Multicentre, randomised controlled trial of physiological-based cord clamping versus immediate cord clamping in infants with a congenital diaphragmatic hernia (PinC): statistical analysis plan.

BACKGROUND: Infants born with congenital diaphragmatic hernia (CDH) are at high risk of respiratory insufficiency and pulmonary hypertension. Routine practice includes immediate clamping of the umbilical cord and endotracheal intubation. Experimental animal studies suggest that clamping the umbilical cord guided by physiological changes and after the lungs have been aerated, named physiological-based cord clamping (PBCC), could enhance the fetal-to-neonatal transition in CDH. We describe the statistical analysis plan for the clinical trial evaluating the effects of PBCC versus immediate cord clamping on pulmonary hypertension in infants with CDH (PinC trial). DESIGN: The PinC trial is a multicentre, randomised controlled trial in infants with isolated left-sided CDH, born ≥ 35.0 weeks of gestation. The primary outcome is the incidence of pulmonary hypertension in the first 24 h after birth. Maternal outcomes include estimated maternal blood loss. Neonatal secondary outcomes include mortality before discharge, extracorporeal membrane oxygenation therapy, and number of days of mechanical ventilation. Infants are 1:1 randomised to either PBCC or immediate cord clamping using variable random permutated block sizes (4-8), stratified by treatment centre and estimated severity of pulmonary hypoplasia (i.e. mild/moderate/severe). At least 140 infants are needed to detect a relative reduction in pulmonary hypertension by one third, with 80% power and 0.05 significance level. A chi-square test will be used to evaluate the hypothesis that PBCC decreases the occurrence of pulmonary hypertension. This plan is written and submitted without knowledge of the collected data. The trial has been ethically approved. TRIAL REGISTRATION: ClinicalTrials.gov NCT04373902 (registered April 2020).

Vascular reactivity is altered in the placentas of fetuses with congenital diaphragmatic hernia.

INTRODUCTION: Infants with congenital diaphragmatic hernia (CDH) often develop pulmonary hypertension but frequently fail to respond to vasodilator therapy, for instance because of an altered pulmonary vasoreactivity. Investigating such alterations in vivo is impossible. We hypothesised that these alterations are also present in fetoplacental vessels, since both vasculatures are exposed to the same circulating factors (e.g. endothelin-1) and respond similarly to certain stimuli (e.g. hypoxia). As proof-of-concept, we compared fetoplacental vasoreactivity between healthy and CDH-affected placentas. METHODS: Fetoplacental vascular function of healthy and antenatally diagnosed left-sided CDH fetuses was assessed by wire myography. Placental expression of enzymes and receptors involved in the altered vasoreactive pathways was measured using quantitative PCR. RESULTS: CDH arteries (n = 6) constricted more strongly to thromboxane A2 agonist U46619 (p < 0.001) and dilated less to bradykinin (p = 0.01) and nitric oxide (NO)-donor sodium nitroprusside (p = 0.04) than healthy arteries (n = 8). Vasodilation to prostacyclin analogue iloprost and adenylate cyclase stimulator forskolin, and vasoconstriction to endothelin-1 were not different between both groups. Angiotensin II did not induce vasoconstriction. Phosphodiesterase inhibitors sildenafil and milrinone did not affect responses to sodium nitroprusside, forskolin, or U46619. The mRNA expression of guanylate cyclase 1 soluble subunit alpha 1 (p = 0.003) and protein kinase cyclic guanine monophosphate (cGMP)-dependent 1 (p = 0.02) were reduced in CDH versus healthy placentas. DISCUSSION: The identified changes in the thromboxane and NO-cGMP pathways in the fetoplacental vasculature correspond with currently described alterations in the pulmonary vasculature in CDH. Therefore, fetoplacental arteries may provide an opportunity to predict pulmonary therapeutic responses in infants with CDH.

Sedation Prior to Intubation at Birth in Infants with Congenital Diaphragmatic Hernia: An International Survey on Current Practices.

INTRODUCTION: Infants with congenital diaphragmatic hernia (CDH) are commonly intubated immediately after birth. Consensus on whether to provide sedation prior to intubation in the delivery room is lacking, although avoidance of stress is especially important in this population with high risk of pulmonary hypertension. We aimed at obtaining an overview of local pharmacological interventions and at providing guidance on delivery room management. METHODS: An electronic survey was sent to international clinicians in referral centres for prenatal and postnatally diagnosed infants with CDH. This survey addressed demographic information, use of sedation and/or muscle relaxant prior to intubation, and use of pain scales in the delivery room. RESULTS: We received 93 relevant responses from 59 centres. Most centres were from Europe (n = 33, 56%), followed by North America (n = 16, 27%), Asia (n = 6, 10%), Australia (n = 2, 3%), and South America (n = 2, 3%). A total of 19% (11/59) of the centres routinely provided sedation prior to intubation in the delivery room, with midazolam and fentanyl being most often used. Methods of administration varied for all medications provided. Only 5 of 11 centres using sedation reported an adequate sedative effect prior to intubation. Muscle relaxants prior to intubation were used in 12% (7/59) of the centres, although not always in combination with sedation. CONCLUSION: This international survey shows a substantial variation in sedation practices in the delivery room and scarce use of both sedative agents and muscle relaxants prior to intubation of CDH infants. We provide guidance on developing protocols for pre-intubation medication in this population.

