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Objective: To examine the association between prenatal magnetic resonance imaging (MRI) based observed/expected total lung volume (O/E TLV) and outcome in neonates with giant omphalocele (GO)., Methods: Between 06/2004 and 12/2019, 67 cases with isolated GO underwent prenatal and postnatal care at our institution. MRI-based O/E TLVs were calculated based on normative data from Meyers and from Rypens and correlated with postnatal survival and morbidities. O/E TLV scores were grouped based on severity into <25% (severe), between 25% and 50% (moderate), and >50% (mild) for risk stratification., Results: O/E TLV was calculated for all patients according to Meyers nomograms and for 49 patients according to Rypens nomograms. Survival for GO neonates with severe, moderate, and mild pulmonary hypoplasia based on Meyers O/E TLV categories was 60%, 92%, and 96%, respectively (p = 0.04). There was a significant inverse association between Meyers O/E TLV and risk of neonatal morbidities (p < 0.05). A similar trend was observed with Rypens O/E TLV, but associations were less often significant likely related to the smaller sample size., Conclusion: Neonatal outcomes are related to fetal lung size in isolated GO. Assessment of Meyers O/E TLV allows identification of GO fetuses at greatest risk for complications secondary to pulmonary hypoplasia., (© 2021 John Wiley & Sons Ltd.)

Background: Congenital pulmonary airway malformations (CPAM), bronchopulmonary sequestrations (BPS), and CPAM-BPS hybrid lesions are most commonly solitary; however, >1 lung congenital lung lesion may occur., Objectives: To assess the frequency of multiple congenital thoracic anomalies at a high-volume referral center; determine prenatal ultrasound (US) and magnetic resonance imaging (MRI) features of these multifocal congenital lung lesions that may allow prenatal detection; and determine the most common distribution or site of origin., Methods: Database searches were performed from August 2008 to May 2019 for prenatally evaluated cases that had a final postnatal surgical diagnosis of >1 congenital lung lesion or a lung lesion associated with foregut duplication cyst (FDC). Lesion location, size, echotexture, and signal characteristics were assessed on prenatal imaging and correlated with postnatal computed tomographic angiography and surgical pathology. -Results: Of 539 neonates that underwent surgery for a thoracic lesion, 35 (6.5%) had >1 thoracic abnormality. Multiple discrete lung lesions were present in 19 cases, and a lung lesion associated with an FDC was present in 16. Multifocal lung lesions were bilateral in 3 cases; unilateral, multilobar in 12; and, unilobar multisegmental in 4. Median total CPAM volume/head circumference ratio for multifocal lung lesions on US was 0.66 (range, 0.16-1.80). Prenatal recognition of multifocal lung lesions occurred in 7/19 cases (36.8%). Lesion combinations were CPAM-CPAM in 10 cases, CPAM-BPS in 5, CPAM-hybrid in 2, hybrid-hybrid in 1, and hybrid-BPS in 1. Of 5 unilateral, multifocal lung lesions, multifocality was prenatally established through identification of a band of normal intervening lung or intrinsic differences in lesion imaging features., Conclusions: Although less common, multiple thoracic abnormalities can be detected prenatally. Of multifocal lung lesions, the most common combination was CPAM-CPAM, with a unilateral, multilobar distribution. Prenatal recognition is important for pregnancy counseling and postnatal surgical management., (© 2020 S. Karger AG, Basel.)

Aim: To describe perinatal outcomes of fetuses with a prenatal diagnosis of a concomitant lung lesion in the setting of congenital diaphragmatic hernia (CDH) and to compare outcomes with an isolated CDH control group without a lung lesion, matched by ultrasound-based prognostic markers including presence of liver herniation and lung measurements., Material and Methods: This was a retrospective case-control study, wherein all pregnancies diagnosed with CDH and concomitant lung lesions were identified between July 1, 2008, and December 31, 2018. For each case, 2 controls with isolated CDH from the same study period were selected after matching for the presence of liver herniation into the thoracic cavity and ultrasound-based lung measurements either observed over expected lung-to-head ratio (LHR) or absolute LHR with their corresponding gestational age. The outcomes analyzed in the 2 groups included survival to hospital discharge, neonatal intensive care unit (NICU) length of stay (LOS), extracorporeal membrane oxygenation (ECMO) requirement and need for supplemental oxygen (O2) at day 30 of life., Results: A total of 21 pregnancies were identified with CDH and a concomitant lung lesion in the study period. All the lung lesions were stratified into a "low-risk category" with a congenital cystic adenomatoid malformation volume ratio of less than 1.0 at the time of presentation. None of these fetuses developed hydrops or required in utero intervention. Overall survival in the group was 80.7% (17/21) and rate of ECMO was 38.1%. Causes of mortality included pulmonary insufficiency, sepsis, renal failure, and bowel infarction. Upon comparison between the cases and controls, the 2 groups were similar with respect to pregnancy demographics. There were no fetal demises in either group. Outcomes including survival rate, NICU LOS, ECMO requirements and need for supplemental O2 at day 30 of life, were comparable among the 2 groups., Conclusions: In our descriptive series, the presence of a concomitant, low-risk lung lesion in the setting of fetal CDH did not have a significant impact on the natural course of the disease, nor was it associated with a worse prognosis., (© 2020 S. Karger AG, Basel.)

Background: At fetal MR, congenital lung lesions are usually T2 hyperintense with respect to normal lung parenchyma. Some lesions, however, demonstrate unusual patterns of T2 hypointensity, sometimes in a rosette-like pattern. These lesions usually present a diagnostic conundrum., Objective: To evaluate the imaging findings and pathological characterization of fetal solid lung lesions with elements showing T2-hypointense signal with respect to lung., Materials and Methods: This is a retrospective study of lung lesions with elements showing T2 hypointensity treated prenatally and postnatally at our center and with available pathological evaluation. Prenatal imaging evaluation included US and MR; postnatal evaluation consisted of pathological examination of the lesion. We also performed prenatal and postnatal chart review., Results: Six cases met study criteria. Areas of decreased echogenicity/T2-hypointense signal were more conspicuous at MR than US. At pathology, these areas correlated with immature parenchymal development and increased mesenchymal tissue. Five of these lesions were congenital pulmonary airway malformations (CPAM); one was a congenital peribronchial myofibroblastic tumor (CPMT). The lesions did not significantly change in size after steroid administration. They were all large in volume and were associated with increased amniotic fluid. All cases of CPAM underwent premature delivery (one of them weeks after fetal surgical resection of the lesion for worsening hydrops); the fetus with CPMT was delivered at term. The neonate with CPMT succumbed shortly after birth secondary to lung hypoplasia; the remaining five neonates survived., Conclusion: The differential diagnoses of prenatal lung lesions that contain unusual T2-hypointense elements include CPAM and CPMT. The T2-hypointense areas appear to correlate with increasing degree of immaturity at histology. None of the lesions significantly changed in size after prenatal administration of steroids. All cases with CPAM lesions did well despite persistent polyhydramnios and premature birth. The single case of CPMT, however, resulted in neonatal demise shortly after birth secondary to pulmonary hypoplasia. It is important that fetal radiologists, obstetricians and fetal surgeons alike are aware of these lesions so that appropriate diagnosing and parental counseling can be reached.

