Patent ID: 12251505

DETAILED DESCRIPTION OF THE FIGURES

In the following, further example embodiments will be explained in more detail with reference to the accompanying Figures. In the various Figures, like elements are denoted by identical reference numerals and repeated description thereof may be omitted in order to avoid redundancies.

In the following description, a dialysis device1for performing a dialysis treatment and a method for monitoring at least one operating status of the dialysis device1are described. The dialysis device1, which has already been described in general in the above, is depicted in the Figures very schematically and exemplary in regard to an extracorporeal blood circuit10with at least a dialysis filter5and a liquid conducting system2.

Accordingly, a dialysis device1with a liquid conducting system2is schematically shown inFIG.1, wherein the liquid conducting system2is an extracorporeal blood circuit10. For the further description, a blood feed corresponds to a first section3of the liquid conducting system2and a blood return corresponds to a second section of the liquid conducting system2.

The dialysis device1furthermore comprises a dialysis filter5, which is arranged between the blood feed line13and the blood return line14. The blood feed line13, also called arterial feed line, is connected to the patient via a connection, not shown, to withdraw blood from the circuit or circulation of the patient. By the same token, the blood return line14, also called venous return line, is also connected to the patient via a connection, not shown, to return the blood treated in the dialysis filter5to the circuit or circulation of the patient.

The dialysis device1furthermore comprises a pump9, which is depicted in the form of a flexible tube or peristaltic pump, in order to feed the blood withdrawn from the patient through the extracorporeal blood circuit10.

The dialysis device1furthermore comprises a control device100, which is configured to control the treatment of a patient. The control device100controls, for example, the functioning of the pump9and/or switches the clamp12.

Furthermore, an indicating or display device110is provided, by which operating statuses of the dialysis device1may be displayed. The display device110in the depicted exemplary embodiment is schematically shown in the form of a monitor. However, other display devices or indicating devices are possible, such as acoustic or haptic devices.

In order to treat the blood of a prescribed dialysis patient with the dialysis device, the blood feed line13is connected with the circulation of the patient, for example, via a cannula. The withdrawn blood is fed via the pump9to the dialysis filter5, wherein the blood is treated by means of known dialysis methods. For example, a hemodialysis, a hemofiltration, a Hemodiafiltration, or another known dialysis method may be performed in the dialysis filter5. The treated blood is then returned to the patient via the blood return line14, which is also connected to the circulation of the patient.

A differential pressure sensor6measures a differential pressure Nam between the pressure p1in the blood feed line13, which corresponds to an arterial pressure, and the pressure p2in the blood return line14, which corresponds to a venous pressure. The measured differential pressure Nam can be used e.g. to determine an operating status of the dialysis device1, for example, to monitor a correct functioning of the dialysis device1with regard to the functioning of further pressure sensors, which are not shown inFIG.1.

InFIG.1, a configuration of the dialysis device1is schematically shown, wherein only the differential pressure sensor6and a monitoring unit11, which is configured to determine an operating status based on the differential pressure pdiffmmeasured by the differential pressure sensor6, are provided.

Depending on the determined operating status based on the measured differential pressure pdiffm, the dialysis treatment is either continued in this operating status or an error notification occurs and/or the blood flow in the extracorporeal blood circuit is stopped. For this purpose, the operating status determined by the monitoring unit11may be communicated to the control device100and the control device100accordingly ends the treatment or blocks the beginning of a treatment. The determined operating status may, alternatively, or in addition, also be communicated to a display device110to be displayed thereon.

When the measured differential pressure Nam corresponds, for example, to a nominal value of a normal dialysis procedure, the dialysis procedure is continued. However, if the measured differential pressure pdiffmdeviates from this nominal value, for example, in the case, wherein the venous needle, which returns the treated blood to the patient, is dislocated or slid out or another form of needle disconnection has occurred, thereby causing a pressure drop in the blood return line14, this is noticed by the monitoring unit11and an error notification to the user occurs and/or the extracorporeal blood circuit is immediately stopped to avoid a safety hazard for the patient due to a potential high blood loss.

