No abstract

SummaryThe lungs of intrauterine 135-136-day-old lambs were lavaged with amnionic fluid, with or without meconium, to determine the effect on lung phosphatidylcholine (PC) concentration, synthesis, and function. No differences were apparent between animals lavaged with amnionic fluid or amnionicfluid with meconium. When lavaged lungs were compared to nonlavaged controls, no detectable differences were observed in histology or the quantity of saturated (SPC) and unsaturated phosphatidylcholine (UPC). However, the lavaged lungs retained a larger fraction of maximal lung volume at 5 cm H z 0 distending pressure and the incorporation of (32P) orthophosphate into lung PC was significantly reduced. In addition, two lavaged animals who became acidotic (pH < 7.20) exhibited decreased incorporation of (14C) palmitate into whole lung unsaturated, and saturated phosphatidylcholine. SpeculationThese data indicate that amnionic fluid can reduce lamb lung de novo synthesis of PC and may contribute to the alterations in lung PC found in neonatal syndromes of respiratory distress. Acidosis may accentuate this effect.The fetal development of the mammalian alveolus is characterized by the transition of columnar epithelium to attenuated differentiated alveolar epithelium surrounding the fluid filled potential airspace (8,25,35).The fluid in the fetal lung, the tracheal-bronchial fluid (TBF), is comparable in volume to the functional residual volume measured after the onset of air-breathing (21). TBF flows out of the trachea at a near constant rate under uniform intrauterine conditions and is biochemically unique and distinguishable from other fetal fluids (1,2,4,15,33). The rate of TBF production and the short duration of fetal respiratory activity limit the volume of TBF and amnionic fluid (AF) exchange to less than 1 ml per ventilation under normal intrauterine conditions (12,28,29,36).Under asphyxia1 conditions the duration, intensity, and volume of fluid ventilation increase such that an estimated 50 ventilations will exchange approximately 0.90 of the TBF (12, 21) with AF. MATERIALS AND METHODS ANIMALSYearling ewes with dated pregnancies x-rayed to confirm the pregnancy were assessed as to hemoglobin concentration, white blood count, and intestinal parasites. Healthy animals were fed horse checkers (Purina Ralston Company, St. Louis, Missouri) and ad libitum alfalfa hay and water up to 24 hr before surgery.The ewes at 135-136 days of gestation were anesthetized with a rapid infusion of ketamine (Vetelar, Parke Davis and Company, Detroit, Michigan), approximately 7 mg/kg, and maintained with an infusion of 1 mg/ml in 0.10 dextrose and 0.25 N saline at a rate of 3-5 ml/kg/min. A laparotomy was performed in the supine position and a hysterotomy executed over the fetal neck. The fetal neck was marsupialized to the uterine wall, the fetal trachea dissected free, ligated proximally, and cannulated 1-2 cm with snug fitting and bevelled tygon tubing which was secured with silk ties. The skin was closed and control animals received no...

A retrospective review of the types of patients seen and the accuracy of the diagnosis made was undertaken for patients referred for comprehensive ultrasound examination in a large private perinatal practice. A review of the perinatal ultrasound database, neonatal intensive care database, and hospital charts was done in 1338 patients referred to the perinatal ultrasound laboratory for comprehensive ultrasound examination during a 2-year period. Accuracy of the ultrasound diagnosis and relationships between structural anomalies seen on ultrasound examination and perinatal outcome was undertaken. Positive and negative predictive values for the ultrasonic diagnosis were 82% and 98%, respectively. There were 19 (1.4%) false-positive diagnoses and 38 (2.8%) false-negative diagnoses. There was a high correlation between structural anomalies and chromosomal anomalies, with 15 of the 87 infants (17.2%) with structural anomalies also having chromosomal anomalies. The accuracy of ultrasonic diagnosis for comprehensive examinations in a large private perinatal practice compared favorably with previous reports in the literature. The information presented in this study should be helpful to obstetric centers with similar patient populations.