Preoperative Care of Neonates With Congenital Heart Disease

Abstract

Congenital heart disease (CHD) is one of the most common types of birth defects, with 40,000 newborns diagnosed yearly in the United States. This article describes: (1) four common heart defects seen in neonatal intensive care units, (2) the typical medical/nursing care of these neonates, and (3) common surgical management for the defects. Hypoplastic left heart syndrome, dextro-transposition of the great arteries, tetralogy of Fallot, and pulmonary atresia with intact ventricular septum are four common types of CHD requiring NICU admission. Knowledge of these defects will help nurses to appropriately manage and treat neonates with these types of CHD.

Congenital heart disease (CHD) remains one of the most common birth defects in the United States, affecting 40,000 newborns each year.¹ We describe four common types of complex CHD seen in neonatal intensive care units (NICUs). Identification of CHD during the fetal or neonatal period is crucial for survival, prompting medical and eventual surgical interventions to facilitate oxygenation and circulation to the body and major organs.

The heart maintains a constant flow of blood which carries essential nutrients and oxygen throughout the body.² Normally, blood flows one way through the right atrium, tricuspid valve, right ventricle (RV), pulmonary valve, and pulmonary artery to the lungs where deoxygenated blood becomes oxygenated.² Blood returns from the lungs and then flows through the pulmonary veins to the left atrium, through the mitral valve to the left ventricle (LV), and is finally ejected out of the aortic valve to the aorta, which supplies oxygenated blood throughout the body (Figure 1).² Structural defects of the heart or its vessels disrupt the normal route of blood flow, which can interrupt flow to the pulmonary or systemic circulation.³

FIGURE 1. Blood flow and anatomy of a normal heart.

Source: Courtesy of Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities. Normal Heart. https://www.cdc.gov/ncbddd/heartdefects/images/normal-heart-550px.jpg

Neonates with critical forms of CHD are often diagnosed prenatally; this can facilitate the plans for care and postnatal management. Several studies have found that prenatal diagnosis of CHD has reduced the likelihood of preoperative morbidity and mortality,⁴ and although research is still unclear, some studies found a reduction in postoperative mortality as well.^5,6 Preoperative care of neonates diagnosed with CHD typically consists of assessment, management, treatment, and evaluation of symptoms before surgical intervention.⁷ Management can involve medications, supplemental oxygen, intubation, and mechanical ventilation to stabilize the neonate.⁸ Moreover, children with cardiac defects are at higher risk for brain injury and developmental delays. Therefore, early identification and treatment for heart defects may improve outcomes for this high-risk population by mitigating future neurologic problems. Furthermore, neonatal nurses facilitate two-way communication between caregivers and the medical team and provide constant support and advocacy for the patient and family.^9,10 Thus, preoperative measures are important, such as immediate non-surgical and medical treatments and/or early diagnosis, to decrease the risk of complications during the perioperative or postoperative phase which improves outcomes for this vulnerable population.

CRITICAL CONGENITAL HEART DISEASE SCREENING

Screening for critical CHD has been instrumental in detecting undiagnosed heart defects in newborns. This has decreased morbidity and mortality because most heart defects can be treated medically or surgically.¹¹ The current recommendation for pulse oximetry screenings prior to neonatal hospital discharge detects most forms of critical CHD.^12,13 Thus, screening is routinely performed at approximately 24 hours of life for most neonates in the newborn nursery.^12,13 A pulse oximeter is placed on the neonate’s right hand (preductal) and a second pulse oximeter is placed on a lower extremity (postductal) to measure oxygen saturation of blood before and after the ductus arteriosus. The neonate “passes” the screen if the oxygen saturation values are greater than 95 percent and there is less than a 3 percent difference between to the two. A “retest” happens when pre- and postductal oxygen saturations are between 90 and 94 percent or there is ≥4 percent difference between the pre- and postductal oxygen saturation values. The second test is performed 1 hour after the initial screening. A third test is done if the results of the second test are the same as described for the initial “retest.” If the results are unchanged, then the provider would perform a clinical assessment to rule out CHD. A “failure” occurs if the oxygen saturation value is less than 89 percent in either the pre- or postductal measurements. The neonate will be referred to a cardiologist for further evaluation. An echocardiogram will be done in order to rule out a heart defect.¹⁴

