Mortality from neonatal diaphragmatic hernia

Survival prediction of high-risk outborn neonates with congenital diaphragmatic hernia from capillary blood gases

BACKGROUND

The extent of lung hypoplasia in neonates with congenital diaphragmatic hernia (CDH) can be assessed from gas exchange. We examined the role of preductal capillary blood gases in prognosticating outcome in patients with CDH.

METHODS

We retrospectively reviewed demographic data, disease characteristics, and preductal capillary blood gases on admission and within 24 h following admission for 44 high-risk outborn neonates. All neonates were intubated after delivery due to acute respiratory distress, and were emergently transferred via ground ambulance to our unit between 1/2000 and 12/2014. The main outcome measure was survival to hospital discharge and explanatory variables of interest were preductal capillary blood gases obtained on admission and during the first 24 h following admission.

RESULTS

Higher ratio of preductal partial pressure of oxygen to fraction of inspired oxygen (PcO2/FIO2) on admission predicted survival (AUC = 0.69, P = 0.04). However, some neonates substantially improve PcO2/FIO2 following initiation of treatment. Among neonates who survived at least 24 h, the highest preductal PcO2/FIO2 achieved in the initial 24 h was the strongest predictor of survival (AUC = 0.87, P = 0.002). Nonsurvivors had a mean admission preductal PcCO2 higher than survivors (91 ± 31 vs. 70 ± 25 mmHg, P = 0.02), and their PcCO2 remained high during the first 24 h of treatment.

CONCLUSION

The inability to achieve adequate gas exchange within 24 h of initiation of intensive care treatment is an ominous sign in high-risk outborn neonates with CDH. We suggest that improvement of oxygenation during the first 24 h, along with other relevant clinical signs, should be used when making decisions regarding treatment options in these critically ill neonates.

Malformations associated with congenital diaphragmatic hernia: Impact on survival

BACKGROUND/PURPOSE

Congenital diaphragmatic hernia (CDH) is associated with high mortality. Survival is influenced by the extent of pulmonary hypoplasia and additional congenital defects. The purpose of this study was to assess the association of congenital anomalies and admission capillary carbon dioxide levels (PcCO2), as a measure of extent of pulmonary hypoplasia, on survival in neonates with CDH.

METHODS

This is a retrospective review of neonates with CDH admitted to a tertiary neonatal intensive care unit between 1990 and 2014. Logistic regression was used to assess whether hospital survival was associated with admission PcCO2 or associated anomalies (isolated CDH, CDH with cardiovascular anomalies, and CDH with noncardiac anomalies). The probabilities of survival (POS) score, based on birth weight and 5-min Apgar as defined by the Congenital Diaphragmatic Hernia Study Group were included as a covariate.

RESULTS

Of 97 patients, 55 had additional malformations (cardiovascular n=12, noncardiac anomalies n=43). POS was lower in CDH with other anomalies compared to isolated CDH. Survival rate was 61.9%, 53.5% and 41.7% in isolated CDH, CDH with noncardiac anomalies and CDH with cardiovascular anomalies, respectively. After adjusting for POS score the likelihood of survival in CDH groups with additional anomalies was similar to isolated CDH (OR 0.95, 95% CI 0.22-4.15, and 1.10, 0.39-3.08, for CDH with and without cardiovascular anomalies, respectively). After adjusting for POS score, lower PcCO2 levels (OR=1.25 per 5mmHg decrease, P=0.003) were associated with better survival.

CONCLUSIONS

Neonates with CDH have a high prevalence of congenital malformations. However, after adjusting for POS score the presence of additional anomalies was not associated with survival. The POS score and admission PcCO2 were important prognosticating factors for survival.

Role of admission gas exchange measurement in predicting congenital diaphragmatic hernia survival in the era of gentle ventilation

BACKGROUND/PURPOSE

Neonates with significant congenital diaphragmatic hernia (CDH) require cardiopulmonary support. Management has been characterized by progressive abandonment of hyperventilation. Ability to prognosticate outcomes using measures of ventilation and oxygenation with gentle ventilation remains unclear. We sought to determine whether assessment of gas exchange at the time of NICU admission is predictive of survival in this current era.

METHODS

Neonates with CDH admitted to a Children's Hospital from 1995 to 2006 were evaluated for demographics, blood gas (ABG) measurements and ventilator settings for the first 48hours, and discharge outcome.

RESULTS

One-hundred-and-nineteen CDH patients were admitted, 88 (74%) survived. Mean admission ABG pCO2 was higher in infants who died compared to survivors (86±48 versus 49±20, p≤0.001); positive predictive value (PPV) for mortality of pCO2≥80mmHg was 0.71. Mean first hour preductal oxygen saturation (preductalO2Sat) was lower in infants who died compared to survivors (81±17 versus 97±5, p<0.001); PPV for mortality of preductalO2Sat<85% was 0.82. Eleven patients met both pCO2 and preductalO2Sat criteria, and 10 (91%) died, PPV of 0.92. Within hours of admission, pCO2 and preductalO2Sat differences between survivors and nonsurvivors lost significance.

CONCLUSION

Admission pCO2 and preductalO2Sat may be useful in predicting survival in neonatal CDH. The differential in gas exchange between survivors and nonsurvivors loses significance with contemporary neonatal care.

Modulating effect of a selective endothelin A receptor antagonist on pulmonary endothelin system protein expression in experimental diaphragmatic hernia

BACKGROUND/PURPOSE

Previously, we reported that perinatal administration of atrasentan, a selective endothelin A receptor (ETA) antagonist, provided a beneficial effect on the cardiopulmonary profile under short-term conditions in newborn lambs with surgically induced congenital diaphragmatic hernia (CDH). We hypothesized that changes in the hemodynamic profile that we observed at birth in treated animals could be influenced by pulmonary modulation of the endothelin (ET) system.

METHODS

The effect of atrasentan on protein expression levels of ETs and ET receptors (ETA and ETB receptor) was investigated by immunohistochemistry in lung tissues of untreated control (n = 3), treated control (n = 6), untreated CDH (n = 6), and treated CDH newborn lambs (n = 8).

