DE102012102850A1 - Fluid delivery device and fluid delivery method for medical applications - Google Patents

Abstract

The invention relates to a fluid delivery method and a fluid delivery device for medical use, having at least one fluid source (1) which is designed so that at least one fluid (4) can be discharged through it, at least one fluid sink (2) which is designed in such a way in that at least one fluid (4) can be accommodated by it, at least one fluid line (3) which is designed such that at least one fluid (4) can be conducted from the at least one fluid source (1) to the at least one fluid sink (2) at least one fluid flow influencing device (5), which is designed to influence the fluid flow (6) in the at least one fluid line (3), at least one sensor device (7), which is designed to at least one measured variable for describing a physical and or chemical property or state variable of the fluid, and an evaluation device (11) which is designed to be of a multiple number l of measured values of the measured variable to determine at least four values from which a sensor signal curve can be assigned to which at least one state can be assigned, wherein the at least one state is defined by at least one polynomial group, wherein the evaluation device (11) at least one polynomial from the polynomial cohort is determinable, and wherein the at least one polynomial describes the sensor signal waveform.

Description

The invention relates to a fluid delivery device for one or more medical applications. Furthermore, the invention is directed to a fluid delivery method for medical applications.

In general, fluid conveyors for medical applications have the requirement to be able to recognize safety-critical situations quickly and reliably while at the same time avoiding false alarms.

For this purpose, a value from a plurality of measured values of a measured variable is usually determined at a specific time, for. B. by applying a "moving average", and compared with a predetermined threshold. However, if, for example, an offset-laden or drifting measured variable whose offset or drift behavior is unknown or predictable, the selection of a suitable threshold value is usually difficult or even impossible. For example, a threshold value which is too close to the initial value quickly leads to false alarms, while a threshold value that is too far away from the initial value, for example, may impermissibly impair the sensitivity or the reaction time to critical situations.

Often safety critical situations are characterized by an increase (or decrease) of the measurand, which is significantly faster than that caused by a typical drift of the measurand. Then, two values from a plurality of measured values of a measured variable are typically determined at a specific time, eg. By applying a "moving average" (eg, at two different times), and the difference of the two values or the ratio of the difference of the two values to z. B. compared to their time interval with a threshold. This solves the described offset problem and significantly mitigates the drift problem (atypical drifts may still trigger false alarms). If a rapid recognition of an announcing safety-critical situation is to take place, the two values must not be far apart in time. However, then this procedure is not tolerant of short-term, not alarmist outliers. Non-alarmist outliers can z. B. caused by short-term disturbances, for example by environmental influences such as vibrations, which do not lead to a relevant safety-critical situation.

The shortcomings of the two standard methods described can be explained simply by the fact that no waveform (ie no higher derivatives) can reliably be derived from (maximum) two points, two values simply do not deserve the name sensor signal curve.

In practice, it is often the case that the user has to select the threshold value himself, directly or indirectly, human error is thus a frequent source of error. In addition, the user is generally deprived of the information about the reliability of the detection of a critical situation (as this can not be validly determined based on two values) - this complicates the appropriate response to e.g. B. the early prediction of the possible occurrence of a safety-critical situation.

The invention has for its object to provide a fluid delivery device that allows a meaningful evaluation current delivery conditions.

With the invention, a fluid conveying device is provided, as defined in claim 1, which allows this without the aforementioned disadvantages of known devices.

Furthermore, with the invention, a fluid delivery method is provided, as indicated in the independent method claim 14, which allows this without the aforementioned disadvantages of known methods.

Advantageous embodiments of the invention are specified in the subclaims.

In one embodiment of the invention, the evaluation device of the fluid delivery device is designed such that at least four values from the plurality of measured values of the measured variable can be determined by it. With the expression values, the individual measured values themselves or also, for example, from measuring sections or z. B. two or three or more individual measured values determined / certain / calculated values to be meant. In practice, the number of values may also include, for example, at least 10, at least 20 or more values. From these values, a sensor waveform can be determined, which is defined, for example, in terms of time, or in terms of space. At least one state such as "undisturbed conveyance", "lack of conveyance due to line blockage", "lack of fluid conveyance due to fluid reservoir depletion" or the like can be assigned to this sensor waveform. One such a state may be defined by a polynomial set comprising at least one, preferably a plurality of polynomials and optionally also may consist of several polynomial partial shares. By the evaluation can be determined from this polynomial a polynomial that describes the sensor waveform, ie if necessary. best approximated. On the affiliation of this polynomial to a respective polynomial crowd at the same time a currently existing, this polynomial character associated state recognized.

One, several or all polynomial crowds may each consist of polynomial partial shares, so that the same state can be described by, for example, differently extending polynomial partial shares.

The invention will be explained in more detail below with reference to embodiments with reference to the drawings.

1 shows an embodiment of a fluid delivery device according to the invention,

2 shows a more detailed block diagram of an in 1 shown exemplary sensor device and evaluation,

3 shows an exemplary course of a measured variable,

4 FIG. 3 illustrates an exemplary course of a sensor raw signal, FIG.

5 exemplifies the course of a sensor signal,

6 shows the exemplary course of a sensor signal with cyclic sampling,

7 shows an exemplary course of a possibly calibrated sensor signal,

8th FIG. 2 illustrates an exemplary course of a measured variable and an associated sensor signal course, FIG.

9 to 11 illustrate partial polynomial shares of the same exemplary state,

12 shows a superimposed representation of all the same exemplary state descriptive polynomial subgroups according to the 9 to 11 that all describe the same exemplary state

13 illustrates a polynomial subset for another example state,

14 shows a polynomial family for the same exemplary state as in FIG 13 .

15 illustrates an example of a sensor waveform and an approximation by a polynomial in a certain time interval, and

16 illustrates a superimposed representation of a sensor signal waveform, an associated approximation and of sets of states, ie states of defining polynomial clusters or polynomial subgroups.

In general, the measured variables to be measured can be, for example, a physical or chemical property or state variable. Alternatively, however, the measured variable may also be, for example, a variable via which it is indirectly possible to conclude a physical or chemical property or state variable that is actually to be monitored.

The present invention is preferably directed to a fluid delivery device, in particular for medical applications, wherein the fluid to be delivered can then be, for example, a therapeutic fluid or even a fluid, for example a contrast agent that is not intended for therapeutic or surgical treatment, but for example examination shots better statements and results possible.