COMMON TYPES OF CONGENITAL HEART DISEASE DIAGNOSED IN THE FETAL AND NEONATAL PERIODS

The severity of CHD varies. Approximately 10.3/1,000 live births involve a minor form of CHD; 2.6/1,000 live births, a moderate form of CHD; and 2.3/1,000 live births have a severe form of CHD.¹⁵ Four common types of severe CHD treated in NICUs are hypoplastic left heart syndrome (HLHS), having a prevalence of 1,000 births in the U.S. each year;¹⁰ dextro-transposition of the great arteries (D-TGA) with 1,153 births/year;¹⁷ tetralogy of Fallot (TOF) with 1,660 births/year;¹⁸ and pulmonary atresia with intact ventricular septum (PA/IVS) with 550 births/year.^19-21 Types of CHD are often categorized as either cyanotic or acyanotic.¹⁹ In cyanotic heart defects, oxygenated blood mixes with deoxygenated blood, resulting in systemic arterial desaturation.^19,22 Hypoplastic left heart syndrome, D-TGA, TOF, and PA/IVS are all considered forms of cyanotic heart defects, although infants may not be severely cyanotic in the immediate neonatal period due to fetal circulation.¹⁹ The causes of these defects are not always known, but likely have genetic origins.^23-20 Additionally, it is worth noting regional differences within the United States when accounting for the distribution of the most common types of CHD. For example, newborns in the Northeast, Midwest, and South have a greater prevalence of right heart defects when compared to neonates born in Western states.²⁷

Hypoplastic Left Heart Syndrome

One of the most severe forms of CHD is HLHS, a defect that results in the underdevelopment of left-sided heart structures, including: (1) stenosis or atresia of the mitral valve, (2) hypoplasia of the LV body, (3) stenosis or atresia of the aortic valve, and (4) hypoplasia of the ascending aorta and/or aortic arch (Figure 2).²⁸ In the United States, an estimated 1,000 newborns are born with HLHS each year.¹⁶ After the transition to extrauterine life in an infant with a normal heart, the LV pumps oxygenated blood to the entire body.²⁹ When the LV develops incorrectly and cannot egress blood, oxygenated pulmonary venous blood in the left atrium is routed to the right atrium through either the foramen ovale or an atrial septal defect (ASD).¹⁶ The RV then must perfuse both systemic and pulmonary circulations as it did during fetal life.²⁸ The neonate is then dependent on patency of the ductus arteriosus postnatally to maintain systemic perfusion.¹⁶

FIGURE 2. Hypoplastic left heart syndrome.

Source: Courtesy of Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities. Hypoplastic left heart syndrome. https://www.cdc.gov/ncbddd/heartdefects/images/hlhs-web.jpg

Clinical Presentation and Assessment Findings.

Neonates with HLHS who were not diagnosed prenatally can appear normal and able to feed orally in the first few days of life.²⁸ The physical examination will reveal a murmur.³⁰ These neonates tend to have a lower birth weight than normal and a smaller head circumference.³¹ Common symptoms of HLHS include hypoxia, cyanosis, and lethargy.²⁹ Additionally, neonates with HLHS generally maintain lower oxygen saturation levels (<95 percent) compared to healthy neonates (>95 percent) because of the mixing of systemic and pulmonary circulations (Table 1).¹²

TABLE 1.