RESULTS

Right lung tissue of treated control lambs showed significantly higher ETA protein expression levels in both vascular adventitia and airway epithelia when compared with that of untreated control lambs (P < .05). In contrast, protein expression levels of ETA and ETB receptor were significantly lower in the vascular smooth muscle cells among other tissue subcompartments of the right lung of treated CDH newborn lambs vs CDH lambs (P < .02 and P = .005, respectively).

CONCLUSIONS

We speculate that rapid pulmonary modulation of ET system protein expression levels by atrasentan results from an indirect effect possibly dependent on ventilation and/or perfusion. In CDH groups, this could contribute to the beneficial effect of the treatment.

Congenital diaphragmatic hernia: searching for answers

BACKGROUND

Pulmonary hypoplasia and hypertension are the primary causes of morbidity and mortality in infants with congenital diaphragmatic hernia (CDH). At present, the origin of CDH and the causes of pulmonary hypoplasia and hypertension are unknown.

DATA SOURCES

This article reviews the available published data regarding the origin of CDH and the pathogenesis of the associated pulmonary hypertension and hypoplasia. These investigations have employed human tissues as well as two types of CDH animal models.

CONCLUSIONS

Investigations performed to date have not yet provided definitive answers regarding the pathogenesis of CDH. However, they have yielded many new and exciting discoveries and several opportunities for intervention. Ongoing research should open new possibilities to improve the outcome for these unfortunate babies with CDH.

Evaluation of the development of lung hypoplasia in the premature lamb

BACKGROUND

The death rate from human diaphragmatic hernia (CDH) ranges from 50 to 80%, mainly due to the associated lung hypoplasia. To prevent these irreversible pathological and physical defects, the question of intrauterine surgical intervention arises. The histological changes of the lung tissue after inducement of a diaphragmatic hernia were examined. Of special interest was the time elapsing until the development of lung hypoplasia.

METHODS

A model of intrauterine inducement of diaphragmatic hernia was established using five fetal lambs to study consecutive pulmonary hypoplasia. Inducement of a diaphragmatic hernia was undertaken between 105 and 108 days' gestation. Lung tissue was examined histologically on postoperative days 8, 17, 21, 22, and 25 after inducement of the defect.

RESULTS

On postoperative days 8, 17, and 21, no signs of pulmonary hypoplasia were found on histological examination. A pulmonary hypoplasia was found in two fetuses (on the 22nd and 25th postoperative day). The pathological and anatomical examination of a unilateral pulmonary hypoplasia after a short period of time shows that the artificially created diaphragmatic defect is a good model for producing a congenital diaphragmatic hernia.

DISCUSSION

The severity of the pulmonary hypoplasia is related to the duration of lung compression by the herniated organs. The time elapsing until the development of lung hypoplasia is shorter than expected. Tracheal occlusion seems to be an effective strategy for treatment of the defect CDH, but the best technique for achieving occlusion, and particularly the ideal point in time to carry out "Fetendo," are unknown. Further research into this congenital illness is required in order to treat it.

Effect of ABT-627 (A-147627), a potent selective ET(A) receptor antagonist, on the cardiopulmonary profile of newborn lambs with surgically-induced diaphragmatic hernia

1. Postnatal mortality in isolated congenital diaphragmatic hernia (CDH) is mainly related to the associated pulmonary hypertension (PH) and to right-to-left shunting. 2. Endothelins (ETs) are potent vasoconstrictors and pro-mitogenic peptides. Strong evidences support their participation in CDH and in the etiology of PH via the activation of ET(A) receptors (ET(A)-Rs). 3. Evaluation of the effect of ABT-627, a selective non-peptidic ET(A)-R antagonist, given from -15 to 210 min post-delivery (1 mg kg(-1) bolus +0.01 mg kg(-1) h(-1) infusion, i.v.), was conducted in the lamb model of CDH. 4. Severity of CDH was assessed in comparison to untreated controls (n=5). Untreated CDH lambs (n=7) had a higher mean pulmonary arterial pressure (MPAP; P<0.0001), lower mean blood pressure (MBP; P=0.0004), higher MPAP / MBP ratio (P<0.0001), lower arterial pH (P<0.0001), higher paCO(2) (P<0.0001), lower paO(2) (P<0.0001) and lower post-ductal pulsatile SaO(2) (P<0.0001) than untreated controls. 5. Treated controls (n=7) showed a higher MPAP, lower MBP, higher MPAP/MBP ratio, lower arterial pH, higher paCO(2), lower paO(2), lower post-ductal pulsatile SaO(2) and lower plasmatic ir-ET ratios compared to untreated controls (P<0.0001). 6. Treated CDH lambs (n=8) showed a higher MBP (P<0.0001), lower MPAP / MBP ratio (P<0.0001), higher arterial pH (P<0.0001), lower paCO(2) (P<0.0001), higher paO(2) (P=0.0228), higher post-ductal pulsatile SaO(2) (P=0.0016) and lower plasmatic ir-ET ratios (P=0.0247) when compared to untreated CDH lambs. 7. These observations revealed that, although acute perinatal treatment with a selective non-peptidic ET(A)-R antagonist had some adverse effects in controls, it attenuated the progressive cardiopulmonary deterioration that occurred after birth in CDH lambs.

Heart hypoplasia in an animal model of congenital diaphragmatic hernia

PURPOSE

In previous papers, we described a new experimental model of congenital diaphragmatic hernia in rabbits, and we also reported noninvasive therapeutic strategies for prevention of the functional and structural immaturity of the lungs associated with this defect. In addition to lung hypoplasia, pulmonary hypertension, biochemical, and structural immaturity of the lungs, the hemodynamics of infants and animals with congenital diaphragmatic hernia are markedly altered. Hence, cardiac hypoplasia has been implicated as a possible cause of death in patients with congenital diaphragmatic hernia, and it is hypothesized to be a probable consequence of fetal mediastinal compression by the herniated viscera. Cardiac hypoplasia has also been reported in lamb and rat models of congenital diaphragmatic hernia. The purpose of the present experiment was to verify the occurrence of heart hypoplasia in our new model of surgically produced congenital diaphragmatic hernia in fetal rabbits.

