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

Best pre-ductal PaO2 prior to extracorporeal membrane oxygenation as predictor of mortality in patients with congenital diaphragmatic hernia: a retrospective analysis of a Japanese database

PURPOSE

Predicting lethal pulmonary hypoplasia in infants with congenital diaphragmatic hernia (CDH) before extracorporeal membrane oxygenation (ECMO) initiation is difficult. This study aimed to predict lethal pulmonary hypoplasia in patients with CDH prior to ECMO.

METHODS

This was a multicenter cohort study involving neonates prenatally diagnosed with isolated unilateral CDH (born 2006-2020). Patients who required ECMO due to respiratory insufficiency were included in this study. Patients who underwent ECMO due to transient disorders were excluded from analysis. Blood gas analysis data within 24 h of birth were compared between survivors and non-survivors. Predictive abilities were assessed for factors with significant differences.

RESULTS

Overall, 34 patients were included (18 survivors and 16 non-survivors). The best pre-ductal PaO₂ was significantly lower in non-survivors than in survivors (50.4 [IQR 30.3-64.5] vs. 67.5 [IQR 52.4-103.2] mmHg, respectively; p = 0.047). A cutoff PaO₂ of 42.9 mmHg had a sensitivity, specificity, and positive predictive value of 50.0%, 94.4%, and 88.9%, respectively, to predict mortality.

CONCLUSION

The best PaO₂ within 24 h after birth predicted mortality following ECMO initiation. This should be shared to families and caregivers to optimize the best interests of the infants with CDH.

Clinical guidelines for the treatment of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a birth defect of the diaphragm in which abdominal organs herniate through the defect into the thoracic cavity. The main pathophysiology is respiratory distress and persistent pulmonary hypertension because of pulmonary hypoplasia caused by compression of the elevated organs. Recent progress in prenatal diagnosis and postnatal care has led to an increase in the survival rate of patients with CDH. However, some survivors experience mid- and long-term disabilities and complications requiring treatment and follow-up. In recent years, the establishment of clinical practice guidelines has been promoted in various medical fields to offer optimal medical care, with the goal of improvement of the disease' outcomes, thereby reducing medical costs, etc. Thus, to provide adequate medical care through standardization of treatment and elimination of disparities in clinical management, and to improve the survival rate and mid- and long-term prognosis of patients with CDH, we present here the clinical practice guidelines for postnatal management of CDH. These are based on the principles of evidence-based medicine using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The recommendations are based on evidence and were determined after considering the balance among benefits and harm, patient and society preferences, and medical resources available for postnatal CDH treatment.

The role of ECMO in the management of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is the most common indication for extra-corporeal membrane oxygenation (ECMO) for neonatal respiratory failure. CDH management is evolving with advanced prenatal diagnostic imaging modalities. The risk profiles of infants receiving ECMO for CDH are shifting towards higher risk. Many clinicians are developing and following clinical practice guidelines to standardize and optimize the care of CDH neonates. Despite these efforts, there are significant differences in the practice patterns among ECMO centers as to how and when they choose to initiate ECMO for CDH, when they believe repair is safe, as well as many other nuances that are based on center experience or style. The purpose of this report is to summarize our current understanding of the new and recent developments regarding management of infants with CDH managed with ECMO.

Predictive value of oxygenation index for outcomes in left-sided congenital diaphragmatic hernia

BACKGROUND & OBJECTIVES

Congenital Diaphragmatic Hernia (CDH) is associated with significant morbidity and mortality. This study compares the efficacy of the highest oxygenation index in the first 48 h (HiOI) versus current prenatal indices to predict survival and morbidity.

METHODS

Medical records of 50 prenatally diagnosed, isolated, left-sided CDH patients treated from January 2011 to April 2016 were reviewed. Data abstracted included HiOI, lung to head ratio (LHR), observed to expected total fetal lung volume (O/E TFLV), percent liver herniation (%LH), 6 month survival, respiratory support at discharge, ventilator days and length of stay. Data were analyzed using parametric and nonparametric tests and regression analyses as appropriate.

RESULTS

HiOI was associated with significantly increased LOS (p<0.001), respiratory support at discharge (p<0.001), greater ventilator days (p=0.001) and higher odds of death (p=0.004) with risk of death increasing by 5% for every one-unit increase in OI. HiOI was statistically a better predictor of LOS than O/E TFLV (p=0.007) and %LH (p=0.02).

CONCLUSIONS

In isolated, left-sided CDH patients, HiOI is associated with higher mortality, greater length of stay, more ventilator days and increased respiratory support at discharge. HiOI is a better predictor of length of stay than O/E TFLV and %LH.

