Congenital diaphragmatic hernia: predictors of severity in the ECMO era

A new approach using image analysis to assess pulmonary hypoplasia in the fetal lamb diaphragmatic hernia model

BACKGROUND

In congenital diaphragmatic hernia (CDH), there is pulmonary hypoplasia (PH) and also pulmonary vascular and bronchial abnormalities. Few studies have investigated bronchial maldevelopment in CDH. We evaluated bronchial area (BA) by bronchography in a fetal lamb DH model to develop a measure of PH.

METHODS

We created DH in fetal lambs at 75 days gestation, delivering by cesarean section and killing them at term (DH, n = 12). Normal term fetuses provided controls (C, n  = 5). We measured total lung volume (TLV) and performed barium bronchography. Using image analysis, BA, total lung area (TLA) and bronchial area/lung area ratio (B/L ratio) were calculated. Student's T test (p < 0.05; significant) and Spearman's correlation coefficient were performed.

RESULTS

TLV (ml) was 133.3 ± 41.2 in DH and 326 ± 22.5 in C (p = 0.0000001). TLA (cm²) was 78.8 ± 17.4 in DH and 107.1 ± 10.3 in C (p = 0.006). BA (cm²) was 39.6 ± 11.9 in DH and 52.2 ± 7.7 in C (p = 0.019). The B/L ratio was 0.45 ± 0.06 in DH and 0.49 ± 0.05 in C (p = 0.28). There are correlations in DH between TLV and TLA (r = 0.79), TLV and BA (r = 0.73) and in C between TLV and TLA (r = 0.97) and TLV and BA (r = 0.67).

CONCLUSION

It may be possible to assess PH on fetal MRI, given the correlation between TLV and TLA, and TLV and BA.

Comparison of early postnatal prediction models for survival in congenital diaphragmatic hernia

OBJECTIVE

To compare the PF-PCO₂ equation-partial pressure of arterial oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) minus partial pressure of carbon dioxide (PCO₂)-to three other tools for postnatal prediction of survival in infants with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

A retrospective analysis of 203 infants with CDH from 1 January 2003 to 30 June 2018. Area under the curve (AUC) analysis was performed for survival and secondary outcomes of survival without extracorporeal membrane oxygenation support (ECMO) and death despite ECMO. Predictive scores were calculated to determine cutoff for PF-PCO₂ score.

RESULTS

The PF-PCO₂ tool had the highest AUC (0.84 for survival, 0.92 for survival without ECMO, and 0.83 for death despite ECMO). PF-PCO₂ best predicted survival when >-60 and survival without ECMO when >+80. There was no optimal cutoff score for death despite ECMO.

CONCLUSION

The PF-PCO₂ tool best predicted postnatal survival in infants with CDH.

Repair of congenital diaphragmatic hernia during extracorporeal life support: experience with six neonates

BACKGROUND

The management of congenital diaphragmatic hernia (CDH) in neonates has evolved considerably over the last three decades. Initial stabilization followed by surgical repair is the current standard of care. A subset fails to achieve adequate oxygenation with medical management, including the use of high frequency oscillation and inhaled nitric oxide. The mortality in this group exceeds 80% without additional management strategies. Extracorporeal life support (ECLS) is a well-established modality for managing these neonates with CDH and has been shown to improve early survival in selected cases.

METHODS

This is a retrospective analysis of six neonates with CDH who underwent repair during ECLS between September 2011 and November 2014.

RESULTS

Of 24 admissions with CDH, there were six neonates (25%) who required ECLS. All the six had CDH repair during ECLS. There were no intra-operative bleeding complications. There were no clotting complications related to stopping heparin during CDH repair. There was one hospital death. Five neonates were weaned from ECLS and discharged home.

CONCLUSIONS

Data from our small cohort of patients illustrate that early survival is possible in extremely compromised neonates who otherwise would have died without ECLS. Our experience demonstrates that CDH repair can safely be performed during ECLS. Use of ECLS, early repair during ECLS, lung protective ventilation strategies and aggressive management of pulmonary hypertension were associated with good early survival. ECLS should be considered as an integral part of therapeutic armamentarium for CDH in neonates.

Congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia (CDH) is defined by the presence of an orifice in the diaphragm, more often left and posterolateral that permits the herniation of abdominal contents into the thorax. The lungs are hypoplastic and have abnormal vessels that cause respiratory insufficiency and persistent pulmonary hypertension with high mortality. About one third of cases have cardiovascular malformations and lesser proportions have skeletal, neural, genitourinary, gastrointestinal or other defects. CDH can be a component of Pallister-Killian, Fryns, Ghersoni-Baruch, WAGR, Denys-Drash, Brachman-De Lange, Donnai-Barrow or Wolf-Hirschhorn syndromes. Some chromosomal anomalies involve CDH as well. The incidence is < 5 in 10,000 live-births. The etiology is unknown although clinical, genetic and experimental evidence points to disturbances in the retinoid-signaling pathway during organogenesis. Antenatal diagnosis is often made and this allows prenatal management (open correction of the hernia in the past and reversible fetoscopic tracheal obstruction nowadays) that may be indicated in cases with severe lung hypoplasia and grim prognosis. Treatment after birth requires all the refinements of critical care including extracorporeal membrane oxygenation prior to surgical correction. The best hospital series report 80% survival but it remains around 50% in population-based studies. Chronic respiratory tract disease, neurodevelopmental problems, neurosensorial hearing loss and gastroesophageal reflux are common problems in survivors. Much more research on several aspects of this severe condition is warranted.

Anaesthesia for urgent and emergency surgery

The general principles that guide a pediatric anesthesiologist in the care of a newborn needing urgent and emergent neonatal surgery are reviewed. These include careful evaluation and assessment of the newborn including a detailed prenatal history. A brief review of neonatal physiology including the development of the autonomic nervous system and the development of nociceptive pathways is discussed and how important it is to suppress the stress response to surgical intervention in order to improve surgical outcomes. Most of the current general anesthetics have been associated with anesthetic neurotoxicity in juvenile mammals and several epidemiologic studies in human infants and toddlers have linked surgery occurring in the first 3 years of life with neurocognitive delays in school age children. These concerns are discussed in this paper. Practical considerations about neonatal intubation, line placement and intraoperative fluid management are also reviewed. And the anesthetic management of specific neonatal conditions such as congenital diaphragmatic hernias, transesophageal fistulas, gastroschisis and omphaloceles, necrotizing enterocolitis and meningomyeloceles is examined.

Predictors of survival in congenital diaphragmatic hernia patients requiring extracorporeal membrane oxygenation: CNMC 15-year experience

OBJECTIVE

To review outcomes of patients with congenital diaphragmatic hernia (CDH) requiring extracorporeal membrane oxygenation (ECMO) at a level IIIC neonatal intensive care unit and to determine if pre-ECMO respiratory status can help predict mortality.

STUDY DESIGN

A single-center retrospective chart review was conducted on all infants with CDH treated with ECMO in the past 15 years. Demographic and clinical information, including pre-ECMO ventilatory and blood gas data, was collected. Differences between survivors and non-survivors were evaluated using independent samples t-/Mann-Whitney U-and Fisher's exact/chi (2)-tests for continuous and categorical data, respectively. Cox regression analysis was performed to evaluate predictors of survival while controlling for covariates. Significant predictors were further explored with receiver operating characteristic (ROC) curve and Kaplan-Meier survival analysis.

RESULT

Overall survival of the population of 62 patients treated with ECMO was 50%. Survivor and non-survivors were similar in birth weight, gestational age, gender, race and Apgar scores. Approximately 80% of patients in both groups had a left-sided defect. Less than half of patients were prenatally diagnosed in either group. Patients in the non-survivor group had associated anomalies (42 vs 23% for survivors) but this was not statistically significant (P=0.303). Non-survivors were more likely to be put on ECMO earlier, stay on ECMO longer and be operated upon later. On pre-ECMO blood gas analyses, survivors had higher pH and PaO(2), and lower oxygenation index and PaCO(2) compared with non-survivors. After controlling for covariates, a lower minimum PaCO(2) and side of defect were the only independent predictors of survival. ROC curve for minimum pre-ECMO PaCO(2) had a significant area under the curve (0.72, P=0.003). Survival was 27% in babies unable to achieve a pre-ECMO PaCO(2) <60 mm Hg whereas no patients survived if their lowest pre-ECMO PaCO(2) was >70 mm Hg.

