Fetal breathing-related nasal fluid flow velocity in uncomplicated pregnancies

The human newborn's umwelt: Unexplored pathways and perspectives

Historically, newborns, and especially premature newborns, were thought to "feel nothing." However, over the past decades, a growing body of evidence has shown that newborns are aware of their environment, but the extent and the onset of some sensory capacities remain largely unknown. The goal of this review is to update our current knowledge concerning newborns' perceptual world and how ready they are to cope with an entirely different sensory environment following birth. We aim to establish not only how and when each sensory ability arises during the pre-/postbirth period but also discuss how senses are studied. We conclude that although many studies converge to show that newborns are clearly sentient beings, much is still unknown. Further, we identify a series of internal and external factors that could explain discrepancies between studies, and we propose perspectives for future studies. Finally, through examples from animal studies, we illustrate the importance of this detailed knowledge to pursue the enhancement of newborns' daily living conditions. Indeed, this is a prerequisite for assessing the effects of the physical environment and routine procedures on newborns' welfare.

Prenatal assessment of pulmonary maturity on 3-D ultrasound

AIM

The aim of this study was to assess the feasibility and accuracy of 3-D ultrasound indices to evaluate fetal lung maturity, and to establish a normal reference for fetal lung volume (FLV) and fetal lung-to-liver intensity ratio (FLLIR) in a Chinese population.

METHODS

A total of 1022 pregnant women with singleton pregnancy were prospectively studied between June 2008 to June 2011. Ultrasound examination was performed. The breathing-related nasal fluid flow (BRNFF) spectrum, FLV, pulmonary artery blood flow parameters, and echo intensity of the lung were calculated. Phosphoglycerides in the amniotic fluid were measured on thin layer chromatography.

RESULTS

FLLIR and FLV were positively and linearly correlated with gestational age (F = 0.915, 0.846). Indicators of fetal lung maturity included FLLIR >1.1, FLV >50 mL, and regular BRNFF spectrum, with positive likelihood ratios of 12.28, 11.78, and 11.63, independently.

CONCLUSION

Ultrasound indices, including FLLIR, FLV and BRNFF may serve as useful alternatives to amniotic fluid phospholipids in analyzing fetal lung maturity in Chinese patients.

Long-term failure of alveologenesis after an early short-term exposure to a PDGF-receptor antagonist

Survivors of moderate-to-severe bronchopulmonary dysplasia have impaired alveologenesis lasting at least into early adult life. The mechanisms underlying this long-term effect are unknown. We hypothesized that short-term inhibition of growth factor-mediated early alveolar formation would result in a long-term impairment of subsequent alveologenesis. Neonatal rats were injected daily with the platelet-derived growth factor (PDGF) receptor antagonist, imatinib mesylate, from day 1-7 of life, to inhibit the early alveolar formation occurring by in-growth of secondary crests into precursor saccules. The pups were then allowed to recover for 7, 14, 21, or 58 days. In imatinib-treated pups, DNA synthesis in total lung cells, and specifically in cells of secondary crests, was reduced at day 8 of life, had rebounded on day 14 of life but was then again reduced by day 28 of life. At day 8 of life, imatinib-treated pups had impaired alveologenesis as reflected by a decrease in secondary crests, an increase in alveolar size, and an overall decrease in both estimated alveolar number and generations compared with age-matched controls. No meaningful recovery was observed, even after a 21- or 58-day recovery period. The lungs of imatinib-treated pups had increased fibulin-5 content and an abnormal deposition of elastin. We conclude that reduced signaling through the PDGF pathways, at an early stage of alveologenesis, can result in long-lasting changes in lung architecture. A likely mechanism is through impaired formation of the elastin scaffold required for alveolarization.

Photogrammetry of fetal breathing movements during the third trimester of pregnancy: observations in normal and abnormal pregnancies

OBJECTIVE

To evaluate parameters of fetal breathing movements-displacement of the fetal abdominal wall during inspiration and expiration, time of inspiration and expiration and speed of inspiration and expiration-between 30 and 36 weeks' gestation in normal pregnancies, and in those complicated by gestational diabetes or maternal hypertension.

