The present invention relates to a device (1) for the catalytic decomposition of nitrous oxide in a gas stream derived from exhaled breath from a patient. The device (1) comprises an inlet facility (2) with a gas inlet (3) for exhalation, an outlet facility (11) with a gas outlet (12) for exhaust gas, and catalytic material between these facilities. A through-flow decomposition chamber (9) including According to the invention, the device is equipped with nitrous oxide adsorption/desorption means (4) at the inlet facility (2) in order to level the fluctuations in the concentration of nitrous oxide fed to the decomposition chamber (9). [Selection diagram] Figure 1本発明は、患者からの呼気に由来するガス流中の亜酸化窒素の触媒的分解のための装置（１）に関する。装置（１）は、呼気用のガス入口（３）を備えた入口設備（２）、排出ガス用のガス出口（１２）を備えた出口設備（１１）、及びこれらの設備の間の触媒材料を含むスルーフロー分解室（９）を備える。本発明によれば、分解室（９）に供給される亜酸化窒素の濃度の変動を平準化するために、装置は入口設備（２）に亜酸化窒素吸着／脱着手段（４）を備える。【選択図】図１