TYPE OF STUDY

Retrospective Study LEVEL OF EVIDENCE: II.

A novel multimodal computational system using near-infrared spectroscopy predicts the need for ECMO initiation in neonates with congenital diaphragmatic hernia

BACKGROUND/PURPOSE

The purpose of this study was to develop a computational algorithm that would predict the need for ECMO in neonates with congenital diaphragmatic hernia (CDH).

METHODS

CDH patients from August 2010 to 2016 were enrolled in a study to continuously measure cerebral tissue oxygen saturation (cStO2) of left and right cerebral hemispheres. NIRS devices utilized were FORE-SIGHT, CASMED and INVOS 5100, Somanetics. Using MATLAB©, a data randomization function was used to deidentify and blindly group patient's data files as follows: 12 for the computational model development phase (6 ECMO and 6 non-ECMO) and the remaining patients for the validation phase.

RESULTS

Of the 56 CDH patients enrolled, 22 (39%) required ECMO. During development of the algorithm, a difference between right and left hemispheric cerebral oxygenation via NIRS (ΔHCO) was noted in CDH patients that required ECMO. Using ROC analysis, a ΔHCO cutoff >10% was predictive of needing ECMO (AUC: 0.92; sensitivity: 85%; and specificity: 100%). The algorithm predicted need for ECMO within the first 12h of life and at least 6h prior to the clinical decision for ECMO with 88% sensitivity and 100% specificity.

CONCLUSION

This computational algorithm of cerebral NIRS predicts the need for ECMO in neonates with CDH.

LEVEL OF EVIDENCE

II.

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.

Congenital diaphragmatic hernia with(out) ECMO: impaired development at 8 years

OBJECTIVE

To evaluate developmental and social-emotional outcomes at 8 years of age for children with congenital diaphragmatic hernia (CDH), treated with or without neonatal extracorporeal membrane oxygenation (ECMO) between January 1999 and December 2003.

DESIGN

Cohort study with structural prospective follow-up.

SETTING

Level III University Hospital.

PATIENTS

35 children (ECMO: n=16; non-ECMO: n=19) were assessed at 8 years of age.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Intelligence and motor function. Concentration, behaviour, school performance, competence and health status were also analysed.

RESULTS

Mean (SD) intelligence for the ECMO group was 91.7 (19.5) versus 111.6 (20.9) for the non-ECMO group (p=0.015). Motor problems were apparent in 16% of all participants and differed significantly from the norm (p=0.015) without differences between treatment groups. For all participants, problems with concentration (68%, p<0.001) and with behavioural attention (33%, p=0.021) occurred more frequently than in reference groups, with no difference between treatment groups. School performance and competence were not affected.

CONCLUSIONS

Children with CDH-whether or not treated with neonatal ECMO-are at risk for long-term morbidity especially in the areas of motor function and concentration. Despite their impairment, children with CDH have a well-developed feeling of self-competence.

Stability prior to surgery in Congenital Diaphragmatic Hernia: is it necessary?

BACKGROUND

Delaying surgery for infants with CDH until they achieve clinical stability is common practice. Stability, however, is inconsistently defined, and many infants fail to reach pre-established criteria. We sought to determine if infants undergoing surgery without meeting pre-established criteria could achieve meaningful survival.

METHODS

All infants in the CAPSNet database were analyzed (2005-2010). Patients undergoing operative repair were divided into two groups based on whether they met strict (FiO2<0.40, conventional ventilation, preductal saturation >92%, no inotropes or vasodilators), or lenient (FiO2 <0.60, conventional ventilation, preductal saturation >88%, no vasodilators) criteria. Univariate analyses were performed comparing characteristics of those who survived after surgery (N=273) with those who did not (N=21).

RESULTS

294 patients (85%) survived to surgery. Predictors of post-operative survival included prenatal liver position (p=0.003), preoperative oxygen requirements (p=0.008), preoperative inotropes (p<0.0001), and non-conventional ventilation (p=0.004). Infants meeting strict criteria had increased survival (99%; p<0.0001). Infants meeting lenient criteria constituted 70% of survivors. Nearly one-third of survivors met neither strict nor lenient criteria.

CONCLUSIONS

Infants with CDH can achieve good survival even when criteria for pre-operative stability are not met. We suggest that all infants should be repaired even if lenient criteria for ventilatory, inotrope, or vasodilator requirements are not achieved.

