Emergency Presentation of Heart Disease

Abstract

Pediatric patients with congenital and acquired heart disease may present to the emergency department (ED) with acute life-threatening decompensation. These children often present with high acuity and in shock, with cyanosis, or with respiratory distress. In this chapter we review common ED presentations of pediatric heart disease and their chronology, pathophysiology, management strategies, and common diagnostic clues/pitfalls that clinicians may face when treating these complex patients.

Introduction

Congenital heart defects (CHD) are the most common congenital malformations with an estimated prevalence of 6–8 per 1000 live births [1]. Advances in fetal ultrasound and echocardiography have improved the prenatal detection of CHD. In addition, screening for critical congenital heart disease (CCHD) was added to the US Recommended Uniform Screening Panel in 2011. Since that time, CCHD screening with pulse oximetry has become nearly universal for newborns born in the United States [2]. Approximately 25% of neonates with CCHD will not be detected by pulse oximetry alone, and many children will not be diagnosed until after discharge from the hospital. Reasons for undiagnosed CHD at birth include the lack of prenatal diagnosis due to no or poor prenatal care, standard ultrasonography missing CHD, postnatal detection failure through pulse oximetry, or home birth. Most cardiac emergencies due to CHD in undiagnosed children most often present in neonates and infants less than 1 year of age. When previously undiagnosed children present with life-threatening cardiac emergencies, it is often the physicians in the ED (including those who predominantly care for adults) or the primary care providers in an office setting who will first see the patient. Also, with improved surgical outcomes of complex CHD, there are more adults than children with CHD in developed countries. Emergency presentations of CHD often masquerade as other common entities delaying diagnosis and prompt institution of lifesaving therapy. Pediatric cardiac emergencies may result from anatomic abnormalities (congenital or acquired) or electrophysiological dysfunction. The latter is discussed in Chap. 8 .

Symptomatology of Cardiac Emergencies in Children

There are three major symptom complexes that children with previously undiagnosed heart disease present with life-threatening emergencies. These are (1) respiratory distress, (2) shock, and (3) cyanosis. The clinical manifestations and pathogenesis of these symptom complexes and responsible underlying pathophysiologic states are outlined in Table 1.1. Of these symptom complexes, respiratory distress and shock are fraught with many diagnostic pitfalls and may be mistaken for other commonly encountered entities in children such as asthma, bronchiolitis, pneumonia (respiratory distress), dehydration, and sepsis (shock) (Table 1.2). The physician must look for diagnostic clues whenever presented with such scenarios.

Table 1.1 Emergency presentation of heart disease in children

Table 1.2 Cardiogenic shock : diagnostic pitfalls

Chronology of Presentation of Heart Disease in Children

Neonatal and infantile cardiopulmonary adaptation has a profound influence on the likelihood of a specific congenital heart lesion presenting at a given age. Before birth, the fetal circulation is in parallel circuits. The airless lungs have suprasystemic vascular resistance accepting only 10% of cardiac output. A large portion of venous return to the right side of the heart is shunted across the foramen ovale (FO) and ductus arteriosus (DA) to the left side of the heart. The systemic circulation including the placenta accepts 90% of total cardiac output. The fetus tolerates complex congenital heart lesions as the FO and DA allow the right side of the heart to take over the function of the left side of the heart and vice versa.

Early Neonatal Period (1–7 Days)

Soon after birth, with initiation of air-breathing and oxygen-induced pulmonary vasodilation, the pulmonary vascular resistance (PVR) falls to 50% of systemic vascular resistance (SVR) which rises as placental circulation ceases to exist. Also, the FO and DA initially close functionally and then subsequently close anatomically. The circulation changes to being in series as the right ventricular stroke volume approaches that of the left ventricle with very little if any blood being shunted across the FO or DA. In this phase of early neonatal hemodynamic adaptation , several groups of congenital lesions are prone to manifest. These are:

Systemic arteriovenous fistula : The increasing systemic venous return flowing into the lung allows greater shunting across arteriovenous (AV) fistulae resulting in high-output congestive heart failure. The two places to look for AV fistula in a young infant with high-output failure are a) aneurysm of the vein of Galen and b) liver. It is important to auscultate for a bruit on the head and on the liver when dealing with such situations.

