Mortality among infants with high-risk congenital diaphragmatic hernia in Singapore

A single-center observational study on congenital diaphragmatic hernia: Outcome, predictors of mortality and experience from a tertiary perinatal center in Singapore

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a common birth defect associated with significant mortality and morbidity. There is limited outcome data on CDH in the Southeast Asian region. Rapid accessibility to our CDH Perinatal Center, as a consequence of the small geographic size of our country and efficient land transportation system, has largely eliminated deaths of live outborn babies prior arrival at our center. We selected a study period when extracorporeal membrane oxygenation (ECMO) support was not available at our institution. The data will therefore be relevant in developing management guidelines and antenatal counselling for perinatal centers in this region managing CDH with limited resources, without ECMO facilities.

METHODS

A retrospective study of antenatally or postnatally diagnosed CDH infants born between January 2002 and June 2005 was performed. We selected this study period as ECMO support was not available over this period. We studied the demographics, clinical characteristics, postnatal predictors of mortality and outcomes of CDH infants in a single tertiary institution.

RESULTS

A total of 24 patients with CDH were identified. Seventy-nine percent of liveborns with CDH survived to hospital discharge. Antenatal detection rate was 83.3%. Significant postnatal predictors of mortality were preoperative pneumothorax (p = 0.035), high CRIB score (p = 0.007), low one- and five-minute Apgar score (p = 0.011, p = 0.026 respectively) and high pCO2 on initial arterial blood gas (p = 0.007). At one-year follow-up, three patients had delayed gross motor milestones which resolved subsequently. Re-admissions were required for recurrent bronchiolitis (33%) and oesophageal reflux which resolved in all cases. Two (13.3%) infants had surgical complications and needed re-admission for probable adhesive intestinal obstruction; one required adhesiolysis and the other was managed conservatively with good outcome.

CONCLUSION

A single-center CDH outcome in Singapore, without ECMO use, was good. This is a cohort now with long-term survival outcome which will be valuable to the neonatology community.

A Clinical Study on Congenital Diaphragmatic Hernia in Neonates: Our Institutional Experience

Background:

Congenital diaphragmatic hernia (CDH) is a complex developmental defect having a multifactorial etiology; i majority of cases (~80%), the cause is not known. Survival rates for patients with CDH have increased over the past decade with early prenatal detection and better postnatal management including surgery. Clinical profile and the outcome of 83 CDH neonates were studied and analyzed over a period of 12 years in our institute.

Aims and Objectives:

The clinical study was to analyze the clinical profile and outcome of CDH among the neonates in a tertiary care referral neonatal and pediatric center in Karnataka, India.

Materials and Methods:

This was a retrospective and prospective observational study conducted from January 2005 to March 2017, over a period of 12 years in a tertiary care referral neonatal and pediatric center in southern India. Clinical characteristics and risk factors of 83 neonates admitted and diagnosed with CDH were compared between survivors and nonsurvivors both preoperatively and postoperatively. Neonates with clinical and intraoperative diagnosis of diaphragmatic eventration were not included in this study. Multivariate logistic regression analysis was performed to determine independent predictors for mortality.

Results:

A total of 83 neonates admitted and diagnosed with CDH were included in this study; 73 of them underwent surgical repair. The total survival rate in neonates with CDH was 70/83 (84.33%) and the overall operative mortality was 3/73 (4.1%). There was a significant difference between CDH neonates who survived 70/83 (84.33%) and those who died 13/83 (15.67%), in the age on admission, 5 min Apgar score, onset of respiratory distress, preoperative ventilation, the presence of persistent pulmonary hypertension of the newborn (PPHN), high-frequency oscillatory ventilation (HFOV), and length of hospital stay with P < 0.05. Using multivariate logistic regression analysis, the following factors independently predicted mortality: onset of respiratory distress in hours (odds ratio: 0.5, 95% confidence interval: 0.37–0.82) and preoperative ventilation (odds ratio: 0.02; 95% confidence interval: 0.0028–0.1558). When we compared CDH neonates who survived after surgery (n = 70) with those who expired (n = 3) postoperatively, there was a significant difference in the gestational age in weeks, side of CDH, PPHN, HFOV and length of hospital stay with P < 0.05.

Conclusion:

CDHs are common on the left side with fairly good prognosis. Though, the right-sided CDH are rare; they do carry a good prognosis, as it was seen in our experience.

