Extracorporeal blood treatment device with function-monitoring system

Abstract

An extracorporeal blood treatment device with a function-monitoring system, wherein the extracorporeal blood treatment device for connection to the vascular system of a patient has an input branch and an output branch. The extracorporeal blood treatment device is equipped, in a first circuit, with at least one first pump arranged between the input branch and output branch for moving the patient's blood, and, in a second circuit filled with liquid and thermally connected to the first circuit of the extracorporeal blood treatment device via a heat exchanger, it has temperature-influencing means. The function-monitoring system has, in the second circuit, two temperature sensors which are arranged upstream (TS2.sub.auf) and downstream (TS2.sub.ab), respectively, with respect to the heat exchanger, in addition, temperature sensor TS1.sub.ab is arranged in the output branch of the first circuit, downstream from the heat exchanger. The function-monitoring system moreover comprises a computer system which is operatively connected to the aforementioned temperature sensors and the temperature-influencing means and which, after the temperature has been influenced, establishes, from the detected temperature values, corresponding thermodilution curves (TDK1.sub.ab, TDK2.sub.ab, TDK2.sub.auf) and, in order to determine an indicator of the function of the extracorporeal blood treatment device, relates the TDK2.sub.ab and the TDK.sub.1ab to each other.

Claims

1. An extracorporeal blood treatment device having a function-monitoring system, wherein the extracorporeal blood treatment device comprises an afferent line and an efferent line for connecting to the vascular system of a patient, wherein in a first circuit the extracorporeal blood treatment device has at least one first pump arranged between the afferent line and the efferent line for moving the patient's blood, and comprises a temperature adjusting device in a second, liquid-filled circuit that is thermally connected to the first circuit of the extracorporeal blood treatment device by a heat exchanger, wherein the function-monitoring system comprises: a. a temperature sensor TS2.sub.up arranged in the second circuit upstream of the heat exchanger and a temperature sensor TS2.sub.down arranged in the second circuit downstream of the heat exchanger; b. a temperature sensor TS1.sub.down arranged in the efferent line of the first circuit of the extracorporeal blood treatment device downstream of the heat exchanger; and c. a computer system connected to the temperature sensors (TS2.sub.up, TS2.sub.down, TS1.sub.down) and the temperature adjusting device, and configured to use the temperature adjusting device to induce a temperature bolus in the second circuit of the extracorporeal blood treatment device, to record the temperatures T2.sub.up, TS2.sub.down, TS1.sub.down detected at the temperature sensors TS2.sub.up, TS2.sub.down, TS1.sub.down, respectively, as a function of time and to determine and evaluate corresponding thermodilution curves (TDK), and is furthermore configured to relate TDK2.sub.down and TDK1.sub.down to one another and to determine an indicator of the extracorporeal blood treatment device function from a ratio of TDK2.sub.down and TDK1.sub.down, and wherein the indicator of the functionality of the extracorporeal blood treatment device is an indicator of a functionality of a membrane in the extracorporeal blood treatment device.

2. The device according to claim 1, wherein the computer system is designed to relate TDK2.sub.up and TDK1.sub.down to one another and to determine a further indicator of the extracorporeal blood treatment device function from the relationship of TDK2.sub.up and TDK1.sub.down.

3. The device according to claim 1, wherein the function-monitoring system further comprises a temperature sensor TS1.sub.up arranged in the afferent line of the first circuit upstream of the heat exchangers of the extracorporeal blood treatment device, wherein the indicator of extracorporeal blood treatment device function is corrected by a correction factor from the relationship of TDK2.sub.up and the temperature T1.sub.up detected by temperature sensor TS1.sub.up.

4. The device according to claim 1, wherein the computer system is configured to control at least one second pump connected to the temperature adjusting device in the second circuit such that a pump speed is adjusted to generate a temperature difference.

5. The device according to claim 4, wherein the second pump is arranged in the second circuit upstream of the heat exchanger.

6. The device according to claim 1, wherein the temperature adjusting device generate a temperature bolus in the first circuit of the extracorporeal blood treatment device.

