The Child With Cardiovascular Dysfunction Study Notes

Pediatric Cardiovascular Assessment

• History and Parental History:
  • Documenting all parental concerns regarding the child's health.
  • Reviewing the mother’s health history and experiences during pregnancy.
  • Conducting a thorough family history to identify genetic or hereditary cardiovascular trends.
• Inspection (Physical Observation):
  • Nutritional State: Assessing for growth delays or failure to thrive.
  • Color: Observing for cyanosis, pallor, or mottling.
  • Chest Deformities: Identifying abnormalities in the structure of the thoracic cage.
  • Unusual Pulsations: Looking for visible pulsations in the neck or chest.
  • Respiratory Excursion: Observing the ease and depth of breathing.
  • Digital Clubbing: Checking for thickening and flattening of the tips of the fingers and toes, common in chronic hypoxia.
• Palpation and Percussion:
  • Chest: Feeling for thrills or heaves.
  • Abdomen: Assessing for hepatomegaly or ascites.
  • Peripheral Pulses: Evaluating strength and symmetry in upper and lower extremities.
• Auscultation:
  • Monitoring heart rate and rhythm.
  • Measuring Blood Pressure in both arms and at least one leg to identify discrepancies.
  • Assessing the character and quality of heart sounds (S1, S2, and any presence of S3, S4, or murmurs).

Diagnostic Evaluation and Cardiac Catheterization

• Standard Diagnostic Tools:
  • Chest X-Ray
  • ECG (Electrocardiogram)
  • CBC (Complete Blood Count)
  • Echocardiogram
  • Arterial Blood Gas (ABG)
  • Cardiac Catheterization
• Cardiac Catheterization Overview:
  • Used for diagnostic purposes, interventional treatments, and electrophysiology studies.
  • In pediatric patients, right-sided catheterization is more common because it is safer and existing structural defects often allow the catheter to access the left side of the heart.
• Pre-procedural Nursing Care:
  • Conduct a full nursing assessment.
  • Maintain NPO (nothing by mouth) status for $4-6$ hours; clarify which morning medications should be administered.
  • Ensure IV fluids are prepared or running as ordered.
  • Provide developmentally appropriate psychological preparation to the child and family.
  • Coordinate sedation as required.
• Post-procedural Nursing Care:
  • Observe for complications including changes in color and level of consciousness.
  • Monitor vital signs and respiratory status frequently.
  • Distal Extremities: Pulses distal to the insertion site can be weaker for the first few hours but must be monitored closely.
  • Check dressing for signs of bleeding or hematoma.
  • Monitor fluid intake (IV and PO).
  • Monitor for hypoglycemia.
• Home Care/Discharge following Catheterization:
  • Keep the pressure dressing in place for $24$ hours.
  • No tub baths for $48$ hours.
  • The child should rest the first night, then may resume normal activities.
  • Teach parents the signs and symptoms of infection (redness, swelling, drainage, fever).

Developmental Differences in Cardiovascular Structure and Function

• Heart Size: In neonates, the right and left ventricles are equal in size.
• Less Compliance: Infancy is characterized by less developed and less organized muscle fibers in the heart, resulting in limited functional capacity and less compliance compared to adult hearts.
• Oxygen Saturation: Normal saturation levels are expected to be $95-100\%$.
• Anatomy: Infants and small children have very thin chest walls with minimal subcutaneous fat and muscle, making pulsations and heart sounds more prominent.

Fetal Circulation and Shunts

• Circulatory Differences:
  • The liver and lungs are largely bypassed in the fetus because oxygenation and filtration are managed by the mother.
  • The goal of fetal circulation is to ensure the maximum concentration of oxygenated blood reaches vital organs.
• Key Fetal Shunts:
  • Ductus Arteriosus: Bypasses the lungs by connecting the pulmonary artery to the aorta.
  • Foramen Ovale: Bypasses the lungs by allowing blood to flow from the right atrium to the left atrium.
  • Ductus Venosus: Bypasses the liver.
• Closure at Birth: Shunts close shortly after birth in response to:
  • Decreased maternal hormone Prostaglandin E.
  • Increased oxygen ($O_2$) saturations.
  • Shifts in pressure within the heart chambers.

General Clinical Findings for Cardiac Defects

• Infant Presentation: Dyspnea, feeding difficulty, failure to thrive, stridor, or choking spells.
• Vitals: Resting heart rate over $200$ beats per minute; respiratory rate approximately $60$ breaths per minute.
• Infections: Recurrent respiratory tract infections.
• Physical Signs: Cyanosis, digital clubbing, heart murmurs, excessive perspiration, and signs of heart failure.
• Older Child Presentation: Poor physical development, delayed milestones, decreased exercise tolerance, and compensatory behaviors like squatting or the knee-chest position.

