Prediction of outcome in congenital diaphragmatic hernia

Predicting lethal pulmonary hypoplasia in congenital diaphragmatic hernia (CDH): Institutional experience combined with CDH registry outcomes

BACKGROUND

The Severe Pulmonary Hypoplasia and Evaluation for Resuscitative Efforts (SPHERE) protocol was developed to attempt to identify CDH patients with likely lethal pulmonary hypoplasia. We present our experience with this protocol and utilize the CDH Registry to critically assess the protocol.

METHODS

SPHERE patients identified based on prenatal imaging (10/2009-1/2018) were offered ECMO if meeting postnatal physiologic criteria, while others received comfort measures. Within the CDH Registry, patients with suspected severe CDH were identified and separated into "passed" (lowest pCO2 ≤100) versus "failed" (lowest pCO2 >100) groups.

RESULTS

Of 23 SPHERE patients, 57% (13/23) passed criteria for ECMO and survival was 46% (6/13) in that cohort. Of 4912 patients in the CDH Registry, 265 met criteria. There was no difference in survival rates between those that "passed" (122/227; 54%) versus "failed" (18/38; 47%). However, the latter had longer ECMO runs and more required ventilator/ECMO support at 30 days. Amongst survivors, the "failed" group had longer hospital stays and more frequently required tube feeds at discharge.

CONCLUSIONS

The SPHERE protocol did not predict mortality in the CDH Registry. However, our data suggest resource utilization is significant when unable to reach pCO2 ≤100 despite resuscitation. Morbidity remains high in this group.

LEVEL OF EVIDENCE

Level III ANNOTATION OF CHANGES: Institutional Review Board Approval at University of Michigan (HUM00031524 and HUM00044010) TYPE OF STUDY: Retrospective Review.

Comparison of early postnatal prediction models for survival in congenital diaphragmatic hernia

OBJECTIVE

To compare the PF-PCO₂ equation-partial pressure of arterial oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) minus partial pressure of carbon dioxide (PCO₂)-to three other tools for postnatal prediction of survival in infants with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

A retrospective analysis of 203 infants with CDH from 1 January 2003 to 30 June 2018. Area under the curve (AUC) analysis was performed for survival and secondary outcomes of survival without extracorporeal membrane oxygenation support (ECMO) and death despite ECMO. Predictive scores were calculated to determine cutoff for PF-PCO₂ score.

RESULTS

The PF-PCO₂ tool had the highest AUC (0.84 for survival, 0.92 for survival without ECMO, and 0.83 for death despite ECMO). PF-PCO₂ best predicted survival when >-60 and survival without ECMO when >+80. There was no optimal cutoff score for death despite ECMO.

CONCLUSION

The PF-PCO₂ tool best predicted postnatal survival in infants with CDH.

Predicting outcomes in congenital diaphragmatic hernia

Identification of CDH infant populations at high risk for mortality postnatally may help to develop targeted care strategies, guide discussions surrounding palliation and contribute to standardizing reporting and benchmarking, so that care strategies at different centers can be compared. Clinical prediction rules are evidence-based tools that combine multiple predictors to estimate the probability that a particular outcome in an individual patient will occur. In CDH, a suitable clinical prediction rule can stratify high- and low-risk populations and provide the ability to tailor management strategies based on severity. The ideal prediction tool for infants born with CDH would be validated in a large population, generalizable, easily applied in a clinical setting and would clearly discriminate patients at the highest and lowest risk of death. To date, 4 postnatal major clinical prediction rules have been published and validated in the North American CDH population. These models contain variables such as birth weight, Apgar score, blood gases, as well as measures of pulmonary hypertension, and associated anomalies. In an era of standardized care plans and population-based strategies, the appropriate selection and application of a generalizable tool to provide an opportunity for benchmarking, policy creation, and centralizing the care of high-risk populations. A well-designed clinical prediction tool remains the most practical and expedient way to achieve these goals.

Persistent hypercarbia after resuscitation is associated with increased mortality in congenital diaphragmatic hernia patients

BACKGROUND

Within congenital diaphragmatic hernia (CDH) care, there have been attempts to identify clinical parameters associated with patient survival, including markers of postnatal pulmonary gas exchange. This study aimed to identify whether postnatal pulmonary gas exchange parameters correlated with CDH patient survival.

METHODS

A retrospective review was performed of isolated CDH neonates treated at a single institution from 1/2007 to 12/2013. Patient demographics, prenatal imaging, and postnatal clinical parameters, including arterial blood gas values within the first 24hours of life, were collected.

RESULTS

Seventy-four patients with isolated CDH were identified. Fifty-seven had fetal MRI. Overall, 30-day patient survival was 85%. Sixteen infants (22%) required ECMO within 24hours. Mean initial PaCO2 in nonsurvivors was higher, and infants who remained hypercarbic postresuscitation (72±19mmHg) had a worse prognosis than those who resuscitated to a normal PaCO2 (39±1.6mmHg) (p<0.001). Prenatal fetal lung volumes measured by MRI were not strongly correlated with PaCO2 levels.

CONCLUSION

CDH nonsurvivors are unable to maintain sufficient pulmonary gas exchange during the first 24hours of resuscitation. Furthermore, prenatal fetal lung volumes are weakly correlated with actual pulmonary gas exchange. These data may be useful for patient counseling during the resuscitative phase of CDH care.

A clinical prediction rule for the severity of congenital diaphragmatic hernias in newborns

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a condition with a highly variable outcome. Some infants have a relatively mild disease process, whereas others have significant pulmonary hypoplasia and hypertension. Identifying high-risk infants postnatally may allow for targeted therapy.

