The invention relates to a portable ultrafiltration device comprising a suction bellows (9) connected by means of a tube (8), passing through a solenoid valve (10), to one of the dialysate connectors of a hemofilter (1) incorporated into a blood circuit made up of arterial lines (2), extending from a vascular access (4) and passing through a peristaltic pump (5), and venous lines (3) passing through an electronic safety block (6) and connecting to the vascular access (4), while the other dialysate connector is connected to an ultrafiltration pressure sensor (7). The peristaltic pump (5), the electronic safety block (6), the ultrafiltration pressure sensor (7) and the solenoid valve (10) are connected and controlled by means of an intelligent central unit (11) powered by a rechargeable battery. The patient's blood flows through the blood circuit and the negative pressure generated by the suction bellows (10) is transmitted through the connection tube (8) and causes the ultrafiltration of the blood through the fibres of the hemofilter (1). In this way, liquid collects in the space surrounding the fibres and in the suction bellows (9) until the space is completely full. As the suction bellows (9) fills, the negative pressure exerted thereby decreases to zero and subsequently increases slowly until it reaches the level of the pressure in the blood contained in the fibres. At that moment, the ultrafiltration stops and the central unit (11) indicates to the user that the treatment is finished by means of a visual or audible alarm. The blood is returned to the patient by means of the infusion of an isotonic physiological solution. The hemofilter (1) and the suction bellows (10) are then removed from the device.L'invention concerne un dispositif portable pour ultrafiltration qui comporte un soufflet aspiratif (9) relié par une tubulure (8) passant à travers une électrovanne (10) à l'un des embouts dialysat d'un hémofiltre (1) intégré dans un circuit sanguin fait lui-même de