This alarm threshold may not only be exceeded in the case of said deviation from a nominal value, but also upon a corresponding change of the differential pressure pdiffm, such that also in the case of a change of the differential pressure Nam an alarm may be triggered or the dialysis may be stopped. For example, in case of a sudden change of the differential pressure pdiffm, it may be assumed that an irregularity relating to the integrity of the connection of the extracorporeal blood circuit with the patient exists and hence a needle disconnection may have occurred.

The evaluation of the course of the differential pressure pdiffmover time or the comparison of the measured differential pressure pdiffmwith a nominal value is provided by the monitoring unit11, which is configured to perform the corresponding analyses. The monitoring unit11may e.g. be provided in the form of a hardware module and/or in the form of a software module. According to the result of the evaluation the monitoring unit11then sends an alarm notification and/or a command to abort or stop the dialysis treatment, when an alarm condition is achieved or exceed.

Furthermore, a control device100and/or a display device110of the dialysis device1may be provided. The control device100may be configured to interrupt or stop a dialysis treatment and/or block a future treatment based on a message from the monitoring unit11. The display device110may be configured to output a notification based on the determined operating status.

The monitoring unit11and/or the control device100and/or the display device110may also be formed as a common unit, for example, in the form of a control device of a dialysis device with a common processor.

The monitoring unit11may e.g. be formed such that it may receive the signal of the differential pressure sensor6and may e.g. comprise one or more processors and a storage to store a program, by which the monitoring steps may be performed on the processor. The monitoring unit11may accordingly be realized as a computer with corresponding buses integrated in the dialysis device1.

The control device100may also be provided such that only the program code for the control is different from the program code of the monitoring unit11, wherein at least partly the same hardware is used, e.g. a common processor. The control device100and the monitoring unit11may also be present in different software modules, for example.

The control device100may be programmed to block or stop a treatment with the dialysis device1, to avoid a starting of, or to stop, a blood pump. The blocking may also be provided by depicting that an action to be performed by a user is not performable. For example, an actuation field on the machine or on a display of the machine may not be activatable.

The display device110may be present in the form of a display screen, for example in the form of a touch screen, and/or a loud speaker to output acoustic signals and/or an optical transducer, such as a lamp.

InFIG.2a diagram is shown, which depicts a desirable operating status A and an undesirable operating status B of the dialysis device1fromFIG.1. Here, the schematic course of the pressure p [mmHg] of the measured differential pressure pdiffmand the schematic course of the pressure p1in the blood feed line13and the pressure p2in the blood return line14over time t [5] are plotted. The values of the pressure p1in the blood feed line13and the pressure p2in the blood return line14are only schematically depicted for illustration and are not necessarily measured directly by means of the dialysis device fromFIG.1—accordingly, no pressure measuring devices for the pressures in the blood feed line13and in the blood return line14are shown inFIG.1.

For a simplified representation the shown pressures are depicted linearly, which may correspond e.g. to an average value of the pressures. The actual pressures may obviously vary periodically with the heart beat and the pumping movement of the pump9. In the desired operating status A, the pressure p1in the blood feed line13and the pressure p2in the blood return line14essentially run constant at least with respect to their average value, such that also the differential pressure Nam measured by means of the differential pressure sensor6is essentially a constant value. In such a case, no error or failure alarm and/or command to stop the treatment is generated by the monitoring unit11.

The undesirable operating status B schematically shows the case of an error, wherein the venous needle, which should return the purified blood to the patient, is dislocated or disconnected from the vein of the patient (VND, Venous Needle Disconnect). When a connection between the needle, i.e. the exit of the blood return line14, and the vein of the patient no longer exists, a (marginal) pressure drop of the pressure p2in the blood return line14occurs. Based on said pressure drop, the differential pressure pdiffmmeasured by the differential pressure sensor6also changes. The monitoring unit11detects this change of the pressure drop of the differential pressure pdiffmand sends an error notification and/or initiates an immediate interruption of the dialysis process or the pump9.