METHODS

Three categories of pregnancy were investigated: 49 were normal, 16 had pregnancy-induced diabetes and 10 were hypertensive. According to their gestational age, the patients were divided into two groups: Group A between 30 and 32 weeks' gestation and Group B between 33 and 36 weeks. Using photogrammetry and a computer-operated algorithm, six parameters of fetal breathing movements were investigated.

RESULTS

There were significant differences in the various fetal parameters measured among the three categories of pregnant women. Up until 32 weeks of gestation, the displacements during inspiration and expiration were larger, the speeds of inspiration and expiration were higher, and the times for inspiration and expiration were shorter in the diabetic and hypertensive groups than in the normal group. In the later period, between 33 and 36 weeks, fetuses of pregnancy-induced diabetic patients showed the lowest inspiration and expiration times and the highest speeds of inspiration and expiration.

CONCLUSIONS

Photogrammetry in conjunction with a computer-operated algorithm can be used to assess fetal breathing movements. There are significant differences in fetal breathing movements between normal pregnancies and those that are complicated by gestational diabetes or hypertension.

Assessment of fetal swallowing with gray-scale and color Doppler sonography

OBJECTIVE

Our study was focused on the evaluation of fluid dynamics to assess the value of gray-scale and color Doppler sonography for evaluating the development of fetal swallow-related movements from early gestation until birth.

MATERIALS AND METHODS

We examined 56 fetuses from weeks 15-39 of gestation. Each fetus was examined throughout four distinct periods of gestation: weeks 15-18, 22-25, 30-34, and 37-39. During the examination, seven gray-scale sonography or color Doppler sonography patterns and their prevalence were considered.

RESULTS

Mandibular and/or labial movements (chi2 = 56.4, p < 0.0001) and their rhythmic activity (chi2 = 41.4, p < 0.0001) were seen on gray-scale sonography in an increasing percentage of fetuses as gestational age increased. Doppler findings showed an increase for nose-mouth flow signals (chi2 = 57.6, p < 0.0001), larynx-esophagus flow signals (chi2 = 13.2, p = 0.0003), and effective swallowing (chi2 = 36.0, p < 0.0001) as gestational age increased.

CONCLUSION

There is a trend in the fetus toward development of increased coordinated movement and more functional nose-mouth flow with increasing gestational age: 32.1% of the 56 fetuses in our series achieved effective swallowing at 37-39 weeks, on the basis of gray-scale and Doppler evaluations. Knowledge of the physiologic mechanism involving swallowing development may allow identification of altered swallow-related movements in fetuses with malformations of the digestive tract or with neurologic disorders.

Analysis of fetal breathing movements at 30-38 weeks of gestation

AIMS

This study reports the changes in patterns of fetal breathing movements recorded with a photogrammetric method in three successive periods of gestation.

METHODS

Respiratory movements were studied in fetuses of 28 healthy women with uncomplicated pregnancies of 30-38 weeks of gestation. Women were divided into three groups according to gestational age of the fetus: 30-32 weeks, 7 fetuses; 33-36 weeks, 9 fetuses; and 37-38 weeks, 12 fetuses. Sonographic images of the fetuses were recorded on videotape, digitized (1 image per 0.12 s) and analyzed with specially developed software.

RESULTS

The proportion of fetuses in each age group for which movements were detectable was similar in all three groups, as was the frequency of movements. Duration of a complete respiratory cycle, the inspiratory phase and the expiratory phase tended to be shorter at 33-36 weeks of gestation than in younger and older fetuses. Fetuses in the 30-32-week group had slower breathing rates than fetuses in the two older groups.

CONCLUSIONS

The photogrammetric technique revealed differences in some patterns of fetal breathing movements between weeks 30-32, 33-36 and 37-38 of gestation. The data provide a sound basis for relating changes in fetal breathing movements with physiological and anatomical changes that occur as the respiratory system matures.