Left-sided obstructive lesions : Because of the functional closure of DA, the right ventricle cannot push blood into the descending aorta to maintain systemic perfusion. Lesions such as hypoplastic left heart syndrome, critical aortic stenosis, and interrupted aortic arch are likely to present in 1–7 days of life with systemic hypoperfusion, cardiogenic shock, and lactic acidosis. This hypoperfusion predominately manifests in the child as a gray and listless appearance rather than overt central cyanosis.

Right-sided obstructive heart lesions : Pulmonary blood flow can be maintained at a sufficient level for adequate oxygenation as long as the left ventricle can pump enough blood across the DA into the pulmonary artery. As the DA begins to close, an increasing amount of systemic venous return is shunted into the systemic arterial circulation. Lesions such as tricuspid atresia, hypoplastic right heart syndrome, and pulmonary atresia present in the early neonatal period with central cyanosis as the DA begins to close. Some cyanotic heart diseases such as tetralogy of Fallot may not manifest until a few weeks after birth as long as the right ventricular outflow tract (RVOT) is not too severely obstructed and allows reasonable amount of pulmonary blood flow. These patients are sometimes missed during the initial neonatal pulse oximetry screening. Cyanosis develops when RVOT obstruction worsens resulting in increased shunting across the ventricular septal defect.

Independent circuits : Transposition of the great vessels (TGV), where the aorta and pulmonary artery are transposed, presents soon after birth when functional closure of FO and DA prevent mixing of blood in the two circuits resulting in cyanosis.

Pulmonary venous obstruction : As pulmonary arterial flow increases after birth so does the pulmonary venous flow back to the left atrium. Lesions associated with obstruction to pulmonary venous flow such as total anomalous pulmonary venous return (TAPVR) and cor triatriatum will present in the early neonatal period with increasing pulmonary venous hydrostatic pressure and pulmonary edema resulting in respiratory distress and cyanosis. If the pulmonary venous return is less severely obstructed, such lesions may not manifest until later in life.

Early Infancy (6 Weeks–3 Months)

In the first 6 weeks to 3 months of life, the pulmonary vascular resistance continues to fall as the pulmonary arterial tunica media muscle continues to involute. By 3 months of age, the PVR declines to about 15% of SVR, a relationship that is maintained into adulthood. Since the tunica media muscle is mainly deposited in the last trimester of pregnancy, prematurely born infants have a more rapid fall in PVR compared to infants born after full term. The following lesions are more likely to become symptomatic at the age of 6 weeks to 3 months:

Left-to-right shunt : Ventricular septal defect (VSD), atrial septal defect (ASD), and patent ductus arteriosus (PDA) allow increasing pulmonary blood flow with decreasing pulmonary vascular resistance. The result is an increase in pulmonary blood flow (Qp) compared to systemic blood flow (Qs), hyperdynamic circulation, and congestive heart failure. Clinical manifestations include respiratory distress, tachycardia, bounding pulses, and eventually cardiac decompensation. If left untreated, left-to-right shunts result in hypertrophy of the medial musculature and intimal changes which lead to a rise in PVR and pulmonary hypertension limiting the amount of shunt. Without surgical intervention such children are at risk of developing suprasystemic PVR and Eisenmenger complex and right-to-left shunting.

Anomalous origin of left coronary artery from pulmonary artery (ALCAPA) : While children are born with ALCAPA, the lesion does not manifest itself at birth. Even though the left coronary artery is carrying deoxygenated blood, myocardial oxygen consumption is not compromised as long as the pulmonary artery pressure (PAP) remains sufficiently elevated. The myocardial oxygen consumption is more dependent on coronary perfusion pressure compared to coronary oxygen content since the heart is one of the most efficient extractors of oxygen. It is when PVR, and therefore the PAP, falls below a critical level, the anomalous left coronary artery fails to perfuse the myocardium with sufficient blood flow to maintain its oxygen demands. The manifestations are those of episodic screaming (angina), feeding difficulty (effort intolerance), and overt cardiogenic shock (myocardial infarction).

