Method and system for determining a coagulation event in an arterial line

Abstract

The present disclosure relates to a method (100), a corresponding system, a computer program product, and a data carrier signal for notifying a coagulation event in an arterial line (1) of a human (2). The method (100) comprises providing a hemodynamic signal indicating an arterial blood pressure waveform (10) in the arterial line (1) (step 110), determining a hemodynamic systolic parameter related to the contraction of the heart based on the hemodynamic signal (step 120), determining a hemodynamic relaxation parameter related to the relaxation of the heart based on the hemodynamic signal (step 130), determining a coagulation event in the arterial line (1) when the hemodynamic systolic parameter indicates a decrease in contractility and the hemodynamic relaxation parameter indicates an increase in contractility (step 140), and providing a signal for notifying the determined coagulation event (step 150).

Description

Technical Field

[0001] The present disclosure relates to a method, a corresponding system, and a corresponding computer program for notifying a coagulation event in a human arterial line.

Background Art

[0002] An arterial line is a small indwelling catheter inserted into a human artery such as the radial artery. Arterial lines are commonly used in critical care. This allows for easy repeated blood sampling without the need to repeatedly stick the patient with a needle, and also allows for continuous assessment of blood pressure, for example, continuously displaying waveforms and / or pressures from the artery on, for example, a bedside monitor. Additionally, other hemodynamic parameters such as stroke volume, cardiac output, systemic vascular resistance (SVR), maximum pressure gradient (maximum dp / dt), and derived parameters such as pulse pressure variation (PPV), stroke volume variation (SVV), or hypotensive prediction index (HPI) developed by Edwards Lifesciences (Irvine, California) are also available.

[0003] Even when using a continuous flushing system to prevent coagulation during measurement with an arterial line, coagulation can occur in the arterial line. The quality of the arterial line and thus the measurement deteriorates. However, it is difficult to recognize the onset or presence of a coagulation event. Usually, even when a coagulation event occurs, blood pressure measurements, such as systolic or diastolic pressure measurements or mean arterial pressure, remain close to the original values within the normal physiological range.

[0004] Due to the magnitude of the blood pressure waveform signal, an anesthesiologist may not be able to easily evaluate the waveform, for example, on the patient monitor screen. Since the pulse pressure gradually decreases, a gentle trend is often seen in, for example, the stroke volume (SV). However, since the decrease in SV may also have another physiological cause, it is often not recognized (in a timely manner) by the anesthesiologist. In applications such as perioperative fluid management, such a gentle decrease in the measured signal can be very misleading and may even cause incorrect diagnoses and unwanted interventions.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, it is an object of the present invention to enhance the safety of a patient during an intervention in which an arterial line is inserted into the patient.

Means for Solving the Problems

[0006] In one aspect, a method for notifying a coagulation event in a human arterial line is proposed. This method includes the step of providing a hemodynamic signal indicative of an arterial blood pressure waveform in the arterial line.

[0007] The hemodynamic signal can be a digital or analog representation of the arterial blood pressure waveform itself. In other examples, the hemodynamic signal can be filtered or processed, for example, averaged over a time much shorter than the duration of the heartbeat, before being provided.

[0008] In some embodiments, the hemodynamic signal is provided substantially in real time during the intervention, that is, while the arterial line is inserted into the patient. In this case, the hemodynamic signal is preferably provided continuously over the entire intervention period or a part thereof. In other examples, the hemodynamic signal is pre-recorded and can thus show the arterial blood pressure waveform of a previous intervention. The hemodynamic signal can be provided in such examples by wired or wireless data transmission supplied from a storage means such as a server.

[0009] The provided hemodynamic signal does not, in the context of the present invention, imply a spatial relationship between the source of the hemodynamic signal and the destination to which it is provided. In some examples, the hemodynamic signal can be provided to a processing device that is in close proximity to the patient. In other examples, the hemodynamic signal can be provided to a processing device, such as a server, that is remote from the patient. Any feasible form of providing the hemodynamic signal is thus contemplated within the context of the present disclosure.

[0010] This method further includes the step of determining a hemodynamic systolic parameter related to the contraction of the heart based on the hemodynamic signal.

[0011] The hemodynamic systolic parameter includes one or a combination of a plurality of individual hemodynamic parameters. The parameter is related to the contraction of the heart when its corresponding feature results from the contraction of the left ventricle that creates the pulse wave. The pulse wave causes a sharp increase in arterial pressure and a sharp increase in the forward flow through the artery.

[0012] This method further includes the step of determining a hemodynamic relaxation parameter related to the relaxation of the heart based on the hemodynamic signal.

[0013] During the relaxation period of the heart, diastolic decline of arterial blood pressure occurs until the next heartbeat initiates a new pulsation. The hemodynamic relaxation parameter includes one or a combination of a plurality of hemodynamic parameters, which can be derived from the relaxation of the heart.

[0014] Both the hemodynamic systolic parameter and the hemodynamic relaxation parameter can be predefined, for example, made static with respect to the operation of the method. In other examples, the hemodynamic systolic parameter and / or the hemodynamic relaxation parameter can change over time, as will be detailed below.

[0015] Thus, in some embodiments, steps or mathematical rules for obtaining hemodynamic contraction parameters and / or hemodynamic relaxation parameters can be provided to determine corresponding parameters. All executable forms known to those skilled in the art for implementing the determination of hemodynamic parameters are contemplated.

[0016] This method further includes the step of determining a coagulation event in the arterial line when the hemodynamic contraction parameter indicates a decrease in contractility and the hemodynamic relaxation parameter indicates an increase in contractility.

[0017] It is an important discovery of the inventors of the present disclosure that an obvious contradiction in the hemodynamic parameters distal to the coagulated artery may indicate the occurrence of a coagulation event in the arterial line. Since the hemodynamic contraction parameter indicates a decrease in contractility and the hemodynamic relaxation parameter indicates an increase in contractility, the two parameters are contradictory to each other. This situation is recognized as the occurrence of a coagulation event according to the present disclosure.

[0018] This method further includes the step of providing a signal to notify the determined coagulation event.

[0019] When a coagulation event is detected, the method anticipates the step of notifying the determined coagulation event. All executable types of notifications are contemplated by the present disclosure. In one example, the signal for notifying the determined coagulation event is a message on a patient monitor or other visually recognizable display, which is generally known to indicate, for example, the pulse pressure wave during life-saving emergency intervention.

[0020] In another example, the signal is notified to a server or another entity and used to generate a visual, audible or other prominent notification to a healthcare provider.

[0021] Accordingly, a signal that notifies of the determined coagulation event can facilitate timely identification of the coagulation event, and the arterial line can be automatically or manually flushed to resolve the detected coagulation.