METHODS

Twelve pregnant New Zealand rabbits underwent surgery on gestational day 24 or 25 (normal full gestational time - 31 to 32 days) to create left-sided diaphragmatic hernias in 1 or 2 fetuses per each doe. On gestational day 30, all does again underwent surgery, and the delivered fetuses were weighed and divided into 2 groups: control (non-surgically treated fetuses) (n = 12) and congenital diaphragmatic hernia (n = 9). The hearts were collected, weighed, and submitted for histologic and histomorphometric studies.

RESULTS

During necropsy, it was noted that in all congenital diaphragmatic hernia fetuses, the left lobe of the liver herniated throughout the surgically created defect and occupied the left side of the thorax, with the deviation of the heart to the right side, compressing the left lung; consequently, this lung was smaller than the right one. The body weights of the animals were not altered by congenital diaphragmatic hernia, but heart weights were decreased in comparison to control fetuses. The histomorphometric analysis demonstrated that congenital diaphragmatic hernia promoted a significant decrease in the ventricular wall thickness and an increase in the interventricular septum thickness.

CONCLUSION

Heart hypoplasia occurs in a rabbit experimental model of congenital diaphragmatic hernia. This model may be utilized for investigations in therapeutic strategies that aim towards the prevention or the treatment of heart hypoplasia caused by congenital diaphragmatic hernia.

Estimating disease severity of congenital diaphragmatic hernia in the first 5 minutes of life

BACKGROUND/PURPOSE

Congenital diaphragmatic hernia (CDH), occurring approximately once in every 2,400 live births, remains a significant cause of perinatal death and morbidity. Risk assessment tools for congenital diaphragmatic hernia derived at single institutions fail to predict outcome at other institutions. Without a generally applicable risk assessment tool it is impossible to determine whether the current variation in outcomes is caused by differences in treatment or to variations in the types of patients treated. The authors report a broadly applicable risk assessment tool for newborns with CDH derived from multiinstitutional data.

METHODS

Survival data on 322 consecutive liveborn infants with CDH were collected using data from 71 institutions. Demographic and early treatment results were evaluated by univariate analysis. Items useful in an early stratification system were examined using a multivariate logistic regression analysis. The predictive equation developed was applied to the next series of evaluable patients.

RESULTS

A total of 1,054 patients with CDH were evaluated from 1995 to 1999 with an overall survival rate of 64%. For the first 322 patients, factors associated with outcome included birth weight, Apgar scores, gestational age, race, immediate distress, presence of a cardiac anomaly, and prenatal diagnosis. Multivariate analysis showed that birth weight and 5-minute Apgar scores were most useful in a predictive equation. A logistic equation using these 2 variables could separate the next 673 patients into high, intermediate, and low risk of death, and this correlated closely with the actual outcome.

CONCLUSION

Stratifying neonates with CDH into broad risk groups should allow better comparison of outcomes data from different centers, reserving novel and high-risk strategies for patients with a high likelihood of dying.

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.

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

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

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

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

Structural chromosome anomalies in congenital diaphragmatic hernia

In order to determine the outcome and associated chromosomal and structural anomalies in fetuses diagnosed in utero as having a congenital diaphragmatic hernia, we reviewed 48 consecutive cases referred to our regional Fetal Diagnostic Unit between 1988 and 1995. All babies were delivered in units with appropriate neonatal resuscitation facilities. Thirteen babies [34 per cent of those tested, confidence interval (CI) 19-49 per cent] had karyotypic abnormalities. Three had trisomies but the other nine had more complex karyotypic abnormalities including translocations, deletions, and marker chromosomes. Twenty-one fetuses (44 per cent, CI 30-58 per cent) had additional ultrasound abnormalities which affected the heart in ten cases (21 per cent). Overall, 13 babies survived (27 per cent, CI 14-40 per cent). In babies with normal chromosomes and no additional structural abnormalities the survival rate was 50 per cent (CI 25-75 per cent). Poor outcome was not predicted by early gestation at diagnosis, the hernial contents, or the presence of polyhydramnios. We conclude that parents should be counselled about prognosis with information derived from series of prenatally diagnosed diaphragmatic hernias. The investigations offered should include a detailed ultrasound examination, particularly of the heart, and karyotyping by fetal blood sampling.

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

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

Effect of extracorporeal life support on survival when applied to all patients with congenital diaphragmatic hernia

Extracorporeal life support (ECLS) has been used for neonates with congenital diaphragmatic hernia (CDH) and respiratory failure at the authors' hospital since June 1981. In 1988, criteria for inclusion in ECLS were broadened to include "nonhoneymoon" infants (honeymoon: best postductal PaO2 of > 50 mm Hg). To evaluate the impact of this approach on the treatment of CDH, the authors reviewed the records of all newborns managed at their institution, since the availability of ECLS in 1981, who were symptomatic with CDH in the first 24 hours of life (n = 111). The patients were divided chronologically into two groups: 1981 to 1987 (early ECLS, n = 36) and 1988 to 1993 (expanded ECLS, n = 75). The data demonstrate that the number of CDH patients managed at our institution each year has increased (1981 to 1987 = 6, 1988 to 1993 = 14) as has the severity of associated respiratory insufficiency (% of patients with best PaO2 of < or = 50 mm Hg: 1981 to 1987 = 6%, 1988 to 1993 = 28%). Overall, the survival rate was lower for patients in the expanded ECLS group (59% v 75%; P = .121). When the survival rates for patients supported with ECLS postoperatively were compared for the expanded and early groups, a significant difference (59% v 80%; P < .05) was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrofen-induced congenital diaphragmatic defects in CD1 mice

