Peds BootCamp Notes
Overview of Congenital Heart Defects (CHD)
Congenital Heart Defects (CHD) refer to abnormalities in the structure of the heart or great vessels that are present at birth.
They are classified into two main categories: cyanotic defects and acyanotic defects.
1. Pathophysiology of Congenital Heart Defects
Definition: CHD involves abnormal development leading to alterations in blood flow within the heart. This can include shunted blood flow, obstructed flow, or abnormal mixing of different types of blood.
Common Characteristics:
More prevalent in children with chromosomal abnormalities such as Down syndrome and Marfan syndrome.
Blood flow alterations can lead to various complications.
2. Classification of Congenital Heart Defects
2.1. Cyanotic Defects
Characteristics: Cyanotic defects are more severe than acyanotic defects as they lead to poorly oxygenated blood being circulated.
Mechanism of Blood Flow:
Blood shunted from the right side (R) to the left side (L) of the heart, bypassing the lungs.
Mixing of oxygenated and deoxygenated blood.
Symptoms of Cyanosis:
Cyanosis: A bluish discoloration typically seen circumorally (around the mouth) and in extremities (hands and feet).
Triggered by increased oxygen demand such as during feeding or crying.
Polycythemia: This is a compensatory increase in red blood cell production to enhance oxygen delivery, which may also increase blood viscosity and lead to related complications.
Clinical Findings: Fatigue, dyspnea (shortness of breath), poor feeding, failure to thrive, and fingernail clubbing.
2.1.1. Management for Cyanotic Defects
Focus areas include:
Managing hypercyanotic spells.
Maintaining fluid balance and perfusion.
Managing Hypercyanotic Spells:
Immediate interventions should include comfort measures for the infant, positioning the knees to the chest (which increases blood flow to the lungs), and providing 100% oxygen.
Medications such as morphine (which promotes pulmonary vasodilation) and IV fluids may be administered as necessary.
Maintaining Fluid Balance:
Regular monitoring of intake and output, including daily weights and diaper weights to assess hydration.
Offer small, frequent feedings, being mindful that dehydration could increase stroke risk due to higher blood viscosity in polycythemia.
Use IV air filters in infants with right-to-left shunts to prevent air embolisms.
2.2. Types of Cyanotic Defects (Table 1)
Defects with Reduced Pulmonary Blood Flow:
Tetralogy of Fallot: Characterized by the following four defects:
Pulmonic stenosis (narrowing of the outflow tract from the right ventricle).
Right ventricular hypertrophy.
Ventricular septal defect (VSD).
Overriding aorta (the aorta straddles the ventricular septal defect).
Finding: Hypercyanotic spells are more frequent in children with Tetralogy of Fallot.
Treatment: Surgical repair should be performed within the first year of life.
Tricuspid Atresia: The tricuspid valve fails to develop, obstructing blood flow from the right atrium to the right ventricle, causing right-to-left shunting of blood via an atrial septal defect (ASD).
Defects with Mixed Blood Flow:
Transposition of the Great Arteries (TGA): Characterized by an abnormal positioning of the aorta and pulmonary arteries.
Treatment: Prostaglandin E1 is administered to keep the ductus arteriosus open to facilitate blood mixing and requires surgical repair soon after birth.
Truncus Arteriosus: Oxygenated and deoxygenated blood mix and exit from a single vessel, leading to oxygenation issues.
Total Anomalous Pulmonary Venous Return: Pulmonary veins return oxygenated blood to the right atrium instead of the left, leading to mixing of blood types.
Hypoplastic Left Heart Syndrome: The left ventricle is underdeveloped, resulting in right-to-left shunting through an ASD; oxygenated and deoxygenated blood mix.
3. Acyanotic Defects
Characteristics: These defects lead to impaired cardiac output and/or perfusion, typically resulting in heart murmurs or abnormal pulses, and can become severe, leading to heart failure.
3.1. Clinical Findings and Symptoms
Symptoms include:
Tachypnea (rapid breathing), tachycardia (rapid heart rate) as compensatory mechanisms.
Pulmonary hypertension (high blood pressure in the lungs) leading to dyspnea, fatigue, or grunting.
