Iatrogenic pneumothorax and mortality in congenital diaphragmatic hernia

Comparison of Clinical Endotracheal Tube Depths with Standard Estimates for the Stabilization of Infants with Congenital Diaphragmatic Hernia

OBJECTIVE

 This study aimed to compare the clinical endotracheal tube (ETT) depth after initial stabilization of infants with congenital diaphragmatic hernia (CDH) to weight and gestational age-based depth estimates.

STUDY DESIGN

 This retrospective analysis included 58 inborn infants with left-sided CDH. We compared a standard anatomic ETT depth calculated from initial chest radiographs and the clinical depth of the ETT after adjustments to predicted depths using weight and gestational age-based estimates.

RESULTS

 The standard anatomic depth was deeper than age (standard deviation 1.29 ± 1.15 cm, p < 0.001) and weight-based (standard deviation 0.59 ± 0.95 cm, p < 0.001) estimates. The clinical ETT depth was also deeper than age (standard deviation 1.01 ± 0.77 cm, p < 0.001) and weight-based (standard deviation 0.26 ± 0.50 cm, p < 0.001) estimates.

CONCLUSION

 Established strategies to predict ETT depth underestimate the ideal depth in infants with left-sided CDH. These data suggest utilizing caution during initial ETT placement based on standard depth estimates for patients with CDH.

KEY POINTS

· CDH patients present unique stabilization challenges.. · Standard ETT depth estimates are too shallow.. · Resuscitation teams should cautiously choose ETT depth..

Clinical characteristics and outcomes of the right congenital diaphragmatic hernia compared to the left: a 10-year single-center experience

PURPOSE

The features of right-sided congenital diaphragmatic hernias (RCDHs) are quite different from those of left-sided CDHs (LCDHs). We have summarized the features of RCDHs experienced in our institution.

METHODS

This retrospective study analyzed the cases of patients with CDH registered at our institution between 2011 and 2020. Defects on each side were compared based on prenatal diagnosis, medical treatment, type of surgery, and outcomes.

RESULTS

A total of 101 patients underwent surgery at our institution during the neonatal period, and 11 had RCDHs. RCDHs and LCDHs were significantly different in terms of extracorporeal membrane oxygenation (36% vs. 6%, p = 0.002), patch repair (81% vs. 28%, p < 0.001), recurrence rate (36% vs. 11%, p = 0.022), and length of hospital stay (117 days vs. 51 days, p = 0.012). The severity of the fetal diagnosis did not reflect postnatal severity. All patients with RCDH survived to discharge, and there was no significant difference in survival rate between the right and left sides.

CONCLUSION

Neonates with RCDH required more intensive treatments; however, the survival rate was comparable between RCDH and LCDH. RCDH was significantly different from LCDH and an optimal treatment strategy for RCDHs should be established.

Pneumothorax Causing Pneumoperitoneum: Role of Surgical Intervention

The most common cause of a pneumoperitoneum is a perforation of a hollow viscus and the treatment is an exploratory laparotomy; nevertheless, not all pneumoperitoneums are due to a perforation and not all of them need surgical intervention. We hereby present a case of pneumoperitoneum due to a diaphragmatic defect, which allowed air from a pneumothorax to escape through the diaphragmatic hernia into the abdominal cavity.

Redefining outcomes in right congenital diaphragmatic hernia

PURPOSE

Available data comparing the management and outcome of right-sided (R-CDH) vs left-sided congenital diaphragmatic hernia (L-CDH) are inconsistent. Large-volume CDH studies are limited by small numbers of R-CDH or are confounded by compilations from multiple institutions with multiple treatment strategies. Consequently, they are underpowered to draw conclusions. To define the behavior and outcomes of R-CDH better, we report the largest single-institution series of R-CDH and ask if factors traditionally linked to poor prognosis in L-CDH were applicable to R-CDH.