Myocardial oxidative metabolism and protein synthesis during mechanical circulatory support by extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) provides essential mechanical circulatory support necessary for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur, which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative metabolism and protein synthesis. We focused on the amino acid leucine and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart 1) the fractional contribution of leucine (FcLeucine) and pyruvate to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and 2) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets (n = 22) were divided into four groups based on loading status (8 h of normal circulation or ECMO) and intracoronary infusion [(13)C(6),(15)N]-L-leucine (3.7 mM) alone or with [2-(13)C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (∼40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining 1) metabolic flexibility indicated by ability to respond to pyruvate and 2) a normal or increased capacity for global protein synthesis.

Costs of congenital diaphragmatic hernia repair in the United States-extracorporeal membrane oxygenation foots the bill

BACKGROUND

Congenital diaphragmatic hernia (CDH) is the costliest noncardiac congenital defect. Extracorporeal membrane oxygenation (ECMO) is a treatment strategy offered to those babies with CDH who would not otherwise survive on conventional therapy. The primary objective of our study was to identify the leading source of expenditures in CDH care.

METHODS

All patients surviving CDH repair were identified in the Kids' Inpatient Database (KID) from 1997 to 2006, with costs converted to 2006 US dollars. Patients were categorized into groups based on severity of disease for comparison including CDH repair only, prolonged ventilator dependence, and ECMO use. Factors associated with greater expenditures in CDH management were analyzed using a regression model.

RESULTS

Eight hundred thirty-nine patients from 213 hospitals were studied. Extracorporeal membrane oxygenation use decreased from 18.2% in 1997 to 11.4% in 2006 (P = .002). Congenital diaphragmatic hernia survivors managed with ECMO cost more than 2.4 times as much as CDH survivors requiring only prolonged ventilation postrepair and 3.5 times as much as those with CDH repair only (both P < .001). Age, multiplicity of diagnoses, patient transfer, inhaled nitric oxide use, prolonged ventilation, and ECMO use were all associated with higher costs. Extracorporeal membrane oxygenation use was the single most important factor associated with higher costs, increasing expenditures 2.4-fold (95% confidence interval, 2.1-2.8). Though the CDH repair with ECMO group constituted 12.2% of patients, this group has the highest median costs ($156,499.90/patient) and constitutes 28.5% of national costs based on CDH survivors in the KID. Annual national cost for CDH survivors is $158 million based on the KID, and projected burden for all CDH patients exceeds $250 million/year.

CONCLUSIONS

Extracorporeal membrane oxygenation use is the largest contributing factor to the economic burden in CDH. With limited health care resources, judicious resource utilization in CDH care merits further study.

Predictors of survival in congenital diaphragmatic hernia patients requiring extracorporeal membrane oxygenation: CNMC 15-year experience

OBJECTIVE

To review outcomes of patients with congenital diaphragmatic hernia (CDH) requiring extracorporeal membrane oxygenation (ECMO) at a level IIIC neonatal intensive care unit and to determine if pre-ECMO respiratory status can help predict mortality.

STUDY DESIGN

A single-center retrospective chart review was conducted on all infants with CDH treated with ECMO in the past 15 years. Demographic and clinical information, including pre-ECMO ventilatory and blood gas data, was collected. Differences between survivors and non-survivors were evaluated using independent samples t-/Mann-Whitney U-and Fisher's exact/chi (2)-tests for continuous and categorical data, respectively. Cox regression analysis was performed to evaluate predictors of survival while controlling for covariates. Significant predictors were further explored with receiver operating characteristic (ROC) curve and Kaplan-Meier survival analysis.

RESULT

Overall survival of the population of 62 patients treated with ECMO was 50%. Survivor and non-survivors were similar in birth weight, gestational age, gender, race and Apgar scores. Approximately 80% of patients in both groups had a left-sided defect. Less than half of patients were prenatally diagnosed in either group. Patients in the non-survivor group had associated anomalies (42 vs 23% for survivors) but this was not statistically significant (P=0.303). Non-survivors were more likely to be put on ECMO earlier, stay on ECMO longer and be operated upon later. On pre-ECMO blood gas analyses, survivors had higher pH and PaO(2), and lower oxygenation index and PaCO(2) compared with non-survivors. After controlling for covariates, a lower minimum PaCO(2) and side of defect were the only independent predictors of survival. ROC curve for minimum pre-ECMO PaCO(2) had a significant area under the curve (0.72, P=0.003). Survival was 27% in babies unable to achieve a pre-ECMO PaCO(2) <60 mm Hg whereas no patients survived if their lowest pre-ECMO PaCO(2) was >70 mm Hg.