Any Age

Certain conditions are not dependent on postnatal cardiovascular adaptation. They can present at any age. Infection (myocarditis, pericarditis, sepsis) and cardiomyopathies should be considered at any age when cardiac dysfunction is suspected (Table 1.3).

Table 1.3 Age-specific lesions and most common ED presentations

Practical Considerations for Initial Care Providers

Ductal-dependent lesions should be a consideration in all neonates presenting in shock and/or cyanosis in the neonatal period. Alprostadil (PGE1) infusion may be lifesaving if instituted even prior to an established diagnosis. FO-dependent lesions (TGV, obstructed TAPVR) may need balloon atrial septostomy. All patients with suspected CCHD should be promptly transferred to tertiary care centers.

Oxygen administration , which is a common intervention for life-threatening pediatric emergencies, may have deleterious consequences in certain cardiac lesions. Elevated PaO₂ results in constriction of DA and pulmonary vasodilation. In left-sided obstructive lesions of the heart, constriction of DA would result in worsening of systemic hypoperfusion, shock, and lactic acidosis. Pulmonary vasodilation in single ventricle physiology (e.g., Norwood surgery for hypoplastic left heart syndrome) may result in a greater proportion of cardiac output going to the lungs (Qp) at the expense of the rest of the body (Qs). Also, in left-to-right shunts, pulmonary overcirculation resulting from vasodilation may worsen pulmonary edema. Oxygen administration in such situations must be carefully monitored to maintain SaO₂ around 75–80% in single ventricle physiology and around 90% in left-to-right shunts.

Administration of albuterol in a child whose respiratory symptoms are secondary to myocardial dysfunction will lead to increased oxygen demands on an already compromised heart. Excessive fluid resuscitation for decreased cardiac output and apparent dehydration in a situation with a failing heart will have similar adverse consequences (Table 1.4). Early identification of cardiac etiology as the underlying mechanism of life-threatening manifestations is of utmost importance.

Table 1.4 Risks of commonly employed treatment strategies

Important Historical Findings in Infants with Heart Disease

Unlike older children and adults, infants and young children are unable to articulate their symptoms. The clinician needs to seek from the caretaker certain historical findings that may act as surrogates for symptoms that older children may complain about (Table 1.5). Tachypnea, rapid or congested breathing, and wheezing are suggestive of pulmonary edema from congestive heart failure. Feeding difficulty and failure to thrive could be manifestations of effort intolerance and increased work of breathing. Excessive sweating may result from increased sympathetic activity and obvious chest “pounding” could be a result of hyperdynamic circulation. Episodes of screaming may signify angina from coronary ischemia.

Table 1.5 Important historical findings of heart disease in infants

Case Presentation 1

A 4-day-old, full-term neonate is brought to the ED by his parents for poor feeding and lethargy. His vital signs are as follows: temperature 36.2 °C, heart rate (HR) 192 beats per minute, respiratory rate (RR) 63 breaths per minute, and blood pressure (BP) 62/37 mmHg with oxygen saturation (SpO2) of 92% on room air. On examination, the baby appears lethargic with cool extremities and capillary refill time of 4 s. He has nasal flaring with intercostal retractions. Liver edge is palpable 3 cm below the right costal margin. The saturations improve to 97% on 100% oxygen. Repeat vital signs after initiation of oxygen administration show a HR of 212 beats per minute, RR of 75 breaths per minute, and a right upper extremity BP of 54/23 mmHg. A chest radiograph demonstrates pulmonary edema and cardiomegaly (Fig. 1.1). An initial arterial blood gas (ABG) demonstrates pH 7.15, PCO₂ 28 mmHg, PaO₂ 94 mmHg, bicarbonate 10 mEq/L, and lactate 12 mmol/L.

