Delivery room and early postnatal management of neonates with congenital heart disease

Advancements in prenatal detection have improved postnatal outcomes for patients with congenital heart disease (CHD). Detailed diagnosis during pregnancy allows for preparation for the delivery and immediate postnatal care for the newborns with CHD. Most CHDs do not result in hemodynamic instability at the time of birth and can be stabilized following the guidelines of the neonatal resuscitation program (NRP). Critical CHD that requires intervention immediately after birth is recommended to be delivered in facilities where immediate neonatal and cardiology care can be provided. Postnatal stabilization and resuscitation for these defects warrant deviation from the standardized NRP. For neonatal providers, knowing the diagnosis of fetal CHD allows for preparation for the anticipated instability in the delivery room. Prenatal detection fosters collaboration between fetal cardiology, cardiology specialists, obstetrics, and neonatology, improving outcomes for neonates with critical CHD.

access to prenatal diagnosis of CCHD and timely postnatal management.
5][6] Newborns with D-transposition of the great arteries (DTGA) and hypoplastic left heart syndrome with restrictive or closed atrial septum (HLHS restricted atrial septum [RAS]/intact atrial septum [IAS]) have inadequate oxygen delivery to the tissues after birth, resulting in refractory hypoxia and metabolic acidosis. 7In one study, fetal echocardiography reduced the mortality of neonates with DTGA without changes in pregnancy termination. 8In addition, the fetal detection of CCHD, including DTGA and defects with single ventricle (SV) physiology, has been shown to reduce postnatal end-organ failure and neurological injury. 7,9e Neonatal Resuscitation Program (NRP) guidelines were created for delivery room (DR) care of all newborns and are not diagnosis-specific, including being used for the resuscitation of newborns with CHD. 10 Most CHD does not require alterations in the neonatal resuscitation algorithm for stabilization; however, for newborns with specific CCHD, NRP guidelines are inadequate and potentially detrimental and therefore need modification. 11,124][15][16][17][18] This review highlights the use of prenatal diagnosis for pre-delivery, DR planning, modifications in resuscitation, and immediate postnatal stabilization for neonates with CHD.

| PRENATAL MANAGEMENT OF THE FETUS WITH KNOWN CONGENITAL HEART
A list of high-risk fetal or maternal indications generates a direct referral to a fetal cardiologist for fetal echocardiography for CHD screening. 19Otherwise, in most instances, CHD is suspected by the obstetrician or maternal-fetal medicine specialist during the anatomy scan and then confirmed by a fetal cardiologist.Once the diagnosis is made, multiple specialists become involved in prenatal counseling and management. 204][15] Specifics of the birth plan, including delivery location, timing, method (vaginal vs. cesarean delivery), presence of additional personnel and resources in the DR, and postnatal disposition, are made depending on the likelihood of hemodynamic instability after birth. 13,21,22

