Patent ID: 6767333
Filing Date: 2004-07-27
Classification: A61M

Abstract:
A method of increasing the safety of an extracorporeal blood treatment machine of the type that includes an exchange unit divided into first and second chambers by a semipermeable membrane, and an ultrafiltration device adapted to remove ultrafiltrate from the exchange unit at an ultrafiltration rate, wherein the ultrafiltration device includes a means for adjusting the ultrafiltration rate which can be varied during a blood treatment, the method comprising the steps of:varying the ultrafiltration rate during the blood treatment; continuously calculating a transmembrane pressure TMPc at a preset ultrafiltration rate UFR from the quotient of the preset ultrafiltration rate UFR and an ultrafiltration coefficient UFK; continuously calculating at least one of an upper limit transmembrane pressure L1 and a lower limit transmembrane pressure L2 on the basis of the calculated transmembrane pressure TMPc, wherein the upper limit transmembrane pressure L1 and the lower limit transmembrane pressure L2 are calculated as a function of the ultrafiltration rate; measuring a transmembrane pressure TMPm of the exchange unit, and comparing the measured transmembrane pressure TMPm with the at least one of the upper limit transmembrane pressure L1 and the lower limit transmembrane pressure L2.