In previous clinical reports, we have documented the association of several morphologic changes with congenital diaphragmatic hernia or, perhaps more appropriately termed, congenital diaphragmatic defect (CDD). These anomalies include decreased cardiac mass with left ventricular hypoplasia in infants with left-sided CDDs (Siebert et al., '84), enlarged, asymmetric chests (Siebert and Benjamin, '87), and extrathoracic anomalies (Benjamin et al., '88), including urinary tract anomalies and elevated kidney weights in otherwise normal kidneys (Glick et al., '90; Siebert et al., '90). Hypoplastic lungs and hearts and enlarged chests are thought to result from the herniation of abdominal viscera into the thoracic cavity, but for the renal abnormalities, pathogenesis is unclear. The findings are intriguing, for they could mirror unrecognized developmental relationships between the diaphragm, lung, heart, and kidney. In order to further examine these issues and to test the applicability of experimentally produced CDDs to human disease, we administered nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether), an herbicide known to produce diaphragmatic defects in rodents, to time-mated CD1 mice by gavage feeding on gestational days 8 and 9. Dosages were 200 (low dose) or 500 (high dose) mg/kg body weight, and fetuses were studied on gestational day 18. Diaphragmatic defects occurred in a dose-response fashion: 0% (0/48) control or sham-fed, 5% (5/104) in the low-dose group, and 25% (19/75) in the high-dose group. Several fetuses with cleft palate, renal agenesis, exencephaly/encephalocele, and/or Di-George sequence were noted at the high dose, the latter a previously undescribed finding. Diaphragmatic defects were primarily right sided and only associated with herniation of abdominal viscera in animals exposed to 500 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed surgical repair and ECMO improves survival in congenital diaphragmatic hernia

One hundred ten infants with congenital diaphragmatic hernia (CDH) developed life-threatening respiratory distress in the first 6 hours of life. Associated anomalies were present in 33%. Twenty-eight of 65 infants (43%) treated before 1987 (pre-extracorporeal membrane oxygenation [ECMO] era) survived after immediate CDH repair, and mechanical ventilation with or without pharmacologic support. Only two of 16 (12.5%) infants requiring a prosthetic diaphragmatic patch survived. Since 1987, 31 of 46 (67.4%) infants with birth weight, gestational age, and severity of illness similar to the pre-1987 group survived. All patients were immediately intubated and ventilated. Seven (four with lethal chromosomal anomalies) infants died before treatment, and 30 stabilized (partial pressure of carbon dioxide [PCO2] < 50; partial pressure of oxygen [PO2] > 100; pH > 7.3) and underwent delayed CDH repair at 5 to 72 hours. Fifteen did well on conventional support and survived. Fifteen infants deteriorated after operation: 11 were placed on ECMO with eight survivors, and four infants were not considered ECMO candidates. Nine babies failed to stabilize initially and were placed on ECMO before CDH repair (alveolar-arterial gradient > 600 and oxygenation index > 40), and seven survived. The overall survival rate was 80% at 3 months in this ECMO-treated group. Early mortality was due to inability to wean from ECMO (one), intracranial hemorrhage (one), liver injury (one), and pulmonary hypoplasia (one). Nine of 11 babies requiring a prosthetic patch in the post-1987 ECMO group survived (81.8%). There were three late post-ECMO deaths (3 to 18 months) of right heart failure (two) and sepsis (one). Symptomatic gastroesophageal reflux occurred in nine cases, six requiring a fundoplication in the bypass babies. Recurrent diaphragmatic hernia occurred in nine cases (five ECMO). The overall survival rate was significantly improved in the delayed repair/ECMO group (67% versus 43%; p < 0.05) and was most noticeable in infants requiring a prosthetic diaphragm (81.2% versus 12.5%; p < 0.005). These data indicate that early stabilization, delayed repair, and ECMO improve survival in high-risk CDH. Early deaths are related to pulmonary hypertension and can be reversed by ECMO.

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)

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.

Pulmonary hypertension in lambs with congenital diaphragmatic hernia: vasodilator prostaglandins, isoprenaline, and tolazoline

After antenatal induction of diaphragmatic hernias in fetal lambs, prostaglandins D2, E1, and I2 were compared to tolazoline, or isoprenaline, for the treatment of pulmonary hypertension. When rendered hypoxic, these, and normal lambs, showed an increase in pulmonary artery pressure, a decrease in systemic pressure, and a decrease in pulmonary blood flow. All of the drugs altered that response, but to different degrees. None of the drugs tested was consistently successful in reversing the adverse affects of hypoxia, but prostaglandin D2 came closest to the ideal vasodilator, decreasing the pulmonary artery pressure in all seven hypoxic lambs having a diaphragmatic hernia. There was a concomitant increase in pulmonary blood flow in six; in the remaining lamb the decrease in blood flow induced by the hypoxia was arrested. At the same time, there was an increase in systemic artery pressure in three, the decrease was arrested in two, but the decrease continued in the other two. Isoprenaline was a more effective drug than tolazoline, producing an increase in pulmonary blood flow in five of the seven lambs, with minor decreases in systemic pressure in five. Tolazoline improved blood flow in three of six lambs (not all lambs survived the full study), with a marked decrease in systemic pressure in four of them. Prostaglandin D2 seems to be a useful drug for the treatment of patients having diaphragmatic hernias and pulmonary hypertension, and warrants further study. Isoprenaline was the most effective of the readily available drugs tested in this animal model.

Non-immune hydrops fetalis: rapidity of onset and usefulness of prenatal ultrasonography

Non-immune hydrops fetalis (NIHF) has become more common than immune hydrops fetalis as a cause of fetal hydrops and its contribution to the total perinatal mortality rate has increased from 0.1% to 3.0% for the 10 years to 1979. A case is reported where an antenatal ultrasonograph performed within 24 hours of delivery showed hydrops was not present, however, at birth the infant was grossly hydropic and died despite intensive management. This case shows the rapidity of onset of NIHF and the devastating effect of this disorder. A review of two large series of NIHF revealed that in only 11.4% and 16.3% respectively, a significant uncorrectible associated major malformation may have been missed by antenatal ultrasonography. Hence, if prenatal ultrasonography fails to reveal a major malformation a viable fetus with NIHF should be regarded as salvageable. Pulmonary hypoplasia occurred in over 90% and is probably due to compression from serous cavity effusions. Thus to improve survival the ultrasonographer needs to watch for the development of serous cavity effusions so that a pregnancy complicated by NIHF can be terminated before the fetus develops pulmonary hypoplasia.