| TIMING, LOCATION, AND MODE OF DELIVERY
The placenta maintains the hemodynamic stability of a fetus with CHD; therefore, a cardiac anomaly alone infrequently determines the delivery timing.On rare occasions when the placenta is unable to maintain hemodynamic stability, fetal cardiac dysfunction progresses to hydrops, an accumulation of fluid in various body cavities.For these cardiac lesions, delivery timing is dictated by worsening hydrop refractory to medical management, and in some cases, results in preterm delivery.
Neonates with CCHD delivered at the gestational age of 39-40 weeks have lower morbidity and mortality in comparison to those delivered preterm. 23Prematurity in combination with CHD worsens outcomes.For some cardiac lesions, prematurity may result in the inability to perform surgical or catheter interventions.In other cases, changes secondary to prematurity, such as the development of bronchopulmonary dysplasia, may affect oxygenation and perfusion, impacting hemodynamic stability and neurodevelopmental outcomes.Some specialized fetal centers have created an "all in one place" medical care model for high-risk patients where all required resources for both mother and baby are available in one location. 24livery of babies with high-risk fetal anomalies at these specialized fetal care centers eliminates the need for transport of the baby from the delivery facility and decreases the time required for interventions. 25Despite the potential to improve patient outcomes, these facilities with highly orchestrated care models are not readily available.In some parts of the world and some areas in the US, access to necessary prenatal and neonatal care is limited or nonexistent. 1,26ailability of specialized medical care shortly after birth is not essential for survival in most cases of CHD.Mortality, however, of certain CHD is high without intervention for stabilization immediately after birth.[28] In the American Heart Association guidelines for diagnosing and treating fetal cardiac disease, Donofrio et al. ranked CHD into four level of care (LOC) categories based on the possibility of instability at birth. 16C 1 is at low risk for DR compromise and includes atrial or ventricular septal defect or atrioventricular septal defect that is stable for the first few weeks of life.Without needing specialized DR or immediate postnatal care, outpatient cardiology follow-up is recommended.LOC 2 is medium risk and includes defects most often ductal-dependent, such as severe tetralogy of Fallot (TOF) or CHD with a SV and either pulmonary or aortic outflow obstruction.These babies are stable in DR, though they need medical or surgical intervention postnatally before discharge.Recommendations for babies with CHD include delivery at a facility staffed with a neonatologist and postnatal transfer to a facility with pediatric cardiology surgical services.Care of these infants may warrant NRP modifications, such as targeting different preductal oxygen saturation goals. 29itiation of prostaglandin (PGE) is usually required, and postnatal cardiology and surgery are needed for CHD in this category. 12,15,30gh-risk defects in LOC 3 are likely, and 4 are expected to be unstable at birth and require specialized medical and/or surgical intervention immediately after delivery, often initiated in the DR. 12,15,31It is recommended that delivery of these babies should occur at a facility equipped with resources and personnel, including a neonatologist, cardiologists, cardiac interventionist, and cardiac 916 -ALI and DONOFRIO surgeon.These high-risk diagnoses include unstable arrhythmias with cardiac dysfunction or hydrops, HLHS and variants with a RAS/IAS, DTGA, TOF with absent pulmonary valve, Ebstein anomaly with heart failure or hydrops, and any other defect with poor cardiac function at birth. 15,16,18(Table 1) For babies with CHD with no available intervention or if the family is pursuing palliative care, the primary care team should decide the best delivery location to support the family.
7][18] Cesarean delivery is not needed for most prenatally diagnosed CHDs as most fetuses with CHD can tolerate labor. 21When compared, complications from labor and vaginal delivery were not different when comparing babies with HLHS to normal controls. 32In addition, fetal acidosis secondary to nonreassuring fetal heart tones was similar in CHD and non-CHD patients. 31For defects that are LOC 3 and 4, scheduled cesarean delivery may be beneficial to ensure proper resources and personnel are present at the time of birth. 16,21e risk stratification model described was created to develop specific protocols for DR management of prenatally diagnosed CHD and has been used in clinical practice. 18A multidisciplinary team created and implemented standardized practice guidelines specifying timing and location of delivery and resuscitation specifics, including oxygen saturation goals and use of medications and/or procedures that are not part of routine NRP.In this single-institution study, it was demonstrated that the feasibility of implementation of DR protocols and patient care improvement could be achieved.
Multicenter studies are needed to investigate whether specialized stabilization protocols for cardiac defects improve not only DR resuscitation but also the long-term outcomes of neonates with CHD. 33,34

