3.2 Congenital Heart Defects

BCEN CPEN Certified Pediatric Emergency Nurse Exam

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1 Chapter 1: Exam Overview, Triage Process & Initial Emergency Assessment

1.1 CPEN Exam Logistics, Blueprint & Certification Overview 1.2 Pediatric Triage Systems & Acuity Categorization 1.3 Pediatric Assessment Triangle (PAT) & Initial Impression 1.4 Primary & Secondary Pediatric Emergency Assessment 1.5 Age-Specific Vital Signs, Developmental Considerations & Pain Scales

2 Chapter 2: Pediatric Respiratory Emergencies

2.1 Upper Airway Obstruction 2.2 Lower Airway Emergencies 2.3 Respiratory Distress vs. Respiratory Failure & Airway Management

3 Chapter 3: Pediatric Cardiovascular Emergencies

3.1 Pediatric Dysrhythmias & ECG Analysis 3.2 Congenital Heart Defects 3.3 Acquired Heart Disease & Heart Failure

4 Chapter 4: Pediatric Neurological Emergencies

4.1 Pediatric Seizures, Status Epilepticus & Febrile Seizures 4.2 Altered Mental Status, Increased ICP & Head Trauma 4.3 Pediatric Central Nervous System Infections

5 Chapter 5: Pediatric Gastrointestinal & Genitourinary Emergencies

5.1 Pediatric GI Surgical Emergencies 5.2 Pediatric Dehydration, Gastroenteritis & Fluid Resuscitation Protocols 5.3 Pediatric GU & Renal Emergencies

6 Chapter 6: Pediatric Endocrine, Metabolic & Hematologic/Oncologic Emergencies

6.1 Diabetic Ketoacidosis (DKA) & Hypoglycemia in Pediatric Emergency Patients 6.2 Electrolyte Imbalances & Inborn Errors of Metabolism 6.3 Sickle Cell Disease Crisis & Pediatric Oncologic Emergencies

7 Chapter 7: Pediatric Musculoskeletal, Integumentary & ENT/Ophthalmic Emergencies

7.1 Pediatric Musculoskeletal Injuries & Fractures 7.2 Pediatric Dermatologic Emergencies & Rashes 7.3 Pediatric ENT & Ocular Emergencies

8 Chapter 8: Pediatric Trauma Emergencies

8.1 Pediatric Trauma Resuscitation & Anatomical Vulnerabilities 8.2 Head, Spinal & Thoracic Trauma in Children 8.3 Abdominal, Pelvic & Extremity Trauma in Pediatric Patients

9 Chapter 9: Child Maltreatment, Toxicology & Behavioral Emergencies

9.1 Child Abuse, Neglect, Non-Accidental Trauma & Mandatory Reporting 9.2 Pediatric Toxicology, Toxidromes & Emergency Antidotes 9.3 Pediatric Behavioral & Mental Health Crisis Management

10 Chapter 10: Pediatric Multi-System Emergencies, Shock & Thermal Injuries

10.1 Pediatric Shock Recognition & Classification 10.2 Pediatric Sepsis, Septic Shock & Multiple Organ Dysfunction Syndrome 10.3 Pediatric Anaphylaxis & Severe Allergic Reactions 10.4 Submersion Injuries, Drowning & Thermal/Burn Emergencies

11 Chapter 11: Professional Practice, Legal, Ethical & Safety Standards

11.1 Legal & Ethical Considerations 11.2 Patient Safety, Medication Error Prevention & Weight-Based Dosing 11.3 Family-Centered Care, Communication & Disaster/Surge Preparedness

3.2 Congenital Heart Defects

Key Takeaways Explain This Topic AI

Congenital heart defects are classified as acyanotic (left-to-right shunting/obstruction causing pulmonary over-circulation or heart failure) or cyanotic (right-to-left shunting causing systemic arterial hypoxemia).

Coarctation of the Aorta presents with upper extremity hypertension and bounding radial pulses contrasted with lower extremity hypotension and weak or absent femoral pulses.

Transposition of the Great Arteries (TGA) creates parallel non-communicating circulatory loops causing severe cyanosis that fails to improve with 100% hyperoxia testing.

