Pulmonary morbidity in 100 survivors of congenital diaphragmatic hernia monitored in a multidisciplinary clinic

The CDH Study Group and advances in the clinical care of the patient with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) occurs in 1 of every 2000 to 4000 births and accounts for 8% of all major congenital anomalies. Recurrence risk for a subsequent pregnancy is estimated at 2%. The mortality rate for CDH when diagnosed antenatally, varies with fetal age and with the presence or absence of hydramnios and degree of pulmonary hypoplasia. The prognosis has improved dramatically in recent years, primarily due to advances in neonatal and surgical interventions. Neonatal survival rates with an antenatal diagnosis now exceed 80% in some centers. Treatment for infants with CDH reflects other pediatric surgical problems in that a majority of the clinical research that shapes treatment is retrospective in nature. Because CDH is a relatively rare disease, using a compilation of cases, such as the CDH database provides, greatly aids our understanding of this disease process. Moreover, the application of a quality assessment scale provides the practitioner with a knowledge base to critically evaluate the published retrospective data.

Pulmonary elastin expression is decreased in the nitrofen-induced rat model of congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Babies with congenital diaphragmatic hernia (CDH) suffer from pulmonary hypoplasia and pulmonary hypertension. Elastin is a critical component of the extracellular matrix (EM) involved in pulmonary development and mechanics. Because CDH lungs are developmentally immature and have reduced compliance, the authors hypothesized that elastin deposition would be reduced and disorganized in the nitrofen rat model of CDH.

METHODS

Time-dated pregnant Sprague-Dawley rats were fed 100 mg of nitrofen on day 9 of gestation. Control rats did not receive nitrofen. The authors analyzed three groups of rats (n = 10 for each group): (1) control (C), (2) nitrofen no CDH (NC), and (3) nitrofen-induced CDH (CDH). On day 21.5 (term, 22 days), the fetuses were delivered by cesarean section, and the fetal lung was harvested. Elastin content, mRNA expression, and distribution were assessed with desmosine analysis, Northern blot analysis, and Hart's staining, respectively.

RESULTS

The mean desmosine content in picomole desmosine per milligram protein (pmD/mgP) +/- SD was 30 +/- 6.8 (C, n = 10), 25.1 +/- 10.1 (NC, n = 10), and 21.6 +/- 6.4 (CDH, n = 10). The comparison between CDH and controls was statistically significant (P =.026). Northern blot analysis showed decreased mRNA expression in the CDH sample. Hart's staining showed developmentally immature CDH lungs with less elastin deposition and disorganized distribution.

CONCLUSIONS

Pulmonary elastin expression is decreased and disorganized in the nitrofen-induced rat model of CDH. The decreased expression appears to be regulated at the level of transcription. Altered mechanical forces may be responsible for mediating the expression of elastin in CDH.

A randomized trial of fetal endoscopic tracheal occlusion for severe fetal congenital diaphragmatic hernia

BACKGROUND

Experimental and clinical data suggest that fetal endoscopic tracheal occlusion to induce lung growth may improve the outcome of severe congenital diaphragmatic hernia. We performed a randomized, controlled trial comparing fetal tracheal occlusion with standard postnatal care.

METHODS

Women carrying fetuses that were between 22 and 27 weeks of gestation and that had severe, left-sided congenital diaphragmatic hernia (liver herniation and a lung-to-head ratio below 1.4), with no other detectable anomalies, were randomly assigned to fetal endoscopic tracheal occlusion or standard care. The primary outcome was survival at the age of 90 days; the secondary outcomes were measures of maternal and neonatal morbidity.

RESULTS

Of 28 women who met the entry criteria, 24 agreed to randomization. Enrollment was stopped after 24 patients had been enrolled because of the unexpectedly high survival rate with standard care and the conclusion of the data safety monitoring board that further recruitment would not result in significant differences between the groups. Eight of 11 fetuses (73 percent) in the tracheal-occlusion group and 10 of 13 (77 percent) in the group that received standard care survived to 90 days of age (P=1.00). The severity of the congenital diaphragmatic hernia at randomization, as measured by the lung-to-head ratio, was inversely related to survival in both groups. Premature rupture of the membranes and preterm delivery were more common in the group receiving the intervention than in the group receiving standard care (mean [+/-SD] gestational age at delivery, 30.8+/-2.0 weeks vs. 37.0+/-1.5 weeks; P<0.001). The rates of neonatal morbidity did not differ between the groups.

