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    • 专利摘要:
    The invention relates to a method and a device for validating a continuously measuring, non-invasive blood pressure measuring system (202) which is equipped with a plethysmographic system (203, 204) which is suitable - in a measuring phase - a plethysmographic signal v (t) to gain on an extremity (101), with a control mechanism (206) to which the signal v (t) from the plethysmographic system (203, 204) is supplied, which via a control value u (t) the contact pressure pC (t) on the Extremity (201) changed, and with an evaluation unit which continuously determines the course of the arterial blood pressure pA (t) based on the resulting contact pressure pC (t). According to the invention, the blood pressure measuring system (202) has a coupling interface (209) via which - in a validation or test phase - a signal derived from a previously recorded blood pressure curve can be coupled into the blood pressure measuring system (202).
    公开号:AT522324A4
    申请号:T50469/2019
    申请日:2019-05-22
    公开日:2020-10-15
    发明作者:FORTIN Jürgen；Fellner Christian；Grond Julian；Lerche Katja；Brunner Thomas
    申请人:Cnsystems Medizintechnik Gmbh；
    IPC主号:
    专利说明:

    The invention relates to a method and a device for validating a continuously measuring, non-invasive blood pressure measuring system, which is equipped with a plethysmographic system that is suitable for obtaining a plethysmographic signal on an extremity that is fed to a control mechanism that applies a contact pressure to the Extremity changed, based on the contact pressure the course of the arterial
    Blood pressure is continuously determined.
    The present invention describes test systems or simulators and the associated validation methods for continuously measuring, non-invasive blood pressure measuring devices (Continuous Non-invasive Arterial Pressure CNAP). The measuring methods of the CNAP devices are often also called "Penaz Principle", "Vascular Unloading Technique" or "Volume Clamp Method", with newer measuring methods based on these basic principles described below
    go out.
    These CNAP devices record a living being's blood pressure signal in real time without the need to insert a catheter into the arterial vasculature. The accuracy of these CNAP devices compared to the actual intra-arterial blood pressure has increased enormously in the recent past due to new types of measurement sensors and new methods (algorithms) and it is to be expected that daily clinical use will no longer be imaginable without them in the future. For acceptance in clinical use it will be necessary to check the accuracy at regular intervals. In particular, when it comes to regulatory approval and the subsequent placing on the market of new CNAP devices or their algorithms (methods that are mapped in software) are standardized
    Test systems, simulators and validation procedures necessary.
    In the CNAP systems for continuous blood pressure measurement, the blood pressure signal is recorded on an extremity (usually on the finger) using a special method and device. The device has signal pickups for the acquisition of a so-called plethysmographic signal (volume signal) v (t) and means for the
    Change of the contact pressure (counterpressure) pc (t) of the sensor system.
    The measurement methods for these continuous CNAP systems essentially work according to the following logic: First, the contact pressure pco (t) is determined at which the pulsations in the volume signal v (t) become maximum. According to the so-called “oscillometric principle” or “principle of maximum amplitude”, the contact pressure pco (t) at this point corresponds to the mean arterial blood pressure mBP. The search for the maximum pulsations in v (t) and thus for mBP, whereby the contact pressure pc (t) is changed successively, is called
    according to the state of the art "open-loop phase".
    If pco (t) has been found, the so-called "closed loop phase" begins. In this actual measurement phase, the CNAP system tries to continuously maintain the oscillometric principle by means of a closed control loop. In concrete terms, the contact pressure pc (t) of CNAP follows the natural fluctuations in the actual arterial
    Blood pressure pa (t), whereby the amplitude of the pulsations is always maximized.
    The known CNAP procedures now differ in how it is ensured that
    the system is at the point of maximum pulsation:
    The method for determining blood pressure without blood was presented in 1973 by Jan PENAZ (Digest of the 10th International Conference on Medical and Biological Engineering 1973 Dresden). The "Vascular Unloading Technique" or "Volume Clamp Method" is therefore also named after the inventor "Penaz Principle". A finger is x-rayed and a servo control applies pressure to the finger in such a way that the originally pulsatile flow registered by the x-ray is kept constant with the help of an electropneumatic control circuit. The "principle of maximum amplitude" can be adhered to as long as there are no changes due to the smooth
    Vascular muscles (vasomotor functions) occur.
    This disadvantage was eliminated in accordance with US Pat. No. 4,510,940 A (WESSELIG), the "closed-loop phase" being regularly interrupted. In the following "open loop phase" a new
    brief search for the maximum amplitudes performed according to given criteria.
    Both PENAZ and WESSELING use only one control loop for their method, which is intended to regulate all disturbance variables. In US 8,114,025 B2 (FORTIN) a new CNAP method
    described, in which interlocking concentric control loops for each one specific
    Disturbance variables are responsible. In US Pat. No. 8,814,800 B2 (FORTIN), the "principle of maximum amplitude" is further improved; after each heartbeat, the correctness of the principle is checked by adding a special property of the pulse shape to correct the
    Working point is used.