7. The device according to claim 1, wherein the temperature adjusting device are arranged downstream of the first pump.

8. The device according to claim 1, wherein the temperature adjusting device comprise a switch for switching between at least two temperatures.

9. The device according to claim 8, wherein the switch switches between at least two different temperature-controlled liquid reservoirs.

10. The device according to claim 1, wherein the extracorporeal blood treatment device is a device for extracorporeal membrane oxygenation.

11. The device according to claim 10, wherein the temperature adjusting device are arranged in the region of an oxygenator of the extracorporeal membrane oxygenation.

12. The device according to claim 1, wherein the temperature adjusting device are connected externally to a heating unit of the extracorporeal blood treatment device.

13. A method for monitoring a functional state of an extracorporeal blood treatment device according to claim 1, comprising: a. Inducing a temperature bolus in the second circuit of the extracorporeal blood treatment device, wherein a temperature deviation underlying the temperature bolus is caused by the temperature adjusting device of the second circuit of the extracorporeal blood treatment device, wherein the first circuit of the extracorporeal blood treatment device is thermally connected to the second circuit of the extracorporeal blood treatment device via a heat exchanger; b. Detecting a temperature T2.sub.up in the second circuit of the extracorporeal blood treatment device by a temperature sensor TS2.sub.up arranged upstream of the heat exchanger; c. Detecting a temperature T2.sub.down in the second circuit of the extracorporeal blood treatment device by a temperature sensor TS2.sub.down downstream of the heat exchanger and detecting a temperature T1.sub.down in the efferent line of the first circuit of the extracorporeal blood treatment device by a temperature sensor TS1.sub.down arranged downstream of the heat exchanger; and d. Determining an indicator of a functionality of the extracorporeal blood treatment device by relating the thermodilution data TDK2.sub.down and TDK1.sub.down determined from the temperatures T2.sub.down and T1.sub.down detected by temperature sensor TS2.sub.down and temperature sensor TS1.sub.down.

14. The method according to claim 13, additionally comprising the step: d. Determining a further indicator of the functionality of the extracorporeal blood treatment device by relating the thermodilution data TDK2.sub.up and TDK1.sub.down determined from the temperatures T2.sub.up and T1.sub.down detected by temperature sensor TS2.sub.up and temperature sensor TS1.sub.down.

15. The method according to claim 13, additionally comprising the steps: e. Detecting a temperature in the afferent line of the first circuit of the extracorporeal blood treatment device by a temperature sensor TS1.sub.up arranged upstream of the heat exchanger, and correcting the indicator of the functionality of the extracorporeal blood treatment device by a correction factor from the relationship of a TDK2.sub.up and the temperature T1.sub.up detected by temperature sensor TS1.sub.up.

16. A computer system configured to interact with an extracorporeal blood treatment device having a function-monitoring system according to claim 1, wherein the computer system comprises the following: a connector for connecting the computer system to the temperature sensors TS2.sub.up, TS2.sub.down, TS1.sub.down, and the temperature adjusting device, and executable commands stored in memory to cause the computer system: a. to control a temperature adjusting device in the second circuit of the extracorporeal blood treatment device in order to induce a temperature bolus in the second circuit of the extracorporeal blood treatment device; b. to record the temperatures T2.sub.up, T2.sub.down, T1.sub.down detected at the temperature sensors TS2.sub.up, TS2.sub.down, TS1.sub.down, in each case as a function of time, and accordingly to detect and evaluate to thermodilution (TDK); and, c. to relate TDK2.sub.down and TDK1.sub.down to one another and determine an indicator of the functionality of the extracorporeal blood treatment device from a ratio of TDK2.sub.down and TDK1.sub.down, and wherein the indicator of the functionality of the extracorporeal blood treatment device is an indicator of a functionality of a membrane in the extracorporeal blood treatment device.

