A device analyzes an anesthesia ventilation gas with an infrared radiation source and includes a gas cuvette, a Fabry-Perot interferometer with a band pass filter function, adjustable with respect to a central transmission wavelength as a function of a control signal, a detector providing a measured signal and a computing and control unit providing the control signal and detecting the measured signal. The computing and control unit is configured to actuate the Fabry-Perot interferometer in a first operating mode by the control signal such that the central transmission wavelength scans a predefined wavelength range, to detect a presence in the ventilation gas sample potential types of anesthetic gases based on the measured signal. In a second operating mode, the control unit controls the central transmission wavelength within a subrange of the predefined wavelength range and determines a plurality of concentration values at consecutive times for detected types of anesthetic gases.