cardiovascular

CARDIOVASCULAR SYSTEM IN PEDIATRICS

VARIATIONS IN PEDIATRIC ANATOMY AND PHYSIOLOGY

  • Structural and Functional Differences

    • Increased thickness of the ventricles, with left ventricle thicker than right.

    • High heart rate (HR) in infancy decreases over time due to increased efficiency of the heart.

    • Low blood pressure (BP) in infancy increases over time as the length of vessels increases.

    • Innocent murmurs and physiologic splitting of heart sounds observed in children.

    • Cardiac Output (CO) is calculated using the formula:
      CO = HR imes SV

    • where HR = Heart Rate and SV = Stroke Volume.

CIRCULATORY CHANGES FROM GESTATION TO BIRTH

  • Key structures involved in fetal circulation:

    • Foramen Ovale:

    • An opening between the atria allowing blood to bypass the right ventricle and lungs.

    • Ductus Arteriosus:

    • An opening between the pulmonary artery and aorta, allowing blood to flow directly into the systemic circulation.

    • Ductus Venosus:

    • A vessel that shunts blood flow from the umbilical vein directly to the inferior vena cava.

Fetal and Newborn Circulation

  • Fetal Circulation Diagram:

    • Ductus arteriosus, foramen ovale, and ductus venosus are highlighted.

  • Newborn Circulation:

    • Ligamentum arteriosus after ductus arteriosus closure; multiple veins and arteries involved in the transition.

POSSIBLE DIAGNOSTIC PROCEDURES

  • Cardiac Catheterization:

    • A procedure that is diagnostic, interventional, and electrophysiologic.

    • A radiopaque catheter is threaded into the heart.

    • Functions of cardiac catheterization:

    • Can take pictures of the heart structure.

    • Biopsy heart tissue.

    • Measure blood pressures and oxygen saturation (O2 sats) in each chamber.

    • Monitor cardiac output (CO).

Pre-Operative Considerations

  • Thorough health history taking.

  • Assess for infections and allergies (iodine sensitivity).

  • Locate pedal pulses prior to the procedure.

  • Patient is to be NPO (nothing by mouth) prior to the procedure.

Post-Operative Management

  • Cardiovascular checks.

  • Monitor for dressing integrity and assess for bleeding or infection at the catheter site.

  • Patient needs to lie flat for 4-8 hours post-procedure.

  • Observe for arrhythmias and thrombus formation.

  • Monitor intake and output, encouraging oral fluid intake.

CONGENITAL HEART DISEASE (CHD)

  • Etiological Factors:

    • Stimuli such as viruses, environmental factors, genetic factors, and prenatal exposures contribute to the development of CHD.

  • Pathophysiological Responses:

    • Can lead to heart failure or hypoxemia.

    • Four general categories:

    1. Decreased Pulmonary Blood Flow

    2. Increased Pulmonary Blood Flow

    3. Obstruction to Blood Flow

    4. Mixed Blood Flow

Decreased Pulmonary Blood Flow

  • Characteristics:

    • Obstruction of flow to the lungs leads to right to left shunting, resulting in cyanosis and polycythemia.

  • Examples include:

    • Tetralogy of Fallot:

    • Comprised of:

      • Pulmonary stenosis

      • Ventricular septal defect (VSD)

      • Overriding aorta

      • Right ventricular hypertrophy

    • Tricuspid Atresia:

    • Complete closure of the tricuspid valve between the right atrium and right ventricle.

Assessment Criteria for Tetralogy of Fallot

  • Symptoms include:

    • Hypercyanotic episodes

    • Hypoxemia

    • Dyspnea

    • Agitation

    • Progressive cyanosis

    • Clubbing or polycythemia

    • Loud harsh systolic murmur and positioning such as squatting to relieve symptoms.

Tricuspid Atresia Characteristics

  • Associated with an atrial septal defect (ASD) or patent foramen ovale.

  • Assessment findings:

    • Cyanosis

    • Dyspnea

    • Tachycardia

    • Difficulty with feeding, cool clammy skin, and clubbing.

Disorders with Increased Pulmonary Blood Flow

  • Characteristics:

    • Obstruction of blood flow to the body, leading to left to right shunting, which can result in heart failure and pulmonary hypertension.

  • Examples:

    • Atrial Septal Defect (ASD):

    • A passage between the right and left atria.

    • Assessment:

      • Poor feeding or growth, increased caloric needs, presence of crackles, increased HR, susceptibility to respiratory infections, and loud harsh murmur.

Ventricular Septal Defect (VSD)

  • Characterized by a passage between right and left ventricles.

  • Nursing assessment findings:

    • Symptoms include tiredness, poor feeding and growth, edema, diaphoresis, dyspnea, and increased heart rate accompanied by a loud harsh murmur at the sternal border.

