Percutaneous fetal endoscopic tracheal occlusion (FETO) for severe left-sided congenital diaphragmatic hernia

The TOTAL trial dilemma: A survey among professionals on equipoise regarding fetal therapy for severe congenital diaphragmatic hernia

OBJECTIVE

Running randomized clinical trials (RCT) in fetal therapy is challenging. This is no different for fetoscopic endoluminal tracheal occlusion (FETO) for severe left-sided Congenital Diaphragmatic Hernia (CDH). We assessed the knowledge, attitude and practice (KAP) of maternal-fetal medicine specialists toward the antenatal management of CDH, and the randomized controlled clinical (RCT) "Tracheal Occlusion To Accelerate Lung growth-trial."

METHODS

A cross-sectional KAP-survey was conducted among 311 registrants of the 18th World Congress in Fetal Medicine.

RESULTS

The overall knowledge of CDH and FETO was high. Remarkably only 45% considers prenatal prediction of neonatal outcome reliable. Despite, in their clinical practice they perform severity assessment (80%) and refer families for FETO either within the context of an RCT (43%) or on patient request (32%). Seventy percent perceives not offering FETO on patient demand seems as if no treatment is provided to a fetus with predicted poor outcome. Only 20% of respondents considers denying access to FETO on patient demand not as a psychological burden.

CONCLUSION

Often the views of individual respondents contradicted with their clinical practice. It seems that, for severe CDH, clinicians face personal and practical dilemmas that undermine equipoise. To us, this indicates the tension between the clinical and scientific obligations physicians experience.

A multicentre study to predict neonatal survival according to lung-to-head ratio and liver herniation in fetuses with left congenital diaphragmatic hernia (CDH): Hidden mortality from the Latin American CDH Study Group Registry

OBJECTIVE

To evaluate natural history of fetuses congenital diaphragmatic hernia (CDH) prenatally diagnosed in countries where termination of pregnancy is not legally allowed and to predict neonatal survival according to lung area and liver herniation.

METHODS

Prospective study including antenatally diagnosed CDH cases managed expectantly during pregnancy in six tertiary Latin American centres. The contribution of the observed/expected lung-to-head ratio (O/E-LHR) and liver herniation in predicting neonatal survival was assessed.

RESULTS

From the total population of 380 CDH cases, 144 isolated fetuses were selected showing an overall survival rate of 31.9% (46/144). Survivors showed significantly higher O/E-LHR (56.5% vs 34.9%; P < .001), lower proportion of liver herniation (34.8% vs 80.6%, P < .001), and higher gestational age at birth (37.8 vs 36.2 weeks, P < 0.01) than nonsurvivors. Fetuses with an O/E-LHR less than 35% showed a 3.4% of survival; those with an O/E-LHR between 35% and 45% showed 28% of survival with liver up and 50% with liver down; those with an O/E-LHR greater than 45% showed 50% of survival rate with liver up and 76.9% with liver down.

CONCLUSIONS

Neonatal mortality in CDH is higher in Latin American countries. The category of lung hypoplasia should be classified according to the survival rates in our Latin American CDH registry.

Maternal complications following open and fetoscopic fetal surgery: A systematic review and meta-analysis

OBJECTIVE

To establish maternal complication rates for fetoscopic or open fetal surgery.

METHODS

We conducted a systematic literature review for studies of fetoscopic or open fetal surgery performed since 1990, recording maternal complications during fetal surgery, the remainder of pregnancy, delivery, and after the index pregnancy.

RESULTS

One hundred sixty-six studies were included, reporting outcomes for open fetal (n = 1193 patients) and fetoscopic surgery (n = 9403 patients). No maternal deaths were reported. The risk of any maternal complication in the index pregnancy was 20.9% (95%CI, 15.22-27.13) for open fetal and 6.2% (95%CI, 4.93-7.49) for fetoscopic surgery. For severe maternal complications (grades III to V Clavien-Dindo classification of surgical complications), the risk was 4.5% (95% CI 3.24-5.98) for open fetal and 1.7% (95% CI, 1.19-2.20) for fetoscopic surgery. In subsequent pregnancies, open fetal surgery increased the risk of preterm birth but not uterine dehiscence or rupture. Nearly one quarter of reviewed studies (n = 175, 23.3%) was excluded for failing to report the presence or absence of maternal complications.

CONCLUSIONS

Maternal complications occur in 6.2% fetoscopic and 20.9% open fetal surgeries, with serious maternal complications in 1.7% fetoscopic and 4.5% open procedures. Reporting of maternal complications is variable. To properly quantify maternal risks, outcomes should be reported consistently across all fetal surgery studies.

Prenatal diagnosis and management of congenital diaphragmatic hernia

Congenital diaphragmatic hernia is characterized by failed closure of the diaphragm, thereby allowing abdominal viscera to herniate into the thoracic cavity and subsequently interfering with normal lung development. At birth, pulmonary hypoplasia leads to respiratory insufficiency and persistent pulmonary hypertension (PHT), that is lethal in up to 32% of patients. In isolated cases, the outcome may be predicted prenatally by medical imaging and advanced genetic testing. In those fetuses with a predicted poor outcome, fetoscopic endoluminal tracheal occlusion may be offered. This procedure is currently being evaluated in a global randomized clinical trial (www.TOTALtrial.eu). We are currently investigating alternative strategies including transplacental sildenafil administration to reduce the occurrence of persistent PHT.

Fetal Surgery and Delayed Cord Clamping: Neonatal Implications

Advances made in the last several decades in the care of the fetus and newborn have had a significant impact on morbidity and mortality. Delayed umbilical cord clamping in the preterm newborn results in fewer transfusions for anemia, decreased intraventricular hemorrhage, and decreased necrotizing enterocolitis. Because of advances made in fetal ultrasound diagnosis and technological advances, fetal surgeries to treat congenital diaphragmatic hernia, myelomeningocele, twin-to-twin transfusion syndrome, fetal lower urinary tract obstructions, amniotic band syndrome, and congenital cystic adenoid malformation or congenital pulmonary airway malformations have improved the quality of life and survival for these patients.

MicroRNA 200b is upregulated in the lungs of fetal rabbits with surgically induced diaphragmatic hernia

OBJECTIVE

Profiling of miR-200b expression and its targets (transforming growth factor [TGF]-β2 and ZEB2) in the surgical rabbit congenital diaphragmatic hernia (DH) model before and after tracheal occlusion (TO).

METHODS

Thirty-eight timed-pregnant rabbits had left DH creation on gestational day (GD) 23. On GD28, 17 randomly selected fetuses had TO. We harvested fetuses at GD23, GD28, or GD30. We calculated lung-to-body weight ratios, processed lungs for miR-200b in situ hybridization and real-time quantitative polymerase chain reaction, and evaluated effects on downstream targets TGF-β2 or ZEB2.

