Automatic filling level monitoring and control method for blood processing machines and air separators using frequency analysis

Abstract

The present invention relates to a blood treatment device (1) for extracorporeal blood treatment, comprising at least one blood conduction system (2), a chamber container (6) for separating bubbles from blood (4) to be treated, and a blood pumping device (8) designed to pump the blood (4) and generate pressure pulses (10) with a predetermined frequency in the blood conduction system (2), the blood treatment device (1) further comprising at least one pressure detection sensor (12) for acquiring the pressure pulses (10) introduced by the blood pumping device (8), a data processing unit (16) designed to derive a filling level parameter (14) from the acquired pressure pulses (10) and to modify the state of an information signal (18) as a function of this parameter, and at least one alarm device (20) activated as a function of the state of the information signal (18). The present invention also relates to a method for monitoring the filling level of blood (4) using the blood treatment device (1) according to the present invention.

Description

[Technical Field]

[0001] The present invention relates to a blood treatment device for extracorporeal blood treatment, comprising at least one blood conduction system / blood line system and at least one chamber container for separating air bubbles from the blood to be treated, the blood treatment device being configured to pump blood and generate pressure pulses with a predetermined frequency in the blood conduction system.Furthermore, the present invention relates to a method for monitoring the blood filling level in the blood treatment device. [Background technology]

[0002] Extracorporeal blood processing machines have long been known in the prior art. For example, International Publication No. WO93 / 01858 discloses a blood processing machine having a controller that outputs a signal to close a venous tubing clamp when air / gas is detected in the venous portion of an extracorporeal blood circuit. The air is removed from the venous portion by inserting a sterile syringe into the vent line of the filter in the air collection chamber and opening the vent line valve to aspirate the air.

[0003] Furthermore, U.S. Patent No. 9,795,731 discloses an extracorporeal blood treatment machine with a control unit, which removes air from the venous portion of the extracorporeal blood circuit via a blood pump.

[0004] Also, International Publication No. WO 2006 / 122737, known as a prior art, discloses a method for filling the blood side of a hemodialysis machine with a physiological electrolyte solution without introducing air. Additionally, U.S. Patent Publication No. 20133 / 0049974, known as a prior art, discloses early detection of low bicarbonate levels. Furthermore, International Publication No. 2015 / 188154, known as a prior art, discloses a system for calculating fluid changes in a pump chamber.

[0005] It is generally necessary to degas extracorporeal blood before returning it to the patient from the extracorporeal blood circuit. That is, if air is present in the venous part of the extracorporeal blood circuit, this is generally a dangerous situation for the patient. Therefore, it is known from the prior art that the air present in the venous part of the extracorporeal blood circuit must be removed and only after this removal can blood therapy be continued.

[0006] Therefore, the air separator is typically installed in the venous line portion of an extracorporeal blood conduction system. It typically has a chamber that is filled with blood to a certain filling height, leaving a cavity above the blood level / gauge formed in this way, from which the air contained in the blood can be released and vented through an outlet. It is also well known that this release process lowers the fill level gauge or blood level in the chamber, respectively, so that the opening of the blood supply port in the chamber is positioned above the lowered blood level / gauge. This can subsequently result in the generation of air bubbles or foam in the air separator chamber as a result of the blood dripping, impairing or causing a malfunction of the actual air separation function and subsequently triggering an alarm in a microbubble detector downstream of the chamber. To solve this problem, it is also known in the prior art to use a gauge detector that monitors the current gauge level in the air separator so that the opening of the blood supply port is below the blood level / gauge.

[0007] However, the devices disclosed in the prior art have the drawback that removing / separating / degassing air from blood present in an IV line section is relatively complicated and inconvenient, which makes them difficult to use. Furthermore, the known prior art uses a number of specific sensors, such as sophisticated air detectors to detect whether air that may be dangerous to the patient is present in the system, and fill level sensors to detect whether the fill level of the air separator chamber is sufficient. This makes the entire sensor system complex and expensive. Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to avoid or at least reduce the disadvantages of the prior art, particularly in blood processing machines where the design allows for easy estimation of the gauge level in the venous chamber.