Specific Heart Defects and their Presenting Symptoms

Congenital Heart Disease Type	Presenting Structural Symptoms	Presenting Clinical Symptoms	Nursing Assessment
Hypoplastic Left Heart Syndrome	Underdevelopment of left-sided heart structures, including: (1) stenosis or atresia of the mitral valve, (2) hypoplasia of the LV body, (3) stenosis or atresia of the aortic valve, and (4) hypoplasia of the ascending aorta and/or aortic arch28	Hypoxia, cyanosis, and lethargy29 Oxygen saturation levels (<95%) because of the mixing of systemic and pulmonary circulations with the RV12	Assess and auscultate heart and lung sounds (murmur may or may not be present) Assess for increased work of breathing (nasal flaring, retractions, increased respiratory rate, or decrease in oxygen saturation) Assess for cyanosis (mucous membranes, nails, and skin) Assess central and peripheral pulses (weak pulses may be present with abnormal cardiac function) Assess for delayed capillary refill >3 seconds
Dextro-Transposition of the Great Arteries	RV leads into the aorta and the LV leads into the pulmonary artery.36,37	Cyanosis, hypoxia, and acidosis In the preoperative state, oxygen saturation = 66–88%40 Murmurs are not typically present unless a small VSD or pulmonic stenosis exists31	See above
Tetralogy of Fallot	(1) VSD, (2) pulmonary valve stenosis, (3) overriding aorta, and (4) right ventricular hypertrophy25	Cyanosis, abnormal breathing, difficulty feeding, poor weight gain, and a loud murmur upon examination if pulmonary stenosis is present.25 Blood oxygenation levels ≤80%47	See above
Pulmonary Atresia with Intact Ventricular Septum	Incomplete development of the pulmonary valve54	Cyanosis, shortness of breath, fatigue, and feeding difficulties56 In the preoperative state: blood oxygen saturation is often 65—84%58	See above

Abbreviations: LV = left ventricle; RV = right ventricle; VSD = ventricular septal defect.

Interventions and Nursing Implications.

Neonates with HLHS will die without surgical intervention to repair the heart after the PDA closes because blood cannot perfuse the body.³² Therefore, HLHS is a PDA-dependent heart lesion and maintaining a patent ductus arteriosus is required for the preservation of the systemic circulation until surgery can be performed.^12,33 The first intervention is a PGE intravenous infusion to maintain patency of the ductus arteriosus thus providing systemic blood flow via the RV.^16,28,32 If the PDA is large in size and the infant suffers from systemic vasodilation or apnea as a side effect, titration of the PGE infusion to a lower dose still able to maintain PDA patency can be efficacious. The objective of preoperative management is to keep infants on room air to maintain oxygen saturations of 75–85 percent.³³ Providing supplemental oxygen may cause pulmonary vasodilation and change the flow of blood in the heart which can cause further pulmonary overcirculation with systemic underperfusion.³⁴ Assisted or mechanical ventilation may be required due to apnea, a side effect of PGE administration. The infant may also need ventilatory assistance due to tachypnea which can result from an overload of pulmonary circulation developing as pulmonary vascular resistance falls in the first few days of life.³² Monitoring the oxygen saturation of arterial blood (SaO₂ or SpO₂) is crucial when caring for neonates with CHD who are on assisted ventilation.¹⁶ In a fully mixing heart lesion such as HLHS, the systemic blood flow can suffer as pulmonary vascular resistance falls and pulmonary flow increases. Intubation and controlled ventilation to keep arterial PCO₂ at 45–50 mmHg, can be an important measure to control pulmonary blood flow.³³ Sedation and paralysis can also limit the neonate’s metabolic demands to optimize systemic perfusion while in this critical state.¹⁶ In some cases, feeding tubes and intravenous fluids are utilized if the neonate is unable to feed orally before surgery.^28,32

While HLHS cannot be cured, orthotopic heart transplantation has been used as one form of therapy for HLHS. However, most centers recommend cardiac reconstruction as the primary and preferable treatment due to the limited number of available donor hearts.³⁵ Reconstructive palliative surgical strategies have allowed neonates with this defect to live with only the right side of the heart. Children with HLHS usually undergo a palliative three-stage surgical approach, which involves a Norwood procedure as a neonate, bidirectional Glenn shunt around 6 months of life, and a Fontan procedure at 2–4 years of age.^16,28 These surgical procedures are done in stages to allow the body to adjust to this unnatural flow of blood. During the first two weeks of life, the Norwood procedure turns the pulmonary outflow into the systemic outflow, a so-called “neoaorta,” and reconstructs the aortic arch.¹⁶ In addition, a systemic to pulmonary artery shunt or a right ventricle to pulmonary artery conduit is placed to allow a source of pulmonary blood flow of a controlled size.¹⁶ These two surgical measures create a direct connection between the systemic venous return and the pulmonary arteries, which allows deoxygenated blood to flow passively into the lower resistance pulmonary circulation, without going through the cardiac pump.