| PREPARATION FOR DELIVERY
Over 4 million babies are born annually in the United States, and 90% transition to ex-utero circulation independently. 35The neonatal DR resuscitation algorithm substantiated by decades of evidence is largely centered around the term neonate.Recently, NRP has expanded to include modifications in the algorithm for special conditions. 10However, there is a lack of guidelines on DR resuscitation and stabilization of CHD and/or arrhythmia management with severe cardiac dysfunction or heart failure.Like infants with normal hearts, most newborns with CHD transition to neonatal circulation without assistance. 12[14][15][16] The American Academy of Pediatrics suggests that at least two NRP-trained providers should be present at all deliveries and additional personnel should be in attendance for high-risk births. 10ving information on the gestational age, rupture of membranes, color of amniotic fluid, and plan for delayed cord clamping prepares T A B L E 1 Delivery planning and NRP modifications for complex congenital heart defects.
the providers for the stabilization of the baby and determines the possibility of resuscitation needed in the DR. 10,36e infant's gestational age at the time of birth is one of the main determinants for having additional resources in the DR.Once delivered, the premature infant loses amniotic fluid protection, and the highly permeable skin is susceptible to hypothermia and vasoconstriction. 37Preparation of preterm birth involves having available appropriate-size resuscitation and thermoregulation equipment and additional neonatal providers. 38Placental separation, surfactant deficiency, underdeveloped gas exchange units, and a noncompliant cardiovascular system are inadequate to maintain oxygenation and perfusion in preterm infants. 391][42] Finally, the preterm delivery of certain CHD may limit options for immediate and future postnatal cardiac interventions, and decisions regarding resuscitation should take this into account.
The timing of membrane rupture and the color of the amniotic fluid influence postnatal stability.The absence of amniotic fluid in the early gestation halts lung development, resulting in hypoplastic lungs that may not establish or sustain adequate gas exchange. 43,44Prolonged rupture of membranes increases the risk of neonatal sepsis through vertical transmission.After being separated from the placenta, the septic newborn is at risk of cardiovascular collapse because of the incapability to generate appropriate cardiac output.Fetal stress or asphyxia produces acidosis, triggers in-utero passage of meconium, and increases fetal respiration, risking meconium aspiration. 45idence supports the neonatal benefits of delayed cord clamping, and American college of obstetricians and gynecologists recommends a 30-60-s delay in cord clamping for all term infants. 46ntinued attachment to the placenta as ventilation and neonatal circulation are established preserves stable hemodynamics.[49]

| DELIVERY RESUSCITATION AND STABILIZATION
With the first breath, the neonatal alveoli stretch and expel the remainder of the fetal lung fluid while the diaphragm contracts to expand the lungs.The functional residual capacity increases with each breath, allowing for more gas exchange and decreasing pulmonary vascular resistance (PVR).In most instances, the increase in systemic vascular resistance after cord clamping reverses blood flow through the ductus arteriosus and foramen ovale, increasing blood flow to the lungs. 50Successful transition to neonatal circulation depends on this highly orchestrated interplay between the neonatal lungs and changes in cardiac circulation.The transition efficiency to neonatal circulation is evident by the rise in neonatal oxygen saturation from 60% at birth to 90% by just 5 min of life. 51e first steps of NRP include positioning, drying, and stimulation to establish ventilation and maintain perfusion.Infants are placed in a sniffing position to optimize airway opening, and if needed, oral and nasal secretions are cleared using a bulb suction.Drying the baby decreases heat loss to ambient air and stimulates the infant's breathing drive.If these initial steps fail to establish adequate ventilation, respiratory support with either blowing by oxygen, continuous positive airway pressure, or positive pressure ventilation is delivered, depending on the degree of respiratory distress.Heart rate and preductal pulse oximetry are monitored since progression through the NRP algorithm depends on changes in heart rate as a response to intervention. 10If these early interventions fail to improve ventilation and/or increase the heart rate to a normal range, NRP recommends corrective ventilation steps, including readjusting the mask, ensuring airway patency, increasing the airway pressure being delivered, and using an advanced airway with either endotracheal tube or laryngeal mask airway NRP prioritizes ventilation since perinatal asphyxia is a common cause hindering the transition to neonatal circulation. 52In most instances, corrective ventilation steps prescribed in NRP are sufficient to establish and support neonatal breathing and circulation, including for neonates with CHD (Figure 1A).Of the 10% of neonates that require resuscitation in the DR, 99.9% achieve stabilization after receiving corrective ventilation steps, and less than 0.1% go on to need chest compression and epinephrine. 53rrently, NRP does not include modifications for the algorithm for neonates with CHD.Most CHDs fall into the low-and medium risk (LOC 1 and 2) categories and are not expected to become symptomatic immediately after birth.Standard NRP guidelines should be followed in the DR with limited modifications for these defects.Adjustments to the targeted oxygen saturation goals are anticipated and should be followed when intracardiac mixing of venous and arterial blood is expected, such as in SV CHD, including HLHS, to maintain a balance between the pulmonary and systemic blood flow. 54Additional components of DR stabilization include establishing vascular access for most newborns with CHD that are at medium or high risk (LOC 2, 3, and 4).Vascular access, including peripheral IV or a low-lying umbilical vein catheter (UVC), is required to administer specific potentially life-saving medications.If vascular access is used to administer PGE, it may be obtained in the neonatal intensive care unit since it is unlikely that the patent ductus arteriosus will close immediately after delivery.A low-lying UVC is placed for medications required to maintain stability immediately in the DR.
Isoproterenol, continuous epinephrine infusion, after intubation sedation, and neuromuscular blockade are some examples of potentially life-saving medications that may be needed immediately after birth in neonates with high-risk CCHD (LOC 3 and 4).Deviation from NRP is necessary for high-risk CCHD (LOC 3 and 4) categories that are at risk for hypoxia and acidosis after delivery and require specific postnatal interventions that are not discussed in NRP. 12,15,16DR care impacts morbidity, including end-organ injury, as well as overall mortality for these high-risk patients.The brain is particularly vulnerable.A retrospective study of ductal-dependent CHD found that hypoxia and acidosis in the first few minutes of life led to a longer duration of mechanical ventilation, increased 918 -ALI and DONOFRIO cerebral hemorrhage, and a 42% increase in overall mortality. 55enatal diagnosis of these high-risk CCHDs allows for preparation to modify NRP and plan specific medical or surgical interventions to achieve hemodynamic stability, prevent neurological injury, and improve survival.CCHDs in these categories include HLHS with RAS/ IAS, obstructed total anomalous pulmonary venous return (TAPVR), DTGA with an intact ventricular septum, severe forms of TOF with an absent pulmonary valve, severe Ebstein anomaly, and uncontrolled fetal arrhythmias with severe cardiac dysfunction or hydrops.After separation from the placenta, these babies require more than standard NRP care, and if specific interventions are not performed promptly after delivery, significant morbidity and an increased risk of mortality are likely. 13,16,22,33There is a lack of evidence regarding long-term outcomes determining the optimal resuscitation algorithm.
Recommendations below are suggested based on anticipated risks and causes of decompensation in the DR (Table 1) (Figure 1B).