RESULTS

We obtained 16 DH fetuses (n = 7 GD28 and n = 9 GD30), 13 TO fetuses (GD30), and 38 control fetuses (n = 15 GD23, n = 11 GD28, and n = 12 GD30). Diaphragmatic hernia lungs were hypoplastic, and TO resulted in control lung-to-body weight ratio levels. Term miR-200b-3p levels were significantly upregulated in the hypoplastic compared with control ipsilateral lung (1.906 ± 0.90 vs 0.7429 ± 0.44) (P < .01). Fetal TO ipsilateral lungs displayed a variable miR-200b response on in situ hybridization and polymerase chain reaction, with levels similar to control and congenital DH lungs. The TGF-β2 was unchanged in hypoplastic and TO lungs, and ZEB2 tended to be reduced in TO compared with DH lungs (1.79 [0.4-2.9] vs 0.73 [0.5-1.4]).

CONCLUSIONS

Hypoplastic fetal rabbit lungs display upregulation of miR-200b expression although downstream targets are not different from controls. Following TO, fetal rabbit lungs display a variable miR-200b response.

Current and future antenatal management of isolated congenital diaphragmatic hernia

Congenital diaphragmatic hernia is surgically correctable, yet the poor lung development determines mortality and morbidity. In isolated cases the outcome may be predicted prenatally by medical imaging. Cases with a poor prognosis could be treated before birth. However, prenatal modulation of lung development remains experimental. Fetoscopic endoluminal tracheal occlusion triggers lung growth and is currently being evaluated in a global clinical trial. Prenatal transplacental sildenafil administration may in due course be a therapeutic approach, reducing the occurrence of persistent pulmonary hypertension, either alone or in combination with fetal surgery.

Clinically relevant discordances identified after tertiary reassessment of fetuses with isolated congenital diaphragmatic hernia

OBJECTIVE

Fetoscopic endoluminal tracheal occlusion (FETO) may improve outcome of severe isolated congenital diaphragmatic hernia (iCDH). We aimed to identify any discrepancy between initial assessment at the referring hospital and the evaluation at the fetal surgery center, and to document parental decisions following counseling for fetal surgery.

DESIGN

Single center retrospective study on patients with presumed iCDH either referred for assessment and counseling or referred for fetal surgery. Discordant findings were defined as either a >10% difference in lung size, discordant liver position or associated anomalies.

RESULTS

Outcomes from 129 consecutive assessments over 24 months were analyzed. Among fetal surgery referrals, 2% did not have CDH, and 10% had undiagnosed associated anomalies. Liver position was discordant in 7%. Thirty-three per cent had discordant lung size. Ninety-four per cent of patients eligible for surgery underwent FETO. In patients referred because of suspicion of CDH, associated anomalies were found in 14%. Fetal liver and lung assessments were discordant in 50% resp. 38%. Of those patients eligible for FETO, 26% requested termination. For three patients, the postnatal course was marked by a genetic or syndromic additional diagnosis.

CONCLUSION

Discordances between initial assessment before referral and evaluation in our institution were frequent, some of them clinically relevant. © 2017 John Wiley & Sons, Ltd.

[Fetoscopic tracheal occlusion for severe congenital diaphragmatic hernia: retrospective study]

BACKGROUND AND OBJECTIVES

The temporary fetal tracheal occlusion performed by fetoscopy accelerates lung development and reduces neonatal mortality. The aim of this paper is to present an anesthetic experience in pregnant women, whose fetuses have diaphragmatic hernia, undergoing fetoscopic tracheal occlusion (FETO).

METHOD

Retrospective, descriptive study, approved by the Institutional Ethics Committee. Data were obtained from medical and anesthetic records.

RESULTS

FETO was performed in 28 pregnant women. Demographic characteristics: age 29.8±6.5; weight 68.64±12.26; ASA I and II. Obstetric: IG 26.1±1.10 weeks (in FETO); 32.86±1.58 (reversal of occlusion); 34.96±2.78 (delivery). Delivery: cesarean section, vaginal delivery. Fetal data: Weight (g) in the occlusion and delivery times, respectively (1045.82±222.2 and 2294±553); RPC in FETO and reversal of occlusion: 0.7±0.15 and 1.32±0.34, respectively. Preoperative maternal anesthesia included ranitidine and metoclopramide, nifedipine (VO) and indomethacin (rectal). Preanesthetic medication with midazolam IV. Anesthetic techniques: combination of 0.5% hyperbaric bupivacaine (5-10mg) and sufentanil; continuous epidural predominantly with 0.5% bupivacaine associated with sufentanil, fentanyl, or morphine; general. In 8 cases, there was need to complement via catheter, with 5 submitted to PC and 3 to BC. Thirteen patients required intraoperative sedation; ephedrine was used in 15 patients. Fetal Anesthesia: fentanyl 10 to 20mg·kg^-1 and pancuronium 0,1-0,2mg·kg^-1 (IM). Neonatal survival rate was 60.7%.

CONCLUSION

FETO is a minimally invasive technique for severe congenital diaphragmatic hernia repair. Combined blockade associated with sedation and fetal anesthesia proved safe and effective for tracheal occlusion.

Fertility, pregnancy and gynecological outcomes after fetoscopic surgery for congenital diaphragmatic hernia

STUDY QUESTION

What is the impact of fetoscopic surgery for isolated Congenital Diaphragmatic Hernia (CDH) on future reproductive and gynecological outcomes?

SUMMARY ANSWER

We did not observe an increase of obstetric or gynecological problems after fetoscopic surgery nor was there an increased risk for subsequent infertility.

WHAT IS KNOWN ALREADY

The reproductive and gynecological outcomes of patients undergoing open maternal-fetal surgery are known. The most relevant counseling items are the elevated risk for uterine dehiscence and rupture (up to 14%).

STUDY DESIGN, SIZE, DURATION

Bi-centric study over a 10-year period including 371 women carrying a fetus with isolated CDH either managed expectantly (n = 167) or operated in utero (n = 204).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Consenting patients filled out a survey with 23 questions (2 open and 21 multiple choice). Questionnaires were custom designed to obtain information on subsequent reproductive or gynecological problems as well as psychological impact.

MAIN RESULTS AND THE ROLE OF CHANCE

The response rate was 40% (147/371). More women in the FETO group attempted a subsequent pregnancy: 70% (62/89) when compared with 47% (27/58) in controls (P = 0.009). This coincided with a longer follow-up in the FETO group (76 versus 59 months; P < 0.001) and a lower survival rate in the index pregnancy (53 versus 72%; P = 0.028). There was no difference in the number of nulliparous or parous women, neither in the conception rate. In total, there were 129 subsequent pregnancies. Nobody reported secondary fertility problems. Four women in the FETO group and one in the control reported a congenital anomaly in a subsequent pregnancy. Twenty-one pregnancies were reported with at least one complication (FETO: 23% (14/60), controls 27% (7/26)). During delivery or in the post-partum period 11 patients reported at least 1 complication (FETO 17% (10/59), controls 4% (1/24)). New onset gynecological problems occurred in 14 participants (10%). None of these events were more likely in one or the other group. Psychological and emotional impacts were frequent in both the FETO (41%) and the control groups (46%) (P = 0.691).

