A correlation of pulmonary hypoplasia, mean airway pressure, and survival in congenital diaphragmatic hernia treated with extracorporeal membrane oxygenation

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.

Improvement of pulmonary hypoplasia associated with congenital diaphragmatic hernia by in utero CFTR gene therapy

Congenital diaphragmatic hernia (CDH) may be an ideal candidate disease for in utero gene therapy as disrupted fetal lung growth plays a significant role in disease outcome. We previously demonstrated that transient in utero overexpression of CFTR during fetal development resulted in lung epithelial proliferation and differentiation. We hypothesized that gene therapy with CFTR would improve the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH). CDH was induced by the herbicide 2,4-dichlorophenyl-4-nitrophyl ether (nitrofen) following maternal ingestion at either 10 or 13 days gestation. In utero gene transfer of the CFTR gene was subsequently performed at 16 days gestation. Examination of the fetuses at 22 days gestation revealed little improvement in the CFTR-treated lungs following induction of hernias with nitrofen at 10 days gestation. However, the CFTR gene treatment significantly improved internal surface area, saccular density, overall saccular number, and amount of saccular air space in the lungs that were treated with nitrofen at 13 days gestation. RT-PCR demonstrated that gene transfer occurred following treatment at 13 days gestation but not in the lungs treated with nitrofen at 10 days gestation, despite gene transfer at the same gestational age (16 days) in both groups. As disruption of lung development correlates with the gestational stage at which nitrofen exposure occurs, these results confirmed previous findings that in utero gene transfer efficiency depends on the stage of lung development. Lung development may be significantly delayed in human CDH to allow for successful gene transfer later in gestation, providing a substantial therapeutic window.

Extracorporeal life support: history and new directions

This review recounts the development of extracorporeal life support (ECLS, ECMO) from the laboratory and early clinical trials to routine clinical application. Lessons from neonatal ECMO have led to better understanding of neonatal lung physiology, improved methods of treatment, and application of ECLS to other patient populations.

Infant pulmonary function in a randomized trial of fetal tracheal occlusion for severe congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) carries a high mortality risk secondary to pulmonary hypoplasia and respiratory failure. In experimental animals, fetal tracheal occlusion (TO) induces lung growth and morphologic maturation. We measured indicators of pulmonary function in 20 infants who were enrolled in a randomized trial of fetal TO as treatment for severe CDH [nine with conventional treatment (controls); 11 with TO]. We hypothesized that TO would improve lung function. At birth, the TO group had a lower mean gestational age (30.8 +/- 2.0 versus 37.4 +/- 1.0 wk; p=0.0002). All infants required assisted ventilation. Mortality did not differ between groups (64 versus 78%, TO and control, respectively; p=0.64). We measured respiratory mechanics at four study points: 1) first 24 h, 2) before CDH operative repair (5.9 +/- 2.2 d), 3) immediately after repair (7.0 +/- 2.2 d), and 4) before elective extubation (32.5 +/- 16.1 d). We calculated perioperative oxygenation index and alveolar-arterial oxygen difference to assess efficiency of pulmonary gas exchange. Data were analyzed by univariate and repeated measures techniques. Respiratory system compliance (Crs) was low. The rate of increase in Crs over the four study points was greater in the TO group than in control subjects. Crs in the TO group was significantly greater at study 2 (0.28 +/- 0.12 versus 0.17 +/- 0.04 mL.cm H2O(-1).kg(-1); p=0.02) and study 4 (0.93 +/- 0.45 versus 0.51 +/- 0.16 mL.cmH2O(-1).kg(-1); p=0.02). oxygenation index did not differ between groups, but alveolar-arterial oxygen difference was lower in the TO infants. We conclude that fetal TO for severe CDH results in modest improvements in neonatal pulmonary function that are of questionable clinical significance.

Right congenital diaphragmatic hernia: Prenatal assessment and outcome

PURPOSE

To understand the natural history of right congenital diaphragmatic hernia (CDH), the authors retrospectively reviewed 27 cases of right CDH that presented for prenatal evaluation or postnatal treatment.

METHODS

Between 1995 and September 2002, a total of 194 cases of fetal CDH were evaluated and included 22 right-sided defects. The authors reviewed prenatal diagnostic studies (ultrasound scan, magnetic resonance imaging [MRI] echocardiography) and pre- and postnatal outcomes in these 22 cases of right CDH. Five additional cases of right CDH without a prenatal diagnosis were reviewed.

