[The respirophonogram as a means of drug screening (author's transl)]

Respirophonography is an objective method of measuring respiratory and adventicious sounds. Current techniques make a perfect, albeit somewhat tedious registering of these respiratory murmurs possible, which can then be analysed for frequency. In this paper the method is investigated for its applicability to drug screening and proved satisfactory in a double blind trial and a pilot study. During treatment with secretolytic drugs the pathological respiratory sounds change or cease. In the respirophonogram this is recognisable by the fact that the volume peaks are either displaced to another frequency area or that they disappear altogether. The frequency range 100--500 Hz is the most significant as far as the respiratory murmurs are concerned. The concepts familiar to the clinician experienced in auscultation are set out in an unaccustomed way in the frequency-volume diagram. The respirophonogram offers the advantage that it can be documented and that findings can therefore be compared objectively. From the point of view of the clinician respirophonography is despite its far reaching perfection already attained, still technically in a preliminary stage.