InFIG.3a dialysis device1is shown with an extracorporeal blood circuit10having a first pressure sensor7arranged in a first section3, which is arranged here at a blood feed line13, and a second pressure sensor8arranged in a second section4, which is arranged here at a blood return line14. A differential pressure sensor6is depicted between the first section3and the second section4. In addition, the dialysis device comprises a monitoring unit11, which is configured to determine a correct functioning of the first and/or second pressure sensor7,8, and accordingly determines the operating status in this manner.

By means of the dialysis device1shown inFIG.3it is hence possible to verify or check the functioning of the first and/or second pressure sensors7,8.

The dialysis device1comprises again a pump9to feed the blood withdrawn from a patient and a dialysis filter5. To treat the blood of a patient prescribed with dialysis by means of the dialysis device1, the blood feed line13is connected to a vein of the patient.

The blood withdrawn from the patient is fed via the pump9to the dialysis filter5, wherein the blood of the patient is purified by means of known dialysis methods, for example, a hemodialysis, a hemofiltration, a hemodiafiltration, or another dialysis method.

The purified blood is then returned to the patient via a blood return line14, which is also connected with this vein of the patient. The differential pressure pdiffmbetween the pressure p1in the blood feed line13, i.e. the first section3of the liquid conducting system2, and the pressure p2in the blood return line14, i.e. the second section4of the liquid conducting system2, is measured via the differential pressure sensor6. In addition, the pressure p1in the first section3is measured by the first pressure sensor7and the pressure p2in the second section4is measured by the second pressure sensor8.

If the measured differential pressure Nam is considered individually, an assessment may be made regarding the operating status of the dialysis device1and the dialysis method may be accordingly continued or interrupted, as already described in view ofFIG.1.

In order to carry out a monitoring of the first and/or second pressure sensor7,8, a differential pressure pdiffbis calculated in the monitoring unit11from the measured pressure p1in the first section3and the measured pressure p2in the second section4. Then, the differential pressure pdiffmas measured by the differential pressure sensor6and the calculated differential pressure pdiffbare compared with each other, for example, subtracted from each other. From the comparison between the measured differential pressure Nam and the calculated differential pressure pdiffba resulting pressure pies is obtained.

In the case, wherein both pressure sensors7,8are functioning correctly, i.e. wherein the pressure sensor7correctly measures the pressure p1in the first section3and the pressure section8correctly measures the pressure p2in the second section4, the measured differential pressure and the calculated differential pressure correspond to each other, i.e. the resulting pressure pies is zero or at least constant over time.

In the case wherein both pressure sensors7,8are not functioning correctly, i.e. wherein the pressure sensor7does not correctly measure the pressure p1in the first section3and the pressure section8does not correctly measure the pressure p2in the second section4, the measured differential pressure pdiffmand the calculated differential pressure pdiffbdo not correspond to each other, i.e. the resulting pressure presdoes not equal zero or changes over time. The evaluation of the resulting pressure pres, i.e. the calculation of the resulting pressure presfrom the measured differential pressure pdiffmand the calculated differential pressure pdiffband the comparison to a nominal value (for example zero) is performed by the monitoring unit11. When a deviation of the resulting pressure presfrom the nominal value is detected, an error notification occurs and/or the extracorporeal blood circuit10is stopped.

An exemplary pressure course is schematically shown inFIG.4for the case wherein both pressure sensors7,8are measuring correctly. The diagram inFIG.4shows the measured pressure p1, p2, pdiffm, and the calculated pressures pdiffband pres. The pressure course p [mmHg] over time t [s] is plotted for each pressure. As evident from the diagram, do the calculated differential pressure pdiffband the measured differential pressure Nam correspond to each other, i.e. the difference between the calculated differential pressure pdiffband the measured differential pressure pdiffmis zero. In this case, no error notification is provided by the monitoring unit11and the dialysis method is continued.