RESULTS

The mean gestational age at evaluation was 26.1 weeks. The lung area to head circumference ratio (LHR) ranged from 0.32 to 2.5. In all cases, the fetal liver was herniated into the right chest. Associated anomalies were common. There were no karyotype abnormalities (17 of 22 tested). There were 4 terminations. Nine of the 18 (50%) continuing pregnancies had polyhydramnios, premature rupture of membranes, or preterm labor. The mean gestational age at birth was 36.8 weeks. One patient underwent tracheal occlusion at 27 weeks, and 2 patients died before postnatal repair. Overall survival rate (22 prenatal plus 5 postnatal diagnoses) was 19 of 27 (70%). Postnatal survival rate was 19 of 23 (83%). A Gore-tex (W. L. Gore and Associates, Flagstaff, AZ) patch was utilized in 14 of 21 neonates undergoing surgery. Twelve of 23 (52%) required extracorporeal membrane oxygenation (ECMO) with a 75% survival rate. Significant morbidity occurred in 10 of 19 survivors and included neurologic sequelae in 6 of 19 (32%).

CONCLUSIONS

MRI was helpful in the determination of liver position and confirmation of diagnosis. The high incidence of preterm complications, frequent need for ECMO, and high prevalence of comorbidities are indicative of the severity of this CDH population and warrant close prenatal surveillance and delivery at a tertiary care center with ECMO capability.

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.

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.

[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.

Lung volume, pulmonary vasculature, and factors affecting survival in congenital diaphragmatic hernia

OBJECTIVES

There is a wide variation in published mortality from congenital diaphragmatic hernia (CDH). The prevailing opinion is that this variation is related directly to the degree of pulmonary hypoplasia. Our aim was to test the hypothesis that other factors are important for outcome. The specific objectives of this study were: 1) to quantitate the degree of lung hypoplasia and pulmonary arterial wall thickness in infants eligible for, and treated with, extracorporeal membrane oxygenation (ECMO), using postmortem analysis of lung DNA, wet lung weight, lung volume, and vessel morphometrics; 2) to correlate the degree of lung hypoplasia and vascular changes with functional tests of oxygenation and estimated right ventricular systolic pressures (RVSP); 3) to determine the minimum lung volume necessary for survival; and 4) to determine contributory clinical factors as potential causes of death in ECMO-treated infants with CDH.

METHODOLOGY

We retrospectively analyzed all 90 infants with CDH admitted consecutively over a 9-year period to a children's hospital with an ECMO program. Infants were categorized as lived or died, with or without ECMO. Indication for ECMO was an evolving process; however, in general, it was the therapy of last resort for pulmonary insufficiency. Clinically, the single best oxygenation index before ECMO or CDH repair while on conventional ventilation, and serial echocardiograms before, during, and after ECMO, were obtained. Twelve of 14 infants dying with ECMO and 6 of 12 without ECMO had postmortem examinations. Lung volume, DNA content, wet weights, and arterial wall thickness at the level of alveolar ducts were measured in both lungs. Postmortem morphometric findings were correlated with in vivo tests of cardiopulmonary function and contributory clinical factors in mortality.

RESULTS

Sixty-three percent of all infants with CDH and 61% of ECMO-treated infants lived. All infants with CDH requiring ECMO had elevated RVSP/systolic systemic blood pressure ratios before ECMO (0.98 +/- 0.24). Eighty-eight percent of ECMO-treated infants with CDH decreased this ratio to < 0.5 within 14 days, regardless of lung size. However, infants dying with normal ratios still had increased arterial wall thickness and muscle in both lungs. In infants whose lung volume, DNA, and weight were > 45% of values predicted for age-matched controls, the oxygenation index ranged from 4 to 29, significantly less than that in infants with values < 45% of predicted values (range, 25 to 133). We speculate that eight infants with lung volumes > 45% of that for controls died from potentially preventable surgical and medical complications.

CONCLUSION

A minimum lung volume of 45% of the value predicted from age-matched controls is required for survival in ECMO-treated infants. The RVSP/systolic systemic blood pressure ratio can be reduced with ECMO to < 0.5 in the majority of infants, even with lung volumes inadequate for survival. We speculate that 9% of infants with adequate lung volume were potentially survivable, but died of medical and surgical complications.