In the following, some examples of a measured variable associated with a fluid to be delivered are described of a fluid conveying device according to the invention. The measured variable can be, for example, a pressure or a force, for example, a wall in contact with the fluid, a mass flow, a volume flow, a temperature, a density, a viscosity, concentration (for example of the fluid or fluid components) , the color of the fluid or of fluid components, electrical conductivity, compressibility, brightness, speed of sound in the fluid, heat capacity, the (relative) electrical permittivity, the (relative) magnetic permeability, the refractive index for example for an electromagnetic radiation such as light, resonances, e.g. , As nuclear magnetic resonance, luminescence, absorption behavior, reflection behavior, polarization behavior, for example when radiated electromagnetic radiation or sound and / or spectra of the fluid act. The measured variable may also relate to a property of a distribution of the aforementioned examples in the fluid, for example to the velocity distribution over the cross section of the fluid from which, for example, the volume flow can be determined. As a further example, the difference between the pressures of two points in a fluid line can also be used as the measured variable.

This in 1 illustrated embodiment of a fluid delivery device according to the invention has a fluid source 1 , a fluid flow influencing device 5 For example, in the form of a fluid delivery device such as a controllable pump, a sensor device 7 and a fluid sink 2 on. The components 1 . 5 . 7 and 2 are through fluid lines 3 connected in the manner shown. In another embodiment, the sensor device 7 also at the z. B. formed as a pressure source fluid source 1 arranged and z. B. be designed as a force sensor. The force sensor can, for. B. attached to a syringe pump drive arm. The sensor device 7 can z. B. as a pressure sensor on the hose wall of the fluid line 3 to be in the mood. With the reference number 4 is that in the fluid lines 3 referred to as flowing fluid. An arrow 6 denotes the fluid flow and indicates the flow direction within the fluid lines 3 at. As shown, the fluid flow influencing device 5 downstream of the fluid source 1 arranged. The sensor device 7 is in the embodiment according to 1 between the fluid flow influencing device 5 and the fluid sink 2 provided, but can also be arranged elsewhere, such that they are a measurement of the from the fluid source 1 exiting and towards the fluid sink 2 flowing fluid such as its pressure, flow rate, fluid quantity, etc. can sense.

With the sensor device 7 is an evaluation device 11 connected to that of the sensor device 7 generated, the measured measured variable such as the fluid flow reproducing, evaluating the sensor signal.

In 2 are the sensor device 7 and the evaluation device 11 presented in greater detail including their internal design and interconnection. The sensor device 7 has one or more sensors 9 on, the or a sensor signal in the form of a sensor raw signal ( 10 ) whose history and size is evaluated.

Furthermore, there is a filter 12 provided, which may for example be a noise filter, but also a noise filter 13 and / or a calibration filter 14 can be or contain. The filter 12 is preferably used as a noise, Störsignal- and calibration. In the presentation according to 2 is the filter 12 at the interface between the sensor device 7 and the evaluation device 11 arranged. The filter 12 However, it can also be completely in the sensor device 7 be included, or may also be part of the evaluation 11 be. Possibly. can also be both in or at the output of the sensor device 7 as well as in or at the entrance of the evaluation device 11 in each case a filter such as a noise filter, noise filter, calibration filter or the like may be provided, each of which sensor raw signal 10 or the sensor signal 15 filter.

The evaluation device 11 has an evaluation element such as a microprocessor or microcontroller 27 on, which evaluates the sensor waveform and for this purpose, if possible, one or more matching polynomial shares or polynomial shares and a the sensor signal waveform approximating polynomial determined from the set of polynomial shares or polynomial shares.

The processor 27 if necessary, an approximation device 22 have, for example, can be designed in the sense of a digital signal processor DSP, allows a very rapid, effective signal evaluation, and determines at least one polynomial as an approximation of a sensor signal waveform.

The one from the processor 27 or the approximation device 22 For example, generated results can be stored in a memory device 21 stored and / or in a display device 18 be displayed.

The following are examples of data acquisition by means of the sensor device 7 shown and here also a measurand 8th including its history explains, as in example 3 is shown.

At the in 3 shown exemplary time course of the measured variable 8th is plotted on the lower horizontal scale, ie the abscissa, the time axis, while the actual value, ie the current size of the measured quantity 8th on the vertical scale, ie the ordinate is plotted. The measured quantity 8th points at the in 3 illustrated example, the form of up to the time point "0" rising straight line, superimposed by a sinusoidal noise signal. From the time 0 occurs a drop in size up to about the time point "300" (these figures are, for example, a suitable time dimension of, for example, minutes, seconds or milliseconds or any other ordinal number such as sample number). After a slight overshoot, the measured value curve returns to the expected extrapolatoric value from the course up to the time 0 at about the time "600" and then continues to grow disproportionately in the short term. With such a course of the measured values, an estimation should be made, in particular in the time window between 0 and 300 or even further up to the time 600 or 800, as to whether the course of the measured variable is a safety-critical disturbance or other impairment and if measures in the sense of emergency actions or a Alarm should be taken.

In 3 is the time course of the measured variable 8th applied. In general, it must be the course of the measured variable 8th but not a temporal course. The measured quantity 8th can also be in the form of, for example, a spatial course, for example in the sense of a cross section through a fluid flow. In such an embodiment is then in the history representation according to 3 on the lower, horizontal axis, not the time, but plotted the location to illustrate a cross-section at a given time as an example.

The spatial course of a measured variable associated with the fluid in the fluid delivery device 8th For example, the flow profile may be z. B. on a parallel to the cross section of a fluid line section line. The flow profile can, for. B. in lines with circular cross-section, for example, as a parabolic profile.

The following are the sensor 9 and an example in 4 illustrated Sensorrohsignalverlauf 10 explained in more detail.

The in 4 illustrated time course of the sensor 9 the sensor device 7 measured raw values, hereinafter referred to as Sensorrohsignalverlauf 10 in general, differs from the actual course of the measured variable to be determined 8th who in 3 is shown by way of example. This may, for example, be due to the measurement technique or may be due to the fact that the measurement is influenced by random errors such as noise and / or systematic errors such as deviations due to production tolerances of the sensors, whereby the measurement results may be impaired or falsified.

As in 2 is shown, the sensor raw signal 10 through the filter 12 , for example in the form of a noise filter, are filtered such that the effects of disturbances such as signal noise are eliminated or at least reduced. This filtering then results in the 5 illustrated course of the (filtered) sensor signal 15 , The filter 12 such as the noise filter, as indicated, for example, part of the sensor device 7 be in the evaluation device 11 be provided at the interface between the sensor device 7 and the evaluation device 11 be provided or may be in a split form both in the sensor device 7 as well as in the evaluation device 11 and possibly also be arranged at the interface between these components. Alternatively or in addition to the filter (noise filter) 12 can the noise filter 13 and / or the calibration filter 14 be provided. According to 2 These three filter types can be combined into a common block. Alternatively, however, these filters can also be spatially separated, for example the noise filter 12 between the sensor 9 and the block 10 or following the block 15 be arranged. Likewise, the calibration filter 14 , if provided, before or after the blocks 10 . 12 , or 15 be arranged. This also applies to the position of the noise filter in a similar manner.