Use of the postductal PaO2 as a predictor of pulmonary vascular hypoplasia in infants with congenital diaphragmatic hernia

Infants with congenital diaphragmatic hernia (CDH) demonstrate a wide range of anatomic and physiologic abnormalities that result in decreased pulmonary perfusion. We have used the patients' ability to achieve at least one postductal PaO2 greater than 100 torr while on maximal ventilation with 100% oxygen during the first 24 hours of life as the clinical marker to identify the degree of pulmonary perfusion. Patients were grouped as follows: group 1 had at least one postductal PaO2 greater than 100 torr, and group 2 patients never had a postductal PaO2 above 100 torr. To see if this classification did reflect pulmonary vascular abnormalities, we compared the pulmonary arteriograms of these two groups of CDH infants for size of the main pulmonary arteries (PAs), size of the lungs, and degree of peripheral vascular obstructive disease (PVO). Infants in group 2 had significantly smaller ipsilateral and contralateral main PAs, as well as smaller ipsilateral lungs with more severe PVO. We propose the postductal PaO2 as the clinical marker for identification of the degree of pulmonary perfusion.

Unilateral agenesis of the diaphragm

During a period of 4 1/2 years, 37 infants with congenital diaphragmatic hernia were treated. The overall survival rate was 68%. Survival depended more on cardiopulmonary function than the size of the diaphragmatic defect. There was little evidence that infants with agenesis of the diaphragm formed a special group with a poor prognosis, and four of the ten patients with unilateral agenesis survived. A Dacron prosthesis is recommended as a substitute for the missing diaphragm.

Ventilatory predictors of pulmonary hypoplasia in congenital diaphragmatic hernia, confirmed by morphologic assessment

We carried out a prospective study in 66 infants with congenital diaphragmatic hernia within the first 6 hours of life to determine whether outcome is related to the degree of underlying pulmonary hypoplasia, as predicted by preoperative PaCO2, when correlated with an index of ventilation (VI = mean airway pressure X respiratory rate) and confirmed by postmortem analysis of the lung. Those infants with PaCO2 greater than 40 mm Hg before surgery had a 77% mortality; when PaCO2 reduction could be achieved only with VI greater than 1000, the mortality was still greater than 50%. After repair, however, the ability to hyperventilate to PaCO2 less than 40 mm Hg proved to be an important determinant of survival; only one of 31 infants in this group died, whereas only two of 27 infants with PaCO2 greater than 40 mm Hg survived. In 16 infants with PaCO2 greater than 40 mm Hg despite hyperventilation, high-frequency oscillatory ventilation was started. This resulted in a rapid fall in PaCO2, but 14 of the 16 infants had only temporary improvement in oxygenation, and died. In five of the infants who died, alveolar number was assessed by postmortem morphometric analysis; there was a severe reduction to less than 10% of published normal neonatal values. Pulmonary vascular changes of increased muscularization were less remarkable than those observed in infants with persistent pulmonary hypertension. Our findings suggest that the degree of pulmonary hypoplasia (which would not be influenced by surgical repair), rather than the pulmonary vascular abnormality, mainly determines survival. Consideration could therefore be given to an initial nonsurgical approach to congenital diaphragmatic hernia, with the expectation that pulmonary function might improve and pulmonary vascular resistance decrease.

Chest size and symmetry in congenital diaphragmatic hernia

Infants with congenital diaphragmatic hernia have significantly increased chest circumferences. This implies that intrathoracic volumes are increased as well. Forces produced by the herniated abdominal viscera seem to provide the chief impetus for this change. Other factors may also contribute, for thoracic enlargement is asymmetric and not always ipsilateral to the hernia. The contribution of an enlarged chest to respiratory insufficiency, persistence of the fetal circulation, and hyperinflation is not fully understood, but may have relevance in evaluating new approaches to therapy.

Pulmonary barotrauma in congenital diaphragmatic hernia: experimental study in lambs

A left diaphragmatic hernia was created surgically in 20 fetal lambs between 93 and 110 days of gestation. Ten animals were alive with defects at cesarean section near term (135 to 140 days). These animals and two controls were submitted to various transpulmonary pressure gradients (inspiratory pressure minus pleural pressure). Hemodynamic and ventilatory studies were performed after the correction of the hernia. Morphometric analysis of the lung was carried out in all cases. The results showed a highly significant linear correlation between the transpulmonary pressure gradient employed and the pulmonary interstitial emphysema found at morphometry. Our data suggest that using low ventilatory pressures and not draining the pleural cavity results in less trauma to both lungs and may prevent one of the components of the pulmonary hypertension so often seen in newborns with congenital diaphragmatic hernia.

Present status of intrauterine treatment of hydrocephalus and its future

At a time when the intrauterine diagnosis of hydrocephalus is common and pioneering efforts of antenatal therapy are evolving, an assessment of intrauterine treatment of this disorder becomes pertinent. Consequently, the current status of the intrauterine treatment of fetal hydrocephalus is presented. The new data from the International Fetal Surgery Registry at the University of Manitoba in Winnipeg are discussed. The technical problems of antenatal shunting, the clinical trials, and experimental treatment are assessed. The prognostication and possible new approaches in intrauterine treatment of hydrocephalus are presented as well as the new diagnostic and surgical techniques. The outcome of the antenatal diagnosis and treatment of fetal hydrocephalus is evaluated.

Congenital diaphragmatic hernia

Congenital diaphragmatic hernia continues to be a critical problem in neonatal surgery. Despite the apparent simplicity of the anatomic defect, the physiology is complex, and survival remains uncertain. Surgical success has been achieved, but we recognize that the barrier to survival is pulmonary parenchymal and vascular hypoplasia as well as the complex syndrome of persistent fetal circulation. In many ways the problem of diaphragmatic hernia is as much of an enigma to today's physician-scientist as it was to Bochdalek in the nineteenth century. The treatment of respiratory distress after repair of congenital diaphragmatic hernia has brought out the most creative and innovative efforts of pediatric surgeons in both the laboratory and the intensive care unit.