Background: This study sought to evaluate neurodevelopmental outcome in survivors of high-risk congenital lung lesions (CLLs) who underwent prenatal intervention or postnatal surgery within the first month of life., Methods: Forty-five high-risk CLL survivors underwent assessment using the Bayley Scales of Infant Development, 3rd Edition between July 2004 and December 2016. Scores were grouped as average, at-risk, and delayed based on SD intervals. Correlations between outcome and risk factors were analyzed by Fisher's exact test or two-sided t test as appropriate, with significant p values <0.05., Results: Open prenatal intervention was required in 13 (28.9%) children (fetal surgical resection, n = 4 , ex utero intrapartum treatment, n = 9), whereas 32 (71.1%) children had respiratory distress postnatally and required resection within the first month of life. Mean age at follow-up was 19.3 ± 10.3 months. Mean composite scores were within the expected average range. A total of 62.2% scored within the average range for all domains. At-risk scores were found in 26.7% of children in at least one domain, and 11.1% had delays in at least one domain. Neurodevelopmental outcome was similar between treatment groups. Prolonged ventilator support and neonatal intensive care unit stay, need for supplemental oxygen at day of life 30, gastroesophageal reflux disease, and delayed enteral feeding were associated with neurologic delays (all p < 0.05)., Conclusions: Neurodevelopmental scores for high-risk CLL survivors in infancy and toddlerhood are age appropriate. Neither fetal intervention nor the need for postnatal resection within the first month of life increases the risk of delays. Surrogate markers of a complicated neonatal course are predictive of adverse outcome., (Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Rationale: Disruption of normal pulmonary development is a leading cause of morbidity and mortality in infants. Congenital lung malformations are a unique model to study the molecular pathogenesis of isolated structural birth defects, as they are often surgically resected., Objectives: To provide insight into the molecular pathogenesis of congenital lung malformations through analysis of cell-type and gene expression changes in these lesions., Methods: Clinical data, and lung tissue for DNA, RNA, and histology, were obtained from 58 infants undergoing surgical resection of a congenital lung lesion. Transcriptome-wide gene expression analysis was performed on paired affected and unaffected samples from a subset of infants (n = 14). A three-dimensional organoid culture model was used to assess isolated congenital lung malformation epithelium (n = 3)., Measurements and Main Results: Congenital lung lesions express higher levels of airway epithelial related genes, and dysregulated expression of genes related to the Ras and PI3K-AKT-mTOR (phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin) signaling pathways. Immunofluorescence confirmed differentiated airway epithelial cell types throughout all major subtypes of congenital lung lesions, and three-dimensional cell culture demonstrated a cell-autonomous defect in the epithelium of these lesions., Conclusions: This study provides the first comprehensive analysis of the congenital lung malformation transcriptome and suggests that disruptions in Ras or PI3K-AKT-mTOR signaling may contribute to the pathology through an epithelial cell-autonomous defect.

Objectives: To assess the ability of prenatal ultrasound (US) in identifying systemic feeding arteries in bronchopulmonary sequestrations and hybrid lesions and report the ability of US in classifying bronchopulmonary sequestrations as intralobar or extralobar., Methods: Institutional Review Board-approved radiology and clinical database searches from 2008 to 2015 were performed for prenatal lung lesions with final diagnoses of bronchopulmonary sequestrations or hybrid lesions. All patients had detailed US examinations, and most patients had ultrafast magnetic resonance imaging (MRI). Lesion location, size, and identification of systemic feeding arteries and draining veins were assessed with US., Results: The study consisted of 102 bronchopulmonary sequestrations and 86 hybrid lesions. The median maternal age was 30 years. The median gestational age was 22 weeks 5 days. Of bronchopulmonary sequestrations, 66 had surgical pathologic confirmation, and 100 had postnatal imaging. Bronchopulmonary sequestration locations were intrathoracic (n = 77), intra-abdominal (n = 19), and transdiaphragmatic (n = 6). Of hybrid lesions, 84 had surgical pathologic confirmation, and 83 had postnatal imaging. Hybrid lesion locations were intrathoracic (n = 84) and transdiaphragmatic (n = 2). Ultrasound correctly identified systemic feeding arteries in 86 of 102 bronchopulmonary sequestrations and 79 of 86 hybrid lesions. Of patients who underwent MRI, systemic feeding arteries were reported in 62 of 92 bronchopulmonary sequestrations and 56 of 81 hybrid lesions. Ultrasound identified more systemic feeding arteries than MRI in both bronchopulmonary sequestrations and hybrid lesions (P < .01). Magnetic resonance imaging identified systemic feeding arteries that US did not in only 2 cases. In cases in which both systemic feeding arteries and draining veins were identified, US could correctly predict intrathoracic lesions as intralobar or extralobar in 44 of 49 bronchopulmonary sequestrations and 68 of 73 hybrid lesions., Conclusions: Ultrasound is most accurate for systemic feeding artery detection in bronchopulmonary sequestrations and hybrid lesions and can also type the lesions as intralobar or extralobar when draining veins are evaluated., (© 2017 by the American Institute of Ultrasound in Medicine.)

Objectives: Whereas left-sided congenital diaphragmatic hernias (L-CDH) have been extensively studied and their prognostic parameters delineated, right-sided hernias (R-CDH) have not. Published results remain inconclusive. The aim of this study is to evaluate if proven prognostic indicators of postnatal survival in the fetus with L-CDH apply to the fetus with R-CDH., Methods: Retrospective single-center study of R-CDH fetuses with available prenatal studies assessed for fetal lung volume by means of ultrasound-measured observed versus expected (O/E) lung area to head circumference (LHR) and magnetic resonance-calculated O/E total lung volume (TLV) in a 12-year time period. Percentage of herniated liver volume and postnatal use of extracorporeal membrane oxygenation (ECMO) were also evaluated., Results: In a cohort of 24 patients, O/E LHR, O/E TLV, percentage of herniated liver, and postnatal use of ECMO are not prognostic indicators of survival in the fetus with R-CDH. Cut-off values of O/E LHR of ≤45 or O/E TLV ≤25, known to select a population of severe cases for the L-CDH fetus, do not appear to extrapolate to the R-CDH fetus, as survival in both R-CDH groups is 60%., Conclusion: The findings in this study suggest that L- and R-CDH appear to behave differently, and that factors that make L-CDH fatal (low O/E TLV and O/E LHR, high-volume herniated liver) may not apply to the fetus with R-CDH., (© 2017 S. Karger AG, Basel.)

Purpose: Congenital diaphragmatic hernia (CDH) is associated with high postnatal mortality because of pulmonary hypoplasia. The prognostic utility of serial lung-to-head circumference measurements as a marker of lung growth has not been described. Our objective was to examine the relationship between the rate of interval increase of LHR and postnatal survival in left-sided CDH., Methods: We retrospectively reviewed charts of all left-sided CDH patients from January 2004 to July 2014. All ultrasound studies performed at our institution (n=473) were reviewed. Categorical and continuous data were analyzed by chi-square and Mann-Whitney t-test, respectively, and slope analysis was performed by linear regression analysis (p<0.05)., Results: A total of 226 patients were studied, with 154 long-term survivors and 72 non-survivors. Established markers of CDH severity, including intrathoracic liver position and requirement for patch repair, were significantly increased in non-survivors (p<0.0001). The rate of LHR increase as measured by linear regression and slope analysis was significantly increased in long-term survivors (p=0.0175)., Conclusions: Our findings indicate that the interval increase in LHR levels over the course of gestation correlate with survival in left-sided CDH patients. Regular ultrasonographic re-evaluation of LHR throughout gestation following diagnosis of CDH may provide prognostic insight and help guide patient management., (Copyright © 2016. Published by Elsevier Inc.)