LIMITATIONS, REASONS FOR CAUTION

The response rate was 40% (147/371), less than desired. The use of unvalidated self-reported outcomes may skew exact determination of the nature and severity of medical complications. The number of observations for uncommon events was low. The mean follow-up period to detect gynecological complications may be too short.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first evidence that fetoscopic surgery for CDH does not compromise future reproductive potential or obstetrical outcome when compared with expectant management. A pregnancy complicated by a serious congenital birth defect, such as CDH, frequently has a measurable psychological impact.

STUDY FUNDING/COMPETING INTEREST

The authors have no conflicts to declare. J.D. receives a fundamental clinical research grant of the Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO; 18.01207). A.C.E. is supported by the Erasmus+Program of the European Union (Framework agreement number 2013-0040; contract 1011990). This was presented at the 61st meeting of the Society of Gynaecologic Investigation, in Florence, March 2014 (F-111).

Differences in Outcomes in Prenatally Diagnosed Congenital Diaphragmatic Hernia Compared to Postnatal Detection: A Single-Center Experience

Objectives: To compare outcomes in pregnancies with a prenatal detection of congenital diaphragmatic hernia (CDH) with children diagnosed after birth, treated at the same institution, and to determine the ability to predict prognosis through measurements of the observed to expected lung-to-head ratio (O/E LHR). Methods: This is a retrospective review of all children with CDH treated at our institution during 2006-2014. We compared outcomes of infants referred for surgery after postnatal diagnosis with outcomes of infants with prenatally diagnosed CDH. Results: In the prenatal group, O/E LHR was significantly different between survivors and deceased patients, with a cutoff at 35% O/E LHR. Survival to discharge and 1-year survival were significantly higher in the postnatal group that required intubation within 24 h; i.e., 92 and 89% versus 85 and 73% in the prenatal group (p < 0.05). There was less need for extracorporeal membrane oxygenation (ECMO), 41 versus 60%, and patch, 41 versus 75% (p < 0.001), in the postnatal group with early diagnosis compared with the prenatal group, respectively. Conclusion: Children with prenatally diagnosed CDH represent a population with a more severe condition compared to infants diagnosed after birth. They have poorer outcomes with higher needs for ECMO or use of patch, and lower survival rates were observed at an O/E LHR below 35%.

Quantifying stretch and secretion in the embryonic lung: Implications for morphogenesis

Branching in the embryonic lung is controlled by a variety of morphogens. Mechanics is also believed to play a significant role in lung branching. The relative roles and interactions of these two broad factors are challenging to determine. We considered three hypotheses for explaining why tracheal occlusion triples branching with no overall increase in size. Both hypotheses are based on tracheal occlusion blocking the exit of secretions. (H1) Increased lumen pressure stretches tissues; stretch receptors at shoulders of growing tips increase local rate of branching. (H2) Blocking exit of secretions blocks advective transport of morphogens, leading to (H2a) increased overall concentration of morphogens or (H2b) increased flux of morphogens at specific locations. We constructed and analyzed computational models of tissue stretch and solute transport in a 3D lung geometry. Observed tissue stresses and stretches were predominantly in locations unrelated to subsequent branch locations, suggesting that tissue stretch (H1) is not the mechanism of enhancement of branching. Morphogen concentration in the mesenchyme (H2a) increased with tracheal occlusion, consistent with previously reported results. Morphogen flux at the epithelial surface (H2b) completely changed its distribution pattern when the trachea was occluded, tripling the number of locations at which it was elevated. Our results are consistent with the hypothesis that tracheal occlusion blocks outflow of secretions, leading to a higher number of high-flux locations at branching tips, in turn leading to a large increase in number of branching locations.

The normal growth of the tracheal wall in human foetuses

INTRODUCTION

Tracheal wall thickness is a substantial indicator in various pathological changes. The present study was performed to compile normative data and formulae for the tracheal wall thickness and volume at varying gestational age.

MATERIAL AND METHODS

Using anatomical dissection, digital image analysis and statistics a range of the wall thickness, proximal internal-to-external cross-sectional area ratio, and wall volume for the trachea in 73 spontaneously aborted human fetuses aged 14-25 weeks was examined.

RESULTS

No significant male-female differences were found. The values of tracheal wall thickness ranged from 0.36 ±0.01 mm for the 14-week group to 1.23 ±0.17 mm for the 25-week group of gestation, according to the linear function y = -0.823 + 0.083 × age ± 0.087. The tracheal lumen rate, expressed as the proximal internal-to-external cross-sectional area ratio, decreased from 42.61 ±1.11% to 26.78 ±4.95%, according to the function y = 62.239 - 1.487 × age ±3.119. The tracheal wall volume rose from 16.28 ±4.18 mm(3) in fetuses aged 14 weeks to 269.22 ±29.26 mm(3) in fetuses aged 25 weeks, according to the quintic function y = 0.000052 × age(4.894).

CONCLUSIONS

The tracheal wall parameters show no sexual dimorphism. The tracheal wall grows linearly in its length, and according to a quintic function in its volume. A relative decrease in the tracheal lumen at the expense of an increase in both the wall thickness and wall volume of the trachea is found during gestation.

Early fetoscopic tracheal occlusion for extremely severe pulmonary hypoplasia in isolated congenital diaphragmatic hernia: preliminary results

OBJECTIVE

To evaluate the effect of early fetoscopic tracheal occlusion (FETO) (22-24 weeks' gestation) on pulmonary response and neonatal survival in cases of extremely severe isolated congenital diaphragmatic hernia (CDH).

METHODS

This was a multicenter study involving fetuses with extremely severe CDH (lung-to-head ratio < 0.70, liver herniation into the thoracic cavity and no other detectable anomalies). Between August 2010 and December 2011, eight fetuses underwent early FETO. Data were compared with nine fetuses that underwent standard FETO and 10 without fetoscopic procedure from January 2006 to July 2010. FETO was performed under maternal epidural anesthesia, supplemented with fetal intramuscular anesthesia. Fetal lung size and vascularity were evaluated by ultrasound before and every 2 weeks after FETO. Postnatal therapy was equivalent for both treated fetuses and controls. Primary outcome was infant survival to 180 days and secondary outcome was fetal pulmonary response.

RESULTS

Maternal and fetal demographic characteristics and obstetric complications were similar in the three groups (P > 0.05). Infant survival rate was significantly higher in the early FETO group (62.5%) compared with the standard group (11.1%) and with controls (0%) (P < 0.01). Early FETO resulted in a significant improvement in fetal lung size and pulmonary vascularity when compared with standard FETO (P < 0.01).