CONCLUSION

Minimum achievable pre-ECMO PaCO(2) is an independent predictor of survival in patients with CDH requiring ECMO life support. These data provide useful prognostic information for counseling families and may facilitate direction of care in extreme cases where the degree of pulmonary hypoplasia may be incompatible with life.

Identifying neonates at a very high risk for mortality among children with congenital diaphragmatic hernia managed with extracorporeal membrane oxygenation

PURPOSE

The purpose of this study was to identify mortality risk factors in children with congenital diaphragmatic hernia (CDH) treated with extracorporeal membrane oxygenation (ECMO) and generate a prediction score for those at a very high risk for mortality.

METHODS

Data on first ECMO runs of all neonates with CDH, between January 1997 and June 2007, were obtained from the Extracorporeal Life Support Organization registry (N = 2678). The data were split into "training data (TD)" (n = 2006) and "validation data" (n = 672). The primary outcome analyzed was in-hospital mortality. Modified Poisson regression was used for analyses.

RESULTS

Overall in-hospital mortality among 2678 neonates (males, 57%; median age at ECMO, 1 day) was 52%. The univariate and multivariable analyses were performed using TD. An empirically weighted mortality prediction score was generated with possible scores ranging from 0 to 35 points. Of 69 who scored 14 or higher in the TD, 62 died (positive predictive value [PPV], 90%), of 37 with 15 or higher, 35 died (PPV, 95%), of 23 with 16 or higher, 22 died (PPV, 96%). A cut-off point of 15 was chosen and was tested using the separate validation dataset. In validation data, the cut-off point 15 had a PPV of 96% (23 died of 24).

CONCLUSION

Scoring 15 or higher on the prediction score identifies neonates with CDH at a very high risk for mortality among those managed with ECMO and could be used in surgical decision making and counseling.

The long-term follow-up of patients with a congenital diaphragmatic hernia: a broad spectrum of morbidity

Congenital diaphragmatic hernia (CDH) is a life-threatening anomaly with a mortality rate of approximately 40-50%, depending on case selection. It has been suggested that new therapeutic modalities such as nitric oxide (NO), high frequency oxygenation (HFO) and extracorporal membrane oxygenation (ECMO) might decrease mortality associated with pulmonary hypertension and the sequelae of artificial ventilation. When these new therapies indeed prove to be beneficial, a larger number of children with severe forms of CDH might survive, resulting in an increase of CDH-associated complications and/or consequences. In follow-up studies of infants born with CDH, many complications including pulmonary damage, cardiovascular disease, gastro-intestinal disease, failure to thrive, neurocognitive defects and musculoskeletal abnormalities have been described. Long-term pulmonary morbidity in CDH consists of obstructive and restrictive lung function impairments due to altered lung structure and prolonged ventilatory support. CDH has also been associated with persistent pulmonary vascular abnormalities, resulting in pulmonary hypertension in the neonatal period. Long-term consequences of pulmonary hypertension are unknown. Gastro-esophageal reflux disease (GERD) is also an important contributor to overall morbidity, although the underlying mechanism has not been fully understood yet. In adult CDH survivors incidence of esophagitis is high and even Barrett's esophagus may ensue. Yet, in many CDH patients a clinical history compatible with GERD seems to be lacking, which may result in missing patients with pathologic reflux disease. Prolonged unrecognized GERD may eventually result in failure to thrive. This has been found in many young CDH patients, which may also be caused by insufficient intake due to oral aversion and increased caloric requirements due to pulmonary morbidity. Neurological outcome is determined by an increased risk of perinatal and neonatal hypoxemia in the first days of life of CDH patients. In patients treated with ECMO, the incidence of neurological deficits is even higher, probably reflecting more severe hypoxemia and the risk of ECMO associated complications. Many studies have addressed the substantial impact of the health problems described above, on the overall well-being of CDH patients, but most of them concentrate on the first years after repair and only a few studies focus on the health-related quality of life in CDH patients. Considering the scattered data indicating substantial morbidity in long-term survivors of CDH, follow-up studies that systematically assess long-term sequelae are mandatory. Based on such studies a more focused approach for routine follow-up programs may be established.

