RENAL DOPPLER ULTRASOUND IN CHILDREN WITH NORMAL UPPER URINARY TRACTS- EFFECT OF FASTING, HYDRATION WITH NORMAL SALINE, AND FUROSEMIDE ADMINISTRATION

Objectives. To study the age dependency of renal resistive index (RI) and to study the effect on the renal RI of fasting, intravenous infusi on of normal saline, and administration of furosemide in children with normal upper urinary tracts. Methods. The study included 28 nonobstru cted renal units in 15 boys ranging in age from 5 to 11 years. Diureti c renography and Doppler ultrasonography were attempted in all childre n. Doppler ultrasonography was carried out under three different condi tions: fasting state, 30 to 60 minutes after intravenous infusion of n ormal saline (15 mL/kg), and 10 minutes after administration of furose mide (1 mg/kg; maximum, 40 mg). Results. There was an inverse correlat ion between age and RI of both renal units under the three conditions of Doppler studies. At fasting state mean RI was 0.70 +/- 0.04, wherea s 15 of 28 renal units (54%) had an RI of 0.70 or higher. Intravenous infusion of normal saline significantly decreased the RI to 0.63 +/- 0 .04 (P < 0.000001). Injection of furosemide caused a further significa nt decrease of RI from 0.65 +/- 0.04 to 0.60 +/- 0.04 (P < 0.002). Con clusions. The renal RI in healthy children is age dependent. in the fa sting state, 54% of nonobstructed renal units in children have an RI o f 0.70 or higher. Intravenous infusion of normal saline and administra tion of furosemide can independently cause a significant decrease of t he RI in nonobstructed renal units in children.