The bidirectional Glenn shunt surgery is performed between 4 and 6 months of age. It creates a direct connection between the pulmonary artery and the superior vena cava.¹⁶ The Fontan procedure, performed at roughly 2–4 years of age, connects the inferior vena cava to the pulmonary arteries and separates the deoxygenated systemic venous return from the oxygenated pulmonary venous return by allowing deoxygenated blood to go into the lungs after returning from the body.¹⁶ Children with HLHS are at risk for heart failure as well as long term disease of the lungs, liver, and gastrointestinal tract, due to the unnatural nature of their systemic RV and the passive systemic venous return of the Fontan circulation (Table 2).³⁰

TABLE 2.

Preoperative Management for Specific Heart Defects and Potential Surgical Interventions

Congenital Heart Disease Type	Preoperative Nursing Management Considerations	Surgical Intervention
Hypoplastic Left Heart Syndrome	Systemic circulation is dependent on PGE infusion to maintain a patent ductus arteriosus. Maintain patency of intravenous access for infusing PGE (if the ductus arteriosus closes completely, systemic circulation is severely reduced, and cardiovascular collapse rapidly ensues)10 Monitor respiratory status and for apnea as a side effect of PGE infusion Maintain balance between pulmonary and systemic circulations Monitor oxygen saturation of arterial blood (SaO2 or SpO2) Avoid administration of supplemental oxygen which dilates the pulmonary vascular bed. For ventilated patients, maintain PCO2 at 45–50 mmHg33 Sedation and paralysis can limit the systemic metabolic demands; thus increasing cardiac output.	Palliative three-stage surgical approach: Norwood procedure (usually performed in the first week of life) Bidirectional Glenn shunt (around 6 months of age) Fontan procedure (about 2-4 years old)11,14 Orthotopic heart transplantation
Dextro-Transposition of the Great Arteries	Monitor systemic saturation because systemic oxygenation is dependent on intracardiac mixing at the atrial level PGE infusion can promote increased pulmonary blood flow and aid left-to-right flow at the atrial septum. Monitor respiratory status and for apnea as a side effect of PGE administration Maintain balance between pulmonary and systemic circulations (see HLHS section for further detail)	Emergent balloon atrial septostomy at the bedside, in the cardiac catheterization lab, or the operating room36 Arterial switch (usually performed in the first week of life)
Tetralogy of Fallot	Monitor oxygen saturations as a marker for adequate pulmonary blood flow TOF forms with pulmonary atresia or severe pulmonary stenosis require PGE infusion to provide pulmonary blood flow (see HLHS section for discussion of PGE side effects) TOF forms with mild to moderate pulmonary stenosis require saturation assessment as the PDA closes to ensure the pulmonary blood flow is adequate. Monitor respiratory status and maintain patent airway If the neonate is discharged before surgical intervention, parents should be taught about the risk of hypercyanotic spells, including triggers for these spells, immediate interventions, and how to notify the cardiologist Initial treatment for tetralogy spells consists of placing infant in the knee-chest position, giving oxygen, and administering sedation51	Neonatal palliation with a systemic to pulmonary shunt or stenting of the PDA can be an initial surgical step44,50 Complete surgical repair to close the VSD and surgically open the pulmonary outflow usually takes place by about 6 months of age.
Pulmonary Atresia with Intact Ventricular Septum	Provide PGE infusion to allow pulmonary blood flow Monitor respiratory status and for apnea (PGE side effect) Monitor oxygen saturation as a marker of adequate pulmonary blood flow	In cases with adequate size of tricuspid valve and right ventricle, catheter-based pulmonary valvuloplasty can be curative Cases with hypoplastic tricuspid valve and right ventricle require 3-stage surgical palliation: Systemic to pulmonary artery shunt or a PDA stent Bidirectional Glenn procedure Fontan procedure Heart transplantation can be required for infants with abnormal coronary artery perfusion who are at risk for myocardial infarction

Abbreviations: HLHS = hypoplastic left heart syndrome; PCO₂ = partial pressure of carbon dioxide; PDA = patent ductus arteriosus; PGE = prostaglandin E; SaO₂/SpO₂ = oxygen saturation of arterial blood; TOF = tetralogy of Fallot; VSD = ventricular septal defect.

