Understanding Perfusion and Congenital Heart Disease

• Perfusion is the flow of blood through arteries and capillaries.
• Perfusion delivers nutrients/oxygen to cells and removes cellular waste products.
• It allows for transport of oxygen rich hemoglobin to cells and returns CO2 hemoglobin to alveoli.
• Antecedents of perfusion include a functional pump, vessels, and vasculature.
• Impaired perfusion can lead to poor cardiac output, thrombi, emboli, and vessel narrowing.
• Outcomes of impaired perfusion can be ischemia, necrosis, respiratory acidosis, and death.

Basic Facts about Congenital Heart Disease (CHD)

• CHD affects roughly 1 in every 100 infants.
• Approximately 40,000 infants in the US are affected by CHD annually.
• Of those, about 25,000 require medical intervention in the first year.
• There are over 40 types of heart defects.

Causes of CHD

• CHD has a multi-factorial origins including genetic and enviornmental .
• Risk factors include maternal diabetes, alcohol ingestion, smoking, and exposure to toxins such as lithium, hormones, and amphetamines.
• Exposure to infections such as Rubella, as well as a family history of CHD increase the risk.
• Associations with syndromes and chromosomal anomalies such as Down Syndrome, Trisomy 13, Trisomy 18, Noonan Syndrome, Williams Syndrome, DiGeorge Syndrome, Marfan Syndrome, and Turner Syndrome all linked to CHD.

How CHD Forms

• The heart begins developing at conception and is fully formed by 8 weeks.
• Congenital heart defects often arise if crucial steps during these 8 weeks do not occur properly.

Differences in Fetal Circulation

• In the fetus, blood entering the heart already contains oxygen provided by the placenta from the mother.
• Only a small amount of blood circulates through the non-functional lungs.
• The majority of blood bypasses the lungs through two structures: the foramen ovale and the ductus arteriosus.
• The foramen ovale is a hole between the right and left atria.
• The ductus arteriosus is a blood vessel connecting the pulmonary artery and the aorta.

Transition from Fetal to Newborn Circulation

• Prenatally, the placenta provides oxygen-rich blood, so the blood bypasses the lungs through the PDA and FO
• There is high pulmonary vascular resistance (PVR) and low systemic vascular resistance (SVR).
• The high PVR forces blood through the ductus and FO, delivering mom's oxygen-rich blood to the vital organs.
• After birth, the baby takes its first breath, opening up the lungs, and physiologic changes trigger a decrease in PVR.
• The FO closes due to increased pressure.
• The PDA is stimulated to close due to local mediators.
• The umbilical cord is clamped, and the SVR increases, causing blood to take the normal path through the heart and lungs.
• Foramen Ovale (FO) is a hole between the right and left atria.
• Patent Ductus Arteriosus (PDA) is a connection between the pulmonary artery and aorta.

Basic Concepts of Circulation

• Major circulatory changes occur at birth.
• Blood flows from high to low pressure, following the path of least resistance.
• After birth, SVR is high and PVR is low.

General Signs and Symptoms of CHD

• Respiratory distress
• Fatigue
• Failure to thrive
• Murmur
• Cyanosis, especially when crying
• Delayed capillary refill
• Diminished peripheral pulses

Congenital Hearts Disease Classifications

• CHD is classified based on altered hemodynamics.
  • Increased pulmonary blood flow
  • Obstructive
  • Decreased pulmonary blood flow
  • Mixed blood flow

Shunting

• Left-to-right shunting involves oxygenated blood shifting from the left to the right side of the heart, re-entering pulmonary circulation, increasing the workload on the right side.
• Right-to-left shunting involves unoxygenated blood being shunted from the right to the left side of the heart through a septal opening or vessel connection and then entering systemic circulation.

Defects with Increased Pulmonary Blood Flow

• Atrial Septal Defect (ASD)
• Ventricular Septal Defect (VSD)
• Patent Ductus Arteriosus (PDA)
• Atrioventricular Canal (AVC/CAVC)

Clinical Manifestations of CHD with Increased Pulmonary Blood Flow

• Congestive Heart Failure (CHF)
• Tachypnea & Tachycardia
• Decreased UOP
• Sweating
• Fatigue
• Weakness
• Difficulty with feeding
• Weight loss or poor weight gain
• Pale, cool extremities
• Cardiomegaly
• Retractions, nasal flaring, grunting, and respiratory distress
• Hepatomegaly
• Ascites
• Peripheral edema
• Murmur
• Atrial dysrhythmias
• Risk for development of pulmonary vascular obstructive disease.

