Ultrasound measurements of the diameter of the fetal trachea, larynx and pharynx throughout gestation and applicability to prenatal diagnosis of obstructive anomalies of the upper respiratory-digestive tract

Abstract

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. Copyright © 1999 John Wiley & Sons, Ltd.

Widespread and efficient marker gene expression in the airway epithelia of fetal sheep after minimally invasive tracheal application of recombinant adenovirus in utero

“…4 To overcome these problems, other investigators have used complicated open uterus surgery, 5,7,10 or at least laparotomy and fetoscopy, 11 both of which are highly invasive techniques, but the results of gene transfer to the airways were still very poor. Because the upper respiratory tract is easily visualized by ultrasound in the sheep 12 and human fetus, 13 we chose in this study to use percutaneous ultrasoundguided injection to access the fetal trachea directly in utero.…”

The morphometric development of the fetal larynx during the fetal period

“…In fetuses, the inadequate literatures regarding this subject were presented [8,[10][11][12]. The obtained data from fetus studies did not detail in contrast to the adult studies.…”

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

“…The approach, which we have previously termed pulmonary Doppler ultrasonography 13 is a major advance over other modalities to assess fetal breathing movements for the following reasons. First, it is sensitive enough to allow a differentiation between distinct fetal breathing patterns as early as the second trimester 14 .…”

“…In human pregnancies, this phase of lung development (20 -35 weeks of gestation) is characterised by an important increase of lung growth 29 , tracheal growth 13,30 , lung compliance 31 as well as lung liquid volume and secretion rate 23 . Which of these factors mainly influence fetal breathing movements related to upper airways dynamic during this stage of lung development remains speculative.…”