[0009] The core idea of the present invention essentially consists in that the blood treatment device further comprises at least one pressure detection sensor for detecting pressure pulses introduced by the blood pumping device, a data processing unit adapted / designed to derive a filling level parameter from the detected pressure pulses and to change the state of the notification signal as a function thereof, and at least one alarm device activated as a function / depending on the state of the notification signal.

[0010] Therefore, the pressure pulses generated by the blood pump / blood pumping device when transporting blood into the extracorporeal blood circuit and input into the transported blood are utilized / used to determine or, respectively, estimate the current filling level.

[0011] Here, the technical effect is used that these (inevitable) pressure pulses in the air separator chamber vary depending on the current filling level and the resulting current air cushion volume above the blood gauge / level in the air separator. The change(s) detectable by this / these sensors, e.g. changes in pulse amplitude, allow (continuous) conclusions to be drawn about the current filling level.

[0012] In other words, this object is solved by a universal blood treatment device in that the blood treatment device comprises at least one pressure detection sensor, which is provided for detecting the blood pressure generated by the blood pump / blood pumping device of the treatment device in the venous blood conduction system in general, and in the air separator chamber in particular. According to the invention, the pressure detection sensor is indeed (additionally) utilized / used for detecting at least one filling level parameter of the pressure pulse introduced by the blood pumping device, a data processing unit is provided which is designed and arranged to change the state of a notification signal or a warning signal to a relevant state depending on the at least one filling level parameter of the pressure pulse detected by the detection sensor, and for this purpose an alarm device is provided which is activated in the event of the relevant state of the notification signal.

[0013] Thus, in a first embodiment, the notification signal can assume an associated and an unassociated state, i.e., it is switchable between two binary states. In a further embodiment, the notification signal is continuously variable, i.e., it can change its state slowly, i.e., continuously.

[0014] The extracorporeal blood treatment device advantageously comprises a pressure detection sensor designed / adapted to indirectly measure the filling level of the chamber container / air separator chamber. For this purpose, the pressure detection sensor detects a filling level parameter representing the gauge level of the chamber container. In a further advantageous embodiment, the blood treatment device according to the present invention further comprises a data processing unit which sets the state of a notification signal to an associated or inassociated state depending on the detected filling level parameter. The additional alarm device is set to an activated or deactivated state by the notification signal. For this reason, the blood treatment device is not provided with any other sensors for detecting the level in the air separator, except for the pressure detection sensor (which may be present anyway). In an advantageous embodiment, the blood pumping device, which is necessarily required to pump blood through the dialysis device, is also used to restore the filling level in the chamber container in the event of a pressure drop. For this reason, it is necessary to automatically open the chamber vent so that excess air can be expelled in a targeted manner. Prior art devices include roller pumps that can remove or add air to adjust the gauge, as well as small "compressors" that provide overpressure and valves for air release.

[0015] In a preferred embodiment, the at least one filling level parameter includes at least the pressure pulse amplitude and / or pressure pulse width of the pressure pulse detected by the pressure detection sensor. By determining the pressure pulse amplitude or the respective pressure pulse width of the pressure pulse detected by the pressure detection sensor, the damping present in the system (which is influenced by the air cushion volume in the air separator) can be advantageously determined, and thereby the filling level of the air separator or the amount of air present in the air separator / chamber container can be indirectly determined. The pressure pulse amplitude and / or pressure pulse width are characteristic values that describe the pressure pulse.

[0016] In a further preferred embodiment, the data processing unit is configured to perform a frequency analysis, preferably via a Fourier transform, to determine the pressure pulse amplitude (hereinafter referred to only as pressure amplitude) and pressure pulse width (hereinafter referred to only as pressure width) from the pressure pulse. In this frequency analysis, a periodic function is divided into a sum of angular functions. The period of a simple harmonic motion or each harmonic is then an integer multiple of the fundamental vibration with that period and angular frequency. The amplitudes of these vibrations are called Fourier coefficients. From a mathematical point of view, this is a series expansion. This method advantageously makes it possible to represent the measured signal in terms of individual frequency components and obtain a frequency spectrum. By transforming sine or cosine components of the same frequency into polar coordinates, the amplitude and phase spectra are obtained.