CONCLUSIONS

Tracheal occlusion did not improve survival or morbidity rates in this cohort of fetuses with congenital diaphragmatic hernia.

Lung pathology in patients with congenital diaphragmatic hernia treated with fetal surgical intervention, including tracheal occlusion

Fetal intervention for congenital diaphragmatic hernia was developed to lessen the high morbidity and mortality of pulmonary hypoplasia. Lung pathology and morphometry in patients treated with fetal intervention have not been described. We report clinical and autopsy findings, as well as basic lung morphometry in 16 cases of congenital diaphragmatic hernia with fetal intervention (12 cases tracheal occlusion; 4 cases hernia repair), and 19 cases of congenital diaphragmatic hernia without fetal intervention. All patients who underwent fetal intervention were born premature. Lung enlargement with increased lung-to-body weight ratio was observed with fetal tracheal occlusion, accompanied by lower than normal radial alveolar counts and increased alveolar size. Patients treated with tracheal occlusion also had early alveolar development (at 29.8, 30.6, and 30.9 wk postconceptual age) as well as mucous fluid pooling in airways and alveoli. All cases showed severe alveolar septal widening, more extensive in patients without fetal intervention. When grouped by postconceptual age, no statistically significant difference was found between patients with and without fetal intervention with respect to lung-to-body weight ratio, radial alveolar count, mean alveolar length, and relative arteriolar media thickness. Lung enlargement has been observed with fetal tracheal occlusion sonographically; our studies suggest that this is due in part to emphysema and mucous fluid pooling. The lung remains abnormal with low radial alveolar counts and increased alveolar size. Tracheal occlusion did not prevent development of lung pathology associated with pulmonary hypoplasia.

Diaphragmatic function in infants with surgically corrected anomalies

Infants with surgically correctable anomalies, abdominal wall defects (AWD) or congenital diaphragmatic hernia (CDH) may have poor postnatal diaphragmatic function, because the low intra-abdominal pressure experienced by such patients in utero could result in impaired diaphragmatic development. Our objective was to compare postoperative diaphragmatic function of infants with CDH or AWD to that of gestational age-matched controls. Diaphragmatic function was assessed by measurement of the transdiaphragmatic pressure and maximum inspiratory pressure at the mouth generated during crying against an occlusion. In addition, the transdiaphragmatic pressure produced by unilateral and/or bilateral magnetic stimulation of the phrenic nerves (TwPdi) was examined. Lung volume was assessed by measurement of functional residual capacity (FRC) using a helium gas dilution technique. Ten infants with CDH, 26 with AWD infants (19 gastroschisis, seven exomphalos), and 36 gestational age-matched controls were studied. Compared with their matched controls, the eight CDH infants with left-sided defects had significantly lower left (p < 0.01) and right (p < 0.05) TwPdi and FRC (p < 0.01), and the gastroschisis infants, but not those with exomphalos, had significantly lower left and right TwPdi (p < 0.05). There were no significant differences in transdiaphragmatic pressure and maximum inspiratory pressure at the mouth between the CDH or AWD infants and the controls. Diaphragmatic function postoperatively is impaired in infants with CDH or gastroschisis.

Congenital diaphragmatic hernia: advances in prenatal therapy

Despite intensive clinical and experimental efforts, mortality from CDH remains high. More than two decades of research in multiple centers has led to a better understanding of the pathophysiology, prognosis, and treatment options for fetuses that have CDH. It now appears that fetuses that have prenatally diagnosed CDH can be stratified into high- and low-risk groups based upon sonographic parameters. Fetuses that do not have liver herniation into the chest that have a favorable LHR have an excellent chance of survival with postnatal therapy. Prenatal diagnosis allows the time and place of delivery to be planned in advance so these infants can be treated in a tertiary care nursery that has maximal medical and surgical therapy. Fetuses that have liver herniation into the chest and an unfavorable LHR have a grim prognosis. These fetuses might benefit from in utero intervention. There is no role for open fetal repair of the diaphragmatic detect; however, fetoscopic temporary tracheal occlusion might improve lung growth and development and might decrease morbidity and mortality in these infants. The FETENDO strategy appears to work, and for the first time it offers hope to the fetus that has high-risk CDH, but its efficacy must be proven in a proper randomized, controlled trial.

Expanded application of extracorporeal membrane oxygenation in a pediatric surgery practice

OBJECTIVE

To examine the breadth of application and resulting outcomes in a university-based extracorporeal membrane oxygenation (ECMO) program directed by pediatric surgeons.