Survival in very preterm infants with congenital diaphragmatic hernia and association with prenatal imaging markers: A retrospective cohort study.

OBJECTIVES: To describe the outcomes of preterm born infants with congenital diaphragmatic hernia (CDH; ≤32.0 weeks of gestation) and the associations between prenatal imaging markers and survival. DESIGN: Retrospective cohort study. SETTING: Multicentre study in large referral centres. POPULATION: Infants with an isolated unilateral CDH, live born at 32.0 weeks or less of gestation, between January 2009 and January 2020. METHODS: Neonatal outcomes were evaluated for infants that were expectantly managed during pregnancy and infants that underwent fetoscopic endoluminal tracheal occlusion (FETO) therapy, separately. We evaluated the association between prenatal imaging markers and survival to discharge. Prenatal imaging markers included observed to expected lung-to-head ratio (o/e LHR), side of the defect, liver position, stomach position grade, and observed to expected total fetal lung volume (o/e TFLV). MAIN OUTCOME MEASURE: Survival to discharge. RESULTS: We included 53 infants born at 30+4 (interquartile range 29+1 -31+2 ) weeks. Survival in fetuses expectantly managed during pregnancy was 48% (13/27) in left-sided CDH and 33% (2/6) in right-sided CDH. Survival in fetuses that underwent FETO therapy was 50% (6/12) in left-sided CDH and 25% (2/8) in right-sided CDH. The o/e LHR at baseline was positively associated with survival in cases expectantly managed during pregnancy (odds ratio [OR] 1.20, 95% CI 1.07-1.42, p < 0.01), but not in cases that received FETO therapy (OR 1.01, 95% CI 0.88-1.15, p = 0.87). Stomach position grade (p = 0.03) and o/e TFLV were associated with survival (p = 0.02); liver position was not (p = 0.13). CONCLUSIONS: In infants with CDH born at or before 32 weeks of gestation, prenatal imaging markers of disease severity were associated with postnatal survival.

Termination of pregnancy after a prenatal diagnosis of congenital diaphragmatic hernia: Factors influencing the parental decision process.

OBJECTIVE: To evaluate the incidence of termination of pregnancies (TOP) and factors associated with the decision for TOP in prenatally detected congenital diaphragmatic hernia (CDH). STUDY DESIGN: Single-centre retrospective cohort includes all prenatally detected CDH cases born between January 2009 and December 2021. Parental factors, such as parity, and fetal characteristics, such as disease severity, were collected. Descriptive statistics were used to present the data. Differences between terminated and continued pregnancies were analysed. RESULTS: The study population consisted of 278 prenatally detected CDH cases of which 80% detected <24 weeks of gestation. The TOP rate was 28% in cases that were detected <24 weeks of gestation. Twenty continued pregnancies resulted in either intrauterine fetal demise (n = 6), preterm birth <24 weeks (n = 2), or comfort care after birth (n = 12). The survival rate was 70% in the remaining 195 live born cases. Factors associated with the decision for TOP were additional fetal genetic or anatomical abnormalities (p < 0.0001) and expected severity of pulmonary hypoplasia in left-sided CDH (p = 0.0456). CONCLUSION: The decision to terminate a pregnancy complicated by fetal CDH depends on the severity of pulmonary hypoplasia and the presence of additional abnormalities. This emphasises the importance of early referral to expertise centres for detailed evaluation and multidisciplinary counselling.

The Oxygen Saturation Index as Early Predictor of Outcomes in Congenital Diaphragmatic Hernia.

