Patent ID: 9364598
Filing Date: 2016-06-14
CPC Classification: A61B,A61M

Claim Text:
1. A method of determining fistula recirculation for a device for the extracorporeal treatment of blood, wherein the device for the extracorporeal treatment of blood comprises an extracorporeal blood circuit including a first chamber of a dialyser or a filter, and a fluid system including a second chamber of the dialyser or the filter, wherein the dialyser or the filter is divided by a semipermeable membrane into the first chamber and the second chamber, and wherein substitution fluid is supplied to the extracorporeal blood circuit upstream or downstream of the dialyser or the filter by means of a substituate pump, the method comprising: at least one of starting up the substituate pump which has been previously shut off, or shutting off the substituate pump which has been previously started up; measuring a pressure in the extracorporeal blood circuit upstream of the dialyser or the filter and downstream of the dialyser or the filter after the at least one of starting up the substituate pump which has been previously shut off, or shutting off the substituate pump which has been previously started up; and determining fistula recirculation by calculating the ratio between the integral of the pressure measured upstream of the dialyser or the filter in a predetermined time interval in which a repeating positive and/or negative pressure pulse occurs, and the integral of the pressure measured downstream of the dialyser or the filter in a predetermined time interval in which a repeating positive and/or negative pressure pulse occurs.