Congestive Heart Failure (CHF) in Children

• Etiology: Most frequently occurs secondary to congenital heart defects that cause structural abnormalities, resulting in an increased volume load or increased pressure load on the ventricles.
• Pathophysiology (Sympathetic Nervous System Stimulation):
  • Stimulation of cholinergic fibers leading to increased rate and force of contraction.
  • Increased vascular tone and peripheral vasoconstriction.
  • Decreased blood flow to kidneys, inducing production of renin, aldosterone, and ADH.
  • Results in sodium ($Na$) and water ($H_2O$) retention and increased blood volume (increased preload).
  • Leads to systemic and pulmonary venous engorgement and increased afterload.
• Pulmonary Venous Congestion Manifestations: Tachypnea, wheezing, crackles, retractions, cough, dyspnea on exertion, grunting, nasal flaring, cyanosis, feeding difficulties, irritability, and fatigue with play.
• Systemic Venous Congestion Manifestations: Hepatomegaly, ascites, edema, weight gain, and neck vein distention.
• Impaired Myocardial Function: Tachycardia, weak peripheral pulses, hypotension, gallop rhythm, extended capillary refill, pallor, cool extremities, oliguria, fatigue, restlessness, enlarged heart, and sweating.
• High Metabolic Rate: Failure to thrive, slow weight gain, and perspiration (especially on the scalp).

Therapeutic Management of CHF

• Improve Cardiac Function: Utilization of digitalis and ACE inhibitors.
• Remove Accumulated Fluid and Sodium: Administration of diuretics such as Furosemide (Lasix).
• Decrease Cardiac Demands: Promoting rest and reducing the work of breathing.
• Improve Tissue Oxygenation: Providing supplemental oxygen and reducing oxygen consumption.

Pharmacological Management: Digitalis (Digoxin)

• Administration Rules:
  • Give at regular intervals.
  • Administer $1$ hour before or $2$ hours after meals.
  • Apical Heart Rate Check (1 Full Minute): Hold dose if heart rate is $< 90-110$ in infants/young children or $< 70$ in older children.
  • Do not mix with food or fluid.
  • Give behind the teeth or brush teeth after administration to prevent staining/damage.
  • Missed Doses: If $< 4$ hours late, give the dose. If $> 4$ hours late, withhold. If two doses are missed, notify the practitioner.
  • Vomiting: If the child vomits, do not repeat the dose.
  • Potassium ($K^+$): Check potassium levels prior to administration; hold if levels are low (hypokalemia increases risk of toxicity).
• Digoxin Toxicity Signs: Nausea, vomiting, bradycardia, anorexia, and neurologic/visual disturbances.
• Digitalis Toxicity Treatment:
  • Monitor closely for dysrhythmias (hyperkalemia may occur).
  • Digibind (Digoxin immune Fab fragments): Administered to bind digoxin; it is then excreted by the kidneys. Watch for rapidly dropping potassium levels after administration.

Nursing Considerations for the Child with CHF

• Activity Intolerance: Promote rest, group nursing activities, prevent crying, provide short intervals of play, and maintain a neutral thermal environment.
• Altered Nutrition:
  • Smaller, more frequent feedings (every $3$ hours).
  • Feeding should last no longer than $30$ minutes; remaining formula should be given via Nasogastric (NG) tube.
  • Use formula with increased calories per ounce.
  • Use a soft preemie nipple with a moderately large opening to reduce the effort of sucking.
  • Position the child semi-erect and burp frequently.
• Ineffective Breathing Pattern: Assess respiratory effort and saturations; position for maximum chest expansion; use humidified oxygen during stressful periods.
• Fluid Volume Excess: Maintain accurate Intake and Output (I&O); weigh daily at the same time, on the same scale, in the same clothes; provide good skin care; change positions frequently.

Acyanotic Heart Defects (Increased Pulmonary Blood Flow)

• Pathophysiology: Systemic pressure is greater than pulmonary pressure, resulting in a left-to-right shunt. This increases blood volume on the right side of the heart and leads to CHF symptoms.
• Atrial Septal Defect (ASD):
  • Defect in the septum between the right and left atria (often a patent foramen ovale).
  • Symptoms: Asymptomatic or murmur; risk for CHF, dysrhythmias, and emboli later in life.
  • Treatment: Surgical dacron patch or interventional septal occluder.
• Ventricular Septal Defect (VSD):
  • Incomplete formation of the septum between ventricles (ranges from pinpoint to total absence).
  • Symptoms: Moderate to severe CHF, cyanosis, characteristic murmur, Right Ventricular Hypertrophy, failure to thrive, and recurrent infections.
  • Treatment: Pulmonary artery banding, surgical patch repair, or septal occluder.
• Patent Ductus Arteriosus (PDA):
  • Failure of fetal ductus arteriosus to close, shunting blood from the aorta to the pulmonary artery.
  • Symptoms: "Machine-like" murmur, possible CHF.
  • Treatment: Indomethacin ($Prostaglandin\,E$ inhibitor), interventional coil, or surgical clip (VATS).