Prostaglandin E1 (Alprostadil) is life-saving in duct-dependent cardiac lesions by maintaining ductal patency, but requires continuous monitoring for drug-induced apnea.

Hypercyanotic 'Tet' spells in Tetralogy of Fallot require immediate placement of the infant in a knee-to-chest position to increase Systemic Vascular Resistance (SVR) and reduce right-to-left shunting.

Last updated: July 2026

Congenital Heart Defects & Emergency Management

Congenital Heart Defects (CHDs) represent the most common category of major birth defects, occurring in approximately 8 per 1,000 live births. In the emergency department, pediatric nurses encounter infants with undiagnosed structural heart disease presenting in acute circulatory collapse as the fetal ductus arteriosus closes, as well as older children with known CHD presenting in acute decompensation. Understanding structural anatomy, shunting dynamics, and hypercyanotic spell management is essential for CPEN success.

Classification of Congenital Heart Defects

Structural cardiac anomalies are classified functionally based on blood flow patterns and systemic oxygenation: ┌─────────────────────────────────────┐

│ Congenital Heart Defects │
└──────────────────┬──────────────────┘
│
┌─────────────────────────┴─────────────────────────┐
▼ ▼
┌───────────────────────────┐ ┌───────────────────────────┐
│ Acyanotic Defects │ │ Cyanotic Defects │
│ (Left-to-Right Shunting) │ │ (Right-to-Left Shunting) │
└─────────────┬─────────────┘ └─────────────┬─────────────┘
│ │
┌──────────┴──────────┐ ┌──────────┴──────────┐
▼ ▼ ▼ ▼
┌───────────────┐ ┌───────────────┐ ┌───────────────┐ ┌───────────────┐
│ Increased Pulm│ │ Obstructive │ │ Decreased Pulm│ │ Mixed Blood │
│ Blood Flow │ │ Lesions │ │ Blood Flow │ │ Flow │
│ (VSD, ASD, │ │ (Coarctation, │ │ (Tetralogy of │ │ (Transposition│
│ PDA) │ │ Aortic Steno) │ │ Fallot, TA) │ │ of Great Art)│
└───────────────┘ └───────────────┘ └───────────────┘ └───────────────┘
Acyanotic Defects (Left-to-Right Shunts & Obstructions)

Oxygenated blood from the left side of the heart is shunted back into the right side and pulmonary circulation. Oxygen saturation remains normal (>95%), but pulmonary blood flow is volume-overloaded.

Clinical Presentation : Tachypnea, intercostal retractions, poor feeding, diaphoresis during feeding, failure to thrive, hepatomegaly, and pulmonary congestion.

Long-Term Risk : Untreated left-to-right shunting causes chronic pulmonary hypertension, eventually reversing the shunt to right-to-left ( Eisenmenger syndrome ), producing irreversible cyanosis.

Cyanotic Defects (Right-to-Left Shunts & Mixed Lesions)

Deoxygenated systemic venous blood bypasses the lungs and enters systemic arterial circulation directly, causing persistent arterial hypoxemia ( SpO2 70–85% ).

Clinical Presentation : Central cyanosis (mucous membranes, trunk), polycythemia (elevated hematocrit to compensate for chronic hypoxia), digital clubbing, and metabolic acidosis.

Hyperoxia Test : Administering 100% oxygen fails to significantly increase arterial oxygen tension (PaO2 remains <150 mmHg), confirming a right-to-left cardiac shunt rather than primary pulmonary parenchymal disease.

Major Structural Defects & Clinical Profiles

Defect Name Anatomical Pathology Shunt / Flow Key Diagnostic Findings Primary Emergency Management

Ventricular Septal Defect (VSD) Hole in ventricular septum Left-to-Right Harsh, holosystolic murmur at lower left sternal border; signs of CHF Diuretics (furosemide), ACE inhibitors, digoxin; surgical repair

Coarctation of Aorta (CoA) Discrete narrowing of thoracic aorta near ductus arteriosus Obstructive Upper extremity hypertension with bounding radial pulses ; lower extremity hypotension with weak/absent femoral pulses Prostaglandin E1 (Alprostadil) infusion to maintain ductal patency; avoid high-dose oxygen