[0022] In this embodiment, the step of providing a signal that notifies of the determined coagulation event is described as an integral part of the method, but in other embodiments, methods that do not use the notification step can also be beneficial. For example, the result of the determination of the coagulation event can then be further processed.

[0023] In a preferred embodiment, the hemodynamic systolic parameter includes at least one hemodynamic parameter derivable from the arterial blood pressure waveform between the start of systole and the closure of the aortic valve at the end of systole, and the hemodynamic systolic parameter specifically the maximum change in blood pressure during systole, the end-systolic pressure, the area under the arterial blood pressure waveform curve above the end-diastolic pressure between the start of systole and the closure of the aortic valve at the end of systole, includes at least one of.

[0024] Since a pulse wave is created when the left ventricle contracts, the hemodynamic systolic parameter is thus related to the contraction of the heart. This pulse wave causes a rapid rise in arterial pressure and a rapid rise in forward flow through the artery. Any parameter suitable for characterizing the increase in pressure in the artery during systole can thus be part of the hemodynamic systolic parameter according to this embodiment. Further executable parameters include first derivatives, second derivatives, etc. of the above-mentioned parameters, maximum derivatives, etc. It should be noted that the above list of parameters is not complete, and those skilled in the art will understand that additional parameters can be used alone or in combination to obtain the hemodynamic systolic parameter.

[0025] In a preferred embodiment, the hemodynamic relaxation parameter includes at least one of end-diastolic pressure, mean arterial pressure, and interbeat interval.

[0026] Hemodynamic relaxation parameters are thus parameters related to the relaxation period of the arterial blood pressure waveform, during which the arterial blood pressure decreases until the next heartbeat initiates a new pulsation. In other words, all parameters not resulting from the contraction of the left ventricle can be considered parameters related to the relaxation period, which includes the inter-beat interval. Also, with regard to hemodynamic relaxation parameters, additional further parameters are well known to those skilled in the art, and it should be emphasized that all these parameters can be used alone or in combination with further hemodynamic relaxation parameters as the hemodynamic relaxation parameters in this embodiment.

[0027] In a preferred embodiment, at least one of the hemodynamic systolic parameter and the hemodynamic relaxation parameter is determined as an average over a predetermined period, in particular as an average over 20 seconds.

[0028] By determining the hemodynamic systolic parameter and / or the hemodynamic relaxation parameter as an average over a predetermined period, it becomes possible to have a more robust value of the corresponding parameter. In other words, an outlying extreme value or measurement error will not inadvertently lead to the determination of a coagulation event. The predetermined period can be, for example, a static amount of time such as the example of 20 seconds. In other examples, the period can be defined as the number of subsequent heartbeats, for example, the average can always be obtained over a fixed number of heartbeats such as 15 or 20 heartbeats.

[0029] In a preferred embodiment, determining as an average includes at least one of a filtering process and the determination of a moving average.

[0030] Filtering processes and moving averages are well known and simplify the implementation method for determining the average value. In other examples, other forms for determining the average are also conceivable.

[0031] In a preferred embodiment, the decrease or increase in the hemodynamic contraction parameter and the hemodynamic relaxation parameter is shown based on the comparison of two subsequent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter, respectively.

[0032] In this embodiment, by determining the subsequent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter respectively, a simple comparison of the trend or change of each parameter becomes possible. The subsequent values can be the directly adjacent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter respectively, or there may be an intermediate value between two subsequent values, that is, there is a gap between the first and second parameters respectively.

[0033] In particular, the periods underlying the subsequent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter are preferably sufficiently separated so that sufficient changes can occur in each parameter. Thereby, slight trends or changes induced in the hemodynamic contraction parameter and the hemodynamic relaxation parameter, which would not result in the detection of coagulation for directly adjacent heartbeats, can be detected if the changes over a longer period are sufficiently large. For example, even if the moving average is updated every heartbeat, for example, every about 1 second, it would be preferable to compare the moving averages of two subsequent values that are more than one heartbeat apart, for example, with a underlying period of 20 seconds apart.

[0034] In a preferred embodiment, after determining the coagulation event, the method further includes recognizing or recommending a cleaning event of the arterial line, and confirming the coagulation event if a change in at least one predetermined hemodynamic parameter before and after the cleaning event, particularly the maximum change in blood pressure during systole or end-systolic pressure, exceeds a predetermined cleaning threshold value.

[0035] The step of recognizing or recommending a cleaning event of the arterial line can be performed substantially simultaneously with the step of providing a signal notifying the determined clotting event. For example, as a result of the recommendation of the cleaning event, an additional message or notification instructing the anesthesiologist to perform the cleaning of the arterial line can be displayed on the patient monitor. In other examples, the recommendation of the cleaning event can include the generation of a cleaning signal, which is then used to initiate an automated cleaning of the arterial line. By cleaning the arterial line, the reliability of the measurement results depending on the pulse pressure wave measured through the arterial line will be enhanced.

[0036] In a preferred embodiment, the cleaning event of the arterial line is determined based on at least one significant change in the maximum pressure gradient and the systolic pressure.

[0037] The cleaning event can be regarded as, for example, a sharp pressure peak of 300 mmHg or more by a pressure bag that automatically performs injection to prevent clotting. The higher the location of the pressure bag, the sharper the recognizable pressure peak.

[0038] After such a cleaning event, if the systolic pressure, diastolic pressure, and other hemodynamic parameters suddenly recover to values similar to those before the event and different from those during the event, the clotting can be determined as a true positive event.

[0039] Evaluating or demonstrating the performance of the method according to the present disclosure is possible based on an offline analysis of clinical data including arterial blood pressure waveforms. The determination of the clotting event and the subsequently provided signal notifying the determined clotting event can be tested and confirmed in combination with the evidence that the arterial line was actually subsequently cleaned. However, if a signal notifying the determined clotting event is provided, that is, the clotting event is determined but no cleaning event is detected within a reasonable period after the determination of the clotting event in the offline analysis of the clinical data, this trigger is preferentially classified as a false positive determination.

[0040] A reasonable period in this context can be, for example, 5 minutes. Therefore, it is possible to prove the performance of the coagulation detection algorithm. Since there is a group of coagulation events that an anesthesiologist has not actually recognized as coagulation events until now, in order to score the algorithm performance, true positive events can be weighted higher than, for example, false positive events. Clearly, the number of false positives should not be too large because, for example, there is a possibility of anesthesiologist alarm fatigue.

[0041] In addition, in a preferred embodiment, attenuation can be determined using vibrations in the system after a cleaning event is recognized, and this attenuation is characterized by the instability of the frequency at which it occurs. The determined attenuation can then be advantageously used to characterize the system.