Prenatal diagnosis and natural history of the fetus with a congenital diaphragmatic hernia: initial clinical experience

To study the accuracy of prenatal diagnosis and define the natural history of fetal congenital diaphragmatic hernia (CDH), we reviewed experience with CDH at The University of California, San Francisco (UCSF) over the last three years. All nine babies born in our institution (inborns) and six of 11 babies referred from other hospitals after birth (outborns) died, an overall mortality of 75%. All had pulmonary hypoplasia. Forty percent had associated malformations or chromosomal abnormalities, a higher incidence than generally reported. Prenatal sonograms were available in all nine inborn cases. CDH was correctly diagnosed prospectively in only five, but could be recognized retrospectively in all nine cases using the sonographic criteria developed from the study. Polyhydramnios was present in all nine cases; in seven cases sonography was performed because the woman was large-for-dates clinically. There were no false positive interpretations, and when necessary the diagnosis was confirmed by amniography. All nine cases of CDH detected in utero died. Seven deteriorated so rapidly that surgical repair could not even be attempted. Two who had optimal care (maternal transport, immediate resuscitation and operation) died after repair despite maximal intensive care including vasodilator therapy. Despite the theoretical advantages of maternal transport to pediatric surgical specialty centers, a majority of fetuses with a prenatal diagnosis of CDH will die because their lungs are inadequate to support extra-uterine life even at term.

The relationship between PaCO2 and ventilation parameters in predicting survival in congenital diaphragmatic hernia

Fifty-eight infants with congenital diaphragmatic hernia presenting within the first 6 hours of life, who underwent surgical repair, were analysed prospectively in order to produce a reliable index of severity of disease that would reliably predict eventual outcome. All were treated with paralysis hyperventilation and intravenous (IV) isoproterenol for the first 48 hours. There were 30 survivors and 28 deaths in this series (mortality 48%). Using arterial PCO2 values measured 2 hours after surgical repair and correlating them with an index of mechanical ventilation (mean airway pressure and respiratory rate), we have been able to clearly define two groups of diaphragmatic hernia based on their response to IPPV. The first group, with CO2 retention and severe preductal shunting, was unresponsive to hyperventilation with high rates and pressures; the mortality was 90%. The second group responded well to hyperventilation and demonstrated reversable ductal shunting only. Survival in this group was 97%. Only four patients out of 58 exhibited the "honeymoon period," with a period of stability followed by severe ductal shunting. Arterial CO2 accurately reflects the degree of lung development in this disease and separates those patients with severe pulmonary hypoplasia, where the outcome is invariably fatal, from those with a well-developed contralateral lung where there is excellent potential for survival.

Left ventricular hypoplasia in congenital diaphragmatic hernia

Quantitative anatomic study of the hearts of eight infants with left-sided congenital diaphragmatic hernia (CDH) has revealed significantly decreased cardiac mass, due to hypoplasia of the left atrium and ventricle and interventricular septum. These morphologic deficiencies may be a result of compression of mediastinal structures by herniated abdominal viscera during prenatal life. Left ventricular hypoplasia is likely to be an important factor in the pathogenesis of cardiac insufficiency in patients with left CDH.

Alveolar-arterial oxygen gradients versus the Neonatal Pulmonary Insufficiency Index for prediction of mortality in ECMO candidates

Current selection criteria necessary for intelligent application of extracorporeal membrane oxygenation (ECMO) in hypoxic neonates remains controversial. Both the Neonatal Pulmonary Insufficiency Index (NPII) and serial alveolar-arterial oxygenation gradient measurements (A-a)Do2 have been recommended. Accordingly, an analysis of 50 consecutive severely hypoxic neonates was undertaken to assess the predictive value of (A-a)Do2 determinations and NPII in discriminating survivors from non-survivors. These infants with meconium aspiration syndrome (MAS), congenital diaphragmatic hernia (CDH), or persistent pulmonary hypertension of the newborn (PPHN) required maximum mechanical ventilation for hypoxia. Pharmacologic manipulation of pulmonary vascular resistance was attempted in 83%. If postductal (A-a)Do2 remained greater than or equal to 620 torr despite 12 hours of maximum medical therapy, mortality was 100%; however, 35% of nonsurvivors were unfortunately excluded. (A-a)Do2 greater than or equal to 600 torr for 12 hours demonstrated 93.8% mortality, and only 12% of all mortalities were thus excluded. Among nonsurvivors successfully hyperventilated, the NPII could not predict mortality. Ideal selection criteria must exclude those who would otherwise survive without ECMO, yet allow early accurate identification of the neonate certain to die. It would appear that serial (A-a)Do2 determinations best permit this identification and thus orderly application of ECMO.

The advantages of reconstruction of the dome of the diaphragm in congenital posterolateral diaphragmatic defects

Repair of a congenital posterolateral diaphragmatic defect (CPLDD) by direct suture results in a flat drum-head diaphragm, which has very little function. Other harmful effects of such a repair include enlargement of the thoracic cavity, resulting in more overexpansion of the hypoplastic lungs which may contribute to pulmonary vascular obstruction, and decrease in volume of the abdominal cavity, making closure of the laparotomy difficult. Reconstruction of a diaphragmatic dome would result in a more functional diaphragm and would prevent the above complications. This was substantiated in a series of 10 babies, all severely symptomatic from birth and treated according to the proposed technique. Eight babies survived, the two deaths occurring 36 hours and 3 months after surgery, in babies with severe cardiac anomalies. It is concluded that reconstruction of the dome of the diaphragm in patients with a CPLDD is well tolerated and may result in an increased survival.

