Patent ID: 8852135

Claim:
A method for checking a supply of substitution fluid for an extracorporeal blood treatment apparatus that includes (a) an extracorporeal blood circuit having an arterial blood line, which leads from an arterial patient connection to a first chamber of a dialyzer or filter divided by a membrane into the first chamber of the dialyzer or filter and a second chamber, and a venous blood line, which leads from the first chamber of the dialyzer or filter to a venous patient connection, (b) a substitution fluid supply line configured to supply substitution fluid at an arterial admission point upstream of the dialyzer or filter, wherein substitution fluid is fed to the extracorporeal blood circuit for a pre-dilution, and/or at a venous admission point downstream of the dialyzer or filter, wherein substitution fluid is fed to the extracorporeal blood circuit for a post-dilution, (c) a blood pump configured to convey blood in the extracorporeal blood circuit, and (d) a bubble trap disposed in the venous blood line, comprising: filling a part of the extracorporeal blood circuit that lies between the arterial patient connection and the arterial admission point of the extracorporeal blood circuit with a fluid; feeding the fluid to the extracorporeal blood circuit via the substitution fluid line connected either to the arterial admission point or the venous admission point until a predetermined fluid level has become established in the bubble trap; putting the blood pump configured to convey the fluid in the extracorporeal blood circuit into operation; monitoring the fluid level in the bubble trap; and determining, based on the monitoring, that (a) there is a connection of the substitution fluid line to the arterial admission point when the fluid level in the bubble trap does not fall below the predetermined fluid level or (b) there is a connection of the substitution fluid line to the venous admission point when the fluid level in the bubble trap falls below the predetermined fluid level.