CONCLUSION

Minimum achievable pre-ECMO PaCO(2) is an independent predictor of survival in patients with CDH requiring ECMO life support. These data provide useful prognostic information for counseling families and may facilitate direction of care in extreme cases where the degree of pulmonary hypoplasia may be incompatible with life.

Evaluating mortality and disease severity in congenital diaphragmatic hernia using the McGoon and pulmonary artery indices

PURPOSE

Lung hypoplasia is associated with mortality in congenital diaphragmatic hernia (CDH). However, the association between lung hypoplasia and disease severity is unclear. Early prediction of disease severity would provide parents with more precise information about the anticipated course of treatment, minimize treatment disruption, and maximize the efficient management of patients with CDH. We aimed at identifying the relationship between McGoon index (MGI) and pulmonary artery index (PAI) scores and disease severity among infants with CDH.

METHODS

We retrospectively reviewed the medical records of 19 high-risk patients with CDH born between January 2006 and December 2007. McGoon index and PAI scores were determined on admission. We evaluated statistically the relationship between these scores and variables representing severity as follows: number of vasodilators, use of inhaled nitric oxide (iNO), closed method of diaphragm, duration of intubation, duration of hospitalization, and use of home oxygen therapy. Statistical significance was P < .05.

RESULTS

Overall median MGI and PAI scores were 1.40 and 108, respectively; scores for nonsurvivors were significantly (P < .05 and P < .01, respectively) lower than those for survivors. Among survivors, PAI scores were significantly (P < .05) lower in infants requiring iNO than in infants not requiring iNO and patch repair. The PAI scores were significantly correlated with the number of vasodilators (r = -0.789; P < .01) and duration of intubation (r = -0.610; P < .05).

CONCLUSIONS

McGoon index (cutoff value, 1.31) and PAI (cutoff value, 90) are reliable indices for predicting mortality in CDH. Pulmonary artery index appears to be more useful than MGI for predicting disease severity among survivors.

Fetal preload index of the inferior vena cava and neonatal outcome of congenital diaphragmatic hernia

PURPOSE

The purpose of this study was to assess prognostic factors in patients with congenital diaphragmatic hernia (CDH).

METHODS

Thirteen patients with CDH diagnosed antenatally and delivered in our hospital between 1995 and 2006 were retrospectively studied. Assessments of sonographic examinations included gestational age at time of diagnosis; the ultrasonographic parameters [amniotic fluid index, cardiothoracic area ratio, and the lung-thoracic transverse area ratio (LTR)]; and the incidence of polyhydramnios, intrauterine growth retardation, and hydrops. Doppler velocimetry measurements comprised the resistance index of the umbilical artery, the resistance index of the midcerebral artery, the maximal velocity of the descending aorta, and the preload index of the inferior vena cava (IVCPLI). Results were expressed as the mean ± standard deviation. The features of survivors and nonsurvivors were compared.

RESULTS

Six fetuses were survivors and seven were nonsurvivors. The mean LTR value tended to be markedly low in both groups (23.8 ± 16.4 vs 12.1 ± 1.1). In Doppler analysis, the mean IVCPLI value in survivors was significantly lower than that in nonsurvivors (0.34 ± 0.08 vs 0.52 ± 0.14, P = 0.01).

CONCLUSION

We concluded that fetal IVCPLI might be a good predictor of the outcome in patients with CDH.

Predictors and statistical models in congenital diaphragmatic hernia

Despite advances in intensive care, congenital diaphragmatic hernia (CDH) maintains a risk of death >35%. Mortality predictors have been claimed, using logistic regression. When the outcome of interest is rare (i.e. <20%), the odds ratio, measured by logistic regression, is approximately equal to the relative risk, calculated by log-binomial model. However, for common events, the odds ratio misleads the exposition risk. The aims are to identify independent predictors of mortality in high-risk CDH, using the log-binomial model and disclose if the exposition risks could differ applying in comparison the logistic regression. Details of 113 consecutive high-risk CDH neonates, baseline demographics and disease features were collected retrospectively. Log-binomial model and logistic regression were applied and compared. Overall mortality rate was 41.6% (47/113). The log-binomial model identified preoperative pneumothorax (pnx), birth weight < or = 2,500 g and liver herniation as independent mortality predictors; female gender, an advanced gestational age and a PaO(2) > or = 90 mmHg as protective factors. Using logistic regression, liver herniation and birth weight did not maintain the significance. The exposition risks for pnx, female gender and gestational age were overestimated. The odds ratio measured by logistic regression overestimated the exposition risks. Since the mortality rate is confirmed to be >20% and the exposition risks, measured by logistic regression, are misleading, the log-binomial model should be consider in CDH binary outcome studies. According to the mortality predictors identified, making every effort to plan delivery at term and lowering the risk of pnx could improve the outcome.

Congenital diaphragmatic hernia: a systematic review and summary of best-evidence practice strategies

OBJECTIVES

Recent reports suggest that specific care strategies improve survival of infants with congenital diaphragmatic hernia (CDH). This review presents details of care from centers reporting high rates of survival among CDH infants.

STUDY DESIGN

We conducted a MEDLINE search (1995 to 2006) and searched all citations in the Cochrane Central Register of Controlled Trials. Studies were included if they contained reports of >20 infants with symptomatic CDH, and >75% survival of isolated CDH.

RESULT

Thirteen reports from 11 centers met inclusion criteria. Overall survival, including infants with multiple anomalies, was 603/763 (79%; range: 69 to 93%). Survival for isolated CDH was 560/661 (85%; range: 78 to 96%). The frequency of extracorporeal membrane oxygenation (ECMO) use for isolated CDH varied widely among reporting centers 251/622 (40%; range: 11 to 61%), as did survival for infants with isolated CDH placed on ECMO: 149/206 (73%; range: 33 to 86%). There was no suggestion of benefit from use of antenatal glucocorticoids given after 34 weeks gestation or use of postnatal surfactant. Low mortality was frequently attributed to minimizing lung injury and adhering to center-specific criteria for ECMO.

CONCLUSION

Use of strategies aimed at minimizing lung injury, tolerance of postductal acidosis and hypoxemia, and adhering to center-specific criteria for ECMO were strategies most consistently reported by successful centers. The literature lacks randomized clinical trials of these or other care strategies in this complex patient population; prospective studies of safety and long-term outcome are needed.

Extralobar sequestration with congenital diaphragmatic hernia: a complicated case study

This article presents a case study of an infant (JG) with an antenatal diagnosis of a left diaphragmatic hernia and an extralobar sequestration of his right lung, which was noted postnatally. JG's course was complicated by persistent pulmonary hypertension of the newborn (PPHN) and suspected pulmonary hypoplasia, and he required support with extracorporeal life support (ECLS). JG's case was unusual in his presentation of extreme PPHN that was unresponsive to inhaled nitric oxide and ECLS. His PPHN was nearly intractable, requiring treatment with vasodilators combined with intravenous sildenafil, which had never been tried in our institution before this case. The article concludes with a discussion of the etiology, diagnosis, and management of congenital diaphragmatic hernia and extralobar sequestration, singly and in combination.

Severe complications during the management of a child with late presentation of a diaphragmatic hernia

We report on a 3-year-old boy with late presentation of congenital diaphragmatic hernia who developed cardiac arrest after induction of anaesthesia. The paper discusses the anaesthetic technique, in particular ventilation during and after induction, how these techniques contributed to the complication, and how they might have been avoided.

Artificial lungs: a new inspiration

An estimated 16 million Americans are afflicted with some degree of chronic obstructive pulmonary disease (COPD), accounting for 100,000 deaths per year. The only current treatment for chronic irreversible pulmonary failure is lung transplantation. Since the widespread success of single and double lung transplantation in the early 1990s, demand for donor lungs has steadily outgrown the supply. Unlike dialysis, which functions as a bridge to renal transplantation, or a ventricular assist device (VAD), which serves as a bridge to cardiac transplantation, no suitable bridge to lung transplantation exists. The current methods for supporting patients with lung disease, however, are not adequate or efficient enough to act as a bridge to transplantation. Although occasionally successful as a bridge to transplant, ECMO requires multiple transfusions and is complex, labor-intensive, time-limited, costly, non-ambulatory and prone to infection. Intravenacaval devices, such as the intravascular oxygenator (IVOX) and the intravenous membrane oxygenator (IMO), are surface area limited and currently provide inadequate gas exchange to function as a bridge-to-recovery or transplant. A successful artificial lung could realize a substantial clinical impact as a bridge to lung transplantation, a support device immediately post-lung transplant, and as rescue and/or supplement to mechanical ventilation during the treatment of severe respiratory failure.