This in 2 illustrated, optionally provided noise filter 13 For example, the sensor raw signal 10 or one already through another filter such as the filter 12 or 14 filtered course of the sensor raw signal 10 filter such that effects of disturbances, such as known systematic disturbances, caused for example by a cyclic disturbance signal, can be reduced or eliminated. At the output of the filter stage, for example, the filters 12 . 13 and or 14 may then include the in 5 or 6 or 7 illustrated course of the sensor signal 15 , This sensor waveform 15 can be generated, for example, by filtering and / or sampling synchronous with the interference signal.

In 6 is the curve of the sensor signal with additional sampling, see the sampling points 15a represented.

A sampling synchronous with an interference signal can be effected, for example, by measuring the sensor only at the desired points in time (or in other embodiments, for example, location points or the like) or by passing the (possibly filtered) continuous sensor raw signal or sensor signal only with z , B. a fixed sampling frequency is sampled in synchronism with the noise signal and the samples are further processed, or alternatively only those measurements are taken into account, for example, the desired (time) points closest to or correspond to the concrete samples to the respective (time) points. In another embodiment, instead of the time points in the scan also z. B. act space points.

Furthermore, two or more sensors or sensor devices can also be used for scanning. Furthermore, the sampling does not necessarily have to be equidistant, but can also be carried out, for example, with variable time patterns or spatial patterns which change in a known time behavior.

In the case of an interference signal, for example due to the interference signal filter 13 is to be filtered out, it may be an interference signal that as such already to the time course of the measured variable 8th and may, for example, be represented by a cyclical variation in the volume flow caused by a delivery unit, such as an infusion pump of the fluid delivery device. Alternatively or additionally, such a disturbing signal can also be detected only by the scanning process or measuring process by the sensor device 7 caused, for example, by a 50 Hz noise.

The optional calibration filter 14 can the sensor raw signal 10 or also an already filtered sensor raw signal, a sensor signal 15 Filter such that, for example, a systematic offset is eliminated or reduced and / or the signal is scaled. In 7 is the course of a calibrated sensor signal 15 shown as an example. Here are only the filtered and calibrated measuring points 15a shown on the basis of which the further signal processing takes place.

8th illustrates a superposition of the history of the original measure 8th and the associated sensor waveform 15 passing through the sequence of sensor signal points 15a is represented.

In the following, an embodiment of a data processing will be explained in more detail.

In this example, the evaluation should 11 at a given time, for example, at time "800" on the time scale plotted on the abscissa, evaluate whether the sensor waveform 15 one of, for example, three predetermined states 18 ' . 25 . 26 can be assigned, and, if so, additionally determine which of the predetermined in Example 3 states 18 ' . 25 . 26 currently available. The evaluation device is designed to provide the result, for example in the memory 21 or visually on the display 18 , In each case, a section of the sensor signal profile is used for this evaluation 15 which comprises at least four values, but preferably contains at least 10 or at least 20 measured values.

The respective states are in this case preferably defined by at least one polynomial group (or by polynomial partial shares), as explained in the following example.

In the one or more states, it may be z. For example, a proper operation of the fluid delivery system, a faulty operation of the fluid delivery system or a failure of fluid delivery as examples. A condition may be, for example, a closure (occlusion) of the fluid conduit. Another condition may represent a partial closure of the fluid conduit. Another condition can do that Dry up the fluid source, for example, be empty by running infusion container. Another condition may represent a temporary dry up of the fluid source. Another condition may represent a leak in the system that is not detected as an interruption of fluid delivery, but as an undesirable pressure drop or reduced delivery at the outlet of the fluid delivery system (eg, cannula).

The state I discussed below as an example is in 12 with the reference number 18 ' represents the three polynomial parts 16 . 19 . 21 ' which in their turn belongs to the 9 . 10 and 11 are reproduced in isolation. Here is in the 9 to 11 each one of the three polynomial subgroups 16 . 19 . 21 ' shown, which represent the state I in their entirety. In the 9 to 11 In each case, a polynomial assigned to an approximation of a sensor waveform that has actually been determined is also shown, and with the reference numbers 17 . 20 . 22 ' designated. Each polynomial subset here comprises a plurality of polynomials, each of which lies in the polynomial subset, ie the corresponding "polynomial tube".

That is the polynomial crowd of state I 18 ' underlying polynomial has the polynomial degree N = 5:

Further, the parameter interval set defining the polynomial set consists of M = 3 parameter interval sets each having (2N + 1) = 11 parameter intervals, namely:
Parameter interval set 1 (corresponding partial polynomial 16: P ₁ ): α _-5,1 = α _-4,1 = α _-3,1 = α _-2,1 = α _-1,1 = 0 ∈ [0, 0] α _0,1 ∈ [3500, 3900] α _1,1 = -78,3 ∈ [-78.3, -78.3] α _2,1 ∈ [0.658, 0.6595] α _3,1 = -1.9 × 10 ^-3 [-1.9 × 10 ^-3 , -1.9 × 10 ^-3 ] α _4.1 = 2.3 · 10 ^-6 ∈ [2.3 · 10 ^-6 , 2.3 · 10 ^-6 ] α _5,1 = -10 ^-9 ∈ [-10 ^-9 , -10 ^-9 ] ⇒ P ₁ (t _p ) = α _0,1 - 78.3 · t _p + α _2,1 · t 2 / p - 1.9 · 10 ^-3 · t 3 / p + 2.3 · 10 ^-6 · t 4 / p - 10 ^-9 · t 5 / p

This means that z. For example, the following polynomial 17 belongs to the polynomial subset P ₁ : 3600 - 78.3 · t _p + 0.6585 · t 2 / p - 1.9 · 10 ^-3 · t 3 / p + 2.3 · 10 ^-6 · t 4 / p - 10 ^-9 · t 5 / p,

9 shows the partial polynomial P1 16 of state I 18 ' ,

In 10 is a parameter interval set 2 of the polynomial partial set P2 ( 19 ) and the polynomial 20 shown. In terms of formula, this is defined as follows: α _-5,2 = α _-4,2 = α _-3,2 = α _-2,2 = α _-1,2 = 0 ∈ [0, 0] α _0,2 ∈ [5500, 5800] α _1,2 = -78.3 ∈ [-78.3, -78.3] α _2,2 ∈ [0.651, 0.6515] α _3,2 = -1.9 × 10 ^-3 ∈ [-1.9 × 10 ^-3 , -1.9 × 10 ^-3 ] α _4,2 = 2.3 · 10 ^-6 ∈ [2.3 · 10 ^-6 , 2.3 · 10 ^-6 ] α _5,2 = -10 ^-9 ∈ [-10 ^-9 , -10 ^-9 ] P ₂ (t _p) = α _0.2 - 78.3 · t _p + α _2.2 × t 2 / p - 1.9 × 10 ^-3 · t 3 / p + 2.3 · 10 ^-6 · t 4 / p - 10 ^-9 · t 5 / p

This means that z. For example, the following polynomial 20 to the polynomial subset P ₂ belongs: 5700 - 78.3 · t _p + 0.6513 · t 2 / p - 1.9 · 10 ^-3 · t 3 / p + 2.3 · 10 ^-6 · t 4 / p - 10 ^-9 · t 5 / p

This is in 10 with the polynomial subset P ₂ , 19 , of state I, 18 ' represented.