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: 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.

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.

Evolution of the technique of congenital diaphragmatic hernia repair on ECMO

With the increase in popularity of delayed repair of congenital diaphragmatic hernia (CDH), many institutions are using extracorporeal membrane oxygenation (ECMO) to stabilize patients preoperatively. This practice has led to controversy regarding whether the repair should be performed while the patient is on ECMO or after decannulation. This report details the authors' experience with repair of CDH on ECMO. Of the 154 high-risk CDH patients treated at Children's Hospital, Boston, MA, since ECMO became available (1984), 97 received ECMO, including 31 who had repair performed while on ECMO. In group I (nine patients), repair was carried out only if the patients were unweanable from ECMO after 7 days. Activated clotting times (ACT) were maintained at 200 to 220 seconds. In group II (22 patients), repair was performed on ECMO electively, before decannulation. ACT were maintained at 180 to 200 seconds. Additionally, all patients in group II received aminocaproic acid before surgery. This was administered continuously for 72 hours postoperatively or until decannulation. Patients in group II had significantly less overall blood loss (P = .02), and lower transfusion requirement (P = .0003) than those in group I. Additionally, four of the nine patients in group I required reexploration because of hemorrhage; this was not required for any patient in group II (P = .005). Although the survival rates differed, this may have been because of a bias in patient selection between the two groups. From these preliminary data, the authors conclude that repair of congenital diaphragmatic hernia on ECMO can be performed safely, with a minimum of hemorrhagic complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Antenatal diagnosis of isolated congenital diaphragmatic hernia is not an indicator of outcome

It has been reported previously that infants diagnosed with congenital diaphragmatic hernia (CDH) antenatally have a much poorer prognosis than those diagnosed postnatally. The authors identified 173 high-risk (symptomatic within the first 6 hours of life) infants with CDH treated in the past decade. Seventy-seven cases were diagnosed antenatally and 96 were diagnosed postnatally. The survival rate was slightly worse for the antenatal group (34% v 48% for the postnatal group; P = .04). However, 59 of the 173 patients (34%) had other life-threatening congenital anomalies. Among the 114 patients with isolated CDH, the survival rate increased to 59% in the antenatal group and 63% in the postnatal group--a difference that was not significant. The timing of antenatal diagnosis (> or < 25 weeks) had no impact on the statistics (P = .08). The only parameter consistently different between all groups and subgroups was the Apgar score at 5 minutes, which was always better in the antenatal group (P < .02), possibly reflecting more efficient resuscitation. Of the 59 patients with other life-threatening anomalies (42 cardiac), there was one survivor among the 34 in the antenatal group and only two among the 25 in the postnatal group, despite the fact that 39 patients had undergone resuscitation, which included ECMO in 25.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

An association of pulmonary hypoplasia with unilateral agenesis of the diaphragm

During a period of 5 years, 33 newborns with congenital diaphragmatic hernia were treated. Three groups presenting with respiratory distress in the delivery room were identified. These included 8 newborns with agenesis (group 1) and 4 newborns with nonagenesis (group 2), all of whom died. There were 19 nonagenesis survivors (group 3), giving an overall survival rate of 61%. Two newborns who presented beyond 6 hours of life were excluded. No one specific arterial blood gas value or ventilation parameter obtained preoperatively could predict survival. Postmortem right and left lung weights, lung/body weight ratio, and radial alveolar counts demonstrate that agenesis is a unique subgroup with profound pulmonary hypoplasia and a dismal prognosis.

Congenital diaphragmatic hernia: long-term outcome in neonates treated with extracorporeal membrane oxygenation

