Karim D. Kalache

Outcome of 60 neonates who had ARED flow prenatally compared with a matched control group of appropriate‐for‐gestational age preterm neonates

To describe the course and outcome of fetuses with absent or reversed end‐diastolic (ARED) flow in the umbilical artery (UA) and to examine the influence of prematurity according to gestational age at delivery.

PRENATAL DIAGNOSIS OF LARYNGEAL ATRESIA IN TWO CASES OF CONGENITAL HIGH AIRWAY OBSTRUCTION SYNDROME (CHAOS)

Complete occlusion of the upper airways is known to cause secondary morphological changes, including bilaterally enlarged hyperechogenic lungs, dilated trachea, and hydrops. Prenatal diagnosis of upper airway obstruction has been described in several cases. In these reports, the diagnosis was primarily attributed to indirect signs, and the authors were in doubt as to whether the location of the obstructed area (larynx, glottis or trachea) could be precisely visualized by ultrasound. In this paper two cases are reported presenting the features of congenital high airway obstruction syndrome (CHAOS) diagnosed at the 22nd week of gestation. In both cases, the upper neck was perfectly visualized in a coronal plane. At the onset of fetal breathing movements, the stenotic larynx remained in a closed position. By positioning a colour signal on the fluid‐filled dilated trachea, we noticed absence of flow throughout the onset of breathing activity. We conclude that the atretic area must be situated at the level of the larynx. Because of the poor prognosis of laryngeal stenosis and the presence of associated anomalies, both pregnancies were terminated in the 23rd week. This report shows that the application of colour and spectral Doppler may be helpful in the differential diagnosis of fetuses with CHAOS.

Right-sided pulmonary aplasia: longitudinal lung function studies in two cases and comparison to results from term healthy neonates.

Agenesis of the right lung was diagnosed prenatally in two neonates born at 36 and 37 weeks, respectively. Computed tomographic scans and magnetic resonance imaging indicated that both cases had a Type 2 pulmonary agenesis, which was confirmed later by bronchoscopy. Both patients were clinically stable during the neonatal period. Serial pulmonary function tests revealed a decrease in specific respiratory system compliance (sCrs) in both neonates and a marked discrepancy between functional residual capacity measured by the nitrogen washout technique (FRCN2) and by plethysmography (FRCpleth) on follow‐up. Early decrease of respiratory system compliance (Crs) and increase of respiratory system resistance (Rrs) in one infant preceded the onset of tracheal stenosis, which remained asymptomatic until the age of 8 weeks, when the infant developed acute respiratory failure requiring intubation and mechanical ventilation with high airway pressures. Aortopexy, implantation of a tissue expander into the right hemithorax, and laser ablation of fibrotic tissue at the site of tracheal stenosis were performed to achieve successful extubation. The second infant remained asymptomatic. Values for lung mechanics and volumes for both infants with pulmonary aplasia were as follows: Crs, 3.43 and 10.60 mL · kPa−1 · kg−1; sCrs, 0.23 and 1.28 kpa−1; Rrs, 11.1 and 7.4 kpa · s · L−1; FRCN2, 14.9 and 10.2 mL · kg−1; FRCpleth, 28.2 and 25.8 mL · kg−; FRCN2: FRCpleth ratio, 0.56 and 0.54 for patients 1 and 2, respectively. These values differed considerably from results of a control group of nine term healthy neonates (Crs, 10.0 ± 1.8 mL · kPa−1 · kg−1; sCrs, 0.43 ± 0.08 kpa−1; Rrs, 5.10 ± 0.55 kpa · s · L−1; FRCN2, 24.0 ± 2.5 mL · kg−1; FRCpleth, 31.1 ± 6.0 mL · kg−1; FRCN2:FRCpleth ratio, 0.78 ± 0.10). In conclusion, serial assessment of lung mechanics and pulmonary gas volumes detects airway obstruction early in neonates with unilateral lung agenesis. Bronchoscopy is recommended. Along with conventional surgical procedures, an expandable implant may improve management or prevent respiratory failure in selected cases. Pediatr Pulmonol. 1998; 26:138–144.

Does fetal tracheal fluid flow during fetal breathing movements change before the onset of labour

Objective To examine changes in intra‐tracheal fluid flow parameters during fetal breathing movements throughout the second half of pregnancy in the normally developing human fetus.