Three-dimensional power Doppler ultrasound of the fetal great vessels.
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Coronary Circulation↗
Biomedical subjects
K D Kalache
Publications and source records attributed to K D Kalache.
Laryngeal atresia, encephalocele, and limb deformities (LEL): a possible new syndrome.
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Abnormalities, Multiple↗
Mild maternal undernutrition in the first half of ovine pregnancy influences placental morphology but not fetal Doppler flow velocity waveforms and fetal heart size.
AIMS: We wanted to investigate whether experimental dietary manipulations during early pregnancy influence placental growth and subsequently the cardiovascular system as assessed non-invasively by ultrasonography in the sheep fetus. METHODS: 21 ewes bearing singletons of uniform age were randomly assigned for the first half of pregnancy to one of the following study groups: fed 100% of their nutritional requirements (i.e. controls), global reduction in total intake by 30% (i.e. 70% global) and reduction in protein intake by 30% (i.e. 70% protein). RESULTS: Placentas from the 70% protein group had significantly more small placentomes, but significantly fewer large placentomes compared to the 70% global group. However, there were no significant differences between the three dietary groups for either the aortic or the umbilical Doppler velocimetry parameters and the fetal heart rate or heart size. CONCLUSIONS: The present study shows that early mild maternal undernutrition produces subtle changes in cotelydonary weight. However, Doppler and echocardiographic parameters were not affected by these changes.
Animals↗
Differentiation between human fetal breathing patterns by investigation of breathing-related tracheal fluid flow velocity using Doppler sonography.
We report our results from the analysis of Doppler measurements of breathing-related fluid flow velocity waveforms in the trachea in human fetuses. Our aim was to determine whether, using the proposed method, reproducible patterns can be recognized over the latter half of gestation. Breathing-related tracheal fluid flow velocity of 47 normal fetuses at 20-39 weeks' gestation were analysed. Colour Doppler was used to document 'streaming' of fluid in the trachea, followed by spectral Doppler to record flow velocity waveforms. More than 40 (median 94; range 42-725) continuous breathing cycles (inspiration+expiration) were obtained in each case. Although breathing-related fetal tracheal fluid flow waveforms were found to be highly variable, we were able to distinguish by visual analysis between a regular and an irregular pattern. Among the regular patterns, we further differentiate between a regular symmetric (sinusoidal type) and a regular asymmetric (deep inspiration with expiratory flow retardation) pattern. The regular pattern occurred consistently in all age groups studied and there were no significant (p<0.05) differences in the occurrence rate of the regular symmetric and asymmetric pattern. The incidence of the regular pattern increased significantly (p<0.05) from 11.74+/-3.38% (mean +/- SEM) at 24-27 weeks to 20.72+/-1.75% at 28-31 weeks of gestation and remained constant thereafter. This study shows that the proposed method can provide detailed information on breathing-related tracheal fluid flow velocity as early as 20 weeks of gestation. The information that a regular symmetric pattern was observed throughout the second half of gestation is important. Hence, a higher standardization of on-going fetal breathing movements studies may be achieved by measuring breathing-related tracheal fluid flow velocity waveform parameters only during this pattern.
Body Fluids↗
Prognostic significance of the pouch sign in fetuses with prenatally diagnosed esophageal atresia.
OBJECTIVE: Esophageal atresia may be diagnosed prenatally by ultrasonographic visualization of the blind-ending esophagus during fetal swallowing, which is referred to as the pouch sign. Our purpose was to determine whether this sign can be used to predict outcomes of affected fetuses. STUDY DESIGN: Four cases of esophageal atresia diagnosed in our center during the past 2 years were analyzed, in conjunction with 3 cases from published series. Ultrasonographic features of the pouch sign were categorized according to localization. RESULTS: In the neck pouch group (n = 3) 1 fetus died in utero and 1 died before a corrective operation could be undertaken. In the only fetus of this group to survive a staged repair was necessary because of a long atretic gap. Conversely, 3 of the 4 fetuses with a mediastinal pouch survived after a successful corrective operation, and primary repair was possible in all cases. CONCLUSIONS: The base of the proximal blind-ending esophagus can be clearly localized by means of ultrasonography. Our data suggest that a neck pouch may be associated with an adverse outcome. This information may be useful in counseling parents when esophageal atresia is diagnosed prenatally.
Esophageal Atresia↗
Ultrasound measurements of the diameter of the fetal trachea, larynx and pharynx throughout gestation applicability to prenatal diagnosis of obstructive anomalies of the upper respiratory-digestive tract.
