Objective: The evaluation of individual parameters of renal circulation in hypotrophic newborns by means of Doppler sonography. Patients and methods: Doppler evaluation of circulation of a. renalis (AR) and in intraparenchymal arteries (IP) of the right and left kidney in 50 hypotrophic newborns (20 boys, 30 girls). Results: All observed rate parameters displayed higher values in AR than in IP. The resistance index (RI) calculated from parameters in AR was higher (0.77 ± 0.08) than in IP (0.58 ± 0.08) (p<0.0001). Similar differences were also observed in the pulsatility index (PI) (1.69 ± 0.53 vs. 0.91 ± 0.24) (p<0.0001). The side comparison of values of the RI and PI indices did not show significant intraindividual differences between the right and left kidney (p>0.05). Conclusion: Results of the study indicate demonstrable differences in the values of the observed parameters in a. renalis centralis vs. intraparenchymal arteries of hypotrophic newborns. At the same time the authors determined standard values of the resistance index and pulsatility index of renal circulation in the hypotrophic newborns.

        Key words: newborn, Doppler sonography, kidneys, resistance index