VOLUME-DEPENDENT ECHOCARDIOGRAPHIC PARAMETERS ARE NOT USEFUL FOR ESTIMATING BASE-LINE BLOOD-VOLUME BUT ARE USEFUL FOR DETECTING ACUTE CHANGES IN VASCULAR FILLING STATE

To assess the hypothesis that echocardiographic variables vary as a fu nction of baseline blood volume and change in response to changes in v ascular filling state, we evaluated the relationship between the atria l and ventricular dimensions and left ventricular function, as measure d by combined Doppler and M-mode echocardiography on the one hand, and blood volume as measured by a standard radioactive isotope technique on the other. Furthermore, we determined the effect of an increment in vascular filling state induced by plasma volume expansion. Test subje cts were ten male and six female volunteers. Blood volume/kg was the o nly factor not different between male and female subjects and therefor e suitable for our study. None of the echocardiographic variables corr elated with blood volume/kg. Volume loading increased stroke volume, l eft atrial diameter, right atrial area, left ventricular enddiastolic dimension, mean velocity of circumferential fiber shortening and left ventricular ejection time. It is concluded that echocardiographic vari ables are unsuitable for estimating blood volume. Serial measurements of atrial dimensions and left ventricular dimensions are useful for de tecting rapid changes in vascular filling state.