Mainstem or lobar bronchial atresia is associated with massive pulmonary hyperplasia, contralateral pulmonary hypoplasia, non-immune hydrops and a fatal fetal prognosis. Open fetal surgery currently provides a potential therapeutic option for management of a fetus with this diagnosis. We present 2 cases of open fetal surgery for bronchial atresia at the level of the mainstem and lobar bronchus. The first case involved a left pneumonectomy performed at 26 weeks' gestation. After successful intraoperative resuscitation for fetal cardiac arrest, the fetus survived until 32 weeks' gestation when preterm premature rupture of membranes prompted delivery. The neonate expired on day of life (DOL)1. The second case involved a left upper lobectomy performed at 24(3)/7 weeks' gestation. The fetus was delivered at 34(3)/7 weeks' gestation and, after a prolonged NICU course including a completion pneumonectomy and tracheostomy, was discharged home at 8 months of life. This second case is the first report of survival following open fetal surgery for central bronchial atresia. This report highlights the potential benefit of fetal lung resection for central bronchial atresia while describing the many challenges to achieve the successful management of a fetus with this condition., (© 2014 S. Karger AG, Basel.)

Congenital diaphragmatic hernia (CDH) is an anomaly that results in lung hypoplasia and pulmonary hypertension. The lungs of the CDH fetus have an abnormal architecture, with fewer bronchial branches and decreased number of arteries and veins, factors which result in pulmonary compromise postnatally. The goal of this review is to evaluate prenatal prognostic factors in the fetus with isolated left CDH, with particular emphasis on fetal MRI. These imaging indicators may be used to provide health professionals and the parents with the most accurate information about fetal prognosis., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objectives: To investigate the prognostic value of magnetic resonance-calculated fetal lung volumes (FLV) in fetuses with isolated left congenital diaphragmatic hernia (L-CDH) who receive standardized prenatal and postnatal care at a single institution., Materials and Methods: A retrospective review was undertaken to identify fetuses with isolated L-CDH between 2001 and 2010., Results: Eighty-five cases of isolated L-CDH were identified. The overall survival was 65% (55/85). Survival was 45% if there was 'liver up' (23/51) and 94% if there was 'liver down' (32/34). Univariate statistical analysis showed that 'liver up' (p=0.001), lung-to-head ratio (LHR) at diagnosis (p=0.009), observed/expected (O/E) LHR (p=0.01), total FLV (p=0.03), right LV (p=0.04), magnetic resonance imaging (MRI) observed versus expected (O/E) FLV (p=0.002), intrathoracic versus intraabdominal stomach (p=0.002), percentage of herniated liver (p=0.004), and postnatal extracorporeal membrane oxygenation use (p=0.001) are predictive of postnatal survival. Multivariate analysis of only prenatal factors showed that the most important determinants of postnatal outcome are percentage of herniated liver, presence of liver up, and MRI O/E FLV., Conclusion: Herniated intrathoracic liver expressed as 'liver up' or as percent herniated liver and MRI measurement of FLV expressed as a O/E ratio are strong prenatal indicators of postnatal survival., (© 2012 John Wiley & Sons, Ltd.)

Purpose: The purpose of this study is to present the outcome and technical details of the Ex Utero Intrapartum Treatment (EXIT) procedure performed in the management of the fetus with a giant cervical teratoma., Methods: A retrospective review of the medical records of patients undergoing the EXIT procedure between September 1995 and September 2010 was performed., Results: Eighty-seven EXIT procedures were performed. In 20% of cases (17/87), the indication was giant cervical teratoma. There were 10 females and 7 males. Polyhydramnios was present in 82%. Median gestational age at EXIT was 35 weeks (range, 30-39 weeks). Median birth weight was 2.5 kg (range, 1.7-3.7 kg). Access to the airway under placental support was established in all cases via direct laryngoscopy/bronchoscopy in 8 patients (47%) and via surgical exploration (tracheostomy or retrograde intubation) in 9 patients (53%). The mortality rate under placental support was zero. Seven patients had the tumors resected immediately after the EXIT, 6 patients had the resection later, and 4 patients died before resection. The neonatal mortality rate was 23% (4/17 patients). Patients who died had severe pulmonary hypoplasia that resulted from the upward traction by the giant cervical mass on the airway and compression of the lungs against the thoracic apex., Conclusions: We conclude that the EXIT procedure continues to be the optimal delivery strategy for patients with prenatally diagnosed giant cervical teratomas and potential airway obstruction at birth. A thorough evaluation of the prenatal images and an experienced multidisciplinary team are key factors for an effective approach to the obstructed fetal airway., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: To determine the value of fetal MRI-calculated total lung volumes (TLV) in the prediction of short-term outcome in patients with giant omphalocele (GO)., Material and Methods: We reviewed all cases of GO undergoing fetal MRI after 21 weeks' gestation and receiving postnatal care at our institution between 2003 and 2010. Observed/expected (O/E) TLV was calculated using age-matched TLV normograms [Radiology 2001;219:236-241]. Postnatal outcomes were stratified based on O/E TLV above or below 50% of expected., Results: Seventeen GO cases fulfilled the entry criteria. The mean age at fetal MRI evaluation was 25.8 ± 4.8 weeks' gestation. The mean GO TLV (21.0 ± 13.2) was lower than age-matched population norms (p < 0.001), resulting in a mean O/E TLV of 52.3 ± 16.8%. The mean gestational age at delivery was 36.8 ± 1.6 weeks. Overall survival was 94%. Fourteen (88%) infants underwent staged reduction, and 2 underwent silver sulfadiazine treatment and delayed repair. Infants with ≤50% of predicted O/E TLV (n = 11, 65%) had lower Apgar scores at birth (p = 0.03), prolonged ventilatory support (p = 0.004), delayed oral intake (p = 0.03), and longer hospitalization (p = 0.03) compared to patients with ≥50% of expected O/E TLV. Two infants (both O/E TLV <50%) required tracheostomy placement., Conclusion: In the assessment of GO fetuses, MRI-based O/E TLV of <50% was predictive of increased postnatal morbidity., (Copyright © 2012 S. Karger AG, Basel.)

Background: The authors evaluated the efficacy of adding fentanyl to epidural bupivacaine in infants up to 6 months of age after a thoracotomy in a prospective, randomized, double-blind study. The primary outcome was the total amount of rescue doses of intravenous nalbuphine in the first 24 h after surgery. Secondary outcomes included (1) time to first rescue dose of nalbuphine, (2) pain scores, and (3) behavior scores., Methods: Thirty-two infants were randomly assigned to receive an epidural infusion containing 0.1% bupivacaine (group B; n = 16) or 0.1% bupivacaine and 2 microg/ml fentanyl (group BF; n = 16). Patients were evaluated up to 24 h after surgery for pain; amount of analgesic rescues and time to first rescue; pain scores; behavior scores (five-item behavior score); and complications, including respiratory depression, oxygen requirement, vomiting, and urinary retention., Results: The two groups had similar demographics. Nalbuphine consumption (P = 0.001) and pain scores (P < 0.001) in the first 24 h were significantly decreased in group BF compared with group B. The time to first analgesic rescue was significantly longer in group BF (P = 0.005). The five-item behavior score was significantly better in group BF than in group B (P = 0.01). The incidence of side effects, the time to first successful feeding, and the time to discharge were similar in both groups., Conclusions: Addition of 2 microg/ml epidural fentanyl to 0.1% bupivacaine results in improved postthoracotomy analgesia without any increase in side effects, compared with 0.1% bupivacaine, in infants up to 6 months of age.

