Patent ID: 11883571
Assignee: GAMBRO LUNDIA AB
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 7:
8. The method according to claim 1, further comprising measuring at least the initial parameter value of the dialysate in the dialysis effluent line downstream of the secondary chamber as soon as the exchange process in the filtration unit reaches stable conditions, the method determining that stable conditions for the exchange process have been reached when one or more of the following conditions occurs:
a first derivative of a median or average value of the conductivity of the dialysate is lower than a first threshold for a specified time window,
a first derivative of a value of conductivity of the dialysate is lower than a first threshold for a specified time window,
a first derivative of a filtered value of conductivity of the dialysate is lower than a first threshold for a specified time window, the filtered value being a value filtered either by a median filter, a linear filter, a finite impulse response filter, or an infinite impulse response filter,
a second derivative of the median or average value of the conductivity of the dialysate is lower than a second threshold for a specified time window,
a second derivative of the value of conductivity of the dialysate is lower than a first threshold for a specified time window,
a second derivative of the filtered value of conductivity of the dialysate is lower than a first threshold for a specified time window,
a change or a relative change of the value of conductivity of the dialysate or a filtered version of the value of the conductivity with respect to a fixed previous point in time is below a first threshold;
a change or a relative change of the value of conductivity of the dialysate or a filtered version of the value of the conductivity with respect to a fixed time interval backwards is below a first threshold,
a prefixed time has lapsed after starting circulation of both blood and dialysis fluid in the filtration unit, the pre-fixed time being not more than fifteen minutes, or
a variable time has lapsed after starting circulation of both blood and dialysis fluid in the filtration unit, the variable time being a function of at least a parameter of the apparatus,
wherein during the step of determining the reaching of stable conditions, the method includes preventing changes in a dialysis fluid flow rate.