Measurement of Fluid Volume Shifts during Hemodialysis by A-Mode Ultrasonography

Abstract

BACKGROUND: The rate of intercompartmental fluid volume changes during hemodialysis (HD) is a major determinant of dialysis-induced hypotension and lacks direct monitoring. The aim of the study was to evaluate the feasibility of tissue thickness (TT) measurement in monitoring the mobilization of interstitial fluids during HD. METHODS: We studied the intradialytic changes in forehead TT and inferior vena cava diameter (IVCD) in 20 patients. Plasma refilling was calculated from changes in hematocrit (Hct) and ultrafiltration rates. RESULTS: During ultrafiltration of 2,437 +/- 117 ml (mean +/- SEM), Hct increased significantly from 27.9 +/- 0.7 to 30.0 +/- 0.9%. IVCD decreased significantly from 9.7 +/- 0.2 to 6.1 +/- 0.4 mm/m(2). We found a simultaneously pronounced reduction in TT from 4. 46 +/- 0.12 to 3.78 +/- 0.12 mm (> or =15.3%) with a significant correlation to plasma refilling (0.613). CONCLUSION: Volume changes in the peripheral shell tissues during HD can be monitored directly and noninvasively by A-mode ultrasound.