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

Objective: The purpose of this study was to determine the ability of liver position and lung-to-head ratio to predict outcome in isolated left congenital diaphragmatic hernia., Study Design: We reviewed prenatal studies and postnatal outcomes of congenital diaphragmatic hernia between January 1996 and January 2006., Results: Eighty-nine patients received prenatal and postnatal care at 1 institution. In fetuses with liver up, extracorporeal membrane oxygenation was required in 39 of 49 fetuses (80%), compared with 10 of 40 fetuses (25%) for those with liver down (P < .0001). Overall survival rate was 45%, compared with 93% for those with liver down (P < .00005). Low lung-to-head ratio (<1.0) predicted increased incidence of extracorporeal membrane oxygenation (75%; P = .036) and lower survival (35%; P = .0003). However, when measured at <24 weeks of gestation, lung-to-head ratio was not predictive of outcome (extracorporeal membrane oxygenation, P = .108; survival, P = .150); liver position remained highly predictive (extracorporeal membrane oxygenation, P = .006; survival, P = .001)., Conclusion: Liver position is the best prenatal predictor of outcome in isolated left congenital diaphragmatic hernia. Lung-to-head ratio alone should not be used to counsel families regarding mid gestational management choices.

In fetal sheep with surgically created diaphragmatic hernia (DH), tracheal occlusion (TO) can restore lung growth but does not ameliorate the increase in inter-alveolar wall thickness (T(W)). We determined whether prenatal exposure to glucocorticoids (GC) could reduce T(w) in fetuses with DH undergoing TO. At 65 days of gestation, DH was created in 12 fetal sheep, and TO subsequently performed at 110 days (DH/TO). Six of these fetuses were exposed to betamethasone (DH/TO + GC; 0.5 mg/kg; maternal, IM) 48 hr before delivery; Sham operated fetuses (n = 7) served as controls. At 139 days, we measured alveolar surface density (S(V)), parenchymal tissue fraction, T(W), alveolar type 2 (AE2) cell density and lung surfactant protein (SP) mRNA expression. Prenatal GC decreased T(W) and S(V) by 33% and 27% respectively, and increased fixed lung volume (by 55%), AE2 cell density and partially restored SPmRNA expression. Our data indicate that prenatal exposure to GC can reverse some of the negative effects of prolonged fetal TO. We hypothesize that a GC-induced reduction in lung liquid volume during TO contributes, in part, to the observed increase in AE2 cell density and SPmRNA expression.

Background: Indications for the ex utero intrapartum therapy (EXIT) procedure have expanded to include any fetal anomaly in which resuscitation of the neonate may be compromised., Methods: We reviewed the medical records of 9 patients after resection of lung lesions during the EXIT procedure., Results: The mean gestational age at EXIT procedure was 35.4 weeks. All lung masses maintained large sizes late into gestation with mean mass volume/head circumference ratio of 2.5 at presentation and 2.2 at EXIT. Seven of 9 fetuses demonstrated hydropic changes (n = 6) and/or polyhydramnios (n = 5), and underwent prenatal intervention including thoracentesis, thoracoamniotic shunt placement, amnioreduction, and/or betamethasone administration. Overall survival after EXIT for lung mass resection was 89%. The average time on placental bypass was 65 minutes. Postnatal complications included reoperation for air leak (n = 1), reoperation for bleeding (n = 1), and death from sepsis and prematurity (n = 1). Venoarterial extracorporeal membrane oxygenation was used in 4 neonates for persistent pulmonary hypertension. Maternal prenatal complications included polyhydramnios (n = 5), preterm labor (n = 4), and chorioamnionitis (n = 1). One mother required perioperative blood transfusion., Conclusion: The EXIT procedure allows for controlled resection of large fetal lung lesions at delivery, avoiding acute respiratory decompensation related to mediastinal shift, air trapping, and compression of normal lung.

Objective: Although the mechanisms responsible for lung growth following tracheal occlusion (TO) are not fully understood, lung fluid accumulation is a requirement for growth to occur. It is known that betamimetics such as epinephrine (Epi), terbutaline, and ritodrine inhibit fetal lung fluid production late in gestation. We hypothesized that continuous infusion of Epi would have a detrimental effect on lung growth following TO in the fetal sheep model., Methods: Twenty fetal lambs were divided into four groups. Group 1: no TO without Epi (n = 4); group 2: TO without Epi (n = 4); group 3: no TO with Epi (n = 5), and group 4: TO with Epi (n = 7). TO was performed on days 130-134 of gestation (full term = 145 days). In groups 3 and 4, Epi was infused into the fetus at a rate of 2 microg/min using a miniosmotic pump implanted subcutaneously at the time of TO. The fetuses were sacrificed after 4 days, and lung volume (LV, ml/kg), drained lung fluid (LF, ml/kg), wet lung weight/body weight ratio (LW/BW, %), whole right-lung dry weight per body weight ratio (dRLW/BW, g/kg), volume density of lung parenchyma (v(Vp)), and right-lung DNA and protein contents were compared among the four groups by one-way Anova., Results: LW/BW and dRLW/BW of group 4 (3.91 +/- 0.52 and 2.10 +/- 0.28, mean +/- SD) were significantly lower than those of group 2 (5.18 +/- 0.57 and 2.67 +/- 0.15) and were not statistically significantly different from those of group 1 or 3. LV, LF, V(Vp), and DNA and protein contents all showed a similar trend., Conclusions: Continuous infusion of Epi to the fetus results in less fluid accumulation within the TO lungs and abolishes significant lung growth after TO in the late-gestation fetal lamb. Drugs affecting lung fluid secretion may have a major impact on TO-induced lung growth., (Copyright 2003 S. Karger AG, Basel)

Background/purpose: Initial laboratory and clinical data suggest that partial liquid ventilation (PLV) can enhance pulmonary function and that lung growth can be induced via distension of the newborn lung using perfluorocarbon in patients with congenital diaphragmatic hernia (CDH). The authors, therefore, performed a prospective, randomized pilot study evaluating PLV and perfluorocarbon-induced lung growth (PILG) in newborns with CDH on extracorporeal life support (ECLS) at 6 medical centers., Methods: Patients were selected randomly using a permuted block design to PLV/PILG (n = 8) or conventional mechanical ventilation (CMV/control, n = 5). Patients in the PILG group received daily doses which filled the lungs with perflubron for up to 7 days and were placed on continuous positive airway pressure of 5 to 8 cm H2O. CMV patients were treated with standard mechanical ventilation while on extracorporeal membrane oxygenation (ECMO)., Results: A total of 13 patients were evaluated in this study. All 3 patients enrolled without being on ECLS rapidly transitioned to ECLS. The study, therefore, effectively evaluated PILG (n = 8) versus standard ventilation (control, n = 5) on ECLS. Mean (+/- SE) gestational age was 37 +/- 1 weeks and weight was 3.1 +/- 0.1 kg. Time on ECMO was 9.8 +/- 2.3 days in the PILG and 14.5 +/- 3.5 days (P =.58) in the control group. Survival rate in the PILG group was 6 of 8 (75%), whereas survival rate was 2 of 5 (40%) in the control group (P =.50). The number of days free from the ventilator in the first 28 days (VFD) was 6.3 +/- 3.3 days with PILG and 4.6 +/- 4.6 days with control (P =.9). Causes of death in the PILG group included sepsis and renal failure in one patient and pulmonary hypertension in the other. There were no safety issues, and the deaths in the PILG group did not appear to be related to the administration of perflubron., Conclusions: These data show that PILG can be performed safely. The survival rate, VFD, and time on ECMO data, although not conclusive, are encouraging and indicate the need for a definitive trial of this novel intervention in these neonates with high mortality., (Copyright 2003, Elsevier Science (USA). All rights reserved.)