[0042] In a preferred embodiment, the method further includes the step of selecting a subset of available hemodynamic parameters as individual coagulation parameters from a list of available hemodynamic parameters, and the hemodynamic parameters are classified as individual coagulation parameters when the change between "before" and "after" a cleaning event exceeds a predetermined threshold.

[0043] The selection of hemodynamic parameters that are generally appropriate as hemodynamic systolic parameters and hemodynamic relaxation parameters respectively can be based on the scoring of the performance of each parameter based on an offline analysis of clinical data as described above.

[0044] However, coagulation events tend to occur multiple times, for example, in patients under intensive care observation. In such patients, the individual parameters for determining coagulation events may be different from the general parameters determined, for example, by offline analysis of clinical data. Therefore, in order to improve the prediction and determination of future coagulation events for the same patient, it is preferable to evaluate the suitability of alternative or additional parameters after the occurrence of a coagulation event. Therefore, in this embodiment, an individual adaptation or prediction for coagulation events is performed based on actual data, so that subsequent coagulation events can be determined more reliably or even earlier.

[0045] In a preferred embodiment of a method for determining subsequent coagulation events, at least one of the hemodynamic contraction parameter and the hemodynamic relaxation parameter includes a hemodynamic parameter included in the individual coagulation parameter.

[0046] In this embodiment, the individual coagulation parameter selected from the set of individual coagulation parameters can be used, for example, in the form of a combination of parameters or instead of each of the previously considered hemodynamic contraction parameter or hemodynamic relaxation parameter. In some embodiments, the individual coagulation parameters are ranked, and the parameter with the highest rank indicates the signs of coagulation events as early and reliably as possible. The ranking can be performed, for example, using well-known statistical methods for hemodynamic signals.

[0047] In a preferred embodiment, at least one of the hemodynamic contraction parameter and the hemodynamic relaxation parameter is adapted using a machine learning prediction algorithm.

[0048] The present disclosure is not limited to specific machine learning prediction algorithms and can use all machine learning prediction algorithms available to those skilled in the art. The machine learning prediction algorithm can be used to determine both common hemodynamic systolic parameters and / or common hemodynamic relaxation parameters that are generally used as initial parameters for the method according to the present disclosure. In other examples, the machine learning prediction algorithm can also be used to adapt each parameter during patient monitoring.

[0049] In a preferred embodiment, the hemodynamic systolic parameter indicates a decrease in contractility when the change in the hemodynamic systolic parameter exceeds a decrease threshold, and the hemodynamic relaxation parameter indicates an increase in contractility when the change in the hemodynamic relaxation parameter exceeds an increase threshold. At least one of the increase threshold and the decrease threshold is adjusted based on a previously determined coagulation event, particularly based on a coagulation event confirmed in the past.

[0050] According to this embodiment, the thresholds for recognizing increases and decreases in contractility can be adjusted or learned respectively based on the fact that there has been a wash, and also based on whether the wash has caused a significant change in the hemodynamic parameters. This can improve the sensitivity of the method according to the present disclosure.

[0051] In a preferred embodiment, the method further includes the step of adjusting at least one of the increase threshold and the decrease threshold using the hemodynamic systolic parameter and the hemodynamic relaxation parameter before and after flushing the arterial line.

[0052] In a preferred embodiment, the prediction parameters including the increase threshold and the decrease threshold are adapted using a machine learning prediction algorithm.

[0053] Similar to the use of the machine learning prediction algorithm described above with respect to the definition or combination of the hemodynamic contraction parameter and the hemodynamic relaxation parameter, the machine learning prediction algorithm can also be used to adjust the increase threshold and the decrease threshold.

[0054] In a preferred embodiment, the method further includes the step of determining the frequency components of the provided hemodynamic signal, and in the step of determining the coagulation event, the coagulation event is additionally determined based on the determined frequency components, in particular the coagulation event is determined when the frequency component or the change in the frequency component exceeds a predetermined threshold.

[0055] It has been recognized that in addition to the hemodynamic contraction parameter and the hemodynamic relaxation parameter, the frequency components of the hemodynamic signal can be evaluated to determine the occurrence of a coagulation event in the arterial line. Combining the analysis of the hemodynamic contraction / relaxation parameter and the analysis of the frequency components has been particularly beneficial and has shown to enhance the reliability of the proposed method.

[0056] The frequency components are preferably determined based on the hemodynamic signal indicating the blood pressure waveform, for example, after converting it to the frequency domain using Fourier or other suitable transforms. The frequency components are preferably determined as an integral over a specific frequency range or the entire frequency range.

[0057] The change in the frequency component is preferably determined for two subsequent values of the frequency component, and the subsequent values preferably include a time gap between them, as described above with respect to the subsequent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter. This allows gradual trends or shifts to accumulate into large changes that can be noticed and not go undetected. It should be noted that all averaging processes known to those skilled in the art and all further processes described above with respect to the hemodynamic contraction parameter and the hemodynamic relaxation parameter can be similarly applied to the frequency components.

[0058] In a preferred embodiment, the frequency component is determined as the sum of the frequency components within the frequency range of interest, the frequency range of interest includes resonances such as the frequency of interest and in particular the natural frequency of the arterial line, and the frequency component is particularly preferably determined as a relative value scaled by the sum of the frequency components over all frequencies.

[0059] Preferably, the frequency of interest is determined as the frequency having the maximum amplitude. In some embodiments, the frequency of interest can be predetermined and fixed, and in other embodiments, the frequency of interest is variable and may be adapted according to the current maximum amplitude.

[0060] Since the frequency component is preferably scaled with respect to the overall sum over all frequencies, the frequency components in the frequency range of interest can be compared over time, and in particular, the change in the frequency component over time can be analyzed more accurately.

[0061] In a preferred embodiment, the frequency range of interest is determined relative to the frequency of interest and particularly includes frequencies within 50% - 200% of the frequency of interest and / or frequencies having an amplitude exceeding 50% of the amplitude of the frequency of interest. It should be noted that other methods of defining an appropriate range of interest are also conceivable.

[0062] In a preferred embodiment, the method further includes, after determining a coagulation event, performing a washout test, the washout test including the steps of opening the pressure reservoir and causing a sudden stop of the flow resulting in a sudden change in blood pressure, and evaluating the vibration of the arterial line system based on the provided hemodynamic signal indicating the arterial blood pressure waveform for a certain period following the sudden stop, wherein the vibration of the hemodynamic signal is induced by the sudden change in blood pressure, and evaluating the attenuation and natural frequency of the arterial line system based on the evaluated vibration.

[0063] In this embodiment, the presence of a coagulation event can be confirmed using the evaluation of a washing test, for example, to enhance the reliability of the proposed method.

[0064] The period following the rapid stop can include, for example, several seconds, for example 3 seconds or 10 seconds, or the period of subsequent heartbeats. Of course, other methods of determining the appropriate length of the period are also conceivable.