METHODS

We reviewed a single institution's experience with 267 consecutive evaluable neonates with unilateral CDH repaired from 1990 to 2006, with specific focus on R-CDH. chi(2) tests were performed for disease-related categorical variables. Two-tailed unpaired t tests were used for continuous variables. Factors associated with morbidity and survival were determined by univariate regression. Statistical significance was set at P < .05.

RESULTS

Forty right-sided (15%) and 227 (85%) left-sided cases of CDH were identified. Prenatal diagnosis was made in 20 right-sided vs 170 left-sided defects (50% vs 75%, P < .01). Survival was 22 of 40 in R-CDH compared with 175 of 227 in L-CDH (55% vs 77%, P < .01). Extracorporeal membrane oxygenation was required in 16 right-sided and 33 left-sided cases (40% vs 15%, P < .001). A diaphragmatic patch was used in 22 of 29 right-sided compared with 82 of 199 left-sided repairs (76% vs 41%, P < .01); rates of abdominal wall prosthesis were also higher in right-sided hernias (38% vs 19%, P < .05). No differences were detected in right-sided vs left-sided recurrences (14% vs 8%, P = .38), mean time from birth to operation (5.3 vs 4.8 days, P = .80), or presence of cardiac anomalies (15% vs 12%, P = .63). Morbidity persisting beyond 6 months of age was present in 16 of 22 R-CDH survivors compared with 76 of 175 L-CDH survivors (73% vs 43%, P > .05). Among R-CDHs, prenatal diagnosis was the only factor to predict survival by univariate regression (P < .01). Use of a prosthesis in the diaphragm (P < .05) for R-CDH repair correlated with morbidity.

CONCLUSION

Although previous reports suggest that associated anomalies, need for extracorporeal membrane oxygenation, and time to repair can influence L-CDH survival, these data do not support extrapolation to R-CDH survival. Right-sided CDH carries a disproportionately high morbidity and mortality. Prenatal diagnosis was the only factor predictive of R-CDH survival. Morbidity may correlate with use of prosthetic material for R-CDH repair. Right-sided CDH is a unique disease that may require a modified antenatal consultation.

Outcomes of congenital diaphragmatic hernia: a population-based study in Western Australia

OBJECTIVES

There have been many recent reports of improved survival rates for congenital diaphragmatic hernia (CDH), largely derived from institution-based data. These are often flawed by case selection bias. The objectives of this study were to document the true incidence, management, and outcomes of CDH in a geographically defined population over a 12-year period and to determine the changing trends in these over time. We also sought to ascertain the prenatal and postnatal factors associated with morbidity and death among these infants.

METHODS

A retrospective study of all cases of CDH in Western Australia from 1991 to 2002 was conducted. Cases were identified from 5 independent databases within the Western Australian health network, including the Western Australian Birth Defects Registry. All fetuses and neonates diagnosed with CDH in Western Australia during this period were identified, including miscarriages, stillbirths, and terminations of pregnancies in which a diagnosis of fetal CDH had been made, as well as those diagnosed postnatally. Cases not known to involve CDH until diagnosis at autopsy were also included. Infants with diaphragmatic eventration were excluded from the study. Detailed information was obtained from review of maternal and infant medical records.