Prolonged fetal tracheal occlusion (TO) accelerates lung growth but leads to loss of alveolar epithelial type II (AE2) cells. In contrast, temporary TO leads to recovery of AE2 cells and their ability to produce surfactant. The aim of this study was to determine the effects of temporary TO in fetal sheep with lung hypoplasia on postnatal lung function, structure, and surfactant protein mRNA expression. Diaphragmatic hernia (DH) was created in 22 fetal sheep at 65 days of gestation. TO was performed between 110 days of gestation and full term (DH/TO, n = 7) and between 110 and 130 days of gestation (DH/TO+R, n = 6). Sham-operated fetuses (n = 11) served as controls. Lambs were delivered at approximately 139 days of gestation, and blood gas tensions were monitored over a 2-h resuscitation period. Temporary TO increased growth of the hypoplastic lung and restored surfactant protein mRNA expression and AE2 cell density but did not improve respiratory function above that of animals that underwent prolonged TO; DH/TO and DH/TO+R lambs were hypoxic and hypercapnic compared with Sham animals. Lung compliance remained low in DH/TO+R lambs, most likely as a consequence of the persistent increase in alveolar wall thickness in these animals.

The aim of this study was to determine the accuracy of a new computer-assisted stereological technique in obtaining structural information of the lung. We compared the point fraction of lung parenchyma (Pp) and alveolar surface density (Sv) obtained by established manual point/intercept counting methods and compared them with those obtained using a computer-assisted method. Lung tissues obtained from normally grown fetal sheep (n = 6) and from newborn lambs with severe lung hypoplasia (n = 5) were inflation fixed via the trachea and processed for light microscopy. In verification-of-technique experiments, Pp and Sv correlated well with known values. There was a significant linear correlation between manual and computer-assisted stereological measurements for values of Pp (r2 = 0.92) and Sv (r2 = 0.98). Our data lead us to believe that the computer-assisted stereological technique described in this study provides accurate estimates of Pp and Sv and hence may be a valuable tool for evaluating the effects of factors upon structural development of the lung.

We examined the effect of accelerated lung growth, induced by in utero tracheal occlusion (TO), on lung liquid uptake in near-term fetal sheep. In utero TO was performed in five fetal sheep at 110 days of gestation (term, approximately 145 days); six SHAM operated fetuses served as controls. The rate of liquid movement across the pulmonary epithelium was measured, using a previously established technique, in anesthetized fetal sheep between 133-137 days of gestation during a 2-hr adrenaline infusion (0.50 microg/min/kg, I.V.) and while lung luminal pressure was maintained at 5 mmHg. The rate of fetal lung liquid uptake was linear in all fetuses (mean r(2) < 0.97, n = 11). Mean values of lung liquid uptake expressed in relation to dry lung weight and luminal surface area of the right lung were significantly lower in TO fetuses (1.8 +/- 0.3 mL/hr/g and 1.0 +/- 0.2 mL/hr/m(2)) than in SHAM fetuses (2.6 +/- 0.2 mL/hr/g and 1.8 +/- 0.1 mL/hr/m(2)); surface area of the right lung was 140% greater in TO fetuses than in SHAM fetuses. There was a linear relationship between lung liquid uptake and pulmonary epithelial surface area in SHAM animals, but not in TO fetuses. We hypothesize that loss of alveolar epithelial type-II cells induced by increased levels of fetal lung expansion may impair alveolar liquid clearance in the perinatal period., (Copyright 2002 Wiley-Liss, Inc.)

Background/purpose: Prenatal tracheal occlusion (TO) has been shown to accelerate lung growth in animal models and models of pulmonary hypoplasia. However, these models may not mimic early events in human congenital diaphragmatic hernia (CDH). The authors previously have developed a model of TO in the rat. The purpose of this study was to apply this technique to characterize TO-induced lung growth in the early onset nitrofen-induced model of CDH, and to address the clinically important questions of the effect of timing of TO and maternal infusion of terbutaline on TO-induced lung growth., Methods: Left-sided CDH was induced in the fetuses of time-dated pregnant Sprague-Dawley rats by feeding 100 mg of nitrofen on day 9 of gestation. TO was performed via maternal laparotomy and hysterotomy at 19 days' gestation. At harvest (21.5 days' gestation), lungs from nitrofen-exposed fetuses without CDH (non-CDH), with CDH (CDH), and with CDH and TO (CDH-TO) were compared by analysis of wet and dry weight, DNA and protein content, and stereologic morphometry. A second study was performed to assess relative lung growth achieved by equal intervals of TO after "early" (19 days) versus "late" (20 days) gestational TO. Finally, the effect of maternal infusion of terbutaline, a commonly used tocolytic for fetal surgery, on TO-induced lung growth was analyzed., Results: Analysis of lung growth showed consistent and significant lung growth in CDH-TO lungs. Lung growth after TO was proliferative and characterized by an increase in parenchymal volume as manifest by increased total saccular number and surface area and radial saccular count. Although visceral reduction was partially achieved, herniated liver was reduced incompletely. The majority of lung growth occurred during the latter half of the TO period. Early gestational age at TO and maternal terbutaline administration adversely influenced lung growth in CDH-TO fetuses., Conclusions: Prenatal TO induces dramatic lung growth in the early onset, nitrofen-induced rat model of CDH. TO is more effective later in gestation presumably because of the advanced stage of lung development and lung fluid production. This effect could be counterbalanced by the use of beta-mimetic tocolytic, which inhibits fetal lung fluid production late in gestation. Multiple factors including fetal lung fluid production and absorption, pharmacologic agents, space-occupying herniated viscera, and timing and duration of TO may be important clinical variables. The development of the rat model should facilitate further studies into the cellular and molecular mechanisms responsible for TO-induced lung growth.

Objective: We evaluated the use of fetal magnetic resonance imaging in predicting outcomes after ultrasonographic diagnosis of left-sided congenital diaphragmatic hernia., Study Design: Forty-one pregnant women carrying fetuses with congenital diaphragmatic hernia underwent 43 magnetic resonance imaging scans. Lung volumes were calculated by summing the areas on 6-mm axial sections. The presence or absence of liver herniation was noted. A liver/diaphragm ratio was obtained by using the distances from the superior aspect of the liver and the diaphragmatic remnant to the apex of the chest., Results: Mean gestational age was 26 weeks and overall survival was 59%. Neither right, left, nor total lung volume measurements were predictive of survival. Liver herniation into the left side of the chest was predictive of outcome at P<.05. The liver/diaphragm ratio was predictive of outcome at P = .03., Conclusion: Fetal magnetic resonance imaging permits calculation of lung volumes, but these volumes are not predictive of outcome. However, both the presence of liver herniation and the volume of liver within the chest, as reflected by the liver/diaphragm ratio, help predict outcome in left-sided congenital diaphragmatic hernia.

Background/purpose: Prenatal tracheal occlusion (TO) has been shown to accelerate lung growth, yet the mechanism for this effect is poorly understood. Increased intratracheal pressure (ITP) with accumulation of lung fluid and secondary airway distension (stretch) may provide a mechanical stimulus for growth. In this study, ITP after TO is measured continuously, and the effect of altering ITP on lung growth is examined., Methods: Fetal lambs of 115 to 120 days of gestation (term, 145 days) underwent placement of an intratracheal catheter and an amniotic fluid reference catheter. First, ITP was monitored continuously in normal controls (n = 4) and in fetuses undergoing TO (n = 6). In a subsequent study, 2 groups of fetuses were compared. In the TO group (n = 5) ITP was monitored after TO. In the pressurized group (n = 5) ITP was maintained at 7 to 8 mm Hg by a continuous servo regulated pump that maintains a preset pressure by lactated Ringers infusion. The animals were killed after 4 days, and lung growth was compared., Results: In the control animals, ITP remained constant at 0.4 to 1.5 mm Hg. In the TO animals, ITP increased gradually during the initial 24 hours and plateaued at 4 to 5 mm Hg. In the second set of animals, ITP in the pressurized group was maintained at approximately 8 mm Hg using the infusion system. Lung volume (135.7+/-17.4 v. 95.2+/-14.8 mL/kg; P<.01), lung weight to body weight (6.70+/-0.73 v. 5.33+/-0.77%; P<.05), whole right lung dry weight (3.10+/-0.22 v. 2.63+/-0.20 mg/kg; P<.05), and right lung DNA and protein contents (87.3+/-6.0 v. 74.6+/-8.1 mg/kg, 2,310+/-248 v. 1,860+/-196 mg/kg, respectively; P<.05) were increased significantly in the pressurized group compared with the TO group. Morphometry confirmed greater volume of respiratory region and increased alveolar surface area in the pressurized lung., Conclusions: TO results in a gradual increase in ITP over 15 to 24 hours, which plateaus at 4 to 5 mm Hg. Further increasing ITP by infusion of crystalloid significantly augments lung growth beyond that observed with TO alone. These data support the hypothesis that airway pressure and secondary mechanical stretch are the primary stimuli of TO induced lung growth.