In the case, wherein the pressure sensors6,7,8having a level of tolerance are used, a difference will exist between the measured and hence tolerance containing differential pressure pdiffmand the calculated differential pressure pdiffb, which also comprises a tolerance, as it is calculated from two tolerance containing measurement values p1, p2, such that the resulting pressure does not equal zero, but is essentially constant over time. The analysis by the monitoring unit11may take this into account and may hence still consider a deviation from the resulting pressure from the zero-line in the range of a predefined tolerance to not constitute an error.

InFIG.5a schematic diagram is depicted, which shows an exemplary pressure course for the case, wherein the second pressure sensor8, which should measure the pressure p2in the blood return, does not measure correctly. The diagram inFIG.5shows the measured pressures p1, p2, pdiffmand the calculated pressures pdiffband pres. The pressure course p [mmHg] is plotted over time t [5].

As evident from the diagram, the calculated differential pressure pdiffband the measured differential pressure pdiffmdo not correspond to each other, i.e. the difference between the calculated differential pressure pdiffband the measured differential pressure pdiffmdoes not equal zero and the deviation exceeds a predefined tolerance. The monitoring unit11detects said deviation of the measured differential pressure pdiffmfrom a nominal value and sends an error notification or stops the extracorporeal blood circuit10.

In each of theFIGS.6and7a dialysis device1is shown with an extracorporeal blood circuit10having a first pressure sensor7arranged in a first section3, which corresponds to the blood feed line13, and a second pressure sensor8arranged in a second section4, which corresponds to the blood return line14. As described in the above, differential pressure sensors may be arranged between different or various sections of the liquid conducting system2and the functioning of the pressure sensors arranged at said sections may accordingly be monitored by the respective differential pressure sensor.

Accordingly, various different sections of the liquid conducting system2as well as pressure sensors measuring the pressure in said sections are exemplary shown inFIG.6.

Hence, pressure sensors are shown in the form of a pressure sensor7for determining a pressure p1between an arterial end of the arterial feed13and the blood pump9, a pressure sensor8for determining the pressure p2between a venous end of the venous blood return13and the dialyzer or dialysis filter5, a pressure sensor7afor determining a pressure p3in a section20of the liquid conducting system2between the blood pump9and the dialyzer or dialysis filter5, a pressure sensor7bfor determining a pressure p4in a dialysate line downstream of the dialyzer5, and/or a pressure sensor7cfor determining a pressure p5in the dialysate line upstream of the dialyzer5. The dialyzer5forms a dialysis liquid circuit50with its feed lines and return lines.

InFIG.7various sections of the liquid conducting system2and corresponding differential pressure sensors for measuring the differential pressure between said sections are shown inFIG.7.

In this Figure, various arrangement possibilities of differential pressure sensors6ato6care illustrated. The pressure sensors6ato6cmay be positioned in sections of ranges with various pressure regimes. The dialysis device1, which is shown inFIGS.6and7, comprises according to the pressure sensors7ato7cand the differential pressure sensors6ato6crespective individual or combined monitoring units, which are, however, not depicted to provide a better overview.

In the sections between which a differential pressure sensor6ato6cis arranged, an element may be positioned, which may influence, due to its resistance, the pressure transmission from a first section, e.g. a blood feed line13, to a second section4, e.g. a blood return line14. This element may be e.g. a pump, in particular a peristaltic pump, hollow fibers of a dialysis membrane, a dialysis membrane, a flow reducer, a valve, a chamber that is partly filled during operation, or a similar element. Said element may also be a pressure generating element, for example, a pump, wherein the pressure fluctuations before and after said element are in phase to each other.

If said pressure influencing elements are passive elements and if the pressures in both of the sections3,4, are generated by completely different pressure generators, e.g. by two pumps that operate independently from each other, it may be required to average the signal over a predefined time in order to average these independent fluctuations of the pressure signals to a stable value. This may e.g. be the case, when the first section is positioned in the extracorporeal blood circuit10and the second section is positioned on the side of the dialysis liquid circuit50.

