A driver warning device which serves to warn the driver when a safety-critical condition of the vehicle is reached. An exemplary embodiment includes storing a plurality of associations, each association between a route taken by a user and user characteristics. In the controlling entity, the messages are controlled before being transmitted to the network. The blood or plasma is, thus, exposed to two microporous hollow fibers which have fluids which can purify or otherwise affect the blood through the walls of two different microporous hollow fibers.