    US 10,098,554 B2 (FORTIN) describes a new CNAP principle that deviates from the simple "Volume Clamp Method": the contact pressure pc (t) no longer acts in a pulsatile manner on the extremity, but only slowly follows the changes in the middle arterial blood pressure mBP. The pulsatile nature of the continuous blood pressure curve is obtained from the pulsatile plethysmographic signal v (t). In WO 2016/110781 a
    Variant of a portable blood pressure measuring system (CNAP-2-GO) described.
    It is true of all known systems that they only work if an extremity (e.g. the
    Finger) of a living being is brought into contact with the measuring sensors.
    The object of the invention is to improve a method and a device for validating a continuously measuring, non-invasive blood pressure measuring system in such a way that no extremity (for example a finger) is used to validate the blood pressure measuring system
    the device must be brought into contact.
    According to the invention, this is achieved in that - in a validation or test phase - a signal derived from a previously recorded blood pressure curve via a
    Coupling interface is fed into the blood pressure measurement system.
    Advantageous variants of the validation method according to the invention are in the dependent
    Method claims 2 to 10 set out.
    A device according to the invention for validating a continuously measuring, non-invasive blood pressure measuring system, which is equipped with a plethysmographic system which is suitable - in a measuring phase - to obtain a plethysmographic signal v (t) on an extremity, is characterized in that the blood pressure measuring system has a Has coupling interface via which - in a validation or test phase - a signal derived from a previously recorded blood pressure profile into the blood pressure measuring system
    can be coupled.
    Advantageous variants of the device according to the invention are set out in the dependent claims
    12 to 15.
    The device according to the invention and the method according to the invention differ fundamentally from known test systems which are used for the validation of, for example, intermittent blood pressure measuring devices. These intermittent blood pressure monitors usually measure the currently occurring blood pressure on the upper arm or wrist in a point measurement without showing the continuous progression. The cuff is inflated above the systolic blood pressure value and then the pressure is slowly released. You then get exactly one systolic, mean or diastolic value per inflation process, which usually lasts up to one minute. The evaluation methods of intermittent blood pressure measurement methods are usually the auscultatory method according to Riva-Roceci (1896) / Korotkow (1905), in which the noises in the crook of the arm are listened to using a stethoscope, or the oscillometric method
    Process that is often used in automatically functioning devices.
    In the literature, test systems for intermittent blood pressure measuring devices are described in which the oscillometric pulses or "Korotkow tones" are artificially introduced into the blood pressure measuring device to be tested in order to enable the measurement of a given blood pressure value. These test systems cannot be used for continuous measuring CNAP systems; they can neither close the control loop necessary for these CNAP systems nor the physiological properties of the extremity (e.g.
    Finger).
    The methods described in the beginning of the prior art have one thing in common: the closed CNAP control system tries in the "closed loop phase" the volume changes v (t) or according to US 10,098,554 B2 certain frequency contents of v (t) (referred to as vs ( t)) to keep constant by changing the contact pressure pc (t). As will be described later in detail, v (t) or certain frequency contents v. (T) indicate how large the deviation from the current contact pressure pc (t) to the actual arterial blood pressure pa (t) is, since the deviations pc (t) - pa (t) also result in volume changes. In the language of system and control engineering, v (t) or vf (t) corresponds to the control deviation, also referred to as the error signal e (t). If the control deviation e (t) is sufficiently small, pa (t)
    be reconstructed with sufficient accuracy from pc (t) - of course without pa (t) using
    invasive catheter needs to determine what the great advantage of these CNAP systems is. In the more recent methods according to US 10,098,554 B2 and WO 2016/110781 A1, for the
    Determination of the pulsatile pa (t) besides pc (t) also requires further frequency contents of v (t).
    An essential feature of all CNAP systems is the fact that the comparative element of the controlled system - i.e. the place where the "reference variable" pA (t) is compared with the "controlled variable" pc (t) - is in the body or in the extremity of the living being. From a control point of view, it is irrelevant where the so-called "comparator" is located. In practice, however, this means that a conventional CNAP system only works if an extremity or a finger of a living being is available - i.e.
    even if the CNAP system is to be tested or validated.
    The exact reference variable - i.e. the actual arterial blood pressure pa (t) - is therefore not available to the CNAP system; it only receives the plethysmographic information, i.e. a signal corresponding to changes in the volume v (t) of the artery. This information is usually obtained by a light process in which a light source (e.g. LED) is attached to one side of the extremity (e.g. finger) and the transmitted signal is measured (e.g. using a photodiode) on the other side. In all known systems, the light source emits light with constant light intensity, or in most cases constant, rectangular light pulses are used. The use of light pulses allows, on the one hand, a higher energy density with simultaneously reduced energy expenditure and, on the other hand, allows the ambient light to be recorded during the so-called blanking interval. Lighting systems for CNAP devices are for example in US 8,343,062 B2 (FORTIN)
    described.