Background/purpose: Physiological changes secondary to a rapidly enlarging fetal chest mass can lead to nonimmune hydrops, which is a predictor of impending fetal demise. Currently, open fetal surgery is offered for specific patients with hydrops before 32 weeks' gestation. The authors asked if a less-invasive technique, radiofrequency thermal ablation (RTA), could be applied safely to the destruction of fetal lung tissue., Methods: Time-dated pregnant ewes at 120 to 125 days' gestation (term, 140 to 145 days) underwent RTA through a hysterotomy (n = 3) or in a transuterine fashion under ultrasound guidance (n = 4). The probe is a 15-gauge needle with a maximal 2-cm deployment sphere at its tip. By varying the intensity and duration of treatment, the power settings were optimized to create a defined area of ablation with minimal surrounding tissue injury. Five of the 6 fetal lambs were killed acutely, and 1 was followed up for 1 week with frequent ultrasound examinations., Results: Gross examination of the animals killed acutely showed a consistent area of ablation using 10 watts of applied power for 3 minutes. Direct coagulation necrosis lesions ranged from 1x1 cm to 2x2 cm in size depending on the extent of the probe deployment. One animal was followed up for 1 week and showed no major adverse physiological effects., Conclusion: Radiofrequency thermal ablation can be performed safely in this fetal sheep model to create a controlled area of lung tissue ablation.

Background: During lung development, platelet-derived growth factor-BB (PDGF-BB) is maximal during the canalicular stage and decreases by the saccular stage. PDGF-BB stimulates lung growth by increasing cell proliferation. Fetal CCAMs have been shown to have an elevated proliferative index, but it is not known why some CCAMs rapidly enlarge in utero and cause fetal hydrops. The authors hypothesized that the high proliferative index and rapid enlargement of some fetal CCAMs may be caused by persistently elevated PDGF-BB production compared with normal fetal lung., Methods: To test this hypothesis, tissue was obtained at the time of resection from two fetal CCAMs (22 weeks), three full-term CCAMs, and three normal fetal lungs (21 to 22 weeks). PDGF-BB production by fetal CCAMs was compared with normal age-matched fetal lung using immunohistochemistry, reverse transcriptionase-polymerase chain reaction (RT-PCR), and Western blot analysis., Results: CCAMs resulting in fetal hydrops and requiring fetal resection had strong mesenchymal immunostaining for PDGF-BB next to epithelial lined cysts, increased PDGF-B gene expression by RT-PCR, and elevated PDGF-BB protein by Western blot, compared with normal age-matched fetal lung. Term CCAMs had minimal PDGF-BB staining, PDGF-B gene expression, and PDGF-BB protein production., Conclusions: CCAMs that grew rapidly and progressed to hydrops, requiring in utero resection, demonstrated increased mesenchymal PDGF-B gene expression and PDGF-BB protein production compared with age-matched normal fetal lung, which may, in part, be responsible for the autonomous growth and proliferation seen in hydropic fetal CCAMs.

Background/purpose: Advancements in gene transfer technology and prenatal diagnosis have allowed investigators to consider an in utero gene therapy approach for fatal genetic diseases. The authors sought to develop fetoscopic techniques for gene delivery and investigate the efficacy and safety of recombinant adenoviral vectors in the fetus., Methods: Fetal sheep between 60 and 130 days' gestation (dGA) underwent either fetoscopic intratracheal injection or umbilical vein (UV) injection of recombinant adenovirus, AdCMVlacZ. At death, fetal organs were examined for beta-galactosidase expression, histopathology, and CD45 immunostaining. Fetal serum was compared with preimmune serum for transaminase levels and the presence of antiadenoviral neutralizing antibodies., Results: Fetoscopic intratracheal delivery of AdCMVlacZ in late-gestation sheep fetuses resulted in efficient alveolar gene transfer, but, antiadenoviral immunologic reactions limited the longevity of transgene expression to 14 days. This prompted an examination of whether early gestational exposure could induce tolerance in the fetus to adenoviral and transgene antigens. AdCMVlacZ (1 x 10(11) particles) was injected via UV into fetuses at 60 dGA. Within 3 days, beta-galactosidase expression was localized to the fetal liver, adrenal glands, kidneys, and endocardium. Although adrenal expression was nearly constant over 28 days, expression in fetal liver disappeared within 14 to 28 days. Loss of hepatic expression did not appear to be immune mediated because there was no evidence of hepatic inflammation or appearance of antiadenoviral neutralizing antibodies. Fetuses injected with AdCMVlacZ at 60 dGA were reinjected with 1 x 10(13) particles at 125 dGA and antiadenoviral humoral immune responses were recorded. Despite early-gestation adenovirus injection, fetuses still responded to the late-gestation adenoviral exposure, developing antiadenoviral neutralizing antibodies similar to control fetuses., Conclusions: The authors developed fetoscopic access for pulmonary adenovirus delivery in late-gestation sheep. Although initial alveolar transduction was highly efficient, antiadenoviral immune responses limited the duration of transgene expression. In contrast, early-gestation adenoviral delivery did not elicit antiadenoviral immune responses despite achieving efficient transduction of many fetal tissues. Furthermore, early-gestation adenovirus delivery did not affect late-gestation antiadenoviral immune responses. These findings suggest that the early-gestation sheep fetus is not amenable to adenoviral tolerance induction by UV injection and that it is incompetent of immunologic response to adenovirus. For the purposes of in utero gene therapy, recombinant adenovirus may be applied optimally to genetic diseases requiring transient in utero expression.

Background: Prenatal tracheal occlusion accelerates fetal lung growth, but the mechanism of this phenomenon is unknown. Previous animal models have been limited by expense, lack of species-specific molecular probes, or the stage of lung development when studies could be performed. To provide a model that is more amenable to systematic analysis, we have developed an in vivo rat model of prenatal tracheal occlusion., Methods: Time-dated pregnant rats underwent laparotomy at 19 days' gestational age (term, 22 days). The fetal head and neck were exteriorized through a hysterotomy, and the trachea was ligated under a dissecting microscope. The fetus was returned to the amniotic cavity, and the uterine and maternal abdominal incisions were closed. The dam and the fetuses were killed at 21.5 days' gestational age, and the fetal lungs were assessed for lung growth and compared with nonoperated littermate controls., Results: Thirty-two of 50 manipulated fetuses survived. Of the 32 survivors, successful tracheal ligation was confirmed in 20, and these 20 fetuses were compared with 33 littermate controls. Fetal body weight (4.81+/-0.26 g v 4.87+/-0.41 g) and heart weight (0.05+/-0.01 g v 0.05+/-0.01 g) were not significantly different between ligated fetuses and littermate controls, whereas the wet lung weight (0.30+/-0.06 g v 0.13+/-0.02 g, P<.01), lung-to-body-weight ratio (6.34+/-1.16% v 2.64+/-0.41%, P<.01), dry lung weight (17.4+/-2.45 mg v 12.1+/-1.87 mg, P<.01), total lung DNA (1210+/-371 microg v 828+/-208 microg, P<.01), and total lung protein (14.3+/-5.3 mg v 8.7+/-1.7 mg, P<.01) were increased significantly in the ligated fetuses. The enlarged lung demonstrated normal histology findings after inflation fixation., Conclusions: Prenatal tracheal occlusion during the canalicular stage of lung development accelerates lung growth in the rat. In comparison with other large animal models, this relatively inexpensive small animal model has the distinct advantages of a short gestation, a large number of fetuses per litter, the availability of a developmental model of congenital diaphragmatic hernia, and the availability of well-defined molecular probes to investigate the mechanism of tracheal occlusion-induced lung growth.