RESULTS

One hundred sixteen cases of CDH were identified. Of these, 71 (61%) infants were born alive and 37 survived beyond 1 year of age (52% of live-born infants, 32% of all cases of CDH). Pregnancies involving 38 (33%) fetuses were terminated electively, 4 (3%) fetuses were aborted spontaneously, and 3 (3%) fetuses were stillborn. Another major congenital anomaly was present in 54 (47%) cases. Twenty-one (18%) cases had other anomalies that were likely to be fatal. Of all cases with an additional major anomaly, 42 (78%) died. Twenty-seven (71%) of 38 fetuses for whom the pregnancy was terminated had another major anomaly. Twenty-three (32%) live-born infants had another major anomaly (4 of which were considered fatal conditions); however, this did not affect their survival rates. Fifty-three percent of cases were diagnosed prenatally, and 49% of these pregnancies were then terminated. Of live-born infants with prenatally diagnosed CDH, 10 (33%) survived beyond 1 year of age. The gestational age at diagnosis did not affect the survival rate for live-born infants. Postnatal diagnosis occurred in 55 (47%) cases. Of these, 41 (74%) case subjects were born alive and diagnosed on clinical grounds after birth. In the remaining 14 cases, the diagnosis was made in postmortem examinations of fetuses from pregnancies that were terminated for other reasons (8 cases) or after spontaneous abortion or stillbirth (5 cases). Significant differences were found between prenatally and postnatally diagnosed live-born infants. Among live-born infants, prenatal diagnosis was associated with a significantly reduced survival rate (33%, compared with 66% for postnatally diagnosed infants). Prenatally diagnosed live-born infants were of lower birth weight and were born at an earlier gestational age. There was no statistically significant difference between the 2 groups in the onset of labor (spontaneous or induced) or in the rate of elective cesarean sections. Prenatally diagnosed live-born infants were more likely to be delivered in a tertiary perinatal center and were intubated more commonly at delivery. No difference was found in the Apgar scores at either 1 or 5 minutes between the groups. Of 71 live-born infants, 37 (52%) survived to 1 year of age. The majority of deaths occurred within the first 7 days of life (44%). Preoperative air leaks occurred for 16 (22%) infants, of whom 14 (88%) died. Factors found to predict death of live-born infants included prenatal diagnosis, right-sided hernia, major air leak, earlier gestational age at birth, lower birth weight, and lower Apgar scores at 1 and 5 minutes. Over the course of the decade, there were significant increases in the proportion of cases in which the diagnosis of CDH was made with prenatal ultrasonography and in the number of live-born infants born at the tertiary perinatal center. The mortality rate for all cases, the mortality rate for live-born infants, and the proportion of pregnancies involving prenatally diagnosed cases that were terminated electively were all greater in the later epoch but not significantly so.

CONCLUSIONS

This was a comprehensive, population-based study of CDH, with full case ascertainment, large sample size, and complete outcome data for all cases. The majority of published studies of CDH examined specific patient populations, such as neonates referred to tertiary pediatric surgical centers. Invariably, those studies failed to detect the demise of cases with CDH before arrival at the referral center, whether through termination of pregnancy, in utero fetal demise, or postnatal death occurring before transfer. Exclusion of these cases from calculations of mortality rates results in significant case selection bias. In our study, 35% of live-born infants died before referral or transport. The population of infants reaching the tertiary surgical center represented only 40% of the total cases of CDH. Wide variations in reported survival rates occur throughout the literature. These differences reflect the influence of this case selection bias, as well as variable referral policies and management practices. For our study population, survival rates differed vastly depending on the subgroup analyzed. Ninety-two percent of postoperative infants survived beyond 1 year of age, as did 80% of infants who reached the surgical referral center. However, only 52% of live-born infants, 32% of all cases, and 16% of all prenatally diagnosed cases survived. Therefore, the overall mortality rate for this condition remains high, despite increased prenatal detection, transfer to tertiary institutions for delivery, and advances in neonatal care, and is influenced significantly by the rate of prenatal termination. In our study, 33% of all cases of CDH and 49% of prenatally diagnosed fetuses underwent elective termination of pregnancy. This large number of fetal terminations confounds the accurate assessment of the true outcomes of this condition.

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.

Congenital diaphragmatic hernia: a meta-analysis of mortality factors

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Is prognostication in congenital diaphragmatic hernia possible without sophisticated investigations?

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

Congenital diaphragmatic hernia--does the side of the defect influence the incidence of associated malformations?

BACKGROUND/PURPOSE

Patients with congenital diaphragmatic hernia (CDH) frequently have associated anomalies. Experiments in the nitrofen CDH model have shown differential embryonic cell death patterns in rodents suggesting unique mechanisms in the formation of right-sided (RCDH) or left-sided (LCDH) diaphragmatic hernia. These findings provide insight into the pathogenesis of CDH and may aid our understanding on the spectrum of associated anomalies commonly observed in humans. This study therefore set out to test the hypothesis that the side of the diaphragmatic defect in humans is related to the incidence and severity of coexistent organ malformations.