A statistical model to predict nonsurvival in congenital diaphragmatic hernia

OBJECTIVE

To develop a predictive model using echocardiographic indices to identify nonsurvivors from survivors in preoperative patients with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

Eight cases of CDH, with a mortality rate of 38%, underwent echocardiographic study before surgical repair. Left ventricular mass (LVMASS) using the area-length method of Wyatt et al. and fractional shortening (FS) by M-mode measurements were determined.

RESULTS

We identified a nonlinear nonoverlapping distribution that predicted nonsurvivors from survivors, p=0.04. Multiple regression analysis demonstrated the quantity (LVMASS x FS)(1/2) to be correlated with nonsurvival with a coefficient of determination r(2)=0.55. Comparison of the means of the quantity (LVMASS x FS)(1/2) for the two groups suggested two distinct populations, p=0.04.

CONCLUSION

The mathematical quantity (LVMASS x FS)(1/2) calculated from echocardiographic measurements obtained preoperatively in babies with CDH may predict nonsurvival despite maximal intervention.

Extracorporeal membrane oxygenation for severe respiratory failure

The use of extracorporeal technology to accomplish gas exchange with or without cardiac support is based on the premise that "lung rest" facilitates repair and avoids the baso- or volutrauma of mechanical ventilator management. Extracorporeal membrane oxygenation (ECMO), a modified form of cardiopulmonary bypass, has been shown to decrease mortality of neonatal, pediatric and adult respiratory failure and is capable of total gas exchange. In neonates, over 20,638 patients have been treated with an overall survival of 77% in a population thought to have 78% mortality.

Airway anomalies in patients with congenital diaphragmatic hernia

PURPOSE

Congenital diaphragmatic hernias (CDH) sometimes are associated with airway anomalies such as congenital stenosis, abnormal branching of the bronchi, and pulmonary hypoplasia. The incidence of these associated airway anomalies has not been reported previously.

METHODS

Bronchoscopy was performed in all neonates with CDH from 1987 to 1999. In addition to anatomic anomalies, bronchial hypoplasia was defined as narrowing and shortening of the bronchi at bronchoscopy.

RESULTS

Anatomic anomalies were identified in 7 of 39 patients with CDH: 1 had congenital tracheal stenosis with pulmonary artery sling, 1 had a defect of the right upper lobe bronchus, 2 had a tracheal bronchus, and 3 had a trifurcated trachea. Bronchial hypoplasia on the affected side was identified in 15 patients and was seen in all patients with anatomic anomalies of the tracheobronchial tree except the 2 with tracheal bronchus. After excluding 5 patients with severe associated anomalies, 6 of 14 patients with an abnormal tracheobronchial tree died, whereas 1 of 20 patients without airway abnormalities died.

CONCLUSIONS

Anatomic anomalies of the tracheobronchial tree and bronchial hypoplasia on the affected side were identified in 17.9% and 38.4% of patients with CDH, respectively. CDH patients who exhibited these abnormalities showed a poor outcome.

Echocardiographic predictors of outcome in newborns with congenital diaphragmatic hernia

OBJECTIVE

Despite new treatments, congenital diaphragmatic hernia (CDH) still has high mortality. The aim of this study was to identify echocardiographic predictors of outcome in newborns with an isolated CDH.

METHODS

We reviewed medical charts and echocardiograms of 40 newborns who presented with CDH in the first 24 hours of life, from 1992 to 1996. We compared the cardiac valves and great arteries diameters, left-ventricular volume and mass, Apgar scores, and modified McGoon index (the combined diameter of hilar pulmonary arteries, indexed to the descending aorta) of survivors and nonsurvivors. We performed Student's t test and multiple logistic regression analysis between the 2 groups.

RESULTS

Fourteen patients died 1 to 33 days after birth (median: 3 days), including 8 from progressive hypoxemia without operation; 26 have survived up to 5 years (median: 2 years) after successful operations. Nonsurvivors had significantly smaller diameters of right and left hilar pulmonary arteries, more frequent right-sided CDH, and lower mean Apgar scores at 1 and 5 minutes. The most significant prognostic factor was the modified McGoon index. A modified McGoon index </=1.3 predicted mortality with a sensitivity of 85% and specificity of 100%.

CONCLUSION

Echocardiographic measurement of hilar pulmonary arteries, which may represent the adequacy of the pulmonary vascular bed, is a strong prognostic factor for newborns with congenital CDH.

Remodeling of pulmonary arteries in human congenital diaphragmatic hernia with or without extracorporeal membrane oxygenation

PURPOSE

The aim of this study was to describe in detail the perinatal developmental profile of the pulmonary vasculature in congenital diaphragmatic hernia (CDH) and to examine the potential beneficial effects of extracorporeal membrane oxygenation (ECMO) on the vascular morphology. Additionally the authors aimed to identify the differences in pulmonary vascular morphology among CDH cases according to the primary cause of death: either extreme lung hypoplasia (LH) or persistent pulmonary hypertension (PPH).

METHODS

The authors studied autopsy sections from 30 high-risk CDH cases with respect to the pulmonary arteries in relation to gestational age (GA) and ECMO treatment. They were grouped into CDH-I: 20 cases with GA greater than 34 weeks who were not subjected to ECMO and CDH-II: 10 cases with GA greater than 34 weeks, who were subjected to ECMO for an average time of 237 hours. Five age-matched neonates who died from placental insufficiency or birth asphyxia without evidence of lung hypoplasia served as controls (CON). Medial and adventitial thicknesses of pulmonary arteries were measured in lung sections stained with Elastic van Gieson by 2 investigators blinded for the clinical data. Immunohistological staining with anti-alpha-smooth muscle actin (alpha-SMA) was performed to confirm the precise location of the arterial media before morphometry. CDH cases were subgrouped and compared according to the primary cause of death. Unpaired Student t test was used for statistics, with significant P value < or =.05.

RESULTS

In CDH newborns, a significant increase in medial, adventitial, and total wall thickness was found in pulmonary arteries with an external diameter of less than 200 microm as compared with age-matched controls (P<.004, .0001, and .0009, respectively). ECMO-treated CDH newborns showed a significantly thinner arterial adventitia than CDH patients who did not receive this treatment (P<.0001), approaching normal values. However, the medial thickness remained increased. Morphometrically, no significant differences in CDH cases between patients dying of PPH or severe LH could be determined.

CONCLUSIONS

(1) In CDH, there is failure of the normal arterial remodeling processes occurring in the perinatal period. (2) Pulmonary vascular morphology in CDH does not differ between the groups with lung hypoplasia or persistent pulmonary hypertension as primary cause of death. (3) Adventitial thinning of these arteries might be one of the mechanisms by which ECMO alters PPH in CDH cases.

A population-based study of congenital diaphragmatic hernia: impact of associated anomalies and preoperative blood gases on survival

BACKGROUND/PURPOSE

Although neonatal care has improved over the past 20 years, mortality rate with congenital diaphragmatic hernia (CDH) remains 50% to 60%, possibly reflecting differences in management or selection biases. The authors determined the incidence, outcome, effect of coexisting anomalies, and prognostic indicators for neonates with CDH in a single inborn population older than 13 years.

METHODS

Forty-three neonates with CDH, those symptomatic within the first 6 hours of life, were identified using a validated neonatal database and diagnosis coding data from medical records among 180,643 live inborn neonates delivered at Parkland Memorial Hospital between 1983 and 1995. Charts were reviewed for prenatal history, demographic variables, presence of coexisting malformations, preoperative arterial blood gases, surgical findings, and outcome. Survival to hospital discharge was the primary outcome variable.

RESULTS

The incidence of CDH was 1 in 4,200 live births; overall survival rate was 51%. Thirty-two (74%) neonates underwent surgical repair, often at less than 8 hours of life; postoperative mortality rate was 31%. Eighteen (42%) had coexisting major anomalies or chromosomal abnormalities. Eighty percent of neonates with isolated CDH survived, whereas 89% with CDH and associated defects died. Nonsurvivors had lower birth weights and Apgar scores, were more acidotic, and had more severe respiratory compromise. When best preoperative pH was > or = 7.25 or PaCO2 < or = 50 mm Hg, 80% of neonates survived.

CONCLUSION

In this inborn population-based review of neonatal CDH between 1983 and 1995, the best predictors of survival were the presence or absence of other anomalies and the best preoperative PaCO2 and pH.

Is prognostication in congenital diaphragmatic hernia possible without sophisticated investigations?