Predictors and statistical models in congenital diaphragmatic hernia

Despite advances in intensive care, congenital diaphragmatic hernia (CDH) maintains a risk of death >35%. Mortality predictors have been claimed, using logistic regression. When the outcome of interest is rare (i.e. <20%), the odds ratio, measured by logistic regression, is approximately equal to the relative risk, calculated by log-binomial model. However, for common events, the odds ratio misleads the exposition risk. The aims are to identify independent predictors of mortality in high-risk CDH, using the log-binomial model and disclose if the exposition risks could differ applying in comparison the logistic regression. Details of 113 consecutive high-risk CDH neonates, baseline demographics and disease features were collected retrospectively. Log-binomial model and logistic regression were applied and compared. Overall mortality rate was 41.6% (47/113). The log-binomial model identified preoperative pneumothorax (pnx), birth weight < or = 2,500 g and liver herniation as independent mortality predictors; female gender, an advanced gestational age and a PaO(2) > or = 90 mmHg as protective factors. Using logistic regression, liver herniation and birth weight did not maintain the significance. The exposition risks for pnx, female gender and gestational age were overestimated. The odds ratio measured by logistic regression overestimated the exposition risks. Since the mortality rate is confirmed to be >20% and the exposition risks, measured by logistic regression, are misleading, the log-binomial model should be consider in CDH binary outcome studies. According to the mortality predictors identified, making every effort to plan delivery at term and lowering the risk of pnx could improve the outcome.

Secondary surfactant administration in neonates with respiratory decompensation

OBJECTIVE

To evaluate blood gases and ventilatory parameters before and after two doses of surfactant in premature infants with respiratory decompensation after recovery from primary respiratory distress syndrome (RDS).

STUDY DESIGN

This prospective pilot study enrolled infant's > or =500 g birth weight, from 7 days to 3 months of age, with a secondary respiratory decompensation lasting at least 4 h prior to study entry. Infants received two doses of surfactant, 12 h apart.

RESULT

A total of 20 neonates qualified for secondary surfactant administration. PCO2 (P<0.001); pH (P<0.001); mean airway pressure (P<0.05); FiO2 (P<0.05); modified ventilatory indices (P<0.004) and respiratory severity scores (P<0.001) improved significantly at both 12 and 24 h after surfactant administration.

CONCLUSION

Secondary surfactant administration may be effective in reducing short-term ventilatory requirements in neonates who have a respiratory decompensation after recovery from initial RDS. Randomized controlled trials are needed to confirm these preliminary findings.

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.

Efficacy of protocolized management for congenital diaphragmatic hernia. a review of 100 cases

A review of 100 consecutive cases of congenital diaphragmatic hernia (CDH) treated at our institute focusing on the efficacy of protocolized management (PM) was conducted. Of the 100 cases, 14 who became symptomatic more than 24 h after birth, and seven with fatal anomalies (four cardiac and three chromosomal) were excluded, leaving 79 subjects for this study. Of these, 41 were diagnosed prenatally (PD). Subjects were divided into four groups. Group I: No PD, no PM (n = 34), Group II: No PD, PM (n = 4), Group III: PD, no PM (n = 21), and Group IV: PD, PM (n = 20). PM includes criteria for planned delivery, use of high frequency oxygenation, nitric oxide, echocardiography (EC), and a medication schedule. Overall survival rates for Groups I, II, III, and IV were 73.5% (25/34), 75% (3/4), 38.1% (8/21), and 70.0% (14/20), respectively. Survival rates were higher when PM was used: 70.8% (Groups II, IV) versus 60.0% (Groups I, III). Survival rates were significantly lower if diagnosed prenatally (PD+): 53.7% (Groups III, IV) versus 73.7% (Groups I, II) (P < 0.01). However, in PD+ groups, survival was significantly higher if PM was used (P < 0.05). PM significantly reduced length of hospital stay (35.5 vs. 52.0 days: P < 0.05). EC was found to be a predictor for survival while post-ductal AaDO(2) was not. In 17 cases with cardiac anomalies, PM did not affect survival. Our study suggests that use of PM for prenatally diagnosed CDH cases is associated with improved outcome, although the components of PM need to be tested in prospective trials to determine their true value.

