The trachea cannula has an air opening (21) shaped such that an initial opening edge zone (20) is at the endotracheal side of the cannula (1). The opening is outside a sealing surface (18) between the inner wall of the trachea tube (1) and the barrier. A second edge zone (24) of the opening, at the exotracheal side, extends to the sealing surface (18), so that the trachea cannula (1) can be closed effectively.