[0017]

[0010] Furthermore, preferably, the filling level parameter represents an indicator of the blood filling level in the chamber container, and the data processing unit is adapted to change the notification signal to a relevant state as soon as the filling level parameter falls below a predetermined filling level threshold. By determining the filling level parameter, the pressure amplitude and pressure width of the pressure pulse detected by the pressure detection sensor are determined, and the volume of air in the chamber container is thereby estimated via damping. If the filling level parameter falls below the predetermined filling level threshold, i.e., if the gauge of the chamber container falls below a defined mark, the notification signal is set to a relevant, i.e., critical, state.

[0018] In a further embodiment, the data processing unit is further adapted to change the alarm signal to an associated state and activate at least the alarm device as soon as a predetermined occurrence threshold is exceeded, which defines how often the fill level of the blood in the chamber falls below the fill level threshold in a predetermined time. Advantageously, the blood pumping device is driven to increase the blood gauge in the chamber as soon as the blood gauge in the chamber falls below the fill level threshold. In this way, the advantage is achieved that no air bubbles are introduced into the blood conduction system.

[0019] More preferably, the pressure detection sensor has a sampling rate of at least 100 Hz to detect blood pressure pulses over time, and is preferably a conventional venous pressure sensor that detects pressure in the blood line system via a Transducer Protector Filter (TP) or indirectly via a POD.

[0020] In a further advantageous embodiment, the blood pumping device further comprises a gauge adjustment pump and / or a level adjustment pump, whereby a pump is provided which is configured to keep the level or gauge, respectively, in the blood conduction system or in the chamber container constant, so that the gauge does not fall below a critical value.

[0021] Furthermore, advantageously, a method for monitoring the blood filling level in a blood processing device according to the present invention is claimed, which method comprises the steps of detecting pressure pulses introduced by a blood pumping device by a pressure detection sensor, deriving a filling level parameter from the pressure pulses detected by the pressure detection sensor, continuously analyzing and processing the detected filling level parameter by a data processing unit, changing the state of a notification signal depending on the filling level parameter as soon as the filling level parameter falls below a predetermined filling level threshold, and activating an alarm device depending on the state of the notification signal.

[0022] The basic idea of the device according to the invention is to estimate the air volume in the chamber via the determined damping, which changes if bubbles or air are present in the blood conduction system or the chamber. Therefore, in an advantageous embodiment, no additional filling level sensor is required, but since pressure pulses are present in the blood conduction system of the blood treatment device anyway, the detected filling level parameter is determined indirectly by evaluating the pressure pulses of the blood pumping device. Thus, the amount of bubbles is also detected and determined.

[0023] A further advantageous method step claims that the pressure amplitude and / or pressure width is continuously determined from the pressure pulses via frequency analysis by the data processing unit, for which the data processing unit is a continuously operating processor in combination with a memory unit, which continuously acquires the provided data, parameters, reference values and predefined thresholds, evaluates and assesses them and provides them to other units, for example an alarm device.

[0024] Further advantageously, the method includes the steps of: - changing the notification signal to an associated state as soon as the filling level parameter falls below a predetermined filling level threshold; - generating a drive signal in the event of the associated state of the notification signal; and - driving the blood pumping device so that the filling level of blood in the chamber container increases as soon as the predetermined filling level is undershot / falls below.

[0025] As soon as the fill level threshold, i.e., the gauge level of blood in the chamber, falls below a predetermined fill level threshold, i.e., a predetermined threshold below which the gauge of blood may be dangerous to the patient, a notification signal is generated by the data processor. From this notification signal, the data processor in turn generates drive signals to drive the blood pumping device and the gauge adaptation device to increase the fill level of blood in the chamber, thereby avoiding the risk of air getting into the patient's blood and causing damage. Overall, the method according to the invention thus provides a control method that continuously ensures that there is enough blood in the blood conduction system and the chamber, but not enough air, with a high gauge level so that the patient is continuously supplied with enough blood.

