Apparatus, sensor and process for determining at least one parameter of blood circulating in an extracorporeal blood circuit

An apparatus for extracorporeal blood treatment comprising:

• a non-invasive sensor for determining a blood parameter selected from plasma conductivity and sodium concentration in the blood of blood flowing in a tube segment of an extracorporeal blood treatment apparatus comprising:
• at least one source for directing a signal towards the blood along an emission axis, wherein the source includes one of either an electromagnetic radiation emitter, or an ultrasound emitter,
• a plurality of detectors for receiving the signal emitted by the at least one source after at least partially passing through the blood flowing in the segment and emitting respective output signals related to the received signal,
• a controller configured for receiving the respective output signals from the plurality of detectors and for determining a value or a time variation of the blood parameter based on the output signals emitted by the plurality of detectors, wherein the controller is further configured for:
• receiving values of at least one of a sodium concentration and of a conductivity of an inlet dialysis fluid flowing in a preparation line of the extracorporeal blood treatment apparatus,
• receiving values for a conductivity of an outlet dialysis fluid flowing in a spent dialysate line of the extracorporeal blood treatment apparatus, and
• determining the value of the blood parameter based on the output signals emitted by the plurality of detectors, the outlet dialysis fluid conductivity, and at least one of the inlet dialysis fluid sodium concentration and the inlet dialysis fluid conductivity,
• an extracorporeal blood circuit including a treatment unit, a withdrawal line connected to an inlet of the treatment unit, and a return line connected to an outlet of the treatment unit, the extracorporeal blood circuit comprising an extracorporeal segment, the extracorporeal segment being a tube segment,
• a holder of the extracorporeal blood circuit, and
• a control unit for driving the extracorporeal blood treatment apparatus,
• wherein the apparatus comprises the extracorporeal blood circuit mounted on the holder and with the tube segment received by the non-invasive sensor, wherein the tube segment is a tubular segment of the blood withdrawal line or of the blood return line and wherein, in an operative condition, the sensor is positioned about and in contact with an external surface of the tube segment of the extracorporeal blood circuit.