[Continuous measurement of blood volume changes in hemodialysis using an ultrasound method]

Haemodialysis treatment comprises the removal of surplus body water, mainly by ultrafiltration. Frequent complications, such as hypotension, are believed to be related to an imbalance between blood volume reduction, based upon ultrafiltration, and vascular refilling. The control of fluid balance can be achieved by the measurement of blood volume changes. A new method of determining total blood protein concentration by ultrasonic means facilitates continuous monitoring of blood volume changes during haemodialysis. Blood volume monitoring was undertaken during 38 haemodialysis treatments (19 patients) in order to achieve a better adjustment of the patient's estimated dry weight. The relative change in blood volume was registered in 11 patients who were first ultrafiltrated to their estimated dry weight. In a following session the ultrafiltration was increased by 10%. The relative change in blood volume, normalized to the change in total body water, increased significantly from 1.16 +/- 1.11% (normal ultrafiltration) to 1.67 +/- 0.8% (normal ultrafiltration + 10%) (p less than 0.05). Thus, normalized blood volume reduction may serve as an approximation to adjust the patient's dry weight.