Congenital diaphragmatic hernia is a complex disorder, in which the anatomical defect is only one part of the spectrum of disease. Hypoplasia of lung complicated by pulmonary hypertension and right to left shunting results in serious hypoxemia. Many factors, based on degree of alterations in respiratory physiology and involving analysis of blood gases and acid base systems, have been used in an attempt to prognosticate the outcome. Majority of these investigations are not available in a modest set up like ours. The case records of all 20 patients admitted and operated for congenital diaphragmatic hernia in pediatric surgery unit of Government Medical College Hospital, Jabalpur from 1978 to 1997 were reviewed retrospectively in an attempt to prognosticate without the sophisticated investigations. It was found that even in a very modestly equipped hospital it is possible to prognosticate--to some extent--the outcome in these cases. Major prognosticators found were APGAR score (if child born in hospital), late age of presentation, location of stomach and identification of hernial sac.

Does extracorporeal membrane oxygenation improve survival in neonates with congenital diaphragmatic hernia? The Congenital Diaphragmatic Hernia Study Group

BACKGROUND/PURPOSE

The benefit of extracorporeal membrane oxygenation (ECMO) in improving survival of neonates with congenital diaphragmatic hernia (CDH) has never been clearly demonstrated. This may be due to comparisons made between treatment groups of unequal illness severity and the low statistical power of analyses from previous studies. The authors analyzed the data from the multicenter CDH registry to determine if ECMO improves survival in CDH neonates with a high risk of mortality.

METHODS

A total of 730 neonates were enrolled in the CDH Registry from January 1995 to November 1997. Of these, 632 neonates had a complete data set and were eligible for ECMO by the weight criterion of greater than 2.0 kg. Multivariate logistic regression analysis was used to assess mortality risk for each neonate based on previously validated independent predictors of survival: birth weight and 5-minute Apgar. Five quintile groups were defined based on increasing predictive mortality risk. Multivariate logistic regression and chi2 analyses with birth weight, Apgar score at 5 minutes, and predictive mortality risk as covariates were then performed to assess survival benefit of ECMO compared with conventional therapy alone. Patient survival rate was defined as survival to discharge from hospital.

RESULTS

When analyzing all 632 neonates, ECMO neonates (n = 289) had a decidedly lower survival rate (52.9% v 77.3%, P< .001) than non-ECMO neonates (n = 343) without standardizing for the degree of illness. However, when taking into account the patients' predictive mortality risk, ECMO was associated with improved survival in the neonates with mortality risk < or = 80% (P < .05). Furthermore, ECMO was shown to be a positive independent predictor of survival when accounting for the covariates of birth weight, 5-minute Apgar, and mortality risk (P < .05).

CONCLUSIONS

ECMO significantly improves survival rates for those CDH neonates with a predictive mortality risk > or = 80%. Generally, the more critically ill the patient with CDH, the more marked the survival benefit obtained.

[Congenital diaphragmatic hernia. II. Is pulmonary hypoplasia an indefinable obstacle?]

Despite major insights into the pathogenesis and pathophysiology of congenital diaphragmatic hernia, and despite the availability of an antenatal diagnosis and continuous progress in neonatal intensive care, little improvement has been obtained in the prognosis of this malformation. Thus obstetricians, neonatologists and pediatric surgeons are still facing a several dilemma: dilemma before birth to predict the prognosis, i.e., to evaluate the severity of the associated pulmonary hypoplasia in order to decide whether or not to interrupt pregnancy; dilemma after birth in case of severe respiratory failure to decide how far to go in life support. Based on a review of the literature and their own experience, the authors attempt to recapitulate the perinatal management and outcome of this severe malformation.

Congenital diaphragmatic hernia: developing a protocolized approach

BACKGROUND/PURPOSE

The purpose of this study was to evaluate the evolving outcome of newborns who have congenital diaphragmatic hernia (CDH) using a protocolized approach to management, which includes extracorporeal membrane oxygenation (ECMO) and to present the details of such a management protocol.

METHODS

A retrospective chart review was conducted of the neonatal outcome of near-term (>34 weeks' gestation) newborns with CDH all referred to the Royal Alexandra Hospital either before or after delivery. A protocol was developed that included antenatal assessment, the use of antenatal steroids, planned delivery, use of prophylactic surfactant, pressure limited gentle ventilation, permissive hypercarbia and hypoxia, and venovenous ECMO, if indicated.

RESULTS

Sixty-five infants with CDH were treated from February 1989 through August 1996. Twenty-three infants were inborn, 20 of whom were antenatal referrals. Overall, 51 of the 65 infants survived (78%). Thirteen of the 23 inborn infants survived with conservative management, and 10 required ECMO, of whom, eight were long-term survivors. Thirty-eight infants required ECMO, and 26 survived (68%), whereas there were only two deaths among the 27 conservatively treated infants. Eighteen of 20 inborn infants with an antenatal diagnosis survived, compared with 13 of 21 (62%) outborn infants. An antenatal diagnosis before 25 weeks' gestation was associated with a 60% survival rate. Sixty-three percent of infants whose best postductal PaO2 value before ECMO was less than 100 torr survived, and 7 of 11 infants with a best postductal PaO2 value of less than 50 torr before ECMO survived (64%). The average age at surgery progressively increased over time both for infants who did not require ECMO (1.3 days to 5.8 days; P = .01) and for infants who received ECMO (1.9 days to 8.2 days; P = .016).

CONCLUSIONS

The use of a protocolized management for infants with CDH has been associated with improving outcome in a population at high risk. The components (either separately or combined) of these protocolized approaches need to be tested in prospective trials to determine their true benefit. In addition, there is a need to evaluate prospectively the outcomes of infants with CDH born in ECMO centers compared with those infants born in other tertiary care neonatal units to determine the most appropriate management of the fetus with CDH.

Correction of congenital diaphragmatic hernia in utero VII: a prospective trial

BACKGROUND

Congenital diaphragmatic hernia (CDH) remains an unsolved problem. Despite optimal postnatal care, up to 60% of CDH babies die. Experimental evidence and clinical experience have shown that in utero repair of CDH is feasible and can reverse pulmonary hypoplasia, but only in fetuses without liver herniation. For this subgroup, the safety and efficacy of repair before birth has not been compared with standard care after birth.

METHODS

Four fetuses in whom CDH without liver herniation was diagnosed underwent open fetal surgery for repair of the CDH. Seven comparison fetuses were treated conventionally. Neonatal mortality was the principle outcome variable. Secondary outcome variables included death of all causes until 2 years of age, number of days of ventilatory support, length of hospital stay, requirement for extracorporeal membrane oxygenation (ECMO), and total hospital charges.

RESULTS

There was no difference in survival between the fetal surgery group and the postnatally treated comparison group (75% v 86%). Fetal surgery patients were born more prematurely than the comparison group (32 weeks v 38 weeks' gestation). Length of ventilatory support and requirement for ECMO were equivalent in the fetal surgery group and the postnatally treated comparison group. Length of hospital stay and hospital charges did not differ between the groups.

CONCLUSIONS

Open fetal surgery is physiologically sound and technically feasible, but does not improve survival over standard postnatal treatment in the subgroup of CDH fetuses without liver herniation, primarily because overall survival in this subgroup is favorable with or without prenatal intervention. These data suggest that fetuses who have prenatally diagnosed CDH and without evidence of liver herniation should be treated postnatally.

Cardiac arrest before repair or extracorporeal membrane oxygenation cannulation does not increase the mortality rate associated with congenital diaphragmatic hernia

Despite recent advances in the management of high-risk congenital diaphragmatic hernia (CDH), mortality remains high. Deaths occur later because infants with inadequate pulmonary parenchyma are treated aggressively but eventually succumb to respiratory failure. In an attempt to identify absolute predictors of mortality the authors examined retrospectively their experience with CDH to determine if cardiac arrest before repair or initiation of extracorporeal membrane oxygenation (ECMO) invariably increased mortality. The authors reviewed the charts of 119 infants who had high-risk CDH treated between 1981 and 1994. They were divided into two groups: those that suffered cardiopulmonary arrest (CA, n = 21) before CDH repair or ECMO cannulation; and those that did not (NCA, N = 98). The authors compared mortality rate, ventilatory parameters, duration of, and complications on ECMO, as well as length of hospitalization between groups. Twenty-one infants suffered CA before initiation of ECMO support or CDH repair. Three infants (14%) suffered CA before arrival at our institution; seven (33%) after, and 11 (53%) both before and after arrival. There was no difference between the CA and NCA groups in terms of birth weight, gestational age, race and gender mix, or pregnancy and delivery complications. Five-minute Apgar scores were significantly lower in the CA group compared with the NCA group (4.6 v 5.7, P = .04). The CA group also had significantly worse "best postductal" blood gas and ventilatory parameters. There was no significant difference in length of hospitalization, time from admission to ECMO cannulation or CDH repair, or incidence of complications while on ECMO between the two groups. CA cases were more likely to require ECMO support (76% v 48%, P = .02) and to stay on ECMO for a more prolonged period than NCA cases (5.8 v 3.8 days, P = NS). However, there was no significant difference in overall survival between CA and NCA cases (43% v 51%, P = NS). Cardiopulmonary arrest before repair of CDH or ECMO cannulation is not a univariate independent predictor of mortality and therefore should not preclude these high-risk infants from maximum intensive care therapy, including ECMO cannulation.