As more infants with congenital diaphragmatic hernia (CDH) survive with extracorporeal membrane oxygenation (ECMO), it seems prudent to detail the longterm outcome in these medically complex infants. Eighteen children with CDH-treated with postoperative ECMO were recruited for participation in this study. The mean duration of ECMO was 193 hours (range 82 to 493 hours), mean time to extubation after ECMO was 142 hours (range 34 to 312 hours), and median duration of hospitalization was 46 days (range 30 to 181 days). Of the 18 infants, 4 (22%) were discharged home requiring oxygen therapy. At follow-up the notable findings were a high incidence of gastroesophageal reflux and failure to thrive. At both 1 and 2 years of age, 50% of infants were at less than the 5th percentile for weight. At 1 and 2 years of age, 39% and 21%, respectively, were at less than the 5th percentile for weight/length ratio. A total of 16 children (89%) had clinical evidence of reflux, and 8 (44%) were discharged home on a regimen of nasogastric feedings. Reherniation occurred in 4 children (22%) and was more frequent when a patch was used. An electrocardiogram showed right ventricular hypertrophy in 6 (43%); oxygen saturation by pulse oximetry was > 95% in all children, and pulmonary artery pressure was estimated by Doppler echocardiography to be normal in 12 of 14 children examined. The neurodevelopmental outcome (Bayley Scales or Stanford-Binet scale) at 1 to 4 years of age was not dissimilar from that of other ECMO-treated children. Given the severity of illness in the neonatal period, the general health and development of children with CDH surviving after ECMO are good. Surprisingly few children have long-term respiratory complications related to pulmonary hypoplasia. Follow-up in the first few years should be aimed at aggressive nutritional intervention to prevent the growth failure that appears to be prevalent in these children.

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

It has been suggested that delayed repair with preoperative stabilization might improve survival in high-risk (symptomatic within 6 hours of birth) congenital diaphragmatic hernia (CDH). This study compares the results of immediate operation versus delayed repair using extracorporeal membrane oxygenation (ECMO) when necessary. Since we first used ECMO in 1984, 101 high-risk CDH infants have been treated. Prior to 1987, we used immediate repair and postoperative ECMO if necessary. Between 1987 and 1990 we combined delayed operation (24 to 36 hours) with preoperative ECMO as necessary. No infant in this series was excluded from ECMO therapy unless absolute contraindications existed (prematurity, intracranial hemorrhage, or other major anomalies). Fifty-five patients received immediate operation and 46 had delayed repair. The two groups were comparable populations based on gestational age, birth weight, age at onset of symptoms, Apgar scores, best postductal PO2 (BPDPO2), and frequency of antenatal diagnosis. There was no statistically significant difference in overall survival between the two groups. Differences in survival among subpopulations (BPDPO2 greater than 100 or less than 100, antenatal diagnosis, inborn v outborn) also are not significant. The requirement for ECMO was similar in both groups. Survivors in the delayed repair group were ventilated longer and on ECMO longer, but had fewer late deaths (greater than 21 days) and fewer pulmonary sequelae (O2 dependency at discharge) than infants in the immediate repair group (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital diaphragmatic hernia: predictors of severity in the ECMO era

Infants with congenital diaphragmatic hernia (CDH) demonstrate a wide range of anatomic and physiologic abnormalities, making it difficult to compare the efficacy of new forms of therapy such as extracorporeal membrane oxygenation (ECMO) among institutions. This study was undertaken to determine whether any predictors of severity could be identified in the ECMO era. The charts of all patients with CDH treated at this institution since 1984, when ECMO became available. (n = 110), were reviewed. Infants were considered high risk and included in this study if they presented with respiratory distress within the first 6 hours of life (n = 94). In order to focus on predictors of pulmonary insufficiency, patients who died of nonpulmonary causes or had other significant congenital anomalies were excluded from this review, leaving 59 patients for analysis. All the infants during this period had intensive pharmacological and ventilatory support. When needed, ECMO was offered postoperatively from 1984 to 1987, and preoperatively from 1987 to the present. Forty-five of 59 had a best postductal PO2 (BPDPO2) greater than 100 mm Hg, and 41 of these responders survived (91%). Fourteen patients had a BPDPO2 less than 100 mm Hg and only one survived (7%) (P = .0001). Mean BPDPO2 between survivors with or without ECMO, and nonsurvivors were also significantly different (P = .001). To incorporate ventilatory information, an oxygenation/ventilation index was devised: [OVI = PO2/(mean airway pressure x respiratory rate) x 100]. Differences in OVI between these three groups were also significant. When analyzing the data by the method proposed by Bohn (PCO2 v VI), no correlation between ventilatory parameters and outcome was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of preoperative stabilization on respiratory system compliance and outcome in newborn infants with congenital diaphragmatic hernia