CONCLUSIONS

Early FETO may improve infant survival by further increases of lung size and pulmonary vascularity in cases with extremely severe pulmonary hypoplasia in isolated CDH. This study supports formal testing of the hypothesis with a randomized controlled trial.

Predictors of neonatal morbidity in fetuses with severe isolated congenital diaphragmatic hernia undergoing fetoscopic tracheal occlusion

OBJECTIVES

To investigate neonatal morbidity in fetuses with severe congenital diaphragmatic hernia (CDH) treated with fetoscopic endoluminal tracheal occlusion (FETO) and compare it with historical controls with less severe forms of CDH that were managed expectantly.

METHODS

This was a prospective, multicenter study on neonatal outcomes and prenatal predictors in 90 FETO survivors (78 left-sided, 12 right) and 41 controls from the antenatal CDH registry with either severe or moderate hypoplasia who were managed expectantly. We also investigated early neonatal morbidity indicators, including the need for patch repair, duration of mechanical ventilation and supplemental oxygen, age at full enteral feeding and incidence of pulmonary hypertension.

RESULTS

Gestational age at delivery was predictive of duration of assisted ventilation (P = 0.046), days on supplemental oxygen (P = 0.019) and age at full enteral feeding (P = 0.020). When delivery took place after 34 weeks' gestation, neonatal morbidity of FETO cases was comparable with that of expectantly managed cases with moderate hypoplasia.

CONCLUSIONS

Fetal intervention for severe CDH is associated with neonatal morbidity that is comparable with that of an expectantly managed group with less severe disease.

Novel patterns for the growing main bronchi in the human fetus: an anatomical, digital and statistical study

Purpose

Intensive progress in prenatal medicine results in performing airway management in the fetus affected by life-threatening congenital malformations. This study aimed to examine age-specific reference intervals and growth dynamics for length, proximal and distal external transverse diameters, and projection surface areas of the two main bronchi at varying gestational ages, including their relative growth in length and projection surface area.

Materials and methods

Using anatomical dissection, digital image analysis and statistics, length, proximal and distal external transverse diameters, and projection surface areas of the right and left main bronchi were examined in 73 human fetuses (39 males, 34 females) aged 14–25 weeks, derived from spontaneous abortions and stillbirths.

Results

Statistical analysis showed no sex differences. Between the 14 and 25th week of gestation, the lengths of the right and left main bronchi increased from 1.43 ± 0.18 to 3.18 ± 0.39 mm, and from 2.97 ± 0.16 to 7.58 ± 1.95 mm, in accordance with the functions: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 4.850 + 2.452 x \; \text{ln}\left( {\text{Age}} \right) \pm 0.400\;{\text{and}}\;y = - 15.005 + 7.093x \; \text{ln} \left( {\text{Age}} \right) \pm 0.579 $$\end{document}y=−4.850+2.452xln(Age)±0.400andy=−15.005+7.093xln(Age)±0.579, respectively. The proximal external transverse diameters of the right and left main bronchi varied from 2.13 ± 0.41 to 4.24 ± 0.20 mm, and from 1.84 ± 0.06 to 3.67 ± 0.66 mm, following the logarithmic models: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 8.666 + 4.018x \; \text{ln}{\rm (Age)} \pm 0.367\;{\text{and}}\;y = - 6.938 + 3.305x{\text{ ln(Age) }} \pm 0.323 $$\end{document}y=−8.666+4.018xln(Age)±0.367andy=−6.938+3.305xln(Age)±0.323, respectively. The distal external transverse diameter rose from 2.09 ± 0.47 to 4.24 ± 0.20 mm, as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 8.723 + 4.021x{\text{ ln(Age)}} \pm 0.392 $$\end{document}y=−8.723+4.021xln(Age)±0.392 for the right main bronchus, and from 1.85 ± 0.04 to 3.67 ± 0.66 mm, like \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 6.924 + 3.280x{\text{ ln(Age)}} \pm 0.348 $$\end{document}y=−6.924+3.280xln(Age)±0.348 for the left one. On either side, there were no statistically significant differences between values of the proximal and distal transverse diameters of the main bronchus. The projection surface areas of the right and left main bronchi ranged from 2.95 ± 0.19 to 13.34 ± 2.12 mm², and from 5.57 ± 0.21 to 28.52 ± 5.24 mm², as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 10.212 + 0.943x{\text{ Age}} \pm 1.739 $$\end{document}y=−10.212+0.943xAge±1.739 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 19.119 + 1.875x{\text{ Age}} \pm 3.054 $$\end{document}y=−19.119+1.875xAge±3.054. The two main bronchi revealed a proportionate increase in both length and projection surface area, since the right-to-left bronchial length ratio and the right-to-left bronchial projection surface area ratio were stable, 0.41 ± 0.07 and 0.47 ± 0.08, respectively, throughout the analyzed period.

Conclusions

The main bronchi show no sex differences. The right and left main bronchi grow logarithmically in length and external transverse diameter, and linearly in projection surface area. The right and left main bronchi evolve proportionately, with the right-to-left bronchial ratios of 0.41 ± 0.07 for length, and 0.47 ± 0.08 for projection surface area.

Usefulness of lung-to-head ratio and intrapulmonary arterial Doppler in predicting neonatal morbidity in fetuses with congenital diaphragmatic hernia treated with fetoscopic tracheal occlusion

OBJECTIVE

To explore the potential value of intrapulmonary artery Doppler velocimetry in predicting neonatal morbidity in fetuses with left-sided congenital diaphragmatic hernia (CDH) treated with fetoscopic tracheal occlusion (FETO).

METHODS

Observed/expected lung-to-head ratio (O/E-LHR), and intrapulmonary Doppler pulsatility index and peak early-diastolic reversed flow were evaluated within 24 h before FETO in a consecutive cohort of 51 fetuses with left-sided CDH at between 24 and 33 weeks' gestation. Lung Doppler parameters were converted into Z-scores and defined as abnormal if the pulsatility index had a Z-score of > 1.0 or the peak early-diastolic reversed flow had a Z-score of > 3.5. The association of O/E-LHR and Doppler velocimetry with neonatal outcome was assessed using multiple linear or logistic regression analysis adjusted for gestational age at birth.