Fluid overload, presenting as sudden weight gain or peripheral edema.
Poor feeding and failure to thrive.
3.2. Nursing Care for Acyanotic Defects
Focus on:
Maintaining fluid balance.
Improving cardiac output.
Maintaining Fluid Balance:
Regular monitoring of intake and output, including daily weights.
Improving Cardiac Output:
Minimize energy expenditure by clustering care and swaddling.
Provide small, frequent feedings.
Administer heart failure medications as listed in Table 2 below.
3.3. Heart Failure Medications (Table 2)
Diuretics (e.g., Hydrochlorothiazide, Furosemide):
Mechanism: Facilitate diuresis, reducing preload and workload on the heart.
Monitoring: Essential to track fluid and electrolyte status.
Digoxin:
Mechanism: Increases contractility and cardiac output.
Considerations: Assess apical pulse for 1 minute before administration, holding if under 90-110 bpm in infants. Monitor potassium levels as hypokalemia can result in toxicity.
Angiotensin-Converting Enzyme Inhibitors (ACEIs) (e.g., Captopril, Enalapril):
Mechanism: Lower blood pressure, decreasing afterload and consequently the workload on the heart.
3.4 Types of Acyanotic Defects (Table 3)
Defects with Increased Pulmonary Blood Flow (Left-to-Right shunt)
Blood is shunted from the high-pressure left heart to the lower-pressure right heart, resulting in increased blood flow to the lungs and potential pulmonary hypertension.
Defects Include:
Septal Defects: Abnormal openings in the atria or ventricles (ASD, VSD, AVSD) lead to left-to-right shunting.
Findings: Characteristic systolic murmur.
Treatment: Surgical or nonsurgical (transcatheter) closure.
Patent Ductus Arteriosus (PDA): Failure of the ductus arteriosus to close postpartum leads to shunting.
Findings: Continuous machinery-like murmur with bounding pulses.
Treatment: Surgical closure or administration of indomethacin (NSAID for closure).
Obstructive Defects
A defect that obstructs blood flow increases the pressure before the obstruction and causes strain on the ventricles.
Types Include:
Aortic and Pulmonic Stenosis: Narrowing of the aortic or pulmonary valves obstructs forward blood flow.
Findings: Heart murmur.
Treatment: Balloon angioplasty to dilate narrow areas.
Coarctation of the Aorta (COA): Narrowing of the aorta; causes increased pressure proximal to the obstruction and decreased flow and pressure distally.
Findings: Marked difference in blood pressure and pulses between upper and lower extremities (bounding pulses above the obstruction; weak pulses below).
Treatment: Surgery, balloon angioplasty, or stenting may be required.
4. Postoperative Care
CHD is typically diagnosed with echocardiograms or cardiac catheterization. It is essential to delay catheterization if the infant has diaper rash.
Postoperative Management:
Monitor for signs of bleeding, assessing chest tube output closely.
Monitor for signs of decreased cardiac output, observing blood pressure and heart rate, and checking urine output.
Prevent infection by maintaining incision cleanliness and notifying healthcare providers of any signs of infection (fever, drainage).
Prophylactic antibiotics should be given before dental procedures to mitigate the risk of infective endocarditis.
References
Harding, M. M., Kwong, J., Hagler, D., & Reinisch, C. (Eds.). (2023). Lewis’s medical-surgical nursing: Assessment and management of clinical problems (12th ed.). Elsevier.
Hockenberry, M., Duffy, E.A., & Gibbs, K. (2024). Wong’s nursing care of infants and children (12th ed.). Elsevier.
Ignatavicius, D., Heimgartner, N., & Rebar, C. (Eds.). (2024). Medical-surgical nursing: Concepts for clinical judgment and collaborative care (11th ed.). Elsevier.
Keenan-Lindsay, L., Sams, C., & O’Connor, C. (2022). Perry’s maternal child nursing care in Canada (3rd ed.). Elsevier Health Sciences (US).
McKinney, E., Mau, K., Murray, S., James, S., Nelson, K., Ashwill, J., & Caroll, J. (2022). Maternal-child nursing (6th ed.). Elsevier Health Sciences.