11 illustrates a parameter interval set 3 for the polynomial subset P ₃ ( 21 ' ) of state I and the polynomial 22 ' , Where: α _-5,3 = α _4,3 = α _-3,3 = α _-2,3 = α _-1,3 = 0 ∈ [0, 0] α _0,3 ∈ [7000, 8000] α _1,3 = -78.3 [-78.3, -78.3] α _2,3 ∈ [0.66, 0.661] α _3,3 = -1.9 × 10 ^-3 ∈ [-1.9 × 10 ^-3 , -1.9 × 10 ^-3 ] α _4.3 = 2.3 · 10 ^-6 ∈ [2.3 · 10 ^-6 , 2.3 · 10 ^-6 ] α _5,3 = -10 ^-9 ∈ [-10 ^-9 , -10 ^-9 ] P ₃ (t _p ) = α _0.3 - 78.3 · t _p + α 2 · ₃ · t 2 / p - 1.9 · 10 ^-3 · t 3 / p + 2.3 · 10 ^-6 · t 4 / p - 10 ^-9 · t 5 / p

This means that z. For example, the following polynomial 22 ' to the polynomial subset P ₃ belongs: 7500 - 78.3 · t _p + 0.6605 · t 2 / p - 1.9 · 10 ^-3 · t 3 / p + 2.3 · 10 ^-6 · t 4 / p - 10 ^-9 · t 5 / p

This is in 11 with the polynomial subset P ₃ ( 21 ' ) of state I ( 18 ' ) graphically.

The state I with its three polynomial subgroups P ₁ , P ₂ and P ₃ can thus be as in 12 shown represent.

Analogous to the above statements on the state I and the polynomial partial groups representing them 16 . 19 . 21 ' In the following, another state II will be explained, which is represented by a single subset of polynomial, ie a polynomial crowd P4, which in 13 with the reference number 23 is illustrated. In this polynomial crowd 23 runs a determined, for example, by approximation of the sensor waveform polynomial 24 , The evaluation device 11 is thus able to recognize that the approximated sensor waveform 24 to the polynomial part 23 belongs, ie state II ( 25 ), for example a partial or complete occlusion.

In 14 is the polynomial crowd 25 which is representative of the state II and in this embodiment with the polynomial subset P4, 23 , is identical.

Hereinafter, the detection of Condition II will be described with reference to FIGS 13 . 14 described in more detail formulaically:
That the polynomial crowd of the state II ( 25 ) has the polynomial degree N = 2:

Further, the parameter interval set defining the polynomial set consists of M = 1 parameter interval sets with (2N + 1) = 5 parameter intervals, namely:
Parameter interval set 1 (associated polynomial part set ( 23 ): P ₄ ): α _-2,4 = α _-1,4 = α _1,4 = 0 ∈ [0, 0] α _0,4 ∈ [4000, 4300] α _2,4 ∈ [-0.006, -0.003] ⇒ P ₄ (t _p ) = α _0,4 + α _2,4 · t 2 / p

This means that z. For example, the following polynomial 24 belongs to the polynomial subset P ₄ : 4100 - 0.004 · t 2 / p

This is in 13 with the polynomial subset P4, 23 , state II, 25 , and 14 graphically illustrated.

In the illustrated embodiment, a state III ( 26 ) defined by the fact that the (approximated) sensor signal neither belongs to the state I nor to the state II, ie the approximated sensor signal curve does not form part of the polynomial subset 16 . 19 . 21 ' or 23 is. Such a state III can be treated as undefined, for example, so that, for example, an indication, for. B. "fault" can be output.

In the evaluation device 11 it is checked if a sensor waveform 15 a polynomial (or polynomial) and thus the state to which this polynomial group or polynomial group belongs. For this purpose, it is checked whether a polynomial of the polynomial group or partial polynomial considered exists that corresponds well to the sensor signal curve in the observation window (sliding window, with at least four measured values), ie the deviation between the relevant polynomial and the sensor signal course is sufficiently low is and does not exceed a predetermined limit. This limit can be fixed or, for example, proportional to the amplitude of the waveform, z. B. be set to 3% or 5% of the value of the signal waveform.

This polynomial is then approximated 27 ' the sensor waveform 15 designated and used for further processing.

If there are different polynomials for which this is the case, whose deviation from the sensor signal curve or the section just considered is equal to or smaller than the limit value, in an advantageous, optional embodiment that one of these different polynomials is selected for which the deviation from the sensor signal course is the lowest , This polynomial then becomes an approximation in this special case 27 ' the sensor waveform further processed.

In 15 is the sensor waveform 15 with the samples 15a and the approximation 27 ' graphically illustrated. Here, too, the time scale is plotted on the abscissa, while the values of the sensor signal or the approximation are plotted on the ordinate. According to 15 is the time range considered again the period from 0 to 800, the approximation 27 ' here sufficiently exactly the actual, by the values 15a illustrated course corresponds.

In 16 is a superimposition of the representations according to FIGS. 1 to 4 for the purpose of illustrating the polynomial subgroups, the sensor signal profile and the approximating polynomial 12 . 14 . 15 shown.

In the exemplary embodiment explained above, first the sensor signal profile and the polynomial which best approximates it can be determined, after which it is checked whether this approximating polynomial belongs to one or more of the polynomial groups or partial polynomial groups, and if so, to which polynomial group or polynomial component family.

In another embodiment, however, it is also possible to first check whether the sensor signal waveform belongs to one or more of the polynomial shares or partial polynomial shares, ie, lies "within" the "polynomial tubes" defined thereby. This can considerably reduce the processing outlay, in particular if the sensor signal course should not belong to one of the polynomial shares or partial polynomial shares. If it is detected that the sensor signal waveform does not lead to one of the polynomial shares or polynomial parts according to the respectively defined states, eg. State or state II, the further processing can be aborted. It is therefore with little effort and very quickly a meaningful result before that indicates, for example, that the current state of fluid delivery z. B. can not be estimated. The processing can then z. B., so that the processing cost is minimized, and it can be issued an error or fault message or even just a warning, z. B. visually by lighting a yellow warning lamp, for example.