| HLHS with RAS/IAS
In a fetus with HLHS, the single right ventricle delivers blood to the systemic circulation.There is minimal pulmonary blood flow that reaches the lungs, drains into the left atrium, and must pass through the foramen ovale back to the systemic circulation.7][58] At delivery, there is an increase in the oxygenated blood from the lungs entering into the left atrium by pulmonary veins and then delivered to the systemic circulation by the left ventricle.Newborns with HLHS rely on the patency of the foramen ovale to shunt oxygenated blood to the right atrium and deliver it to the systemic circulation through the right ventricle.
Newborns with HLHS and restricted or intact atrial septum will have a rapid onset of pulmonary venous congestion and edema, resulting in hypoxia further progressing to metabolic acidosis DR planning should include anticipation of postnatal instability. 59Rapid transfer to a cardiac center.That can perform cardiac catheterization with atrial septoplasty is needed in these infants. 60,61In some instances, extracorporeal membrane oxygenation (ECMO) may be initiated before intervention.Of note is that if the lungs are abnormal due to long-standing utero injury, including fetal magnetic resonance imaging suggesting pulmonary lymphangiectasia, there is a very high likelihood of mortality. 62,63onatal resuscitation providers attending the delivery of babies with HLHS and RAS/IAS should plan to stabilize the hypoxic and acidotic newborn using interventions beyond the guidelines of NRP.
After delivery, NRPs initial positioning and drying steps can be followed.Intubation with mechanical ventilation, using sedation and neuromuscular blockade, is planned to achieve stability before transfer for intervention.Supplemental oxygen may be used with extreme caution, though only as needed to achieve the predetermined oxygen saturation goal to prevent brain injury.[14][15][16]