    So far, the reference variable pa (t) could only be incorporated into a CNAP system if an extremity (e.g. finger) of a living being is present. Logically, only the subject's current blood pressure can be measured. For regulatory reasons, this is a major disadvantage, as standardized, repeatable test measurements cannot be carried out. Systematic investigations of the CNAP system are not possible in this way, in contrast to other biomedical systems such as With the ECG or the previously mentioned test systems for intermittent blood pressure monitors, signals that have been recorded once cannot be imported and tested repeatedly. Problematic
    Blood pressure curves such as Drop in blood pressure during operations, asystoles
    Tilt table examinations, changes during different pacemaker settings, etc. cannot be reproduced. Changes to the CNAP system must be validated for regulatory reasons, which, according to the state of the art, is only possible through repeated test measurements on the patient in the clinic. Since such problematic blood pressure curves cannot be predicted, measurements are also required
    necessary for a large number of patients in order to obtain statistically significant information.
    The present invention now enables standardized validation measurements to be carried out. In the following, several design variants of devices and
    Procedure for validation of CNAP systems described.
    A basic method for feeding in the previously recorded blood pressure curve as a reference variable pa (t) is done by modulating the light, specifically by modulating the LED light pulses. In the device according to the invention, the CNAP system can no longer distinguish whether the resulting light signal v (t) was generated on the receiving side by a simulation module of the device, or whether the modulation originates from a person's finger. The CNAP system then generates a contact pressure pc (t) via the described controlled system, from which the arterial blood pressure pa (t) to be determined can be derived. The controlled variable pc (t) is in turn imported into the simulation module and compared with the ongoing recorded reference variable pa (t). A new v (t) is generated and again via a modulation of the light
    imported into the system and the control loop was closed.
    It is thus possible that a clinically recorded blood pressure curve - more precisely the blood pressure signal of a patient that has been recorded once - can be imported into the CNAP system to be tested. The resulting measurement signal can now be compared with the input signal. It is irrelevant whether the patient signal comes from an intra-arterial catheter or whether it comes from a CNAP device that was used during the clinical
    Measurement was used.
    The invention further describes validation methods of CNAP systems that can be carried out with the present test system or simulator, as well as methods that provide equivalence between already approved CNAP systems and new, modified systems
    can prove.
    7728
    The invention is explained in more detail below on the basis of exemplary embodiments. It
    demonstrate:
    1 shows a blood pressure measuring system in a schematic representation with a CNAP control circuit
    according to the state of the art in the measurement phase;
    2 shows a validation device according to the invention with a blood pressure measuring system
    according to FIG. 1;
    FIGS. 3a and 3b are diagrams of LED pulses;
    4a and 4b p-v diagrams for determining the setpoint; as
    5a to 5d validation method using a “tolerance triangle”.
    1 shows a blood pressure measuring system 102 according to the prior art, which uses the following technical control methods for continuous non-invasive CNAP methods for determining the blood pressure signal pa (t): To an extremity 101 or a part of the body of a living being in which an artery A is located - such as the finger 101, a wrist or temple - a plethysmographic system 103, 104, for example in the form of a finger cuff 105, is attached and thus illuminated by means of a light source 103. The light that flows through this extremity 101 or is reflected on the bone lying in the extremity (e.g. wrist, temple) is registered with a suitable light detector 104 and is an inverse measure of the arterial blood volume in the extremity (plethysmographic signal v (t) ). The more blood there is in the limb,
    the more light is absorbed and the smaller the plethysmographic signal v (t).
    The signal v (t) is now fed to a control mechanism 106 and a control value u (t) is determined, which subsequently changes the contact pressure pce (t) on the extremity 101 generated by a pressure generation unit 108. The contact pressure pC (t) acts at the point where the plethysmographic signal v (t) is also determined. The condition of the control mechanism stipulates that v (t) or certain frequency contents of v (t) (referred to as vs (t)) are kept constant by the applied contact pressure pc (t). If thus v (t) wants to change, then the regulator mechanism 106 sets the pressure via the manipulated variable u (t)
    pc (t) in such a way that v (t) remains constant.
    If this rule condition is observed - i.e. v (t) and thus the blood volume in the extremity 101 remain constant over time - then the pressure difference between the intra-arterial pressure pa (t) and the external contact pressure pc (t) is the so-called transmural Pressure p + (t) - equal to zero. The contact pressure pc (t) thus corresponds to the intra-arterial pressure pa (t) in the extremity. This contact pressure pc (t) provided by the pressure generating unit 108 can be measured by means of a pressure sensor or manometer
    will.
