WO2013150006A1

WO2013150006A1 - Fluid conveyor device and fluid conveyor method for medical uses

Info

Publication number: WO2013150006A1
Application number: PCT/EP2013/056905
Authority: WO
Inventors: Dominik Niedenzu
Original assignee: B. Braun Melsungen Ag
Priority date: 2012-04-02
Filing date: 2013-04-02
Publication date: 2013-10-10
Also published as: DE102012102850A1; EP2833943A1

Abstract

The invention relates to a fluid conveyor method and a fluid conveyor device for medical use, comprising at least one fluid source (1), at least one fluid sink (2), at least one fluid conduit (3) through which at least one fluid (4) can be guided from the at least one fluid source (1) to the at least one fluid sink (2), at least one fluid flow influence device (5) by means of which the fluid flow (6) in the at least one fluid conduit (3) can be influenced, at least one sensor device (7) for measuring at least one measurement variable (8) in order to describe a physical and/or chemical property or condition variable of the fluid, and an evaluation device (11) by means of which at least four values can be determined from a plurality of measurement values of the measurement variable (8), from which four values a sensor signal path (15) can be determined. At least one condition, which is defined by at least one polynomial family (28), can be assigned to the sensor signal path. The evaluation device (11) identifies at least one polynomial (27') from the polynomial family (28), which polynomial describes the sensor signal path.

Description

Fluid delivery device and fluid delivery method for medical

applications

The invention relates to a fluid delivery device for one or more medical applications. Furthermore, the invention is directed to a Fiuidförderverfahren 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 multiplicity of measured values of a measured variable is usually determined at a specific point in time, e.g. by using a "moving average" and compared to 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, typically at a particular point in time, two values are determined from a plurality of measured values of a measured variable, for example by applying a "moving average" (eg at two different times), and the difference between the two values or the ratio of the difference between the two values For example, it can be used to solve the described offset problem and to significantly reduce the drift problem (atypical drifts still apply) 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-alarming outliers can be caused, for example, by short-term disturbances, for example due to environmental influences such as

Vibrations occur that are not relevant to safety

Situation lead.

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 choose the threshold value himself, directly or indirectly - human error is thus a frequent source of error. Moreover, the user is generally deprived of the information about the reliability of detecting a critical situation (since it can not be validly determined on the basis of two values) - this complicates the appropriate response to e.g. 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 in

Claim 1 is defined, 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, this without the

aforementioned disadvantages of known methods allows. Advantageous embodiments of the invention are specified in the subclaims.

In one embodiment of the invention, the evaluation of the

Fluid conveying device designed such that at least four values from the plurality of measured values of the measured variable can be determined by them. With the expression values, in this file, the individual readings themselves or even

for example, from measuring sections or e.g. two or three or more individual measured values determined / certain / calculated values 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 delivery", "lack of delivery due to line blockage", "lack of fluid delivery due to exhaustion of fluid supply" or the like can be assigned to this sensor signal curve, such a state being defined by a polynomial community comprising at least one, preferably The evaluation device can use this polynomial set to determine a polynomial which describes the sensor signal profile, ie approximates it in the best possible way present, this Polynomschar assigned state detected.

One, several or all polynomial cohorts can in each case from

Polynom partial shares exist, so that the same state can be described by, for example, different polynomial partial shares.

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

Fig. 1 shows an embodiment of an inventive

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

3 shows an exemplary course of a measured variable,

Fig. 4 illustrates an exemplary course of a

raw sensor signal,

5 exemplifies the course of a sensor signal,

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

FIG. 7 shows an exemplary course of an optionally calibrated one

Sensor signal,

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

FIGS. 9 to 11 illustrate partial polynomials of the same exemplary state,

FIG. 12 shows a superimposed representation of all polynomial partial shares describing the same exemplary state according to FIGS. 9 to 11, all of which describe the same exemplary state,

FIG. 13 illustrates a partial polynomial for another exemplary state. FIG.

FIG. 14 shows a polynomial family for the same exemplary state as in FIG. 13, FIG. FIG. 15 illustrates an example of a sensor waveform and an approximation by a polynomial in a certain time interval, and FIG

Fig. 16 illustrates a superimposed representation of a sensor waveform, an associated approximation, and state sets, i. of states

defining polynomial shares or polynomial shares.

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 quantity indirectly related to a physical or chemical to be monitored

Property or state variable can be closed.