To determine whether preoperative stabilization and delay of operative repair of congenital diaphragmatic hernia (CDH) may decrease operative risk, we performed serial pulmonary function tests on 22 newborn infants with CDH and on four infants without pulmonary hypoplasia (two with ileal atresia and two with tracheoesophageal anomalies) who served as control subjects. We used 2 passive respiratory mechanics technique to measure respiratory system compliance. All patients with CDH had respiratory distress immediately after birth, and required mechanical ventilation. Thirteen babies underwent emergency repair (six survived, seven died); nine of them received extracorporeal membrane oxygenation (ECMO) after the operation (two survived, seven died). Operative repair was delayed deliberately for 2 to 11 days in nine infants with severe hypoxemia. Six immediately received ECMO for 4 to 10 days; one died of intraventricular hemorrhage, and five survived and later underwent surgical repair. The seventh patient did not receive ECMO but appeared to have respiratory distress syndrome of infancy and improved after administration of synthetic surfactant. Improvement was seen in two additional infants who received conventional assisted ventilation during a 48-hour delay before surgery, and survived. In all, eight of nine infants who underwent preoperative stabilization survived (p less than 0.05 compared with survival after emergency surgery). Following surgical repair immediately after birth, respiratory system compliance improved only slightly during the first week of life, a time when control infants had a rapid increase in respiratory system compliance (p less than 0.001). In contrast, respiratory system compliance increased nearly twofold in the nine patients undergoing preoperative stabilization (p less than 0.02). Preoperative ECMO was associated with an increase in respiratory system compliance of more than 60% for 1 week, a significant difference from respiratory system compliance among patients undergoing emergency CDH repair (p less than 0.05). These observations provide physiologic evidence of possible benefits of preoperative stabilization before repair of CDH.

Improvement in survival of patients with congenital diaphragmatic hernia utilizing a strategy of delayed repair after medical and/or extracorporeal membrane oxygenation stabilization

Patients with congenital diaphragmatic hernia (CDH) symptomatic at birth treated at this institution over the past 6 years were reviewed. The patients were divided into two chronological groups for analysis: group 1, consisting of 15 patients treated from January 1984 through October 1987, a period during which acute CDH was considered to be a surgical emergency; and group 2, comprising 20 patients treated from November 1987 through October 1989 using a management protocol of delayed repair following medical and/or extracorporeal membrane oxygenation (ECMO) stabilization. These two groups did not differ significantly in gestational age, birth weight, Apgar scores, hernia side, or age at admission. Group 2 had a longer mean interval from admission to repair (26.5 v 1.8 h, P = .01) and average age at repair (31.0 v 6.5 h, P = .02) than did group 1. Prosthetic closure of the diaphragmatic defect was required more frequently in group 2 then in group 1 (63% v 31%, P = .07). Survival in group 2 was significantly greater than in group 1 (55% v 20%, P = .04). Seven group 2 patients (35%) achieved a prerepair or pre-ECMO PO2 greater than 100 mm Hg and all survived; four of the 13 "nonresponders" also survived. ECMO was used in 11 group 2 patients with five survivors (45%); four of these patients underwent repair prior to ECMO and seven underwent repair while on ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of extracorporeal membrane oxygenation on survival of infants with congenital diaphragmatic hernia

To determine the effect of extracorporeal membrane oxygenation (ECMO) on the survival of infants with congenital diaphragmatic hernia, we undertook a retrospective review of 31 infants with congenital diaphragmatic hernia treated at Children's National Medical Center. Infants were categorized by means of the Bohn quadrant analysis to determine the impact of ECMO on infants with congenital diaphragmatic hernia and a "poor prognosis." All infants assigned to the Bohn 100% mortality quadrant required ECMO. The survival rate in this group was 86% (6/7) when assessed preoperatively and 67% (6/9) when assessed postoperatively. Comparison of the change occurring in ventilation index and arterial carbon dioxide pressure demonstrated that after repair the clinical condition of 48% of infants deteriorated, 40% improved, and 12% remained unchanged. Of the 12 infants whose condition was worse after surgery, 11 eventually required ECMO. Our review demonstrates that ECMO improved survival significantly in infants with congenital diaphragmatic hernia who had a "poor prognosis" by the criteria of Bohn et al. We recommend consideration of ECMO for all infants with congenital diaphragmatic hernia for whom maximal medical therapy has failed.

Extracorporeal membrane oxygenation and congenital diaphragmatic hernia: should any infant be excluded?

