We report on five preterm infants (34 to 36 weeks' gestation) in whom an overwhelming illness developed within the first 48 hours of life. Each had mild respiratory distress that progressed within 48 hours to deep coma requiring ventilatory assistance. Ammonia concentrations in the plasma ranged from 844 to 7640 microgram per deciliter. Four received exchange transfusion and peritoneal dialysis; ammonia values returned to the normal range (less than 150 mug per deciliter) within 72 hours and remained there even after protein challenge. These four subsequently fed and developed normally. The fifth infant died without an attempt to lower plasma ammonia. In this infant (and two of the others) urea-cycle enzymes measured in liver tissue were in the normal range. Transient hyperammonemia of unknown cause may be a relatively common variety of neonatal hyperammonemia; it responds well to prompt diagnosis and aggressive therapy.

Fifty-three low birth weight high risk newborns who developed progressive hydrocephalus despite a trial period of intermittent lumbar punctures underwent cribside ventriculoperitoneal shunt placement. They all weighed less than 2000 g at the time of shunting (mean, 1308.6 g +/- 398.2 SD). The operative procedures were performed at a mean age of 31.5 days +/- 16.1 (SD). There were no deaths in this series. During the nursery stay, 14 patients required operative revisions for obstruction. The most common problem was infection, which occurred in 13 (24.5%) after the primary intervention and in another 5 of the 14 (35.7%) patients who required revision. The overall infection rate/patient was 26.9%. Shunt removal and intensive antibiotic therapy cured the infection in all but 1 patient. Premature, low birth weight newborns may undergo ventriculoperitoneal shunting, but close follow-up for complications such as infection and shunt obstruction is always required.

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ABSTRACT. The concentration of plasma atrial natriuretic factor (ANF) and the mechanism for its secretion were investigated in 17 preterm infants with respiratory distress. Their mean gestational age was 29 wk and wt 1250 g. The infants were followed during the first week of life by sequential Doppler ultrasound studies. Ductal openness versus closure and amount of ductal flow were correlated with plasma ANF concentrations. In a subset of 10 infants, sequential Doppler color flow mapping was used to quantify the ductal flow. During the first 72 h, plasma ANF was high, 361 pg/mL; it decreased to 96 pg/mL by the end of the 1st wk. (4, 5). In neonates with RDS (6) plasma concentration of ANF is increased compared to normal newborns. In these patients the peak plasma ANF concentration coincides with the diuretic phase found between 18 to 43 h of age (7).To clarify the association of ANF secretion and hemodynamic changes in preterm infants with RDS, we determined the Qp/Qs ratio and ductal closure by CFM with a method we developed previously (8). The focus of this study was the effect of ductal flow on plasma ANF concentration in preterm infants with RDS. MATERIALS AND METHODSSeventeen preterm infants (26-33 wk gestation) with birth wt of 0.66 to 1.95 kg (mean 1.25 kg) developed clinical signs and radiographic features consistent with RDS. Nine infants were delivered by caesarean section, and Apgar scores ranged from 3 to 8 at 1 min (mean 6) and from 6 to 9 at 5 min (mean 8). In 15 infants, analysis of amniotic fluid obtained within 24 h before birth revealed lecithin/sphingomyelin ratios less than 2.0 with absence of phosphatidylglycerol, and in two remaining infants tracheal aspirates obtained at birth contained no phosphatidylglycerol. These findings and the clinical course were consistent with severe RDS. This was further substantiated by calculating the arteriolar/alveolar oxygen tension ratio (9) at 6 h of age (0.17 5 0.08: mean + SD), which confirmed the disturbance in gas ANF, atrial natriuretic factor exchange and the requirement for supplemental oxygen and CFM, color flow mapping mechanical ventilation. Infants included in this study had no LA/Ao ratio, left atrial to aortic root diameter evidence of chorioamnionitis, congenital infection, or major PDA, patent ductus arteriosus malformations.Qp/Qs, pulmonic to systemic blood flow ratio Blood samples of 0.5 mL were drawn through umbilical artery catheters into ice-cold EDTA-containing tubes that were rapidly RDS, respiratory distress syndrome centrifuged at 300 x n. Plasma was sevarated for immediate freezingand stored at -3 0 "~ for up to 3 mo before ANF analysis. From each patient during the 1st wk of life, one to four samples were taken within 3 h of a CFM study. RIA was camed out as ANF is a secreted from the atria of the heart (1). In term previously described (10). Sensitivity of the method is 5 pg/mL. newborns plasma concentration of ANF is increased during the The intra-and interassay coefficients of variation are 10.6 and first 2 to 4 d of life (2,...

The experience of the Special Care Nursery of the University of California Medical Center, San Diego, in the management of the high risk newborn with progressive ventricular enlargement is reviewed, and the physiopathological basis of progressive ventricular enlargement is analyzed.