RENAL BLOOD-FLOW VELOCITY IN PRETERM AND TERM NEONATES DURING THE 4THDAY OF LIFE - CHANGES IN RELATION TO GESTATIONAL-AGE AND BIRTH-WEIGHT

Measurements of renal artery blood flow velocity have been previously reported during prenatal life and during the first month of life in ne onates. Since renal flow velocity increases during the first 3 days of postnatal age we determined, during the fourth day of life, the chang es of renal blood flow velocity in relation to gestational age and bir th weight in 109 healthy preterm and term infants with gestational age between 26 and 42 weeks and birth weight between 750 and 3,730 g. Ren al arteries were insonated about 3 mm from the abdominal aorta, by pla cement of a microconvex 7-MHz transducer below the costal margin in th e dorsolateral area of the right or left flank. Mean flow velocity sig nificantly increased with advancing of gestational age and birth weigh t. This study provides normative data for renal artery blood flow velo city in healthy preterm and term infants during the fourth day of life .