Fig. 1.1

Chest radiograph showing cardiomegaly and early pulmonary edema

The neonate in this vignette has signs of shock, severe metabolic acidosis, and marked hyperlactatemia. The etiology of shock in an infant needs to be determined and lifesaving measures employed rapidly. Cardiogenic shock should be suspected in all such infants in addition to hypovolemia and sepsis. In this infant presenting with shock in the first week of life, there are no historical findings to account for hypovolemia, hypotension, and poor perfusion. Therefore treatment for an underlying ductal-dependent cardiac disease is imperative. Obstructive lesions of the left side of the heart such as HLHS, critical aortic stenosis, coarctation of the aorta, and interrupted aortic arch are at the top of the list of differential diagnosis. The infant may appear relatively normal at birth as long as the DA remains open, and the postobstructive systemic circulation is maintained by the right ventricle through the pulmonary artery and DA. Symptoms appear when closure of the DA leads to systemic hypoperfusion. These children are not cyanotic but rather appear ashen gray because of hypoperfusion and increased peripheral oxygen extraction. In order to maintain ductal patency and establish systemic blood flow, alprostadil infusion must be started. Since alprostadil is a systemic vasodilator, judicious intravenous fluid expansion may be necessary to maintain normal blood pressure for age.

The use of oxygen in a child with shock due to a left-sided obstructive lesion can be of particular harm as oxygen itself is a potent DA constrictor which may further limit blood flow through a compromised DA. Ductal patency is a major factor that determines the difference between survival and death in a child dependent on the DA for systemic blood flow.

Unlike the infant in the vignette, a child with right-sided obstructive lesions (pulmonary atresia, tricuspid atresia,) or independent circuits (TGA) will present with central cyanosis and often has PaO₂ ~40 and oxygen saturations ~75%. In cyanotic infants, the hyperoxia test may be utilized as a clinical tool to differentiate between pulmonary and cardiac disease. The test is based on the principle that 100% oxygen will increase alveolar PO₂, leading to an increase in systemic arterial PO₂ in the absence of a fixed cardiac shunt. In cyanotic congenital heart disease, little or no rise in PaO₂ would be expected after breathing 100% O₂. An arterial blood gas analysis done both before and after the administration of 100% O₂ demonstrating an increase in PaO₂ to more than 100 mmHg would suggest a respiratory disease, while an increase of PaO₂ of less than 80 mmHg would require evaluation for cyanotic CHD. Thus, persistent hypoxia refractory to 100% oxygen supply would indicate cyanotic CHD rather than a primary pulmonary disease. It should be noted that the hyperoxia test should be utilized only in cyanotic infants to differentiate cyanosis from pulmonary vs. cardiac etiology. It should not be used in infants who are in shock and therefore appear gray but have SpO₂ above 90%. These patients should be suspected of ductal-dependent left-sided obstructive lesion in whom 100% oxygen administration could be detrimental.

The most important first step in managing a neonate presenting within the first week of life with either shock or cyanosis necessitates that the ED physician considers a ductal-dependent cardiac lesion and initiates the administration of an alprostadil drip to improve patency of the DA.

Case Presentation 2

A 3-month-old, full-term male presents to the ED due to tachypnea and poor feeding for the last 12 h. His vital signs are temperature 37 °C, HR 170 beats per minute, RR 50 breaths per minute, BP 78/50 mmHg, and oxygen saturation 94% on room air. On examination he is fussy and showing signs of respiratory distress. Extremities are cool with prolonged capillary refill time. He has grunting, retractions, and wheezing bilaterally. Liver edge is palpable at 4 cm below the costal margin. His cardiac examination is significant for a gallop. Capillary blood gas reveals pH 7.28, PCO₂ 20 mmHg, sodium bicarbonate 11 mEq/L, and lactate 5.8 mmol/L. Chest radiograph shows cardiomegaly and left lung atelectasis (Fig. 1.2). The EKG is obtained (Fig. 1.3 ). What is the most likely diagnosis? What are the risks of albuterol, 100% oxygen, and fluid boluses?

