Delayed repair and preoperative ECMO does not improve survival in high-risk congenital diaphragmatic hernia

The role of extracorporeal life support and timing of repair in infants with congenital diaphragmatic hernia

Extracorporeal life support (ECLS) serves as a rescue therapy for patients with congenital diaphragmatic hernia (CDH) and severe cardiopulmonary failure, and only half of these patients survive to discharge. This costly intervention has a significant complication risk and is reserved for patients with the most severe disease physiology refractory to maximal cardiopulmonary support. Some contraindications to ECLS do exist such as coagulopathy, lethal chromosomal or congenital anomaly, very preterm birth, or very low birth weight, but many of these limits are being evaluated through further research. Consensus guidelines from the past decade vary in recommendations for ECLS use in patients with CDH but this therapy appears to have a survival benefit in the most severe subset of patients. Improved outcomes have been observed for patients treated at high-volume centers. This review details the evolving literature surrounding management paradigms for timing of CDH repair for patients receiving preoperative ECLS. Most recent data support early repair following cannulation to avoid non-repair which is uniformly fatal in this population. Longer ECLS runs are associated with decreased survival, and patient physiology should guide ECLS weaning and eventual decannulation rather than limiting patients to arbitrary run lengths. Standardization of care across centers is a major focus to limit unnecessary costs and improve short-term and long-term outcomes for these complex patients.

Impact of Time Point of Extracorporeal Membrane Oxygenation on Mortality and Morbidity in Congenital Diaphragmatic Hernia: A Single-Center Case Series

Since there are no data available on the influence of the time point of ECMO initiation on morbidity and mortality in patients with congenital diaphragmatic hernia (CDH), we investigated whether early initiation of ECMO after birth is associated with a beneficial outcome in severe forms of CDH. All neonates with CDH admitted to our institution between 2010 until 2020 and undergoing ECMO treatment were included in this study and divided into four different groups: (1) ECMO initiation < 12 h after birth (n = 143), (2) ECMO initiation between 12−24 h after birth (n = 31), (3) ECMO initiation between 24−120 h after birth (n = 48) and (4) ECMO initiation > 120 h after birth (n = 14). The mortality rate in the first (34%) and fourth group (43%) was high and in the second group (23%) and third group (12%) rather low. The morbidity, characterized by chronic lung disease (CLD), did not differ significantly in the three groups; only patients in which ECMO was initiated >120 h after birth had an increased rate of severe CLD. Our data, although not randomized and limited due to small study groups, suggest that very early need for ECMO and ECMO initiation > 120 h after birth is associated with increased mortality.

Clinical guidelines for the treatment of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a birth defect of the diaphragm in which abdominal organs herniate through the defect into the thoracic cavity. The main pathophysiology is respiratory distress and persistent pulmonary hypertension because of pulmonary hypoplasia caused by compression of the elevated organs. Recent progress in prenatal diagnosis and postnatal care has led to an increase in the survival rate of patients with CDH. However, some survivors experience mid- and long-term disabilities and complications requiring treatment and follow-up. In recent years, the establishment of clinical practice guidelines has been promoted in various medical fields to offer optimal medical care, with the goal of improvement of the disease' outcomes, thereby reducing medical costs, etc. Thus, to provide adequate medical care through standardization of treatment and elimination of disparities in clinical management, and to improve the survival rate and mid- and long-term prognosis of patients with CDH, we present here the clinical practice guidelines for postnatal management of CDH. These are based on the principles of evidence-based medicine using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The recommendations are based on evidence and were determined after considering the balance among benefits and harm, patient and society preferences, and medical resources available for postnatal CDH treatment.

Optimal timing of surgery in infants with prenatally diagnosed isolated left-sided congenital diaphragmatic hernia: a multicenter, cohort study in Japan

PURPOSE

To date, there is no compelling evidence of the optimal timing of surgery for congenital diaphragmatic hernia (CDH). This study aimed to establish the optimal timing of surgery in neonates with isolated left-sided CDH.

METHODS

This multicenter cohort study enrolled 276 patients with isolated left-sided CDH at 15 institutions. Based on the timing of surgery, the patients were classified into four groups [< 24 h (G1), 24-47 h (G2), 48-71 h (G3), and ≥ 72 h (G4)]. The clinical outcomes were compared among the groups using a logistic regression model, after adjusting for potential confounders, such as disease severity.

RESULTS

Multivariate analyses showed that G2 also had a lower mortality rate than the other groups. In mild and severe cases, there were no significant differences in mortality across the four groups. In moderate cases, G2 resulted in significantly increased survival rates, compared with G1.

CONCLUSION

The study results suggest that surgery within 24 h of birth is not recommended for patients with moderate severity CDH, that there is no benefit in the delay of surgery for more than 72 h in mild severity CDH patients, and that there is no definite optimal time to perform surgery in severe cases of CDH.

Extracorporeal Membrane Oxygenation in Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is characterized by failure of diaphragmatic development with lung hypoplasia and persistent pulmonary hypertension of the newborn (PPHN). If conventional treatment with gentle ventilation and optimized vasoactive medication fails, extracorporeal membrane oxygenation (ECMO) may be considered. The benefits of ECMO in CDH are still controversial, since there are only few randomized trials demonstrating the advantages of this therapeutic option. At present, there is no precise prenatal and/or early postnatal prognostication parameter to predict reversibility of PPHN in CDH patients. Indications for initiating ECMO include either respiratory or circulatory parameters, which are also undergoing continuous refinement. Centers with higher case numbers and the availability of ECMO published promising survival rates, but data on long-term results, including morbidity and quality of life, are rare. Survival might be influenced by the timing of ECMO initiation and the timing of surgical repair. In this regard a trend toward early initiation of ECMO and early surgery on ECMO exists. The results concerning the cannulation modes are similar and a consensus on time limit for ECMO runs does not exist. The use of ECMO in CDH will continue to be evaluated, and prospective randomized trials and registry network are necessary to help answering the addressed questions of patient selection and management.