[0065] During this period, for example, what is also known as the attenuation coefficient or attenuation rate can be derived based on the decay of detectable vibrations. The attenuation coefficient explains how the vibration decays over time. The attenuation coefficient can then be compared, for example, with a predetermined coagulation threshold, and the presence of a coagulation event can be confirmed when the attenuation coefficient exceeds the predetermined coagulation threshold. Attenuation can thus be advantageously used to confirm the coagulation of the arterial line, and thus it becomes possible to build a more robust system.

[0066] In addition, at least one dominant frequency can be determined for the induced vibration, which is called the natural frequency. Preferably, the frequency value of the natural frequency can also be evaluated to confirm the presence of a coagulation event. For example, the natural frequency can be compared with a predetermined frequency, and the presence of a coagulation event can be confirmed when the natural frequency deviates from the predetermined frequency by more than a predetermined threshold. The predetermined threshold can be an absolute or relative value such as 10 Hz or 10%, but is of course not limited.

[0067] In a preferred embodiment, the wash test performed in the execution step can be an automated high-speed wash in which an automated washing means capable of inducing a wash that applies pressure into the arterial line and performs a short-time injection of a liquid, preferably physiological saline, automatically operates the opening of the pressurized reservoir and / or the sudden stop of the flow, a manual high-speed wash in which an operator is signaled to perform a manual opening of the pressurized reservoir and / or a sudden stop of the flow, and a manual tapping test, wherein the tapping test includes increasing the blood pressure one or more times by applying an increased pressure through the arterial line, for example, by gently tapping the flexible tubing connected to the arterial line, preferably by suddenly releasing the applied pressure, and signaling the operator to perform the manual tapping test, and includes at least one of the manual tapping tests.

[0068] The high-speed wash test makes it possible to determine in vivo the natural frequency and damping coefficient of an invasive blood pressure monitoring system such as an arterial line system. In the high-speed wash test, a pressurized reservoir capable of generating pressure preferably by gravity or by mechanical pressure is connected to the arterial line through an openable connection. The pressurized reservoir is preferably an infusion bag, and the pressure can be changed by changing the height at which the infusion bag is held. The pressure in the pressurized reservoir is preferably about 200 mmHg or more. To increase the blood pressure in the arterial system, this pressurized reservoir can be opened for a short time, preferably about 3 seconds or less, for example, only for 1 second. By suddenly closing the pressurized reservoir, the blood pressure rapidly decreases, and vibrations of the hemodynamic signal are induced for up to several seconds after the pressurized reservoir is closed.

[0069] Of course, the pressure values and time values are merely examples, and those skilled in the art can use other values of these parameters, for example, dynamically determined values of these parameters.

[0070] For example, vibrations can also be induced in the hemodynamic signal by gently tapping the arterial line with a finger, and this can be used to evaluate the attenuation and natural frequency of the arterial line system. By gently tapping the arterial line with a soft connection / tube, the volume of the arterial system decreases, and as a result, the blood pressure increases. By rapidly releasing the pressure at the connection / tube, a rapid drop in blood pressure is achieved, and vibrations are induced in the hemodynamic signal. These vibrations exist from the moment of the sudden decrease in blood pressure and continue for up to several seconds.

[0071] Signaling the operator to perform a manual tapping test or a manual fast flush test can include signaling the operator in any suitable form of visual, auditory, or other perceptible means. In this case, this method preferably includes a step of determining that the test signaled has been actually performed by the operator. Some examples include an audio confirmation provided by the operator that the test has been actually performed or an input to an interface such as a touch screen. In other examples, this method automatically determines that the test has been performed based on the determination of a rapid increase in pressure.

[0072] In a preferred embodiment, this method further includes, after determining a coagulation event, a step of confirming that the determined coagulation event is actually a true coagulation event based on the evaluated attenuation and natural frequency of the arterial system.

[0073] In a preferred embodiment, the method in the case where a true coagulation event is confirmed further includes a step of performing automated cleaning, and the arterial line includes automated cleaning means capable of inducing cleaning by applying pressure into the arterial line to remove coagulated blood from the arterial line, with a short injection of a liquid, preferably saline.

[0074] Washing the arterial line with saline is presumed to remove coagulated blood from the arterial line.

[0075] Automated cleaning preferentially operates the same pressurized container that can be used to perform high-speed cleaning. However, other means suitable for cleaning arterial lines known in the art can also be used.

[0076] Instead of performing automated cleaning, for example, if automated cleaning means are not attached to the arterial line, an operator can be signaled to perform manual cleaning.

[0077] In a preferred embodiment, the steps of the method are repeated, particularly continuously.

[0078] In a further aspect, a system for notifying of a coagulation event in a human arterial line is proposed. This system includes a hemodynamic signal providing unit for providing a hemodynamic signal indicating the arterial blood pressure waveform in the arterial line, a hemodynamic systolic parameter determination unit for determining hemodynamic systolic parameters related to the contraction of the heart based on the hemodynamic signal, a hemodynamic diastolic parameter determination unit for determining hemodynamic diastolic parameters related to the relaxation of the heart based on the hemodynamic signal, a coagulation event determination unit for determining a coagulation event in the arterial line when the hemodynamic systolic parameter indicates a decrease in contractility and the hemodynamic diastolic parameter indicates an increase in contractility, a notification unit for providing a signal for notifying the determined coagulation event, and includes.

[0079] The system according to this aspect enables achieving the same advantages and benefits as described above for the method of notifying of a coagulation event in an arterial line. Similarly, the system according to this aspect can be combined with any preferred embodiment of the described method, thereby achieving the same benefits.

[0080] The blood flow dynamic signal providing unit, the blood flow dynamic contraction parameter determination unit, the blood flow dynamic relaxation parameter determination unit, the coagulation event determination unit, the frequency component determination unit, and the notification unit can be implemented partially or fully as software and / or hardware. Suitable hardware includes a general-purpose processing unit (CPU) and the like. Each unit may be physically provided in the same location or spatially distributed across different devices. For example, one, multiple, or all of the units can be implemented on a server. In other examples, one, multiple, or all of the units can be integrated into a patient monitor, which is known to be used for monitoring the arterial blood pressure waveform of an arterial line. Furthermore, appropriate units configured to execute the steps of the preferred embodiment of the method according to the present disclosure can be provided and implemented as software and / or hardware partially or fully in the same manner.

[0081] In a further aspect, when a program is executed by a computer, a computer program product is proposed that includes instructions for causing the computer to execute the steps of the method of the first aspect of the present disclosure or a preferred embodiment thereof.

