A fluid interface device for delivering fluid to and/or withdrawing fluid froma patient, the device comprises aperipheral base element (2) and a fluid transmission element (4) sealinglyconnected to the base element and forming a central portion ofthe device. The fluid transmission element comprises a front platelet (6) witha primary face (8) and a secondary face (10) opposedthereto, the primary face being in contact with a patient's body fluid region(12) when the device is implanted in the patient, the fluidtransmission element further comprising a counterplate (14) sealingly stackedagainst the secondary face of the front platelet andforming a buffer volume (16) therebetween. The front platelet comprises atleast one array of microchannels (18) defining a fluidpassage between the buffer volume and the primary face, the microchannelshaving an opening of 0.2 to 10 µ.eta..iota.. The counterplate hasat least one fluid port (20； 20a, 20b) for fluid delivery to and/or fluidwithdrawal from the buffer volume.