CHD: Atrial Septal Defect (ADS)

• ASD is the failure of the entire atrial septum to close, resulting in communication between the right and left atrium
• Results in Left-to-Right Shunt
• Can be asymptomatic
• Will present with a murmur

ASD Management

• Observation if asymptomatic; the hole may close on its own
• Surgical treatment with patch closure which requires a full open heart surgery with cardiopulmonary bypass
• Non-Surgical Treatment depending on the location/type of hole, catheterization with Amplatzer Septal Occluder can be done
• Prognosis <1% mortality with surgery

CHD: Ventricular Septal Defect (VSD)

• VSD is an abnormal opening between the left and right ventricles
• VSDs are frequently associated with other defects
• Results in Left-to-Right Shunt
• Clinical signs and symptoms include CHF and a characteristic murmur

VSD Management

• 20-60% will spontaneously close in the first year
• Complete surgical repair including open-heart surgery with cardiopulmonary bypass may be required. A patch or suture are used depending on size.
• Non-surgical repair performed through cardiac catheterization is an option to repair.

CHD: Atrioventricular Canal Defect (AVC)

• Incomplete fusion of endocardial cushions results in low ASD, high VSD, and incomplete formation of tricuspid and mitral valves.
• Flow dictated by SVR vs PVR
• AVC is common in Trisomy 21.
• It is usually left to right shunting
• Symptons include moderate-severe CHF, murmur, and cyanosis with agitation/crying

AVC Management

• Complete surgical repair including patch closure of septal defects and reconstruction of atrioventricular valve is required.
• Postoperative complications can include heart block, dysrhythmias, CHF, and pulmonary hypertension.
• Prognosis is a mortality rate of <5% with surgery.
• Mitral regurgitation is common later in life.

CHD: Patent Ductus Arteriosus (PDA)

• PDA results from failure of the ductus arteriosus to close in the first weeks of life
• PDA causes a left-to-right shunt
• May be asymptomatic.
• Watch for CHF signs and symptoms
• A murmur is often heard

PDA Management

• Medical: Indomethacin given IV.
• Contraindications for Indomethacin include active bleeding, increased creatinine, decreased UOP, or decreased platelet count.
• Surgical: Ligation of the vessel or placement of a metal clip.
• Non-surgical: Heart catheterization to place coils within the vessel.

Management of CHD with Increased Pulmonary Blood Flow

• Patients will exhibit an increased energy expenditure because of increasing workload on the Cardiac & Respiratory system.
• Main Goal of therapy is to minimize CHF symptoms and reduce their energy expediture.
• Anti-Failure Medications commonly used, including:
  • Digitalis
  • Diuretics
  • Captopril

Types of Obstructive Defects

• Coarctation of Aorta
• Aortic Stenosis
• Pulmonic Stenosis

CHD: Obstructive Defects

• Anatomic narrowing causes obstruction of blood-flow to the systemic circulation.
• Leads to:
  • Low cardiac output
  • increased pressure in ventricles and vessels prior to obstruction.

CHD: Coarctation of Aorta

• Obstruction to the left ventricle through the aorta.
• Leads to decreased cardiac output and blood getting to systemic circulation.

Clinical Manifestations Of Coarctation of Aorta

• May have high blood pressure in arms
• Bounding pulses in arms and/or jugular vein distention (JVD)
• Diminished pulses in lower extremities and cool skin
• A discrepancy in blood pressure between the upper and lower extremities may be apparent
• Infants may have signs/symptoms of congestive heart failure
• In older children, dizziness, headaches, and fainting may occur

Management of Coarctation of the Aorta.

• Treatment decisions can be Surgical and Non-surgical.
• Surgical: Especially for infants less than 6 months. End-to-end anastamosis of the aorta or enlargement of the constricted area using a graft
• Non-surgical: Balloon angioplasty can be done in older infants and children. Decisions are based on individual cases/narrowing of the aorta

CHD: Aortic Stenosis

• Aortic Stenosis is a stricture of the aortic valve that increases resistance to blood flow as it leaves the left ventricle.
• Aortic Stenosis causes decreased Cardiac Output, pulmonary congestion, and increased work on the left ventricle
• The increased work of LV causes hypertrophy which causes a thickening in the heart wall and heart muscle.

CHD: Pulmonic Valve Stenosis

• Narrowing at the entrance to the pulmonary artery resulting in decreased pulmonary blood flow and increased workload to the right ventricle.
• Increase workload to RV results in Right Ventricular Hypertrophy (thickening of ventricle).

CHD Lesions with Decreased Pulmonary Blood Flow

• Tetralogy of Fallot
• Tricuspid Atresia
• These conditions are cyanotic lesions.

CHD: Tetralogy of Fallot (TOF)

• TOF Involves consisting 4 Defects:
  • Ventricular Septal Defect (VSD)
  • Pulmonary Stenosis
  • Overriding Aorta
  • Right Ventricular Hypertrophy

CHD: Tetralogy of Fallot (TOF) Assessments

• Infants may be acutely cyanotic at birth or mildly; cyanosis worsens as pulmonary stenosis increases.
• Infants will do better if PDA is present
• Characterized by a murmur
• Hypercyanotic episodes AKA "Tet" Spells caused by acute hypoxia during feeding, crying, or stooling. Resulting in Right-to-left shunting
• Children present with Chronic hypoxemia/poor growth/use of "squatting" position when in distress.