The "critical" neonate with diaphragmatic hernia: a 21-year perspective

We have seen a modest improvement in the survival of a homogeneous group of critically ill newborns with congenital diaphragmatic hernia since 1979. Twenty-seven "critical" infants have been treated who developed respiratory distress shortly after birth, required urgent resuscitation, and could not be stabilized before operation. Two died with other anomalies that appeared incompatible with prolonged survival. Ten of the 27 lived. This survival contrasts with that of only two of 17 similarly affected babies treated from 1962 to 1978. In addition, there has been no operative mortality outside of this "critical" group since 1979; whereas six noncritical babies died between 1967 to 1978. Our current therapeutic plan includes the early establishment of a respiratory alkalosis and vasodilator therapy before or during transport. Postoperatively we have attempted to maintain the baby's arterial pH greater than 7.5, Pco2 less than 25 to 30 and the PO2 approximately 150 torr. The most effective ventilatory parameters have been a rate of 130, PEEP of 5 and an inspiratory:expiratory ratio of 1:1. Peak airway pressures are kept as low as possible. Pharmacologic and ventilator therapy are weaned slowly, and intensive support has been required for at least 48 hours in each baby. Retained secretions and atelectasis of the hypoplastic lung persisted for two to several weeks postoperatively. Two babies that are one year or older still appear to have severely hypoplastic lungs on chest x-ray. M-mode echocardiography has been used to measure ventricular ejection periods. The right ventricular systolic time interval correlates with the degree of pulmonary hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

A preoperative x-ray scoring system for risk assessment of newborns with congenital diaphragmatic hernia

The survival rate for newborn infants with congenital diaphragmatic hernia (CDH) is about 50%. The preoperative x-rays of 34 babies with CDH, presenting during the first 12 hours of life were reviewed to determine whether or not the 16 survivors (47%) might be identified. A scoring system using five roentgen findings having a significant correlation with survival (side of diaphragmatic hernia, location of stomach, presence of pneumothorax, relative volume of aerated ipsilateral and contralateral lung) were summed to obtain a total x-ray score. Cumulative scores ranged from 2 to 9 with 4 of 16 survivors (25%) and 16 of 18 (89%) non-survivors scoring above 6. Twelve of 16 (75%) survivors and 2 of 18 non-survivors (11%) (P less than 0.005), scored 6 or less. Individual x-ray findings were less specific in predicting outcome than the total score. Careful examination of the preoperative chest x-ray may give the surgeon an additional method for predicting outcome following repair of CDH during the first 12 hours of life.

Lethal nonpulmonary anomalies associated with congenital diaphragmatic hernia: implications for early intrauterine surgery

Recently, interest has been expressed in the correction of diaphragmatic hernia in utero as a solution to the problem of high mortality from this condition. Before such a procedure can be adopted in the human, studies aimed at establishing the contribution such advanced techniques would make in reducing mortality are required. Between 1973 and 1982, there were 36 cases of congenital diaphragmatic hernia among 75,512 births--an incidence of 1 in 2097 births. there were 11 (31%) stillbirths and 25 (69%) livebirths. the liveborn patients were divided into two groups: group A included 15 patients who died prior to transfer to the referral center; group B included ten neonates who arrived at the referral center and were operated upon. Twenty (56%) cases of diaphragmatic hernia (11 stillbirths and 9 liveborns who did not live long enough to be transferred to the referral center) were found to have lethal nonpulmonary associated anomalies at autopsy. In view of the high association of lethal anomalies it appears that fetal surgery would have a limited role in reducing mortality in congenital diaphragmatic hernia.

High-frequency ventilation at rates of 375 to 1800 cycles per minute in four neonates with congenital diaphragmatic hernia

Neonates with congenital diaphragmatic hernias (CDH) often die because of pulmonary hypoplasia and high pulmonary vascular resistance (PVR). Pulmonary hypertension and right-to-left shunting precedes progressive hypoxia and death. PVR is increased by acidosis and by high airway pressures. High-frequency oscillation (HFO) is a new technique which may improve the outcome for such infants. Gas exchange in HFO is achieved by directing rapid pulsations of small volumes of gas down the trachea, typically at rates greater than 200 cycles per minute, volumes less than 25% of dead space, and low airway pressures. Gas transport results from augmented diffusion, not from bulk flow. Four neonates with CDH deteriorated on conventional mechanical ventilation and required hand ventilation at rates above 200 per minute. HFO at frequencies from 375 to 1800 cycles per minute was then initiated using a flow-interrupter type of oscillator. A marked fall in PaCO2 and a rise in pH resulted. The elimination of CO2 was very efficient with low mean airway pressures (less than 15 mm Hg). The initial improvement during HFO probably resulted from a decrease in PVR due to reversal of the acidosis. However, all four babies died after 13 to 80 hours of HFO. Neonates with CDH who remain hypercapneic despite conventional mechanical ventilation can be successfully ventilated by HFO. Use of HFO produces respiratory alkalosis which may stabilize PVR in the normal range and improve survival rate.

Iatrogenic pneumothorax and mortality in congenital diaphragmatic hernia

In a review of 22 infants who underwent surgical repair of congenital diaphragmatic hernias, it was noted that one of the most common factors correlating with death was perioperative tension pneumothorax. Each of the seven infants who died developed an iatrogenic pneumothorax with air leak due to face-mask or endotracheal ventilation with pressures in excess of 34 cm H2O, or to thoracentesis. Only two infants with tension pneumothorax survived. Infants who developed tension pneumothorax experienced severe respiratory distress at an earlier age and required more vigorous resuscitative measures than those infants without an air leak.

Reversion to fetal circulation in congenital diaphragmatic hernia: a preventable postoperative complication

A review of 26 patients with congenital diaphragmatic hernia, diagnosed in the first 24 hours of life, supports the hypothesis that the postoperative fetal circulation syndrome is an iatrogenic complication, due to the rapid expansion of both lungs, when they are severely hypoplastic. This complication is preventable, when no aspiration of air from the chest cavity is done, and when no tube attached to an underwater seal is inserted. When assisted ventilation is necessary, small volumes at a rapid rate allows satisfactory gaseous exchanges, without pulmonary overinflation.