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 else a fluid, for example a contrast agent that is neither therapeutic nor

surgical treatment, however, for example

Examination recordings made better statements and results possible.

In the following, some examples of a measured variable associated with a fluid to be delivered will be described

Fluid conveying device described. 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 volumetric flow, a temperature, a density, a viscosity, concentration (for example of the fluid or

Fluid components), the color of the fluid or 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 electromagnetic radiation such as light, resonances, such 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 volumetric flow can be determined. As another example, the difference of the pressures of two points in a fluid line as a measured variable

be used.

The illustrated in Fig. 1 embodiment of an inventive

Fluid delivery device 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 interconnected by fluid lines 3 in the manner shown. With another

In the embodiment, the sensor device 7 can also be connected to the e.g. arranged as a pressure source formed fluid source 1 and e.g. be designed as a force sensor. The force sensor may e.g. attached to a syringe pump drive arm. The sensor device 7 may e.g. be placed as a pressure sensor on the hose wall of the fluid line 3. By the reference numeral 4 is in the

Fluid lines 3 flowing fluid called. An arrow 6 denotes the

Fluid flow and indicates the flow direction within the fluid conduits 3. As shown, the fluid flow influencing device 5 is arranged downstream of the fluid source 1. The sensor device 7 is provided in the embodiment according to FIG. 1 between the Fluidströmungsbeeinflussungseinrichtung 5 and the fluid sink 2, but may also be arranged elsewhere, such that they are a measurement of emerging from the fluid source 1 and in the direction of

Fluid sink 2 flowing fluid such as its pressure, flow rate, fluid quantity, etc. can sense. Connected to the sensor device 7 is an evaluation device 11 which evaluates the sensor signal generated by the sensor device 7 and which reproduces the measured parameter, such as the fluid flow.

In Fig. 2, the sensor device 7 and the evaluation device 11 are shown in greater detail including their internal configuration and interconnection. The sensor device 7 has one or more

Sensors 9, the or a sensor signal in the form of a sensor raw signal (10) generates / generate the course and size is evaluated.

Furthermore, a filter 12 is provided, which may be a noise filter, for example, but may also be or include a noise filter 13 and / or a calibration filter 14. The filter 12 is preferably used as a noise, Störsignal- and Kalibrierfilter. In the illustration according to FIG. 2, the filter 12 is arranged at the interface between the sensor device 7 and the evaluation device 11. However, the filter 12 may also be completely contained in the sensor device 7, or may also be part of the evaluation device 11. Possibly. can also be both in or at the output of the sensor device 7 and in or at the input of the evaluation device 1 1 each have a filter such as a noise filter,

Noise filter, calibration filter or the like may be provided, each filtering the raw sensor signal 10 or the sensor signal 15.

The evaluation device 1 1 has an evaluation element such as a

Microprocessor or microcontroller 27, 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.

If necessary, the processor 27 can have an approximation device 22, which can be designed, for example, in the sense of a digital signal processor DSP, enables a very rapid, effective signal evaluation, and determines at least one polynomial as an approximation of a sensor signal curve. The results generated by the processor 27 or the approximation device 22 can be stored, for example, in a memory device 21 and / or displayed in a display device 18.

The following are examples of data acquisition using the

Sensor device 7 shown and this also explains a measured variable 8 including its course, as shown for example in Fig. 3.

In the exemplary time course of the measurand 8 shown in FIG. 3, on the lower horizontal scale, i. the abscissa, the time axis plotted, while the actual value, ie the current size of the measured variable 8 on the vertical scale, i. the ordinate, is applied. 3, the measured variable 8 has the form of a straight line rising up to the time "0", superimposed on a sinusoidal interference signal, starting at the instant 0, a measured value collapse occurs up to approximately the time "300" (in this case

Numbers are, for example, a suitable time dimension of, for example, minutes, seconds or milliseconds or another

Ordinal number such as sample number). After a slight overshoot, the measured variable course returns to the actual extrapolation expected from the course up to time 0 at the time "600" and subsequently continues to grow at a disproportionately high rate in the short term or further up to the time 600 or 800, an estimate can be made as to whether the course of the measurement variable is a safety-critical disruption or other impairment and whether measures within the meaning of

Emergency actions or an alert should be taken.

In Fig. 3 the time course of the measured variable 8 is plotted. In general, however, the course of the measured variable 8 does not have to be a chronological progression. The measured variable 8 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

Progressive view of FIG. 3 is plotted on the lower horizontal axis not the time, but the location information to illustrate a cross section at a particular time as an example.