Dextro-Transposition of the Great Arteries

Dextro-transposition of the great arteries is another common type of complex CHD. On average, 1,153 neonates are born with D-TGA each year in the United States.¹⁷ In a normal heart, the RV pumps blood into the pulmonary artery and the LV pumps blood into the aorta. With D-TGA, however, the RV leads into the aorta and the LV leads into the pulmonary artery (Figure 3).^36,37 “Dextro” refers to the rightward and anterior position of the aortic valve in reference to the pulmonary valve.³⁷ Dextro-transposition of the great arteries results in deoxygenated blood returning from the systemic veins to the systemic arteries, and oxygenated blood from the lungs through the pulmonary veins heading back to the pulmonary artery.³⁷ Instead of the normal circulation with the systemic and pulmonary flow in series, D-TGA causes the circulation to flow in parallel so that oxygenated blood cannot reach the body. This can result in profound neonatal cyanosis after the transition from fetal circulation. Postnatally, an ASD or communication between the upper chambers of the heart is essential for mixing to allow the oxygenated blood to reach systemic circulation.^36,38 Additional anomalies can be associated with D-TGA, including a ventricular septal defect (VSD), aortic or pulmonary valve stenosis, and coarctation of the aorta.³⁶ Presence of a VSD alone generally does not allow enough mixing to prevent cyanosis.^36,37

FIGURE 3. Dextro-transposition of the great arteries.

Source: Courtesy of Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities. dextro-Transposition of the Great Arteries (d-TGA). https://www.cdc.gov/ncbddd/heartdefects/images/d-tga-575px.jpg

Clinical Presentation and Assessment Findings.

Neonates with D-TGA may appear “normal” and feed by mouth if they have good mixing of the blood through an ASD or VSD shunt (see Figure 3).³⁷ If a shunt is present, the clinician will hear a murmur.^38,39 The second heart sound is single and loud. In the preoperative state, neonates with D-TGA have low levels of blood oxygen saturation ranging from 66 to 88 percent compared to a normal value of >95 percent;⁴⁰ thus, they will appear cyanotic or dusky. When the shunts begin to close, neonates with D-TGA will exhibit symptoms such as cyanosis, hypoxia, and acidosis, putting them in extreme danger if the conditions are left untreated.³⁸ Like those with HLHS, neonates diagnosed with D-TGA also tend to have a smaller than normal head circumference (Table 1).³⁸

Interventions and Nursing Implications.

Neonates with D-TGA can have profound hypoxemia which can be fatal without emergency intervention.³⁸ A neonate who presents with inadequate atrial mixing will require an emergency procedure to open the atrial septum via balloon atrial septostomy, either at the bedside or in the cardiac catheterization laboratory (depending on the infant’s medical stability).³⁶ Additionally, preoperative care for neonates with D-TGA can include the administration of intravenous PGE to aid the mixing of oxygenated and deoxygenated blood through this systemic to pulmonary shunt.³⁸ The early use of PGE, in collaboration with a prenatal diagnosis and a highly coordinated delivery leading to immediate postnatal care at a tertiary center that specializes in treatment of neonatal CHD, lowers morbidity (e.g., preoperative brain injuries) and mortality in these neonates.⁴¹

Neonates with D-TGA generally have the arterial switch procedure in the first week of life to repair the defects.³⁷ The arterial switch operation consists of reattachment of the pulmonary artery to the RV and the aorta to the LV, as well as the relocation of the coronary arteries to the new position of the aorta.³⁷ The arterial switch procedure restores the usual blood flow in the heart and body. Cases with more complex anatomy involving additional cardiac lesions, such as a VSD or stenosis of one of the outflow tracts, may require different surgical approaches.⁴² Children with D-TGA have excellent long term outcomes after the arterial switch, but lifelong cardiac surveillance is required (Table 2).³⁷

Tetralogy of Fallot

Tetralogy of Fallot is another complex type of CHD. An estimated 1,660 neonates are born with TOF each year in the United States.¹⁸ The name “tetralogy” indicates four cardiac findings which include: (1) VSD, (2) pulmonary valve stenosis, (3) overriding aorta, and (4) right ventricular hypertrophy (Figure 4).²⁵ The defect arises because the outlet portion of the ventricular septum, which separates the aortic and pulmonary outflow tracts, becomes misaligned during embryologic development of the heart. This outlet portion of the ventricular septum is indicated by the red circle in Figure 4. The area below the pulmonary valve becomes narrowed, the aortic outflow becomes greater and spans across the ventricular septum, and the ventricular septum does not align, leaving a VSD.^43,44 The pulmonary valve may sustain varying degrees of stenosis from below the valve to the valve itself, and in the most extreme case, it does not form at all (pulmonary atresia).^43,44 The right ventricular myocardium becomes hypertrophied as the RV pumps systemically into the stenotic pulmonary outflow, as well as pumping systemically through the VSD and out the aorta.⁴⁴ In the modern era, all forms of TOF typically undergo surgical intervention during infancy, with timing dependent on the severity of the defect.²⁵ The pulmonary valve is atretic in the most severe form of TOF and needs to be treated with palliation or surgical repair during the neonatal period.^45,46

