Pediatric Cardiovascular

Pediatric Cardiovascular Notes

Fetal Development

• Nutrient and Waste Exchange
  • Occurs through the placenta.
  • Umbilical Vein: Carries oxygenated blood from the placenta through the ductus venosus to the inferior vena cava.
  • A small amount of blood enters the right ventricle; most blood flows into the left atrium through the foramen ovale.
  • The majority of blood entering the right ventricle bypasses the lungs via the ductus arteriosus, flowing directly to the descending aorta.
  • Blood reaching the lungs supplies lung cells only.
  • Most blood passes from the right atrium to the left atrium, then to the left ventricle for systemic distribution.
  • Descending Aorta: Carries blood to umbilical arteries, returning to the placenta for waste exchange and nutrient pickup.

Fetal Development (Cont.)

• Intrauterine Heart Rate: Normal range is 120-160 beats per minute (bpm).
• Oxygen Saturation: Approximately 80%.
• Placental Pressure Gradient: Facilitates rapid diffusion of carbon dioxide from fetal blood to maternal blood.

Fetal Hemoglobin

• Composed of 2 alpha and 2 gamma chains.
• Exhibits greater affinity for oxygen than adult hemoglobin.
• Newborn Hemoglobin: Approximately 17.1 g/dL compared to adult normal of 12 g/dL.
• Newborn Hematocrit: About 53% versus adult normal of 45%.
• Changes in hemoglobin composition begin before birth and continue until about 6 months after birth.

After Birth Changes

• Lungs Expand: Major change post-birth.
• Increased oxygen levels induce pulmonary vasodilation.
• Pulmonary pressures drop while systemic pressures rise.
• Closure of the foramen ovale occurs soon after birth.
• The ductus arteriosus begins to close as oxygen concentrations rise in blood.
• Clamping of the umbilical cord ceases blood flow through the ductus venosus, leading to its closure.

Risk Factors for Pediatric Cardiovascular Problems

• Family History: Family history of heart disease increases risk.
• Intrauterine Factors: Exposure to known teratogens, infectious diseases, and prenatal nutrition/radiation/drugs/toxins.
• Lifestyle Factors: Hypertension, obesity, and lack of exercise.
• These risk factors can lead to increased chances of cardiovascular disorders during childhood.

Physical Assessment

• Growth Measurements: Measure height and weight, aiming for a relaxed child.
• Assessment for Cyanosis:
  • Inspect buccal membranes and lips for centrally located cyanosis; persistent central cyanosis post-birth may indicate cardiopulmonary dysfunction.
  • Cyanosis can worsen with crying (suggestive of cardiac dysfunction) or may decrease with crying (indicative of pulmonary dysfunction).
• General Assessment:
  • Check for clubbing of fingers, capillary refill, complexion variations (ruddy), lethargy, and increased respiratory rates.
  • Observe for prominence of the heart movement on the left thoracic side.
• Heart Rate Assessment:
  • Tachycardia defined as > 160 bpm in infants and > 100 bpm in 3-year-olds.

Murmur Assessment

• Murmur Classification: Describe according to:
  • Position in Cardiac Cycle: early systolic, mid-systolic, late diastolic, etc.
  • Duration, Quality, Pitch, and Intensity: Intensity graded I (softest) to VI (loudest).
  • Location: Site of the murmur in the heart.
  • Presence of a Thrill: Indicates turbulent blood flow.
  • Response to Exercise or Position Changes: Determines whether the murmur is innocent or pathologic.

Innocent vs Pathologic Murmurs

• Innocent Murmur: No clinical significance and considered a normal variation of heart sounds; requires no follow-up or activity restrictions.
• Pathologic Murmur: Indicates heart disease or congenital defects and warrants further investigation.

Locations of Murmurs

Diagnostic Techniques

Laboratory Studies Assessment

• History Taking: Obtain a comprehensive account of complaints and a medication list.
• Pre-test Instructions: No food or fluid intake restrictions; demonstrate procedures on dolls for understanding.
• Post-Procedure Care: Observe the site for venipuncture related complications.

Diagnostic Testing

• Blood Chemistry Tests: Including sodium, potassium, and other relevant parameters.
• Hematology Evaluation: Hemoglobin, hematocrit, platelets, and Erythrocyte Sedimentation Rate (ESR).