Olfaction in the fetal and premature infant: functional status and clinical implications

This article considers olfaction as a functioning source of information for the fetus and the neonate, born on term or prematurely. It aims to present how odors are involved in the sensory continuity between the prenatal and postnatal environments and how they influence the earliest adaptive responses of newborns in the realms of self-regulation, emotional balance, feeding, and social interactions.Finally, it evaluates odors as sensory means to ameliorate the physiologic and behavioral responses of preterm infants to the adverse impacts of separation from mother, nonoral feeding, or iatrogenic distress.

Ultrasonographic patterns of fetal breathing movements in normal pregnancy

OBJECTIVE

To assess through pregnancy fetal breathing movements (FBMs) patterns detected by M-mode and Doppler velocimetry technology.

METHODS

In this cross-sectional study FBMs were investigated in 1882 uncomplicated pregnancies over a 4-year period. Abdominal and thoracic wall movements of fetuses between 14 and 40 weeks of gestation were studied by M-Mode scan, and color Doppler velocimetry with spectral imaging analysis was used to investigate the presence of FBMs associated with nasal fluid flow velocity waveforms (NFFVWs).

RESULTS

Abdominal movements were observed in 19% of cases when gestation was less than 20 weeks and in 61% of cases when it was between 21 and 25 weeks; chest movements were significant after 21 weeks; and NFFVWs were detected at 22 weeks and increased progressively to 93% of cases at term.

CONCLUSIONS

Fetal breathing movements are a complex phenomenon with a composite, progressive pattern of development during gestation.

Effect of adeno-associated virus-specific immunoglobulin G in human amniotic fluid on gene transfer

Intra-amniotic administration of adeno-associated virus (AAV) vector may be an effective way to deliver gene therapy for treatment of congenital pulmonary and intestinal disorders. In an effort to understand potential barriers to intra-amniotic gene therapy better, we determined whether human amniotic fluid (AF) could act as an inhibitor of AAV2-mediated gene transfer. AF samples were obtained from 21 different human pregnancies during routine amniocentesis at 16-20 weeks of gestation. An immortalized fetal human tracheal epithelial cell line (FHTE) was infected with AAV2 containing a luciferase reporter gene driven by the SV40 promoter in the presence and absence of each AF sample. Inhibition of transgene expression was observed in 8 (38%) of the AF samples (inhibitory AF) and resulted in luciferase levels of only 1.4% +/- 0.6% of those obtained with infection in normal media. Infections in 13 samples (62%) resulted in transgene expression comparable or in excess of infection in media alone (noninhibitory AF). Removal of immunoglobulin G (IgG) from inhibitory AF samples with Protein A returned luciferase expression to control levels (119% +/- 37% of control), suggesting the possible presence of inhibiting antibody. Eleven of the AF samples were evaluated by enzyme-linked immunosorbent assay (ELISA) for specific anti-AAV antibodies. All noninhibitory AF samples were negative (titers of < 1:20; n = 3), and 6 of the 8 inhibitory samples contained specific anti-AAV antibodies at titers ranging from 1:40 to 1:160. These studies demonstrate that AF from some individuals contains AAV-specific IgG that can inhibit gene transfer.

Power Doppler imaging of the fetal upper aerodigestive tract using a 4-point standardized evaluation: preliminary report

OBJECTIVE

Our investigation of fetal swallowing has identified potential limitations in the use of color Doppler imaging for detection of amniotic fluid flow and discrimination of respiratory from ingestive activity. The objective of this study was to evaluate an alternative imaging modality, power Doppler sonography, as a technique to enhance detection of amniotic fluid flow in the upper aerodigestive tract.

METHODS

We applied a standardized 4-axis sonographic examination of upper aerodigestive structures and used power Doppler imaging to document amniotic fluid flow. Normal aerodigestive activities from 62 healthy control subjects were compared with 4 abnormal cases.