RESULTS

Among the 26 fetuses that survived, 18 (69.2%) had normal and eight (30.8%) had abnormal Doppler values. O/E-LHR was not associated with neonatal morbidity in surviving fetuses. Compared with the group with normal Doppler parameters, cases with abnormal intrapulmonary Doppler were associated with a significant increase in the duration of mechanical ventilation (average increase of 21.2 (95% CI, 9.99-32.5) days; P < 0.01), conventional ventilation (15.2 (95% CI, 7.43-23.0) days; P < 0.01), high-frequency ventilation (6.34 (95% CI, 0.69-11.99) days; P < 0.05), nitric oxide therapy (5.73 (95% CI, 0.60-10.9) days; P < 0.05), oxygen support (36.5 (95% CI, 16.3-56.7) days; P < 0.01), parenteral nutrition (19.1 (95% CI, 7.53-30.7) days; P < 0.01) and stay in neonatal intensive care unit (42.7 (95% CI, 22.9-62.6) days; P < 0.001), and with significantly higher rates of high-frequency ventilation (87.5 vs. 44.4%;P < 0.05), oxygen requirement at 28 days of age (75.0 vs. 11.1%; P < 0.01), gastroesophageal reflux (62.5 vs. 22.2%; P < 0.05) and tube feeding at discharge (37.5 vs. 5.56%; P < 0.05).

CONCLUSION

As previously reported, O/E-LHR did not predict neonatal morbidity. In contrast, intrapulmonary artery Doppler evaluation was predictive of neonatal morbidity in CDH fetuses treated with FETO.

New quantitative patterns of the growing trachea in human fetuses

BACKGROUND

Rapid progress in perinatal medicine has resulted in numerous tracheo-bronchial interventions on fetal and neonatal airways. The present study was performed to compile normative data for tracheal dimensions at varying gestational ages.

MATERIAL/METHODS

Using anatomical dissection, digital image analysis (NIS-Elements BR 3.0) and statistical analysis (Wilcoxon signed-rank test, Student's t test, one-way ANOVA, post-hoc Bonferroni test, linear and nonlinear regression analysis) a range of the 4 variables (length in mm, middle external transverse diameter in mm, proximal internal cross-sectional area in mm², internal volume in mm³) for the trachea in 73 spontaneously aborted human fetuses (39 male, 34 female) aged 14-25 weeks was examined.

RESULTS

No significant male-female differences were found (P>0.05). The length ranged from 10.37±2.15 to 26.54±0.26 mm as y=-65.098 + 28.796 × ln (Age) ±1.794 (R²=0.82). The middle external transverse diameter varied from 2.53±0.09 to 5.09±0.42 mm with the model y=-11.020 + 5.049 × ln (Age) ±0.330 (R²=0.81). The trachea indicated a proportional evolution because the middle external transverse diameter-to-length ratio was stable (0.23±0.03). The proximal internal cross-sectional area rose from 1.46±0.04 to 5.76±1.04 mm² as y=-3.562 + 0.352 × Age ±0.519 (R²=0.76). The internal volumetric growth from 11.89±2.49 to 119.63±4.95 mm³ generated the function y=-135.248 + 9.919 × Age ±10.478 (R²=0.86).

CONCLUSIONS

The growth in both length and middle external transverse diameter of the trachea follows logarithmic functions, whereas growth of both its proximal internal cross-sectional area and internal volume follow linear functions. The length and middle external transverse diameter of the trachea develop proportionally to each other. The tracheal dimensions may be helpful in the prenatal diagnosis and monitoring of tracheal malformations and obstructive anomalies of the upper respiratory tract.

Tracheal dimensions in human fetuses: an anatomical, digital and statistical study

PURPOSE

Rapid advances in perinatal medicine have resulted in increased number of various tracheo-bronchial interventions on fetal and neonatal airways. The present study was performed to compile normative data for external dimensions of the trachea at varying gestational age.

MATERIALS AND METHODS

Using anatomical dissection, digital image analysis (NIS-Elements BR 3.0) and statistical analysis (ANOVA, regression analysis), a range of measurements (prebifurcation and bifurcation lengths, proximal and distal external transverse diameters, proximal external cross-sectional area, and external volume) for the trachea in 73 spontaneously aborted fetuses (39 male, 34 female) aged 14-25 weeks was examined.

RESULTS

No significant male-female differences were found (P > 0.05). The prebifurcation and bifurcation lengths ranged from 8.14 ± 1.90 to 20.77 ± 0.50 mm and from 2.23 ± 0.25 to 5.77 ± 0.76 mm, according to the functions y = -54.291 + 23.940 × ln (Age) ± 1.681 (R (2) = 0.78) and y = -10.756 + 4.860 × ln (Age) ± 0.731 (R (2) = 0.44), respectively. Their relative growth, expressed as the bifurcation-to-prebifurcation length ratio, was stable from the age of 16 weeks and attained the value 0.22 ± 0.05. The proximal external transverse diameter of the trachea was greater (36 fetuses, 49.3%), smaller (34 fetuses, 46.6%) or similar (3 fetuses, 4.1%), when compared to the distal external transverse diameter. The values for proximal and distal transverse diameters ranged from 2.39 ± 0.04 to 5.20 ± 0.17 mm and from 2.42 ± 0.20 to 4.93 ± 0.08 mm, expressed by the functions: y = -9.659 + 4.574 × ln (Age) ± 0.313 (R (2) = 0.79) and y = -10.897 + 4.984 × ln (Age) ± 0.327 (R (2) = 0.81). The values of proximal external cross-sectional area ranged from 3.38 ± 0.12 to 15.98 ± 1.04 mm(2), according to the linear function y = -11.798 + 1.077 × Age ± 1.463 (R (2) = 0.78). The values of external volume of the trachea ranged from 34.3 ± 11.6 to 370.6 ± 94.1 mm(3) and generated the quadratic function y = -154.589 + 0.858 × Age(2) ± 34.196 (R (2) = 0.87).

CONCLUSIONS

The tracheal parameters do not show male-female differences. The developmental dynamics of prebifurcation and bifurcation lengths and proximal and distal external transverse diameters of the trachea follow linear functions dependent on the natural logarithm of fetal age, its external cross-sectional area-according to a linear function, and its external volume-according to a quadratic function.

Congenital diaphragmatic hernia: lung-to-head ratio and lung volume for prediction of outcome

OBJECTIVE

The purpose of this study was to evaluate observed/expected (O/E) lung-to-head ratio (LHR) by ultrasound (US) and total fetal lung volume (TFLV) by magnetic resonance imaging as neonatal outcome predictors in isolated fetal congenital diaphragmatic hernia (CDH).

STUDY DESIGN

We conducted a retrospective study of 72 fetuses with isolated CDH, in whom O/E LHR and TFLV were evaluated as survival predictors.

RESULTS

O/E LHR on US and O/E TFLV by magnetic resonance imaging were significantly lower in newborn infants with isolated CDH who died compared with survivors (30.3 ± 8.3 vs 44.2 ± 14.2; P < .0001 for O/E LHR; 21.9 ± 6.3 vs 41.5 ± 17.6; P = .001 for O/E TFLV). Area under receiver-operator characteristics curve for survival for O/E LHR was 0.80 (95% confidence interval, 0.70-0.90). On multivariate analysis, O/E LHR predicted survival, whereas hernia side and first neonatal pH did not. For each unit increase in O/E LHR, mortality odds decreased by 11% (95% confidence interval, 4-17%).