OBJECTIVE: The aim of the study was to evaluate the oxygen saturation index (OSI) as an early predictor of clinical deterioration in infants with congenital diaphragmatic hernia (CDH). METHODS: A single-center retrospective cohort study was conducted in consecutive infants with isolated CDH with continuous OSI measurements collected in the first 24 h after birth between June 2017 and July 2021. Outcomes of interest were pulmonary hypertension, extracorporeal membrane oxygenation (ECMO)-therapy, and mortality. We evaluated the discriminative values of the maximum OSI value and of mean OSI values with receiver operator characteristic (ROC) analysis and the area under the ROC curve. RESULTS: In 42 infants with 49,473 OSI measurements, the median OSI was 5.0 (interquartile range 3.1-10.6). Twenty-seven infants developed pulmonary hypertension on a median of day 1 (1-1), of which 15 infants had an indication for ECMO-therapy, and 6 infants died. Maximum OSI values were associated with pulmonary hypertension, ECMO-therapy, and mortality. Mean OSI values had an acceptable discriminative ability for pulmonary hypertension and an excellent discriminative ability for ECMO-therapy and mortality. Although OSI measurements were not always present in the first hours after birth, we determined discriminative cut-offs for mean OSI values already in these first hours for pulmonary hypertension, the need for ECMO-therapy, and mortality. CONCLUSIONS: Continuous OSI evaluation is a promising modality to identify those infants at highest risk for clinical deterioration already in the first hours after birth. This provides an opportunity to tailor postnatal management based on the individual patient's needs.

Spontaneous breathing approach in mild congenital diaphragmatic hernia: A resuscitation algorithm.

Background: Infants with a congenital diaphragmatic hernia (CDH) and expected mild pulmonary hypoplasia have an estimated survival rate of 90%. Current guidelines for delivery room management do not consider the individual patient's disease severity, but an individualized approach with spontaneous breathing instead of routine mechanical ventilation could be beneficial for the mildest cases. We developed a resuscitation algorithm for this individualized approach serving two purposes: improving the success rate by structuring the approach and providing a guideline for other centers. Methods: An initial algorithm was discussed with all local stakeholders. Afterwards, the resulting algorithm was refined using input from international experts. Results: Eligible CDH infants: left-sided defect, observed to expected lung-to-head ratio ≥50%, gestational age at birth ≥37.0 weeks, and no major associated structural or genetic abnormalities. To facilitate fetal-to-neonatal transition, we propose to start stabilization with non-invasive respiratory support and to adjust this individually. Conclusions: Infants with mild CDH might benefit from an individualized approach for neonatal resuscitation. Herein, we present an algorithm that could serve as guidance for centers implementing this.

Physiological-based cord clamping versus immediate cord clamping for infants born with a congenital diaphragmatic hernia (PinC): study protocol for a multicentre, randomised controlled trial.

INTRODUCTION: Pulmonary hypertension is a major determinant of postnatal survival in infants with a congenital diaphragmatic hernia (CDH). The current care during the perinatal stabilisation period in these infants might contribute to the development of pulmonary hypertension after birth-in particular umbilical cord clamping before lung aeration. An ovine model of diaphragmatic hernia demonstrated that cord clamping after lung aeration, called physiological-based cord clamping (PBCC), avoided the initial high pressures in the lung vasculature while maintaining adequate blood flow, thereby avoiding vascular remodelling and aggravation of pulmonary hypertension. We aim to investigate if the implementation of PBCC in the perinatal stabilisation period of infants born with a CDH could reduce the incidence of pulmonary hypertension in the first 24 hours after birth. METHODS AND ANALYSIS: We will perform a multicentre, randomised controlled trial in infants with an isolated left-sided CDH, born at ≥35.0 weeks. Before birth, infants will be randomised to either PBCC or immediate cord clamping, stratified by treatment centre and severity of pulmonary hypoplasia on antenatal ultrasound. PBCC will be performed using a purpose-built resuscitation trolley. Cord clamping will be performed when the infant is considered respiratory stable, defined as a heart rate >100 bpm, preductal oxygen saturation >85%, while using a fraction of inspired oxygen of <0.5. The primary outcome is pulmonary hypertension diagnosed in the first 24 hours after birth, based on clinical and echocardiographic parameters. Secondary outcomes include neonatal as well as maternal outcomes. ETHICS AND DISSEMINATION: Central ethical approval was obtained from the Medical Ethical Committee of the Erasmus MC, Rotterdam, The Netherlands (METC 2019-0414). Local ethical approval will be obtained by submitting the protocol to the regulatory bodies and local institutional review boards. TRIAL REGISTRATION NUMBER: NCT04373902.

Oxygen Saturation Index in Neonates with a Congenital Diaphragmatic Hernia: A Retrospective Cohort Study.