The spatial profile of a measured variable 8 associated with the fluid in the fluid conveying device may be, for example, the flow profile, e.g. on a section line parallel to the cross section of a fluid line. The airfoil may be, e.g. for cables with a circular cross-section

for example, as a parabolic profile.

In the following, the sensor 9 and a sensor raw signal waveform 10 shown as an example in FIG. 4 are explained in greater detail.

The illustrated in Fig. 4 time course of the sensor 9 of the

Sensor device 7 measured raw values, hereinafter as

Sensor raw signal waveform 10, differs in general from the actual course of the measured variable to be determined 8, which is exemplified in Figure 3. This may, for example, be due to the measurement technique or may be due to the fact that the measurement is due to random errors such as noise and / or systematic errors such as deviations due to

Production tolerances of the sensors is influenced, whereby the measurement results may be impaired or distorted.

As shown in FIG. 2, the sensor raw signal 10 can be filtered by the filter 12, for example in the form of a noise filter, such that the

Effects of disturbances such as signal noise are eliminated or at least reduced. By this filtering, the course of the (filtered) sensor signal 15 shown in FIG. 5 then results. The filter 12, such as the noise filter, can be part of the sensor device 7 as specified, for example, in the evaluation device 11, at the interface be provided between the sensor device 7 and the evaluation device 1 1 or can in divided shape in both the sensor device 7 and in the

Evaluation device 1 1 and possibly also at the interface between them

Components be arranged. Alternatively or in addition to the filter (noise filter) 12, the noise filter 13 and / or the calibration filter 14 may be provided. According to FIG. 2, these three filter types can be combined to form a common block. Alternatively, however, these filters may also be spatially separated, for example, the noise filter 12 may be arranged between the sensor 9 and the block 10 or following the block 15. Likewise, the calibration filter 14, if provided, be arranged before or after the blocks 10, 12, or 15. This also applies to the position of the noise filter in a similar manner.

The optionally provided noise signal filter 13 shown in FIG. 2 may, for example, filter the sensor raw signal 10 or a course of the sensor raw signal 10 already filtered by another filter, such as the filter 12 or 14, such that effects of disturbances, such as known systematic disturbances, which are caused for example by a cyclic noise, can be reduced or eliminated. At the output of the filter stage, the

For example, if the filters 12, 13 and / or 14 can comprise, then the course of the sensor signal 15 shown in FIG. 5 or FIG. 6 or FIG. 7 results. This sensor signal curve 15 can be generated, for example, by filtering and / or scanning synchronized with the interference signal become.

FIG. 6 shows the profile of the sensor signal with additional sampling, see the sampling points 15a.

A scanning synchronous to an interference signal can be effected, for example, by measuring the sensor only at the desired times (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, for example, a fixed sampling frequency is scanned synchronously to the interfering 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 corresponding to the actual samples at the respective (time) points. In another embodiment, instead of the time points in the scan may also be, for example, 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 which is to be filtered out, for example, by the interference signal filter 13, it may be an interference signal which as such already belongs to the time profile of the measured variable 8, and may be represented, for example, by a cyclical fluctuation in the volume flow passing through a conveying unit how about an infusion pump of the fluid delivery device is caused. As an alternative or in addition, such a disturbing signal can also be generated only by the scanning process or measuring process by the sensor device 7, for example caused by a 50 Hz noise.

The optionally provided calibration filter 14 can filter the raw sensor signal 10 or also an already filtered raw sensor signal, a sensor signal 15, in such a way that, for example, a systematic offset is eliminated or reduced and / or the signal is scaled. FIG. 7 shows the profile of a calibrated sensor signal 15 as an example. Only the filtered and calibrated measuring points 15a are shown, on the basis of which the further signal processing takes place.

8 illustrates a superimposition of the course of the original measured variable 8 and of the associated sensor signal curve 15, which is represented by the sequence of sensor signal points 15a.

In the following, an embodiment of a data processing will be explained in more detail. In this example, the evaluation device 11 at a given time, for example, at the time "800" on the abscissa

applied time scale, evaluate whether the sensor signal waveform 15 one of, for example, three predetermined states 18 ', 25, 26 can be assigned, and, if so, additionally determine which in Example 3

given 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. For this evaluation, a section of the sensor signal waveform 15 is considered which comprises a minimum of four values, but preferably 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 partial polynomial groups), as described in US Pat

The following example is explained.

