Device and Method for Detecting the Recirculation During An Extracorporeal Blood Treatment

摘要

A device and method for detecting recirculation for an extracorporeal blood treatment apparatus and an apparatus with a device for detecting recirculation are based on targeted haemodilution by administration of a substituate bolus, causing a pressure change in venous and arterial branches of the extracorporeal circuit due to a viscosity change of flowing fluid. Recirculation is detected based on detection of the pressure change. The device includes a control unit cooperating with a device for conveying blood and a device for supplying substituate. The control unit provides an operating mode for detecting recirculation, in which blood flow rate is reduced during administration of a substituate bolus. With simultaneous substituate bolus administration and reduction of blood flow rate, the composition of fluid flow is optimised for detection of recirculation, so that fairly large pressure changes result in venous and arterial branches, thereby improving sensitivity and reliability of the measurement method.

主权项

1. A device for detecting recirculation for an extracorporeal blood treatment apparatus, the extracorporeal blood treatment apparatus comprising an extracorporeal blood circuit with an arterial blood line, which leads to a first chamber of a dialyser or filter divided by a membrane into the first chamber and a second chamber, and a venous blood line, which leads away from the first chamber of the dialyser or filter, a fluid system, which comprises the second chamber of the dialyser or filter, a device for conveying blood at a preset blood flow rate Qb through the arterial blood line into the first chamber of the dialyser or filter and through the venous blood line from the first chamber of the dialyser or filter, and a device for supplying substituate to the blood at a preset substituate rate Qs in the arterial blood line upstream of the dialyser or filter, the device for detecting the recirculation comprising:
a measuring unit adapted for measuring pressure in the extracorporeal circuit in the arterial and/or venous blood line, an evaluation unit adapted for detecting the recirculation based on the pressure measurement, and a control unit cooperating with the device for conveying blood and the device for supplying substituate, the control unit being adapted, in an operating mode for detecting the recirculation, to control the device for conveying blood such that in a preset time interval, a preset first blood flow rate Qb1 is reduced to a preset second blood flow rate Qb2, and to control the device for supplying substituate such that in the preset time interval, substituate is fed at the preset substituate rate Qs to the blood in the arterial blood line upstream of the dialyser or filter, wherein the evaluation unit is adapted to monitor the pressure measured by the measuring unit in the arterial and/or venous blood line for a change in the pressure.