    An essential component, namely the comparator of the controlled system, is located inside the extremity (e.g. finger). The so-called comparator is the comparison element in which the "reference variable" pA (t) is compared with the "controlled variable" pc (t). If pa (t) changes compared to pc (t), then there are volume fluctuations that exceed the
    plethysmographic signal v (t) can be recorded.
    The control loop according to FIG. 1 thus only functions if the human comparator - that is to say the extremity 101 or the finger - is also introduced into the CNAP system. This human comparator in the form of a test person, or more precisely the comparator function - previously had to be present when the devices were checked or validated. The current blood pressure in the artery of the test person pa (t) is thus compared with the contact pressure pc (t)
    compared and the basic comparator function
    v (t) = f (pc (t) - pa (t)) (1)
    is generated. The current blood pressure in the artery pa (t) is also not directly available to the CNAP system, which is the advantage of this non-invasive CNAP system. But this also makes it - in comparison to other test systems such as For EKG or the previously mentioned test systems for intermittent blood pressure measuring devices - it is not possible that a biological signal is simply introduced to a measuring sensor and the device to be tested generates a measured value. The biological signal available to a CNAP system will be yes
    directly influenced and changed by the measuring method or the contact pressure pc (t).
    For checking, testing and validation of CNAP systems, it is advantageous if the
    Comparator function can be made available in a standardized way, as follows
    on the basis of design variants of validation procedures and validation devices
    is described.
    FIG. 2 shows a block diagram of the validation device according to the invention. Instead of the extremity or the finger, a simple finger dummy 201 is in contact with the plethysmographic system 203, 204. The plethysmographic signal v (t) is generated by means of the light source 203 and a light sensor 204. The signal v (t) is fed to the control mechanism 206 and a manipulated variable u (t) is determined, which subsequently has a
    Contact pressure pc (t) changed.
    In this variant, care is taken to ensure that the same CNAP components are active as are also used according to the prior art from FIG. This is necessary for the verification of validation described later. Ideally, the CNAP devices are designed in such a way that they are put into a simulator mode and thus can virtually validate themselves. The components of the blood pressure measuring system 202 in FIG. 2 thus correspond to those of the blood pressure measuring system 102 from FIG. 1; the light source 203 of the light source
    103, etc. The additional system components are explained as follows according to Figure 2:
    The finger dummy 201 is primarily responsible for the fact that the contact pressure pc (t) provided by the pressure generation unit 208 can actually occur in the blood pressure measuring system 202 in that the contact pressure pc (t) hits a counterpart. The contact pressure pc (t) is often generated by means of an inflatable finger cuff 205, this one
    The cuff could even burst if there is no counterpart.
    Furthermore, the finger dummy 201 should have similar haptic properties as an actual finger. In particular the viscosity properties are to be simulated by e.g. a gel or gelatin is used as the material for the finger dummy 201, which is surrounded with an elastic skin. This is advantageous for coupling the light source
    203 and light sensors 204 to simulate.
    The finger dummy 201 preferably has optical properties that are similar to those of an actual finger of a living being. The absorption constant of the finger dummy 201 is selected, for example, for the light wavelength occurring in the light source 203, as shown in FIG
    a finger occurs with a contact pressure pc (t) above the systolic blood pressure
    is pressed. The amount of light that is shone through by a finger, which is constricted by the systolic blood pressure, should at least also be transmitted by the finger dummy 201
    can be transferred, but not much more.
    The finger dummy 201 thus fulfills minimum haptic and visual requirements; however, in contrast to an actual finger, it does not have to modulate the light signal in order to do so
    Bringing information about the arterial blood pressure pa (t) into the CNAP system.
    According to the invention, this should work by modulating the light source 203. In the measurement phase according to FIG. 1, the light source 103 always shines with constant light energy. This light energy should now be able to be changed or modulated via a coupling interface 209 in a validation or test phase. The light modulated in this way now flows through the finger dummy 201 and hits the light sensor 204. This receives the light regardless of whether the light modulations are caused by changes in the absorption in a finger or by modulating the light intensity in the light source 203 the resulting signal v (t) is fed to the control mechanism 206, which determines a control value u (t), and subsequently changes the contact pressure pc (t), which
    in turn acts on the finger dummy 201.
    What is still missing is the comparison element or comparator required for every control system, in which the reference variable pa (t) is compared with the controlled variable pc (t). For this purpose, a simulation module 210 is provided which, on the one hand, receives the contact pressure pc (t) of the blood pressure measuring system 202 as input parameters, as well as a blood pressure profile pa (t) previously recorded on a storage medium 211. The simulation module 210 calculates the plethysmographic signal v (t) according to equation (1) - the so-called comparator function of the simulation module 210 - and feeds it to the coupling interface 209 in order to carry out the modulation
    of the light in the light source 203 to ensure.