Fig. 1.2

Chest radiograph showing marked cardiomegaly and left lung atelectasis

Fig. 1.3

Electrocardiogram showing deep Q waves in left-sided chest leads

The infant in this vignette is presenting with signs of uncompensated heart failure and systemic hypoperfusion. Infants 1 month to 6 months of age with undiagnosed congenital heart disease usually present to the ED with signs of heart failure due to decreasing pulmonary vascular resistance (PVR) . In lesions with large intracardiac left-to-right shunts (large ventricular septal defects, atrioventricular canal defects, large patent DA), the continued decline in PVR results in increasing pulmonary blood flow. This increased pulmonary blood flow may cause the child to present with volume overload and signs and symptoms of congestive heart failure (poor feeding, tachypnea, grunting, retractions, cardiac wheezing, tachycardia, hepatomegaly, gallop, metabolic acidosis with respiratory alkalosis, and cardiomegaly on chest radiography). These infants often show evidence of hyperdynamic circulation with bounding pulses and increased pulse pressure.

The infant in this vignette exhibits cardiogenic shock with peripheral vasoconstriction and decreased pulse pressure. EKG shows myocardial infarction evidenced by deep Q waves in left-sided leads. This clinical picture is pathognomonic of ALCAPA which is typically unmasked during the early infancy period. As PVR and PAP decrease, the coronary perfusion pressure is compromised resulting in myocardial ischemia and infarction. Symptoms of a failing left ventricle and congestive heart failure progressing to shock develop around 2–4 months of age. The diagnostic clues include the signs of shock and the deep Q waves on left-sided leads on EKG.

An infant who presents with heart failure may be misdiagnosed as having viral bronchiolitis, bacterial pneumonia, or asthma. These infants may be treated with fluid boluses due to tachycardia or concern for sepsis. This may worsen the clinical status of a child in shock from congestive heart failure. Similar to Case Presentation 1, a careful history and examination to differentiate the etiology of shock must be undertaken with attention to tachypnea, gallop rhythm, jugular venous distension (JVD), hepatomegaly, and weak pulses. This assessment could prevent the inappropriate excessive administration of fluids to a child in CHF. The use of oxygen in an infant with CHF can be of particular harm as oxygen itself is a pulmonary vasodilator and may worsen left-to-right shunting and further increase pulmonary overcirculation and worsen pulmonary edema. Finally, administration of albuterol with resultant tachycardia in a child whose respiratory symptoms are secondary to myocardial dysfunction will lead to increased oxygen demands on an already compromised heart.

Acute management of infants with CHF includes optimizing hemodynamic status, decreasing oxygen consumption, maintaining optimal preload, decreasing afterload, and improving contractility. Decreasing oxygen consumption is achieved by taking away the work of breathing by sedation and mechanical ventilation, achieving atrioventricular synchrony, and avoiding β-agonists bronchodilators and other medications that may cause tachycardia. Maintaining optimal preload may require an isotonic intravenous fluid bolus. This requires frequent assessments of the clinical response to fluid. Excessive fluid administration will not be well tolerated and may worsen pulmonary edema. Improving contractility with the addition of inotropic support may be necessary.