RESULTS

Our longitudinal experience with 66 subjects showed that a directed evaluation of the fetal upper aerodigestive tract with power Doppler imaging provided a systematic approach for studying the physiologic development of this region in both healthy and at-risk fetuses.

CONCLUSIONS

A standardized 4-axis examination with power Doppler imaging is a useful adjunct in addressing ingestive and respiratory functions in the developing fetus.

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.

DESIGN

Prospective cross-sectional study.

SETTING

Fetal medicine unit at the Charité University Hospital in Berlin.

METHODS

Assessment of tracheal fluid flow was attempted in 340 healthy fetuses (GA 20-40 weeks) in which fetal breathing movements were seen by B-mode scan. Colour Doppler was applied to visualise the tracheal fluid flow, followed by spectral Doppler to record the velocity waveforms. The records of 53 fetuses divided into five gestational age groups (20-23, 24-27, 28-31, 32-35 and 36-40 weeks of gestation) containing 40 or more continuous breathing cycles (inspiration and expiration) were considered for analysis. Only regular breathing phases were examined and the volume obtained by integration of the tracheal fluid flow displaced during fetal breathing movements was calculated.

RESULTS

The intra-tracheal flow volume moved during inspiration (Vi) and expiration (Ve) increased until 36 weeks of gestation after which there was a flattening until term. This suggests either a reduction of lung liquid production or a diminished lung liquid volume. The median difference between Vi and Ve was positive in the first four age groups and negative in the last one suggesting that, in mature fetuses, the effect of fetal breathing movements no longer results in an influx.

CONCLUSIONS

Our data demonstrate a modification in fetal behaviour that manifests itself during the last four weeks before birth and has the potential to reduce lung liquid volume.

In utero AAV-mediated gene transfer to rabbit pulmonary epithelium

In utero intra-amniotic administration of adeno-associated virus (AAV) for treatment of cystic fibrosis (CF) has the potential to be an efficient way to target the rapidly dividing undifferentiated cells of the fetal pulmonary epithelium, while simultaneously treating other tissues involved in CF (such as the intestines), but has never before been studied. Intra-amniotic administration of 1x10(12) particles of AAV-luciferase vector to 110 fetal rabbits at 24-25 days gestation resulted in transgene expression in amniotic membranes, trachea, and pulmonary epithelium. The highest level of transgene expression was found in amniotic membranes. Transgene expression peaked in the lungs 10 days after vector delivery, decreased at day 17, and was no longer detectable after 24 days. The number of pulmonary cells transduced was approximately 1 in 500 and immunohistochemical analysis showed expression in varying cell types, including alveolar cells. Transgene expression was not detected in fetal rabbit intestines, skin or liver, nor in maternal ovaries or liver. Intra-amniotic administration of AAV does not result in the tissue inflammation and fetal loss previously documented with in utero adenoviral administration, and results in high levels of transgene expression in amniotic membranes with lower levels in fetal pulmonary epithelium.

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.

Assessment of fetal nasal fluid flow by two-dimensional color Doppler ultrasonography during pregnancy

OBJECTIVE

The purpose of this study was to evaluate the development of fetal lung function during normal pregnancy by analysis of breathing movement-related fetal nasal fluid flow waveforms including its regularity and inspiratory peak velocity using two-dimensional color Doppler and pulse Doppler ultrasonography.

METHODS

Sixty-eight normal fetuses between 26 and 39 weeks of gestation were examined. Breathing movement-related fetal nasal fluid flow waveforms were recorded. Regularity, frequency, and inspiratory fetal nasal fluid flow peak velocity and transverse lung area were measured. The relationships of these parameters were analyzed.

RESULTS

A regular pattern of breathing movement-related fetal nasal fluid flow waveforms appeared at 28 weeks of gestation and the appearance of a regular pattern increased to term. In 31 cases there was a regular pattern: frequency of fetal nasal fluid flow decreased and the peak flow velocity increased with advancing gestational age. Positive correlation between inspiratory fetal nasal fluid flow peak velocity and both gestational age and fetal transverse lung area was found.

