Patent ID: 7141023

Claim:
A micro perfusion device comprising a collecting container, for obtaining at least one constituent of a body fluid using a subcutaneously positioned perfusion cannula, said device comprising: a) a casing; b) a perfusate supply; c) an inner cannula, forming an inner lumen between a front cannula opening which is distal when the device is subcutaneously positioned and a rear cannula opening, said inner lumen being connected or connectable to said perfusate supply via said rear cannula opening, said inner cannula being accommodated by said casing so as to be slidable in the longitudinal direction from a front sliding position to a rear sliding position and said rear cannula opening being formed in a surface area of said inner cannula; d) a sealing ring surrounding said inner cannula in said casing under pressure and, in said rear sliding position of said inner cannula, pre-latching into said rear cannula opening; e) a perfusion cannula, projecting from a lower side of said casing and surrounding said inner cannula, an outer lumen remaining between said inner cannula and said perfusion cannula; f) a collecting container for said perfusate; and g) an outlet for said perfusate, connecting said outer lumen to said collecting container; wherein said collecting container is a variable-volume collecting container and a partial vacuum with respect to a pressure prevailing in said perfusate supply is generated in said collecting container.