Resting and exercise cardiorespiratory function in survivors of congenital diaphragmatic hernia

Our objective was to study exercise capacity and cardiorespiratory response to exertion in survivors of congenital diaphragmatic hernia (CDH). This was a cross-sectional cohort study of 23 CDH survivors, aged 10-16 years, and 23 gender- and age-matched controls. Exercise testing was performed on a cycle ergometer, with cardiac output measurements made using exponential CO2 rebreathing. Pretest cardiorespiratory assessment was done by echocardiography and pulmonary function testing. Statistical analysis was performed using Student's t-test, regression analysis, and longitudinal model computing with spatial covariance structure. No echocardiographic evidence for pulmonary hypertension was found at rest (right ventricular systolic pressures, 27 +/- 6 mmHg). Mean pulmonary artery diameter on the side of the CDH was significantly smaller than contralaterally, but was within normal range (z-score, 0 +/- 1.1 vs. 1.2 +/- 1.6, P < 0.01). Exercise capacity was mildly reduced in CDH compared to controls and predictive data (maximum workload, 77% +/- 12% vs. 91% +/- 16% of predicted, P < 0.01). Cardiorespiratory response to exertion was not significantly different between groups. In conclusion, most adolescent CDH survivors have nearly normal exercise capacity and cardiorespiratory response to exertion. This study may prove useful in comparisons with future cohorts comprising more severely affected individuals now surviving due to improved neonatal care.

A risk-adjusted study of outcome and resource utilization for congenital diaphragmatic hernia

PURPOSE

Perinatal care of infants with congenital diaphragmatic hernia (CDH) is nonstandardized and costly. We examined a risk-adjusted cohort of patients with CDH and hypothesized that (1) among CDH survivors, the cost of the birth admission would be proportional to illness severity, and (2) this cost would be significantly higher compared with a matched non-CDH cohort.

METHODS

A retrospective review of costs and outcomes for all patients with CDH admitted to British Columbia Children's Hospital between 1999 and 2003 was performed. Risk grouping of patients with CDH using a validated admission severity score (Score for Neonatal Acute Physiology-version II [SNAP-II]) was conducted, enabling comparison among infants surviving to discharge. Hospital costs were also compared with a contemporaneous, non-CDH cohort matched for birth weight and SNAP-II.

RESULTS

Thirty-two infants with CDH were included, of who 5 required extracorporeal membrane oxygenation. Twenty-three (72%) infants survived to discharge, with an average length of stay of 46 days. Average cost per survivor to discharge was 54,102 dollars (vs 13,722 dollars for the non-CDH cohort; P < .05). After SNAP-II stratification of survivors into low-, moderate-, and high-risk groups, a significant cost difference was noted between the moderate- and low-risk and high- and low-risk groups, respectively.

CONCLUSIONS

Infants born with CDH require costly care and can be expected to consume disproportionate resources. Admission SNAP-II score correlates with total cost to discharge. Risk stratification and cost comparison of larger CDH populations may allow identification of cost-efficient treatment strategies.

The role of extracorporeal membrane oxygenation in the management of infants with congenital diaphragmatic hernia

Many infants with CDH can be managed with conventional mechanical ventilation and pharmacotherapy. However, some infants will require levels of ventilator support that are not compatible with survival. In these circumstances, extracorporeal membrane oxygenation (ECMO) has been used with varying results. The indication, type, and timing of ECMO in relation to surgery continue to evolve in an attempt to improve the outcome. At the same time, there is growing body of literature showing adverse outcomes among infants with CDH treated with ECMO, raising questions about the usefulness of ECMO in CDH. This paper reviews some of the controversies associated with the use of ECMO in CDH.

Heart rate variability as an indicator of outcome in congenital diaphragmatic hernia with and without ECMO support

OBJECTIVE

To examine differences in the spectral power content in neonates diagnosed with congenital diaphragmatic hernia (CDH) who survive or succumb.

STUDY DESIGN

A case-series study design evaluated four neonates diagnosed with CDH, two of which were supported by extracorporeal membrane oxygenation (ECMO). The electrocardiogram signal was digitized at 1000 Hz and the Lomb periodogram was computed for the series of interbeat intervals.

RESULTS

Neonates with CDH who survived had log total power values greater than 2. Those with CDH who did not survive had log total power less than 2, but generally exceeded 3 while they were supported by ECMO.

CONCLUSIONS

Neonates who consistently displayed increasing total spectral energies had a better outcome than those whose spectral energies were low. Subjects who succumbed expressed the lowest values, suggesting that a frequency-based evaluation of HRV may be a sensitive prognosticator of outcome that requires further investigation.

Risk of need for extracorporeal membrane oxygenation support in neonates with congenital diaphragmatic hernia treated with inhaled nitric oxide

BACKGROUND

Congenital diaphragmatic hernia (CDH) is often associated with severe pulmonary hypoplasia resulting in hypoxemic respiratory failure unresponsive to advanced medical management including the use of inhaled nitric oxide (iNO). For these patients, extracorporeal membrane oxygenation (ECMO) serves as the last potentially effective treatment choice. Since the efficacy of iNO in this patient population is not known and since most neonatal intensive care units using iNO for the treatment of these critically ill neonates do not provide ECMO, the ability to more accurately predict which patient is at risk for failing medical management with iNO and requires a timely transfer to an ECMO center can be life saving. Therefore, in this study, we sought to determine the risk factors for the need for ECMO in a cohort of 27 neonates with isolated left CDH and hypoxemic respiratory failure treated with iNO.