[0026] Further advantageously, the method comprises the step of activating a gauge and / or level adjustment pump and a vent of the chamber container when a predetermined filling level threshold is undershot, the gauge and / or level adjustment pump being additionally designed to maintain the filling level in the chamber container at a predetermined gauge and / or level, and opening the vent to expel excess air and vent the entire blood circuit.

[0027] In a further advantageous embodiment, the method comprises the steps of: - changing the state of the alarm signal to an associated state as soon as the fill level threshold exceeds a predetermined trigger threshold; and - in the case of the associated state of the alarm signal, activating an alarm device.

[0028] If the system is forced to adjust the blood filling level frequently, i.e., if air is frequently present in the blood, an alarm signal is triggered and the alarm device is activated. In this case, the system is affected by a leak, electrical short, or other technical problem and a qualified person must be notified. If air is detected in the blood conduction system, the data processor stops the blood pump and issues an alarm signal via the alarm device.

[0029] In other words, the invention relates to a dialysis machine equipped with a pressure sensor, which measures with high resolution the pressure curve that determines the pressure in the chamber. The frequency is chosen so that the pressure pulses generated by the peristaltic movement of the blood pump have good resolution. The pressure pulses, pressure height, pressure width and pressure decay are determined by frequency analysis, in particular by Fourier transformation. A small volume means that the chamber is full, which in turn means higher frequency components, i.e. higher and shorter pulses. A large volume means that the chamber is empty, i.e. the fundamental component of the frequency is high and the signal is more attenuated and delayed. The reference value is either permanently stored or is only (fully) defined after filling.

[0030] If the deviation is greater than X, i.e., if the spectrum and amplitude change beyond a certain limit, an alarm is triggered before the chamber is completely emptied. Alternatively, the gauge can be automatically recalibrated. If this recalibration is performed too frequently, an alarm will also be triggered due to air being drawn in somewhere, a leak in the system, or damage, respectively. Another alternative is to introduce a constant, known amount of air via a gauge-increasing or gauge-decreasing connection to an existing blood pump or a closed venous clamp. The resulting pressure increase can be used to directly determine the volume of air in the chamber. This can be done using a gauge-increasing or -decreasing device with a pump. It is also possible to detect specific blood lines, as the spectrum changes depending on the chamber size and material.

[0031] The pressure sensor is a conventional venous pressure sensor that records the pressure in the venous line indirectly via a transducer protector filter (TP) or via a POD. The sampling rate of the sensor needs to be in the range of approximately 100 Hz to resolve the pulses accurately enough.

[0032] The bubble detection step of the method is performed to estimate the volume of air in the chamber via attenuation, since bubbles behave differently than pure blood or have different attenuation coefficients.

[0033] Preferably, the data processing unit is adapted to determine the pressure pulse decay from the detected pressure pulses as a further filling level parameter and compare it with an associated reference value stored in the data processing unit.

[0034] According to a further preferred embodiment, the maximum pressure pulse width and / or the minimum pressure pulse amplitude can be stored as reference values, or alternatively, the minimum pressure pulse width and / or the maximum pressure pulse amplitude can be stored, and if this minimum value is compared and undershot and / or this maximum value is exceeded, the data processing unit changes the state of the notification signal accordingly. Thus, for example, the maximum pressure pulse width can function as a threshold value, and if this threshold value is exceeded, the data processing unit recognizes and determines that the fill level height is too low. For example, since a high fill level height of blood in the chamber has a smaller pressure pulse width than a low fill level height, if a predetermined threshold is exceeded or undershot, a relevant fill level, in particular a relevant lower fill level limit for safe operation of the infusion tank, can be inferred based on the relevant fill level parameter.

[0035] Preferably, the data processing unit may further be adapted to change the state of the notification signal and activate at least an alarm device as soon as a predetermined occurrence threshold is exceeded, which defines how often the fill level of the blood in the chamber container falls below the fill level threshold in a predetermined time.