Purpose: The authors hypothesized that in utero tracheal occlusion would reverse the high impedance to pulmonary blood flow associated with congenital diaphragmatic hernia (CDH) and normalize the fetal physiological response to oxygen at term., Methods: Three experimental groups were studied. Six fetal lambs (CDH group) underwent creation of a left CDH at 80 days' gestation, an additional six fetal lambs underwent left CDH creation at 80 days' gestation followed by fetal tracheal occlusion performed at 108 days' gestation (CDH + TO group), and four control fetal lambs (control group) underwent a sham procedure at 80 days gestation. All lambs were followed up at 2-week intervals by pulse wave Doppler echocardiography. At each time-point the pulsatility index (PI) was calculated for the left branch pulmonary artery from the Doppler blood velocity waveform. Near term (term, 145 days gestation) at 136 days gestation, measurements were repeated under maternal normoxia and hyperoxia. The fetal lungs were harvested and processed for morphometric analysis by radial alveolar counts (RAC) and lung-to-body-weight ratios (LBWR) as measures of lung growth., Results: At 136 days' gestation the PI of the CDH + TO group (2.88 +/- 0.29) and control group (3.97 +/- 0.37) were significantly lower compared with the PI of the CDH group (9.02 +/- 0.50). There was a significant decrease in the PI of both the CDH + TO group and the control group with maternal hyperoxia at term, whereas the CDH group showed no change. The lungs of the CDH group fetuses were significantly smaller by LBWR and RAC than both CDH + TO and control fetuses., Conclusions: An elevated PI is associated with pulmonary hypoplasia, fetal tracheal occlusion reverses this finding, and results in a normal fetal physiological response to changes in oxygen tension at term.

Tracheal occlusion affects both fetal lung growth and maturation. The authors used a murine in vitro whole organ culture model to investigate these effects. The authors hypothesized that tracheal ligation would increase lung growth by increasing cell proliferation and would change surfactant protein synthesis in this system. Lungs were removed from day 14 gestation murine fetuses (term, 21 days). Tracheas were ligated and explants cultured in chemically defined, serum-free media for 1, 3, 4, 5, 7, or 14 days. DNA synthesis and cell division were assessed using a 5-bromo-2'-deoxy-uridine (BrdU) incorporation assay. Surfactant proteins A and B, markers of lung maturity, were detected using immunohistochemistry. Ligated lungs showed more BrdU-labeled cells per 1,000 x field (cells/hpf) at every time point. Ligated lungs on day 1 showed 27% more cells/hpf than unligated, on day 3, 21% more, on day 5, 54% more, on day 7, 60% more, and on day 14, 123% more (P < .05). In contrast, ligated lungs showed significantly less staining for surfactant proteins A and B than did unligated lungs. The authors conclude that tracheal ligation increases cell division but decreases surfactant protein in fetal murine lungs in vitro. These data suggest that although tracheal occlusion increases lung growth, it may decrease or delay lung maturation. This model provides a powerful tool for investigating the mechanisms underlying fetal lung development and tracheal occlusion-induced pulmonary hyperplasia.

Most fetuses with congenital diaphragmatic hernia (CDH) diagnosed before 24 weeks' gestation die despite optimal postnatal care. In fetuses with liver herniation into the chest, prenatal repair has not been successful. In the course of exploring the pathophysiology of CDH and its repair in fetal lambs, the authors found that obstructing the normal egress of fetal lung fluid enlarges developing fetal lungs, reduces the herniated viscera, and accelerates lung growth, resulting in improved pulmonary function after birth. They developed and tested experimentally a variety of methods to temporarily occlude the fetal trachea, allow fetal lung growth, and reverse the obstruction at birth. The authors applied this strategy of temporary tracheal occlusion in eight human fetuses with CDH and liver herniation at 25 to 28 weeks' gestation. With ongoing experimental and clinical experience, the technique of tracheal occlusion evolved from an internal plug (two patients) to an external clip (six patients), and a technique was developed for unplugging the trachea at the time of birth (Ex Utero Intrapartum Tracheoplasty [EXIT]). Two fetuses had a foam plug placed inside the trachea. The first showed dramatic lung growth in utero and survived; the second (who had a smaller plug to avoid tracheomalacia) showed no demonstrable lung growth and died at birth. Two fetuses had external spring-loaded aneurysm clips placed on the trachea; one was aborted due to tocolytic failure, and the other showed no lung growth (presumed leak) and died 3 months after birth. Four fetuses had metal clips placed on the trachea. All showed dramatic lung growth in utero, with reversal of pulmonary hypoplasia documented after birth. However, all died of nonpulmonary causes. Temporary occlusion of the fetal trachea accelerates fetal lung growth and ameliorates the often fatal pulmonary hypoplasia associated with severe CDH. Although the strategy is physiologically sound and technically feasible, complications encountered during the evolution of these techniques have limited the survival rate. Further evolution of this technique is required before it can be recommended as therapy for fetal pulmonary hypoplasia.

