Patent ID: 7699992

Claim:
A method for determining at least one patient or treatment or apparatus parameter during an extracorporeal blood treatment carried out by an extracorporeal blood treatment apparatus, in which at least a first liquid is circulated towards at least a portion of said extracorporeal blood treatment apparatus, and at least a second liquid flows from said extracorporeal blood treatment apparatus portion, said method comprising: altering at least one physical or chemical characteristic of said first liquid according to an altering function determined or predetermined as a function of at least a mathematical model of at least a part of said extracorporeal blood treatment apparatus portion; measuring at least one value of at least one physical or chemical characteristic of said second liquid, said second liquid characteristic being changed in response to said alteration of said first liquid characteristic; and evaluating at least one patient or treatment or apparatus parameter from at least said at least one measured value of said second liquid characteristic wherein said mathematical model comprises a first transfer function that describes a process dynamics of at least a part of said extracorporeal blood treatment apparatus portion, said response to said alteration of said first liquid characteristic being correlated to said process dynamics.