Transposition of Great Arteries (TGA) Aorta arises from RV; Pulmonary Artery arises from LV Parallel Circuits Severe cyanosis within hours of birth; unresponsive to hyperoxia test; egg-on-a-string chest X-ray Prostaglandin E1 (Alprostadil) ; urgent balloon atrial septostomy (Rashkind procedure)

Tetralogy of Fallot (ToF) VSD, RVOT stenosis, Overriding Aorta, RV Hypertrophy Right-to-Left Loud systolic ejection murmur; boot-shaped heart on X-ray; hypercyanotic "Tet" spells Knee-to-chest position, 100% O2, morphine, IV fluid bolus, phenylephrine

Duct-Dependent Cardiac Lesions & Prostaglandin E1

Certain neonatal CHD structural anomalies rely on an open Ductus Arteriosus to maintain either systemic blood flow (duct-dependent systemic flow: Coarctation of Aorta, Hypoplastic Left Heart Syndrome) or pulmonary blood flow (duct-dependent pulmonary flow: Pulmonary Atresia, severe TGA).

As the ductus arteriosus naturally closes within the first 24 to 72 hours of life, these neonates present in severe cardiogenic shock, profound cyanosis, metabolic acidosis, and collapse.

Prostaglandin E1 (Alprostadil) Administration

Mechanism : Keeps the ductus arteriosus patent or reopens a recently closed ductus to re-establish life-sustaining perfusion.

Dosing : Initial IV/IO infusion rate of 0.05 to 0.1 mcg/kg/min . Once ductal patency is achieved, titrate down to the lowest effective maintenance dose (0.01–0.02 mcg/kg/min).

Adverse Effects & Nursing Vigilance :

Apnea : Occurs in up to 10–12% of neonates receiving PGE1. Elective endotracheal intubation equipment must be immediately available at the bedside prior to initiating infusion .

Fever & Vasodilation : Cutaneous flushing, severe hypotension, and hyperthermia are common; manage hypotension with volume boluses.

Hypercyanotic "Tet" Spells Management

Hypercyanotic spells ("Tet" spells) occur in children with Tetralogy of Fallot . They are acute paroxysms of severe cyanosis, hyperpnea, and agitation caused by a sudden increase in Right Ventricular Outflow Tract (RVOT) infundibular spasm or a drop in Systemic Vascular Resistance (SVR). This causes a dramatic surge in right-to-left shunting across the VSD, sending deoxygenated blood into systemic circulation.

Emergency Nursing Intervention Sequence Step 1: Knee-to-Chest Position ➔ Step 2: 100% Oxygen & Comfort ➔ Step 3: Morphine Sulfate IV

│
Step 6: Phenylephrine IV ◄─── Step 5: Sodium Bicarbonate IV ◄─── Step 4: IV Fluid Bolus (10-20 mL/kg)

Place Infant in Knee-to-Chest Position (or have older child squat): First immediate action . Squatting or flexing knees to chest compresses the femoral arteries, dramatically increasing Systemic Vascular Resistance (SVR). Higher SVR forces blood out of the right ventricle into the high-resistance pulmonary artery rather than shunting across the VSD into the aorta.

Administer 100% Supplemental Oxygen : Use a non-rebreather mask. Oxygen is a potent pulmonary vasodilator that lowers pulmonary vascular resistance (PVR) while treating arterial hypoxemia.

Provide Calm, Comforting Environment : Agitation increases endogenous catecholamines, worsening RVOT infundibular spasm. Minimize painful procedures and hold the child.

Administer Morphine Sulfate : Dosage 0.1 mg/kg IV/IM/SC . Morphine suppresses the central respiratory drive, reduces anxiety, and directly relaxes the infundibular cardiac muscle spasm.

Administer Isotonic IV Fluid Bolus : Administer 10 to 20 mL/kg normal saline . Volume expansion increases right ventricular preload and filling pressure, improving blood flow across the stenotic pulmonary valve.

Administer Sodium Bicarbonate : Dosage 1 to 2 mEq/kg IV . Treats systemic metabolic acidosis resulting from severe hypoxia.

Administer Phenylephrine : Dosage 0.005 to 0.02 mg/kg IV . Phenylephrine is a pure alpha-1 adrenergic agonist that increases SVR if the spell is refractory to position and morphine.