The condition (s) may be e.g. to be 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 may be the dry up of the fluid source, for example by empty infusion containers. Another condition may represent a temporary dry up of the fluid source. Another condition may represent leakage in the system, not as an interruption of fluid delivery but as an undesirable pressure drop or reduced delivery at the outlet of the system

Fluid delivery system (for example, cannula) is detected.

The state I discussed below as an example is represented in FIG. 12 by the reference numeral 18 ', which comprises three polynomial partial shares 16, 19, 21', which in turn are reproduced in isolation in FIGS. 9, 10 and 11. In this case, in each case one of the three polynomial partial shares 16, 19, 21 'is shown in FIGS. 9 to 11. shown, which represent the state I in their entirety. FIGS. 9 to 11 each also show an approximation of an actually determined one

Represented sensor waveform associated polynomial and designated by the reference numerals 17, 20, 22 '. Each polynomial subset comprises a plurality of polynomials, each in the polynomial subset, i. the corresponding "polynomial" lie.

The polynomial underlying the polynomial set of state I 18 '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: Pi):

- et = ot_ _3> ! = a_ _2> , = a_ _u = 0 e [0, 0]

^' -5, 1 H 1 each [3500, 3900]

O _{L = -78.3 e [-78.3, -78.3]

«2 <= [0.658, 0.6595]

«3, 1 = - 1.9Ί0 e [-1.9 · 10 ³ , -1.9 · 10 ³ ]

a _{4 j} = 2.3 · 10 ^ e [2.3 · 10 ^"6 , 2.3 · 10 ^{" 6} } o ^ -io ⁹ ^ [-Itf ⁹ , -10- ⁹ ] -

This means, for example, that the following polynomial 17 belongs to the polynomial subset P ₁ :

3600-78.3 · / ,, + 0.6585 · / ;; - 1.9 · 1Ü ^~ V + 2.3 · ΙΟ ^"6 · ^ - Kf ⁹ ^

t P t P P

FIG. 9 shows the polynomial subset P116 of the state I 18 '.

FIG. 10 shows a parameter interval set 2 of the polynomial partial set P2 (19) and the polynomial 20. In terms of formula, this is defined as follows:

^Ά -5, 2 ^{= a} -4, 2 ^{= a} -3, 2 ^{= a} -2, 2 = «- 1, 2 = ^{0 e} [° ^> ° 1

2 e = [5500, 5800 y

ot _{j 2} = -78.3 e [-78.3, -78.3]

«2 ₂ e = [0.651, 0.65151

otj ₂ = -1.9-10 ^"3 e [-1.9- 10 ^{~ 3} , -1.9- 10 ^{~ 3} J

a _{4 2} = 2.3 · 10 ^ e = [2.3 · 10 ^" *, 2.3 · 10 ^{" 6} ] α _{5 2} = -10 ^"y e [-10 ^-9 , -10 ^-9 ]

This means, for example, that the following polynomial 20 belongs to the polynomial subset P ₂ :

5700-78.3 ·. ,, 4- 0.6513 - 1.9 ^■ 10 ^{~ 3} -i + 2.3 ΊΟ ^"6 -ij- 10 ^{" 9 ■}

f P P P

This is shown in FIG. 10 with the partial polynomial pair P2, 19, state I, 18 '.

FIG. 11 illustrates a parameter interval set 3 for the

Polynomial subset P3 (21 ') of the state I and the polynomial 22'. Where:

a-5 3 ⁼ 3 ^{= α} -3 3 ^{= a} -2 3 ^{= α} -1 3 ⁼ ^ ^e [0, 0] 3 e = [7000, 8000]

₃ = -78.3 e = [-78.3, -78.3]

3 e [0.66, 0.661]

«3 3 = -1.9 · 10 ^{" 3} e = [- 1.9 · 10 ^{~ 3} , -19-10 ^{~ 3} }

a ₄ 3 = 2.3 · 10 ^ e = [2.3 · 10 ^"6 , 2.3Ί0 ^{" 6} } ^α 5, 3 = KT ⁹ e [-KT ⁹ , -KT ⁹ ]

That is, e.g. the following polynomial 22 'belongs to the polynomial subset P3:

7500 -78.3 · / 4- 0.6605

P - P- 1.9 - 10 ³ -t 4- 2.3 · ΙΟ ^"6 · ^ - Kf

P P P

This is shown graphically in FIG. 11 with the polynomial subset P3 (21 ') of state I (18').