The purpose of the present study was to obtain normative data for the fetal upper respiratory tract by using high-resolution ultrasound techniques. Furthermore, we wanted to test the potential utility of the resulting normograms in diagnosing obstructive lesions of the trachea and oesophagus. Sonographic measurements of the diameters of the trachea, larynx and pharynx were obtained at well-defined planes from a prospective cross-sectional sample of 198 normal patients of known gestational age between 15 and 40 weeks' gestation. All measurements were performed during fetal apnea and in the absence of swallowing. The same measurements were also obtained from two cases with laryngeal atresia and three cases with oesophageal atresia, all of which were diagnosed prenatally. The data obtained were plotted on the constructed normograms. In normal fetuses approximately linear relationships existed between tracheal, laryngeal and pharyngeal diameter, on the one hand, and gestational age, on the other, with the measurements correlating significantly (p<0.0001) with gestational age. The linear regression coefficients (r2) for the tracheal, laryngeal and pharyngeal diameters were 0.66, 0.55 and 0.32, respectively. The 95 per cent prediction limits were also calculated. In fetuses with laryngeal atresia only the tracheal diameter was significantly higher as compared with that of normal fetuses. Data of the fetuses with oesophageal atresia showed that there were no changes in the upper airway anatomy. Our study provides normative data for the upper respiratory tract. In the prenatal diagnosis of obstructive neck anomalies the usefulness of the data would seem to be limited to those affecting the respiratory tract. Among the structures measured, only the trachea may prove to be of clinical significance.
Cross-Sectional Studies↗
Management of spontaneous congenital chylothorax: oral medium-chain triglycerides versus total parenteral nutrition.
The aim of this article is to compare total parenteral nutrition (TPN) with oral medium-chain triglycerides-diets (MCT) in the management of spontaneous congenital chylothorax. We analyzed retrospectively the charts of 6 patients seen in our tertiary care center and of 11 comparable patients from the literature. All neonates were symptomatic at birth; 15 had bilateral chylothorax. In the neonates who received mainly TPN (n = 9), the chylothorax resolved significantly (p < 0.05) earlier (mean 10 days, SE 1) than in the others, who received mainly MCT (n = 8) (mean 23 days, SE 4). The mean chyle loss was not significantly different between the 2 groups. Our results suggest that TPN is more effective than oral MCT in the treatment of spontaneous congenital chylothorax. These results support the data of Peitersen et al, who reported that most of the positive results with MCT were achieved in postoperative chylothorax of the newborn.
Administration, Oral↗
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 x kP(-1) x kg(-1); sCrs, 0.23 and 1.28 kpa(-1); Rrs, 11.1 and 7.4 kpa x s x L(-1); FRCN2, 14.9 and 10.2 mL x kg(-1); FRCpleth, 28.2 and 25.8 mL x kg(-1); 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 x kPa(-1) x kg(-1); sCrs, 0.43+/-0.08 kpa(-1); Rrs, 5.10+/-0.55 kpa x s x L(-1); FRCN2, 24.0+/-2.5 mL x kg(-1); FRCpleth, 31.1+/-6.0 mL x 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.
Bronchoscopy↗
The upper neck pouch sign: a prenatal sonographic marker for esophageal atresia.
Prenatal suspicion of esophageal atresia is usually based on the finding of a small or absent fetal stomach in association with polyhydramnios. As similar findings may be generated by other abnormalities, confirmation of the diagnosis is generally not possible until birth. We present a case in which the suspicion of esophageal atresia was raised in the 22nd week of pregnancy in the presence of a small stomach bubble associated with a persistent left superior vena cava. The diagnosis was confirmed 4 weeks later by direct visualization of the fluid-filled blind-ending esophagus during fetal swallowing, which we called the upper neck pouch sign. This is the first case in which the onset of this sonographic entity was specifically observed on serially repeated sonograms as early as the 22nd week. The appearance of this direct sign of esophageal atresia is described, and the literature is reviewed.
Adult↗
Doppler assessment of tracheal fluid flow during fetal breathing movements in cases of congenital diaphragmatic hernia.