STUDY DESIGN

In this retrospective study, 27 patients with left CDH were identified during a 2-year period. During the study period, strict clinical guidelines had been used to standardize iNO therapy, to provide adequate lung inflation and cardiovascular support, and to recognize treatment failures and the need for ECMO. Logistic regression analysis was used to study the relationship between the need for ECMO and a set of suspected risk factors.

RESULTS

When subjected to logistic regression analysis, only the presence of a pneumothorax remained significantly associated with the need for ECMO (OR=22; 95% CI=2.18 to 222), while none of the other variables examined such as mean airway pressure, FiO2, PaO2, or PaCO2 were predictors for the need of ECMO after 6 hours of treatment with iNO.

CONCLUSION

These data indicate that a prompt transfer to an ECMO center should be initiated for hypoxemic patients with CDH receiving medical management with iNO if they develop an air leak syndrome.

Current therapy of infants with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a life-threatening anomaly with a significant mortality rate. Despite widespread prenatal diagnosis, few parameters have been well defined to aid in prediction of outcome of these infants. Antenatal maternal steroid administration and foetal surgery are not proven interventions. Postnatal treatment has changed over the last 10 years, with avoidance of hyperventilation and ventilator-induced lung injury resulting in improved survival. Therapies such as inhaled nitric oxide, exogenous surfactant administration and extracorporeal membrane oxygenation (ECMO) have undergone limited study, but show no clear benefit in this population. With improved outcome, principally due to avoidance of barotrauma, greater opportunity exists for long-term evaluation of survivors. To date, continuing problems with pulmonary function, nutrition and growth, effects of right ventricular hypertension and developmental issues have been identified. Through co-ordinated, multidisciplinary evaluation of CDH survivors, improved long-term outcome for these challenging patients can be attained.

The cost-effectiveness of treatment for congenital diaphragmatic hernia

BACKGROUND/PURPOSE

The cost-effectiveness of medical interventions is becoming an important issue for decision makers. Until recently, evidence of the cost-effectiveness of neonatal surgery was largely lacking. The authors analyzed the cost-effectiveness of neonatal surgery and subsequent treatment for congenital diaphragmatic hernia (CDH).

METHODS

Both costs incurred inside and outside the health care sector (eg, out-of-pocket expenses and productivity losses) were included. Quality-adjusted life years (QALYs) were measured using the EuroQol EQ-5D questionnaire. Descriptive quality-of-life data were collected using a disease-specific questionnaire. Both costs and effects basically were measured in a life-time setting.

RESULTS

Total costs of treatment average euro 42,658, mainly consisting of costs of the initial hospitalization. Productivity losses in both the patients and their caregivers appear to be minor. Treated CDH patients, even adults, suffer from respiratory difficulties and stomach aches. According to the EQ-5D, however, their quality of life does not differ from the general population, suggesting that these symptoms barely affect overall quality of life. Treatment results in a gain of 17.5 QALYs. Costs per QALY amount to euro 2,434.

CONCLUSIONS

Treatment for CDH has favorable cost-effectiveness. Considering the growing importance of cost-effective medicine, these are important and encouraging results. Health economics outlines the inevitability of making choices that directly affect patient care and places relative values on different health care programs. The results of this study provide convincing evidence that treatment for CDH is indeed cost effective.

A statistical model to predict nonsurvival in congenital diaphragmatic hernia

OBJECTIVE

To develop a predictive model using echocardiographic indices to identify nonsurvivors from survivors in preoperative patients with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

Eight cases of CDH, with a mortality rate of 38%, underwent echocardiographic study before surgical repair. Left ventricular mass (LVMASS) using the area-length method of Wyatt et al. and fractional shortening (FS) by M-mode measurements were determined.

RESULTS

We identified a nonlinear nonoverlapping distribution that predicted nonsurvivors from survivors, p=0.04. Multiple regression analysis demonstrated the quantity (LVMASS x FS)(1/2) to be correlated with nonsurvival with a coefficient of determination r(2)=0.55. Comparison of the means of the quantity (LVMASS x FS)(1/2) for the two groups suggested two distinct populations, p=0.04.