The dialysis device1may also comprise a differential pressure sensor6ato6c, which is connected to more than two sections3,4. Furthermore, a control (not shown) may be provided, which is configured to respectively connect exactly two sections3,4via the differential pressure sensor6ato6cand to perform one of the described monitoring methods for these sections3,4and/or the pressure sensors7ato7cconnected with said sections.

In the storage unit (memory) of the dialysis device1it may be stored how long or for how many measurement values the averaging must be applied, dependent on the respectively connected sections or pressure sensors.

A further parameter, which is stored in the storage unit, for the duration or the number of the measurement values for the averaging, may also be the velocity, with which the pumps of the dialysis device transport the liquid through the respective sections3,4. For this purpose, e.g. a chart or table or an equation may be stored in the storage unit. In the case, wherein the pressures of the individual sections3,4are each measured by independent pressure sensors, the pressure courses may be averaged by means of a program being run by a processor in the dialysis device until the fluctuations of the pressure courses have dropped below a predefined threshold stored in the storage unit.

InFIG.8a method for monitoring an operating status of a dialysis device is shown in a schematic depiction. The method is preferably performed with a dialysis device1as described in the above, which comprises a liquid conducting system2with a first section3and a second section4.

In a first step S1of the depicted method, a differential pressure pdiffmis measured between a first pressure p1in the section3and a second pressure p2in the second section by means of a differential pressure sensor6.

In a second step S2an operating status is determined based on the measured differential pressure pdiffm.

When an undesirable operating status is determined in step S2, e.g. in the case, wherein the venous needle, by which the purified blood is returned to the patient, is accidentally disconnected from the venous patient access of the patient (VND, Venous Needle Disconnect), the treatment is either immediately interrupted to avoid a safety hazard for the patient and/or a notification is outputted, e.g. via a display device110, in step S4.

When the determining of the operating status in step S2results in the presence of a desirable operating status, e.g. in the case, wherein the differential pressure is essentially constant and the dialysis may hence be safely and effectively performed, the treatment is continued.

InFIG.9a schematic depiction of the method for monitoring an operating status of a dialysis device1based on a calculated differential pressure pdiffband a measured differential pressure Nam is shown.

In a step S4a first pressure p1is measured in a first section3. In a step S5, a second pressure p2is measured in a second section4. By means of the measured first pressure p1and the measured second pressure p2a differential pressure pdiffbis calculated in a step S6.

In a step S1, a differential pressure pdiffmbetween the first pressure p1in the section3and the second pressure p2in the second section4is measured by means of the differential pressure sensor6, either in parallel, thereafter, or also beforehand.

By means of the calculated differential pressure pdiffband the measured differential pressure pdiffma resulting pressure presis calculated in a step S8.

Based on the calculated resulting pressure pres, the operating status of the dialysis device1is determined in a step S7and an analysis is performed in a step S9. When the analysis provides that an undesirable operating status exists, the dialysis treatment is interrupted.

Where applicable, all of the individual features that are depicted in the exemplary embodiments may be combined and/or replaced without leaving the scope of the present disclosure.

LIST OF REFERENCE NUMERALS

1Dialysis device2Liquid conducting system3First section4Second section5Dialysis filter6Differential pressure sensor6a-6cDifferential pressure sensor7First pressure sensor7a-7cPressure sensor8Second pressure sensor9Pump10Extracorporeal blood circuit11Monitoring unit for determining an operating status12Clamp13Blood feed14Blood return100Control device110Display devicep1First pressurep2Second pressurepartArterial pressurepvenVenous pressurepdiffmMeasured differential pressurepdiffbCalculated differential pressurepresResulting differential pressureA Desired operating statusB Undesired operating statusS1Measuring differential pressure pdiffmS2Determining the operating statusS3Interrupting a dialysis treatmentS4Measuring of the pressure p1S5Measuring of the pressure p2S6Calculating the differential pressure pdiffbS7Determining the operating statusS8Calculating a resulting pressure piesS9Analysis