Congenital diaphragmatic hernia repair in patients on extracorporeal membrane oxygenation: How early can we repair?

BACKGROUND

The benefits to early repair (<72 h postcannulation) of infants with congenital diaphragmatic hernia (CDH) on extracorporeal membrane oxygenation (ECMO) are increasingly recognized. Yet it is not known if even earlier repair (<24 h) results in comparable or improved patient outcomes. The goal of this study was to compare "super-early" (<24 h) to early repair (24-72 h) of CDH patients on ECMO.

METHODS

A retrospective review of infants with CDH placed on ECMO (2004-2017; n = 72) was performed. Data collected on the patients repaired while on ECMO within 72 h of cannulation (n = 33) included pre- and postnatal disease severity stratification variables and postnatal outcomes. Comparison groups were those patients repaired within 24 h of cannulation (n = 14) and those repaired between 24 and 72 h postcannulation (n = 19).

RESULTS

Patients undergoing "super-early" (<24 h) repair had an average survival of 71.4% compared to the average survival of 59.7% in the early repair group. Pre- and postnatal variables predicting disease severity were not significantly different between the groups. Mean hospital stays, ventilator days, and cannulation days were statistically similar between the groups.

CONCLUSIONS

Repair of patients with CDH patients on ECMO at less than 24 h postcannulation achieves outcomes that are comparable to those of repair between 24 and 72 h. While the present data suggest that there is not a "too early" time point for CDH repair on ECMO, larger multicenter studies are needed to validate our findings and determine the overall benefits.

TYPE OF STUDY

Retrospective comparative study.

LEVEL OF EVIDENCE

Level III.

Evaluating the utility of the "late ECMO repair": a congenital diaphragmatic hernia study group investigation

PURPOSE

Optimal timing of congenital diaphragmatic hernia (CDH) repair in patients requiring extracorporeal membrane oxygenation (ECMO) remains controversial. The "late ECMO repair" is an approach where the patient, once deemed stable for decannulation, is repaired while still on ECMO to enable expeditious return to ECMO if surgery induces instability. The goal of this study was to investigate the potential benefit of this approach by evaluating the rate of return to ECMO after repair.

METHODS

The CDH Study Group database was used to analyze CDH patients requiring ECMO support. The primary outcome was return to ECMO within 72 h of CDH repair among those repaired following ECMO decannulation ("post-ECMO" patients). Secondary outcomes were death within 72 h of repair and cumulative death and return to ECMO rate.

RESULTS

A total of 668 patients were repaired post-ECMO decannulation. Six patients (0.9%) in the post-ECMO group required return to ECMO within 72 h of surgery and a total of 19 (2.8%) died or returned to ECMO within 72 h of surgery.

CONCLUSION

The rate of return to ECMO and death following CDH repair is extremely low and does not justify the risks inherent to "on-ECMO" repair. Patients stable to come off ECMO should undergo repair after decannulation.

Extracorporeal membrane oxygenation in infants with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly which impairs normal pulmonary development leading to acute and chronic respiratory failure, pulmonary hypoplasia, pulmonary hypertension, and mortality. CDH is the most common non-cardiac indication for neonatal ECMO. Prenatal and postnatal predictors of CDH severity aid in patient selection. Centers vary in preferred mode of ECMO and timing of CDH repair. Survivors of severe CDH with ECMO are at risk for long-term sequelae including neurodevelopmental delays.

Early versus late surgical correction in congenital diaphragmatic hernia

INTRODUCTION

The timing of surgical repair in patients with congenital diaphragmatic hernia has been a controversial topic over the years, and there is still no agreement as to whether immediate repair or late surgery with preoperative stabilization is preferable.

METHODS

To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.

RESULTS AND CONCLUSIONS

We identified four systematic reviews including 38 studies overall, of which two were randomized trials. We concluded it is not clear whether immediate surgical repair in congenital diaphragmatic hernia increases mortality or decreases hospitalization days compared to late repair because the certainty of evidence is very low.

Appropriate timing of surgery for neonates with congenital diaphragmatic hernia: early or delayed repair?

PURPOSE

This study was aimed to evaluate the influence of timing of surgery on patient outcomes, and to clarify appropriate timing of surgery in neonates with congenital diaphragmatic hernia (CDH).

METHODS

A total of 477 neonates with isolated CDH were included. Patients were classified into two groups by timing of surgery: early repair (ER) (≤48 h) and delayed repair (DR) (>48 h). The primary outcome was 90-day survival, with treatment duration (ventilation, oxygen, and hospitalization) being a secondary outcome. To adjust for disease severity, patients were stratified into three severities by Apgar score 1 min ("mild" 8-10, "moderate" 4-7, and "severe" 0-3), and outcomes were compared between ER and DR within each severity.

RESULTS

Although 90-day survival was significantly different among the three severities ("mild" 97%, "moderate" 89%, and "severe" 76%, p = 0.002), there were no differences in 90-day survival between DR and ER within each severity. In "mild", there were no differences in treatment duration between ER and DR. In "moderate", treatment duration was shorter in ER than DR (ventilation 11 vs. 16 days, oxygen 15 vs. 20 days, and hospitalization 34 vs. 48 days). In "severe", treatment duration was shorter in ER than DR, while the best OI was higher in DR than ER.

CONCLUSIONS

Timing of CDH repair seems to have no influence on 90-day survival regardless of disease severity. Patients with moderate severity may benefit from the early repair by reducing treatment duration.

Management of congenital diaphragmatic hernia: A systematic review from the APSA outcomes and evidence based practice committee

OBJECTIVE

Variable management practices complicate the identification of optimal strategies for infants with congenital diaphragmatic hernia (CDH). This review critically appraises the available evidence to provide recommendations.

METHODS

Six questions regarding CDH management were generated. English language articles published between 1980 and 2014 were compiled after searching Medline, Cochrane, Embase and Web of Science. Given the paucity of literature on the subject, all studies irrespective of their rank in the levels of evidence hierarchy were included.