SUMMARY BACKGROUND DATA

Several randomized control trials have supported the use of ECMO in neonates with respiratory failure. No comparable data exist for older children and young adults who may be afflicted with a variety of uncommon conditions. The indications for ECMO in these patients remain controversial.

METHODS

Patient data were recorded prospectively and reported to the Extracorporeal Life Support Organization. These data were analyzed by indications and outcomes on all patients treated since the inception of the program.

RESULTS

Two hundred sixteen patients were treated with 225 courses of ECMO. Neonates (188 [87%]) outnumbered 28 older patients (aged 6 weeks to 22 years). Overall, 174 patients survived (81%). Sixty-four of 65 (98.5%) neonates with meconium aspiration syndrome survived. ECMO support after heart (3), lung (2), heart-lung (1), and liver (1) transplant yielded a 57% survival to discharge. ECMO also resulted in survival of patients with uncommon conditions, including severe asthma (1), hydrocarbon aspiration (1/2), congestive heart failure due to a cerebral arteriovenous malformation (1), tracheal occlusion incurred during endoscopic stent manipulation (2), meningitis (1), and viral pneumonia (3/5).

CONCLUSIONS

ECMO can potentially eliminate mortality for meconium aspiration syndrome. Survival for other causes of respiratory failure in neonates and older children, while not as dramatic, still surpasses that anticipated with conventional therapy. Moreover, survival of transplant patients has been comparable to that achieved in other children.

Current therapy of infants with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a life-threatening anomaly with a significant mortality rate. Despite widespread prenatal diagnosis, few parameters have been well defined to aid in prediction of outcome of these infants. Antenatal maternal steroid administration and foetal surgery are not proven interventions. Postnatal treatment has changed over the last 10 years, with avoidance of hyperventilation and ventilator-induced lung injury resulting in improved survival. Therapies such as inhaled nitric oxide, exogenous surfactant administration and extracorporeal membrane oxygenation (ECMO) have undergone limited study, but show no clear benefit in this population. With improved outcome, principally due to avoidance of barotrauma, greater opportunity exists for long-term evaluation of survivors. To date, continuing problems with pulmonary function, nutrition and growth, effects of right ventricular hypertension and developmental issues have been identified. Through co-ordinated, multidisciplinary evaluation of CDH survivors, improved long-term outcome for these challenging patients can be attained.

Airway smooth muscle changes in the nitrofen-induced congenital diaphragmatic hernia rat model

In the fetal rat, nitrofen induces congenital diaphragmatic hernia (CDH) and pulmonary vascular remodeling similar to what is observed in the human condition. Airway hyperactivity is common in infants with CDH and attributed to the ventilator-induced airway damage. The purpose of this study was to test the hypothesis that airway smooth muscle mechanical properties are altered in the nitrofen-induced CDH rat model. Lungs from nitrofen-exposed fetuses with hernias (CDH) or intact diaphragm (nitrofen) and untreated fetuses (control) were studied on gestation d 21. The left intrapulmonary artery and bronchi were removed and mounted on a wire myograph, and lung expression, content, and immunolocalization of cyclooxygenases COX-1 and COX-2 were evaluated. Pulmonary artery muscle in the CDH group had significantly (p < 0.01) lower force generation compared with control and nitrofen groups. In contrast, the same generation bronchial smooth muscle of the CDH and nitrofen groups developed higher force compared with control. Whereas no differences were found in endothelium-dependent pulmonary vascular muscle tone, the epithelium-dependent airway muscle relaxation was significantly decreased (p < 0.01) in the CDH and nitrofen groups. The lung mRNA levels of COX-1 and COX-2 were increased in the CDH and nitrofen groups. COX-1 vascular and airway immunostaining, as well as COX-1 and COX-2 lung protein content, were increased in the CDH group. This is the first report of airway smooth muscle abnormalities in the nitrofen-induced fetal rat model of CDH. We speculate that congenital airway muscle changes may be present in the human form of this disease.

Analysis of an improved survival rate for congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Congenital diaphragmatic hernia (CDH) is a condition associated with significant mortality. This study examines the survival rate of neonates with CDH treated by a multidisciplinary team in a single pediatric hospital. Actual survival rate is compared with predicted outcome based on severity of illness.