The state I with its three polynomial partial sets Pi, P ₂ and P ₃ can thus be represented as shown in FIG. 12.

Analogous to the above statements on the state I and the polynomial subgroups 16, 19, 21 'representing them, another state II which is represented by a single subset of polynomial, i. a polynomial crowd P4 is illustrated, which is illustrated in FIG. 13 by the reference numeral 23. In this polynomial crowd 23 runs, for example, by approximation of

The evaluation device 1 1 is thus able to recognize that the approximated sensor signal waveform 24 for

Part of polynomial 23 belongs, i. state II (25) is present, for example a partial or complete occlusion.

In Fig. 14, the polynomial crowd 25 is shown, which for the state II

is representative and identical in this embodiment, with the polynomial portion P4, 23. Hereinafter, the detection of the state II will be described in more detail with reference to the figures 13, 14:

The polynomial underlying the polynomial group of state II (25) has the polynomial degree N = 2:

N 2

fc fc

Further, the parameter interval set defining the polynomial set consists of M = 1 parameter interval sets with (2N + 1) = 5 parameter intervals, namely:

For polynomial fit r {2), which corresponds to that of tz 1: P ^: a-2,4 ^{= a} -l, 4 ^{= a} l, 4 ^{= 0 G} [°. °] o ^ ₄ e [4000,4300]

«2 ₄ e [-0.006, -0.003]

4 (^) = «0,4 ^{+ a} 2,4 ^' ^

This means that, for example, the following polynomial 24 belongs to the polynomial subset P ₄ :

4100-0.004- ^

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

In the exemplary embodiment illustrated, a state III (26) is defined by the fact that the (approximated) sensor signal does not belong to state I or state II, ie the approximated sensor signal waveform does not form part of the state Polynom partial shares 16, 19, 21 'or 23 is. Such a state III can be treated as undefined, for example, so that, for example, an indication, eg "disturbance", can be output.

In the evaluation device 11 is checked whether a sensor waveform 15 of a polynomial group (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 may be fixed or, for example, also proportional to the amplitude of the waveform, e.g. to 3% or 5% of the value of the waveform.

This polynomial is then referred to as approximation 27 'of the sensor waveform 15 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 under consideration is equal to or smaller than the limit value, the one of these different polynomials is selected for an advantageous, optional embodiment, for which the deviation from

Sensor waveform is the lowest. This polynomial is then in this

Special case as approximation 27 'of the sensor signal waveform further processed.

FIG. 15 graphically illustrates the sensor waveform 15 with the samples 15a and the approximation 27 '. Again, on the abscissa is the

Plotted time scale, while on the ordinate the values of the sensor signal or the approximation are plotted. According to FIG. 15, the considered time range is again the time segment from 0 to 800, where the approximation 27 'corresponds here sufficiently precisely to the actual course illustrated by the values 15a. FIG. 16 shows a superposition of the representations according to FIGS. 12, 14, 15 in order to illustrate the subset of polynomials, the sensor signal profile and the approximating polynomial.

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, i.e., lies "inside" the "polynomial tubes" which are spanned thereby. This can be especially true if the

Sensor waveform should not belong to one of the polynomial shares or polynomial shares, reduce the processing cost considerably. If it is detected that the sensor waveform does not become one of the polynomial shares or

Polynomial partial sets corresponding to the respectively defined states, e.g. State I or state II, the further processing can be aborted. It is therefore with little effort and very quickly before a meaningful result, which indicates, for example, that the current state of the fluid delivery, for. can not be estimated. The processing may then be e.g. be canceled, so that the processing effort is minimized, and it can be a

Error message or fault message or even just a warning to be issued, e.g. 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, the deviation of which lies below a predefined limit value, for example, analogous to CurveFits with constraints. This allows the Increase processing speed in some cases, as the curve may converge faster.

On the other hand, if it is determined that there is a good feed 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 a dangerous condition is detected, such as too little or a total lack of fluid delivery, since the sensor waveform

If, for example, a polynomial group or polynomial subgroup assigned to this hazardous condition is present, a different kind of warning can be given by, for example, a red warning light illuminating and / or an audible warning being emitted.