    FIGS. 3a and 3b show the changes in the control of the light source 103 (FIG. 1: measurement phase or prior art) and 203 (FIG. 2: validation phase of the invention), LEDs preferably being used as light sources 103, 203 . It is known that the signal yield of an LED is better if the LED is controlled with electronic pulses. In this way, higher LED currents can be generated for a short time, although the total energy consumption
    the LED is reduced. The information about the switch-on times of the pulses are provided to the
    Light receiver 104, 204 communicated. FIG. 3a shows such electronic control pulses during the measurement phase. There are only control pulses that either completely control the light source 103
    switch on (state 1) or switch off (state 0).
    FIG. 3b now shows how the energy of the switch-on pulses can be modulated. So that the complete information of a blood pressure curve can be modulated and thus transmitted into the CNAP system via the light source 203, the height of the electronic pulse should be equipped with at least 12 bit coding up to a maximum of approx. 16 bit coding. All
    other codings are also possible according to the invention.
    Figures 4a and 4b show a typical pressure-volume diagram (p-v diagram). This information is necessary to determine the function from equation (1) and thus to describe the comparator function of the simulation module 210 in the following. The p-v diagram is usually determined in the open-loop phase, i.e. at the beginning of each measurement, where according to the "oscillometric principle" or the "principle of maximum amplitude" after the maximum pulsations and thus according to the mean arterial blood pressure mBP wanted
    becomes.
    In Figure 4a it is shown that at the point:
    v (t) = maximum pulsations / contact pressure pco (t) = mBP
    the operating point (setpoint) has been found. For this purpose, the contact pressure pc (t) - in this example using a ramp function - was changed and the associated plethysmographic signal v (t) was determined. It can be seen that v (t) has a pulsatile component as well as a kind of "constant component". The pulsatile component arises from the arterial blood pressure fluctuations and its frequency naturally corresponds to the heart rate. The so-called constant component, on the other hand, comes from the absorption of light by bones and skin , Tissue as well as the venous blood, the interstitial fluid and also by the degree of filling of the artery (s). The venous blood and the interstitial fluid can be displaced by the contact pressure pc (t), so the proportion of these proportions also changes with the contact pressure pc (t). The constant component also changes particularly significantly
    by compressing the artery (s) in the extremity such as the finger.
    In order to determine the pulsatile component from v (t), the signal is filtered with a high pass. From a mathematical point of view, this process is simply the same as finding the first derivative with respect to time. As the pressure pc (t) rises, the amplitudes of the pulses initially increase in order to decrease again from a certain pressure - as described above from the mean arterial blood pressure mBP or at the point pco (t). The amplitudes of the pulses behave according to a bell curve. The result is a typical image of the "oscillometric envelope" ", as it is also the case with automatic intermittent ones
    Blood pressure monitors is known.
    The constant component is smallest at low contact pressure pc (t), because the light is absorbed not only by bones, skin and tissue, venous blood and the interstitial fluid, but also by the arterial blood, which is averaged over the pulsations in the artery is located. With increasing pressure, the constant component also increases and with a contact pressure pc (t) well above the systolic blood pressure sBP, the arterial blood is completely displaced from the artery and saturation occurs. The light is only left by bones, skin and
    Absorbs tissue. The constant component reaches a maximum.
    The same p-v diagram is shown in more detail in FIG. 4b. The constant component of v (t) was determined and it can be seen that this corresponds to an S-curve. This S-curve-shaped constant component can also be determined by mathematically integrating the bell-shaped curve
    Determine the "oscillometric envelope". The maximum slope of the S-curve corresponds to Cmax
    the maximum amplitude or the height of the bell curve.
    The searched comparator function for the finger essentially corresponds to the curve-shaped profile of the constant component. The first derivative of this comparator function also corresponds to the oscillometric bell curve from the distribution of the pulse amplitudes. As shown in FIG. 4b, the extreme values Vmin (constant component if pc (t) = 0) and Vmax (constant component if pc (t) >> sBP) as well as the can be used for the parameterization of the S curve in a present variant of the comparator function Working point at Vo / pco (t) = mBP can be used. The slope at the point of the working point corresponds to Cmax
    Figure 4b.
    The following system of equations for the comparator function can be set up:
    max - (pc () - paC)) v (t) - Venin + (Vo - Venin) eVo7V cmaz c A
    V, ax (Vanax - Vo) e Vor
    Vpc (t) <pa) Vpc (t)> pa)
    (2)
    - (pcO- pA (6))
    In this case, the slope k behaves as follows:
    Kt) = 2) Cmax * 7 Ymin PO PAC V pc) <paC) (t) = ap = (3)
    MIX n (t) -pa (t) m (®c 7PA®) Vpc (t)> Dal)
    Cmax ‘€ Vo7V According to the invention, other S-curve functions can also be used, such as
    e.g. the hyperbolic area (arsinh) or the Gaussian distribution or sum function
    ©, which can be used in suitable variants of these functions.