METHODS

Data were obtained on 2202 infants from the Congenital Diaphragmatic Hernia Study Group database from January 2007 to October 2011. Using binary baseline predictors generated from birth weight, 5-minute Apgar score, congenital heart anomalies, and chromosome anomalies, as well as echocardiographic evidence of pulmonary hypertension, a clinical prediction rule was developed on a randomly selected subset of the data by using a backward selection algorithm. An integer-based clinical prediction rule was created. The performance of the model was validated by using the remaining data in terms of calibration and discrimination.

RESULTS

The final model included the following predictors: very low birth weight, absent or low 5-minute Apgar score, presence of chromosomal or major cardiac anomaly, and suprasystemic pulmonary hypertension. This model discriminated between a population at high risk of death (∼50%) intermediate risk (∼20%), or low risk (<10%). The model performed well, with a C statistic of 0.806 in the derivation set and 0.769 in the validation set and good calibration (Hosmer-Lemeshow test, P = .2).

CONCLUSIONS

A simple, generalizable scoring system was developed for CDH that can be calculated rapidly at the bedside. Using this model, intermediate- and high-risk infants could be selected for transfer to high-volume centers while infants at highest risk could be considered for advanced medical therapies.

A simplified formula using early blood gas analysis can predict survival outcomes and the requirements for extracorporeal membrane oxygenation in congenital diaphragmatic hernia

The aims of this study were to investigate whether early arterial blood gas analysis (ABGA) could define the severity of disease in infants with congenital diaphragmatic hernia (CDH). We conducted a retrospective study over a 21-yr period of infants diagnosed with CDH. Outcomes were defined as death before discharge, and extracorporeal membrane oxygenation requirements (ECMO) or death. A total 114 infants were included in this study. We investigated whether simplified prediction formula [PO2-PCO2] values at 0, 4, 8, and 12 hr after birth were associated with mortality, and ECMO or death. The area under curve (AUC) of receiver operating characteristic curve was used to determine the optimum ABGA values for predicting outcomes. The value of [PO2-PCO2] at birth was the best predictor of mortality (AUC 0.803, P < 0.001) and at 4 hr after birth was the most reliable predictor of ECMO or death (AUC 0.777, P < 0.001). The value of [PO2-PCO2] from ABGA early period after birth can reliably predict outcomes in infants with CDH.

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.

Predictors of outcome in patients with congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation

BACKGROUND

The role of extracorporeal membrane oxygenation (ECMO) in patients with congenital diaphragmatic hernia is still evolving. The use of ECMO is invasive with potential complications during instrumentation for cannulation and heparinization. There are no reliable predictors of outcome in patients requiring ECMO. We aimed to identify (a) the factors that could predict outcome and (b) the incidence and relation of complications during ECMO to outcome.

METHODS

"Pre" ECMO (age, sex, birth weight, blood gasses, and ventilator settings) and "on" ECMO variables (mode of ECMO, use of nitric oxide, surfactant, liquid ventilation, inotropes, timing of repair, and complications on ECMO) were analyzed to identify predictors of outcome.

RESULTS

Fifty-two patients were included. The overall survival was 58%. Mean duration of ECMO (181 +/- 120 vs 317 +/- 156 hours, P = .001), use of nitric oxide (6 vs 10, P = .049), and renal complications (4 vs 14; P < .001) differed between survivors and nonsurvivors. The survival of patients requiring ECMO support for more than 2 weeks is significantly lower than that of patients requiring ECMO support for less than 2 weeks (18% vs 68%, P = .005). Multiple logistic regression revealed ECMO duration of 2 weeks or more and renal complications to be associated with mortality.

CONCLUSION

No pre-ECMO variable could be identified as predictor of mortality. Prolonged duration of ECMO and renal complications on ECMO were independently associated with mortality.

Congenital diaphragmatic hernia: a simplified postnatal predictor of outcome

BACKGROUND/PURPOSE

The incidence of congenital diaphragmatic hernia (CDH) approximates 1 in 3000 births, with mortality rates up to 50%. The ability to accurately and easily predict the outcomes of these infants could be a valuable management tool. The purpose of this study was to develop and validate a simplified clinical method for predicting survival outcomes in infants born with CDH.

METHODS

The Wilford Hall/Santa Rosa clinical prediction formula (WHSR(PF) = highest PaO2 - highest PCO2) was generated from arterial blood gas values obtained during the initial 24 hours of life, but before surgical repair or extracorporeal membrane oxygenation, in a local group of infants with CDH identified by prospective and retrospective review. The WHSR(PF) was validated using a comparative group from the Congenital Diaphragmatic Hernia Study Group (CHDSG). Bivariate, multivariable, and area under the receiver operating curve (AUC) analysis was performed using SigmaStat and SPSS statistical programs (SPSS, Chicago, Ill).

RESULTS

As initially developed from the local data, the WHSR(PF) had a positive predictive value (PPV) of 82%, a negative predictive value of 88% and AUC of 0.87. When validated against the CDHSG data, the positive predictive value was 83%, negative predictive value was 66%, and AUC 0.79. Area under the receiver operating curve analysis by the previously published CDHSG predictive equation was 0.76.

CONCLUSION

This novel formula is an easy to apply clinical tool with similar or better predictive abilities compared to previous methods of predicting survival in infants born with CDH. Currently, no method appears to have sufficient clinical accuracy for predicting the outcome of an individual infant with CDH. Further studies are indicated.

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.