RESULTS

Gentle ventilation with permissive hypercapnia provides the best outcomes. Initial high frequency ventilation may be considered but its overall efficacy is unproven. Routine inhaled nitric oxide (iNO) or other medical adjuncts for acute, severe pulmonary hypertension demonstrate no benefit. Evidence does not support routine administration of pre- or postnatal glucocorticoids. Mode of extracorporeal membrane oxygenation (ECMO) has little bearing on outcomes. While the overall timing of repair does not impact outcomes, early repair on ECMO has benefits. Open repair leads to significantly fewer recurrences. Polytetrafluoroethylene (PTFE) is the most durable patch repair material.

CONCLUSIONS

Limited high-level evidence prevents the development of robust management guidelines for CDH. Prospective, multi-institutional studies are needed to identify best practices and optimize outcomes.

Factors associated with survival in infants with congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation: a report from the Congenital Diaphragmatic Hernia Study Group

OBJECTIVE

To identify factors associated with survival in patients with congenital diaphragmatic hernia (CDH) treated with extracorporeal membrane oxygenation (ECMO).

METHODS

We retrospectively analyzed the data on 3100 patients with CDH in the Congenital Diaphragmatic Hernia Study Group from 82 participating pediatric surgical centers (1995-2004). Covariates considered included prenatal and perinatal clinical information, specifics of surgical repair, and the duration of extracorporeal support.

RESULT

Nine hundred seven patients from the registry were identified as having been both managed with ECMO and undergone attempted surgical repair. The survival rate for the entire Congenital Diaphragmatic Hernia Study Group registry was 67% and 61% for those receiving ECMO in whom repair was attempted (P < .001). Among ECMO-treated children, survivors had a greater estimated gestational age (38 +/- 2 vs 37 +/- 2 weeks; P < .01), greater birth weights (3.2 +/- 0.5 vs 2.9 +/- 0.5 kg; P < .001), were less often prenatally diagnosed (53% vs 63%; P < .01), and were on ECMO for a shorter period of time (9 +/- 5 vs 12 +/- 5 days; P < .001). In logistic regression models, therapy-related variables, including the duration of ECMO, the nature of diaphragmatic repair, and the type of abdominal closure and certain comorbidities, particularly the presence of a concomitant severe cardiac abnormality, were independently associated with outcome.

CONCLUSION

Our model identifies a group of pre-surgical and postsurgical parameters that predict survival rate in patients with CDH on ECMO support. This model was derived from the retrospective data from a large database and will need to be prospectively tested.

The long-term follow-up of patients with a congenital diaphragmatic hernia: a broad spectrum of morbidity

Congenital diaphragmatic hernia (CDH) is a life-threatening anomaly with a mortality rate of approximately 40-50%, depending on case selection. It has been suggested that new therapeutic modalities such as nitric oxide (NO), high frequency oxygenation (HFO) and extracorporal membrane oxygenation (ECMO) might decrease mortality associated with pulmonary hypertension and the sequelae of artificial ventilation. When these new therapies indeed prove to be beneficial, a larger number of children with severe forms of CDH might survive, resulting in an increase of CDH-associated complications and/or consequences. In follow-up studies of infants born with CDH, many complications including pulmonary damage, cardiovascular disease, gastro-intestinal disease, failure to thrive, neurocognitive defects and musculoskeletal abnormalities have been described. Long-term pulmonary morbidity in CDH consists of obstructive and restrictive lung function impairments due to altered lung structure and prolonged ventilatory support. CDH has also been associated with persistent pulmonary vascular abnormalities, resulting in pulmonary hypertension in the neonatal period. Long-term consequences of pulmonary hypertension are unknown. Gastro-esophageal reflux disease (GERD) is also an important contributor to overall morbidity, although the underlying mechanism has not been fully understood yet. In adult CDH survivors incidence of esophagitis is high and even Barrett's esophagus may ensue. Yet, in many CDH patients a clinical history compatible with GERD seems to be lacking, which may result in missing patients with pathologic reflux disease. Prolonged unrecognized GERD may eventually result in failure to thrive. This has been found in many young CDH patients, which may also be caused by insufficient intake due to oral aversion and increased caloric requirements due to pulmonary morbidity. Neurological outcome is determined by an increased risk of perinatal and neonatal hypoxemia in the first days of life of CDH patients. In patients treated with ECMO, the incidence of neurological deficits is even higher, probably reflecting more severe hypoxemia and the risk of ECMO associated complications. Many studies have addressed the substantial impact of the health problems described above, on the overall well-being of CDH patients, but most of them concentrate on the first years after repair and only a few studies focus on the health-related quality of life in CDH patients. Considering the scattered data indicating substantial morbidity in long-term survivors of CDH, follow-up studies that systematically assess long-term sequelae are mandatory. Based on such studies a more focused approach for routine follow-up programs may be established.

Congenital diaphragmatic hernia: improved surgical results should influence abortion decision making

AIMS

To compare surgical results for congenital diaphragmatic hernia (CDH) in two Scandinavian university hospitals and to evaluate the effects of abortions on the clinical profile of CDH in Iceland.

METHODS

A retrospective study including all CDH-cases in Iceland 1983-2002 and children referred to Lund University Hospital 1993-2002. Aborted fetuses with CDH from a nation-wide Icelandic abort-registry were also included.

RESULTS

In Iceland, 19 out of 23 children with CDH were diagnosed < 24 hours from delivery, one with associated anomalies. Eight fetuses were diagnosed prenatally and seven of them aborted, three having isolated CDH at autopsy. In Iceland, 15 of 18 children operated on survived surgery (83% operative survival). In Lund 28 children were treated with surgery, 23 of them diagnosed early after birth or prenatally. Four children did not survive surgery (86% operative survival) and 9 (31%) had associated anomalies. All the discharged children treated in Iceland and Lund are alive, 3-22 years postoperatively.