17. A non-volatile, computer-readable storage medium with computer-readable instructions for determining an indicator of a functionality of an extracorporeal blood treatment device having a function-monitoring system according to claim 1, wherein the computer-readable instructions are executable by a computer system to cause the computer system: a. to control a temperature adjusting device in the second circuit of the extracorporeal blood treatment device to induce a temperature bolus in the second cycle of the extracorporeal blood treatment device; b. to record the temperatures T2.sub.up, T2.sub.down, T1.sub.down detected on the temperature sensors TS2.sub.up, TS2.sub.down, TS1.sub.down, in each case as a function of time, and to determine and evaluate thermodilution curves (TDK) accordingly; and, c. to relate the TDK2.sub.down and the TDK1.sub.down to one another and to determine the indicator of the functionality of the extracorporeal blood treatment device from a ratio of TDK2.sub.down and TDK1.sub.down, and wherein the indicator of the functionality of the extracorporeal blood treatment device is an indicator of a functionality of a membrane in the extracorporeal blood treatment device.

Description

BRIEF DESCRIPTION OF THE FIGURE

(1) The drawing is purely schematic and, for illustrative reasons, is not true to scale. In particular, the relationships between the dimensions, especially diameters, tube lengths, and external dimensions may differ from actual embodiments. In practice, the dimensions can be dimensioned based on the requirements in individual cases and based on common standard parts.

(2) FIG. 1 shows a schematic overview of the disclosed extracorporeal blood treatment device with a function-monitoring system, wherein the interaction with the vascular system of a patient is shown for purposes of illustration.