Alternatively, it is possible to check whether there is an approximation in compliance with the boundary conditions specified by the parameter interval sets whose deviation is below a z. B. predetermined limit, for example, analogous to CurveFits with constraints. This can increase the processing speed in some cases, because the curve may converge faster.

On the other hand, if it is determined that there is a good conveying state (the sensor waveform is in one or more polynomial crowds associated with the "good" state), this may also be visualized, for example on a screen or by lighting a green lamp, for example. If a dangerous condition such as too little or a total lack of fluid delivery is detected, since the sensor waveform is, for example, in a polynomial group or polynomial group assigned to this hazardous condition, a different kind of warning can be given, for example by a red warning lamp lighting up and / or an audible warning is issued.

In a further embodiment, which may comprise all or any arbitrary part of the above-described features of the previously described embodiments, it is provided to check where the polynomial approximating the sensor signal waveform lies within the associated polynomial group or polynomial component group, i. H. which distance to the outer boundaries of the polynomial component family is maintained. If it is detected that the approximating polynomial lies, for example, directly in the middle of the associated "polynomial tube", this state is classified as very good or good and, for example, a corresponding statement stored and / or a green lamp, for example, lit up. On the other hand, if it is recognized that the approximating polynomial should be near or at the edges of the associated polynomial tubing, a warning may be issued that the system is operating close to its proper limit and there is a danger of leaving the associated polynomial tubing soon. This state can also be registered and visualized, for example, visually or acoustically by a yellow warning lamp, for example, or signaled by a corresponding acoustic or written indication.

The feedback on the reliability / quality / quality may alternatively or additionally be based on the deviation of the approximating polynomial from the sensor waveform.

In this embodiment, it is provided to detect what distance the polynomial approximating the sensor waveform from the boundaries of the associated polynomial or polynomial share, for example, a situation in which the approximating polynomial in the central region of, for example, 40% to 60% of polynomial hose width at the is classified as good. However, if the approximating polynomial is closer to the edge, for example, in the range of 20% to 40% or 60% to 80% of the current hose width, this condition is referred to as a "yellow" condition. If the approximating polynomial is in the range of 0% to 20% or 80% to 100% of the current polynomial width, d. H. Near or directly on the edge of the permissible polynomial crowd or polynomial partial family runs, this state can be classified as "dangerous" and given, for example, a corresponding acoustic, visual or visual indication.

The speed of the approximation of the approximating polynomial to the limits of the polynomial (partially) sharp can also be determined, and a warning about the soon-to-be leaving the desired functional range can be given early on at high speed.

In the embodiments described above, the fluid source 1 For example, correspond to an infusion container via an infusion tube as a fluid line 3 or fluid flow tube with a device or a patient as a fluid sink 2 can be connected. As a fluid flow influencing device 5 In this case, for example, a hose clamp for changing the cross section of the infusion tube and thus influencing the infusion flow can be provided. But it can also be used a syringe pump or the like. As a fluid flow influencing device 5 Alternatively or additionally, a peristaltic pump or an infusion pump may be provided, for example, which promotes the tube volume forward by means of peristaltic hose clamps.

For example, when using a syringe pump, a pump mechanism pushes a syringe plunger forward. In this example, the syringe pump and syringe together correspond to the fluid source 1 and the fluid flow influencing device 5 ,

In another embodiment, it is also possible to provide two or more fluid sources or fluid flow influencing means, which are then provided in common for an object to be treated or a patient. For example, two or more syringe pumps may be provided which are connected to a common tubing or fluid conduit 3 via check valves and two-, three- or multi-way valves are brought together. In this case, a filter may also be provided in the fluid flow path for mechanical filtering of the fluid streams. Alternatively, instead of a single, the fluid sink 2 , such as a patient, leading infusion line also be provided, for example, a 2-lumen catheter, which can lead into the bloodstream of the patient. Additionally or alternatively, a gravimetric delivery may be provided, in which one or more containers (bags) with infusion solution via infusion lines, for example with adjustable roller clamps and / or a peristaltic pump with, for example, a three-way valve tap to the fluid sink are merged, for example in the Carotid artery of a patient.

In another embodiment, as the fluid source 1 a bag may be provided, which may be part of a dialysis apparatus, which serves as a fluid flow influencing device 5 and may contain filters, etc. In such an embodiment, a waste container is additionally provided, and provided, for example, a 2-lumen catheter, which is inserted into the bloodstream of the patient. In this case, the fluid source 1 and the fluid sink 2 formed by the same object, wherein the bag can serve as a second fluid source. Such a design is effective for dialysis treatment. The sensor device 7 In this case, it may be provided on one or more of the hose lines leading to the patient and / or on the hose line leading away from the infusion bag and / or on the hose line leading to the waste container. Again, additional filters for z. B. be provided the extracorporeal blood treatment.

In another embodiment of the present invention, a diabetes implant is implemented in which an implant with a cartridge and a needle is provided in the patient. The cartridge may contain a diabetic agent, such as insulin, which is fed via the needle into the patient, which cartridge may also be designed as a metering pump, so that the injected diabetes mean and injection timings are selectively controllable. As a fluid source 1 here serves the cartridge with the diabetes agent, while as a fluid flow influencing device 5 the pump of the implant serves and the patient as a fluid sink 2 acts. In this case, the fluid flow between the outlet of the cartridge and the needle end by the sensor device 7 detected.

In a further embodiment of the fluid delivery device according to the invention and the fluid delivery method according to the invention, an intelligent, dynamic pressure monitoring is realized.

In this embodiment, the pressure of the fluid to be delivered in the infusion line is measured by measuring the force of the syringe plunger plate on the drive arm of a syringe pump or the force on a pressed onto the infusion line pressure sensor of a peristaltic pump or the like, is particularly advantageous to one to the drive unit of the pump synchronously operating filter used to determine the sensor waveform. In this case, the scaling / calibration of a parameter can be carried out particularly advantageously by the synchronous sampling / filtering, or at least greatly simplified thereby. The aim of pressure monitoring in this embodiment is to ensure a constant, steady, uniform and / or undisturbed delivery at the user-selected delivery rate.

The embodiment according to the invention can contribute to the fact that relative pressure changes can be detected and classified in terms of their significance, for example with regard to "good delivery rate", "critical delivery rate", "insufficient or excessive delivery rate", "uniform delivery", "non-uniform delivery", "Undisturbed promotion", "disturbed promotion", and the like. In any case, can be ensured by the pressure monitoring a steady fluid supply or deviations thereof are displayed.