| DTGA with intact ventricular septum
In the fetus with DTGA, the blood entering the aorta (and thus perfusing the brain) has lower oxygen content, and the blood that enters the pulmonary artery has higher than normal oxygen content if the foramen ovale is open.This is believed to decrease PVR and possibly cause ductal constriction, increasing pulmonary blood flow and left atrial pressure, resulting in foramen ovale restriction. 63At delivery, the sudden and rapid further decrease in PVR and a significant increase in pulmonary blood flow may lead to more significant or new foramen ovale restriction or closure, which then results in inadequate delivery of oxygen-rich blood to the systemic circulation, causing hypoxia and acidosis despite patency of the ductus arteriosus .64,65In addition, alterations in pulmonary blood flow in utero may also increase the risk of pulmonary hypertension after delivery, further exacerbating hypoxia, particularly in the preductal circulation including the brain. 63,66,67(Figure 1A,B) Fetal echocardiography findings predicting foramen ovale closure in the DR are currently unreliable; hence, providers attending the delivery should be prepared for the possibility of neonatal compromise. 67,68Cardiac interventionalists should be notified about a DTGA delivery in the event that balloon atrial septostomy (BAS) is warranted.
Neonatal resuscitation providers attending the delivery of babies with DTGA should plan to stabilize the hypoxic and acidotic newborn using interventions beyond the guidelines of NRP.After delivery, the initial steps of NRP, positioning, drying, and stimulation can be followed.If the neonate is hypoxic, does not respond to supplemental oxygen, and/or has low perfusion, preparation to perform an emergent BAS should be made.In some institutions, this can be facilitated in the DR, whereas others require immediate transfer to a different location within the hospital or a different facility for cardiac intervention. 12In the event of hypoxia not responsive to supplemental oxygen, intubation with mechanical ventilation, sedation, and neuromuscular blockade may be necessary to achieve stability.
Inhaled nitric oxide should be considered if there is differential cyanosis with upper extremity hypoxia, putting the brain at risk of cerebral injury. 67,69

| TOTAL ANOMALOUS PULMONARY VENOUS RETURN (TAPVR)
With the diagnosis of TAPVR, none of the pulmonary veins enter the left atrium but return to the systemic venous circulation via a connection that may be obstructed.1][72] The lack of pulmonary blood flow permits in-utero tolerance of anomalous pulmonary venous return.However, as in HLHS with RAS/IAS, it may damage the lungs if the pathway is obstructed.The rare occurrence of TAPRV and the challenges in visualizing fetal pulmonary veins affect prenatal detection. 73ter separation from the placenta, neonatal hemodynamics depends on the proper vascular connections between the systemic and pulmonary venous circulations and the heart.Inadequate left ventricular preload diminishes the output of oxygenated blood to the systemic circulation and causes profound hypoxia and subsequent acidosis unresponsive to NRP resuscitation steps. 12[15][16]

| TOF WITH ABSENT PULMONARY VALVE
In contrast, in the rare diagnosis of TOF with an absent pulmonary valve, if severe, the hypoxia noted after delivery is not due to decreased pulmonary blood flow but secondary to lung abnormalities from tracheobronchial compression from dilated branch pulmonary arteries due to severe pulmonary regurgitation.Of note is that in most instances, the ductus arteriosus is absent.
Immediately after delivery, the position, drying, and stimulation can be trialed to stabilize the neonate with TOF and absent pulmonary valve.Positioning the infant in a prone position may be 920 -ALI and DONOFRIO considered if there are mild signs of respiratory distress. 75With significant respiratory distress, intubation with mechanical ventilation is needed, though since there is a risk for air trapping and possible lung hypoplasia, caution should be taken regarding the pressure delivered via assisted ventilation.The dilated right ventricle is at risk for dysfunction, especially if there is an elevated PVR. 67livering 100% FiO2 and possibly inhaled nitric oxide can be considered in situations with severe hypoxia.Of note, prostaglandin should not be initiated given the congenital absence of the ductus arteriosus.