CONCLUSION

CDH is a serious anomaly where morbidity and mortality is directly related to other associated anomalies and pulmonary hypoplasia. However, majority of CDH patients do not have other associated anomalies. In spite of improved surgical results (operative mortality < 20%), a large proportion of pregnancies complicated with CDH are terminated. We conclude that the improved survival rate after corrective surgery must be emphasized when giving information to parents regarding abortion of fetuses with a prenatally diagnosed CDH.

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.

New approaches to managing congenital diaphragmatic hernia

A number of new techniques have been studied for managing newborns with congenital diaphragmatic hernia and respiratory insufficiency. Among these have been the techniques of delayed approach to the repair of the diaphragmatic hernia; permissive hypercapnia; nitric oxide and surfactant administration; intratracheal pulmonary ventilation; liquid ventilation; perfluorocarbon-induced lung growth; and lung transplantation. These interventions are at various stages of development and evaluation of effectiveness. All, however, are being explored in the hopes of improving outcome in patients with congenital diaphragmatic hernia who continue to have significant morbidity and mortality in the newborn period.

Congenital Diaphragmatic Hernia Repair on Extracorporeal Life Support: A Decade of Lessons Learned

Congenital diaphragmatic hernia (CDH) is a vexing anomaly that manifests with variable pulmonary compromise in neonates. More than one-third of neonates with CDH require extracorporeal membrane oxygenation (ECMO) for refractory pulmonary hypertension (PHN). To assess the outcome of neonates having CDH repair on ECMO, we reviewed our experience for babies treated between 1992 and 2003. Of 97 neonates with CDH, 40 required ECMO, and 30 were repaired on bypass. Eighteen were supported by veno-venous bypass (VV) and 12 by veno-arterial bypass (VA). While on ECMO, transfusion requirements increased twofold postoperatively (15 to 33 cc · kg-1 · day-1, P = 0.03) and then significantly decreased after decannulation (1.5 cc · kg-1 · day-1, P < 0.01). Non-intracranial hemorrhage occurred in 7 (23%) infants and intracranial hemorrhage in 3 (10%). Twelve (40%) infants died; one (3%) on ECMO secondary to refractory PHN. The mean length of stay for the 18 (60%) survivors was 48 days. Comparisons between survivors and nonsurvivors showed a significantly increased mortality for infants placed on VA bypass ( P < 0.01). However, no other variable was predictive of survival. We conclude that CDH repair on ECMO is technically feasible, shows similar survival to the Extracorporeal Life Support Organization (ELSO) registry, and is associated with few bleeding complications.

Nihilism in the 1990s: the true mortality of congenital diaphragmatic hernia

OBJECTIVE

Reported survival in congenital diaphragmatic hernia (CDH) fails to allow for case selection bias. This study reports the incidence of CDH in a geographically defined population over 11 years and assesses the effect of new therapies (high-frequency oscillatory ventilation, extracorporeal membrane oxygenation, inhaled nitric oxide, and delayed surgery) on survival when case selection is avoided.

METHODS

A retrospective review of cases from a regional case registry, the Northern Region Congenital Anomaly Survey, was conducted.

RESULTS

A total of 185 cases were identified. Mortality was 62% and did not vary significantly during the study period. Mortality was unaffected by the introduction of new therapies. There was a significant inverse correlation between the rate of elective termination and survival of live borns. The presence of an additional anomaly increased mortality to 79%.

CONCLUSIONS

The mortality of CDH when complete case ascertainment is achieved is unaffected by new therapies. The survival rate is principally determined by the rate of antenatal termination and the incidence of associated anomalies. Reports of improved survival of CDH should be interpreted with caution, as variations in outcome are more likely to be explained by case selection artifact.

Venovenous versus venoarterial extracorporeal membrane oxygenation in congenital diaphragmatic hernia

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has a significant role as a final rescue modality in severe respiratory failure of the newborn with congenital diaphragmatic hernia (CDH). The objective of this study was to compare the efficiency of venovenous (VV) versus venoarterial (VA) ECMO in newborns with CDH.

METHODS

A retrospective report of 11 years experience (1990 through 2001) of a single center, comparing VV and VA ECMO is given. VV ECMO was the preferred rescue modality for respiratory failure unresponsive to maximal medical therapy. Only when the placement of a VV ECMO 14F catheter was not possible, VA ECMO was used. Forty-six patients met ECMO criteria; 26 were treated with VV ECMO and 19 with VA ECMO. One patient underwent conversion from VV to VA ECMO.

RESULTS

Before ECMO, there was no difference between VV and VA ECMO patients in mean oxygenation index (83 v 83), mean airway pressure (18.4 v 18.9 cm H(2)O), ECMO cannulation age (28 v 20 hours), or in the percentage of patients who needed dopamine and dobutamine (100% v 100%). From November 1994, nitric oxide (NO) was available; before ECMO, 11 of 14 (79%) VV ECMO patients received NO versus 9 of 10 (90%) patients in the VA group. VV ECMO patients were larger (3.34 v 2.77 kg; P <.05) and of advanced gestational age (39.0 v 36.9 wk; P <.05) compared with VA ECMO patients. There was no significant difference between VV and VA ECMO patients in survival rate (18 of 26, 69% v 13 of 19, 68%), ECMO duration (152 v 150 hours), time of extubation (32.0 v 33.5 days), age at discharge (73 v 81 days), or incidence of short-term intracranial complications (3.8% v 10.5%) or myocardial stun (3.8% v 15.8%).

CONCLUSIONS

The authors conclude that VV ECMO is as reliable as VA ECMO in newborns with CDH in severe respiratory failure who need ECMO support and who can accommodate the VV double-lumen catheter. Because of its potential advantages, VV ECMO may be the preferred ECMO method in these infants.