PREFERRED EMBODIMENT OF THE DISCLOSURE

(3) FIG. 1 shows a schematic overview of the disclosed extracorporeal blood treatment device with a function-monitoring system. The extracorporeal blood treatment device (EBTD, 10) is connected to the venous vascular system of a patient via an afferent line (11) and an efferent line (12). The extracorporeal blood treatment apparatus can be, for example, a device for extracorporeal membrane oxygenation (veno-venous ECMO, vvECMO, as shown in FIG. 1) or a device for liver dialysis. The afferent line (11) is introduced, for example, via the femoral vein and comes to rest in the lower caval vein (V. cava inferior) below the convergence of the hepatic vein. The efferent line (12) is introduced, for example, via the jugular vein and comes to rest in the upper cval vein (V. cava superior) immediately in front of the right atrium. In the case of ECMO, low-oxygen, venous blood is supplied to the blood treatment device via the afferent line (11), while the oxygenated blood reaches the right atrium via the efferent line (12). The disclosed EBTD can also be used as an ECMO in situations in which the deoxygenated blood is conducted to the ECMO via the femoral vein and the oxygenated blood is returned to the vascular system of the patient via the femoral artery (vaECMO); in this arrangement, the ECMO can take over the entire pumping action in the patient's circulation in addition to the device circuit. For treatment, the patient's blood is conducted by means of a pump (13) over a membrane, for example a hemodialysis membrane, a hemofiltration membrane, a hemodiafiltration membrane, or an oxygenator membrane of an ECMO. Input and efferent lines, as well as the lines connected to the actual blood treatment device (membrane), form a first circuit. The pump (13), which is preferably embodied as a centrifugal pump, is used to control and regulate the circulation of the blood through the first circuit. The pumps used in an extracorporeal circuit of conventional blood treatment devices are usually connected to a control device and can thus be controlled directly so that these pumps can either provide a relatively constant flow rate or a variable flow rate through the extracorporeal circuit and the actual blood treatment device (membrane). In the disclosed EBTD with a function-monitoring system, in addition to the first circuit, which corresponds to the extracorporeal circuit of a conventional EBTD, a second circuit is provided which is thermally connected to the first EBTD circuit via a heat exchanger (14) and has temperature influencing means (15). The transfer of thermal energy takes place via the heat-permeable wall of the heat exchanger, which separates the first circuit and the second circuit from one another (indirect heat exchange). In the embodiment shown, the heat exchanger (14) operates according to the countercurrent principle, but the mode of operation with a diffuse flow direction is preferred as well. The temperature influencing means (15) are set up to influence the temperature of the liquid in the second circuit in order to influence the temperature in the first circuit (patient's blood) via heat flow (heat exchanger). The temperature influencing means can have a heating device which is set up to supply thermal energy in the form of heat to the second circuit; alternatively, the temperature influencing means can also have a cooling device which is set up to withdraw thermal energy from the second circuit. In the embodiment shown, the temperature influencing means (15) use a liquid, preferably water, for heating/cooling the liquid of the second circuit; as shown, a reservoir (151) filled with cold water can be connected to the second circuit via switching means (16). A second pump (17) arranged in the second circuit is set up to circulate the liquid in the second circuit. The disclosed EBTD includes a function-monitoring system for determining an indicator of the EBTD function. The system is suitable in particular for monitoring the function of the membrane used for the blood treatment. The functional monitoring system includes a temperature sensor TS2.sub.up arranged in the second circuit upstream of the heat exchanger (14) and a temperature sensor TS2.sub.down arranged in the second circuit downstream of the heat exchanger (14). Furthermore, a temperature sensor TS1.sub.down arranged in the first circuit downstream of the heat exchanger belongs to the functional monitoring system. The terms downstream and upstream relate to the respective flow directions of the first circuit and second circuit in the heat exchanger. If the heat exchanger operates according to the countercurrent principle, the flow directions of the liquids in the first and second circuit are opposite; if the heat exchanger operates according to the cocurrent principle, the flow directions of the liquids in the first circuit and second circuit are the same. In the case of a heat exchanger operating with undirected flow, there is also an upstream input into the heat exchanger and a downstream outlet out of it. In the present embodiment, the temperature sensor TS1.sub.up is arranged in the afferent line (11) of the first circuit upstream of the heat exchanger (14) of the EBTD. The computer system (40) connected to the temperature sensors TS1.sub.down, TS1.sub.up, TS2.sub.down, TS2.sub.up is designed to initiate a temperature bolus in the second circuit of the EBTD by means of the temperature influencing means (15). The computer system (40) is usefully connected to the switching means (16) and the pump (17) of the second circuit. In particular, the computer system can adjust the pump speed to generate a substantially sharp temperature bolus with regard to the heat exchanger. From the temperatures T1.sub.down, T1.sub.up, T2.sub.down, T2.sub.up detected by the temperature sensors TS1.sub.down, TS1.sub.up, TS2.sub.down, TS2.sub.up, a temperature profile can be recorded in a known manner as a function of time and can be evaluated in a respective thermodilution curve. Furthermore, the computer system is designed to use the determined thermodilution curves (TDK) to relate TDK2.sub.down and TDK1.sub.down to one another and to determine an indicator of the EBTD function from the relationship of TDK2.sub.down and TDK1.sub.down. The computer system may further be configured to relate TDK2.sub.up and TDK1.sub.down determined from the thermodilution curves (TDK) and to determine a further EBTD function from the relationship of TDK2.sub.up and TDK1.sub.down. This particular indicator may be corrected by means of a correction factor from the relationship of TDK2.sub.up and the temperature T1.sub.up detected by temperature sensor TS1.sub.up in that the initial temperature gradient between the two circuits is derived from the ratio TDK2.sub.up/TDK1.sub.up and is taken into account for correcting the ratio TDK2.sub.down/TDK1.sub.down.

(4) As shown in FIG. 1, the preferred embodiments also permit the detection of a temperature deviation attributable to the extracorporeal blood treatment device in that the temperature value T1.sub.up measured by the additional temperature sensor TS1.sub.up is related to the TDK1.sub.down generated from the values of the temperature sensor TS1.sub.down.

LIST OF REFERENCE SYMBOLS

(5) 10 Extracorporeal blood treatment device, EBTD 11 Afferent line of the EBTD 12 Efferent line of the EBTD 13 Pump in the first circuit 14 Heat exchanger 15 Temperature influencing means 151 Liquid reservoir, temperature influencing means 16 Switching means 17 Pump in the second circuit