METHODS

The medical and autopsy records of 301 CDH patients presenting to two institutions over a 23-year period were examined to analyze these factors.

RESULTS

One hundred patients (33%) were found to have one or more associated anomalies. The incidence of multiple-RCDH (10%) versus LCDH (7.3%) and cardiac anomalies-RCDH (10%) versus LCDH (8.5%) was similar in both groups of patients. However, the hypoplastic heart syndrome was a unique feature in 5 of 22 patients (23%) with LCDH who had cardiac abnormalities. This cardiac anomaly may be related developmentally to LCDH.

CONCLUSION

The cellular mechanisms underlying the genesis of this spectrum of abnormalities in humans and the nitrofen CDH model warrant further study to elucidate factors governing embryonic cell fate and phenotype expression.

Indication and results of thoracic surgical procedures in premature infants

This analysis concerns three groups of malformations: Congenital diaphragmatic hernia, patent ductus arteriosus, and oesophageal atresia. We registered a total mortality rate for all congenital diaphragmatic hernias and defects of 28.5%; the rate in full-term neonates was 27.6% and in premature infants 33.6%. Of 65 infants with a patent ductus arteriosus and a birth weight less than 1500 g, 14 died (21.5%). In most cases death was caused by sepsis. Among the 159 patients with oesophageal atresia who were treated in our hospital, 58 were premature infants. During the last 20 years, the total mortality rate among our patients was 28.9%. We had a mortality rate of 44.8% in premature infants and of 19.8% in full-term neonates. An analysis of the last 10 years showed a survival rate of 97% in healthy infants (group A in Waterston's classification). In group C, the most disadvantageous group (premature infants, severe anomalies), the rate was 61%.

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.

Timing of surgery for congenital diaphragmatic hernia: is emergency operation necessary?

Congenital diaphragmatic hernia (CDH) is considered by most researchers to be a surgical emergency. However, early repair does not necessarily improve respiratory function or reverse fetal circulation, and many patients deteriorate postoperatively. As a result, in 1985, we began to employ a protocol in which surgery was delayed until the PCO2 was maintained below 40 and the child was hemodynamically stable; children in whom these criteria could not be achieved died without surgical repair. Sixty-one consecutive infants with CDH were managed over 4 years; 31 from 1983 to 1984 (group 1) and 30 from 1985 to 1986 (group 2). The groups were similar with respect to sex, side of the defect, birth weight, gestational age, incidence of pneumothorax, and blood gases. High frequency oscillation was used with increasing frequency during the study period, for patients with refractory hypercarbia (13% in group 1, 30% in group 2). All patients were initially paralyzed and ventilated. Mean time from admission to surgery was 4.1 hours in group 1 and 24.4 hours in group 2 (P less than .05). In group 1, 87% of patients had surgical repair (77% within eight hours of admission, 10% after eight hours), and in group 2 only 70% of patients had surgery (10% within eight hours, 60% after eight hours). All patients who were not operated on died. Overall mortality was 58% in group 1 and 50% in group 2; this difference was not statistically significant. These data indicate that our current approach has not increased overall mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Improving survival in the treatment of congenital diaphragmatic hernia