Inhaled nitric oxide with early surgery improves the outcome of antenatally diagnosed congenital diaphragmatic hernia

BACKGROUND/PURPOSE

The outcome of antenatally diagnosed congenital diaphragmatic hernia (CDH) has remained poor despite aggressive therapeutic strategies. Since 1996, the authors have used a new approach including early surgery and inhaled nitric oxide (iNO). The aim of this study is to determine whether early surgery in combination with iNO improves the clinical outcome of antenatally diagnosed CDH.

METHODS

From 1988, 40 consecutive neonates with antenatally diagnosed CDH were admitted to the authors' hospital. Ten cases of fatal chromosomal anomalies or major cardiac anomalies were excluded from this study. From 1988 through 1995 (period 1: n = 13), delayed surgery was used in high-risk CDH. From 1996 through 2000 (period 2: n = 17), early surgery in combination with iNO was used. The severity of lung hypoplasia was evaluated using the fetal lung/thorax transverse area ratio (L/T). High-frequency oscillatory ventilation (HFOV) was used routinely during the study periods, and extracorporeal membrane oxygenation (ECMO) was used on basis of conventional entry criteria. The authors compared the clinical outcome, use of ECMO, and the L/T between the 2 periods retrospectively.

RESULTS

Patients in the 2 periods were comparable in terms of birth weight, gestational age, and the L/T. The mean age at surgery was 3.1 +/- 4.9 days in period 1, and 0.8 +/- 1.1 days in period 2. Fewer infants in period 2 compared with period 1 were treated with ECMO (period 1, 62% v period 2, 6%; P <.01). There was significant difference in the survival rate between the 2 periods (period 1, 38% v period 2, 94%; P <.01).

CONCLUSION

Our data suggest that early surgery and iNO improves the outcome and reduces the requirement of ECMO in the treatment of antenatally diagnosed CDH.

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.

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.

Neurodevelopmental outcome after congenital diaphragmatic hernia: Extracorporeal membrane oxygenation before and after surgery

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO) as a treatment of last resort for neonates with persistent pulmonary hypertension of the newborn (PPHN) caused by congenital diaphragmatic hernia (CDH) may be used for preoperative stabilization or postoperative rescue. The aim of this study was to examine the acute and long-term morbidity associated with pre- and postoperative ECMO.

METHODS

Neonates born with CDH and needing ECMO were classified into 2 groups. Group 1 consisted of neonates placed on ECMO after CDH surgery. Patients in group 2 underwent preoperative ECMO stabilization. Medical records after birth were evaluated. Growth, neuromotor and cognitive development, hearing, and behavior were evaluated. Student t test and chi(2) were used to determine statistical significance between groups.

RESULTS

Subjects in group 2 had significantly more days on ECMO and loop diuretics. Alkalosis was induced for a longer duration in group 2. At follow-up 3 to 9 years later, no differences were found between the 2 groups in growth parameters, neuromotor outcome, or behavior. However, in group 1, 2 of 9 children had significant hearing impairment necessitating amplification compared with 6 of 6 subjects in group 2.

CONCLUSIONS

Neonates with CDH first stabilized on ECMO (group 2) had a higher incidence of hearing loss compared with those needing ECMO postrepair (group 1). The etiology of this finding is not clear. This may be secondary to the prolonged period of hyperventilation or general intensive care that is part of the protocol for neonates who are electively stabilized on ECMO preoperatively. J Pediatr Surg 36:539-544.

Congenital diaphragmatic hernia: a meta-analysis of mortality factors

PURPOSE

The aim of this study was to review all available studies reported in the English-language literature from 1975 through 1998, and by meta-analysis assess the importance of prenatal diagnosis, associated malformations, side of hernia, timing of surgery, and study population on mortality rates in patients with congenital diaphragmatic hernia (CDH).

METHODS

One-hundred-two studies were identified, and 51 studies (2,980 patients) fulfilled the prespecified inclusion criteria. Studies were grouped according to study population into: (I) fetuses diagnosed prenatally; (II) neonates admitted to a treatment center; and (III) population-based studies.

RESULTS

Pooled total mortality rate was significantly higher in category I than in category III (75.6% v 58.2%, P < .001). Pooled hidden postnatal mortality rate (deaths before admittance to a treatment center) in population-based studies was 34.9%. Prenatally diagnosed patients in both category II and III had significantly higher mortality rates than those diagnosed postnatally. Mortality rates were significantly higher among CDH infants with associated major malformations compared with isolated CDH in all 3 categories. An increased mortality rate in right-sided CDH was found in category II and III.

CONCLUSIONS

Prenatal diagnosis of CDH, presence of associated major malformations, and the study population have a major influence on mortality rate. The very high mortality rate in studies of fetuses with a prenatal diagnosis of CDH should be taken into account in prenatal counselling.

Late versus early surgical correction for congenital diaphragmatic hernia in newborn infants

BACKGROUND

Congenital diaphragmatic hernia, although rare (1 per 2-4,000 births), is associated with high mortality and cost. Opinion regarding the timing of surgical repair has gradually shifted from emergent repair to a policy of stabilization using a variety of ventilatory strategies prior to operation. Whether delayed surgery is beneficial remains controversial.

OBJECTIVES

To summarize the available data regarding whether surgical repair in the first 24 hours after birth rather than later than 24 hours of age improves survival to hospital discharge in infants with congenital diaphragmatic hernia who are symptomatic at or immediately after birth.

SEARCH STRATEGY

Search of Medline (1966-1999), Embase (1978-1999) and the Cochrane databases using the terms "congenital diaphragmatic hernia" and "surg*"; citations search, and contact with experts in the field to locate other published and unpublished studies.

SELECTION CRITERIA

Studies were eligible for inclusion if they were randomized or quasi-randomized trials that addressed infants with CDH who were symptomatic at or shortly after birth, comparing early (<24 hours) vs late (>24 hours) surgical intervention, and evaluated mortality as the primary outcome.

