VERFAHREN UND ANORDNUNG ZUR BESTIMMUNG DER KONZENTRATION VON INHALTSSTOFFEN IN KOERPERFLUESSIGKEITEN

The invention relates to a method and an arrangement for continuously determining the concentration of body fluid constituents, such as glucose or lactic acid. The taking of samples from the body tissue is carried out by the dialysis method. For this purpose, a dialysis probe which can be implanted in body tissue and has the shape of a double-lumen catheter is provided, which in the vicinity of its distal end carries a closed dialysis membrane (26). In addition, a feed channel (12) extending inside the dialysis probe (10) as far as the membrane region and fed with a continuous perfusate stream and also a return channel (18) limited outwardly along one dialysis section by the dialysis membrane (36), communicating with the feed channel at the distal end and connected to a measuring arrangement are provided. In order to be able to carry out drift-free concentration measurements during a measuring period which is as long as possible, the measuring arrangement comprises an electrochemical enzyme cell (20) engaging in a flow chamber of the return channel, while a by-pass channel (24) fed with a buffer stream proportional to the perfusate stream opens into the return channel (18) upstream of the enzyme cell (22) in the direction of flow.