In a further embodiment, all or any arbitrary part of the above-described features of the previously described

Embodiments may be provided to check where the polynomial approximating the sensor waveform within the associated polynomial

Polynomial group or polynomial component, i. 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 is stored and / or one

For example, green lamp 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 tube, a warning may be given that the system is operating close to its proper limit and the danger of leaving the associated one soon

Polynomial tube exists. 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 reliability / quality / quality may alternatively or additionally be based on the deviation of the approximating polynomial from the

Sensor waveform based.

In this exemplary embodiment, it is provided to detect what distance the polynomial approximating the sensor signal profile from the boundaries of the associated polynomial group or polynomial subgroup complies with, for example a situation in which the approximating polynomial is in the middle range of

For example, 40% to 60% of the polynomial hose width at the site is considered to be 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 becomes a warning condition

If the approximating polynomial should be in the range of 0% to 20% or 80% to 100% of the current polynomial width, ie near or right on the edge of the polynomial set or polynomial set, this condition may be referred to as "yellow". dangerous "classified and given, for example, a corresponding acoustic, visual or visual display.

Also, the speed of approximation of the approximating polynomial to the limits of the polynomial (partial) sharp can be determined and at high

Speed early warning of the imminent departure of the desired functional area will be given.

In the embodiments described above, the fluid source 1 may for example correspond to an infusion container, which has a

Infusion tube as fluid line 3 or fluid flow tube with a device or a patient can be connected as a fluid sink 2. When

Fluid flow influencing device 5 may be provided in this case, for example, a hose clamp for changing the cross section of the infusion tube and thus to influence the infusion flow. But it can also be used a syringe pump or the like. When Fluid flow influencing device 5 may alternatively or additionally also be provided a peristaltic pump or an infusion pump, for example, 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 together with syringe together 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 combined on a common hose or fluid line 3 via check valves and two-, three- or multi-way valves. 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, to the fluid sink 2, such as a patient, infusion line leading, for example, a 2-lumen catheter may be provided which can open 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 over

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 machine, which as

Fluidfluidbeeinflussungseinrichtung 5 and may contain, for example, filters and so on. In such a configuration is additionally a

Waste container 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 may in this case 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 may be provided for eg 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. Here, the cartridge with the diabetes agent serves as the fluid source 1, while the pump of the implant serves as the fluid flow influencing device 5 and the patient functions as a fluid sink 2. In this case, the fluid flow between the outlet from the cartridge and the needle end is detected by the sensor device 7.

In a further embodiment of the invention

Fluid delivery device and the fluid delivery process according to the invention is an intelligent, dynamic pressure monitoring realized.

In this embodiment, the pressure of the fluid to be delivered in the infusion line by measuring the force of the syringe plunger plate on the

Drive arm of a syringe pump or the force measured on a pressed onto the infusion line pressure sensor of a peristaltic pump or the like, particularly advantageous while a synchronous to the drive unit of the pump is used to determine the sensor signal 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 goal of pressure monitoring is in this embodiment in Ensuring a constant, steady, uniform and / or undisturbed promotion with 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 with regard to their significance, for example with regard to "good delivery rate", "critical delivery rate", "insufficient or excessive delivery rate", "uniform delivery", "non-uniform delivery", "Undisturbed conveyance", "disturbed conveyance", etc. In any case, the pressure monitoring can ensure a steady supply of fluid or indicate deviations therefrom.

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 in the system may be occluded by blocked filters or the like, by squeezed lumens, such as a multi-lumen catheter

Check valves or be caused by other weaknesses.

Also at the syringe problems can be caused by blockages. For example, the syringe piston due to the friction between

Piston seal and cylinder despite e.g. 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

To effectively push syringe plungers inward and to infuse the fluid.

Embodiments of the fluid delivery device according to the invention and of the fluid delivery method according to the invention offer the advantages that they have Pressure offsets caused by, for example, height differences such as the suspension of an infusion container or different syringe friction 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, there are no manual interventions or adjustments,

for example, regarding the entry of limit values required.

The embodiments of the fluid delivery device according to the invention and the corresponding method are also characterized by rapid

Responses, for example, to critical disturbances, since these

for example, in their tendency already can be detected 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 the polynomial and the 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. So it is also possible, a certain

Predict whether the system conditions are changing in the direction of improvement or deterioration. For some

Embodiments may also take place a pre-alarm in the case of an imminent, but not yet occlusion. On a display screen the

Fluid conveying device according to the invention can at one or more

For example, icons indicating whether the device is off, in idle, an initialization phase may be presented passes through or is in normal operation. Further, it may be possible to visually display predictions indicating, for example, that the apparatus, ie, the fluid delivery device, is moving within a correct range with the correct baseline or shortly thereafter Also, a prediction may be displayed indicating an occlusion is imminent or there is a line leak.