[0082] In a further aspect, a computer-readable data carrier carrying the computer program product of an aspect of the present disclosure is proposed. For example, the computer-readable data carrier can be realized as a flash drive, such as a USB flash drive, a solid-state drive, or a hard disk drive, cloud storage, etc.

[0083] The computer program product according to the present disclosure and the data carrier signal according to the present disclosure make it possible to achieve the same objectives as those described in the context of the method according to the present disclosure. Furthermore, the computer program product and the data carrier signal can also be advantageously configured according to any of the preferred embodiments described for the method according to the present disclosure.

[0084] The present disclosure will be described by way of non-limiting examples shown in the following figures.

Brief Description of the Drawings

[0085]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0086] Figure 1 schematically and illustratively shows an intervention in which an arterial line 1 is inserted into the arm of a patient 2. In this example, the arterial line 1 is inserted into the radial artery, although different arteries may be used in other examples. The arterial line 1 generally includes tubing 3 that is filled with saline and is non-compressible. The saline is generally supplied from a pressurized reservoir such as a pressure bag 5 that is positioned higher than the arterial line 1. A pressure transducer 4 is disposed between the pressure bag 5 and the tubing 3. The pressure transducer 4 is configured to provide a hemodynamic signal indicative of the arterial blood pressure waveform in the arterial line 1 to a patient monitor 6 in this example.

[0087] In some examples, the pressure transducer 4 includes an automatic cleaning system for flushing the arterial line with saline from the pressure bag 5. In other examples, the cleaning system is manually operated.

[0088] In this example, the patient monitor 6 includes a display 8 on which a blood pressure waveform 10 is shown.

[0089] Figure 2 schematically and illustratively shows the arterial blood pressure waveform 10 for one heartbeat in more detail. Figure 2 shows the pressure on the vertical axis with respect to time on the horizontal axis. Other forms of displaying the arterial blood pressure waveform should be considered feasible.

[0090] Figure 2 is provided only for explaining the determination of hemodynamic contraction parameters and hemodynamic relaxation parameters from the hemodynamic signal according to the present disclosure. At point 12, the aortic valve opens and systole begins. During period 14, the pressure increases as blood flows into the artery. At point 16, the maximum systolic pressure occurs. During period 18, the heart valve closes and the pressure continues to decrease as blood flows out of the artery. Finally, at point 20, the minimum diastolic pressure can be obtained.

[0091] In some examples, the period between point 12 and point 16 is considered the systolic period, and the parameters derived from this period are thus due to the contraction of the heart and can be called hemodynamic contraction parameters. These parameters include, but are not limited to, the maximum change in blood pressure during period 14, the end-systolic blood pressure at point 16, or the area under the arterial blood pressure waveform curve above the end-diastolic pressure at point 20 between the start of systole at point 12 and the closure of the aortic valve at the end of systole at point 16.

[0092] Parameters indicating relaxation can include, but are not limited to, the end-diastolic pressure at point 20, the mean arterial pressure as an average over the entire heartbeat, and the inter-beat interval.

[0093] Figure 3 schematically and illustratively shows a flowchart of a method 100 for notifying a coagulation event in the arterial line 1.

[0094] This method includes a step 110 of providing a hemodynamic signal indicating the arterial blood pressure waveform in the arterial line 1.

[0095] This method further includes step 120 of determining hemodynamic contraction parameters related to the contraction of the heart based on the hemodynamic signal, and step 130 of determining hemodynamic relaxation parameters related to the relaxation of the heart based on the hemodynamic signal provided in step 110.

[0096] In step 140, based on the determined hemodynamic contraction parameters and hemodynamic relaxation parameters, when the hemodynamic contraction parameter indicates a decrease in contractility and the hemodynamic relaxation parameter indicates an increase in contractility, a coagulation event in arterial line 1 is determined.

[0097] After determining the coagulation event in step 140, a test can be performed in step 145 to confirm that the arterial line is coagulated. Such a test can include, for example, an automatic high-speed wash test or a request for a manual test. The test in step 145 preferably determines the characteristics of the arterial line, such as the natural frequency and attenuation, by gently tapping the high-speed wash catheter to confirm the presence of the coagulation event.

[0098] After determining the coagulation event in step 140 and, optionally, on the premise that the presence of the coagulation event is confirmed by the test in step 145, a signal notifying the determined coagulation event is provided in step 150.

[0099] Next, in an optional step 160, a cleaning event of arterial line 1 is performed, for example, as a result of automated cleaning, recognized as a result of manual cleaning, or recommended using a signal notified to the operator, for example.

[0100] Subsequently, in step 170, it is used to confirm the occurrence of a coagulation event by whether the change in at least one predetermined hemodynamic parameter before and after the cleaning event exceeds a predetermined cleaning threshold.

[0101] This method further includes step 180 of selecting a subset of the available hemodynamic parameters as individual coagulation parameters from a list of the available hemodynamic parameters. The individual coagulation parameters can be used to determine subsequent coagulation events, and preferably a machine learning prediction algorithm is used to adapt the hemodynamic systolic parameter and / or the hemodynamic relaxation parameter based on the individual coagulation parameters.

[0102] This method further includes step 190 of adjusting at least one of the increase threshold and the decrease threshold using the hemodynamic systolic parameter and the hemodynamic relaxation parameter before and after flushing the arterial line 1. In this example, the increase threshold and the decrease threshold are used to explain the increase in contractility and the decrease in contractility, respectively.

[0103] Finally, this method preferably returns to step 110.

[0104] It should be noted that the repeated or continuous operation of this method is particularly beneficial during patient monitoring. In other examples, for instance, when offline data is analyzed, it is not necessary to repeatedly execute this method. The offline analysis of data is particularly advantageous when the hemodynamic systolic parameter and the hemodynamic relaxation parameter are to be defined and / or optimized.

[0105] Furthermore, it should be noted that steps 110, 120, 130, and 140 are essential for the present invention, while the additional steps 145, 150, 160, 170, 180, and 190 are optional steps that illustrate preferred embodiments that enable obtaining further advantages over the essential method steps 110 to 140.

[0106] Furthermore, in FIG. 3 and also in FIG. 4 described below, the steps shown in a specific order do not mean that they are executed continuously, that is, no restrictions regarding their execution times are meant. For example, steps 120 and 130 can be executed simultaneously, preferably substantially simultaneously with the hemodynamic signal provided in step 110.

[0107] FIG. 4 schematically and exemplarily shows a further method 200 for notifying a coagulation event in an arterial line. Method 200 can be combined with method 100 shown in FIG. 3. In particular, the steps described with reference to method 100 can be integrated into method 200.

[0108] This method includes a step 210 of providing a hemodynamic signal indicating an arterial blood pressure waveform in the arterial line 1.

[0109] This method further includes a step 225 of determining frequency components based on the hemodynamic signal provided in step 110.