Non-immune hydrops fetalis: changing contribution to perinatal mortality

During the decade to 1979, 203 hydropic infants died in the State of Victoria, Australia. Non-immune hydrops fetalis (NIHF) became more common than immune hydrops fetalis as a cause of fetal hydrops, and its contribution to the total perinatal mortality increased from 0.1% to 3%. The perinatal mortality rate of infants with NIHF was virtually 100%. The most consistent finding at post-mortem was pulmonary hypoplasia which was probably due to compression from serous cavity effusions. Survival may be improved by early diagnosis and termination of the pregnancy in selected patients with viable infants before the development of gross serous cavity effusions. The most constant clinical sign associated with hydrops fetalis was polyhydramnios which is an indication for ultrasonography and cardiotocography to detect cases of NIHF and to select the optimum time for delivery.

Management of neonatal posterolateral diaphragmatic hernia

From March 1978 to April 1982 13 neonates with a left posterolateral diaphragmatic hernia were seen in respiratory distress within 12 hours of birth. Each had severe acidosis and hypoxia. They were immediately intubated and ventilated. Arterial and central venous lines were inserted, the acidosis was partially corrected, and a dopamine infusion of 4-8 micrograms/kg/min was begun immediately. Continuous monitoring of arterial and venous pressures, core and skin temperatures, blood gases, and pH was instituted. Diaphragmatic defects were repaired by direct suture in nine neonates and by Gore-Tex patches in four. The left lung in all patients was hypoplastic. Ventilation and inotropic support were continued for four to five days after operation and close control of acid-base balance was maintained. All but one survive and are doing well. We consider the key to survival to be management of the dangerous combination of acidosis (by enhancing peripheral and renal perfusion with dopamine) and hypoxia (by prolonged assisted ventilation).

Incarcerated congenital diaphragmatic hernias with bowel obstruction (Bochdalek)

Incarcerated congenital diaphragmatic hernias are a rare cause of bowel obstruction in children. In the past 3 yr, we have treated three such diaphragmatic hernias: the first incarcerated and strangulated requiring bowel resection while the other two were incarcerated only. The difficulty in diagnosing this condition in illustrated by these cases. In all children with the triad of upper respiratory illness (URI) or infiltrate on chest x-ray, vomiting, and x-ray evidence of bowel obstruction, the diagnosis of congenital diaphragmatic hernia (CDH) with incarceration and bowel obstruction should be entertained.

Clinical use of an extracorporeal membrane oxygenator in neonatal pulmonary failure

Pulmonary failure is the most frequent cause of mortality in newborns, accounting for 15,000 deaths yearly. It may be the result of the respiratory distress syndrome (RDS), meconium aspiration syndrome (MAS), or persistent fetal circulation (PFC), including infants with congenital diaphragmatic hernia (CDH). Early identification of patients with predictably fatal but potentially reversible respiratory failure refractory to conventional management protocols would permit orderly application of extracorporeal membrane oxygenation (ECMO) as a final resuscitative measure. Eight neonates with severe pulmonary failure manifested by A-a DO2 of greater than 620 torr for greater than 12 hr, persistent cardiovascular instability, and relentless progression of acidosis and hypoxemia were predicted to have a 100% mortality in spite of maximal medical therapy. Four patients presented with MAS and 4 others had PFC, including 2 with CDH. All were supported with ECMO using the internal jugular vein and common carotid artery for access to the right atrium and aortic arch. Following support for 77-313 hr, 6 were successfully weaned from ECMO and then from the ventilator. In these few patients the use of extracorporeal membrane oxygenation after exhaustion of standard therapy was accomplished safely and successfully without untoward short-term sequelae. Extracorporeal ventilatory support may purchase the critical time necessary for resolution of the underlying parenchymal disease, including the pulmonary hypertension associated with CDH.

The management of neonatal posterolateral diaphragmatic hernia

Between March, 1978, and August, 1980, 7 neonates with a left posterolateral diaphragmatic hernia were seen in respiratory distress within 12 hours of birth. Each had severe acidosis and hypoxia. They were immediately intubated and ventilated. Arterial and central venous lines were inserted, the acidosis was partially corrected, and a dopamine infusion of 5 microgram/kg/min was begun immediately. Continuous monitoring of arterial and venous pressures, core, and skin temperatures, blood gases, and pH was instituted. Diaphragmatic defects were repaired by direct suture in 5 neonates and by Gore-Tex patches in the other 2. The left lung in all patients was hypoplastic. Ventilation and inotropic support were continued for 4 to 5 days post-operatively, and close control of acid-base balance was maintained. All the patients are doing well. We consider the key to survival to be management of the dangerous combination of acidosis (by enhancing peripheral and renal perfusion with dopamine) and hypoxia (by prolonged assisted ventilation).

Correction of congenital diaphragmatic hernia in utero. III. Development of a successful surgical technique using abdominoplasty to avoid compromise of umbilical blood flow

Infants born with congenital diaphragmatic hernia (CDH) die because their lungs are hypoplastic. In the fetal lamb, the lung made hypoplastic by compression with an intrathoracic balloon can, if decompressed in utero, grow and develop enough to permit survival at term. To study the efficacy and feasibility of in utero repair of CDH, we created diaphragmatic hernias in fetal lambs at approximately 100 days gestation and corrected them surgically at approximately 120 days. Repair of the diaphragm with closure of the abdomen resulted in postoperative fetal death in six lambs. Acute studies demonstrated that increased intraabdominal pressure compromises blood flow in the umbilical vein and produces severe fetal distress. When a silastic patch was used to enlarge the abdomen after reduction of the viscera and repair of the diaphragm, six of nine lambs were viable after term delivery. In sacrificed lambs, the lungs were well expanded, mature histologically, and greatly increased in size. Correction of CDH in utero appears physiologically sound and technically feasible.

Congenital diaphragmatic hernia

Surgical intervention for congenital diaphragmatic hernia is urgent, but success depends more on preoperative and postoperative management of the associated physiologic derangements. Survival seems to depend on the condition of the lungs at birth. In the future, correction of congenital diaphragmatic hernia in utero may be possible.

Tolazoline in the treatment of congenital diaphragmatic hernias

Four babies with congenital diaphragmatic hernias each developed a state of transitional circulation. Tolazoline was successfully used to lower the pulmonary vascular resistance and to treat this normally fatal postoperative complication.