Fluid volume monitoring with electrical impedance technique during hemodialysis.

A tetrapolar whole-body impedance technique has been developed for bedside monitoring of fluid volume changes during hemodialysis. A microprocessor is utilized for control and calculations. Recorded values of fluid volume changes for 10 patients were compared to concomitant changes in weight. A linear relationship with a correlation coefficient of r = 0.89 was obtained. Fluid volume changes as small as 0.1 L could be detected.