Intraventricular haemorrhage and the renin-angiotensin-aldosterone system in very low birthweight infants.
Blood volume, plasma renin activity (PRA) and urine aldosterone excretion (UAE) were measured in ten very low birthweight infants who had a Grade 3 or 4 intraventricular haemorrhage (IVH) during the first 2 days after birth. Mean (range) birthweight was 950 (630-1500) g and gestational age was 27 (23-31) weeks. Nine infants were receiving assisted ventilation and one was breathing spontaneously. Eight IVH occurred on the first postnatal day and two on the second; seven were symptomatic and three asymptomatic. PRA was significantly higher than control values on Day 1 only; median 244 (range 91-654) ng/ml per h vs. 64 (4-259) ng/ml per h (P less than 0.01). Infants with symptomatic IVH in the preceding 8 h (n = 6) all had PRA greater than 300 ng/ml per h; none of these infants had received transfusions or volume expansion between IVH and PRA measurement. PRA was less than 100 ng/ml per h in the three infants with asymptomatic IVH and one infant with greater than 24 h interval between IVH and PRA measurement; three of these four had received transfusions prior to PRA measurement. UAE was not significantly different from control values on either Day 1 or Day 2. Blood volume at 22 +/- 3 h postnatal age ranged from 75 to 107 ml/kg. There was an inverse logarithmic correlation between PRA and blood volume (r = 0.883; P less than 0.005), with PRA values exceeding 300 ng/ml per h when blood volume was less than 90 ml/kg. UAE did not correlate with either PRA or blood volume.(ABSTRACT TRUNCATED AT 250 WORDS)
Leslie
G I
GI
Department of Pediatrics, University of Alabama, Birmingham.
Philips
J B
JB
Cassady
G
G
D000450:Aldosterone / Q000652:urine; D001810:Blood Volume / Q000502:physiology; D002543:Cerebral Hemorrhage / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002552:Cerebral Ventricles; D006801:Humans; D007230:Infant, Low Birth Weight / Q000378:metabolism* / Q000502:physiology; D007231:Infant, Newborn; D012084:Renin-Angiotensin System / Q000502:physiology*
D000450:Aldosterone