Thirty-two infants were treated for congenital diaphragmatic hernia at our institution from 1979 to 1984. Eight were in no or minimal distress at birth and had operative intervention when they were more than 24 hours old; survival was 100%. The remaining 24 neonates required immediate intubation and ventilation followed by operation at less than 12 hours of age. Overall survival was 54%; survival was 31% (4 of 13 patients, Group 1) in the first three years of the series and 82% (9 of 11 patients, Group 2) in the last three years (p less than 0.001). Apgar score, gestational age, birth weight, and incidence of associated congenital heart disease were equal for the two groups (all, p greater than 0.05). The two groups also were examined with reference to alveolar-arterial oxygen differences P(A-a)O2 and mean airway pressure (MAP). The best preoperative P(A-a)O2 was greater than 600 mm Hg for 7 neonates in Group 1 and 6 in Group 2, and survival was 0% and 71%, respectively (p less than 0.001). Infants with a postoperative MAP of 13 cm H2O or greater had a higher mortality (100% in Group 1 and 50% in Group 2, p greater than 0.05). Our treatment protocol was studied to determine those methods related to improved survival. Sodium bicarbonate infusion was used earlier in Group 2 as a prophylaxis against persistent fetal circulation (PFC) (p greater than 0.05). The incidence of severe PFC dropped from 85 to 54% (p greater than 0.05). Higher ventilator rates rather than pressures were used to achieve equally effective ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Congenital diaphragmatic hernia: arterial structural changes and persistent pulmonary hypertension after surgical repair

Some infants with congenital diaphragmatic hernia who die after surgical correction have a transient postoperative period during which systemic oxygenation is adequate (honeymoon period), whereas others have persistent hypoxemia. Using morphometric techniques, we analyzed lung structure, especially the arterial bed, in seven infants who died within 1 week of surgical repair. Three infants comprised the honeymoon group, the PaO2 transiently being greater than 150 mm Hg in the descending aorta (FiO2 1.0); four infants comprised the no-honeymoon group and never had PaO2 greater than 85 mm Hg. All lungs were hypoplastic for age; with one exception, infants in the no-honeymoon group had smaller lungs. Arterial structure in the no-honeymoon group contributed to a greater reduction in pulmonary arterial cross-sectional area. Each infant in the no-honeymoon group had muscularization of intra-acinar arteries and failure of perinatal increase in compliance of small preacinar arteries, features not seen in the honeymoon group or in the normal newborn infant. In addition, compared with the honeymoon group, luminal area of preacinar and intra-acinar arteries in the no-honeymoon group was decreased by reduced external diameter or increased medial thickness. Clinical deterioration in the honeymoon group is based on a vasoconstrictive response of the hypoplastic vascular bed. Persistent hypoxemia in the no-honeymoon group is based on both severity of pulmonary hypoplasia and structural remodeling of the pulmonary arteries.

The pulmonary hemodynamic response to perioperative anesthesia in the treatment of high-risk infants with congenital diaphragmatic hernia

The continuing high mortality in congenital diaphragmatic hernia led us to study the cardiopulmonary disturbances associated with this lesion. Since these infants infrequently have right-to-left shunting in the operating room, we adopted a treatment protocol of: continuing general anesthesia in the postoperative period using fentanyl and pancuronium; cardiac catheterization postoperatively, including placement of a pulmonary artery line and a pulmonary angiogram; rapid frequency ventilation; moderate fluid restriction; and avoidance of vasodilators until other means of management had clearly failed. Fourteen high-risk infants, presenting within 6 hours of birth, were studied and compared to 17 high-risk infants, who served as historical controls. As revealed by the physiologic data acquired in the catheterization laboratory, high-risk infants divided into "Responder" and "Nonresponder" groups. Seven of 10 "Responders" actually shunted left to right during the catheterization, demonstrating a low pulmonary vascular resistance. Seven of 10 subsequently demonstrated significant right-to-left shunting at the level of the ductus and the foramen ovale, indicating the hyperreactivity of the pulmonary vascular bed. All but one was managed successfully by ventilatory adjustments and deepening of the level of anesthesia. "Nonresponders" had a fixed right-to-left shunt unresponsive to any medical or ventilatory manipulation. All "Nonresponders" died. Pulmonary angiography suggested a smaller diameter of the affected pulmonary artery compared to the main pulmonary artery in the "Nonresponders." This implies true hypoplasia resulting in a vasculature too small to accept a full cardiac output. Survival in the treatment group "Responders" was eight of 10 (80%) v seven of 14 (50%) in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)