Patent Ductus Arteriosus (PDA)

  • Definition:

    • Persistence of the ductus arteriosus connecting the pulmonary artery and aorta.

    • Symptoms include respiratory infections, crackles, fatigue, poor growth, increased heart rate, bounding pulses, a wide pulse pressure, and a continuous machine-like murmur.

Obstructive Disorders

  • Definition:

    • Conditions characterized by narrowing of a major vessel, restricting blood flow, and causing increased pressure and workload of the heart.

  • Examples include:

    • Coarctation of the Aorta:

    • Defined as narrowing of the aorta causing obstruction of blood flow from the ventricle.

    • Assessment noted includes leg pain during activity, headache, elevated BP and bounding pulse in upper body, while low BP and thready pulses are observed in lower extremities, stating a 20-point difference.

    • Murmur may be present with dizziness, fainting, or nosebleeds.

Mixed Defects

  • Definition:

    • Conditions causing mixing of well and poorly oxygenated blood leading to decreased oxygen saturation (SaO2) and decreased cardiac output, ultimately resulting in heart failure.

  • Examples include:

    • Transposition of the Great Vessels:

    • There is no connection between pulmonary and systemic circulations, frequently associated with ASD or VSD.

    • Assessment findings:

      • Cyanosis during feeding or crying, dyspnea, absent murmurs, tachypnea, and tachycardia.

Truncus Arteriosus

  • Definition:

    • A condition where one single vessel arises from both ventricles supplying blood to both systemic and pulmonary circulations, often accompanied by a ventricular septal defect (VSD).

    • Assessment:

    • Presenting signs and symptoms include heart failure, lethargy, fatigue, poor feeding, and variable cyanosis, alongside a murmur.

Hypoplastic Left Heart Syndrome

  • Definition:

    • Characterized by the underdevelopment of the left side of the heart, with significantly small mitral and aortic valves, frequently presenting with an ASD and patent foramen ovale.

    • Assessment findings include mild cyanosis, heart failure, lethargy, and cold extremities, with PDA closure leading to exacerbation of cyanosis.

NURSING MANAGEMENT FOR CONGENITAL HEART DISEASE

  • Goals include:

    • Improving oxygenation: elevate head of bed, provide oxygen, suctioning, and humidification.

    • Promoting adequate nutrition:

    • Ensure increased caloric intake, maintain fluid and electrolyte balance, serve small frequent meals, and encourage hydration.

    • Preventing infections: Manage to reduce heart workload through Fowlers positioning, bed rest, and cluster care.

    • Assisting patients and families: Education and continuous support, monitoring daily weight, and administering medications as prescribed.

ACQUIRED CARDIOVASCULAR DISORDERS

  • Definition of Heart Failure:

    • Results from impaired contraction and decreased ejection, leading to dilation/hypertrophy of chambers, increased myocardial oxygen consumption, and limited stretch.

    • Results in clinical signs indicating the heart’s inability to pump effectively, providing inadequate blood and oxygen to meet metabolic demands.

Nursing Assessment for Heart Failure

  • Health history:

    • Key symptoms include babies consuming small volumes before needing rest, sweating while feeding, and preference for upright positioning for comfort.

  • Physical examination findings:

    • Note rapid weight gain or lack thereof, tachycardia, tachypnea or dyspnea, cyanosis, cool extremities, diaphoresis, peripheral edema, gallop rhythm, and the presence of crackles indicating fluid overload.

Acute Rheumatic Fever

  • Etiology:

    • Inflammatory disease that is a delayed sequela (2-6 weeks) of group A strep infection (strep throat).

  • Response includes inflammation of cardiac muscle, joints, and central nervous system.

Management of Acute Rheumatic Fever

  • Assessment and management involve:

    • Detailed health history to assess upper respiratory infections, management of activity intolerance, symptomatic treatments, managing painful swollen joints, bed rest for muscle weakness, and addressing involuntary movements (chorea), irritability, fever, and associated symptoms.

Hyperlipidemia

  • Etiological Factors:

    • Conditions such as genetics, obesity, lack of exercise, diabetes, kidney disease, hypothyroidism contribute to the response of excess lipids in blood.

    • Diagnosis: Total cholesterol >170 mg/dL.

  • Management strategies include maintaining dietary history, promoting low-fat diets rich in whole grains, fruits, and vegetables, in addition to at least 60 minutes of aerobic exercise daily.

Kawasaki Disease

  • Etiology:

    • Unknown etiology that responds with acute systemic vasculitis, leading to inflammation and edema of blood vessels throughout the body.

  • Assessment criteria:

    • Symptoms include fever, strawberry tongue, edema of hands and feet, desquamation in various areas, enlarged lymph nodes, irritability, and non-specific cardiologic findings.

  • Management includes hydration with IV fluids, oral hygiene, cool cloths for skin, and use of aspirin and gamma globulin as prescribed.