A method for continuously determining a parameter (D, Cbin, K, Kt/V)
indicative of an extracorporeal blood treatment includes flowing patient's
blood and a treatment liquid flow on opposite sides of a semipermeable
membrane. The treatment liquid has a characteristic (Cd) associated with
the effectiveness of the treatment flow through the exchanger. A
succession of variations are caused in the characteristic (Cd) upstream of
the exchanger, and a plurality of values (Cdin1 . . . Cdinj . . . Cdinp)
of the characteristic (Cd) upstream of the exchanger are continuously
stored in memory. Similarly, plurality of values (Cdout1 . . . Cdoutj . .
. Cdoutp) adopted by the characteristic (Cd) downstream of the exchanger
are continuously stored in memory. From the stored values, the
effectiveness of the treatment is calculated using a mathematical model.
