Patent ID: 12257033

DESCRIPTION OF NON-LIMITING EMBODIMENTS OF THE DISCLOSURE

FIG.1shows a schematic overview of an aspect of the disclosed measuring arrangement and the vascular system of a patient, wherein the apparatus for extracorporeal blood treatment (10) is connected to the venous vascular system of the patient via an inflow line (11; “drainage”) and an outflow line (12). The extracorporeal blood treatment apparatus can be, for example, an apparatus for extracorporeal membrane oxygenation (vvECMO, as shown inFIG.1) or an apparatus for liver dialysis. The inflow line (11) is introduced, for example, via the femoral vein and comes to rest in the inferior vena cava (V. cava inferior) below the convergence of the hepatic vein. The outflow line (12) is introduced, for example, via the jugular vein and comes to rest in the superior vena cava (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 apparatus via the inflow line (11), while the oxygenated blood reaches the right atrium via the outflow line (12). The inventive system can also be used in situations in which a vaECMO is used, in which the deoxygenated blood is conducted via the femoral vein to the ECMO and the oxygenated blood is returned to the vascular system of the patient via the femoral artery. In this arrangement, the ECMO takes over the entire pumping output.

The cardiovascular parameter is determined by means of thermodilution; several cardiovascular parameters can also be determined and/or calculated by means of thermodilution. The disclosed temperature influencing means (20) are preferably an injection device by means of which a cooled liquid is injected as a bolus into the vascular system of the patient. In principle, the temperature change can be generated at any point in the central venous vascular system of the patient. The outflow line of the ECMO (via which oxygenated blood is supplied to the vascular system of the patient) and the first point (31) are preferably cranial with respect to the plane of the heart valve. As shown inFIG.1, it is particularly preferred to perform a bolus injection for the thermodilution measurement at a first point (31), e.g., the jugular vein, upstream of the inflow line (11) of the ECMO. A traveling temperature change generated in the jugular vein travels via the right heart and pulmonary circulation into the left heart and from there via the aorta into the systemic circulation. The initial temperature deviation T1generated by the bolus injection is calculated or measured, e.g., using a corresponding algorithm. The temperature influencing means can preferably detect the temperature, time, and possibly also duration of the bolus injection, for example by means of a temperature sensor which is arranged within or in the immediate vicinity of the temperature influencing means. The temperature influencing means can preferably supply the measurement results to a computer system (40) which is connected to the disclosed system via connecting means. The first temperature sensor (21) for measuring the local temperature of the blood of the patient is arranged at a second point (32) of the vascular system of the patient, downstream of the first point (31), in this case e.g., in the femoral artery. A further temperature sensor (22) is arranged in the inflow line (11) of the extracorporeal blood treatment apparatus. Depending on the flow rate of the extracorporeal blood treatment apparatus, e.g., at a high flow rate>500 mL/min, or depending on the pointal relationship between the injection site/inflow to the line, a part of the injected temperature bolus branches off into the extracorporeal circuit. This part of the injected temperature bolus is recorded by the second temperature sensor (22). The computer system (40) connected to the first (21) and second temperature sensor (22) via connecting means records the detected temperature as a function of time and correspondingly determines a first and a second thermodilution curve (TDK1, TDK2). The technical program device for carrying out evaluation steps of a thermodilution is known per se from the prior art (e.g., from German laid-open specification DE 4 214 402 A1). The computer system is furthermore configured to determine from the second thermodilution curve TDK2a temperature deviation TEKBVwhich is to be allocated to the extracorporeal blood treatment apparatus, and T1and TEKBVfor determining the cardiovascular parameter. The system of the present disclosure advantageously enables an indicator loss, possibly caused by the extracorporeal circuit, to be detected and subsequently corrected so that errors in the determination of cardiovascular parameters, such as, e.g., the CO, during an extracorporeal blood treatment, e.g., during ECMO treatment, can be minimized and thus the accuracy and reliability of the determination is increased. The system of the present disclosure can be used independently of the arrangement/flow direction of the specific extracorporeal blood treatment apparatus and is therefore versatile. The patient is better integrated into the extracorporeal blood treatment apparatus and the configuration of the latter is optimally adjusted to the cardiovascular condition of the patient.

In a further embodiment of the system of the present disclosure, the first point of the vascular system of the patient, in the vicinity of which point the temperature influencing means cause the initial local temperature deviation T1, can be located in the vicinity of a first point of the vascular system of the patient upstream of the inflow line (11) of the extracorporeal blood treatment apparatus. The term “upstream” refers to the direction of flow in the inflow line of the blood treatment apparatus. For example, the inflow line of the blood treatment apparatus can be located in the inferior vena cava, while the temperature deviation is caused in the jugular vein. The arrangement leads to the least possible interference by the system of the present disclosure in the extracorporeal blood treatment apparatus, so that, e.g., the number of measurement cycles required is advantageously kept low.