    In further design variants, the comparator function can be determined from other mathematical methods. E.g. the measurement of the v (t) amplitudes at different contact pressures pc (t), whereby these v (t) amplitudes can then serve as support points for any type of empirical functions. The different v (t) amplitudes at different contact pressures pc (t) can be used in an open-loop phase at the beginning of the
    Measurement can be determined.
    Experiments have shown that it is also advantageous to map further physiological properties of the comparator function. As described above, the constant component of v (t) is also dependent on the venous blood and the interstitial fluid, because both components are also dependent on the contact pressure pc (t). The portions of the venous blood disappear relatively quickly when the contact pressure rises above the venous blood pressure - ie to pc (t) >> 20 mmHg - where
    yes also the operating pressure of CNAP devices is usually.
    The case is different for the proportion of interstitial fluid. Firstly, pulsatile changes in pc (t) produce a constant squeezing out and sucking in of interstitial cells
    Liquid in the measuring finger. This has such an effect on v (t) that a hysteresis forms.
    This hysteresis can be represented mathematically as follows:
    . k (t) + Apc @ -pa0) (4)
    Vnpys (CD) = v (t) - Chys dt
    where vhys (t) is the plethysmographic signal with hysteresis and cms is a constant characteristic of the hysteresis. v (t) is the plethysmographic signal that comes from a
    determined using the methods described above; k (t) is the first derivative dv (t) / dt.
    Second, experience has shown that it takes up to five minutes for the interstitial fluid to be pressed out of the finger until a stable equilibrium is established. As long as the constant component drifts due to the interstitial fluid component, there is a kind of parallel shift of the S-curve-shaped comparator function. Such "fluid shifts" can also occur repeatedly during operation, for example due to repositioning of the measuring finger or after the patient has absorbed liquid by drinking, but also by infusions.Therefore, it is advantageous to check the S curve or its parameters at regular intervals The vasomotor system also influences the S-curve
    Comparator function, which makes a check and, if necessary, a correction useful.
    To check and, if necessary, correct the comparator function during operation, the determination of v (t) amplitudes at different contact pressures pc (t) in a short open-loop phase, but also evaluation sequences during the closed-loop phase
    imaginable.
    If the S-curve-shaped comparator function is available and if this is also regularly checked and, if necessary, corrected according to an embodiment variant, the control loop of the present simulator can be closed as described in FIG. This control loop is summarized as follows: an arterial blood pressure curve pa (t) is stored on a storage medium 211. This is read out and fed in the correct chronological sequence to the simulation module 210, in which the S-curve-shaped comparator function is mapped. Furthermore, the contact pressure pc (t) is an input variable of the simulation module 210. The output signal of the simulation module 210 is the plethysmographic signal v (t) with which the light source 203 is now modulated. The light flows through the finger dummy 201 and hits the light sensor 204. This light sensor 204 cannot distinguish whether that is at
    incoming signal v (t) was modulated by absorption in a finger, or by
    the simulation module. The signal v (t) is fed to the regulating mechanism 206, the control value u (t) is determined, and subsequently the contact pressure pc (t) - whichever is changed
    in turn acts on the finger dummy 201. The signal pc (t) is also fed to the simulation module 210, where it is again matched with the arterial on the storage medium 211
    Blood pressure curve pa (t) is compared.
    Nota bene: the simulation module 210 of this embodiment variant generates analog signals: both the light is modulated and thereby a signal v (t) is generated, and the contact pressure pc (t) is also in the blood pressure measuring system 202, for example in the finger cuff 205
    effective.
    In other design variants, the control loop can also be digitally simulated on a computer. Certain electronic elements such as the plethysmographic system 203, 204 or the means for changing the contact pressure pc (t) can be digitally simulated. This has the advantage that other important digital elements such as the control mechanism 206, which is mainly in the form of an algorithm in software
    Codes available can easily be tested on a computer.
    Figures 5a to 5d describe possible methods for validation. It must first be mentioned that the test systems and simulators described here can only be used efficiently for validation purposes if the functionality of the test systems and simulators can also be validated. It must be demonstrated that the
    Systems work with sufficient accuracy.
    For medical technology devices in general and for blood pressure measuring devices in particular, standards apply that have specified tolerance limits. These tolerance limits must be met by new devices versus gold standard methods when they are brought to market. E.g. for intermittent blood pressure monitors a mean difference to the gold standard of 5 mmHg and a standard deviation of 8 mmHg. For continuous
    Blood pressure monitors are currently working on their own standard.
    In order to provide evidence that the present test system also complies with this standard and the tolerance limit, the following procedure could be used: When recording
    a blood pressure curve, which can later be imported into a CNAP simulator system
    the true intra-arterial blood pressure (IBP) should be recorded simultaneously using a catheter (gold standard) and a non-invasive blood pressure curve (CNAP). Ideally, blood pressure curves should not only be recorded for one patient, but also for a certain number of patients, as specified in the norm. The statistical analysis shows a discrepancy between CNAP and the gold standard
    IBP, which ideally comes to lie within the prescribed tolerance limit.