INTRODUCTION: The oxygenation index (OI) is a marker for respiratory disease severity and adverse neonatal outcomes. The oxygen saturation index (OSI) is an alternative that allows for continuous noninvasive monitoring, but evidence for clinical use in critically ill neonates is scarce. The aim of this study was to evaluate the OSI as compared to the OI in term neonates with a congenital diaphragmatic hernia (CDH). METHODS: A single-center retrospective cohort study was conducted including all live-born infants with an isolated CDH between June 2017 and December 2020. Paired values of the OI and OSI in the first 24 h after birth were collected. The relation between OI and OSI measurements was assessed, taking into account arterial pH, body temperature, and preductal versus postductal location of oxygen saturation measurement or arterial blood sampling. The predictive values for pulmonary hypertension, need for extracorporeal membrane oxygenation therapy, and survival at discharge were evaluated. RESULTS: Of 33 subjects included, 398 paired values of the OI (median 5.8 [3.3-17.2]) and OSI (median 7.3 [3.6-14.4]) were collected. The OI and OSI correlated strongly (r = 0.77, p < 0.001). The OSI values corresponding to the clinically relevant OI values (10, 15, 20, and 40) were 8.9, 10.9, 12.9, and 20.9, respectively. The predictive values of the OI and OSI were comparable for all adverse neonatal outcomes. No difference was found in the area under the receiver operating characteristic curves for the OI and the OSI for adverse neonatal outcomes. CONCLUSIONS: The OSI could replace the OI in clinical practice in infants with a CDH.

Knowledge Gaps in the Fetal to Neonatal Transition of Infants With a Congenital Diaphragmatic Hernia.

Clinical research for infants born with a congenital diaphragmatic hernia (CDH) has until recently mainly focused on advances in prenatal and postnatal treatment. However, during the early perinatal transition period there are major physiological adaptations. For most infants these changes will happen uneventfully, but for CDH infants this marks the beginning of serious respiratory complications. In recent years, there is emerging evidence that the clinical management during the perinatal stabilization period in the delivery room may influence postnatal outcomes. Herein, we discuss major knowledge gaps and novel concepts that aim to optimize fetal to neonatal transition for infants with CDH. One such novel and interesting approach is performing resuscitation with an intact umbilical cord, the efficacy of this procedure is currently being investigated in several clinical trials. Furthermore, close evaluation of neonatal physiological parameters in the first 24 h of life might provide early clues concerning the severity of lung hypoplasia and the risk of adverse outcomes. We will provide an overview of trending concepts and discuss potential areas for future research.

Implementation of Delayed Cord Clamping for 3 Min During Term Cesarean Sections Does Not Influence Maternal Blood Loss.

Background: To assess maternal safety outcomes after a local protocol adjustment to change the interval of cord clamping to 3 min after term cesarean section. Design, Setting, and Patients: A retrospective cohort study in a tertiary referral hospital (Erasmus MC, Rotterdam). We included pregnant women who gave birth at term after cesarean section. A cohort (Nov 2016-Oct 2017) prior to the protocol implementation was compared to a cohort after its implementation (Nov 2017-Nov 2018). The study population covered 789 women (n = 376 pre-cohort; n = 413 post-cohort). Interventions: Implementation of a local protocol changing the interval of cord clamping to 3 min in all term births. Main outcome measures: Primary outcomes were the estimated maternal blood loss and the occurrence of postpartum hemorrhage (blood loss >1,000 ml). Secondary outcomes included both maternal as well as neonatal outcomes. Results: Estimated maternal blood loss was not significantly different between the pre-cohort and post-cohort (400 mL [300-600] vs. 400 mL [300-600], p = 0.52). The incidence of postpartum hemorrhage (26 [6.9%] vs. 35 (8.5%), OR 1.24, 95% CI 0.73-2.11) and maternal blood transfusion (9 [2%] vs. 13 (3%), OR 1.33, 95% CI 0.56-3.14) were not different. Hemoglobin change was significantly higher in the post-cohort (-0.8 mmol/L [-1.3 to -0.5] vs. -0.9 mmol/L [-1.4 to -0.6], p = 0.01). In the post-cohort, neonatal hematocrit levels were higher (51 vs. 55%, p = 0.004) and need for phototherapy was increased (OR 1.95, 95% CI 0.99-3.84). Conclusion: Implementation of delayed cord clamping for 3 min in term cesarean sections was not associated with increased maternal bleeding complications.

Perinatal stabilisation of infants born with congenital diaphragmatic hernia: a review of current concepts.

Congenital diaphragmatic hernia (CDH) is associated with high mortality rates and significant pulmonary morbidity, mainly due to disrupted lung development related to herniation of abdominal organs into the chest. Pulmonary hypertension is a major contributor to both mortality and morbidity, however, treatment modalities are limited. Novel prenatal and postnatal interventions, such as fetal surgery and medical treatments, are currently under investigation. Until now, the perinatal stabilisation period immediately after birth has been relatively overlooked, although optimising support in these early stages may be vital in improving outcomes. Moreover, physiological parameters obtained from the perinatal stabilisation period could serve as early predictors of adverse outcomes, thereby facilitating both prevention and early treatment of these conditions. In this review, we focus on the perinatal stabilisation period by discussing the current delivery room guidelines in infants born with CDH, the physiological changes occurring during the fetal-to-neonatal transition in CDH, novel delivery room strategies and early predictors of adverse outcomes. The combination of improvements in the perinatal stabilisation period and early prediction of adverse outcomes may mitigate the need for specific postnatal management strategies.