OBJECTIVE: The purpose of this investigation was to examine the characteristics of breathing-related fluid flow in the trachea of human fetuses with congenital diaphragmatic hernia in the hopes of developing a standard for the prenatal diagnosis of the degree of severity of the resulting pulmonary hypoplasia. Our ultimate goal is the prediction of postnatal mortality in fetuses with congenital diaphragmatic hernia. SUBJECTS AND METHODS: The study comprised six cases of isolated congenital diaphragmatic hernia (one on the right side; five on the left) varying in gestational age from 26 to 36 weeks. Four of the patients survived after surgical repair and two died during the neonatal period owing to lung hypoplasia. Color Doppler was used to visualize the fluid displacement in the trachea generated by fetal breathing movements. Spectral Doppler was then used to analyze the fluid flow velocity waveforms. More than 40 continuous breathing cycles (inspiration + expiration) were recorded for each case. We distinguished between regular and irregular patterns. RESULTS: Only the regular breathing phases, defined as five or more consecutive cycles of symmetric appearance, were considered for analysis. The inspiration and expiration times, the peak velocity of inspired and expired fluid and the volume obtained by integration of the tracheal fluid flow displaced during fetal breathing were compared with those of five healthy fetuses for each gestational age. Only the tracheal volume flow was helpful in predicting outcome. In normal pregnancies this parameter increased from 0.21 +/- 0.10 ml/breath (mean +/- SD) at 26 weeks to 1.37 +/- 0.48 ml/breath at 36 weeks of gestation. A significantly low (p < 0.05) volume flow was found only in the fetuses with congenital diaphragmatic hernia with a lethal postnatal outcome, whereas this parameter was normal in all survivors. CONCLUSIONS: Our preliminary observations suggest that the tracheal volume flow during fetal breathing activity is related to lung growth. In fetuses with severe lung hypoplasia one would expect a significant reduction in this parameter as an expression of deficient fetal lung growth. The displaced fluid volume per breath in the trachea of human fetuses as assessed by Doppler ultrasound may be a useful predictor of outcome in cases of isolated congenital diaphragmatic hernia.
Female↗
Doppler assessment of tracheal and nasal fluid flow during fetal breathing movements: preliminary observations.
Our aim was to determine if it was technically possible to assess fetal tracheal fluid flow during fetal breathing movements, and to compare the data obtained with those recorded in the fetal nasopharynx. Tracheal and nasal fluid flow was analyzed in ten uncomplicated pregnancies, the gestational age ranging between 28 and 38 weeks. Color Doppler was used to detect the fluid displacement in the trachea generated by fetal breathing movements. Spectral Doppler was then used to analyze the fluid flow velocity waveforms. During the same breathing episode, nasal fluid flow was assessed by the same technique. The inspiration and expiration times were variable and not statistically comparable for both nasal and tracheal flow. Peak velocities of inspired and expired fluid were higher in the trachea than in the nose (p < 0.05). We found that the peak velocity of tracheal flow waveforms was significantly higher for inspiration than expiration (p < 0.05). No significant differences were found in the time velocity integral between inspiration and expiration (p = 0.79). The calculated intratracheal flow volume displaced during one breathing cycle increased from 1.3 to 5.0 ml with advancing gestation. Assessment of nasal and tracheal flow, using color and spectral Doppler, is feasible in the human fetus. Intratracheal flow measurements may provide an insight into the effect of fetal breathing movements on lung fluid in the human fetus.
Female↗
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.
Adult↗
Visualisation and measurement of tracheal diameter in the sheep fetus: an ultrasound study with stereomicroscopic correlation.
OBJECTIVE: There is no information on ultrasonographic visualisation of the upper airways in the sheep fetus, but this species permits to examine the accuracy of ultrasonography in measuring the inner tracheal diameter. This was the aim of our study. METHODS: Transabdominal ultrasonography to visualise the trachea was attempted in 16 unsedated Welsh Mountain ewes with a singleton pregnancy at 70 (SD 2) days gestation (term 148 days). The ultrasonographically measured inner tracheal diameter was compared with the actual inner tracheal diameter obtained by stereomicroscopy post-mortem. RESULTS: High-resolution ultrasonography permitted clear imaging of the fetal trachea in 87% (14/16) of the cases analysed. The ultrasound measurements were smaller than the corresponding stereomicroscopic measurements, the mean +/- SD difference between the measurements being 0.40 +/- 0.12 mm. CONCLUSIONS: Improvements in ultrasound have led to increased interest in the assessment of the trachea in human fetuses. Our study in the ovine fetus at mid gestation shows that optimal views of the fetal trachea allowing accurate measurements can be obtained in almost all the cases.
Animals↗
Prenatal diagnosis of right lung agenesis using color Doppler and magnetic resonance imaging.
Unilateral lung agenesis should be suspected in fetuses presenting mediastinal shifting and absence of evidence of diaphragmatic hernia. Confirmation of diagnosis is not possible until birth as other more common lung anomalies may have a similar appearance. We present a case with right lung agenesis diagnosed at 34 weeks of gestation. Important for precise diagnosis was the color Doppler procedure, which revealed the absence of right pulmonary vessels. This is the first case in which unilateral lung agenesis has been recognized prenatally by nonvisualization of the corresponding lung vessels. The prenatally performed magnetic resonance sonography did not offer any advantages over sonography. Postnatally, the diagnosis was confirmed, and sinus venosus defect was also found. To prevent recurrent cardiopulmonary crisis, which could be caused by mediastinal shift, a tissue expander was implanted successfully at 3 months of age.
Adult↗