The apparatus (1) for the decapneization of blood, comprises: - a supply line (2) of the blood to be treated taken from a patient and at least a return line (5) adapted to transport the treated blood to the patient - at least an oxygenation device (3) and at least a filtering device (4) of the blood positioned between the supply line (2) and the return line (5) where the supply line (2) comprises a main section (2a), connectable on one side to the patient and connected on the opposite side to the oxygenation device (3), and a by-pass section (2b), arranged parallel to the main section (2a) and along which the filtering device (4) is arranged, wherein the by-pass section (2b) comprises a delivery branch (6), connected on one side to the main section (2a) and on the other side to the input of the filtering device (4), and a return branch (7), connected on one side to the output of the filtering device (4) and on the other side to the main section (2a), and wherein it comprises removable connection means (10), arranged along the branches (6, 7) and adapted to allow the separation of a first portion (11) of the branches themselves which is connected to the filtering device (4), from a respective second portion (12) connected to the main section (2a), the second portions (12) being connectable to each other by means of the connection means themselves following the separation from their respective first portions (11).