Epidemiology and outcome of congenital diaphragmatic hernia: a 9-year experience

The aim of this study was to report the birth prevalence and short-term outcome of congenital diaphragmatic hernia (CDH) in a large geographically defined population, and to assess the feasibility of performing a randomised control trial (RCT) in this population. Data were collected on all cases of CDH reported to the East Midlands and South Yorkshire Congenital Anomalies Register between 1997 and 2005. A total of 194 cases of CDH were identified from 547,025 births; a birth prevalence of 3.5/10,000. Overall 1-year survival was 42%. In total, 69% of cases resulted in a live birth, of these 61% survived to 1 year; 73% were diagnosed antenatally and 22% postnatally, with 1-year survivals 30% and 71%, respectively. A total of 54% were isolated cases and 46% associated with another anomaly, with more live births (80% vs. 56%) and better 1-year survival (62% vs. 19%) with isolated CDH. Overall, only 83 babies were born alive with an isolated CDH: the only group suitable for inclusion in a RCT. In conclusion, given the small numbers of live isolated CDH cases it is impossible that any network alone would be able to perform a valid RCT of treatments, highlighting the need for collaborative international trials to address this complex condition.

Birth weight and McGoon Index predict mortality in newborn infants with congenital diaphragmatic hernia

BACKGROUND

Despite improvements in clinical management, mortality of congenital diaphragmatic hernia (CDH) remains high. Early prediction of mortality risk helps in comparing strategies and/or performances of different centers. Birth weight (BW), Apgar Score at 5 minutes, and modified McGoon Index (MGI) calculated by the ratio between the diameters of pulmonary arteries and the descending aorta have been used to determine mortality of CDH.

AIM

The purpose of this study is to evaluate the relationship between early detectable variables and survival in newborns with CDH intubated at birth, managed with "gentle" ventilation and delayed surgery.

METHODS

All medical records of patients affected by high-risk CDH and treated with a standardized protocol at Bambino Gesù Children's Hospital, Rome, Italy, between January 2002 and September 2004 were reviewed. Prenatal diagnosis, gestational age, BW, sex, side of hernia, and MGI were recorded on admission. The relationship with mortality of each variable was evaluated by univariate analysis. Subsequently, a predictive model of mortality was developed using a logistic regression: the explanatory variables, BW, and MGI were dichotomized in high (HBW and HMGI) and low (LBW and LMGI) according to the best cutoff found with receiver-operating characteristic curves.

RESULTS

Thirty-four newborns with CDH, treated with a standardized protocol, were studied. The main characteristics of the 34 patients were BW, 2886 g (1500-3620 g); gestational age, 37.7 weeks (32-42 weeks); male/female, 22/12; right/left, 8/26; prenatal diagnosis, 29; MGI, 1.31 (0.9-1.85). Only BW and MGI were significantly (P < .05) associated with mortality at the univariate analysis. The best cutoff values were 2755 g for BW (sensitivity, 70%; specificity, 74%) and 1.25 for MGI (sensitivity, 73%; specificity, 78%). Using these limits, BW and MGI resulted independently associated with mortality in the multivariate analysis. Using the 4 possible combinations, the LBW associated with the LMGI presented the highest prediction of mortality (80%).

CONCLUSIONS

Birth weight and MGI, variously combined, were predictive of mortality. Because they are not influenced by subsequent modalities of care, they can be considered as valid early severity scores in CDH and used for comparing strategies and/or performances of different centers.

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.

Outcome of congenital diaphragmatic hernia

The outcome of congenital diaphragmatic hernia (CDH) differs for different stages of the fetus or infant's life (i.e., antenatal, immediate postnatal, and postoperative). Assessing combined data from nonrandomized studies is technically difficult. Following recognized methods of reviewing such trials, we aimed to review the available literature on the outcome of CDH to provide a guide to clinicians when counselling parents who have a fetus/infant with this condition. Thirty-five studies reporting data for CDH from 1985 to March 1998 were identified using a high sensitive search strategy, hand-searching journals, and reviewing references of relevant studies. These were systematically reviewed. The median overall mortality was 58% (interquartile range (IQR), 43-65%) for babies diagnosed in utero, 48% (IQR, 35-55%) if born alive, and 33% (IQR, 18-54%) postoperatively. Diagnosis before 25 weeks of gestation is not a uniformly bad prognostic indicator (median mortality, 60%). Outcome was worse for those fetuses with other anomalies (median mortality, 93%). The median percentage mortality for all infants born alive and treated in extracorporeal membrane oxygenation (ECMO) centers was 34% (IQR, 26-47%). Median percentage mortality for all ECMO-treated infants was 44% (IQR, 35-50%). Different treatment strategies may have a variable impact on outcome. These figures, together with local data, may help in parental counselling on prognosis for fetuses/infants with CDH.

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.

The role of futility judgments in improperly limiting the scope of clinical research

In medical research, the gathering and presenting of data can be limited in accordance with the futility judgments of the researchers. In that case, research results falling below the threshold of what the researchers deem beneficial would not to be reported in detail. As a result, the reported information would tend to be useful only to those who share the valuational assumptions of the researchers. Should this practice become entrenched, it would reduce public confidence in the medical establishment, aggravate factionalism within the research community, and unduly influence treatment decisions. I suggest alternative frameworks for measuring survival outcomes.