[0036] There are various definitions of (pressure) pulse width. One definition of pulse width is the time of the pulse between 50% of the rising and falling edges of the pulse. The 50% value, Full Width at Half Maximum (FWHM), refers to the maximum amplitude of the pulse. Another definition of pulse width is 90% of the maximum amplitude, or 1 / e where e = 2.718.

[0037] The amplitude of a frequency is the amplitude of a frequency in a frequency spectrum. The amplitude of a frequency range is the amplitude within a predetermined frequency range, such as from a particular minimum frequency to a particular maximum frequency.

[0038] In other words, a method for monitoring the blood filling level in a blood processing device may particularly include the steps of detecting pressure pulses introduced by a blood pumping device by a pressure detection sensor, deriving a filling level parameter from the pressure pulses detected by the pressure detection sensor, continuously analyzing and processing the detected filling level parameter by a data processing unit, changing the state of a notification signal depending on the filling level parameter as soon as the filling level parameter falls below a predetermined filling level threshold, and activating an alarm device depending on the state of the notification signal.

[0039] According to one embodiment, the method may include the steps of changing a notification signal to an associated state as soon as the filling level parameter falls below a predetermined filling level threshold, generating a drive signal in the event of the associated state of the notification signal, and driving a blood pumping device so that the filling level of blood in the chamber container increases as soon as the filling level falls below the predetermined filling level threshold.

[0040] Preferably, the method may comprise the step of activating the gauge adjustment pump and / or the level adjustment pump and the vent of the chamber container when the fill level falls below a predetermined fill level threshold.

[0041] The present invention will now be further described with reference to the following drawings, in which: [Brief explanation of the drawings]

[0042] [Figure 1] 1 shows a blood processing device according to the present invention with the chamber container in a nearly full state. [Figure 2] 1 shows a blood processing device according to the present invention with the chamber container in a nearly empty state. [Figure 3] The input and output parameters of the frequency analysis method are outlined in the partial views of Figures 3a, 3b and 3c. [Figure 4] An overview of the input and output parameters of the frequency analysis method is shown in the partial diagrams of Figures 4a and 4b. [Figure 5] 1 shows various frequency spectra representing the corresponding fill levels of each chamber vessel. [Figure 6] The thresholds and parameters processed in the data processing unit and the signals sent to the respective output devices are shown. DETAILED DESCRIPTION OF THE INVENTION

[0043] FIG. 1 shows a blood treatment device 1 including a blood conduction system 2 having blood 4 in its chamber 6. It can be clearly seen that the chamber 6 is filled with blood 4 to approximately three-quarters of its maximum filling level. Furthermore, the blood treatment device 1 includes a blood pumping device 8, preferably a peristaltic pump, for circulating the blood 4 within the blood conduction system 2. It can also be seen that a pressure detection sensor 12 is integrated into the blood conduction system 2. However, the pressure detection sensor 12 may also be provided in the chamber 6. It can also be seen that there is an input 32 of the chamber 6 and an output 34 of the blood conduction system 2. In the illustrated blood treatment device 1, the pressure detection sensor 12 is shown connected to a data processing unit 16 in a signal-conducting manner. This signal conduction is bidirectional, i.e., the pressure detection sensor 12 sends a detected signal to the data processing unit 16, and the data processing unit 16 can also send a signal back to the pressure detection sensor 12. It can also be seen that both the blood pumping device 8 and the alarm device 20 are connected to the data processing unit 16 in a signal-conducting manner. In either case, signal conduction may be unidirectional or bidirectional.The alarm device 20 may also be designed, for example, as a mobile communication device, for example a tablet and / or a mobile phone.

[0044] 2 shows another state of the blood processing device 1, in which the chamber container 6 is nearly empty and not filled with blood 4. Again, the blood pumping device 8 and the pressure detection sensor 12 are visible, which are integrated into the blood conduction system 3. The blood conduction system 2 again has an input 32 and an output 34. Also shown in FIG. 2 are signal-conducting connections between the data processing unit 16 and the blood pumping device 8, the pressure detection sensor 12, and the alarm device 20. The blood pumping device 8 may further include a gauge adjustment pump and / or a level adjustment pump 42 specifically designed to maintain the filling level at a predetermined level.

