Method of detecting recirculation in an arteriovenous shunt during ongoing hemodialysis and dialysis system

摘要

Control methods of a dialysis machine for allowing the dialysate-side detection of a recirculation in an arteriovenous shunt of a patient during ongoing hemodialysis are described. A sensor is arranged downstream of a dialyzer and detects a change of a physicochemical parameter PD of outflowing dialysis fluid. Control elements are provided to guide the dialysis fluid in a selected manner through the dialyzer or pass it by. Recirculation may be determined by passing the dialysis fluid by the dialyzer so that the dialysis fluid is guided unchanged along the sensor for calibration, switching the control elements after optional sensor calibration such that the dialysis fluid flows through the dialyzer, and adjusting a desired first blood flow value BF1 in the blood-side extracorporeal circulatory branch so that between an inlet of the extracorporeal circulatory branch and an outlet a recirculation R and, a first clearance K1 are adjusted and the parameter detected by the sensor adopts a corresponding value PD1, changing the first blood flow value BF1 to a second blood flow value BF2, wherein a second clearance K2 is adjusted, and accordingly at the sensor a new parameter value PD2 is provided and detected, and determining the recirculation R by the course of change from the parameter value PD1 to the parameter value PD2.

主权项

1. A control method of a dialysis machine to allow detection on the dialysis fluid side of recirculation in an arteriovenous inlet/outlet element, preferably a shunt, wherein the dialysis machine comprises at least one dialysis fluid inlet and at least one dialysis fluid discharge for a selected dialysis fluid and at least one dialysis fluid pump which are in fluidic communication with at least one dialyser, wherein, viewed in the dialysis fluid flow direction, a sensor is arranged downstream of the dialyser and detects a change of a physicochemical parameter (PD) of the outflowing dialysis fluid,the method comprising the steps of:
setting a desired first blood flow value BF1 at which recirculation R>/=0 is adjusted and the parameter detected by the sensor adopts an appropriate value PD1; changing the first blood flow value BF1 to a preferably lower second blood flow value BF2, wherein at the sensor a new parameter value PD2 is appropriately provided and detected; determining recirculation R by way of the course of change and/or the change from the parameter value PD1 to the parameter value PD2; wherein the physicochemical parameter PD is an optical absorption, and wherein an absorption in the IR wavelength range, UV wavelength range or in the visible wavelength range, or an absorbance is utilized.