CONCLUSION

In fetuses with isolated CDH, O/E LHR (US) independently predicts survival and may predict severity, allowing management to be optimized.

Changes of laryngeal parameters during intrauterine life

Objective

Increased care of fetal and neonatal airways has led to advances in neonatal medicine. The early diagnosis and treatment of respiratory diseases require a detailed knowledge of fetal airway anatomy and development. The aim of this study was to determine the anatomical development of the thyroid and cricoid cartilages and their structural variability during fetal life.

Materials and methods

The study was performed on the thyroid and cricoid cartilages of 55 human fetal larynges of both sexes, between the ages of 13 and 27 weeks of intrauterine life. Numerous measurements of the thyroid and cricoid cartilages were performed.

Results

Correlations between the obtained results were calculated in relation to the crown-rump (C-R) length of human fetuses and to sex. The structural variability of the thyroid and cricoid cartilages of human male and female fetuses in subsequent weeks of intrauterine life was observed. In both genders a correlation between laryngeal size and fetal crown-rump length, regardless of sex, was found. The thyroid cartilage presents a sexual dimorphism.

Conclusions

The results of this study can be useful in the analysis of prenatal examinations, and in planning the treatment of airway emergencies.

Contribution of intrapulmonary artery Doppler to improve prediction of survival in fetuses with congenital diaphragmatic hernia treated with fetal endoscopic tracheal occlusion

OBJECTIVE

To evaluate the contribution of intrapulmonary artery Doppler in predicting the survival of fetuses with congenital diaphragmatic hernia (CDH) treated with fetoscopic tracheal occlusion (FETO).

METHODS

A cohort of 41 fetuses (between 24 and 28 weeks of gestation) with CDH was treated with FETO. The observed/expected lung-to-head ratio (O/E-LHR), pulmonary artery pulsatility index (PI), peak early diastolic reversed flow (PEDRF) and peak systolic velocity (PSV) were evaluated before FETO, and their isolated and combined value to predict survival using multiple logistic regression and decision-tree analysis was assessed.

RESULTS

O/E-LHR and intrapulmonary artery PI and PEDRF were significantly associated with the probability of survival (O/E-LHR > or = 26%, OR 14.2; PI < 1 Z-score, OR 8.4; and PEDRF < 3.5 Z-scores, OR 5.7). Decision-tree analysis showed that O/E-LHR was the best initial predictor of prognosis (O/E-LHR > or = 26%, 90% survival; O/E-LHR < 26%, 45% survival). For fetuses with an O/E-LHR of < 26%, Doppler parameters allowed discrimination of cases with moderate (66-71% survival) and very poor (0% survival) prognosis.

CONCLUSION

Intrapulmonary artery Doppler evaluation helps to refine the prediction of survival after FETO in fetuses with severe CDH.

Congenital diaphragmatic hernia in the neonatal period: review of 21 years' experience

BACKGROUND

Despite advances in therapeutic modalities, congenital diaphragmatic hernia (CDH) still accounts for significant neonatal mortality. This study aimed to describe the demographic features, clinical experiences of postnatal care, and differences between non-survivors and survivors with CDH.

METHODS

We retrospectively reviewed medical records of neonates with CDH admitted to Kaohsiung Chang Gung Memorial Hospital over a 21-year period. Neonates with diaphragmatic eventration and those transferred after surgery were excluded.

RESULTS

A total of 24 live-born neonates fulfilled the study criteria; 13 (54%) were boys and 11 (46%) were girls. Eight (33%) patients were prenatally diagnosed. The mean gestational age was 38.8 +/- 1.8 weeks (range, 35-41 weeks). Twenty-three (96%) had Bochdalek hernia [19 (83%) left-sided, 4 (17%) right-sided], and one (4%) had right-sided Morgagni hernia. Additional major congenital anomalies were identified in five patients (21%). The overall mortality was 21% (5/24); all deaths occurred before surgery. Statistically significant differences between survivors and non-survivors were found for right-sided CDH, low 1-minute and 5-minute Apgar scores, and low pH of the first arterial blood gas. Deaths were attributed to severe persistent pulmonary hypertension, unresponsiveness to aggressive resuscitation at birth, and major associated malformations.

CONCLUSION

Seventy-nine percent of our CDH patients survived to hospital discharge. Resuscitation by a skilled neonatology team to prevent low Apgar scores and low pH, careful evaluation of other anomalies, and overcoming pulmonary hypertension might improve the survival rate. Recognizing unfavorable factors in CDH may help clinicians manage the critical care of these babies.

Prenatal and early postnatal morphogenesis and growth of human laryngotracheal structures

Advances in neonatal medicine have resulted in increased care of fetal and neonatal airways. These advances have required an exhaustive knowledge of fetal airway anatomy and development. The aim of this study was to determine the anatomical development of laryngotracheal structures during the fetal and immediate postnatal period and to correlate these observations with other fetal biometric parameters to estimate developmental particularities of the fetal airway. An anatomical prospective study was based on examination of larynx and trachea from 300 routine autopsies of fetuses and infants, free of malformation and never intubated. Anatomical measurements of cricoid cartilage, thyroid cartilage, glottis, arytenoid cartilage and trachea were performed using a precision calliper and precision divider. Statistical analysis was performed to represent the growth of anatomical structures and to evaluate the correlation with biometric data. Raw data and 10th and 90th percentile curves were fitted satisfactorily with a linear model for gestational age. A linear relationship between laryngotracheal measurement and body weight and height was observed except for glottis length, interarytenoid distance and anterior cricoid height. The diameter of the cricoid lumen was significantly less than that of the trachea and glottis lumen. A sexual dysmorphism was noted for thyroid cartilage measurements and interarytenoid distance, with measurements significantly smaller in females. This study reports the anatomical development of normal laryngotracheal structures during the fetal period. Despite the fact that this study was performed during postmortem examination, these observations can be useful to develop criteria, materials and surgical procedures adapted to fetal and neonatal airways as well as for the purposes of early diagnosis and management of laryngotracheal malformations.

Lung organogenesis

Developmental lung biology is a field that has the potential for significant human impact: lung disease at the extremes of age continues to cause major morbidity and mortality worldwide. Understanding how the lung develops holds the promise that investigators can use this knowledge to aid lung repair and regeneration. In the decade since the "molecular embryology" of the lung was first comprehensively reviewed, new challenges have emerged-and it is on these that we focus the current review. Firstly, there is a critical need to understand the progenitor cell biology of the lung in order to exploit the potential of stem cells for the treatment of lung disease. Secondly, the current familiar descriptions of lung morphogenesis governed by growth and transcription factors need to be elaborated upon with the reinclusion and reconsideration of other factors, such as mechanics, in lung growth. Thirdly, efforts to parse the finer detail of lung bud signaling may need to be combined with broader consideration of overarching mechanisms that may be therapeutically easier to target: in this arena, we advance the proposal that looking at the lung in general (and branching in particular) in terms of clocks may yield unexpected benefits.