Case Presentation 3

A 16-year-old female presents to the ED with difficulty breathing, emesis, and progressive listlessness. She has had a previous ED visit for progressive wheezing and shortness of breath 7 days ago. She was given an albuterol inhaler and dexamethasone. Despite the use of his inhaler every 6 h, her shortness of breath and wheezing worsened. Her temperature is 38.2 °C, HR 118 beats per minute, RR 23 breaths per minute, BP 102/70 mmHg, and SpO₂ 92% on RA. On examination, she has mild respiratory distress and is taking shallow, quick breaths. Her lung fields are notable for diffuse crackles and wheezing. Her cardiac examination reveals tachycardia with a gallop rhythm and capillary refill of 3 s. Her rhythm strip suggests sinus tachycardia. She is given an albuterol treatment and fluid bolus of 20 mL/kg of normal saline. During the breathing treatment and fluid bolus, she suddenly develops hypotension and worsening respiratory distress. Repeat vital signs are as follows: HR 145 beats per minute, RR 45 breaths per minute, and BP 72/42 mmHg. She is somnolent, with rapid breathing and diffuse wheezing. Cardiac exam reveals tachycardia with poor peripheral pulses. She has hepatomegaly 4 cm below costal margin. CXR reveals pulmonary infiltrates and cardiomegaly (Fig. 1.4.) What are the diagnostic approach and management strategies in this patient?

Fig. 1.4

Chest radiograph showing marked cardiomegaly and pulmonary edema

This child is presenting with signs of acute decompensated heart failure . Similar to the infant in the earlier vignette, this child has signs and symptoms of heart failure including difficulty breathing, wheezing, tachycardia, gallop, hepatomegaly, and cardiomegaly. The differential diagnosis includes dilated cardiomyopathy (due to genetic causes, chronic hypertension, etc.), large pericardial effusion, and myocarditis. This child was previously healthy but had a preceding viral illness 7 days prior to the ED visit suggesting myocarditis. Myocarditis may occur at any age although studies indicate that infants and teenagers are more commonly affected. Common pitfalls include misdiagnosis as asthma or bacterial pneumonia and initiation of steroids or β-agonist bronchodilator therapy which will be harmful. Immediate management is centered around optimizing cardiac output (contractility, preload, and afterload) and transfer to a tertiary care pediatric cardiac center.

ED Management

The goals of ED management are to stabilize the airway, obtain vascular access, and support the circulation and in neonates and infants to establish and maintain patency of the ductus arteriosus. Age and physical examination findings will be the most helpful clues toward diagnosis in the initial assessment period (Table 1.3). Alprostadil infusion should be considered in infants <1 month who present in shock or cyanosis where ductal-dependent lesion is strongly suspected based on history and clinical findings. While echocardiography is necessary to make the diagnosis, awaiting echocardiography to initiate therapy may result in wasting valuable time to open the ductus and may contribute to mortality. Side effects of alprostadil include hypotension from systemic vasodilation, apnea, and fever. Blood pressure should be closely monitored, and hypotension should be treated with judicious intravascular fluid expansion. Most of these infants require prophylactic intubation and mechanical ventilation during transport.

Neonates and infants with shock, respiratory distress, or profound cyanosis may require positive pressure ventilation. Unlike older children and adults, noninvasive positive pressure (NIPPV) will rarely be an option. More likely the patient will need a definitive airway via endotracheal intubation. Prior to intubation ED physicians should prepare for further deterioration due to cardiopulmonary interactions after intubation, the effects of intubation medications, and supplemental oxygen on the pulmonary vascular bed. Pulmonary arterial reactivity and risk for pulmonary hypertensive episodes in response to medications and the unavoidable peri-intubation trauma are important considerations.

Positive pressure ventilation (PPV) has advantages and disadvantages due to cardiopulmonary interactions. Disadvantages include peri-intubation trauma, decrease in venous return leading to decreased RV preload, and increase in RV afterload. The advantages of PPV include decrease in LV afterload, limitation of left-to-right shunting, improvement in pulmonary edema, and reduction in work of breathing. The goal of PPV is to minimize the risks and maximize the benefits.

Careful selection of intubation medications is important. Many sedatives decrease systemic vascular resistance (SVR) and are myocardial depressants which contribute to hypotension, reduced aortic diastolic pressure, and poor cardiac output. Yet, sedation is needed to minimize the risk of pulmonary hypertensive crisis and for safe intubation. Intubation agents should be chosen thoughtfully and are discussed in detail in Chap. 7. In addition, supplemental oxygen should be considered similar to a drug that can have desirable effects (pulmonary vasodilation in infants at risk for pulmonary hypertension) and undesirable effects in other situations (constriction of the DA, pulmonary vasodilation, and worsening of left-to-right shunting).