CONCLUSIONS

The changes in inspiratory fetal nasal fluid flow peak velocity depend on structural and functional maturation with advancing gestation. The measurement of breathing-movement related fetal nasal fluid flow waveforms using two-dimensional color Doppler ultrasonography appears useful for evaluating fetal lung function.

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.

Fetal pulmonary development: the role of respiratory movements

The lung develops before birth as a collapsible, liquid-filled, organ. Throughout the later stages of gestation the fetal lungs are maintained at a level of expansion that is considerably greater than the level achieved as a result of passive equilibration between lung recoil and the chest wall. Fetal breathing movements (FBM) are a feature of normal fetal life and, as such, are used clinically in the assessment of fetal wellbeing. By opposing lung recoil, FBM help to maintain the high level of lung expansion that is now known to be essential for normal growth and structural maturation of the fetal lungs. During 'apnoeic' periods between successive episodes of FBM, active laryngeal constriction has the effect of opposing lung recoil by resisting the escape of lung liquid via the trachea. The prolonged absence or impairment of FBM is likely to result in a reduced mean level of lung expansion which can lead to hypoplasia of the lungs. There is clinical evidence, disputed by some, that the absence of FBM exacerbates the effects of other factors that are associated with lung hypoplasia, such as premature rupture of fetal membranes and oligohydramnios. Even in the absence of such factors, prolonged or repeated reductions or abolition of FBM may contribute to impairments of fetal lung development; FBM can be inhibited by fetal hypoxaemia, hypoglycaemia, maternal alcohol consumption, maternal smoking, intra-amniotic infection and maternal consumption of sedatives or narcotic drugs. Abnormal growth of the fetal lungs has relevance for postnatal respiratory health as it is now recognised that there may be only a limited capacity after birth for the restoration of normal pulmonary architecture following impaired intra-uterine lung development.

Patterns of fetal perinasal fluid flow in cases of congenital diaphragmatic hernia

OBJECTIVE(S)

Our purpose was to expand the previous reported series of observations of fetal perinasal fluid flow in cases of antenatally diagnosed congenital diaphragmatic hernia, characterize the timing parameters of the fetal breath cycle, and define the relationship of fetal perinasal fluid flow and the diaphragmatic component of fetal breathing movements. Our hypothesis was that characteristics of diaphragm-related and nondiaphragm-related perinasal fluid flow and other breath cycle characteristics differ in cases of congenital diaphragmatic hernia compared with controls.

STUDY DESIGN

Fetal perinasal fluid flow velocity and fetal chest wall movements were studied in 24 cases of uncomplicated pregnancy, and flow was studied in 24 cases of antenatally diagnosed congenital diaphragmatic hernia at gestational ages ranging from 30 to 41 weeks. The examination of fetal perinasal fluid flow velocity was performed with use of an ultrasonography system applying color flow and spectral Doppler analysis. Breath-to-breath interval, time of inspiration, time of expiration, and peak inspiratory and expiratory velocities were determined for each type of perinasal flow.

RESULTS

The study revealed that the time of expiration in cases of congenital diaphragmatic hernia at 30 to 36 and 37 to 41 weeks of gestation was significantly shorter than in cases of uncomplicated pregnancy. The ratio of time of inspiration and breath-to-breath interval in cases of diaphragmatic hernia was approximately 30% higher (p = 0.001) at 30 to 36 weeks of gestation than in cases of uncomplicated pregnancy. The study also showed that in cases of congenital diaphragmatic hernia the expiratory peak velocity ratio at 30 to 36 weeks of gestation was significantly lower than in cases of uncomplicated pregnancy.

CONCLUSIONS

We conclude that by Doppler ultrasonography measurements of fetal perinasal fluid flow, in cases of congenital diaphragmatic hernia, we can evaluate the timing parameters of fetal diaphragm-related breath cycles, the relationship of intraalveolar and intraamniotic pressures, and fetal upper respiratory tract resistance. Fetuses with diaphragmatic hernia spent significantly more time with diaphragm-nonrelated perinasal flow than did fetuses in cases of uncomplicated pregnancy, which can cause the increased loss of lung liquid and consequently be associated with pulmonary insufficiency in the early neonatal period.