[0110] In step 240, a coagulation event in the arterial line 1 is determined based on the determined frequency components of the hemodynamic signal. In particular, the coagulation event is determined when the frequency component or the change in the frequency component exceeds a predetermined threshold.

[0111] After determining the coagulation event in step 240, a test can be performed in step 245 to confirm that the arterial line is coagulated. Such a test can include, similar to step 145, for example, an automatic high-speed flushing test or a request for a manual test. The test in step 245 preferably determines the characteristics of the arterial line, such as the natural frequency and attenuation, by gently tapping the high-speed flushing catheter to confirm the presence of the coagulation event.

[0112] After determining the coagulation event in step 240, and optionally, provided that the presence of the coagulation event is confirmed by the test in step 245, a signal notifying the determined coagulation event is provided in step 250.

[0113] Finally, the method preferably returns to step 210.

[0114] FIG. 5 schematically and exemplarily shows a system 300 for notifying a coagulation event in an arterial line such as the arterial line 1 of human 2 shown in FIG. 1.

[0115] The system 300 includes a hemodynamic signal providing unit 310 for providing a hemodynamic signal indicating the arterial blood pressure waveform 10 in the arterial line 1.

[0116] The system 300 may further include a hemodynamic systolic parameter determination unit 320 for determining a hemodynamic systolic parameter related to the contraction of the heart based on the hemodynamic signal provided by the hemodynamic signal providing unit 310.

[0117] The system 300 may further include a hemodynamic diastolic parameter determination unit 330 for determining a hemodynamic diastolic parameter related to the relaxation of the heart based on the hemodynamic signal provided by the hemodynamic signal providing unit 310.

[0118] The system 300 may further include a frequency component determination unit 325 for determining the frequency component of the hemodynamic signal provided by the hemodynamic signal providing unit 310.

[0119] System 300 further includes a coagulation event determination unit 340 for determining a coagulation event in the arterial line 1. The coagulation event determination unit 340 can be configured to determine a coagulation event when the hemodynamic contraction parameter indicates a decrease in contractility and the hemodynamic relaxation parameter indicates an increase in contractility. Alternatively, or in addition, the coagulation event determination unit can be configured to determine a coagulation event in the arterial line 1 based on the frequency components of the hemodynamic signal, and in particular, the coagulation event is determined when the frequency component or the change in the frequency component exceeds a predetermined threshold value.

[0120] System 300 can further include a coagulation event confirmation unit 345. After the coagulation event determination unit 340 determines a coagulation event, a test can be performed to confirm that the arterial line is coagulated according to step 145 of method 100 or step 245 of method 200.

[0121] System 300 further includes a notification unit 350 for providing a signal to notify the determined coagulation event. The notification unit 345 can be operably coupled to the display 8 of the patient monitor 6 to display the notification thereon. In other examples, notifications by other forms of acoustic, optical or data signals can be implemented.

[0122] System 300 can further include a cleaning recommendation / execution unit 360 configured to execute step 160 of method 100. System 300 can further include a cleaning detection unit 370 configured to execute step 170 of method 100. System 300 can further include a fitting parameter selection unit 380 configured to execute step 180 of method 100. Finally, System 300 can further include a fitting threshold determination unit 390 configured to execute step 190 of method 100.

[0123] By comparing the waveforms obtained by non-invasive continuous blood pressure technologies such as the ClearSight system by Edwards Lifesciences in Irvine, California, with the radial artery pressure waveform simultaneously, a characteristic pattern of the progression of clotting in the arterial line can be recognized in the signal from the radial catheter.

[0124] Although the period of clotting detected by the method 100 of the present disclosure is not always but can ultimately be confirmed to have also been detected by the anesthesiologist (experimenter), this is because the cleaning of the catheter manometer system should normally follow such an event. Usually, invasive arterial blood pressure measurement improves significantly after cleaning of the catheter system. Therefore, using the sharp rise in hemodynamic parameters before and after cleaning the arterial system to resolve the clotting, it can be confirmed that the event was actually due to clotting.

[0125] The present invention results from the simultaneous (offline) comparison of ClearSight and radial blood pressure waveforms in available clinical data. From such observations, the inventors of the present invention were able to derive patterns that can also be recognized when monitoring only the arterial line without another blood pressure for comparison.

[0126] Typical clotting events in the arterial line can be recognized by the method described herein. Using this event, for example, the anesthesiologist can be warned that the data from the radial artery is unreliable due to clotting. The catheter system must be cleaned to solve this problem.

[0127] The various illustrative logical blocks and units described in connection with the embodiments disclosed herein can be implemented or executed in any combination of a general purpose processor, a special purpose processor, a circuit, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gates or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor can be a microprocessor or any conventional processor, controller, microcontroller, circuit, or state machine. The processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0128] The steps of a method or algorithm and units of a system described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module / firmware executed by a processor, or in any combination thereof. The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor.

[0129] Furthermore, examples of the present invention include the following.

[0130] Example 1. A method (100) for notifying a coagulation event in an arterial line (1) of a human (2), comprising: providing a hemodynamic signal indicative of an arterial blood pressure waveform (10) in an arterial line (1) (step 110); determining a hemodynamic systolic parameter related to the contraction of the heart based on the hemodynamic signal (step 120); determining a hemodynamic relaxation parameter related to the relaxation of the heart based on the hemodynamic signal (step 130); when the hemodynamic systolic parameter indicates a decrease in contractility and the hemodynamic relaxation parameter indicates an increase in contractility, determining a coagulation event in the arterial line (1) (step 140); providing a signal notifying the determined coagulation event (step 150); A method (100) comprising:

[0131] Example 2. The hemodynamic systolic parameter includes at least one hemodynamic parameter derivable from the arterial blood pressure waveform between the start of systole and the closure of the aortic valve at the end of systole, The hemodynamic systolic parameter particularly the maximum change in blood pressure during systole, the end-systolic pressure, the area under the arterial blood pressure waveform curve above the end-diastolic pressure between the start of systole and the closure of the aortic valve at the end of systole, including at least one of: The method (100) according to Example 1.

[0132] Example 3. The hemodynamic relaxation parameter is the end-diastolic pressure, the mean arterial pressure, the interbeat interval, including at least one of: The method (100) according to any one of Examples 1 to 2.

[0133] Example 4. The method (100) according to any one of Examples 1 to 3, wherein at least one of the hemodynamic systolic parameter and the hemodynamic relaxation parameter is determined as an average over a predetermined period, particularly as an average over 20 seconds.

[0134] Example 5. The method (100) according to Example 4, wherein determining on average includes at least one of a filtering process and a moving average determination.