FIGURE 4. Tetralogy of Fallot.

1. Ventricular septal defect.

2. Pulmonary stenosis.

3. Overriding aorta.

4. Right ventricular hypertrophy.

Adapted from: Tetralogy of Fallot. Courtesy of Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities. https://www.cdc.gov/ncbddd/heartdefects/images/Teralogyweb.jpg

Clinical Presentation and Assessment Findings.

The symptoms of TOF include cyanosis, abnormal breathing, difficulty feeding, and poor weight gain. If pulmonary stenosis is present a loud murmur will be apparent upon examination.²⁵ Neonates with TOF can experience blood oxygenation levels of 80 percent or lower.⁴⁷ Tetralogy of Fallot can be associated with genetic syndromes such as the microdeletion of chromosome 22q11, also known as DiGeorge syndrome (Table 1).⁴⁸

Interventions and Nursing Implications.

In its severe forms, TOF causes cyanosis due to inadequate pulmonary blood flow, thus most preoperative care ensures ample systemic oxygenation via blood flow to the pulmonary arteries in these neonates.^49,50 Although rare in neonates, hypercyanotic or tetralogy “spells” are characterized by increased rate and depth of respiration with increasing cyanosis; they can occur without warning and may be precipitated by feeding, crying, or defecation.⁵¹ Early detection and treatment can preserve cardiovascular and brain function by reducing symptoms caused by TOF (Table 2).⁴⁴

Tetralogy of Fallot requires surgical repair, sometimes as one full repair, generally during infancy, and occasionally as a staged approach with an initial palliative procedure.⁵² With tetralogy of Fallot there is a range of pulmonary outflow narrowing; this accounts for variability in presentation and postnatal management.⁴⁴ In cases of pulmonary atresia or severe pulmonary stenosis, PGE infusion is required to augment pulmonary blood flow via the ductus arteriosus.⁴⁹ In these cases, neonatal palliation with a systemic to pulmonary shunt or stenting of the PDA can be an initial surgical step, followed by complete surgical repair to close the VSD and surgically open the pulmonary outflow at about 6 months of age.^44,50 Depending on the degree of pulmonary valve stenosis, surgical interventions to open the pulmonary outflow tract may leave the neonate without a functional pulmonary valve. The infant could then require future procedures for valve replacements.⁵³

A full neonatal surgical repair can be performed in less severe cases of TOF.⁴⁴ Neonates with mild to moderate pulmonary stenosis may have sufficient pulmonary blood flow or “balanced” circulation, and may not need surgical repair for several months. During this preoperative period, infants are followed as outpatients with regular assessment of oxygen saturations and growth.

Pulmonary Atresia with Intact Ventricular Septum

Pulmonary atresia is a type of CHD with incomplete development of the pulmonary valve.⁵⁴ This defect is often referred to as “PA with an intact ventricular septum (PA/IVS)” to differentiate it from variants of TOF with PA, or PA with VSD. On average, 550 neonates are diagnosed with PA annually in the United States.²¹ In a normal heart the pulmonary valve controls the flow of deoxygenated blood from the RV to the lungs through the pulmonary arteries (Figure 5).⁵⁴ In PA/IVS, the pulmonary valve is closed or atretic, preventing the blood flow of deoxygenated blood to the lungs.²¹ Prenatally, the pulmonary arteries receive retrograde flow from the ductus arteriosus.⁵⁵ If ductal patency is not maintained postnatally, pulmonary blood flow will be disrupted, depriving the body of oxygenated blood and resulting in severe cyanosis in the neonate.⁵⁶ There are varying degrees of hypertrophy of the walls of the RV and underdevelopment or hypoplasia of its body and cavity.⁵⁷ The severity of these conditions depends on when the pulmonary valve became atretic during fetal development, the tricuspid valve size, and whether the tricuspid valve has regurgitation.⁵⁷ The RV and tricuspid valve will often become hypoplastic if blood cannot egress from the RV.⁵⁷ Furthermore, the RV’s muscle can form with connections or fistulas to the coronary arteries if there is inflow into the RV, but no ability for outflow (atretic pulmonary valve and no tricuspid regurgitation).⁸ This can result in the abnormal formation of the coronary arteries, or RV-dependent coronary circulation, which can lead to an extremely poor outcome for the neonate.⁸