METHODS

A consecutive series of neonates with CDH was evaluated beginning January 1, 2000. There were no excluded patients. A treatment protocol emphasizing minimal barotrauma and control of pulmonary hypertension was used. Predicted survival rate was estimated using birth weight and Apgar score at 5 minutes per the logistic regression equation published by the CDH Study Group. Actual survival rates were calculated and compared with predicted values using a one sample binomial test with significance deemed to be present at P less than.05.

RESULTS

Thirty-six of 39 (93%) neonates with CDH survived, whereas the predicted survival rate for this cohort was 68% (P <.001). Twelve of 14 (86%) neonates requiring extracorporeal membrane oxygenation (ECMO) survived, despite a predicted survival rate of 52% for this subset (P <.01). Twenty-five percent of survivors required supplemental oxygen at home.

CONCLUSIONS

Using a simple analysis, centers may now objectively compare their CDH survival rates with predicted outcomes adjusted for disease severity. This technique confirmed that a consecutive series of neonates with CDH, treated in one hospital, had a significantly higher than predicted survival rate. Thus, it may be possible to identify other centers with higher than expected survival rates and to define common therapeutic strategies associated with decreased mortality.

Outcome at 2 years of infants with congenital diaphragmatic hernia: a population-based study

BACKGROUND

Management of neonates with congenital diaphragmatic hernia (CDH) has undergone many changes associated with increased survival of high-risk CDH. However, little is known about the long-term outcome of CDH infants.

METHODS

Follow-up was performed in 85 newborn infants with CDH admitted in our neonatal intensive care unit between January 1991 and December 1998. Early (< 2 months) and late mortality (> or = 2 months), and respiratory, nutritional, musculoskeletal, and neurosensory outcome at 2 years were recorded.

RESULTS

Surgical repair was performed in 59 infants (69%) at a median postnatal age of 124 (range, 38 to 246) hours. Extracorporeal membrane oxygenation was used in 26 (30%) newborn infants. Survival at 2 years was 51 of 85 (60%) (early death, 28/85 [33%]; late death, 6/85 [7%]). Late deaths occurred because of persistent pulmonary hypertension or iatrogenic complications. Twelve of 51 (24%) newborn infants were oxygen dependant at the postnatal age of 28 days, and 1 of 51 (1.9%) was still oxygen dependant at 2 years. Growth failure was noted in 9 of 51 (18%), mainly related to severe gastroesophageal reflux and oral aversion. Scoliosis was diagnosed in 2 infants. Neurologic examination at 2 years was normal in 45 of 51 (88%). Cerebral palsy and developmental delay were observed in 2 and 4 infants, respectively. Four infants (8%) experienced associated problems. Respiratory, nutritional, and musculoskeletal morbidity was higher in infants treated by extracorporeal membrane oxygenation (p < 0.05).

CONCLUSIONS

CDH infants are at risk for adverse nutritional and respiratory outcome. Despite severe respiratory failure at birth, prolonged oxygen therapy above 2 years of age is uncommon. Conversely, failure to thrive related at least in part to gastroesophageal reflux and oral dysfunction remains the major problem at 2 years of age. However, both nutritional and respiratory problems tend to improve with age.

Perinatal management and outcome of prenatally diagnosed congenital diaphragmatic hernia: a 1995-2000 series in Rennes University Hospital

OBJECTIVES

To assess the prognosis of prenatally diagnosed congenital diaphragmatic hernia (CDH) during the years 1995-2000 in order to improve prenatal counselling.

METHODS

Retrospective study of all 31 cases of women with prenatally diagnosed CDH.

RESULTS

Nine pregnancies (29%) were terminated and two fetuses (6%) were stillborn. Ten fetuses (32%) had associated anomalies (four Fryns' syndrome) and four (13%) had underlying chromosomal anomalies. Twenty pregnancies were continued. Seven babies died before surgery either immediately in the delivery room (five between 1 and 45 min), or during the 'stabilisation period' (two babies, 7 and 21 h). Three babies presented with trisomy 18, Fryns' syndrome or transposition of the great arteries with microdeletion 22q11. Thirteen babies had the defect repaired (median 18 h, range 4-72 h) and 12 survived. Mechanical ventilation was required for a median of 12 days. One survivor has cerebral palsy.

CONCLUSION

Of 31 prenatally diagnosed CDH cases 38% are alive, of 20 ongoing pregnancies 60% are alive, and of 13 babies who underwent surgery 92% are alive. No baby with associated malformations survived. These numbers need to be known by each member of the counselling team in order to give parents adequate information to make their decision.