[0135] Example 6. The method (100) according to any one of Examples 1 to 5, wherein a decrease or an increase in a hemodynamic contraction parameter and a hemodynamic relaxation parameter is shown based on a comparison of two subsequent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter, respectively.

[0136] Example 7. After determining a coagulation event, a step (160) of recognizing or recommending a cleaning event of an arterial line, and a step (170) of confirming a coagulation event when a change in at least one predetermined hemodynamic parameter before and after the cleaning event, particularly a maximum change in blood pressure or end-systolic pressure during systole, exceeds a predetermined cleaning threshold value, The method (100) according to any one of Examples 1 to 6, further comprising.

[0137] Example 8. The method (100) according to Example 7, wherein the cleaning event of the arterial line is determined based on at least one significant change in a maximum pressure gradient and a systolic pressure.

[0138] Example 9. The method (100) according to Example 7 or Example 8, further comprising a step (180) of selecting a subset of available hemodynamic parameters as individual coagulation parameters from a list of available hemodynamic parameters, wherein when a change between before and after the cleaning event exceeds a predetermined threshold value, the hemodynamic parameter is classified as an individual coagulation parameter.

[0139] Example 10. The method (100) according to Example 9, wherein for determining a subsequent coagulation event, at least one of a hemodynamic contraction parameter and a hemodynamic relaxation parameter includes a hemodynamic parameter included in an individual coagulation parameter.

[0140] Method (100) according to any one of Examples 8 to 10, wherein at least one of the hemodynamic contraction parameter and the hemodynamic relaxation parameter is adapted using a machine learning prediction algorithm.

[0141] Example 12. The hemodynamic contraction parameter indicates a decrease in contractility when the change in the hemodynamic contraction parameter exceeds a decrease threshold, The hemodynamic relaxation parameter indicates an increase in contractility when the change in the hemodynamic relaxation parameter exceeds an increase threshold, wherein at least one of the increase threshold and the decrease threshold is adjusted based on a previously determined coagulation event, in particular based on a coagulation event confirmed in the past. Method (100) according to any one of Examples 1 to 11.

[0142] Example 13. A step (190) of adjusting at least one of the increase threshold and the decrease threshold using the hemodynamic contraction parameter and the hemodynamic relaxation parameter before and after flushing the arterial line. The method (100) according to Example 12, further comprising.

[0143] Example 14. The method (100) according to any one of Examples 12 or 14, wherein the prediction parameters including the increase threshold and the decrease threshold are adapted using a machine learning prediction algorithm.

[0144] Example 15. Further comprising a step of determining the frequency component of the provided hemodynamic signal, wherein in the step (130) of determining the coagulation event, the coagulation event is additionally determined based on the determined frequency component, in particular the coagulation event is determined when the frequency component or the change in the frequency component exceeds a predetermined threshold. Method (100) according to any one of Examples 1 to 14.

[0145] Example 16. The frequency component is determined as the sum of the frequency components within the frequency range of interest, the frequency range of interest includes resonance such as the frequency of interest and in particular the natural frequency of the arterial line (1), and the frequency component is preferably determined as a relative value scaled by the sum of the frequency components over all frequencies. The method (100, 200) of Example 15.

[0146] Example 17. The frequency range of interest is determined relative to the frequency of interest and includes frequencies within 50% to 200% of the frequency of interest and / or frequencies having an amplitude exceeding 50% of the amplitude of the frequency of interest. The method (100, 200) of Example 16.

[0147] Example 18. The steps of the method (100, 200) are repeated, particularly executed continuously, the method (100, 200) according to any one of Examples 1 to 17.

[0148] Example 19. After determining the coagulation event, Performing a cleaning test, the cleaning test including the step of releasing the pressure reservoir and the sudden stop of the flow resulting in a sudden change in blood pressure, and Evaluating the vibration of the arterial line system based on the provided hemodynamic signal showing the arterial blood pressure waveform for a certain period following the sudden stop, the vibration of the hemodynamic signal being induced by the sudden change in blood pressure, and Evaluating the attenuation and natural frequency of the arterial line system based on the evaluated vibration, and Further including the method (100, 200) according to any one of Examples 1 to 18.

[0149] Example 20. The cleaning test performed in the step of execution is Automated high-speed cleaning in which the release of the pressure reservoir and / or the sudden stop of the flow are automatically operated using automated cleaning means capable of inducing cleaning by applying pressure into the arterial line to allow for a short injection of a liquid, preferably physiological saline. Manual high-speed cleaning in which an instruction to perform manual release of the pressure reservoir and / or sudden stop of the flow is signaled to the operator, and A manual tapping test, the tapping test including increasing the blood pressure one or more times by applying an increased pressure through the arterial line, for example by gently tapping the flexible tubing connected to the arterial line, and preferably by suddenly releasing the applied pressure, and signaling an instruction to perform the manual tapping test to the operator, the manual tapping test The method (100, 200) according to example 19, including at least one of.

[0150] Example 21. After determining the coagulation event, Based on the evaluated attenuation and natural frequency of the arterial system, the step of confirming that the determined coagulation event is actually a true coagulation event The method (100, 200) according to example 19 or example 20, further including.

[0151] Example 22. When a true coagulation event is confirmed, The method (100, 200) according to example 21, further including the step of performing automated cleaning, the arterial line including automated cleaning means capable of inducing cleaning that can apply pressure into the arterial line to remove coagulated blood from the arterial line and that is a short-time injection of a liquid, preferably saline.

[0152] Example 23. A computer program product including instructions that, when executed by a computer, cause the computer to execute the steps of any of the methods of examples 1 to 22.

[0153] Example 24. A computer-readable data carrier carrying the computer program product of example 23.

[0154] The foregoing description of the disclosed embodiments has been provided to enable a person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Description of the Reference Numerals

[0155] 1 Arterial line 2 Patient 3 Tubing 4 Pressure transducer 5 Pressure bag 6 Patient monitor 8 Display 10 Blood pressure waveform

Claims

1. A system for notifying a coagulation event in the arterial line (1) of a human (2), comprising: A hemodynamic signal providing unit (310) for providing (110) a hemodynamic signal indicating an arterial blood pressure waveform (10) in the arterial line (1); A hemodynamic systolic parameter determination unit (320) for determining (120) hemodynamic systolic parameters related to the contraction of the heart based on the hemodynamic signal; A hemodynamic diastolic parameter determination unit (330) for determining (130) hemodynamic diastolic parameters related to the relaxation of the heart based on the hemodynamic signal; A coagulation event determination unit (340) for determining (140) a coagulation event in the arterial line when the hemodynamic systolic parameter indicates a decrease in contractility and the hemodynamic diastolic parameter indicates an increase in contractility; A notification unit (345) for providing (150) a signal notifying the determined coagulation event; A system comprising the above.