Arterial Blood Gas Assessment

• Purpose: Assesses acid-base balance and oxygenation status.
• Pre-Test Requirements: Allen’s test if using the radial artery; may use lidocaine for local anesthesia.
• Components & Normal Values:
  • pCO2: partial pressure of CO₂; normal values are different for newborns and children.
  • pO2: partial pressure of O₂; normal values differ for age groups.
  • Normal Ranges (Adult):
  • pH: 7.35-7.45
  • pCO2: 35-45 mmHg
  • HCO₃: 22-26 mEq/L
  • pO₂: 80-100 mmHg
  • O₂ Sat: 95-100%

Cardiac Catheterization

• Purpose: Detects cardiac abnormalities, evaluates cardiac output, and provides imaging of heart structures.
  • Pre-Operative Requirements: Chest X-ray, EKG, blood type exams, electrolyte assessments.
  • Procedure Details: Patient stays still during sedation, catheter insertion via a small vein or artery.
  • Post-Procedure Monitoring: Focus on site bleeding, thrombophlebitis, or signs of infection.

Electrocardiogram (EKG or ECG)

• Basic Info: Records electrical activity using electrodes, analyzing heart rhythms.
• Normal Waveforms: P wave, QRS complex, PR interval, ST segment, T wave, with specific time interval ranges for children and adults.

Echocardiogram

• Description: Echocardiography utilizes high-frequency sound waves to create cardiac images.
• Applications: Evaluates heart structure movement, size, wall thickness, and blood flow velocity.
• No Radiation Risk: Safe imaging technique utilized frequently in pediatric assessments.

Fluoroscopy

• Usage: Radioangiocardiography allows tracing of a radioactive substance throughout the heart and blood vessels.
• Patient Care: Requires lying still, hydration post-procedure, monitoring vital signs.

Nursing Assessment

Subjective Assessment

• Family History: Inquiry into familial cardiac issues.
• Past and Current History: Collection of relevant individual health history.

Objective Assessment

• Inspection: Observe nutritional state, color, chest deformities, unusual pulsations, and respiratory excursion.
• Auscultation: Heart sounds and respiratory rates must be carefully examined.

Cardiovascular Problems

Congenital Heart Disease

• Definition: Primary anatomic abnormalities present at birth; can lead to congestive heart failure (CHF) and hypoxemia.
• Acquired Cardiac Disorders: Develop postnatally due to environmental factors, infections, or autoimmune responses.

Classification of Congenital Heart Disease

• Cyanotic: Right-to-left blood shunting causing body desaturation.
• Acyanotic: Left-to-right shunting, body organs receive oxygenated blood.

Specific Conditions

• Atrial Septal Defect: Abnormal opening allows blood flow from left atrium to right atrium; can close spontaneously or require intervention. Monitor for complications like endocarditis.
• Ventricular Septal Defect (VSD): Abnormal opening allows left-to-right shunt; most cases close spontaneously but may require surgical closure based on size.
• Patent Ductus Arteriosus: Fetal ductus does not close after birth, allowing blood to flow from the aorta to pulmonary artery; management includes medical or surgical intervention.
• Obstructive Blood Flow Conditions: Such as aortic stenosis and coarctation, increase pressure and workload on the heart.
• Tetralogy of Fallot: Contains four defects leading to right-to-left shunt, requiring surgical repair.
• Transposition of the Great Arteries: Aorta and pulmonary artery switch positions, requiring immediate surgical intervention.
• Truncus Arteriosus: Single great vessel supplies both systemic and pulmonary blood flows; often requires surgical intervention.

Congestive Heart Failure Symptoms & Management

• Signs: Tachypnea, diaphoresis, poor weight gain, and generalized edema.
• Management: Limit activity, provide oxygen therapy, medications (diuretics, inotropes), and provide education on diet and medication compliance.

Kawasaki Disease

• Definition: Serious condition characterized by inflammation, typically affecting children; can lead to significant cardiovascular effects.
• Management: IV immunoglobulin therapy and high-dose aspirin; monitor for coronary complications.

Rheumatic Fever

• Description: Inflammatory disorder following streptococcal infection; can result in rheumatic heart disease.
• Management: Through antibiotic therapy, anti-inflammatories, and long-term follow-up to prevent recurrence.

Endocarditis

• Description: Infection leading to inflammation of the heart valves; common in patients with pre-existing heart conditions.
• Management: Hospitalization for IV antibiotics, prophylactic measures are important to prevent recurrence during procedures.