Incorrect operations such as misorientation of a three-way stopcock or the like, forgotten or misplaced wire terminals or the like, twisted or bent wires or the like, or backward conveyance due to misplaced wires or the like come into consideration as failures of the system , These are errors that are visible from the outside. Hidden sources of error of the system can be blocked by filters or the like, through squeezed lumina, for example, in a catheter with multiple lumens, closed check valves or other weaknesses may be due.

Also at the syringe problems can be caused by blockages. For example, the syringe piston due to the friction between the piston seal and cylinder despite z. B. Feeding the syringe plunger stuck by a syringe pump (the feed then only leads to a deformation of the piston seal), so that no proper fluid delivery and, for example, no significant increase in pressure in the line before the syringe is achieved. Only when the piston seal breaks, it is possible in this accident, the syringe piston effectively push further inward and to achieve the infusion of the fluid.

Embodiments of the fluid delivery device according to the invention and the fluid delivery process according to the invention offer the advantages that they are compared to pressure offsets caused by, for example, height differences z. As the suspension of an infusion container or different syringe driving forces are tolerant. Furthermore, a measure of the quality of the fluid delivery and the reliability of their assessment is given, for example displayed and / or logged and / or presented in an acoustic form.

Furthermore, embodiments of the device according to the invention and of the method according to the invention are tolerant to disturbances such as movements of a patient or tube displacements, so that the number of false alarms is reduced. Furthermore, no manual intervention or adjustments, for example with regard to the entry of limit values, are required.

The embodiments of the fluid delivery device according to the invention and the corresponding method are also characterized by rapid response, for example, to critical disorders, since these can already be detected in their tendency, for example, before the fluid delivery is significantly disturbed. This is possible by ascertaining and evaluating the position of the polynomial approximating the current sensor signal profile in the associated polynomial tube (partial polynomial) and the magnitude of the deviation between polynomial and sensor signal course.

For example, the quality classes "excellent", "very good", "good", and "borderline" can be constructed, depending on the position of the approximating polynomial in the associated polynomial tube and the magnitude of the deviation between the polynomial and the sensor waveform. Thus, it is also possible to make some prediction as to whether the system conditions change in the direction of improvement or deterioration. In some embodiments, a pre-alarm can take place in the case of an imminent, but not yet occlusion. For example, in one or more embodiments, icons may be displayed on a display screen of the fluid delivery device of the present invention to indicate whether the device is off, idle, undergoing an initialization phase, or in normal operation. Furthermore, "normal" pressure fluctuations or even serious pressure fluctuations can be displayed on the display. Furthermore, it is possible to optically display predictions indicating, for example, that the device, i. H. the fluid delivery device will move in a correct range with correct baseline or will reach it shortly. Also, a prediction may be displayed that an occlusion is imminent or there is a line leak.

In embodiments of the fluid delivery device according to the invention and of the method according to the invention, a statistical approach for signal processing is used in which curve fits, splines, regressions or the like can be used moving averages ("sliding averages") or the like.

Embodiments of the fluid delivery device according to the invention and / or the method according to the invention can be used for automatic infusion.

The fluid need not be the same fluid throughout, but it is also possible, for example, to mix fluid from two fluid sources in one conduit. It is also within the scope of the present invention that the fluid source does not necessarily have to deliver fluid continuously, but may also have delivery-free intervals without fluid supply.

As a fluid sink, for example, a body or a living being considered, but also a collecting container. The fluid source may also be a living being, and it may be fluid source and Fluid sink z. B. also be directly connected to each other, so that a delivery cycle can be set.

The term "fluid flow" here includes all types of flow such as "laminar flow", "turbulent flow", "ideal flow", etc.

In general, embodiments of the present invention may include one or more active fluid delivery units, such as automatic pumps, or may also be configured as passive units, for example, in the form of roller clamps for manually changing the flow resistance through the hose. Further, it may be regulated components that are designed to keep the flow constant. Other embodiments of the device according to the invention and of the method according to the invention can also have uncontrolled components for the fluid delivery. For example, in embodiments of the present invention, the fluid flow influencing device can also only influence the flow profile with the volume flow kept constant. The generic term "flow" also means all terms such as flow profile and volume flow, just as it includes sets in which the delivery unit only consists of a constant, defined flow resistance such as a hose, a capillary, etc., so that the flow resistance possibly not at all changeable.

In embodiments of the invention, the sensor or the sensor device 7 may not necessarily be attached to or in the fluid line, but may for example also be positioned at the fluid source, at a syringe pump, etc.

By way of example, the term measured here also refers to the designation of a property which can be determined by measurement, statistical survey, sampling or execution of a random experiment. Furthermore, as a measured variable in the device according to the invention and the method according to the invention, for example also in embodiments, the force exerted by the fluid pressure on a syringe plunger, or the fluid pressure measured through the tube wall, means.

Although in the embodiments described above, the time course of the measured variable is treated, other embodiments may also be adapted to detect the spatial course of the measured variable, or the combination of the spatial course and the time course of the measured variable.

Embodiments of the fluid delivery device may be designed for medical and / or therapeutic use.

One or more embodiments of the invention thus have a fluid delivery device for medical use, the at least one fluid source for the delivery of at least one fluid, at least one fluid sink for receiving the at least one fluid, at least one fluid conduit for guiding the at least one fluid of the at least a fluid source to the at least one fluid sink, at least one fluid delivery unit or fluid flow influencing device for influencing the fluid flow in the at least one fluid line, at least one sensor unit for measuring at least one measured variable to describe a physical and / or chemical property or state variable of the fluid, and an evaluation device and optionally comprising a filter device. The evaluation device is designed to determine from a multiplicity of measured values at least four values, for example, but also more values of at least 10 or at least 20 values, from which a sensor signal curve can be determined. At least one state can be assigned to the sensor signal profile, wherein the at least one state is defined by at least one polynomial group. By means of the evaluation device, a polynomial can be determined from the at least one polynomial crowd. This polynomial describes the sensor waveform. By the respective polynomial crowd can be detected in a meaningful way, whether the polynomial describing the sensor waveform belongs to the respective polynomial crowd. If this is the case, it is hereby clearly established that the relevant state, such as, for example, occlusion, is present, so that, if necessary, countermeasures can be initiated very quickly or warnings can be generated.

The polynomial hereby preferably represents an approximation of the sensor signal curve. An approximation is considered to be given if the deviation between the approximating polynomial and the sensor signal curve lies below a predetermined limit value which is assigned to the respective state or to the polynomial partial group belonging to the state.

