Elaine E. Farrell

Amniotic fluid lamellar body count: a rapid and reliable fetal lung maturity test

Objective To evaluate the lamellar body count as a predictor of fetal lung maturity. Methods We conducted a prospective clinical outcome study. Amniocentesis was performed for evaluation of fetal lung maturity status within 72 hours of delivery in 130 patients. A lamellar body count was performed on each specimen, and a lecithin-sphingomyelin ratio and lung phospholipid profile were performed when possible (insufficient sample or contamination in eight cases). Each infant was evaluated for evidence of respiratory distress syndrome (RDS). Results A lamellar body count exceeding 30,000/μL predicted pulmonary maturity correctly in all cases (negative predictive value 1.00). All 16 cases of RDS had counts of 30,000/μL or less. If the lamellar body count was less than 10,000/μL, the positive predictive value for RDS was 67%, and the likelihood of a mature result from chromatographic phospholipid analysis was low (one of 14, 7%). Values between 10,000–30,000/μL indicated intermediate risk (four of 39, 10%) for developing RDS. Phospholipid analysis indicated fetal lung maturity in 35 of 39 (90%) cases with lamellar body counts in the intermediate risk range. Conclusions The lamellar body count compares favorably with traditional phospholipid testing in the prediction of fetal lung maturity. Phospholipid analysis is not needed with lamellar body counts greater than 30,000/μL or less than 10,000/μL, but may be of benefit for values in the intermediate risk range. Advantages of this test include speed, objectivity, small sample volume required, and universal availability of instrumentation.

Factitious hyperinsulinemic hypoglycemia in infancy: diagnostic pitfalls.

The patient is an AfricanAmerican male born at 40 weeks gestation to a 19-year-old gravida 2 para 2 mother whose pregnancy and delivery were uncomplicated. The infant was large for gestational age (3,934 grams), and the first routine glucose measured by reagent strip was 1.7 mmol/L (30 mg/dL). The infant was asymptomatic. Early enteral feedings were introduced without recurrence of hypoglycemia, and he was discharged at 24 hours of age. At 2 months of age he was admitted to a local hospital with the diagnosis of pneumonia. After 2 days of receiving dextrose-containing solution and antibiotics, he was doing well and was to be discharged; however, he was found in bed drooling, staring, and poorly responsive and was transferred to the Neonatal Intensive Care Unit of a tertiary care center where his serum glucose

Nesidioblastosis is Not a Histopathologic Diagnosis. 380

Nesidioblastosis is a condition characterized clinically by intractable hyperinsulinemic hypoglycemia. Since serum insulin levels are rarely extremely elevated, diagnostic confirmation has historically relied upon characteristic histopathologic changes in the pancreatic tissue removed as a therapeutic modality of this condition. Although the finding of abundant nests of endocrine tissue budding off of ductal elements is considered to be confirmatory, there have been reports in the adult and pathology literature that such findings may be present in normal individuals. We present here the case of an infant which demonstrates that nesidioblastosis is not a histopathologic diagnosis.

HYPERNATREMIA IS ASSOCIATED WITH SEVERE INTRAVENTRICULAR HEMORRHAGE IN EXTREMELY LOW BIRTHWEIGHT INFANTS. 1182

Intraventricular hemorrhage (IVH) is an incompletely understood complication of extremely low birthweight (ELBW) premature infants without specific treatment or preventive strategies. Although early studies suggested that serum sodium (Na) and/or sodium bicarbonate may be associated with IVH, a more recent report found no correlation. We hypothesized that early hypernatremia was present in ELBW infants with severe IVH and performed a case-control study to investigate this hypothesis. ELBW infants with severe IVH (bilaterally grade III or grade IV) treated at Evanston Hospital between 1990-1995 were compared to gestational age and birthweight matched ELBW infants with a normal cranial ultrasound over the same time period. Charts of 14 IVH patients and 14 case-controls were reviewed and data recorded including birthweight, gestational age, serum sodium maximum on day of life #1, 2, and 3, fluid intake, minimum blood pressure, minimun arterial pH, and specifics of cranial ultrasound examinations. Groups were similar in gestational age (25.3± 0.3 wks control vs 24.7 ± 0.3 wks IVH, p=NS) and birthweight(824 ±28 gm control vs 730 ± 58 gm IVH, p=NS). All IVH patients had grade IV bleeds except 4 with bilateral grade III IVH. We found that maximum serum sodium values were higher in the IVH group compared to controls at each day studied (day 1: 152 ± 3.6 meq/L IVH vs 142 ± 1.4 control, p < 0.02; day 2: 160 ± 5.0 meq/L IVH vs 149 ± 1.5 control, p < 0.03; day 3: 157 ± 1.9 meq/L IVH vs 150 ± 1.5 control, p < 0.02). Furthermore, the IVH group had a significantly higher percentage of babies with sodium values ≥ 155 meq/L compared to controls on the first days of life (day 1: 50% IVH vs 0 controls; day 2: 55% IVH vs 8% control). In addition, the IVH group had more acidosis on the first day of life (minimum pH 7.15 ±.06) compared to controls (pH 7.30 ±.02, p < 0.02), but similar acid-base balance on the second and subsequent days of life. We conclude that hypernatremia on the first few days of life is associated with severe IVH in ELBW infants. Further studies are warranted to delineate whether early hypernatremia may predispose ELBW infants to the occurrence of a significant intraventricular hemorrhage.

1406 INTRAVENOUS NITROGLYCERIN (NTG) IN THE TREATMENT OF PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN (PPHN)

We report the use of intravenous NTG in a 2600 gram, 37-week gestational age newborn with PPHN unresponsive to hyperventilation(HV). The diagnosis of PPHN was made based on unexplained hypoxemia, initial positive response to HV, and evidence of a ductal level right-to-left shunt. After repeated transient responses to HV and pancuronium therapy, the PaO2/FiO2 dropped to 53. An IV continuous infusion of NTG was begun at 5.9 mcg/kg/ min. at 45 hours of age. The infusion was increased in a step-wise manner to 13 mcg/kg/min. After each increase, a transient elevation in PaO2/FiO2 occurred. After the increase to 13 mcg/kg/min., and without any alteration in ventilatory settings, a sustained rise in PaO2/FiO2 to 242 was noted. No significant changes in CVP (5-6 cm H2O) or arterial blood pressure(mean= 54-59 mm Hg) pre- or post-NTG were seen. NTG was stopped by Day 4, pancuronium and HV by Day 5, and assisted ventilation by Day 9. He was discharged home on Day 19. Twelve month follow-up is normal.Intravenous nitroglycerin may be as effective a pulmonary vasodilator in the treatment of neonates with PPHN and may be used with significantly less side effects than seen with tolazoline. Further clinical trials will be necessary to establish its efficacy.