    It is precisely this CNAP system used for recording, including all associated components, that is now being converted into a simulator. The comparator function of the respective patient is imported into the simulation module 210 and the first simulator recording is generated with the associated IBP — referred to as "1% SIMU" in FIGS. 5a-d. This is done for all patient files and a data set of 1 * SIMUSs is created. This data set can now be compared with both the IBP data set and the CNAP data set. The sum of the data records to one another must - as shown in FIG. 5a - lie within a tolerance triangle with the side length "Max. Limit", "Max. Limit" describing the tolerance limit prescribed in a standard. FIG. 5b shows a representation for an acceptable, validated simulator system which is located within the tolerance triangle. All three data sets - IBP (Gold Standard), CNAP and 1% SIMU - have differences between themselves that are within the tolerance limits. In Figure 5c this is not the case
    Case, because here e.g. the deviation between IBP and 1 ° SIMU is too great.
    Although exactly the same CNAP components (sensors, light system, control system, pressing device, etc.) are used for the first simulations, the 1% SIMU blood pressure curve will not be completely equivalent to the CNAP curve. This is the case because the comparator function of the simulation module 210 was only simulated, of course. The better the correlation between CNAP and 1 * SIMU, the more precise the S-curve shape became
    Comparator function simulated.
    The test system is not built to test the same CNAP components afterwards. FIG. 5d now shows how new CNAP systems or subsystems can be tested and, above all, which tolerance limits must be adhered to for validations. If a new data set with new CNAP components is generated by again importing IBP as the gold standard into the simulator with the new CNAP components, then
    the new data system must be used for all three data sets - IBP (gold standard), CNAP as well
    15 SIMU differences within the tolerance limit. In other words, the new SIMU data set must lie within a tetrahedron which, according to FIG. 5d, is above the one from FIG
    5a known "tolerance triangle" with the side length "Max. Limit" spans.
    权利要求:
    Claims (1)
    [1]
    PATENT CLAIMS
    1. A method for validating a continuously measuring, non-invasive blood pressure measuring system (202) which is equipped with a plethysmographic system (203, 204) which is suitable - in a measuring phase - a plethysmographic signal v (t)
    to win an extremity (101),
    e * where the signal v (t) from the plethysmographic system (203, 204) is fed to a control mechanism (206), which via a control value u (t) den
    Contact pressure pc (t) of the blood pressure measuring system (202) on the extremity (101) changed,
    e where based on the resulting contact pressure pc (t) the course of the arterial
    Blood pressure pa (t) is continuously determined,
    characterized,
    ®e that - in a validation or test phase - a signal derived from a previously recorded blood pressure curve via a coupling interface (209) into the
    Blood pressure measuring system (202) is fed.
    2. The method according to claim 1, characterized in that the coupling interface (209) is supplied with an output signal from a simulation module (210), to which a blood pressure profile recorded on a storage medium (211) and the contact pressure pc (t) of the blood pressure measuring system (202) as Input signals are supplied, with a simulated, continuous blood pressure curve by the blood pressure measuring system (202)
    is determined.
    3. The method according to claim 2, characterized in that the simulated, continuous blood pressure curve is compared with the blood pressure curve coupled into the simulation module (210) from the storage medium (211) and differences between the stored and the simulated blood pressure curve as a criterion for
    Validation of the blood pressure measuring system (202) can be used.
    4. The method according to any one of claims 1 to 3, characterized in that the
    previously recorded blood pressure curve for the validation of the blood pressure measuring system (202) from
    an intra-arterial blood pressure measurement (IBP) or a non-invasive blood pressure measurement
    (CNAP) from a previous clinical measurement.
    5. The method according to any one of claims 1 to 4, characterized in that
    ® at the same time as a non-invasive blood pressure measurement (CNAP) on a living being carried out an intra-arterial blood pressure measurement (IBP) on the same living being and
    is recorded;
    e that the recorded intra-arterial blood pressure curve (IBP) and / or the recorded non-invasive blood pressure curve (CNAP) are coupled into the blood pressure measuring system (202) and simulated by the blood pressure measuring system (202)
    Blood pressure curves (SIMU) are generated; and
    e that the simulated blood pressure curves (SIMU) as a criterion for validating the
    Blood pressure measuring system (202) can be used.
    6. The method according to any one of claims 1 to 5, characterized in that the light intensity of the at least one light source (203) of the plethysmographic system - in the validation or test phase - based on the previously recorded blood pressure sale
    is modulated
    7. The method according to any one of claims 1 to 6, characterized in that electronic elements of the blood pressure measuring system (202), such as the plethysmographic system (203, 204), or means for changing the contact pressure pc (t) system - in the validation or test phase - reproduced as a digital software model
    will.