[0045] FIG. 3 is divided into individual figures 3a, 3b, and 3c. FIG. 3a shows the time-dependent pressure curve of a pressure pulse 10 supplied from the blood pumping device 8 or an additional pressure pulse source. The additional pressure pulse source can be, for example, external. FIG. 3b shows the pressure pulse 10 measured by the pressure detection sensor 12 and processed by the data processing unit 16. The measured pressure pulse 10 has a pressure amplitude 36 and a pressure width 38. FIG. 3c shows a frequency spectrum plotted with the pressure amplitude 36 on the vertical axis and the frequency 40 on the horizontal axis. Figures 3b and 3c show examples where the pressure pulse 10 is "sharp" and has a large pressure amplitude 36, completely filling the chamber. This is also evident at the high pressure amplitude 36 in the frequency spectrum.

[0046] Figure 4 is divided into Figures 4a and 4b. Figure 4a shows a pressure pulse 10 measured by pressure detection sensor 12, which has a wide pressure pulse 38 with a small pressure amplitude 36. The measured pressure pulse is represented by the frequency spectrum shown in Figure 4b, where again the pressure amplitude 36 is shown on the vertical axis and the frequency f is shown on the horizontal axis.

[0047] FIG. 5 shows three different filling states of the chamber 6. In the first filling state, the chamber 6 is completely filled with blood 4. This is associated with a frequency spectrum above, again showing the pressure amplitude 36 on the vertical axis and the frequency 40 on the horizontal axis. It can be seen that the pressure amplitude 36 in the first frequency spectrum is very prominent and slowly decreases with increasing frequency 40, i.e., with the frequency spectrum further to the left. In the intermediate filling state, the chamber 6 is about half-filled with blood 4, while the chamber 6 on the right is bloodless. Again, it can be seen that in the intermediate filling state, the pressure amplitude 36 is already less prominent than in the fully filled state shown on the left. In the completely emptied state shown on the far right, the pressure amplitude 36 is even less prominent. It is therefore clear that the frequency spectrum allows for unambiguous assignment of each filling state of the chamber 6.

[0048] 6 shows a data processing unit 16 that receives the filling level parameter 14 from the pressure detection sensor 12. The data processing unit 16 processes the received filling level parameter 14 into a notification signal 18 that is set to an activated or deactivated state, respectively, taking into account a filling level threshold 22, and into an alarm signal 26 that can be set to an activated or deactivated state and activate an alarm device 20. Furthermore, the data processing unit 16 is provided with a triggering threshold 28, which defines how often the blood pumping device 8 can refill the chamber container 6 to ensure that it is intact and leak-free. If the triggering threshold 28 is exceeded, the alarm signal 26 is output, activating the alarm device 20. If the filling level of the chamber container / air separator falls below the triggering threshold 22, a control signal 24 is generated, which is adapted to activate the pumping device 8 to refill the chamber container 6 with blood 4.

[0049] Below we describe the method steps required to recognize in detail how the frequency spectrum changes depending on the size and material of the chamber (this is also known as the recognition of different "blood lines").

[0050] The basic idea behind the method of the present invention is to close the venous clamp before priming, i.e., when there is only air in the line, and then pump a constant volume of air through the blood pump. For this purpose, the blood pumping device (pump) can be preset to a position that allows it to pump a known volume of blood, for example, exactly one revolution. In this case, the starting position of the roller is still locked on the pump output side. The volume of blood pumped is approximately 10–15 ml per revolution, depending on the blood pumping device. The combined volume of the venous chamber (20–40 ml), dialyzer (80–120 ml), and tubing (approximately 10 ml) is approximately 110–170 ml. For known dialyzers, the chamber volume can be calculated from the pressure increase, and for known blood conduction systems, the blood-side filling volume of the dialyzer can be calculated. This is based on the application of the ideal gas equation, which is (pressure × volume) / temperature = constant, or mathematically expressed as Px × V / Temp = constant. The total volume of the dialyzer and chamber must be determined, and from this value the priming volume can then be determined and optimized. The determined volume, taking into account the remaining tubing, is typically 4 x 25 ml / m = 100 ml / m + determined volume of the chamber and dialyzer. Using the nomenclature and assumptions below, the formulas listed below apply:

[0051] Vk = chamber volume, Vd = dialyzer volume, VL = air bolus to increase pressure, P = pressure at each volume. Assumption: Ignore volume in the tubing.