Commonly encountered surgical problems in the fetus and neonate

Neonatal surgical care requires a current understanding of pre- and postnatal intervention for a myriad of congenital anomalies. This article includes an update of the recent information on commonly encountered fetal and neonatal surgical problems, highlighting specific areas of controversy and challenges in diagnosis. The authors hope that this article is useful for trainees and practitioners involved in any aspect of fetal and neonatal care.

Changing perspectives on the perinatal management of isolated congenital diaphragmatic hernia in Europe

Congenital diaphragmatic hernia (CDH) should be diagnosed in the prenatal period and prompt referral to a tertiary referral center for imaging, genetic testing, and multidisciplinary counseling. Individual prediction of prognosis is based on the absence of additional anomalies, lung size, and liver herniation. In severe cases, a prenatal endotracheal balloon procedure is currently being offered at specialized centers. Fetal intervention is now also offered to milder cases within a trial, hypothesizing that this may reduce the occurrence of bronchopulmonary dysplasia in survivors. Postnatal management has been standardized by European high-volume centers for the purpose of this and other trials.

Frontotemporal dementia: change of familial caregiver burden and partner relation in a Dutch cohort of 63 patients

BACKGROUND/AIMS

The current study examined the change of caregiver burden and the development of the quality of the partner relation in frontotemporal dementia (FTD).

METHODS

During a 2-year period, deterioration, behavioural problems, caregiver burden, general psychopathology, quality of life, social support, coping strategies and relationship quality were inspected in 63 FTD caregiver-care recipient dyads.

RESULTS

After 2 years patients reached maximum dementia severity with stable Neuropsychiatric Inventory levels. Contrary to expectations, caregiver burden decreased and psychological well-being remained stable. Coping style and social support changed unfavourably. Relationship closeness and getting along were preserved, whereas communication and sharing viewpoint on life were dramatically reduced.

CONCLUSIONS

FTD caregivers need support in coping with the increasingly hopeless situation of their patients. Future research methods into caregiver burden should address response shift as a means for psychological adjustment.

Antenatal prediction of lung volume and in-utero treatment by fetal endoscopic tracheal occlusion in severe isolated congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a severe malformation with an overall survival between 30% and 90%. Survival in the presence of associated malformations is very low. The condition should be detected in ultrasound screening programmes, but whether and how prenatal imaging can accurately predict outcome remains a matter of debate. Predictions based on the lung area:head circumference ratio and liver position are best studied. This information is highly relevant in counselling patients, leaving to severe cases the option of termination of pregnancy as experimental prenatal intervention aiming to reverse pulmonary hypoplasia. The purpose of this review is to update current knowledge regarding predictive value of prenatal assessment in terms of neonatal survival. We will also discuss experimental evidence and clinical data regarding fetal tracheal occlusion.

Prenatal diagnosis, prediction of outcome and in utero therapy of isolated congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) can be associated with genetic or structural anomalies with poor prognosis. In isolated cases, survival is dependent on the degree of lung hypoplasia and liver position. Cases should be referred in utero to tertiary care centers familiar with this condition both for prediction of outcome as well as timed delivery. The best validated prognostic indicator is the lung area to head circumference ratio. Ultrasound is used to measure the lung area of the index case, which is then expressed as a proportion of what is expected normally (observed/expected LHR). When O/E LHR is < 25% survival chances are < 15%. Prenatal intervention, aiming to stimulate lung growth, can be achieved by temporary fetal endoscopic tracheal occlusion (FETO). A balloon is percutaneously inserted into the trachea at 26-28 weeks, and reversal of occlusion is planned at 34 weeks. Growing experience has demonstrated the feasibility and safety of the technique with a survival rate of about 50%. The lung response to, and outcome after FETO, is dependent on pre-existing lung size as well gestational age at birth. Early data show that FETO does not increase morbidity in survivors, when compared to historical controls. Several trials are currently under design.

Fetal tracheal occlusion for severe congenital diaphragmatic hernia in humans: a morphometric study of lung parenchyma and muscularization of pulmonary arterioles

OBJECTIVE

The aim of this study is to examine structure of lung parenchyma (Pp) and muscularization of pulmonary arterioles (PAs) in human fetuses that underwent tracheal occlusion (TO) therapy for severe congenital diaphragmatic hernia (CDH).

MATERIAL

Fifteen fetuses underwent TO, with 5 survivors (Am J Obstet Gynecol. 2000:183;1059-1066). Paraffin-embedded lung specimens from 7 of 10 nonsurvivors (CDH-TO) and 6 age-matched fetuses (CDH) were available for morphometric analysis, which included measurements of point fraction of lung Pp and surface density. The PAs were categorized according to external diameter (<70 microm and 70 <or= 140 microm). Percent medial wall thickness (%MWT) was calculated by dividing raw measurements of MWT by external diameter.

RESULTS

Gestational age at TO was 27.6 +/- 0.9 weeks with a mean duration of TO of 32.6 +/- 6.8 days. Gestational age at delivery (CDH-TO 31.9 +/- 0.9 vs CDH 35.4 +/- 1.8 weeks; P = .18) and postnatal survival time (CDH-TO 20.5 +/- 6.0 vs CDH 18.6 +/- 7.8 days; P = .85) were not significantly different between groups. Tracheal occlusion significantly increased the lung-to-body weight ratio (CDH-TO 13.0 +/- 2.2 vs CDH 6.6 +/- 0.9; P = .02). Tracheal occlusion tended to decrease right-lung Pp (CDH-TO 54.6% +/- 2.6% vs CDH 65.7% +/- 5.9%; P = .05), whereas left-lung Pp was not different between groups (CDH-TO 63.0% +/- 3.5% vs CDH 66.7% +/- 4.1%; P = .51). Surface density of airspaces was not different between groups in either left (CDH-TO 171.3 +/- 16.1 cm(-1) vs CDH 151.1 +/- 8.1 cm(-1); P = .34) or right (CDH-TO 172.0 +/- 10.6 cm(-1) vs CDH 160.8 +/- 3.6 cm(-1); P = .33) lungs. The %MWT in small and large PA was similar between groups.

CONCLUSIONS

Open prenatal TO in human fetuses increased lung growth, as evidenced by an increase in lung weight, but did not improve parenchymal structure or muscularization of PAs.