The cost-effectiveness of treatment for congenital diaphragmatic hernia

BACKGROUND/PURPOSE

The cost-effectiveness of medical interventions is becoming an important issue for decision makers. Until recently, evidence of the cost-effectiveness of neonatal surgery was largely lacking. The authors analyzed the cost-effectiveness of neonatal surgery and subsequent treatment for congenital diaphragmatic hernia (CDH).

METHODS

Both costs incurred inside and outside the health care sector (eg, out-of-pocket expenses and productivity losses) were included. Quality-adjusted life years (QALYs) were measured using the EuroQol EQ-5D questionnaire. Descriptive quality-of-life data were collected using a disease-specific questionnaire. Both costs and effects basically were measured in a life-time setting.

RESULTS

Total costs of treatment average euro 42,658, mainly consisting of costs of the initial hospitalization. Productivity losses in both the patients and their caregivers appear to be minor. Treated CDH patients, even adults, suffer from respiratory difficulties and stomach aches. According to the EQ-5D, however, their quality of life does not differ from the general population, suggesting that these symptoms barely affect overall quality of life. Treatment results in a gain of 17.5 QALYs. Costs per QALY amount to euro 2,434.

CONCLUSIONS

Treatment for CDH has favorable cost-effectiveness. Considering the growing importance of cost-effective medicine, these are important and encouraging results. Health economics outlines the inevitability of making choices that directly affect patient care and places relative values on different health care programs. The results of this study provide convincing evidence that treatment for CDH is indeed cost effective.

Congenital diaphragmatic hernia

Congenital diaphragmatic hernia occurs in approximately 1 in every 2500 live births and is associated with a reported mortality of almost 35% in live-born patients and a higher mortality when in utero deaths are counted. Ventilator-induced lung injury, pulmonary hypoplasia, and other associated anomalies account for the high death rate. Numerous adjunctive measures have been used to treat these patients. Inhaled vasodilators (nitric oxide), intravenous vasodilators, and fetal therapy have no proven benefit. While animal models of congenital diaphragmatic hernia are surfactant deficient, controversy remains over the use of surfactant in infants. There has been no clinical trial showing any clear benefit with the use of exogenous surfactant in these patients. Similarly, prenatal corticosteroids show some improvements in animal models, but again, there is a complete absence of supportive data to show benefit in humans. Mechanical ventilator strategies that limit ventilator-induced lung injury by avoiding hyperventilation and lung over inflation are the strategies currently in use that have been associated with improved survival. Long-term follow-up of these patients is quite important since gastroesophageal reflux, developmental delay, chronic lung disease, and chest wall deformity are all seen with increased frequency in these children.

Nutritional morbidity in survivors of congenital diaphragmatic hernia

PURPOSE

The purpose of this report is to detail the nutritional sequelae seen in survivors of congenital diaphragmatic hernia (CDH) followed in a multidisciplinary clinic.

METHODS

Data on 121 surviving CDH patients seen between 1990 and 2000 were collected. Regression analysis was used to determine the impact of factors such as Apgar score, birth weight, extracorporeal membrane oxygenation (ECMO), and patch repair on outcomes associated with nutritional morbidity.

RESULTS

There were 100 left and 21 right CDH defects. Mean birth weight and 5-minute Apgar score were 3.1 kg (+/-0.8) and 6.8(+/-2), respectively. Extracorporeal membrane oxygenation was required in 43 (36%) patients and patch repair in 39 (32%). A gastrostomy was required in 39 (32%) patients and a fundoplication in 23 (19%) patients. The side of the defect did not affect the frequency of these procedures. Fifty-six percent of patients were below the 25th percentile for weight during most of their first year. Regression analysis found that duration of ventilation (P <.001) and the presence of a patch repair (P =.03) were independent variables predictive of failure to thrive thereby requiring a gastrostomy tube. Patch repair also was predictive of need for subsequent fundoplication caused by gastroesophageal reflux (P <.001). Twenty-nine patients (24%) had severe oral aversion. Risk factors were prolonged ventilation (P =.001) and oxygen requirement at discharge (P =.015). Two thirds of these patients subsequently improved.

CONCLUSIONS

Nutritional problems continue to be a source of morbidity for survivors of CDH, particularly in the first year of life. Not surprisingly, patients who had prolonged intubation and prosthetic material at the gastroesophageal junction fared worse. Despite aggressive nutritional management, 56% of the population remained below the twenty-fifth percentile for weight. These data show the need for careful nutritional assessment in all CDH patients, especially those at high risk for malnutrition.