FIGURE 5. Pulmonary atresia with intact ventricular septum.

Source: Centers for Disease Control and Prevention and National Center on Birth Defects and Developmental Disabilities. Pulmonary Atresia with Intact Ventricular Septum. https://www.cdc.gov/ncbddd/heartdefects/images/PulmonaryAtresia-intact-600px.jpg

Clinical Presentation and Assessment Findings.

The symptoms of PA/IVS in a newborn include cyanosis, shortness of breath, fatigue, and feeding difficulties.⁵⁶ Preoperatively, neonates with pulmonary atresia have blood oxygen saturation levels of 65–84 percent (Table 1).⁵⁸

Interventions and Nursing Implications.

Neonates with PA/IVS have deficient pulmonary blood flow. They are dependent on a patent ductus arteriosus for pulmonary blood flow. They become symptomatic with closure of the ductus and without intervention severe cyanosis will ensue.⁵⁵ Preoperative management aims to preserve appropriate oxygen saturation.⁵⁹ A PGE infusion is required as a first step to allow perfusion to the pulmonary circulation through the PDA; thus blood can become oxygenated in the lungs and sent to the systemic circulation.⁵⁵

Intervention for PA/IVS depends on the size of the tricuspid valve and RV, as well as the presence or absence of RV-to-coronary artery fistulae.⁵⁵ In certain cases the right side of the heart has appropriate size and function, thus allowing the neonate to have a curative pulmonary valvuloplasty performed in the cardiac catheterization laboratory.⁶⁰ In other cases, the neonate has a hypoplastic tricuspid valve and RV and undergoes a 3-stage surgical palliation for a single ventricle, similar to that described above for HLHS. The difference is that the first stage consists of a systemic to pulmonary artery shunt or a stent in the ductus arteriosus, followed by a bidirectional Glenn procedure, and later a Fontan procedure.⁵⁵ With other types of PA/IVS, an intermediate surgery is performed that includes a combination of a shunt followed by a bidirectional Glenn procedure and RVOT opening, a so-called “one and a half” ventricle repair.⁶¹ In severe forms of RV-dependent coronary circulation, the child is at risk for myocardial infarction from abnormal coronary artery perfusion, and a heart transplant may be necessary (Table 2).^62,63

NEURODEVELOPMENTAL OUTCOMES

Neonates requiring cardiac surgery within the first year of life are at higher risk for abnormalities of brain maturation as well as neurodevelopmental delays compared to healthy infants.^64-66 Some preoperative neonates with CHD can have motor deficits, such as increased or decreased tone, and a reduced ability to suck and feed.⁶⁷ Later as toddlers, children with CHD continue to show high rates of delay in cognition, language, vision, and motor functions, which have been related to head circumference and feeding status.⁶⁸ Therefore, early diagnosis of CHD in neonates will allow for more timely detection of neurodevelopmental delays, which can direct early interventions to reduce delays and improve long-term neurodevelopmental outcomes. Longitudinal surveillance and evaluation of neurodevelopmental outcomes in neonates with CHD are necessary to improve the quality of care and life of children with CHD.⁶⁹

DISCUSSION

A postnatal diagnosis usually occurs for neonates presenting with cyanosis, heart murmur, respiratory distress, or difficulty feeding. Neonates with CHD will be transported to a NICU or cardiothoracic or cardiovascular intensive care unit (CTICU or CVICU), depending on the institution.⁸ Initial stabilization with an infusion of PGE allows neonates with CHD to be safety transported to specialized heart centers and to allow preoperative recovery of end-organ functions to patients in shock.⁵ Neonates with PGE infusions undergoing interhospital transport have traditionally been intubated for that transport. Research has shown that intubation may not be necessary for transport of these infants.⁷⁰