| EBSTEIN ANOMALY
The fetus with severe Ebstein anomaly will have a severely dilated right atrium due to tricuspid regurgitation. 76The right ventricular cavity may be small despite dilation due to displacement of the valve annulus.This may result in right ventricular dysfunction, elevated systemic venous pressure, no forward flow across the pulmonary valve, and reversed ductal flow. 76,77Also, left ventricular dysfunction may be present from right ventricular compression or abnormal myocardium.If there is associated pulmonary valve insufficiency, reversed ductal flow may "steal" blood from the systemic circulation. 75As a result of the severe hemodynamic derangement, fetal heart failure, and hydrops may occur, particularly if there is pulmonary insufficiency or right or left ventricular dysfunction present.
At delivery, newborns with severe Ebstein anomaly may present with severe hypoxia, poor perfusion, acidosis, and possible arrhythmias due to the dilated right atrium and increased risk of associated Wolf Parkinson White syndrome. 78The poorly functioning right ventricle may be unable to generate adequate flow to the lungs.
Hypoxia may be exacerbated by compression of the lungs and difficulty in lung expansion due to cardiomegaly.The decreased cardiac output to the systemic circulation is a combination of decreased cardiac output from the left ventricle due to compression or myocardial dysfunction as well as possible "steal" of systemic blood flow through the ductus arteriosus in the presence of pulmonary insufficiency. 79r known severe Ebstein anomalies, postnatal stabilization can begin with the initial steps of NRP.If the hypoxia is unresponsive to the correct ventilation steps, then increased pressures should be used to ventilate to overcome the effect of cardiomegaly on lung inflation.Intubation with ventilation using supplemental O 2 to overcome severe hypoxia and prevent brain injury should be initiated.In the presence of pulmonary insufficiency, prostaglandin should be avoided, and supplemental oxygen and other pulmonary vasodilators should be limited and used with caution, given that they may exacerbate the systemic steal from the ductus arteriosus. 80In addition, the choice and dosing of inotrope support for the resulting hypotension should be monitored since the resultant tachycardia from these medications can decrease the threshold for arrhythmia.

| CONGENITAL HEART BLOCK
Fetal heart block may be associated with CCHD, though in many cases, there is a structurally normal heart, and bradycardia is due to a maternal autoimmune condition with positive Sjogren's syndromerelated antigen A antibody titers. 81If fetal bradycardia is detected prenatally, steroids and intravenous immunoglobulin may be used to prevent associated myocardial injury, though further work is needed to determine efficacy. 82,83In most instances, a fetus with normal heart function can tolerate fetal bradycardia to rates as low as 50-55 bpm; however, if the cardiac function becomes compromised or the ventricular rate is lower, then the fetus is at risk for developing hydrops.Consultation with an electrophysiologist is essential in managing these patients, particularly in situations requiring pacing.
Preparation for the birth of a baby with fetal bradycardia due to heart block depends on whether there is associated fetal compromise.If there is an adequate ventricular rate and normal heart function, NRP guidelines can be used, noting that the baseline heart rate is lower than normal.If, however, there are associated cardiac dysfunction and fetal compromise or hydrops, then delivery should occur at a facility where cardiac intervention can occur.Initial resuscitation in the compromised newborn should include intubation, sedation, and neuromuscular blockade to minimize oxygen demand.Initial heart rate control can usually be achieved with either epinephrine or isoproterenol.Sometimes, a temporary pacemaker may be placed depending on institutional practice.[86]

| FETAL TACHYARRHYTHMIAS/ SUPRAVENTRICULAR TACHYCARDIA AND ATRIAL FLUTTER
[89] In situations where medical therapy is unsuccessful and fetal compromise develops, including hydrops, early delivery may be considered. 90Management of the compromised neonate with fetal tachyarrhythmia should include initial NRP guidelines.Electrocardiography leads or defibrillator pads should be immediately applied.
Escalation of respiratory support will depend on the infant's condition at birth and whether hydrops is present.Vascular access should be established through peripheral IV or umbilical lines.[93]

| CONCLUSION
The prenatal diagnosis of CHD allows for better fetal surveillance during pregnancy and the planning of specialized care at the time of delivery.Information about the specific CHD, anticipated postnatal ALI and DONOFRIO -921 physiology, heart rhythm and function, and possible associated complications allows neonatal providers to collaborate with cardiology providers to prepare for postnatal stabilization.In most cases, NRP guidelines can be followed for DR stabilization; however, in cases of CCHD, significant planning with specialized care is needed to improve outcomes.

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I G U R E 1 (A) Factors contributing to postnatal instability not associated with underlying congenital heart disease.(B) Fetal to neonatal transitional circulation in high-risk congenital heart disease.