In embodiments of the fluid delivery device according to the invention and the method according to the invention thus a statistical approach for signal processing is used in which curve fits, splines, regressions or the like can be used. This makes a difference

Threshold methods in which, for example, only on the basis of moving averages ("sliding averages") or the like is used.

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 does not have to be the same fluid throughout, but it is also possible, for example, to use two fluids in one conduit

Mix fluid sources. 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 can also be a living being and, if appropriate, the fluid source and the fluid sink can also be connected to one another directly, for example, so that a delivery cycle can be established. 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 the method according to the invention may also have uncontrolled components for fluid delivery. The

For example, in embodiments of the present invention, 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 on the fluid source, on 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 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 to

Guiding the at least one fluid from the at least one 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 for describing a physical and / or chemical property or state variable of the fluid, and a

Evaluation device and optionally a filter device comprises. The

Evaluation device is designed to determine from a plurality 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 the evaluation is a polynomial of the at least one

Polynomial crowd determinable. 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 occlusion, is present, so that if necessary very quickly initiated countermeasures or warnings can be generated.

The polynomial preferably represents an approximation of the

An approximation is considered given if the

Deviation between the approximating polynomial and the sensor waveform is below a predetermined threshold associated with the particular state or polynomial constituent portion of 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 contains the least deviation from the polynomial is contained

Having sensor waveform.

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 synchronizes to an interference signal

Scanning the sensor waveform or the Sensorrohsignalverlaufs performs. 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

Measurement ranges whose width is e.g. may be significantly smaller than a period of the interfering signal, e.g. 1% to 30% or 92% to 100% of this period, in the

Filtering process, whereas the filtering for the intervening Areas may be exposed. 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

Assignment between the sensor waveform and the state 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 e.g. to 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, colorant, conductivity, compressibility, brightness, or spectroscopic Sensor or the like act. 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. the fluid sink agree. For some

Embodiments may also include multiple fluid sources and / or fluid conduits and / or destinations, i. 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.

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

The force acting on the fluid can by arrangement and / or

Dimensioning of the fluid source and / or the fluid line and / or the

Destinations or the fluid sink can be generated or influenced.

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. in the Fluidfördervornchtung or in a part of the Fluidfördervornchtung in one or more defined or known changes in the volume of the device or part of the device, such as compression or decompression, to the amount of existing in the volume considered fluid or part of the fluid, in particular a gas 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. With that you can

Fluid supply fluctuations due to trapped air, can be reduced or avoided.

For example, the ideal gas state equation, the law of Boyle-Mariotte, the Law of Gay-Lussac or the law of Amontons can 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 waveform If no predefined course can be assigned in the sense of a polynomial group and thus the state can not be detected because the approximating polynomial can not be attributed to a polynomial group, the fluid conveying device can be designed for a certain time to take measures that encourage a possible operator to act to force or force such as one

Emergency shutdown and emergency repair, to dispense. 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 the restoration of a known state, an action request is subsequently issued and / or entered, for example in acoustic or optical form

Device intervention such as a shutdown, a change in the delivery conditions or the like 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, ie, 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.

In the event of improper condition and / or operation of the

Fluid delivery device may be, for example, a closure (occlusion) or partial closure of the fluid conduit, the temporary or permanent

Failure of the fluid source and / or leakage in the system, i. in the

Fluid conveying device, act.

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

In the context 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

claims

1. Fluid delivery device for a medical application, with

at least one fluid component (1) which is designed such that at least one fluid (4) can be discharged through it,

at least one fluid sink (2), which is designed such 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 through it by the at least one fluid line (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 measure at least one measured variable (8) for describing a physical and / or chemical property or state variable of the fluid, and

an evaluation device (11), which is designed to determine from a plurality of measured values of the measured variable (8) at least four values, from which a sensor signal waveform (15) can be determined to which at least one state can be assigned, wherein the at least one state at least one polynomial group (28) is defined,

wherein the evaluation device (11) is designed to determine at least one polynomial (27 ') from the polynomial group (28), wherein the at least one polynomial (27') describes the sensor signal profile.