Does extracorporeal membrane oxygenation benefit neonates with congenital diaphragmatic hernia? Application of a predictive equation

The overall survival of neonates with congenital diaphragmatic hernia (CDH) remains poor despite the advent of extracorporeal membrane oxygenation (ECMO). Attempts at accurately predicting survival have been largely unsuccessful. The purpose of this study was twofold: (1) to identify independent predictors of survival from a cohort of CDH neonates treated at the authors' institution when ECMO was not available and combine them to form a predictive equation, and (2) to apply the equation prospectively in a cohort of CDH neonates, treated at the same institution when ECMO was available, to determine whether ECMO improves outcome. From the clinical data of 62 CDH neonates treated at the authors' center by the same team of university neonatologists and pediatric surgeons between 1983 and 1993 (before ECMO availability), 15 preoperative and seven operative variables were selected as potential independent predictors. When subjected to multivariate, stepwise logistic regression analysis, four variables were identified as statistically significant (P < .05), independent predictors of survival: (1) ventilatory index (VI), (2) best preoperative PaCO2, (3) birth weight (BW), and (4) Apgar score at 5 minutes. When combined via logistic regression analysis, the following predictive equation was formulated: P (probability of survival to discharge) = [1 + e(x)]-1 where x = 4.9 - 0.68 (Apgar) - 0.0032 (BW) + 0.0063 (VI) + 0.063 (PaCO2). Applying a standard cut-off rate of survival at less than 20%, the equation yielded a sensitivity of 94% and a specificity of 82% in identifying the correct outcome of patients treated with conventional ventilatory management. The overall survival rate was 66%. Since the availability of ECMO at the center, 32 CDH neonates were treated using the same conventional ventilatory treatment and surgical repair by the same university staff. The overall survival rate was 69%. The predictive equation was applied prospectively to all neonates to determine predicted outcome, but was not used to decide the treatment method. Eighteen neonates received conventional therapy alone; 16 of 18 survived (89%). Fifteen of the 16 patients who survived had their outcomes predicted correctly (94%). Fourteen neonates did not respond to conventional therapy and required ECMO; 6 of 14 survived (43%). Six of the eight patients predicted to survive, lived (75%). All six patients predicted to die, died despite the addition of ECMO therapy (100%). The mean hospital cost, per ECMO patient who died, was $277,264.75 +/- $59,500.71 (SE). An odds ratio analysis, using the four independent predictors to standardize for degree of illness, was performed to assess the risk associated with adding ECMO therapy. The result was 1.25 (P = 0.75). Although the cohort was not large enough to eliminate significant beta error, the data strongly suggested no advantage of ECMO. At this center, absolute survival rates for neonates with CDH have not been significantly altered since ECMO has become available (66% v 69%). The authors conclude that the predictive equation remains an accurate measurement of survival at their center even when ECMO is used as a salvage therapy. The method of creating a predictive equation may be applied at any institution to determine the potential outcome of CDH neonates and assess the effect of ECMO, or other salvage therapies, on survival rates.

Congenital diaphragmatic hernia--a tale of two cities: the Boston experience

Infants with congenital diaphragmatic hernia (CDH) show a wide range of anatomic and physiological abnormalities, making it difficult to compare the efficacy of management protocols between institutions. The purpose of this study was twofold: (1) to analyze the results of treatment of CDH in a large tertiary care pediatric center using conventional mechanical ventilation (CMV) with extracorporeal membrane oxygenation (ECMO) as rescue therapy, and (2) to compare these results with those of a parallel study by a similar large urban center that used high-frequency oscillating ventilation (HFOV) as rescue therapy without ECMO. All patients who had CDH diagnosed within the first 12 hours of life and were referred for treatment before repair (between 1981 and 1994) were included in the analysis (n = 196). CMV was used initially in all patients, with conversion to ECMO for refractory hypoxemia or hypercapnea. Between 1981 and 1984, ECMO was not available. Between 1984 and 1987, ECMO was offered postoperatively. Between 1987 and 1991, ECMO was offered preoperatively. In all three groups, aggressive hyperventilation and alkalosis was the norm. Since 1991, permissive hypercapnia has been used. HFOV was used in three patients as stand-alone therapy with one survivor. Twenty patients died without repair: Ten had other lethal anomalies, eight died before ECMO could be instituted, and two died of ECMO-related complications. Overall, 104 patients (53%) survived and 92 (47%) died. Ninety-eight patients (50%) received ECMO, and 43 (44%) survived. Survivors had significantly higher 1- and 5-minute Apgar scores and higher postductal Po2s than did nonsurvivors. Associated anomalies were present in 39%, who had a significantly lower survival than those with isolated CDH. Antenatal diagnosis and side of the defect had no impact on outcome. Survival was not improved with the institution of ECMO or delayed repair but rose significantly to 69% (84% with isolated CDH, P = .007) with the introduction of permissive hypercapnea. Autopsy results from nonsurvivors showed other lethal anomalies and significant barotrauma as the primary causes of death. Comparisons between the Boston and Toronto series showed similar patient demographics and no significant differences in survival in any time period. The two series differed in the number of associated anomalies, their impact on survival, and in the prognosis of right-sided CDH. From the individual and combined analyses the authors concluded: (1) CMV with ECMO as rescue produced an overall survival in CDH patients equivalent to CMV with HFOV in a parallel series, (2) neither HFOV nor ECMO has significantly improved outcome in CDH patients, (3) institution of permissive hypercapnia has resulted in a significant increase in survival, and (4) the leading causes of death in CDH patients appear to be associated anomalies and pulmonary hypoplasia, which are currently untreatable. Barotrauma, which may contribute in up to 25% of deaths in CDH patients is avoidable.

Congenital diaphragmatic hernia--a tale of two cities: the Toronto experience

PURPOSE

The optimal therapy for congenital diaphragmatic hernia (CDH) is evolving. This study analyzes the results of treatment of CDH in a large tertiary care pediatric center using conventional and high-frequency oscillatory ventilation (HFOV) without extracorporeal membrane oxygenation (ECMO) contrasting these with a parallel study from a similar large urban center using conventional ventilation with ECMO.

METHODS

Between 1981 and 1994, 223 consecutive neonates who had CDH diagnosed in the first 12 hours of life were referred for treatment before repair. Conventional ventilation was used with conversion to HFOV for refractory hypoxemia or hypercapnia, and a predicted near 100% mortality rate. ECMO was used in only three patients, all of whom died. A retrospective database was collected. Thirty-one clinical variables were tested for their association with the outcome. Common ventilatory and oxygenation indices were tested for their prognostic capability.

RESULTS

Apgar scores, birth weight, right-sided defects, pneumothorax, total ventilatory time, and the use of high frequency oscillatory ventilation were the only variables associated with outcome. A modified ventilatory index and postductal A-aDo2 were strong prognostic indicators. From 1981 to 1984 surgery was performed on an emergency basis. Since 1985 surgery was deferred until stabilization had been achieved. This resulted in a shift in the mortality from postoperative to preoperative with no change in total survival. HFOV did not alter the overall survival. Results of autopsies performed (70%) showed significant pulmonary hypoplasia and barotrauma as the primary causes of death. The survival was 54.7%.

CONCLUSION

Conventional ventilation with HFOV produced equal survival to conventional ventilation with ECMO in two comparable series. Pulmonary hypoplasia was the principle cause of death. This continued high mortality at both centers suggests that new therapies are required to improve outcomes.

Can blood gas values predict pulmonary hypoplasia in antenatally diagnosed congenital diaphragmatic hernia?