Mortality in infants with congenital diaphragmatic hernia (CDH) remains high despite improvements in neonatal and surgical care because many infants develop persistent pulmonary hypertension of the newborn (PPHN) following repair. Since 1984, extracorporeal membrane oxygenation (ECMO) has been used as rescue therapy in all infants (n = 25) with PPHN following CDH repair when conventional management failed, with an overall survival of 60%. Repair was performed in this hospital on 12 infants and in other hospitals in 13 infants transferred for consideration of ECMO after repair. Mortality was the same in the group repaired here and those transferred for ECMO. Although complications were frequent in the surviving group, they were successfully managed with nonoperative or operative therapy. Selective use of ECMO has been advocated in CDH patients based on various predictors of high mortality such as "best" PO2 postrepair less than 100 mm Hg, oxygenation index greater than 40, and ventilation index greater than 1,000 with PCO2 greater than 40. Seven surviving infants following ECMO would have been classified as unsalvageable by at least one parameter if selection criteria based on these parameters had been used. We conclude from this series that current predictors of high mortality in CDH patients are unreliable when ECMO is used. Surgeons caring for infants with CDH should consider the use of ECMO in all infants.

Ventilation parameters and arterial blood gases as a prediction of hypoplasia in congenital diaphragmatic hernia

Attempts to predict the degree of pulmonary hypoplasia associated with congenital diaphragmatic hernia have been made by evaluating the ventilation parameters and the arterial blood gasses of these patients. A CO2 index as a predictor of outcome, which correlates the PaCO2 with the ventilation index, was recently proposed. However, in this study the postductal PaO2 was a better predictor of survival. And the so-called "honeymoon period" was a better indicator of the efficacy of extracorporeal membrane oxygenation (ECMO) than the CO2 index. Nineteen patients were evaluated; 11 were treated with ECMO, and eight were not considered suitable for ECMO.

Fetal diaphragmatic hernia: ultrasound diagnosis and clinical outcome in 38 cases

A previously published survey has evaluated the natural history and clinical outcome of fetal diaphragmatic hernia (CDH) in 94 cases. This study showed that the prenatal diagnosis is accurate, the mortality is high (80%), and polyhydramnios is a prenatal predictor of poor clinical outcome. As a follow-up study, 38 consecutive cases of CDH diagnosed in utero were evaluated and treated by the same surgical team. This permitted detailed assessment of prognostic factors and evaluation of the impact of extracorporeal membrane oxygenation (ECMO) on outcome. We found the following. (1) Survival is poor despite optimal postnatal therapy including ECMO. (2) Polyhydramnios is both a common prenatal marker for CDH (present in 69% of fetuses) and a predictor for poor clinical outcome (only 18% survival), but tends to occur after the second trimester. (3) Amniocentesis is indicated to rule out chromosomal abnormalities that were present in 16% of fetuses. (4) All 14 fetuses diagnosed prior to 25 weeks' gestation died. Improved postnatal therapy or surgical intervention before birth will be necessary to salvage the CDH fetus with an early gestational diagnosis or associated polyhydramnios.

Congenital diaphragmatic hernia: impact of preoperative stabilization. A prospective pilot study in 13 patients

In case of congenital diaphragmatic hernia (CDH), survival generally depends not on prenatal diagnosis, planned delivery, and immediate postnatal operation, but on the gravity of pulmonary hypoplasia and persistent hypertension (PPH). Many vasoactive drugs have become available for lowering PPH, but the mortality rate for CDH still amounts to 40% to 70%. Preoperative stabilization might prevent or at least reduce the risk of PPH. This method was evaluated in a pilot study lasting 15 months and involving 13 patients. All were admitted to the pediatric surgical intensive care unit within six hours of birth, all requiring mechanical ventilation. Continuous suction of the stomach and bowel proved successful in reducing the mediastinal shift. Study parameters were alveolar-arterial oxygenation differences ((A-a)DO2), mean airway pressure (MAP), oxygenation index (OI), and ventilation index (VI), measured on admission and at set times before and after surgery. Eight patients did not survive, but in two cases death was not directly related to CDH. The following conclusions were reached: (1) satisfactory ventilation parameters on admission will remain good during the preoperative stabilization phase and will not be affected by its duration or by subsequent surgery, spelling survival; (2) unsatisfactory ventilation parameters on admission may improve with preoperative stabilization, giving these patients a better chance of survival; and (3) poor ventilation parameters on admission that fail to improve with preoperative stabilization will not improve with surgery or postoperatively, spelling death.