2. The hemodynamic systolic parameter includes at least one hemodynamic parameter derivable from the arterial blood pressure waveform between the start of systole and the closure of the aortic valve at the end of systole. In particular, the hemodynamic systolic parameter The maximum change in blood pressure during systole, End-systolic pressure, The area under the arterial blood pressure waveform curve above the end-diastolic pressure between the start of systole and the closure of the aortic valve at the end of systole, Includes at least one of the above. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to Claim 1.

3. The hemodynamic diastolic parameter End-diastolic pressure, Mean arterial pressure, Interbeat interval, Includes at least one of the above. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of Claims 1 to 2.

4. At least one of the hemodynamic systolic parameter determination unit (320) and the hemodynamic diastolic parameter determination unit (330) is further configured to determine the respective hemodynamic systolic parameter or hemodynamic diastolic parameter as an average over a predetermined period, in particular as an average over 20 seconds. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of Claims 1 to 3.

5. The system for notifying a coagulation event in the arterial line (1) of a human (2) according to claim 4, wherein at least one of the hemodynamic contraction parameter determination unit (320) and the hemodynamic relaxation parameter determination unit (330) is further configured such that the determination on average includes at least one of a filtering process and a moving average determination.

6. The system according to any one of claims 1 to 5, further comprising an indication unit configured to indicate a decrease or increase in the hemodynamic contraction parameter and the hemodynamic relaxation parameter based on a comparison of two subsequent values of the hemodynamic contraction parameter and the hemodynamic relaxation parameter, respectively, for notifying a coagulation event in the arterial line (1) of a human (2).

7. The system further includes a cleaning recommendation / execution unit (360) configured to recommend a cleaning event of the arterial line, and / or a cleaning detection unit (370) configured to recognize a cleaning event of the arterial line and confirm a coagulation event when a change in at least one predetermined hemodynamic parameter before and after the cleaning event, particularly a maximum change in blood pressure or end-systolic pressure during systole, exceeds a predetermined cleaning threshold value (170). The cleaning detection unit (370) is further configured to determine the cleaning event of the arterial line based on at least one significant change in at least one of a maximum pressure gradient and systolic pressure, in particular. The system for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of claims 1 to 6.

8. The system further includes a matching parameter selection unit (380) configured to select a subset of the available hemodynamic parameters as individual coagulation parameters from a list of available hemodynamic parameters, and when a change between before and after the cleaning event exceeds a predetermined threshold value, the hemodynamic parameter is classified as an individual coagulation parameter. The system for notifying a coagulation event in the arterial line (1) of a human (2) according to claim 7.

9. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to claim 8, wherein at least one of the hemodynamic contraction parameter and the hemodynamic relaxation parameter includes a hemodynamic parameter included in the individual coagulation parameter for determining a subsequent coagulation event.

10. The system according to any one of claims 7 to 9, wherein the system is configured to adapt at least one of the hemodynamic contraction parameter and the hemodynamic relaxation parameter using a machine learning prediction algorithm, for notifying a coagulation event in the arterial line (1) of a human (2).

11. Based on the hemodynamic contraction parameter, it is configured to indicate a decrease in contractility when the change in the hemodynamic contraction parameter exceeds a decrease threshold, and the system is further configured to indicate an increase in contractility when the change in the hemodynamic relaxation parameter exceeds an increase threshold based on the hemodynamic relaxation parameter, and the system is further configured to adjust at least one of the increase threshold and the decrease threshold based on a previously determined coagulation event, particularly based on a coagulation event confirmed in the past, for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of claims 1 to 10.

12. The system according to claim 11, further comprising an adaptation threshold determination unit (390) configured to adjust at least one of the increase threshold and the decrease threshold using the hemodynamic contraction parameter and the hemodynamic relaxation parameter before and after flushing the arterial line.

13. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of claims 11 or 12, wherein the prediction parameters including the increase threshold and the decrease threshold are configured to be adapted using a machine learning prediction algorithm.

14. The system further includes a frequency component determination unit (325) configured to determine the frequency components of the provided hemodynamic signal and In addition, the coagulation event determination unit (340) is further configured to determine the coagulation event based on the determined frequency components, and in particular, the coagulation event is determined when the frequency components or the change in the frequency components exceeds a predetermined threshold value. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of claims 1 to 13.

15. The frequency component determination unit (325) is further configured to determine the frequency component as the sum of the frequency components within a frequency range of interest, and the frequency range of interest includes resonances such as the frequency of interest and in particular the natural frequency of the arterial line (1), and the frequency component is preferably determined as a relative value scaled by the sum of the frequency components over all frequencies. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to claim 14.

16. The system is further configured to determine the frequency range of interest for the frequency of interest, and in particular includes frequencies within 50% to 200% of the frequency of interest and / or frequencies having an amplitude exceeding 50% of the amplitude of the frequency of interest. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to claim 15.

17. After determining the coagulation event, the system is further configured to perform a flushing test, the flushing test includes opening a pressure reservoir and a sudden stop of the flow resulting in a sudden change in blood pressure, and the system is further configured to evaluate the vibration of the arterial line system based on the provided hemodynamic signal indicating the arterial blood pressure waveform for a certain period following the sudden stop, and the vibration of the hemodynamic signal is induced by the sudden change in blood pressure. The system is further configured to evaluate the attenuation and natural frequency of the arterial line system based on the evaluated vibration. A system for notifying a coagulation event in the arterial line (1) of a human (2) according to any one of claims 1 to 16.

18. The flushing test includes Automated high-speed cleaning in which the opening of the pressurized reservoir and / or the sudden stop of the flow are automatically operated using automated cleaning means capable of inducing cleaning by applying pressure into the arterial line to effect a short injection of a liquid, preferably saline solution. Manual high-speed cleaning in which an operator is signaled to perform a manual opening of the pressurized reservoir and / or a sudden stop of the flow, and A manual tapping test, the tapping test including increasing the blood pressure one or more times by applying an increased pressure through the arterial line, for example by gently tapping a flexible tubing connected to the arterial line and preferably by suddenly releasing the applied pressure, and signaling the operator to perform the manual tapping test. A system for notifying of a coagulation event in the arterial line (1) of a human (2) according to claim 17, including at least one of the above.

19. After determining a coagulation event, the system is further configured to confirm that the determined coagulation event is actually a true coagulation event based on the evaluated attenuation and natural frequency of the arterial system. In particular, the system is further configured to perform automated cleaning when a true coagulation event is confirmed, and the arterial line includes automated cleaning means capable of inducing cleaning by applying pressure into the arterial line to effect a short injection of a liquid, preferably saline solution, to remove coagulated blood from the arterial line. A system for notifying of a coagulation event in the arterial line (1) of a human (2) according to claim 17 or 18.

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