Abstract: An anesthetic machine, in particular for use as ventilation part of an anesthetic system which has an inspiratory and an expiratory branch. In order to reuse, e.g. in a half-closed anesthetic system, part of the exhaled gas, the expiratory branch is connected via an additional line to the inspiratory branch. In addition, a controllable inspiration valve is used to control the respiratory gas removed from a gas store.

Abstract: With closed respiratory systems, the patient's respiratory tract is tightly connected to a closed volume to which breathing gas is supplied only in the amount taken in by the patient. To this end, the breathing gas supply must be controlled. The controlled variable is either the pressure in the ventilating circuit, or the concentration of oxygen or the anesthetic gas in the breathing gas. A dropping pressure indicates either an increased consumption or a leak. To avoid insufficient or excessive loading of the patient, it is very important to be able to distinguish consumption from a leak. The inventive device makes this distinction possible. The breathing gas amounts are adjusted in the ventilating circuit at preset different pressures and are compared with each other, and the leak portion is computed therefrom.