The physiological surveillance of hemodialysis sessions by the continuous measurement of L.F. impedance of the circulating blood (Thomasset's method).

Everybody grants as a fact that hemodialysis disturbances are produced by volemia variations. During H-D the vascular sector is the necessary transit medium to withdraw excessive interstitial water. If this withdrawing is greater than the coming back of the interstitial water into the vascular sector, the plasmatic volume will be decreasing. Thus, to measure the variations of the plasmatic volume in circulating blood it is sufficient to effect a continuous measurement of these ones in a transducer having a definite volume. So, by the mean of an impedancemeter, 5 kHz impedance is continuously measured between the two electrodes of the transducer, because it is known (Thomasset's method) that at 5 kHz current uses only the plasma in order to pass from one electrode to another.