The deviation of the approximation may also advantageously be present in the form of a function of the sum of powers of the magnitudes of the differences between the values of the approximating polynomial and the corresponding values of the sensor signal curve.

If necessary, the evaluation device can also determine a plurality of polynomials and associate the sensor signal curve with that state in whose polynomial group the polynomial that has the smallest deviation from the sensor signal curve is contained.

In embodiments of the invention, the fluid source and / or the fluid sink and / or the fluid line can also be in several parts or interrupted.

Furthermore, a filter device may be provided, for example the filter device 12 . 13 and or 14 , which performs a synchronous to a noise signal sampling of the sensor waveform or the Sensorrohsignalverlaufs. Also, synchronous filtering may be performed in which noise filtering, noise filtering and / or calibration filtering is performed in synchronism with the sampling. As a result, the filtering effort can be significantly reduced if, for example, only a plurality of measured values and / or measured value ranges whose width z. B. may be significantly smaller than a period of the interference signal, z. B. 1% to 30% or 92% to 100% of this period, enter the filtering process, whereas the filtering may be exposed for the intermediate areas. In this case, the "values" are determined / determined / calculated from these measured values or measured value ranges.

In embodiments of the invention, the reliability of the association between the sensor waveform and the state is evaluated based on the deviation between the sensor waveform and the approximating polynomial. The evaluation result can be displayed to the user, so that a quality display is realized, from which the "good state" or the state of impending trouble or the like can be determined.

The fluid source may be, for example, an implant, a syringe, an infusion container, a medical cartridge or a living being or the like.

The fluid line may include as a part, for example, the source, a cannula, a catheter, an infusion line, a transfusion line, a tube, or the like.

The fluid may be, for. As an infusion solution, a nutritional solution, a drug, blood or other liquid act. The destination of the fluid can be as a fluid sink, for example, directly or indirectly a living being or a part of the living being, wherein the fluid may possibly also be intracorporeal be supplied.

In one, several or all embodiments, the sensor may be a force, pressure, mass flow, volumetric flow, temperature, density, viscosity, concentration, color, conductivity, compressibility, brightness, or spectroscopic sensor or the like. The quantities to be measured can be measured here indirectly or else directly depending on the exemplary embodiment.

In embodiments, the fluid delivery device can also be designed as a fluid delivery system in which the evaluation device can be part of an infusion pump, a dialysis machine, an insulin pump, an implant and / or an injection pen or can communicate with such a device.

In one or more embodiments, the fluid source and the destination, i. H. the fluid sink agree. In some embodiments, multiple fluid sources and / or fluid conduits and / or destinations, i. H. Fluid sinks be present.

In one or more exemplary embodiments, a plurality of identical, overlapping or different subsystems of fluid sources, fluid line and destination or fluid sink can be connected in series.

In some embodiments, the fluid delivery unit or fluid flow influencing device may also include the fluid source and / or the fluid conduit and / or the destination, i. H. include the fluid sink.

The force acting on the fluid can be generated or influenced by arranging and / or dimensioning the fluid source and / or the fluid line and / or the destination or the fluid sink.

The force acting on the fluid can also be generated or influenced, for example, by gravitational, temperature or pressure gradients between the fluid source and the fluid sink.

In some embodiments, the system components may perform different functions in different steps, and then their assignment to the terms fluid source, fluid line and / or fluid sink may change.

In some embodiments, the fluid source and / or fluid conduit and / or the fluid sink may spatially and / or functionally overlap.

In some embodiments, the fluid delivery device may be designed such that it is simultaneously determined whether multiple courses of different physical or chemical properties or state variables of the fluid each correspond to or approximate a predetermined course.

One or more embodiments may also be configured to determine from the course of the pressure in the system, i. H. in the fluid delivery device or in a part of the fluid delivery device in the case of one or more defined or known changes in the volume of the device or part of the device, for example compression or decompression, to the amount of fluid or part of the fluid, in particular a gas, present in the considered volume shut down.

As a result, statements about unintentionally or deliberately trapped air bubbles in the system can be made, for example. If it is detected that the amount of gas exceeds a predetermined limit, a suitable measure such as a vent can be performed. This fluid flow fluctuations, due to trapped air can be reduced or avoided.

For example, the ideal gas equation of state, the law of Boyle-Mariotte, the law of Gay-Lussac, or the law of Amontons may be consulted to record the amount of gas present in the considered volume. As a result, an air bubble detection and / or determination of the volume of an air bubble can be reliably achieved.

In exemplary embodiments of the invention, it may further be provided to determine the approximation (closest to the polynomial) associated with the sensor signal profile with the smallest deviation. However, if the sensor signal course can not be assigned a predetermined course in the sense of a polynomial crowd and thus the state is not detectable since the approximating polynomial is not attributable to a polynomial group, the fluid conveying device can be designed to take measures for a certain time, including a possible operator to encourage, force or force an action such as an emergency shutdown and emergency response to refrain. Thus, an alarm or other measure is not immediately taken in this case, but it is waited for a given time interval from the occurrence of this situation without action, whether the fluid delivery device automatically finds itself back into an assessable state. Only when this time interval expires without restoration of a known state, an action request, for example, in acoustic or optical form is subsequently issued and / or a device intervention such as a shutdown, a change of the delivery conditions or the like is performed.

Advantageously, there is at least one predetermined course of the sensor signal that corresponds to the proper state and / or operation of the fluid delivery device. Furthermore, there may also be at least one further predetermined course of the sensor signal, which corresponds to an improper state and / or operation of the fluid delivery device. The fluid delivery device may in this case preferably be designed such that it acoustically and / or optically signals the proper and / or improper state and / or operation of the fluid delivery device or makes the associated information accessible in another way, for example by appropriate storage and / or a log expression.

Alternatively or additionally, the fluid delivery device can also acoustically and / or optically signal the improper state and / or operation of the fluid delivery device or make the associated information accessible, for example by storage or a protocol expression and the like.

Embodiments of the fluid delivery device may be configured to output or provide information in addition to the above-mentioned signaling or the information about the proper or improper state and / or operation, the information relating to the validity, d. H. the validity of the acoustic and / or optical signaling or the associated information relates. This gives a user even an additional indication of the severity of a detected fault and / or the quality of the detected trouble-free operation of the device, etc.

The improper condition and / or operation of the fluid delivery device may be, for example, occlusion or partial occlusion of the fluid conduit, temporary or permanent depletion of the fluid source, and / or leakage in the system, i. H. in the fluid delivery device.

All the above-mentioned features can each represent the invention individually or in any mutual combination and can also be claimed in this form.

