The biomedical appliance (1), comprises: - a device (2) for the oxygenation of blood having at least an inlet fitting and at least an outlet fitting for blood - a circuit (20) for the pre-filling of the device (2) for the oxygenation - at least a bag (21) for containing a liquid substance having at least a first and a second mouths, distinct from one another, to allow the liquid substance to come out and reinfuse, respectively where the circuit (20) comprises: - at least a supply line (22) communicating on one side with the first mouth of the bag (21) and on the other side with the inlet fitting of the device (2) for the oxygenation - manual pumping means (24) arranged along the supply line (22) and which can be operated to suction the liquid substance from the bag (21) and to convey the liquid substance suctioned this way into the device (2) for the oxygenation - valve means (25, 26) arranged along the supply line (22) and which can be operated during the suction and conveying of the liquid substance to prevent at least the substance itself from flowing from the device (2) for the oxygenation towards the pumping means (24) and from the latter towards the bag (21), respectively - at least a return line (27), distinct from the supply line (22), communicating on one side with the outlet fitting of the device (2) for the oxygenation and on the other side with the second mouth of the bag (21), the return line (27) being suitable for reintroducing the liquid substance that comes out of the device (2) for the oxygenation, along with the air contained in same, inside the bag (21).Linvention concerne un appareil biomédical (1), qui comprend : - un dispositif (2) doxygénation du sang ayant au moins un raccord dentrée et au moins un raccord de sortie pour le sang - un circuit (20) pour le préremplissage du dispositif (2) doxygénation - au moins un sac (21) pour contenir une substance liquide ayant au moins des première et seconde embouchures, distinctes lune de lautre, pour