DATA COLLECTION AND ANALYSIS

Data were collected regarding study methods and outcomes including mortality, need for ECMO and duration of ventilation, both from the study reports and from personal communication with investigators. Analysis was performed in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Two trials met the pre-specified inclusion criteria for this review. Both were small trials (total n<90) and neither showed any significant difference between groups in mortality. Meta-analysis was not performed because of significant clinical heterogeneity between the trials.

REVIEWER'S CONCLUSIONS

There is no clear support for either immediate (within 24 hours of birth) or delayed (until stabilized) repair of congenital diaphragmatic hernia, but a substantial advantage to either one cannot be ruled out. A large, multicenter randomized trial would be needed to answer this question.

Fetal stabilization for antenatally diagnosed diaphragmatic hernia

BACKGROUND/PURPOSE

Infants with congenital diaphragmatic hernia have pulmonary hypoplasia resulting in persistent pulmonary hypertension of neonates (PPHN), which is the main contributor to both high mortality and morbidity. The pulmonary artery bed in patients with congenital diaphragmatic hernia (CDH) is underdeveloped and is very sensitive to slight stimuli. It is, therefore, vital to avoid any factors that might increase pulmonary vascular resistance during the perinatal treatment of these patients. Recently, fetal anesthesia for perinatal stabilization in patients with CDH has been reported. However, the efficacy of this method remains controversial. The aim of this study is to analyze the benefits of fetal stabilization using fetal anesthesia in patients with CDH.

METHODS

The authors have seen 9 cases of antenatally diagnosed CDH and attempted fetal stabilization. The indication for fetal stabilization was a lung thoracic ratio of less than 0.2, without any severe associated anomalies. The protocol for fetal stabilization was (1) monitoring the fetal respiratory movement and heart beat by ultrasonography, (2) the administration of morphine (20 to 30 mg) and diazepam (5 mg) to the mother, (3) the confirmation of any interruptions in fetal movement followed by a cesarean section, (4) pancuronimum (0.5 mg) was given through the umbilical vessels, (5) intubation before clamping of the umbilical cord, and (6) high-frequency oscillatory ventilation (HFO) without bagging.

RESULTS

The lung-thratic ratio (LTR) was between 0.06 to 0.17 (average, 0.10+/-0.04). Operation was performed in 7 of 9 patients at between 2.5 and 27 hours after birth. The overall survival rate was 66.7% (6 of 9). All of the patients who underwent operation within 5 hours after birth survived.

CONCLUSIONS

Perinatal stabilization using fetal anesthesia was found to be effective in preventing PPHN and shortening the period of preoperative stabilization. It also improved the survival rate of patients with severe CDH.

Detrimental effects of standard medical therapy in congenital diaphragmatic hernia

OBJECTIVE

To evaluate the impact of a nonstandard ventilation strategy on survival in congenital diaphragmatic hernia (CDH).

BACKGROUND

Despite recent advances, including nitric oxide, CDH remains an unsolved problem with a mortality rate of 35% to 50%. Hyperventilation and alkalization remain common therapies.

METHODS

In 1992, the authors prospectively abandoned hyperventilation and alkalization. Patients are lightly sedated and ventilated with the lowest pressure providing adequate chest movement, and the rate is set to patient comfort. Nitric oxide and extracorporeal membrane oxygenation (ECMO) are reserved for life-threatening instability. Surgical repair is delayed 1 to 5 days. Sixty consecutive patients are compared with 29 previous patients treated with hyperventilation and alkalization, 13 before and 16 after the availability of ECMO.

RESULTS

Overall, 47 of 60 patients (78%) in study era 3 survived compared with 2 of 13 (15%) in the hyperventilation era and 7 of 16 (44%) in the hyperventilation/ECMO era (p < 0.0001). The disease severity and the incidence of associated anomalies did not differ between groups. To compare management strategies, patients who had treatment withheld because of lethal associated conditions were then removed from analysis. Peak inspiratory pressure and arterial pH were lower (p < 0.0001) and Paco2 was higher (p < 0.05) in era 3 than in the previous eras. The rate of pneumothorax (1.9%) decreased (p < 0.0001). In era 3, survival was 47 of 53 (89%) treated patients, and 23 of 25 inborn patients with isolated CDH survived (92%).

CONCLUSIONS

Nonstandard ventilatory support of patients with CDH has led to significantly improved survival rates. This study sets a survival benchmark and strongly suggests the negative effects of hyperventilation and alkalization.

Improved pulmonary function after surgical reduction of congenital diaphragmatic hernia in lambs

BACKGROUND/PURPOSE

Modern trends are toward delayed surgical reduction of congenital diaphragmatic hernia. This study was conducted to verify the hypothesis that the "ease" of ventilation found in the authors' postoperative experience in infants with congenital diaphragmatic hernia (CDH) is associated with postsurgical improvement in pulmonary mechanics.

METHODS

Very severe CDH was surgically induced in utero at 90 days' gestation in 31 lambs. At birth pulmonary mechanics (PeDS-Lab) was measured in these preterm lambs with (n = 24) and without (n = 7) early surgical reduction, and in eight non-CDH controls over the same period; functional residual capacity (FRC) also was obtained from 14 of the 31 CDH lambs (seven reduced animals and seven unreduced ones). Management excluded aspiration from the thorax and insertion of chest drains.

RESULTS

After 30 minutes of life CDH animals with early surgical reduction demonstrated significantly greater improvement in lung volume, pulmonary mechanics, and oxygenation than those without reduction: FRC, 235% versus 19%; compliance, 57% versus 14%; minute ventilation, 71% versus 30%; and PO2, 143% versus -15%. Over the same period, in preterm controls without CDH, only the compliance varied significantly, demonstrating a 32% increase.

CONCLUSION

Based on the mechanics of breathing in these lambs, the authors speculate that neonates with CDH could benefit from early surgical repair because of improvement in pulmonary function, provided extra care is taken to prevent pulmonary overdistension.

[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.