The fluid delivery apparatus of claim 1, wherein the polynomial group consists of M polynomial subgroups, 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 polynomials

Nth degree / ^ () = ΣΪ ^a k · ^{ ϊ, whose parameters a _{km are} all in the respective associated parameter interval] b _{k> m} , e _{k> m} [.

3. fluid handling device according to claim 2, wherein "^ in the amount of Parameterintervaiien essentially a (3xM) -elementige ^amount"], ^[/) ". ^{, £} '"".] ^{// / (} / [/ ⁾ , ". ^{, £} · "]} _{DZW to} their open or semi-open equivalents, or t ^()]] ~ ^00th ⁰⁰ [wul [h _{] m} ^, e _L J} _DZW whose open or half-open correspondences.

4. fluid handling device according to claim 2, wherein -elementige in the set of parameter intervals essentially a (3xM) Quantity ir »· ^<■. '-.. I» J * V \ <"''i.<n ^([0]} fo _tw j _older open or semi-open matches or \ ^"c]."]} ~ ^■ °° · °° [ »» ί / [0]} or their open or semi-open. Correspondences acts.

5. Fluid delivery device according to one of the preceding claims, wherein the at least one polynomial represents an approximation of the sensor signal waveform.

6. A fluid delivery device according to claim 5, adapted to measure the deviation of the approximation, i. of the at least one polynomial to determine from the sensor waveform and to accept the at least one polynomial as an approximation only if the deviation is below a predetermined threshold, the threshold may be associated with or dependent on a respective state or polynomial constituent associated therewith ,

7. The fluid delivery apparatus of claim 6, configured 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.

8. Fluid delivery device according to one of the preceding claims, wherein the evaluation device (1 1) is adapted to determine a plurality of polynomials and assign the sensor waveform to the state in its polynomial cohort that polynomial is included that has the least deviation from the

Having sensor waveform.

9. fluid delivery device, in particular according to one of the preceding claims, which is adapted to a disturbance to a synchronous sampling of the measured variable (8) or a Sensorrohsignals (10) or the sensor signal waveform (15) and / or synchronous to a disturbance filtering of the Sensorrohsignals or a sensor waveform.

10. The fluid delivery device according to claim 1, which is designed to evaluate the reliability of the association between the sensor signal course and the state and / or the quality of a state and / or its detection on the basis of a possibly existing deviation and to inform the user, for example in the form of an advertisement.

1 1. 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.

12. 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

13. Fluid delivery device according to one of the preceding claims, wherein the evaluation device (1 1) is formed as part of an infusion pump or is in communication with such.

14. A fluid delivery method for medical use, in which at least one fluid (4) can be conducted from at least one fluid source (1) to at least one fluid sink (2) through at least one fluid line (3),

wherein the fluid flow (6) in the at least one fluid line (3) by a Fluidströmungsbeeinflussungseinrichtung (5) can be influenced and at least one measured variable (8) for describing a physical and / or chemical property or state variable of the fluid by a sensor device (7) is measured .

wherein at least four values are determined from a multiplicity of measured values of the measured variable (8) from which a sensor signal course (15) is determined, to which at least one state is assigned or is assigned,

wherein the state (18 ') is defined by a polynomial group (28) and at least one polynomial (27') is determined from the polynomial group (28) describing the sensor waveform.

15. The method of claim 14, wherein the polynomial set 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 polynomials

Nth degree / _/ ) = X, a _km - ή, whose parameters a _{km are} all in the respectively associated parameter interval] b _km , e _km [lie.

16. The method according to claim 14 or 15, wherein a synchronous to a disturbance signal sampling of the measured variable (8) or a Sensorrohsignals (10) or the sensor waveform (15) and / or to a disturbance signal synchronous filtering of Sensorrohsignals or a sensor waveform is performed ,

17. The method according to any one of the preceding claims 14 to 16, wherein the reliability of the association between the sensor waveform and the state based on the deviation between the sensor waveform and an approximating polynomial (27 ') evaluated and possibly displayed to the user or otherwise brought to the knowledge.

18. The method according to any one of claims 14 to 17, wherein

the at least one polynomial represents an approximation of the sensor waveform,

the deviation of the approximation, i. the at least one polynomial, is determined by the sensor waveform, and

the at least one polynomial is only accepted as an approximation 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.

19. 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.

Computer program product containing codes, by which a processor for carrying out the method according to one of claims 14 to 19 can be initiated.