Midtrimester premature rupture of the membranes

Midtrimester premature rupture of the membranes is an uncommon adverse complication of pregnancy with an occurrence of approximately 0.65%. Significant perinatal and maternal morbidity includes pulmonary hypoplasia, restriction deformities, and sequelae of prematurity as well as maternal chorioamnionitis and endometritis. Moreover, 31% of survivors are affected by long-term complications such as chronic lung disease, neurological and developmental abnormalities. Fetal survival is evident with increasing latency and good residual amniotic fluid (largest vertical pocket > or = 2 cm). In this article, we review the relevant literature regarding prognosis, counseling, and management of the patient with membrane rupture in the midtrimester.

Vagal tone during quiet sleep in normal human term fetuses

The purpose of this paper was to calculate vagal tone (V) for 17 normal human fetuses in quiet sleep (QS) between 36 and 40 weeks gestation. The fetal cardiac electrical signal was captured transabdominally in 3-min blocks at a rate of 833 times per second and fetal R-waves were extracted using adaptive signal processing techniques. Fetal R-wave interbeat intervals were converted to equally spaced, time-based data, and the low-frequency component was removed using a 21-point third-order moving polynomial. The parameter V was calculated by taking the natural logarithm of the sum of the power densities between 0.3 Hz and 1.3 Hz. We found that fetal breathing was associated with an approximately 25% increase in V as compared to nonbreathing, 3.33 +/- 0.48 versus 2.57 +/- 0.47, p < 0.0001. Furthermore, there was a significant linear relationship between the mean single-fetus V during spontaneous respiration and the mean single-fetus V during normally occurring apneic periods, r = 0.772, p < 0.002. We conclude that respiratory activity is associated with a significant increase in vagal tone for normal human fetuses in QS.

Fetal breathing characteristics and postnatal outcome in cases of congenital diaphragmatic hernia

OBJECTIVE

Our purpose was to determine characteristics of fetal breathing activity by recording fetal nasal fluid flow velocity in cases of congenital diaphragmatic hernia.

STUDY DESIGN

Fetal breathing-related nasal fluid flow was studied in 47 patients at 34 to 41 weeks of gestation, 16 cases of antenatally diagnosed congenital diaphragmatic hernia and 31 cases of uncomplicated pregnancy. The examination was performed by ultrasonography combined with color-flow and spectral Doppler analysis. An average of 25 breath cycles from each case was determined for each of the following timing parameters: breath-to-breath interval, time of inspiration, time of expiration, and ratio of time of inspiration and time of expiration.

RESULTS

In all cases with uncomplicated pregnancy fetal breathing-related nasal fluid flow was seen at the level of the nose, and the timing components of this flow were determined as control values. In two cases with diaphragmatic hernia no perinasal flow was demonstrated, although fetal breathing movements observed as chest wall movements were present. The other 14 cases with congenital diaphragmatic hernia who demonstrated perinasal flow had the following postnatal outcome: one stillbirth, five neonatal deaths (group I), and eight survived and were discharged (group II). The study revealed that the time of expiration (in milliseconds) in group II (493.2 +/- 34.3 SEM) was significantly (p = 0.0030) shorter than in group I (653.4 +/- 38.4) and in cases of uncomplicated pregnancy (633.6 +/- 18.5). The value of the time of inspiration/time of expiration ratio in group II was approximately 15% higher than in group I and approximately 30% higher than in cases of uncomplicated pregnancies.

CONCLUSIONS

Observation of fetal breathing-related nasal fluid flow velocity in cases of antenatally diagnosed congenital diaphragmatic hernia provides a rationale for the hypothesis that time of expiration and the time of inspiration/time of expiration ratio may be useful in the prediction of postnatal outcome. We speculate that the changes in the group of survivors may represent a compensatory phenomenon by causing intermittent changes in the volume of fluid within the lungs.