CHD: Tetralogy of Fallot (TOF) Intervention

• Knee To Chest position
• Calm the Patient
• Provide Oxygen
• Morphine

CHD: Tetralogy of Fallot (TOF) Management

• Complete Repair done in 1st year of life when increasing cyanosis/Tet Spells occur.
• Palliative Shunt (Blalock-Taussig Shunt/BT Shunt) will increase pulmonary blood-flow/oxygen saturation in the lungs.
• Palliative Shunt has a Mortality rate of less than 3% total correction; risk of Post-op symptoms of CHF.

CHD: Mixed Blood Flow

• Transposition of the Great Arteries
• Total Anomalous Venous Return
• Truncus Arteriosus
• Hypoplastic Left Heart Syndrome

CHD: Transposition of the Great Arteries

• Aorta leaves RV; pulmonary artery leaves LV
• Minimal communication between pulmonary/circulatory systems.
• Unoxygenated blood leaves RV for Systemic Circulation.
• Severely cyanotic at time of birth, unless PDA/ASD/VSD are present

CHD: Transposition

• For survival, communication and mixing of blood are essential.
• Newborns require administration of Prostaglandin E-1 as IV for continuous PDA assistance.
• Can do Balloon atrial septostomy to enlarge an ASD if needed
• Patients require an Atrial Switch Operation is required in the first weeks of life.

CHD: Hypoplastic Left Heart Syndrome (HLHS)

• HLHS is an Underdeveloped left side of the heart
• patients need a PDA allowing blood to go to systemic circulation, past the narrowed Ao.

CHD: Hypoplastic Left Heart Syndrome (HLHS) Assessments

• HLHS Signs/Symptoms include:Mild cyanosis at birth
• HLHS Signs/Symptoms include:Rapid deterioration when PDA closes causing
• HLHS Signs/Symptoms include:Decreased CO leading to serve Cardio-vascular collapse.
• HLHS is fatal if not treated. (1st month of life.)
• HLHS requires Prostaglanden E-1 to keep PDA patent open.

CHD: Hypoplastic Left Heart Syndrome (HLHS) Treatment

• Norwood Procedure
• BT shunt.
• Hemi-Fontan or Bidirectional Glenn
• Modified Fontan

CHD: Care Management Process

• Expected Outcomes
• Assessments
• Nursing Diagnoses
• Interventions
• Collaboration

CHD: Expected outcomes

• Child’s Growth/Development progresses regularly
• Gas exchange is Maximized
• Workload on the heart is minimized
• Family develops positive coping strategies

CHD: Assessments Include:

• Prenatal Diagnostics for early Dx intervention involving Prenatal Care with ultrasounds
• Respiratory involving Rate/Effort and Saturation levels: Cardiac including Rate/Rhythm/Peripheral Perfusion.
• Peripheral Edema (liver)
• Growth/Development involving growth charts/assessment tools

CHD: Diagnostic Test include:

• Chest X-Ray
• Electrocardiogram
• Echocardiogram
• Cardiac Catheterization
• Blood Counts.

CHD Nursing Diagnosis Include:

• Impaired gas exchange
• Altered tissue perfusion
• Risk for decreased Cardiac Output
• Altered Nutriton less and body requirement.
• Risk for impaired growth development.
• Risk for infection
• Anxiety, for ineffective family coping

CHD: Interventions Address

• Family Anxiety:
  • Assess Coping Mechanisms Regularly
  • Provide Resources like group-therapy/family support.
  • Small/Frequent Nutritious Meals.
  • Increase Caloires using supplemental forulas to Soft-nipples to maximize suck & allow the patient to have good res
  • Development:
    • Educate and treat child as normal
    • Infection Control like Limit Exposure/Hand-Wash/Education
    • Pro-phylactic Antibotics if under-going Surgery or Dental procedures
    • Gas-Perfusion and Cardiac levels can be sustained with Oxygen intake
    • Activities are to be limited during hypercyanotic spells using knee to chest position
    • Anti-Failure Medication like Digitalis/Diuretics/ACE inhibitors that promote good hygiene.

CHD: Collaboration is Key

• Multi-Disicplinary Approach
  • RN Case-managment
  • Cardiology/Cardiothoracic Team.
  • Nutrition and child specialist.
  • OT, PT , Pharmacy

CHD: Post-Operation Management

• Temperature
• Vital signs are to be monitored (HR/RR) full time and observation of dysrhythmias during ventilation post-op.
• Breath sounds listened to check for aterlecsis and perform careful suctioning.
• Patients are to be given pain meds such as Tylenol/Morphone/Versed.

CHD: Post-Operation Management also Focuses on

• Cardiac output.
• Monitor and maximize rest.
• Monitor and maintain fluids depending on signs of level perfusion and electrolyte balance.
• Treatment is to target tach-cardia dspenia severe and inablity for cheat tubes to chest to output and breath.