Measurement of anterior-posterior diameter of inferior vena cava by ultrasonography: a new non-invasive method to assess acute changes in vascular filling state.
OBJECTIVE
The aim was to determine whether measurement of the anterior-posterior diameter of the inferior vena cava (IVC) by ultrasonography, before and during deep inspiration, allows indirect information on baseline blood volume and changes in vascular filling state to be obtained in healthy subjects.


METHODS
Blood volume was measured in 12 volunteers by a standard radioactive isotope method. The IVC dimensions were measured by ultrasound in various positions. In addition, in 10 male subjects the effect on the IVC dimensions of volume loading was evaluated by rapid infusion of plasma expander. During and immediately following volume loading, the IVC dimensions and blood volume were remeasured.


RESULTS
Neither the baseline IVC diameters nor any combination of these variables correlated with the concomitant blood volume. Volume loading increased the anterior-posterior IVC dimensions linearly, the largest increase being observed with the maximum IVC diameter and the subject in supine position.


CONCLUSIONS
It follows that ultrasonic IVC indices cannot be used as accurate indirect estimate of baseline blood volume, but provide reliable information on acute changes of the subjects' vascular filling state.
Duvekot
J J
JJ
Academic Hospital Maastricht, The Netherlands.
Cheriex
E C
EC
Tan
W D
WD
Heidendal
G A
GA
Peeters
L L
LL
D000328:Adult; D001810:Blood Volume; D001811:Blood Volume Determination; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D010953:Plasma Volume; D014463:Ultrasonography; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging* / Q000502:physiology