of active cooling and up to which the fluid line system (4; 104) is cooled exclusively by means of passive cooling. [8] Method according to one of claims 1 to 7, characterized by that a safety factor is taken into account when determining the predetermined minimum value of the target lethality. [9] Method according to one of claims 1 to 8, characterized bythat the target course of the fluid line system temperature is set in such a way that an average level of the fluid line system temperature between the first reaching of the minimum disinfection temperature (T1) and the last falling below the minimum disinfection temperature (T1) is above the minimum disinfection temperature (T1). [10] Method according to claim 9, characterized by that the average level of the fluid line system temperature between the first reaching of the minimum disinfection temperature (T1) and the last time the minimum disinfection temperature (T1) is undershot is reduced in the direction of the minimum disinfection temperature if it is detected that the fluid line system temperature can be reduced to the maximum operational readiness temperature (T3) without active cooling before the operational readiness time (t7) after the last time the minimum disinfection temperature (T1) is undershot. [11] Medical device (2; 102), in particular a blood treatment device, preferably a dialysis machine, or a reverse osmosis system, with a fluid line system (4; 104), at least one temperature sensor (8; 108) which is designed to be able to measure a fluid line system temperature in a predetermined temperature measuring section within the fluid line system (4; 104), an inlet (10; 110) for introducing a disinfectant fluid and / or a coolant into the fluid line system (4; 104), an outlet (12; 112) for discharging the disinfectant fluid and / or the coolant from the fluid line system (4; 104), a heating device (14; 114) for heating the disinfectant fluid and a control device (16; 116) for controlling the inlet (10; 110), the outlet (12; 112) and the heating device (14; 114) as a function of the fluid line system temperature measured by the at least one temperature sensor (8; 108), characterized by , that the control device (16; 116) is designed to carry out a method according to one of claims 1 to 10 in response to a request.

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