A blood purification apparatus that includes a blood circuit including an arterial blood circuit provided with an arterial puncture needle and a venous blood circuit provided with a venous puncture needle with which an access vessel is puncturable, the blood circuit allowing blood of the patient to extracorporeally circulate; a blood purifier connected to the arterial blood circuit and to the venous blood circuit and that purifies the blood flowing through the blood circuit; a blood pump provided to the arterial blood circuit; a recirculating-blood-detecting unit capable of detecting recirculating blood when the blood of the patient is caused to extracorporeally circulate through the blood circuit by activating the blood pump, the recirculating blood being blood once returned to the patient from the venous blood circuit and reintroduced into the arterial blood circuit; and a recirculation-rate-calculating unit capable of calculating recirculation rate, the recirculation rate being a proportion of the recirculating blood in the blood flowing in the arterial blood circuit. The blood purification apparatus includes a control unit capable of executing a treatment mode in which blood purification treatment is performed with the blood purifier while the blood of the patient is caused to extracorporeally circulate through the blood circuit by activating the blood pump in a state of normal connection where an upstream part of the access vessel is punctured with the puncture needle at a distal end of the arterial blood circuit and a downstream part of the access vessel is punctured with the puncture needle at a distal end of the venous blood circuit; and a measurement mode in which the detection of recirculating blood by the recirculating-blood-detecting unit and the calculation of recirculation rate by the recirculation-rate-calculating unit are performed while the blood of the patient is caused to extracorporeally circulate through the blood circuit by activating the blood pump in a state of reverse connection where the downstream part of the access vessel is punctured with the puncture needle at the distal end of the arterial blood circuit and the upstream part of the access vessel is punctured with the puncture needle at the distal end of the venous blood circuit, the calculated recirculation rate being used in calculating blood flow rate in the access vessel that is calculable in the measurement mode

A control device for a blood treatment machine performs a connection test (50) by causing the blood treatment machine to switch (51, 53) between a first and a second operating state by reversing a blood pump so as to change a flow direction of blood through both a dialyzer and access devices connected to a patient. Based on an output signal of at least one sensor in the blood treatment machine (52, 54), the control device computes (55) an efficiency change parameter that represents a change in in-vivo clearance of the blood treatment machine during the switch of the blood treatment machine between the first and second operating states. The control device evaluates (56) the efficiency change parameter to jointly detect connection errors at the dialyzer, resulting in co-current flow of treatment fluid and blood through the dialyzer, and at the access devices, resulting in access recirculation of blood.

The invention relates to a blood treatment device having an extracorporeal blood circuit which comprises an arterial line, a blood pump, a blood treatment unit and a venous line, wherein the arterial and venous lines can be connected to a blood vessel of a patient, and wherein the blood treatment device has an evaluation and control unit, wherein the evaluation and control unit is configured to carry out the following steps: (a1) determining the blood recirculation in a blood vessel of the patient connected to the extracorporeal blood circuit; and (b) calculating the blood flow in the blood vessel using the blood recirculation determined in accordance with (a1) and using a provided value or a value likewise previously determined for the cardiac output of the patient.

The invention relates to a device for extracorporeal blood treatment, comprising a blood treatment unit 1 that comprises at least one compartment 4. The invention further relates to a method for determining a hemodynamic parameter during an extracorporeal blood treatment by means of an extracorporeal blood treatment device. In order to determine the hemodynamic parameter, the conveying direction of the blood pump 10 is reversed from a normal blood flow to a reversed blood flow. In practice, it has been found that reversing the conveying direction of the blood pump for a measurement for determining a hemodynamic parameter carries the risk of blood clots reaching the patient, despite the dialyser holding back blood clots. The blood treatment device comprises an input unit 23 for inputting a time interval which can be specified by the user, taking into account the patient-specific and system-specific factors. The control and evaluation unit 12 of the blood treatment device is configured such that the operation of the blood pump 10 in the operating mode involving a reversed blood flow is only enabled during the time interval input by means of the input unit, the start of the time interval being determined from the point at which the blood treatment starts.

