Abstract: For the measurement of functional respiratory volume, or respiratory capacities, apparatus are known including a respiratory bag which can be connected to a respiratory tube via a first valve system and which can be connected to test gas receptacles via an additional valve system and which exhibit gas analysis devices for measurement of the test gas concentration in the respiratory bag. Precise concentration measurements have been hitherto possible only discontinuously with chemical methods, or continuously with a large apparatus outlay (mass spectrometer). By way of a contrast, simple thermal conductivity sensors are unsatisfactory in measuring precision.

Abstract: An apparatus for the determination of the respiratory passageways resistance, including a flow resistance in the breathing or respiratory flow passageway, whose resistance value is periodically varied by a frequency which lies above the breathing frequency, and including as well a pressure and/or, as occasioned, a flow measurement gauge. In conjunction with the flow resistance, the resistance value thereof is varied in an essential sinusoidal manner, and the pressure and/or flow measurement gauge incorporates two measuring passageways, there being detected in the first passageway only the pressure and/or occasioned flow components in the respiratory passageway due to the lower frequencied breathing, and in the second passageway the higher frequencied resistance variations.

Abstract: An apparatus for the determination of the respiratory passageway resistance, including a breathing tube which incorporates a flow resistance and a pulse generator for subjecting the breath flow to higher frequency pressure or, respectively, current pulsations, as well as a pressure gauge for measuring the pressure in the breathing tube. The pressure gauge is constituted of an alternating pressure gauge coordinated with the pulsating frequency of a pulse generator. As alternating pressure gauge there may be utilized a common mechanical-electrical transducer which, for detection of the alternating pressure, has an electrical frequency filter connected thereto.

Abstract: An apparatus for the determination of the respiratory passageway resistance. Apparatus of that type in general evidence a flow resistance located in the respiratory passageway, whose resistance value is periodically varied at a frequency which is located above the breathing frequency, or a breathing tube with a flow resistance and a pulse generator for subjecting the breath flow with higher-frequencied pressure- or, respectively flow pulsations.

Abstract: An apparatus for the determination of the respiratory passageways resistance, including a flow resistance in the breathing or respiratory flow passageway, whose resistance value is periodically varied by a frequency which lies above the breathing frequency, and including as well a pressure and/or, as occasioned, a flow measurement gauge. In conjunction with the flow resistance, the resistance value thereof is varied in an essential sinusoidal manner, and the pressure and/or flow measurement gauge incorporates two measuring passageways, there being detected in the first passageway only the pressure and/or occasioned flow components in the respiratory passageway due to the lower frequencied breathing, and in the second passageway the higher frequencied resistance variations.