Within the scope of the invention, furthermore, there is a computer program product which contains codes, by means of which a processor for executing one, several or all steps of the above-explained method and / or the method according to one of the method claims can be initiated.

Claims (20)

Fluid delivery device for a medical application, comprising at least one fluid source ( 1 ) which is designed such that at least one fluid ( 4 ) can be dispensed, at least one fluid sink ( 2 ) which is designed such that at least one fluid ( 4 ) is receivable, at least one fluid line ( 3 ) which is designed such that at least one fluid ( 4 ) from the at least one fluid source ( 1 ) to the at least one fluid sink ( 2 ) is conductive, at least one fluid flow influencing device ( 5 ), which is adapted to the fluid flow ( 6 ) in the at least one fluid line ( 3 ), at least one sensor device ( 7 ), which is designed to contain at least one measurand ( 8th ) for the description of a physical and / or chemical property or state variable of the fluid, and an evaluation device ( 11 ), which is designed from a multiplicity of measured values of the measured variable ( 8th ) at least four values from which a sensor waveform ( 15 ), to which at least one state can be assigned, wherein the at least one state is defined by at least one polynomial crowd ( 28 ) is defined, wherein the evaluation device ( 11 ) is designed to contain at least one polynomial ( 27 ' ) from the polynomial crowd ( 28 ), the at least one polynomial ( 27 ' ) describes the sensor waveform. The fluid delivery apparatus of claim 1, wherein the polynomial set consists of M polynomial subsets, a subset of polynomial being defined by a (2N + 1) elementary set of open, half-open or closed parameter intervals, and the m-th polynomial subset of all N-th degree polynomials

whose parameter α _{k, m} , all in the respectively associated parameter interval] b _{k, m} , e _{k, m} [are. The fluid delivery device of claim 2, wherein the set of parameter intervals is substantially one (3 x M) elemental set {[0], [b _{0, m} , e _{0, m} ] and [b _{1, m} , e _{1 , m} ]} or their open or semi-open equivalents, or {[0],] - ∞, ∞ [and [b _{1, m} , e _{1, m} ]} or their open or semi-open equivalents. The fluid delivery device of claim 2, wherein the set of parameter intervals is substantially one (3 x M) elemental set {[b _{-1, m} , e _{-1, m} ], [b _{0, m} , e _{0, m} or their open or semi-open equivalents, or {[b _{-1, m} , e _{-1, m} ],] - ∞, ∞ [and [0]} or their open or semi-open equivalents. Fluid delivery device according to one of the preceding claims, wherein the at least one polynomial represents an approximation of the sensor signal waveform. Fluid delivery device according to claim 5, adapted to measure the deviation of the approximation, i. H. of the at least one polynomial to determine from the sensor waveform and to accept the at least one polynomial as an approximation only when the deviation is below a predetermined threshold, the threshold may be associated with or dependent on a respective state or polynomial constituent associated therewith , The fluid delivery apparatus of claim 6, adapted to determine the deviation of the approximation as a function or based on the sum of powers of the magnitudes of the differences between the values of the approximation and the corresponding values of the sensor waveform. Fluid delivery device according to one of the preceding claims, in which the evaluation device ( 11 ) is designed to determine a plurality of polynomials and assign the sensor waveform to the state in whose polynomial family that polynomial is included which has the least deviation from the sensor waveform. Fluid delivery device, in particular according to one of the preceding claims, which is adapted to synchronously scan the measured quantity ( 8th ) or a sensor raw signal ( 10 ) or the sensor waveform ( 15 ) and / or to perform a filtering of the Sensorrohsignals or a sensor signal waveform synchronous to an interference signal. Fluid delivery device according to one of the preceding claims, which is designed to evaluate the reliability of the association between the sensor waveform and the state and / or the quality of a condition and / or its detection based on a possibly existing deviation and notify the user, for example in Form of a message. A fluid delivery device according to any one of the preceding claims, having one or more or all of the following features: the fluid source is a syringe or infusion container; the fluid is an infusion solution, a nutritional solution, a drug or blood; the fluid sink is a living being or a part of a living being; The fluid can be delivered intracorporeally. Fluid delivery device according to one of the preceding claims, wherein the sensor device ( 7 ) comprises a force sensor or a pressure sensor and is optionally arranged on a piston rod, optionally a piston rod plate, a syringe or on the wall of an infusion line Fluid delivery device according to one of the preceding claims, in which the evaluation device ( 11 ) is formed as part of an infusion pump or is in communication with such. Fluid delivery method for medical use, wherein at least one fluid ( 4 ) of at least one fluid source ( 1 ) to at least one fluid sink ( 2 ) by at least one fluid line ( 3 ) is conductive, wherein the fluid flow ( 6 ) in the at least one fluid line ( 3 ) by a fluid flow influencing device ( 5 ) and at least one measured variable ( 8th ) for describing a physical and / or chemical property or state variable of the fluid by a sensor device ( 7 ), wherein a plurality of measured values of the measured variable ( 8th ) at least four values are determined from which a sensor signal course ( 15 ), to which at least one state is or is assigned, the state ( 18 ' ) by a polynomial crowd ( 28 ) and at least one polynomial ( 27 ' ) from the polynomial crowd ( 28 ), which describes the sensor waveform. The method of claim 14, wherein the polynomial group consists of M polynomial subgroups, where a polynomial subset is defined by a (2N + 1) elementary set of open, half-open or closed parameter intervals and the m-th polynomial subset of all Nth-order polynomials

whose parameters α _{k, m are} all in the respectively associated parameter interval] b _{k, m} , e _{k, m} [lie. Method according to Claim 14 or 15, in which a sampling of the measured variable synchronous with an interference signal ( 8th ) or a sensor raw signal ( 10 ) or the sensor waveform ( 15 ) and / or to a spurious signal synchronous filtering of Sensorrohsignals or a sensor signal waveform is performed. Method according to one of the preceding claims 14 to 16, wherein the reliability of the association between the sensor waveform and the state on the basis of the deviation between the sensor waveform and an approximating polynomial ( 27 ' ) and possibly displayed to the user or otherwise brought to the knowledge. Method according to one of claims 14 to 17, in which the at least one polynomial represents an approximation of the sensor waveform, the deviation of the approximation, d. H. the at least one polynomial, is determined by the sensor waveform, and the at least one polynomial is accepted as an approximation only if the deviation is below a predetermined limit value, wherein the limit value can be assigned to or dependent on a respective state or a polynomial subset associated therewith. The method of claim 18, wherein the deviation of the approximation is determined as a function or based on the sum of powers of the magnitudes of the differences between the values of the approximation and the corresponding values of the sensor waveform. A computer program product containing codes that enable a processor to perform the method of any one of claims 14 to 19.

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