Fetal lungs normally produce fluid that flows through the upper airway into the amniotic fluid. In fetuses with congenital diaphragmatic hernia (CDH), obstructing the flow of lung fluid may expand the lungs and propel the viscera from the chest, alleviating the pulmonary hypoplasia associated with CDH. To test this hypothesis, left-sided diaphragmatic hernias were created in sixteen 75-day-gestation fetal lambs (full-term, 145 days). At 120 days, the trachea was ligated in eight lambs; it was left unligated in the other eight. At 135 to 140 days, the fetuses were delivered, and a tracheostomy performed. Newborns were ventilated for 1 hour and then killed. Blood gas analysis was performed at 0,5,20,40, and 60 minutes. Lung dry weight, DNA, protein, and lipid analyses, as well as plasma cortisol measurements were performed. At autopsy, in the ligated lambs, the abdominal viscera was reduced from the thorax; however, the unligated lambs had viscera completely occupying the left chest. The lungs of the ligated lambs had a higher dry weight (4.22 +/- 1.37 g/kg v 1.95 +/- 0.59 g/kg; P =.001), DNA (193.8 +/- 90.5 mg/kg v 91.5 +/- 66.4 mg/kg; P = .02), and protein (1798 +/- 691.6 mg/kg v 766.6 +/- 201 mg/kg; P = .004). Lung saturated phosphatidyl choline (SPC) levels, DNA:protein ratio, and plasma cortisol were not different between the groups. Neonatal Po2 at 60 minutes was higher in the ligated group (179.4 +/- 127.0 mm Hg v 60.9 +/- 62.4 mm Hg; P < .05), and Pco2 was lower (44.1 +/- 21.4 v 83.9 +/- 23.5; P < .05) in the ligated group.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal pulmonary hypoplasia resulting from a congenital diaphragmatic hernia (CDH) produces hemodynamic changes and morphologic abnormalities of the pulmonary vasculature. To characterize the myocardial and pulmonary vascular status of the fetus with pulmonary hypoplasia, we studied four chronically instrumented, near-term fetal lambs with pulmonary hypoplasia, induced by producing a diaphragmatic hernia. We found an elevation in the pulmonary arterial pressure (control, 43.8 +/- 5.9 mmHg; CDH, 58.8 +/- 9.1 mmHg; p < 0.05), an elevation in the systemic arterial pressure (control, 43.8 +/- 0.48 mmHg; CDH, 58.6 +/- 6.7 mmHg; p < 0.05), and an elevation in the pulmonary vascular resistance (control, 0.47 +/- 0.11; CDH, 3.87 +/- 1.9; p < 0.05). In addition, though the total pulmonary blood flow was reduced (control, 83.5 +/- 32.9 mL/min; CDH, 22.2 +/- 17.6 mL/min; p < 0.05), the blood flow reduction was proportional to the reduction in the lung mass (control, 79.8 +/- 28.1 [in flow per 100-g lung weight]; CDH, 85.4 +/- 71.7). The increase in the pulmonary vascular resistance in relation to the unit lung mass (control, 0.55 +/- 0.33; CDH, 0.99 +/- 0.5) was not as pronounced as its increase in relation to the total pulmonary blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Babies born with severe pulmonary hypoplasia are unsalvageable despite maximal therapy including extracorporeal membrane oxygenation (ECMO). Using ECMO as a bridge to transplantation, reduced-size lung grafts (pulmonary lobe or segment) could expand the pool of cadaver donors and may allow for HLA-matched living-related transplants. We tested this concept first in the piglet model and developed the technical maneuvers necessary to perform lobar and segmental lung transplants from adult pigs into neonatal piglets. Prior to clinical application, a systematic evaluation of anatomic considerations for reduced-size human lung transplantation was needed. A series of human adult and neonatal cadaver thoracic dissections were performed to determine the adult pulmonary lobe or segment with the proper size, orientation, and vascular and bronchial anatomy for use as a neonatal lung transplant. The adult right middle lobe (RML) is the best candidate for neonatal left lung replacement. The adult RML, once removed, can be rotated 180 degrees around its superior-inferior axis and the vessels and bronchus align well in the left chest of the neonate. The RML may require further reduction to fit into the neonatal left chest. Selective arterial perfusion of the RML showed the anterior segment to be a near-perfect match for fit and anatomy. This technique may eventually permit living-related lung transplantation.

Lung transplantation is now a clinical reality in adults but is limited by the scarcity of appropriate donors. The donor shortage is even more acute for neonatal and pediatric patients. Reduced-size lung grafts would expand the pool of appropriate cadaveric donors and allow HLA-matched living related lobar or segmental lung transplants. To evaluate this experimentally, we developed a model of pulmonary lobar transplantation in neonatal pigs and studied the acute hemodynamic response after transplanting the left lower lobe from a more mature donor to a neonatal recipient. Technical considerations included using the recipient atrial appendage for the pulmonary venous anastomosis. Nine pairs of pigs underwent left lateral thoracotomy. The recipient left atrial and pulmonary arterial pressures, cardiac output, and pulmonary vascular resistance were measured before pneumonectomy and after left lower lobe transplantation. Although the left atrial and pulmonary arterial pressures remained unchanged after transplantation, there was a 15% increase in pulmonary vascular resistance and a 23% reduction in cardiac output. Neither change was statistically significant. The distribution of blood flow through the left and right pulmonary arteries was unchanged after transplantation. We conclude that lobar transplantation is technically feasible in immature animals and that the pulmonary venous anastomosis to the left atrial appendage facilitates the procedure. This model may prove useful in studying lung transplantation in immature recipients and expedite implementation of reduced-size lung transplantation in neonatal and pediatric patients.

Inhibition of fetal breathing movements or increased loss of fetal lung fluid into the amniotic space have been suggested as two possible mechanisms causing pulmonary hypoplasia in the setting of oligohydramnios (OH). We examined the effect of OH produced by amniotic fluid shunting (AS) into the maternal abdominal cavity, ablation of fetal breathing by high cervical cord transection (CT), and CT and AS combined on fetal rabbit lungs at 24 days gestation. Lung growth at term (31 days) was measured by lung DNA content and wet lung weight. Compared to unoperated controls, newborns undergoing either AS alone or CT alone had much smaller lungs. When compared to CT alone, CT with AS resulted in a further significant decrease in lung growth. Thus, even when fetal breathing was eliminated by CT, AS caused further hypoplasia. If pulmonary hypoplasia in OH is related to increased loss of lung fluid, then tracheal ligation (TL) should prevent this process. TL combined with AS produced lungs with the same DNA content as controls, and thus the hypoplastic effects of OH were reversed by TL. Although fetal breathing is clearly important for lung growth, it appears that inhibition of fetal breathing is not the predominant etiology of oligohydramnios-related pulmonary hypoplasia. Fetal intrapulmonary fluid is formed by active transport across pulmonary epithelium, and may serve to distend potential airways and stimulate growth. These experiments suggest that lung hypoplasia associated with OH is related to loss of this internal stenting force.

A morphometric study was made of the remaining lung of term lambs that had undergone left pneumonectomy at 60, 80, 100, or 120 days gestation. All pneumonectomy lambs showed some compensatory growth since right lung volume to body weight ratio was higher in all lambs after pneumonectomy than in term controls. In 3 lambs operated at 80, 100, and 120 days, respectively, however, compensatory volume increase was more complete than in the other lamb of each age pair or the 2 lambs operated at 60 days. Despite individual variation, the potential for compensatory lung growth seems greater in the canalicular and later stages than in the pseudoglandular. Measurements indicating distal air-space size (volume density of alveoli, volume density of alveolar duct, surface density of alveolar epithelium, numerical density of alveoli, and mean linear intercept) were similar in all animals, but total alveolar surface area and number increased proportionally to lung volume. The fact that the remaining lung compensates by increasing alveolar number rather than by enlarging air spaces is a model of human developmental abnormalities in which the alveolar number at birth is greater than normal (polyalveolar). At the intraacinar level, a higher than normal proportion of muscularized arteries was found in lambs operated early in gestation and in lambs with smaller compensatory lung growth: an inverse relationship was seen--the lower the lung volume the higher the proportion of muscular arteries. The cause for this is unknown, but may result from the relatively increased flow to a vascular bed smaller than that of two normal lungs.

Fetal cystic adenomatoid malformation is a rare pulmonary abnormality, usually involving only a part of the lung, that is characterized by excessive growth of the terminal respiratory elements. The natural history of this lesion and hence the prognosis after antenatal detection is still unclear. We report two cases of large cystic adenomatoid malformation, diagnosed prenatally, in which the size of the mass diminished visibly during the third trimester. Both fetuses had excellent outcomes after surgery. These findings suggest that when a cystic adenomatoid malformation is diagnosed antenatally, the initial impression concerning the size of the mass and final prognosis may not necessarily predict outcome, because there may be improvement during fetal life.

We studied the natural history and pathophysiology of congenital cystic adenomatoid malformation (CCAM) detected prenatally by ultrasound in twelve fetuses. Two types of fetal CCAM can be distinguished by gross anatomy, ultrasound findings, and prognosis. Microcystic lesions are usually associated with fetal hydrops and have a poor prognosis (five cases with one survivor). Antenatal diagnosis, maternal transport, and immediate thoracotomy after birth allowed the first reported survival of a newborn with a large microcystic CCAM. Macrocystic lesions are not usually associated with hydrops and have a favorable prognosis (five of seven survived). We conclude that fetuses with hydrops are at high risk for fetal or neonatal demise without intervention. Fetuses with CCAM but without hydrops have a good chance for survival with maternal transport, planned delivery, and immediate neonatal resuscitation and surgery.