[The reproducibility of stroke-volume measurements by impedance cardiography. A critical analysis (author's transl)].

40 determinations of the stroke volume were carried out by impedance cardiography in one and the same subject. The stroke volume varied between 136 and 209 ml (x, x = 169 ml, S.D. = 17.5 ml). The mean error was in the same range as obtained by the Fick principle or by dye-dilution technique as referred to the literature. However, analysing the factors affecting the variability of the determined stroke volumes we may infer, the Kubicek formula for stroke volume is neither theoretically nor empirically sufficiently proved. A quantitative determination of the stroke volume or of any other circulatory quantity by the impedance cardiography seems to be impossible by our present method of procedure.