    8. The method according to any one of claims 2 to 6, characterized in that an S-shaped or bell-shaped comparator function in the simulation module (210)
    is calculated.
    9. The method according to claim 8, characterized in that the S-shaped or bell-shaped comparator function before the start of data recording for
    Blood pressure measurement is determined in an open loop phase of the blood pressure measurement system (202).
    10. The method according to claim 9, characterized in that the S-shaped or bell-shaped comparator function during the data recording of the
    Blood pressure measurement is checked and corrected if necessary.
    11. Device for validating a continuously measuring, non-invasive blood pressure measuring system (202) which is equipped with a plethysmographic system (203, 204) which is suitable - in a measuring phase - a plethysmographic signal v (t)
    to win an extremity (101),
    ®e with a control mechanism (206) to which the signal v (t) from the plethysmographic system (203, 204) is fed, which changes the contact pressure pc (t) on the extremity (201) via a control value u (t), and
    ® with an evaluation unit, which based on the resulting contact pressure pc (t)
    the course of the arterial blood pressure pa (t) is continuously determined.
    characterized in that
    e the blood pressure measuring system (202) has a coupling interface (209) via which - in a validation or test phase - a signal derived from a previous
    recorded blood pressure profile can be coupled into the blood pressure measuring system (202).
    12. The device according to claim 11, characterized in that the plethysmographic system (203, 204) has at least one light source (203), preferably an LED, and at least one light detector (204), preferably a photodiode, and that the coupling-in interface (209 ) is suitable based on the light intensity of the light source 203
    to modulate on the signal of the recorded blood pressure curve.
    13. The device according to claim 11 or 12, characterized in that the blood pressure measuring system (202) has a simulation module (210) which is connected on the input side to a storage medium (211) which provides a signal of the previously recorded blood pressure profile pa (t) and on the other hand with a pressure generating device (208) of the plethysmographic system (203, 204), which provides a signal of the contact pressure pc (t), the simulation module (210) being suitable for calculating a comparator function based on the two input signals and sending it to Coupling interface 209
    to submit.
    14. Device according to one of claims 11 to 13, characterized in that the device has a finger dummy (201), which in the validation or test phase of the blood pressure measuring system (202) - instead of the extremity (101) in the measurement phase - in contact with
    the plethysmographic system (203, 204) can be brought.
    15. The device according to claim 14, characterized in that the haptic and / or optical properties of the finger dummy (201) of the extremity (101) of a
    Of living being.
    05/22/2019 LU
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    同族专利:
    公开号 | 公开日
    EP3796834A1|2021-03-31|
    US20210259566A1|2021-08-26|
    AT522324B1|2020-10-15|
    WO2020232492A1|2020-11-26|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US10098554B2|2012-05-31|2018-10-16|Cnsystems Medizintechnik Ag|Method and device for continuous, non-invasive determination of blood pressure|
    WO2017109064A1|2015-12-23|2017-06-29|Koninklijke Philips N.V.|A method of assessing the reliability of a blood pressure measurement and an apparatus for implementing the same|AT524040A4|2020-11-12|2022-02-15|Cnsystems Medizintechnik Gmbh|METHOD AND MEASURING DEVICE FOR THE CONTINUOUS, NON-INVASIVE DETERMINATION OF AT LEAST ONE CARDIAC CIRCULATORY PARAMETER|NL8105381A|1981-11-27|1983-06-16|Tno|METHOD AND APPARATUS FOR CORRECTING THE CUFF PRESSURE IN MEASURING THE BLOOD PRESSURE IN A BODY PART USING A PLETHYSMOGRAPH.|
    AT412702B|2003-10-21|2005-06-27|Cnsystems Medizintechnik Gmbh|DEVICE AND METHOD FOR CONTROLLING THE PRESSURE IN AN INFLATABLE CUFF OF A BLOOD PRESSURE METER|
    US8814800B2|2009-10-29|2014-08-26|Cnsystems Medizintechnik Ag|Apparatus and method for enhancing and analyzing signals from a continuous non-invasive blood pressure device|
    US10285599B2|2015-01-08|2019-05-14|Cnsystems Medizintechnik Ag|Wearable hemodynamic sensor|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50469/2019A|AT522324B1|2019-05-22|2019-05-22|METHOD AND DEVICE FOR VALIDATING A BLOOD PRESSURE MONITORING SYSTEM|ATA50469/2019A| AT522324B1|2019-05-22|2019-05-22|METHOD AND DEVICE FOR VALIDATING A BLOOD PRESSURE MONITORING SYSTEM|
    EP20726286.6A| EP3796834A1|2019-05-22|2020-05-12|Method and device for validating a blood pressure measurement system|
    US17/255,302| US20210259566A1|2019-05-22|2020-05-12|Method and device for validating a blood pressure measurement system|
    PCT/AT2020/060194| WO2020232492A1|2019-05-22|2020-05-12|Method and device for validating a blood pressure measurement system|
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