How useful is the lung-to-head ratio in predicting outcome in the fetus with congenital diaphragmatic hernia? A systematic review and meta-analysis

OBJECTIVE

Fetal surgery to improve lung growth comprises tracheal occlusion in selected 'high-risk' fetuses with congenital diaphragmatic hernia (CDH). Sonographically measured fetal lung-to-head ratio (LHR) is utilized to recruit candidates for fetal surgery. This study provides a meta-analysis of the evidence regarding the prognostic use of lung-to-head ratio measurements in fetal CDH.

METHODS

MEDLINE, SCOPUS and ISI PROCEEDINGS databases were searched for MeSH terms: lung, head, hernia and ratio. References in retrieved studies were also searched. Studies were categorized as follows: Phase I studies measured normal fetal LHR; Phase II studies compared fetal LHR in CDH survivors and non-survivors (if LHR informed therapy decisions or LHR was not measured during the window for intervention (< 32 weeks' gestation), studies were excluded); Phase III studies used LHR to guide selection for fetal surgery (non-randomized trials were excluded); Phase IV studies measured CDH survival before and after LHR application in clinical practice.

RESULTS

The one Phase I study showed that LHR varied substantially with gestation and technique. No complete studies met the selection criteria for Phase II: meta-analysis of subgroups revealed similar LHR in CDH survivors and non-survivors. A single Phase III study revealed no benefit for LHR-directed fetal surgery. No Phase IV studies were identified.

CONCLUSION

The prognostic use of LHR in fetal CDH entered clinical practice prior to publication of robust normal data and is not supported by current evidence. Application of a structured approach to any 'new' prognostic test could improve its validity and clinical application.

Exploiting mechanical stimuli to rescue growth of the hypoplastic lung

Impaired lung development afflicts a range of newborns cared for by paediatric surgeons. As a result the speciality has led in the development of surgical models that illustrate the biomechanical regulation of lung growth. Using transgenic mutants, biologists have similarly discovered much about the biochemical regulation of prenatal lung growth. Airway smooth muscle (ASM) and its prenatal contractility airway peristalsis (AP) represent a novel link between these areas: ASM progenitors produce an essential biochemical factor for lung morphogenesis, whilst calcium-driven biomechanical ASM activity appears to regulate the same. In this invited paper, I take the opportunity both to review our recent findings on lung growth and prenatal ASM, and also to discuss mechanisms by which ASM contractility can regulate growth. Finally, I will introduce some novel ideas for exploration: ASM contractility could help to schedule parturition (pulmonary parturition clock) and could even be a generic model for smooth muscle regulation of morphogenesis in similar organs.

Surfactant maturation is not delayed in human fetuses with diaphragmatic hernia

BACKGROUND

Pulmonary hypoplasia and persistent pulmonary hypertension account for significant mortality and morbidity in neonates with congenital diaphragmatic hernia (CDH). Global lung immaturity and studies in animal models suggest the presence of surfactant deficiency that may further complicate the pathophysiology of CDH. However, data about surfactant status in human fetuses with CDH at birth are contradictory. The lack of a chronological study of surfactant content in late pregnancy has been a significant limitation. The appropriateness of administering surfactant supplements to neonates with CDH is therefore a debated question.

METHODS AND FINDINGS

We investigated surfactant content in human fetuses with CDH compared to age-matched fetuses with nonpulmonary diseases used as controls. Concentrations of disaturated phosphatidylcholine and surfactant proteins were found to be similar at a given stage of pregnancy, with both components showing a similar pattern of increase with progressing pregnancy in fetuses with CDH and in control fetuses. Thyroid transcription factor 1, a critical regulator of surfactant protein transcription, similarly displayed no difference in abundance. Finally, we examined the expression of three glucocorticoid-regulated diffusible mediators involved in lung epithelial maturation, namely: keratinocyte growth factor (KGF), leptin, and neuregulin 1 beta 1 (NRG1-beta1). KGF expression decreased slightly with time in control fetuses, but remained unchanged in fetuses with CDH. Leptin and NRG1-beta1 similarly increased in late pregnancy in control and CDH lungs. These maturation factors were also determined in the sheep fetus with surgical diaphragmatic hernia, in which surfactant deficiency has been reported previously. In contrast to the findings in humans, surgical diaphragmatic hernia in the sheep fetus was associated with decreased KGF and neuregulin expression. Fetoscopic endoluminal tracheal occlusion performed in the sheep model to correct lung hypoplasia increased leptin expression, partially restored KGF expression, and fully restored neuregulin expression.

CONCLUSIONS

Our results indicate that CDH does not impair surfactant storage in human fetuses. CDH lungs exhibited no trend toward a decrease in contents, or a delay in developmental changes for any of the studied surfactant components and surfactant maturation factors. Surfactant amounts are likely to be appropriate to lung size. These findings therefore do not support the use of surfactant therapy for infants with CDH. Moreover, they raise the question of the relevance of CDH animal models to explore lung biochemical maturity.

Antenatal and postnatal lung and vascular anatomic and functional studies in congenital diaphragmatic hernia: implications for clinical management

Congenital diaphragmatic hernia is characterized by fetal and neonatal lung hypoplasia as well as vascular hypoplasia. Antenatal imaging studies have been performed that attempt to quantify the degree of hypoplasia and its impact on infant prognosis. Prenatal and perinatal growth of the lung and vasculature are interdependent and their continued coordinated growth is critical for survival after birth in this patient population. Lung protection strategies appear to improve survival in newborns with diaphragmatic hernia, but a subset of infants remain who demonstrate sufficiently severe lung hypoplasia that we are unable to provide support long-term after birth. Fetal intervention is a strategy designed to enhance fetal lung growth towards improving survival in this most severely affected group, though other therapies to enhance postnatal lung and vascular growth should be concurrently investigated. However, any of these interventions will require careful selection of those infants at risk for poor outcome and thorough follow up, since long-term morbidity is significant in children with diaphragmatic hernia.

Prenatal intervention for congenital diaphragmatic hernia

Advances in prenatal ultrasound have revealed the poor natural history of fetal congenital diaphragmatic hernia (CDH) and its hidden mortality during gestation and immediately after birth. Attempts to improve this poor outcome led to the development of prenatal surgical intervention for severe CDH by Harrison and his colleagues at the University of California San Francisco. Prenatal surgical intervention for CDH has seen four phases: open fetal surgical repair, open surgical tracheal occlusion, endoscopic external tracheal occlusion, and endoscopic endoluminal tracheal occlusion. After extensive work in the laboratory, prenatal intervention has been applied in humans since 1984. With the most recent techniques, maternal risk is significantly reduced as is the incidence of preterm labor. In the meantime, the survival rate of fetuses with CDH without fetal intervention has improved mainly due to the minimization of iatrogenic lung injury by gentle ventilation, first described in 1985. However, the morbidity of the survivors with severe CDH remains high. Prenatal intervention for CDH will be justified if improvement in survival or morbidity can be demonstrated when compared to planned delivery and postnatal management with gentle ventilation strategy.