Abstract: A respirator with an inhalation line (3), an exhalation line (5) with an exhalation valve (6), with a pressure-measuring device (8) for measuring the airway pressure, and with a circuit (7) for controlling the phases of breathing. The circuit is connected at least to the exhalation valve (6). A rapid reduction in pressure in the breathing gas lines (3, 5) is possible at any time using a control valve (10) in the inhalation line (3) provided with a control pressure space (15) and with a discharge port (19) which can be opened to the environment through a valve element (14). A control pressure line (16), which is branched off from the inhalation line (3) and can be connected to the control pressure space (15), is present. A reversing valve (17) with an evacuation line (18), through which a flow connection can be established between the control pressure space (15) and the evacuation line (18), is arranged in the control pressure line (16).

Abstract: The invention is directed to a controllable expiration valve having a control valve for generating an end expiratory overpressure with the control valve providing the changeable control pressure. The expiration valve is improved so that it is made controllable for compensating dynamic end expiratory overpressure. For this purpose, the membrane chamber of the expiration valve as well as the outflow chamber of the control valve are connected with a device for generating an underpressure.