Summary

ED presentations of pediatric heart disease are age and lesion specific. Children with cardiac emergencies present with respiratory distress, shock, or cyanosis. The likelihood of a given disease entity depends on the age at presentation. Tachycardia, sweating, poor feeding, cyanosis, hepatomegaly, wheezing, and cardiomegaly may be important diagnostic clues. Common pitfalls are misdiagnosis as other respiratory disorders commonly encountered in children such as asthma, bronchiolitis, and pneumonia and conditions such as sepsis and dehydration. Routinely employed ED therapeutic agents such as oxygen, bronchodilators, fluid administration, etc. may be potentially harmful in this patient population, and a high index of suspicion is necessary to manage these complex patients in the acute setting.

Clinical Pearls

• Neonates with ductal-dependent lesions typically present early within the first weeks to a month of life.

• Initiation of alprostadil (PGE1) should not be delayed in a neonate who presents in shock or with cyanosis.

• Infants with large left-to-right shunts and ALCAPA present to the ED with acute heart failure as pulmonary vascular resistance drops between 1 and 6 months of age.

• Myocarditis and arrhythmias may occur at any age.

• Goals of management include stabilizing the airway, initiating alprostadil therapy promptly when indicated, optimizing preload, decreasing afterload, and improving contractility.

• Acute management of heart failure is based on optimizing preload, reducing systemic vascular resistance, and reducing myocardial oxygen consumption.

Board Exam Questions

• 1. A 3-week-old male born at full term presents to the ED with tachypnea. He was well until yesterday when he stopped feeding. On physical examination he is irritable and tachypneic with a respiratory rate of 60 breaths per minute with a HR of 170 beats per minute. He is afebrile and right upper extremity blood pressure is 70/50 mmHg. Extremities are cool with delayed capillary refill and femoral pulses are difficult to palpate. Oxygen saturations are 94% on room air. What is the most important next step in managing this patient?

  • (A) Intubation and mechanical ventilation

  • (B) Systemic antibiotics

  • (C) Albuterol treatment with administration of 100% oxygen

  • (D) Initiate alprostadil (PGE-1) infusion

• 2. The neonate from question 1 has an echocardiogram performed in the ED showing severely depressed LV function and no evidence of a patent ductus arteriosus. The next most appropriate treatment for this child is to initiate:

  • (A) Calcium chloride infusion

  • (B) Vasopressin infusion

  • (C) Continuous albuterol inhalation

  • (D) Epinephrine infusion and reassess end organ perfusion

• 3. The neonate from question 1 most likely has which one of the following diagnoses?

  • (A) Total anomalous venous return (TAPVR)

  • (B) Anomalous coronary artery from the left pulmonary artery (ALCAPA)

  • (C) Myocarditis

  • (D) Critical coarctation of the aorta

• 4. A 4-month-old with known unrepaired atrioventricular septal defect presents to the ED with poor feeding and respiratory distress. On arrival to her bedside, you see a small infant with tachypnea, retractions, and nasal flaring. Vital signs show a T 37 °C, HR 160 beats per minute, RR 60 breaths per minute, BP 80/40 mmHg, and SpO₂ 92% on high-flow nasal cannula at 8 L per minute with 70% FiO₂. On respiratory examination, the liver is 4 cm below the costal margin, and a systolic murmur over the precordium and bilateral wheezes are heard. The nurse asks you if FiO₂ should be raised because of the low SpO₂. Which of the following is the best response?

  • (A) Increase the FiO₂ to 80%

  • (B) Increase the FiO₂ to 100% and prepare for intubation

  • (C) Increase in FiO₂ will not help because of right-to-left shunting

  • (D) Titrate the FiO ₂ downwards as long as SpO ₂ remains > 90%