Delayed repair of congenital diaphragmatic hernia with early high-frequency oscillatory ventilation during preoperative stabilization

PURPOSE

The authors reviewed their experience in the management of CDH after the introduction of early high-frequency oscillatory ventilation (HFOV) during the preoperative stabilization period and delayed CDH repair.

METHODS

This is a retrospective analysis of 24 consecutive infants with CDH treated at University of California, Irvine Medical Center (UCIMC) during a 36-month period from January 1993 to December 1996.

RESULTS

Two patients were excluded from the study: one fetus with a prenatal diagnosis was referred for fetal surgery; one infant received CDH repair at another institution 2 weeks before transfer to UCIMC. Eight (36%) infants were inborn, and nine (41%) had a prenatal diagnosis of CDH. Median gestational age was 40 weeks (range, 29 to 42 weeks). Median birth weight was 3,019 g (range, 1,205 to 4,337 g). The defect was left sided in 18 infants (86%). Twenty-one infants were intubated within 5 hours of life, 15 had an AaDO2 greater than 610, 11 had an oxygenation index greater than 40, and 11 had a pH of less than 7.2. The median ratio of pulmonary artery pressure to systemic blood pressure was 0.93 (range, 0.51 to 1.15) in 12 infants. Eighteen infants were placed on HFOV within a median of 1 hour of life. Nitric oxide was given to six infants and surfactant to eight. Four infants were referred for extracorporeal membrane oxygenation (ECMO). Repair of CDH was performed on infants at a median age of 33.5 hours (range, 5.5 to 322). Six (30%) received a prosthetic patch. Overall 18 of 22 infants survived (81%); three survivors received ECMO. Two infants of the survivor group had congenital heart anomalies: one ventricular septal defect (VSD) and one double-outlet right ventricle with a VSD. Of the four nonsurvivors, one had lethal cardiac anomalies and bilateral CDH, two had severe bilateral pulmonary hypoplasia (one received ECMO), and one infant was a 29-week premature baby who did not qualify for ECMO.

CONCLUSION

We report a survival rate of 81% (18 of 22) with the management of CDH by delayed surgical repair, early postnatal HFOV, and selective referral for ECMO.

Continuous intrapulmonary distension with perfluorocarbon accelerates neonatal (but not adult) lung growth

BACKGROUND/PURPOSE

We have previously demonstrated that experimental fetal tracheal ligation reverses the structural and physiological effects of pulmonary hypoplasia associated with congenital diaphragmatic hernia. The purpose of this study was to determine if lung growth could be similarly accelerated postnatally by continuous liquid-based intrapulmonary distension.

METHODS

Ten neonatal lambs were divided into two experimental groups. Five neonatal animals underwent a right thoracotomy with isolation of the anterior superior segment of the right upper lobe. A pressure monitoring catheter was introduced and perfluorocarbon (PFC) was instilled into the segment. Animals were subjected to a 21-day distention period with continuous maintenance of 7 to 10 mm Hg intrabronchial pressure. Five other neonatal animals used as age- and weight-matched controls were killed immediately after distension with PFC to 7 to 10 mm Hg. To evaluate the effect of age on postnatal growth, identical procedures were performed on seven mature sheep. Four adult animals underwent a 21-day distension with PFC, and three animals were killed immediately after PFC distension.

RESULTS

Neonatal animals who underwent distension showed a significant acceleration of lung growth based on right upper lobe volume to body weight ratio (P = .0019), total alveolar number (P = .003), and total alveolar surface area (P = .006), when compared with controls. Alveolar growth was attributed to an increased alveolar number rather than increased alveolar size based on a normal histological appearance, normal airspace fraction (P = NS), and normal alveolar numerical density (P = NS). In contrast, no significant differences in lung growth or maturation indices were present in adult animals.

CONCLUSIONS

From this preliminary data we conclude: (1) Liquid-based airway distension does accelerate postnatal lung growth, (2) lung architecture remains normal during this period of accelerated growth, (3) adult sheep do not respond to liquid-based airway distension with lung growth, and (4) prolonged exposure to intrapulmonary PFC appears to be safe. We speculate that stretch is the stimulus for lung growth because there are no known growth factors present in PFC.

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.

Improved results in patients who have congenital diaphragmatic hernia using preoperative stabilization, extracorporeal membrane oxygenation, and delayed surgery

Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia. The pulmonary vascular bed may be extremely reactive to various stimuli, and in the treatment it is important to avoid pulmonary vasospasm. The strategy in our institution since 1990 has involved a prolonged preoperative stabilization with gentle mechanical ventilation. Pressures have been kept as low as possible, and slight hypercarbia has been accepted. Peak inspiratory pressures exceeding 35 cm H2O have been avoided. Extracorporeal membrane oxygenation (ECMO) has been used according to standard inclusion criteria. Nitric oxide and high-frequency oscillation have been added to the therapeutic modalities during the study period. When the patient was considered stabilized, surgical repair was undertaken after a delay of 24 to 96 hours. In patients on ECMO who could not be decannulated, surgical repair was undertaken while on ECMO. From 1990 through 1995, 52 patients were admitted with a diagnosis of CDH. Forty-three of these were risk group patients presenting with respiratory distress within 6 hours after birth. A total of 48 patients survived (survival rate 92%), and 39 of the risk group patients (survival rate 91%). There were only four hospital deaths, all with contraindications to ECMO. It is suggested that the adopted protocol is beneficial in the treatment of CDH and that the fraction of patients who have pulmonary hypoplasia incompatible with life is smaller than previously believed.

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.

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.