CONCLUSION

The mathematical quantity (LVMASS x FS)(1/2) calculated from echocardiographic measurements obtained preoperatively in babies with CDH may predict nonsurvival despite maximal intervention.

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.

Congenital diaphragmatic hernia

Over the last two decades there has been a constant improvement in the understanding of the pathophysiology of Congenital Diaphragmatic Hernia (CDH) and its management. However, the ideal treatment remains elusive. The earlier management strategy of immediate surgery is replaced by the principle of physiological stabilisation and delayed surgery. Conventional mechanical ventilatory techniques, with high pressures and hyperventilation to reverse ductal shunting and cause alkalinization, are being questioned because of the risks of barotrauma and consequent broncho-pulmonary dysplasia. It has also been shown that paralysis with pancuronium bromide for patients on conventional mechanical ventilation results in increased incidence of sensorineural hearing loss in childhood survivors of CDH. With the introduction of the concept of permissive hypercapnia and high frequency oscillation ventilation, the complications of pulmonary barotrauma are circumvented. Although ECMO therapy is invasive, yet has improved survival by about 15% independently, especially in critically ill infants who have the predictive mortality rate of more than 80%. Further insights into the pathophysiology of CDH and the introduction of less invasive therapeutic techniques in the form of high frequency oscillation ventilation, inhalation nitric oxide, surfactant, and perfluorocarbon liquid ventilation may even make the need for ECMO redundant.

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.

Cost-effectiveness of neonatal surgery: a review

BACKGROUND/PURPOSE

Technological developments have revolutionized both diagnosis and treatment in neonatal surgery. However, it has been increasingly recognized that financial resources might become insufficient to provide all the medical care that is technically feasible or that patients and families might desire. The purpose of this study is to apply the theory of health economics to neonatal surgery and to explore the extent and the kind of economic evaluation done in neonatal surgery.

METHODS

To explore the work done so far, the authors undertook a literature search aimed at costs and effects of surgical interventions in newborns with Ravitch' surgical index diagnoses of congenital anomalies. Common keywords in cost-effectiveness analysis were used to search Medline.

RESULTS

Evidence about the cost effectiveness of neonatal surgery is largely lacking. This is probably because of difficulties in long-term tracking of the patients and to the problem that most generic quality-of-life measures are not applicable in children yet.

CONCLUSIONS

Further cost-effectiveness research in neonatal surgery is warranted to settle priority discussions in health care when neonatal surgery is part of such discussions. Methodology for generic quality-of-life measurement in children is badly needed.

Does extracorporeal membrane oxygenation improve survival in neonates with congenital diaphragmatic hernia? The Congenital Diaphragmatic Hernia Study Group

BACKGROUND/PURPOSE

The benefit of extracorporeal membrane oxygenation (ECMO) in improving survival of neonates with congenital diaphragmatic hernia (CDH) has never been clearly demonstrated. This may be due to comparisons made between treatment groups of unequal illness severity and the low statistical power of analyses from previous studies. The authors analyzed the data from the multicenter CDH registry to determine if ECMO improves survival in CDH neonates with a high risk of mortality.

METHODS

A total of 730 neonates were enrolled in the CDH Registry from January 1995 to November 1997. Of these, 632 neonates had a complete data set and were eligible for ECMO by the weight criterion of greater than 2.0 kg. Multivariate logistic regression analysis was used to assess mortality risk for each neonate based on previously validated independent predictors of survival: birth weight and 5-minute Apgar. Five quintile groups were defined based on increasing predictive mortality risk. Multivariate logistic regression and chi2 analyses with birth weight, Apgar score at 5 minutes, and predictive mortality risk as covariates were then performed to assess survival benefit of ECMO compared with conventional therapy alone. Patient survival rate was defined as survival to discharge from hospital.

RESULTS

When analyzing all 632 neonates, ECMO neonates (n = 289) had a decidedly lower survival rate (52.9% v 77.3%, P< .001) than non-ECMO neonates (n = 343) without standardizing for the degree of illness. However, when taking into account the patients' predictive mortality risk, ECMO was associated with improved survival in the neonates with mortality risk < or = 80% (P < .05). Furthermore, ECMO was shown to be a positive independent predictor of survival when accounting for the covariates of birth weight, 5-minute Apgar, and mortality risk (P < .05).

CONCLUSIONS

ECMO significantly improves survival rates for those CDH neonates with a predictive mortality risk > or = 80%. Generally, the more critically ill the patient with CDH, the more marked the survival benefit obtained.