The prognosis of antenatally diagnosed congenital diaphragmatic hernias (CDH) is clearly related to the degree of pulmonary hypoplasia (PH). After birth, controversies remain regarding the implementation of various therapies, especially the use of extracorporeal membrane oxygenation (ECMO). In the literature, the persistence of a Pao2 below 100 mm Hg and of Paco2 above 40 mm Hg despite optimal conventional therapy indicates poor prognosis. Therefore, since 1992, published and personal experiences led the authors to exclude CDH patients from ECMO when conventional therapy (including high-frequency oscillatory ventilation and nitric oxide) did not obtain Pao2 of above 80 mm Hg and Paco2 of below 60 mm Hg. The aim of this retrospective study is to determine whether blood gas results correlate with postmortem findings. Between July 1990 and July 1994, 32 cases of CDH were monitored antenatally and managed postnatally at the authors' institution. Six patients survived; 26 died, including one immediately at birth. Thirteen were treated by ECMO. Seventeen had a best Pao2 of above 80 mm Hg, including the six survivors. Fourteen did not reach this level, and none of them survived. Twenty-three infants underwent postmortem examination. PH was assessed using two criteria: (1) lung weight to body weight ratio (LW/BW) and (2) radial alveolar count (RAC). Two patients did not have hypoplasia (LW/BW > 0.018). Twenty-one patients had PH; 12 of them had an LW/BW ratio of less than .009; for 9, the LW/BW ratio was between .009 and .018, and the RAC (< 3.1) confirmed PH. All infants with a best Pao2 of less than 80 mm Hg had PH. Patients with a best Pao2 of greater than 80 mm Hg included two infants who died from complications without PH, eight infants with demonstrated PH, and the six survivors. In conclusion. (1) No infant with nonhypoplastic lungs has been deprived of ECMO by the authors' criteria. (2) Adequate values of blood gases may not eliminate PH. Therefore, this probably justifies starting ECMO when conventional therapy fails. (3) Conversely, permanent poor values of Pao2 allowed the prediction of PH in all cases. Such patients probably can be excluded from ECMO treatment.

How often is extracorporeal membrane oxygenation needed in cases of congenital diaphragmatic hernia?

Some newborns with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension cannot be saved by conventional treatment and may obtain some benefit from extracorporeal membrane oxygenation (ECMO) as a bridging measure until adequate hematosis is possible. Early prediction of the insufficiency of "optimal" assistance is still unclear; we reviewed our recent experience with CDH patients in an attempt to evaluate the real need for ECMO in our institution. Between 1987 and 1994, 47 newborns with CDH manifested in the first 24 h were treated with maximal ventilatory assistance (including high-frequency ventilation in 12 cases) and vasoactive drugs prior to surgical repair. In order to summarize the ventilatory and blood-gas parameters, we determined oxygenation index (OI) and ventilatory index (VI) and compared the results in survivors and nonsurvivors. Overall survival was 60% (2 cases of Fryns' syndrome were excluded from analysis). OI was 10.3±5.7 (mean ± SD) for survivors and 46.2 ± 37.8 for nonsurvivors (P < 0.01). VI was 460.9±303 and 1,532±500.6, respectively (P <0.01). Bayesian analysis and receiver operating characteristic curves enabled us to select a threshold value of OI of 20 as the best means of predicting survival in our current conditions (sensitivity: 0.7, specificity: 0.83). The generally accepted figure of 40 had a sensitivity of 1 but a specificity of only 0.44. For VI, the best threshold value was 1,100 (sensitivity: 0.93, specificity: 0.94), whereas the generally used figure of 1,000 had 0.89 and 1, respectively. According to our results, with our current management conditions, approximately 50% of our CDH patients might have obtained some benefit from ECMO.

Prenatal glucocorticoid therapy reverses pulmonary immaturity in congenital diaphragmatic hernia in fetal sheep

OBJECTIVE

To assess the feasibility of conducting clinical trials of prenatal steroid therapy for congenital diaphragmatic hernia (CDH) in humans, the authors tested whether prenatal glucocorticoid, currently the standard treatment to minimize respiratory distress syndrome in premature infants, might improve the pulmonary immaturity in severe CDH in a large animal model.

SUMMARY BACKGROUND DATA

The authors have used the nitrofen-induced rat model of CDH, which demonstrates immature lungs by biochemical, morphometric, and molecular biologic criteria. They also have shown that the lethally immature lungs of the full-term CDH rats can be improved by biochemical, morphometric, physiologic, and molecular criteria by treating the mothers with parenteral steroids at doses extrapolated from the current therapy used to accelerate lung development of premature human babies.

METHODS

During a 3-year period in 88 fetal sheep, 1) left-sided diaphragmatic hernias were created surgically at varying gestational ages (day 78-90; term = 142-145 days) and size to maximize severity (n = 45), 2) placement and design of indwelling fetal intravenous catheters were optimized (n = 13), and 3) timing and dosage of cortisol administration were determined (n = 17). As a result, diaphragmatic hernias were created on day 80, intravenous catheters were placed on day 120, and twice-daily intravenous cortisol injections (n = 8) or saline as the control (n = 5) were administered (days 133-135). Lambs were delivered on day 136 via cesarean section to avoid steroid-induced abortion; vascular access was obtained, and the fetuses were ventilated at standard settings. Physiologic data were collected, and lungs were harvested for biochemical and histologic analysis.

RESULTS

Significant improvements were measured in postductal arterial oxygen pressure ([PaO2] 38 +/- 6 mmHg after cortisol therapy compared with 20 +/- 3 mmHg for saline controls; p = 0.002) and in dynamic compliance (0.42 +/- 0.05 mL/cm H2O vs. 0.29 +/- 0.01 mL/cm H2O; p = 0.01). Lung glycogen levels in the right lung of the cortisol group were significantly better than controls (4.6 +/- 0.3 mg/g lung vs. 6.8 +/- 0.4 mg/g; p = 0.002), as were protein/DNA levels (8.3 +/- 0.9 mg/mg vs. 14.5 +/- mg/mg; p < 0.05). Striking morphologic maturation of airway architecture was observed in the treated lungs.

CONCLUSIONS

Prenatal glucocorticoids correct the pulmonary immaturity of fetal sheep with CDH by physiologic, biochemical, and histologic criteria. These data, combined with previous small animal studies, have prompted the authors to initiate a prospective phase I/II clinical trial to examine the efficacy of prenatal glucocorticoids to improve the maturation of hypoplastic lungs associated with CDH.

Congenital diaphragmatic hernia: lung compliance after antenatal tracheal obstruction or surgical correction of the defect

Fetal lambs with diaphragmatic herniae (CDH) created surgically at 73 days' gestation were subjected to three different forms of intrauterine correction: silastic patch correction of the diaphragmatic defect plus an abdominal patch at 101 days gestation; an intrathoracic "silo" at 101 days; and a tracheal "plug" obstruction at 101 or 129 days. At 143 days' gestation (term 145-149 days), the lambs were delivered by caesarean section and ventilated for 30 min before undergoing respiratory compliance measurements. These results were compared to those of normal lambs and animals with uncorrected herniae. The total respiratory system compliance values in those groups undergoing corrections were remarkably similar: those with any form of correction had a significant improvement (P < 0.05) compared to those with herniae and no correction (patch = 1.57 = ± 0.182 ml/cm H2O; silo = 1.53 ± 0.179; plug at 101 days = 1.66 ± 0.311; plug at 129 days = 2.00 ± 0,175; without correction = 0.62 ± 0.073). None, however, reached the values of those with normal lungs: 2.72 ± 0.223 (P < 0.05). This improvement in compliance in all corrected groups suggests that fetal tracheal obstruction is as effective as the two more invasive forms of open fetal surgery carried out in this study and, as this procedure lends itself to surgery through a small uterine incision or "minimally invasive" surgery, it may be the procedure of choice to reduce the incidence of preterm labour for those human fetuses undergoing antenatal correction of a CDH.bb.

Real and apparent mortality from congenital diaphragmatic hernia

Some 50 cases of congenital diaphragmatic hernia (CDH) born in the authors' regional referral area over the 14 years from 1980 to 1993 were reviewed, contrasting 7 years when management included preoperative ventilatory stabilization with the preceding 7 when urgent surgery was performed. Six children experienced no respiratory distress and suffered no mortality. For infants with respiratory distress in the first 6 h of life, ventilatory stabilization improved survival rates of those who reached the surgical centre from 45 per cent between 1980 and 1986 to 59 per cent between 1987 and 1993. A larger proportion of the total number of patients, however, continued to die without reaching the surgical centre. The improvement in survival rate based on the true incidence of CDH was from 28 per cent in the first period to 38 per cent in the second. The apparent poor survival rate of patients born in central obstetric units compared with those born in peripheral units (37 versus 75 per cent) can be attributed to patient selection; a larger number of children born in central units were transferred for surgery (70 versus 57 per cent). There is no evidence that paediatricians have altered their referral practice to include prolonged ventilation outside the surgical unit since delayed surgery was advocated. Assessment of the impact of altering the management of CDH cannot be made without knowing the number of patients who die before transfer to a neonatal surgical unit. Any serious attempt to reduce the mortality rate of CDH must be directed to neonates who are not presently referred to the surgical service.