[0052] The following instrument formula is used: P1×(V1+VL) / T=P2×(V1) / T V1=Vd+Vk+VL P1V1+P1VL=P2V1 (Here, the assumptions are that the temperature is constant and V1+VL is compressed to V1) P1VL=P2V1-P1V1 P1VL / V1=P2-P1 V1=P1VL(P2-P1) Vd+Vk+VL=P1VL / (P2-P1) Vk=P1VL / (P2-P1)-Vd-VL

[0053] Additionally, the processing device 1 may have the following monitoring functions, device features, or states:

[0054] Filling level monitoring of an air separator of a dialysis machine, device for determining the filling level of an air separator via a pressure curve, device for determining the pressure curve of an artery or a respective vein, method for determining the filling level of an air separator, method for determining the pressure curve of an artery or a respective vein, determination of the filling level by frequency analysis of the pressure curve, determination of the filling level by introducing a certain amount of air or liquid and evaluating the pressure increase, introduction of air via a gauge increase / decrease connection with an erected blood pump and a closed SAKV, introduction of air or liquid via a blood pump with a closed SAKV, comparison of the pressure curve with a reference state, saving the reference state as a fixed value, determining the reference state in the filling state, alarm in case of specific deviations from the reference state, automatic readjustment of the filling state in case of deviations from the reference state, alarm if the filling state is readjusted too frequently, device for detecting bubbles in an air separator, device for determining the amount of bubbles and blood, method for detecting bubbles in an air separator, method for determining the amount of bubbles in blood and / or detection device for the blood tubing system used. [Explanation of symbols]

[0055] 1) Blood Processing Device 2) Blood Conduction System 4) Blood 6) Chamber container 8) The blood pumping device 10) Pressure pulse 12) Pressure detection sensor 14) Filling level parameters 16) The data processing section 18) Notification signal 20) The alarm device 22) Filling level threshold 24) The drive signal 26) The alarm signal 28) Threshold of occurrence 30) Dialysis machine 32) Input 34) Output 36) Pressure amplitude 38) Pressure range 40) Frequency 42) Gauge adjusting pump or level adjusting pump

Claims

1. 1. A blood treatment device for extracorporeal blood treatment, comprising: a blood conduction system having a chamber container for separating bubbles from blood to be treated; and a blood pumping device configured to pump blood and generate pressure pulses having a predetermined frequency in the blood conduction system, The blood processing device comprises: a pressure detection sensor in the blood conduction system that detects the pressure pulses introduced by the blood pumping device; a data processing unit adapted to determine from the detected pressure pulses a pressure pulse amplitude and / or a pressure pulse width of the pressure pulses, which serves as a filling level parameter, by performing a frequency analysis method, to compare the pressure pulse width and / or the pressure pulse amplitude of the filling level parameter with at least one reference value stored in a data processing unit, to determine a filling level of the blood in the chamber based on the comparison with the reference value, and to change the state of a notification signal as a function of the filling level parameter and thus the filling level of the blood in the chamber; at least one alarm device activated as a function of said state of said notification signal.

2. the pressure pulse detected after the first filling of the chamber with blood or a predetermined pressure pulse representative of the chamber being completely filled with blood is stored as a reference value in the data processing unit; 2. The blood processing device of claim 1, wherein the data processor changes the state of the notification signal at a predetermined maximum deviation between the pressure pulse width of the detected pressure pulse and the pressure pulse width of the stored reference value and / or at a predetermined maximum deviation between the pressure pulse amplitude of the detected pressure pulse and the pressure pulse amplitude of the reference value.