Based on echocardiography and an established diagnosis, therapy is directed to ensure optimal cardiac output and regulate cyanosis while awaiting corrective or palliative surgery.⁷¹ Preoperative interventions to maintain pulmonary and systemic blood flow can potentially minimize neurologic injury.^11,69,72-75 Frequent, focused examination of the infant is an important and distinctive contribution that the nurse makes to the outcome of the patient.⁷⁶ Assessment of capillary refill time, skin temperature and color, pulses, edema, heart rate and rhythm, mental status, blood pressure, atrial pressures, and oxygen saturation occurs on a continuous basis.⁷⁶ A thorough cardiac examination should be performed using inspection, palpation, and auscultation (Table 2).⁷⁷

The most severe forms of neonatal CHD can require an emergency life-sustaining procedure in the neonatal period. This can be done by a minimally invasive approach, such as cardiac catheterization, to place a stent in the ductus arteriosus, open an atretic pulmonary valve via balloon pulmonary valvuloplasty, or open an atrial septum with balloon atrial septostomy^78-80 or with cardiac surgery—palliative, staged, or curative.

CONCLUSION

Four common types of CHD that require neonatal hospitalization are HLHS, D-TGA, TOF, and PA/IVS. Preoperative care for neonates with these types of complex CHD focuses on maintaining adequate cerebral and systemic circulation and oxygenation. Prostaglandin E, supplemental oxygen, or mechanical ventilation are typically used to facilitate circulation and oxygenation. Stabilizing neonates with CHD preoperatively will allow for safer surgical or catheterization-based interventions. Understanding the anatomy and physiology of these common types of CHD and the strategies for neonatal management will help to improve the care and outcomes of children with CHD.

Biographies

Nhu N. Tran, PhD, RN, is a nurse scientist at Children’s Hospital Los Angeles and an Assistant Professor of Clinical Pediatrics at the University of Southern California. She is certified as a critical care registered nurse in the Neonatal Intensive Care Unit and Clinical Research Professional. Her research aims to identify the mechanism of brain injury and developmental delay in vulnerable infants, to devise interventions that can improve their developmental outcomes.

Michelle Tran, MPH, is currently a PhD student in epidemiology at USC where she is studying cancer disparities among Asian immigrants. She was a previous Children’s Hospital Los Angeles intern, where she assisted in research examining neurological development in infants with congenital heart disease.

Ruth E. Lemus, BSN, RN, has been a nurse at Children’s Hospital of Los Angeles for over 17 years and has specialized in the care of pediatric patients with congenital heart defects. She currently works as a clinical research nurse and Society of Thoracic Surgeons congenital database manager. She has recently been named to The Society of Pediatric Cardiovascular Nurses (SPCN) Board in the role of Treasurer.

Jessica Woon is an undergraduate at the University of Southern California, currently studying Human Biology, with a double minor in Health Care Studies and Web Technologies and Applications. Jessica hopes to pursue a career in Pediatric medicine in the future.

Ryan Dang is an undergraduate at the University of California, Los Angeles, currently studying Physiological Sciences. Ryan’s goal is to go to medical school and pursue a career in Trauma Surgery.

Jeraldine Lopez, BA, is a research coordinator for the Division of Research on Children Youth and Family at Children’s Hospital Los Angeles (CHLA). She earned a Bachelor of Arts Degree in Psychology from California State University, Northridge (CSUN). Jeraldine hopes to pursue a career in pediatric nursing.

Jodie K. Votava-Smith, MD, is a pediatric and fetal cardiologist at Children’s Hospital Los Angeles (CHLA), where she is Associate Director of the Fetal Cardiology Program, and Assistant Professor of Pediatrics at the University of Southern California. Dr. Votava-Smith is actively involved in the detection and prenatal management of fetuses with congenital heart disease, which has provided her the unique opportunity to study the outcomes of fetuses with critical heart lesions and develop new strategies to improve both prenatal and postnatal management. Dr. Votava-Smith’s current research investigates cerebral blood flow, brain imaging, and neurodevelopmental outcomes in fetuses, infants, and children with congenital heart disease, with a goal to understand the origins of abnormal brain development and brain injury seen in these patients to optimize their clinical care and neurodevelopmental potential.