Congenital diaphragmatic hernia: experience in a single institution from 1978 through 1994

BACKGROUND

Congenital diaphragmatic hernia continues to be a difficult management problem. Essentially all information on the condition has been compiled in a retrospective manner due to the individualized care that each infant must undergo. We contribute a review of our patients to add to the current fund of knowledge and to assess our experience before and since the introduction of extracorporeal membrane oxygenation in our institution.

METHODS

This is a review of records of infants with congenital diaphragmatic hernia treated from 1978 through 1994. Repair has generally been accomplished early with only one repair being accomplished with an infant placed on extracorporeal membrane oxygenation preoperatively.

RESULTS

Overall survival was 63%. Survival was 42% before extracorporeal membrane oxygenation becoming available in our region in 1986, and 75% afterward. Since 1986, 16 of 33 (48%) infants have required extracorporeal membrane oxygenation and 73% have survived.

CONCLUSIONS

Overall survival in our series is comparable with that of other reported series. There appears to be an improvement in survival since the introduction of extracorporeal membrane oxygenation. Our present practice of early repair, and postrepair extracorporeal membrane oxygenation if needed, results in a survival rate comparable with that of currently available series reports regardless of the method of treatment reported.

Improving survival for patients with high-risk congenital diaphragmatic hernia by using extracorporeal membrane oxygenation

The benefit of extracorporeal membrane oxygenation (ECMO) in cases of high-risk congenital diaphragmatic hernia (CDH) was studied by comparing pre-ECMO (1987-1990) and post-ECMO (1991-1994) 3-month survival statistics. Fifty-five CDH patients who presented in respiratory distress within 6 hours after birth were referred--18 in the pre-ECMO era and 37 in the ECMO era. During the entire study period (December 1987 through July 1994) the patients were treated by the same protocol of preoperative stabilization and delayed surgery; the only difference was the addition of ECMO beginning in January 1991. The patients were stratified based on the response to conventional treatment: 1, no response (irretrievable); 2, stable; 3, unstable. The 3-month survival rate for the unstable neonates (who could not be stabilized by conventional therapy) improved from 0% (0 of 9) in the pre-ECMO era to 61% (11 of 18) in the ECMO era (P = .004). This highly significant difference shows that ECMO is a very valuable addition to the management of high-risk CDH patients whose conditions remain unstable despite maximal conventional therapy.

Survival in neonatal congenital hernia without extracorporeal membrane oxygenation support

The experience with high-risk congenital diaphragmatic hernia (CDH) at an institution that does not offer extracorporeal membrane oxygenation (ECMO) was reviewed. Between January 1, 1983 and December 31, 1993, 38 children presented with Bochdalek-type CDH. Excluded were two infants with lethal cardiac anomalies and four presenting after 4 hours of age. Thus, the authors identified 32 high-risk patients. All had early respiratory distress and were intubated within 5 hours of birth. Sixteen were inborn; 16 were referred to the Izaak Walton Killam Children's Hospital (IWK) within 24 hours of birth. There were 19 males and 13 females. Three died before surgery could be attempted. Twenty-two survived, giving an overall survival rate of 69% (22 of 32). For 28 of the 32, the best preoperative postductal Pao2 (BPDPao2) was recorded. Fifteen of the 28 children had a BPDPao2 of greater than 100 mm Hg. Survival in this group was 14 of 15 (93%). Thirteen of the 28 patients had a BPDPao2 of less than 100 mm Hg. Survival in this group was 5 of 13 (38%). These survival rates are comparable to those of centers offering ECMO. BPDPao2 appears to be a useful discriminating variable.

Nucleated erythrocyte count in newborn infants with left-sided congenital diaphragmatic hernia: relationship with the need for extracorporeal membrane oxygenation and survival

Inadequate cardiac output in fetuses with left-sided congenital diaphragmatic hernia may cause chronic hypoxia and increased erythropoiesis. Postnatal nucleated erythrocyte counts were measured in 28 newborn infants with left-sided congenital diaphragmatic hernia who were eligible for extracorporeal membrane oxygenation (ECMO). Nucleated erythrocyte counts were lowest in infants who survived without ECMO, intermediate in survivors requiring ECMO, and highest in infants who died despite ECMO.

Respiratory deadspace measurements in neonates with congenital diaphragmatic hernia

OBJECTIVE

To apply the technique of respiratory deadspace measurement to consecutive infants with congenital diaphragmatic hernia, who were referred to our institution, in order to assess the efficiency of gas exchange.

DESIGN

A cohort study evaluating the utility of deadspace measurements in neonates with congenital diaphragmatic hernia.

SETTING

Tertiary care pediatric intensive care unit in a university hospital.

PATIENTS

Thirty infants with congenital diaphragmatic hernia were studied on presentation to our institution, either before the institution of extracorporeal membrane oxygenation (ECMO) or after stabilization on ECMO.

METHODS

The CO2 concentration of expired gas sampled at the exhaust port of the test ventilator was continuously measured and transformed to mixed expired CO2 by the following formula that corrects for compressible volume measured by the ventilatory pneumotachometer: mixed expired CO2 = (PCO2 in exhaust gas) x (ventilatory pneumotachometer minute volume)/(minute volume at the proximal airway). We then utilized the Bohr-Enghoff method to calculate the deadspace/tidal volume ratio: deadspace/tidal volume ratio = (PaCO2 - mixed expired PCO2)/PaCO2.

MEASUREMENTS AND MAIN RESULTS

Deadspace/tidal volume ratio was calculated either before the institution of ECMO or during temporary separation from ECMO support as the patients demonstrated improvements in gas exchange and lung compliance. One hundred two measurements were made in 30 patients, with a mean of four measurements per patient (range 1 to 10). There was a significant (p = .005) difference between the first deadspace/tidal volume ratio measured, in survivors vs. nonsurvivors. The mean of the highest deadspace/tidal volume ratio in survivors was 0.47 compared with 0.62 in nonsurvivors (p = .003). A deadspace/tidal volume ratio of > or = 0.60 predicted mortality, with a positive predictive value of 80%, a negative predictive value of 79%, and an odds ratio of 15. The mean pre-ECMO deadspace/tidal volume ratio in those infants who ultimately required ECMO was significantly greater than the mean value for infants not requiring ECMO (0.65 vs. 0.43; p = .004). In patients who were treated with ECMO, survivors demonstrated a significant decrease in deadspace/tidal volume ratio during the course of ECMO. This decrease was not seen in the ECMO-treated patients who did not survive.

CONCLUSIONS

Predictors of outcome in infants with congenital diaphragmatic hernia have been complicated and contradictory, particularly in the ECMO era. We demonstrated that the respiratory deadspace can be easily quantified in these infants, and that a physiologic deadspace of > 0.60 is associated with a 15-fold increase in mortality rate. We also demonstrated that in those infants treated with ECMO, the survivors manifested a significant decrease in their deadspace/tidal volume ratio before ECMO decannulation.

Experience with abdominal wall closure for patients with congenital diaphragmatic hernia repaired on ECMO

Congenital diaphragmatic hernia (CDH) and its attendant lack of abdominal domain can create major technical challenges with respect to diaphragmatic and abdominal wall reconstruction, especially in seriously ill infants who require extracorporeal membrane oxygenation (ECMO). The authors reviewed the medical records of all infants with CDH repaired on ECMO at their institution (group 1, 15 patients), and compared them with infants having CDH repair before ECMO (group 2, 20 patients) and with those who had CDH repair but did not require ECMO (group 3, 15 patients). Thirty-seven of 50 patients survived (74%): 10 in group 1, 12 in group 2, and all 15 in group 3. There was a statistically significant difference (P < .001) with respect to the requirement of a polytetrafluoroethylene (PTFE) diaphragmatic patch for patients in group 1 versus those in both groups 2 and 3. There was also a significant difference in the number of patients in whom the abdomen could not be closed (P < .001 for group 1 v groups 2 and 3). Infants who require ECMO before CDH repair are more likely to have large diaphragmatic defects that require prosthetic reconstruction, and abdominal wall closure problems resulting from loss of abdominal domain, which further complicate the management of the physiological derangements from pulmonary hypoplasia and persistent pulmonary hypertension.