3. the detected pressure pulse of the chamber vessel at a predetermined fill level threshold is stored as a reference value in the data processing unit, 2. The blood processing device of claim 1, wherein the data processor changes the state of the notification signal in the event of a predetermined minimum deviation or overshoot between the pressure pulse width of the detected pressure pulse and the pressure pulse width of the stored reference value and / or in the event of a predetermined minimum deviation or undershoot between the pressure pulse amplitude of the detected pressure pulse and the pressure pulse amplitude of the reference value.

4. 2. The blood treatment device according to claim 1, wherein the blood treatment device has a pressure detection sensor in its blood conduction system, and by having this pressure detection sensor, the filling level of the blood in the chamber container can be determined.

5. the pressure pulses are stored in the data processing unit in the form of a frequency spectrum as a reference value, or the data processing unit is adapted to convert the pressure pulses stored in the data processing unit into the stored frequency spectrum by the frequency analysis method; 2. The blood treatment device according to claim 1, wherein the data processing unit is adapted to compare the frequency spectrum of the detected pressure pulse with the stored frequency spectrum and to change the state of the notification signal in case of a predetermined minimum deviation and / or a predetermined maximum deviation in a range of frequency amplitudes.

6. at least one predetermined frequency amplitude or range of frequency amplitudes is stored as a reference value; 2. The blood processing apparatus of claim 1, wherein the data processor changes the state of the notification signal when the stored frequency amplitude or range of frequency amplitudes is undershot.

7. the fill level parameter represents an indication of the fill level of the blood in the chamber; 2. The blood treatment device according to claim 1, wherein the data processing unit is adapted to change the notification signal to an associated state as soon as the fill level parameter falls below a predetermined fill level threshold.

8. the data processing unit is further adapted to generate a drive signal in case of a relevant state of the notification signal; 8. The blood processing device of claim 7, wherein the drive signal drives the blood pumping device such that the fill level of the blood in the chamber container increases as soon as the predetermined fill level threshold is undershot.

9. 9. The blood treatment device of claim 8, wherein the data processing unit is further adapted to change an alarm signal to an associated state and activate at least the alarm device as soon as a predetermined occurrence threshold is exceeded, which defines how often the fill level of the blood in the chamber container falls below the fill level threshold in a predetermined time.

10. 2. The blood processing apparatus of claim 1, wherein the pressure detection sensor has a sampling rate of at least 100 Hz for detecting the pressure pulses of the blood over time.

11. the blood pumping device further includes a gauge adjustment pump and / or a level adjustment pump; 10. The blood processing apparatus of claim 1, wherein the chamber container further comprises an actuatable vent for ventilating the chamber container.

12. A method for monitoring the fill level of blood in a blood treatment device according to any one of claims 1 to 11, comprising the steps of: detecting the pressure pulse introduced by the blood pumping device with the pressure detection sensor; the data processing unit determining the pressure pulse amplitude and / or the pressure pulse width of the detected pressure pulse as the filling level parameter by performing the frequency analysis method; the data processing unit comparing the pressure pulse width and / or pressure pulse amplitude of the filling level parameter with at least one reference value stored in the data processing unit; the data processor determining the fill level of the blood in the chamber container based on the comparison with the reference value; said data processing unit continuously analysing and processing said detected fill level parameters; the data processing unit changing the state of the notification signal in dependence on the filling level parameter as soon as the filling level parameter falls below a predetermined filling level threshold; and the data processing unit actuating the alarm device in response to the state of the notification signal.

13. The method of claim 12 , further comprising the step of the data processor continuously determining the pressure pulse amplitude and / or the pressure pulse width from the detected pressure pulses via the frequency analysis method.

14. The method of claim 13, wherein the data processing unit changes the state of an alarm signal to a relevant state as soon as the fill level threshold exceeds a predetermined trigger threshold.

13. The method of claim 12, further comprising the step of: said data processing unit activating said alarm device in the event of a condition associated with said alarm signal.

15. 7. The blood treatment device of claim 6, wherein the frequency amplitude at a predetermined fill level threshold is stored as a reference value.

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