Obstructive Lesions

• Coarctation of the Aorta:
  • Narrowing near the ductus arteriosus.
  • Presentation: Increased pressure proximal (head/upper extremities) and decreased pressure distal (body/lower extremities).
  • Treatment: $Prostaglandin\,E$ to maintain PDA, balloon angioplasty, or surgery.
• Aortic Stenosis:
  • Narrowing of the aortic valve obstructing left ventricular outflow.
  • Clinical Note: Resulting low cardiac output and myocardial ischemia can cause sudden death. This is the only defect where activity is strictly restricted (e.g., quiet play, using elevators).
  • Treatment: Balloon dilation or aortic valvotomy/replacement.
• Pulmonic Stenosis:
  • Narrowing at the entrance to the pulmonary artery; "Pulmonary Atresia" describes total fusion with no blood flow to the lungs.
  • Treatment: Balloon angioplasty or surgery.

Cyanotic Heart Defects (Decreased Pulmonary Blood Flow & Mixed)

• Pathophysiology: Pressure is greater on the pulmonic side, causing a right-to-left shunt. Mixed oxygenated and deoxygenated blood enters systemic circulation, causing hypoxia.
• Physiological Adaptations: Cyanosis, polycythemia (increased RBCs), digital clubbing, and altered ABGs.
• Tetralogy of Fallot (TOF):
  • Combination of four defects: VSD, Pulmonic Stenosis, Overriding Aorta, and Right Ventricular Hypertrophy.
  • Symptoms: Murmur with thrill, polycythemia, and hypoxic "Tet spells."
  • Treatment: Blalock-Taussig shunt, VSD repair, and pulmonary valvotomy.
• Tricuspid Atresia:
  • Absence of the tricuspid valve; no communication between RA and RV.
  • Management: $Prostaglandin\,E$ to keep the foramen ovale open until surgery.
• Transposition of the Great Vessels:
  • Aorta arises from the RV and Pulmonary Artery from the LV. No communication between circulations without a separate defect.
  • Treatment: Arterial switch procedure within the first few weeks of life.
• Truncus Arteriosus:
  • A single large vessel fails to divide and empties both ventricles.
• Hypoplastic Left Heart Syndrome (HLHS):
  • Underdevelopment of the left side (aortic/mitral atresia, small LV).
  • Treatment: Norwood procedure, Fontan procedure, or cardiac transplant.

Emergency Management: Hypercyanotic "Tet" Spells

• Employed when a child with TOF becomes acutely cyanotic and distressed.
• Protocol:
  1. Employ a calm, comforting approach.
  2. Place the child in the Knee-Chest position (increases systemic vascular resistance).
  3. Administer $100\%$ oxygen via face mask.
  4. Administer Morphine (to reduce infundibular spasms).
  5. Initiate IV fluid replacement and volume expansion if needed.

Postoperative Complications and Discharge Planning

• Surgical Complications: CHF, dysrhythmias, cardiac tamponade, atelectasis, pneumothorax, pulmonary edema, pleural effusions, cerebral edema/brain damage, and hemorrhage/anemia.
• Discharge Education:
  • Wound care for incisions.
  • Medication administration training.
  • Bacterial Endocarditis Prophylaxis: Informing parents about the need for antibiotics before dental or invasive procedures.
  • Stressing immunizations, including RSV prophylaxis if $< 2$ years old.

Questions & Discussion

• Q: A $7$-month-old with suspected CHD returned from cardiac cath $20$ minutes ago. She is becoming restless and fussy. Mother is concerned. What is the nurse's priority action?
  • A: Evaluate the procedure site, extremities, and vital signs immediately to check for bleeding or complications.
• Q: If a child wears diapers, how can the catheterization site be protected from contamination?
  • A: Cover the dressing with plastic film and seal the edges with tape to prevent urine/feces from reaching the wound.
• Q: Calculate the Lanoxin dose for Nancy ($3.6\,kg$). Order: $0.018\,mg$ PO BID. Concentration: $50\,\mu g/ml$.
  • A: Step 1: Convert $0.018\,mg$ to $\mu g \rightarrow 18\,\mu g$. Step 2: $\frac{18\,\mu g}{50\,\mu g/ml} = 0.36\,ml$. The nurse instructs the parents to give $0.36\,ml$ orally twice a day.
• Q: What intervention is expected for a $6$-week-old in CHF with VSD who is feeding poorly and irritable?
  • A: Place an N/G feeding tube and institute feedings to meet maintenance fluid requirements to conserve the infant's energy.
• Q: When should a $6$-month-old with Tricuspid Atresia definitely receive supplemental oxygen?
  • A: During stressful events that increase oxygen demand, such as when a technician comes to draw blood for serum electrolytes.
• Q: A $4$-year-old is $4$ days post-op TOF repair. HR $130$, RR $32$, B/P $64/46$, UOP $10\,ml/hr$, weight up $0.5\,lbs$. Best action?
  • A: Consider early heart failure (evidenced by weight gain and low urine output) and notify the practitioner.