Comparison of sonographic inferior vena cava and aorta indexes during fluid administered in children

This prospective, observational study evaluated changes in ultrasound measurements of the inferior vena caval index (IVCI), the aorta diameter/IVC diameter index (Ao/IVCD), and the aorta area/IVC area index (Ao/IVCA) during fluid administration in children requiring intravenous fluid administration.

Children who presented to the pediatric emergency department with symptoms of dehydration were enrolled between May 2015 and February 2016. The maximum diameter of the aorta, from inner wall to inner wall, and the long and short axis diameters of IVC were measured using a convex array transducer in the transverse view. Subsequently, we measured the diameter of the IVC at the subxiphoid area during inspiration and expiration in longitudinal view. We calculated IVCI, Ao/IVCD, and Ao/IVCA during administration of 10ml/kg and 20ml/kg normal saline boluses.

IVCI and Ao/IVCA significantly changed immediately after administration of initial 10ml/kg of NS. Ao/IVCA showed significant change during the additional administration of 10ml/kg (total 20ml/kg) normal saline boluses (1.43, IQR 1.12-1.86 vs. 1.08, IQR 0.87-1.45, p value<0.001). No significant changes were observed for IVCI and Ao/IVCD. Ao/IVCA was significantly correlated with the volume of fluid administered. The coefficient between initial and administration of the 10ml/kg normal saline bolus was -0.396 (p value=0.010), and that between the 10ml/kg and 20ml/kg normal saline boluses was -0.316 (p value=0.038).

Ao/IVCA showed better correlations with the volume of fluid administered than IVCI and Ao/IVCA. Ao/IVCA might be a promising index for assessing the effects of fluid administration.