Predictors of survival for infants with congenital diaphragmatic hernia

Over the past decade, the survival rate of infants with congenital diaphragmatic hernia (CDH) treated in the intensive care unit of the Royal Children's Hospital, Melbourne, has remained unchanged at 56% +/- 6%. Newer forms of treatment, such as extracorporeal membrane oxygenation (ECMO), high-frequency oscillation, and surfactant and nitric oxide therapy, are now available. The exact role of these therapies in the management of infants with CDH has not been determined. This study examines five clinical parameters derived from an infant's best preoperative ventilatory and blood gas data in the first 24 hours of life. One hundred twenty-five CDH infants were admitted to the intensive care unit between January 1, 1981 and December 31, 1991. Criteria for inclusion in the study were (1) CDH diagnosed within 6 hours of delivery, (2) ventilation before repair, and (3) no associated lethal congenital abnormality. Of the 90 cases studied in detail, there were 38 deaths (42% mortality rate). All five parameters were analyzed by receiver operating curve analysis to determine the optimum value of each parameter in predicting survival. An oxygenation index (MAP x FIO2/PaO2) of less than 0.08 predicted a 94% chance of survival, with a sensitivity of 96% and a specificity of 95%. Similarly, a modified ventilation index (PIP x RR x CO2/1,000) of less than 40 predicted a 91% chance of survival, with a sensitivity of 94% and a specificity of 86%. By stratifying each criterion according to outcome, three groups of infants were identified according to their response to conventional therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of left ventricular mass in children with left-sided congenital diaphragmatic hernia

To evaluate left ventricular (LV) mass in children with left-sided congenital diaphragmatic hernia (CDH), we retrospectively examined the echocardiographic data available on all newborn infants with a diagnosis of CDH between April 1989 and May 1993. Adequate data for evaluation were available for 20 of 31 patients with left-sided CDH and no significant congenital heart disease. Left ventricular mass was determined from two-dimensional echocardiograms by an area-length method. Findings were compared with a control group that consisted of neonates with other causes of pulmonary hypertension. Patients with left-sided CDH had a significantly lower indexed LV mass than control subjects (1.96 gm/kg +/- 0.59 vs 2.84 gm/kg +/- 0.41; p = 0.0001). Additionally, children with left-sided CDH who required extracorporeal membrane oxygenation before repair (n = 7) had a significantly lower indexed LV mass than those patients who did not require extracorporeal membrane oxygenation before repair (1.53 gm/kg +/- 0.50 vs 2.20 gm/kg +/- 0.52; (p = 0.007). Infants who survived (n = 13) had an indexed LV mass of 2.09 gm/kg +/- 0.58 vs 1.64 gm/kg +/- 0.58 in those who died (p = 0.07). We conclude that the LV mass index in children with left-sided CDH is significantly lower than in children with other causes of pulmonary hypertension in the newborn period. Evaluation of LV mass in neonates with left-sided CDH may help predict the need for extracorporeal support before surgical repair, and may help indicate overall prognosis.

Congenital diaphragmatic hernia and associated anomalies: their incidence, identification, and impact on prognosis

The general concept of the association of congenital diaphragmatic hernia (CDH) with other anomalies has been well described. This study is aimed at assessing the distribution of the associated anomalies (AA) by organ system, their influence on prognosis, and the practical signs that should prompt a diagnostic search. One hundred and sixty-six high-risk patients with CDH (symptomatic within the first 6 hours of life) were treated in this institution in the past decade. Sixty-five patients (39.2%) were found to have one or more AA, and 101 had isolated CDH. Of patients with anomalies, cardiac (excluding patent foramen ovale and patent ductus arteriosus) was the most frequent type of AA (63%). Hypoplastic heart syndrome was the most common defect. Many patients had multiple AA. For purposes of analysis, the patients were divided into three groups: isolated CDH, cardiac anomalies, and all other anomalies. The groups were compared with respect to several common clinical and laboratory variables, as well as survival. The frequency and timing of antenatal diagnosis were also noted. The analysis led to the following conclusions. (1) AA are present in more than one third of high-risk patients with CDH; in this group, cardiac lesions predominate. (2) High-risk CDH infants with AA have significantly lower APGAR scores and a lower BPDPO2 (best postductal PO2 before ECMO or surgery) than those with isolated CDH. This is even more evident in the group with cardiac AA. In such patients, a careful search for an undetected AA, especially cardiac, is warranted.(ABSTRACT TRUNCATED AT 250 WORDS)

Complications of neonatal extracorporeal membrane oxygenation

From 1973-1985 to 1988 the average patient complications per case were 1.44 per case and significantly increased during 1990 to 1992 to 2.10 per case (Figure 3). During the same periods patient survival significantly decreased from 84% (1973-1985 to 1988, n = 2463) to 80% (1990 to 1992, n = 4005) (Figure 4). The association between total complication rates and survival rate was examined by regression analysis (Table 5). The correlation of patient complication rate and total complication rate with survival is highly significant; however, causality cannot be established. When comparing different entry criteria (Table 2) for incidence of mechanical and patient complications, no significant differences are apparent. This is not surprising since each of the entry criteria were designed to identify the same patient population. When premature neonates (> 35 weeks) were placed on ECMO, 36% of them had intracranial haemorrhage (ICH) with 62% mortality while only 12% of the neonates < 35 weeks had ICH and a 49% mortality. Similar findings were noted with low birthweight neonates (< 2.2 kg), 28% had ICH with 64% mortality while only 12% of the neonates > 2.2 kg had ICH with a 50% mortality. Selection criteria remain problematic for a variety of reasons. They cannot be viewed as absolute because of variability between centres. What represents likely 80% mortality in one centre may not apply to another. Historical controls are misleading because changing respiratory therapy strategies make historical populations difficult to compare. Also, once an ECMO centre becomes established, a more challenging group of patients will be attracted than previously was the case. Further, a single entry criterion cannot be generalized for all entry diagnoses. Criteria for an 80% predicted mortality is probably not the same for MAS, CHN, PPHN, and sepsis. Subsequent patients registered in the Neonatal ECMO Registry of the Extracorporeal Life Support Organization will address these issues more thoroughly, as specific details of the pre-ECMO condition and therapeutic strategies are collected. This collective review should help to identify trends which require reassessment of technique or patient management.

Congenital diaphragmatic hernia treated by perinatal stabilization

The delay of surgery in conjunction with high-frequency oscillation ventilation combined with preoperative stabilization is a standard treatment for congenital diaphragmatic hernia neonates in the high-risk group. A new protocol of perinatal stabilization with this preoperative stabilization has been developed at the University of Tokyo Hospital. The most important components of this method of perinatal stabilization are cesarean section and the injection of morphine and pancuronium through the umbilical vein prior to ligation of the umbilical cord. In order to benefit from this treatment, congenital diaphragmatic hernia patients should be diagnosed antenatally by ultrasonography and be delivered by cesarean section. This protocol of perinatal stabilization appears effective in congenital diaphragmatic hernia patients.

Usefulness of echocardiographic measurement of bilateral pulmonary artery dimensions in congenital diaphragmatic hernia

In nine patients with left-sided congenital diaphragmatic hernia (CDH) developing within 24 hours of birth, the authors measured the dimensions of the bilateral main pulmonary arteries by echocardiography, and investigated whether the left:right main pulmonary artery dimension ratio (PAD ratio) was a useful index for predicting pulmonary hypoplasia and persistent fetal circulation (PFC). Echocardiography was performed shortly after admission, the PAD ratio was calculated, and the clinical course of each patient was determined. When the PAD ratio was approximately 1.0, patients did not suffer from PFC and had little evidence of pulmonary hypoplasia. When the PAD ratio was low, the patients suffered from PFC and had pulmonary hypoplasia on the side of the hernia. Thus, the PAD ratio measured by echocardiography appears to be a useful index for predicting pulmonary hypoplasia and the risk of PFC in patients with CDH.

Newborn surgical emergencies. Congenital diaphragmatic hernia and extracorporeal membrane oxygenation

Bochdalek hernia is a posterolateral defect in the embryogenesis of the diaphragm. Abdominal contents enter the thorax during fetal development and result in pulmonary hypoplasia. A cause of respiratory distress in the newborn, the management of this disease has undergone dramatic changes. The defect requires surgical repair, but success depends more on preoperative and postoperative management of the associated physiologic derangements.