Prenatal diagnosis of congenital diaphragmatic hernia and pulmonary hypoplasia and therapeutic strategy

The outcome of fetuses with congenital diaphragmatic hernia (CDH) has been reported to be fatal when pulmonary hypoplasia (PH) is severe. As an indicator of PH, we attempted to measure the lung-thorax transverse area ratio (L/T) using ultrasonic echography. Immediate postnatal surgery was performed using high-frequency oscillatory ventilation (HFOV) and sometimes followed by extracorporeal membrane oxygenation (ECMO). Eighteen fetuses were treated and 14 survived. L/T correlated well with the best preductal arterial blood gas data before surgical reduction during manual ventilation and HFOV, while preductal PO2 and alveolar-arterial oxygen differences from patients managed with HFOV were better than those in patients with manual ventilation. Although L/T also correlated with the duration of O2 therapy and hospitalization in survivors without major anomalies, there was no significant difference between L/T in survivors and nonsurvivors. Because delayed institution of ECMO and complications related to ECMO management seemed to be a major cause of death in non-survivors, the unsalvageable L/T due to PH was estimated to be below 0.06 for HFOV and below 0.1 for conventional ventilation based on the correlation between L/T and preductal P02. These results suggest that L/T is a useful indicator of PH in patients with CDH and also that HFOV is advantageous in treating CDH with PH. The advantage of prenatal diagnosis in predicting unsalvageable L/Ts, should be considered in the therapeutic strategy.

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.

Effect of very delayed repair of congenital diaphragmatic hernia on survival and extracorporeal life support use

BACKGROUND

Since November 1992, operative repair in neonates with congenital diaphragmatic hernia (CDH) at this institution was delayed until respiratory insufficiency had resolved.

METHODS

A retrospective analysis was performed (n = 33) comparing delayed repair with our previously reported institutional experience with immediate repair from January 1988 to October 1992 (n = 66). Infants with severe genetic defects or moribund conditions or who were premature were not considered candidates for repair or extracorporeal life support (ECLS), but they were included in the survival analysis. Survival was defined as hospital discharge. Data were compared with an independent t test or Pearson chi-squared test.

RESULTS

Mean age at repair was 8.9 +/- 4.5 days (range, 3 to 20 days). Eleven infants in the study group were placed on ECLS (33% versus 68% in the comparison group; p = 0.001). Six of these infants survived (55% versus 58% in the comparison group; p = 0.846). Of these survivors, one patient was repaired while on ECLS, and the remainder underwent repair after decannulation from ECLS. All 20 of the remaining candidates for repair survived without need for ECLS. Overall survival was 79% versus 56% in the comparison group (p = 0.027).

CONCLUSIONS

Our current data suggest that very delayed repair of newborns with CDHs is associated with an increase in the overall survival and a decrease in the use of ECLS when compared with previous experience at this institution.

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.

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.

Inhalation of nitric oxide as a treatment of pulmonary hypertension in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) still has a mortality risk of around 40%. The concomitant pulmonary hypoplasia and the persistent pulmonary hypertension are of major prognostic importance. The use of a selective pulmonary vasodilator may revert this vicious circle that is fatal to many children. Inhalation of nitric oxide (NO) has been suggested as a rational treatment of this condition. The authors report three cases of high-risk infants with CDH where NO was used successfully. It is concluded that hypoxemia in CDH can be treated successfully with NO inhalation when conventional treatment fails, and it may in some cases prove to be an alternative to ECMO.

Preoperative cardiorespiratory trends in infants with congenital diaphragmatic hernia

The objective of this study was to determine the cardiovascular and pulmonary adaptations of infants with congenital diaphragmatic hernia (CDH) from birth until delayed surgery through the use of continuous monitoring. Continuous cardiovascular (HR, heart rate variability [HR-SD], BP, blood pressure variability [BP-SD], and oxygen saturation) and ventilatory (minute volume, airway pressure, and effective compliance) measurements were made on-line, using a computerized whole-body plethysmograph-incubator (Vital-trends, VT1000), in nine ventilated infants with CDH. Data collection commenced at birth and continued until surgery. Minute mean values for each variable were recorded. Hourly means were computed from the minute means, averaged across infants each hour over the first 50 hours of life, and regressed against postnatal age. Results showed a significant increase in BP (P < .01), BP-SD (P < .05), HR-SD (P < .04), and pH (P < .02) versus postnatal age, and a decrease in PaCO2 (P < .04), FIO2 (P < .001), Alveolar-arterial oxygen gradient (P < .003), and oxygenation index (P < .002). Infants with CDH show cardiopulmonary trends over the first 2 days of life that are qualitatively similar to those of normal newborn infants. Deviation from these idealized patterns may identify an infant who is not responding satisfactorily to the given therapy and who may require alternative treatment modalities.

Congenital diaphragmatic hernia: survival treated with very delayed surgery, spontaneous respiration, and no chest tube

This report suggests that stabilization of the intrauterine to extrauterine transitional circulation combined with a respiratory care strategy that avoids pulmonary overdistension, takes advantage of inherent biological cardiorespiratory mechanics, and very delayed surgery for congenital diaphragmatic hernia results in improved survival and decreases the need for extracorporeal membrane oxygenation (ECMO). This retrospective review of a 10-year experience in which the respiratory care strategy, ECMO availability, and technique of surgical repair remained essentially constant describes the evolution of this method of management of congenital diaphragmatic hernia.

Fetal surgery

Fetal surgery, as defined for the purpose of this chapter, is the act of opening the gravid uterus, surgically correcting a fetal abnormality, and returning the fetus to the uterus for postoperative recovery and continued gestational development. By this definition, human fetal surgery has now been performed for more than a decade, primarily at a single center (1). Tremendous progress has been made in our understanding of the natural history and pathophysiology of fetal disease, in solving the technical challenges of fetal surgery, and in intra- and postoperative care and monitoring of the maternal-fetal unit. However, success and general application of fetal surgery continue to be limited by a number of unsolved and formidable problems. The most important of these is the control of preterm labor, which is the Achilles heel of fetal surgery. Preterm labor is to the infantile field of fetal surgery what rejection was to the field of transplantation. The discovery of effective tocolysis would be analogous to the development of effective immunosuppression and would allow fetal surgery to achieve its full potential. In addition, less invasive methods of operating on the fetus are emerging that will further reduce the maternal and fetal risk of this currently highly invasive treatment.