The invention relates to an apparatus for extracorporeal blood treatment, comprising a blood treatment unit 1 that comprises at least one compartment 3. The invention further relates to an apparatus 15A, 15B for collecting blood clots for a blood line 5, 7 for supplying blood to or removing blood from a blood treatment unit 1 of an extracorporeal blood treatment apparatus, and to a method for determining a hemodynamic parameter during extracorporeal blood treatment using an extracorporeal blood treatment apparatus. In order to determine the hemodynamic parameter, the conveying direction of the blood pump 10 is reversed from a normal blood flow to a reversed blood flow. It has been found in practice that, in the event of a reversal in the conveying direction of the blood pump in order to carry out a measurement for determining a hemodynamic parameter, there is a risk of blood clots reaching the patients, although the dialyser traps blood clots. The apparatus according to the invention provides an apparatus 15A for catching blood clots, at least in the blood line of the extracorporeal blood circuit I that leads to the blood treatment unit 1 during a normal blood flow. The blood treatment unit traps blood clots during blood treatment having a normal blood flow. In the case of a reversed blood flow, the apparatus for catching blood clots in the blood line that leads to the blood treatment unit 1 during a normal blood flow traps blood clots that may have previously accumulated at the inlet of the blood treatment unit.

A device for determining the access flow rate of a patient when connected to a blood treatment machine performs a measurement phase (40), in which the blood treatment machine is caused (41, 43) to operate in first and second operating states, wherein the second operating state at least differs from the first operating state by a change of flow direction of blood or treatment fluid through a dialyzer of the blood treatment machine. Based on sensor values representing a fluid property (42, 44) of the treatment fluid in the first and second operating states, the device computes (45) a measurement value of comparison parameter (e.g. a ratio or a difference) that compares treatment efficiency in the first operating state to treatment efficiency in the second operating state, and determines (46), based on the measurement value, an estimated value of the access flow rate.

A device for determining the access flow rate of a patient when connected to a blood treatment machine performs a measurement phase (40), in which the blood treatment machine is caused (41, 43) to operate in first and second operating states, wherein the second operating state at least differs from the first operating state by a change of flow direction of blood or treatment fluid through a dialyzer of the blood treatment machine. Based on sensor values representing a fluid property (42, 44) of the treatment fluid in the first and second operating states, the device computes (45) a measurement value of comparison parameter (e.g. a ratio or a difference) that compares treatment efficiency in the first operating state to treatment efficiency in the second operating state, and determines (46), based on the measurement value, an estimated value of the access flow rate.

Techniques and apparatuses for access recirculation of a patient during dialysis treatment are described. In one embodiment, for example, an apparatus may include at least one memory, and logic coupled to the at least one memory. The logic may be configured to determine a first hemoglobin concentration for a dialysis system, determine a change in an ultrafiltration rate, determine a second hemoglobin concentration modified due to the change in the ultrafiltration rate based on a dialysis system model of the dialysis system, and determine an access recirculation value for the dialysis system. Other embodiments are described.

The invention relates to dialysis device having an extracorporeal blood circuit which has an arterial line having a blood pump and an arterial needle for connection to a patient, a venous line having a venous needle for connection to a patient and a dialyzer arranged between the arterial line and the venous line and having a blood chamber and a dialysis fluid chamber, wherein the dialysis device furthermore has a control unit, wherein the dialysis device furthermore has an extracorporeal blood pressure sensor which is arranged at the suction side of the blood pump and wherein the control unit is configured such that a signal output takes place which indicates the presence of recirculation when a change in the signal of the sensor following a trigger event exceeds a threshold value.

An object is to provide a blood purifying device and an access flow rate measuring method enabling easy and accurate measurement of an access flow rate of an access vessel. A blood purifying device includes a flow rate calculating unit calculating the access flow rate of an access vessel based on an initial blood indicator for blood distributed through a vein side circuit and flowing through the access vessel of a patient, the flow rate distributed through measuring means when a pump is reversed to cause the priming solution to flow out from an artery side circuit, and a blood indicator for the blood diluted with the priming solution which is obtained when the pump is reversed to dilute, with the priming solution, the blood distributed through the vein side circuit.