Cardiovascular Dysfunction PDF

Cardiovascular Dysfunction Chapter 42: The Child with Cardiovascular Dysfunction Cardiovascular Dysfunction Overview Types of Cardiovascular Disorders ○ Congenital Heart Disease (CHD): Refers to anatomical heart abnormalities present at birth. Clinical c...

Cardiovascular Dysfunction Chapter 42: The Child with Cardiovascular Dysfunction Cardiovascular Dysfunction Overview Types of Cardiovascular Disorders ○ Congenital Heart Disease (CHD): Refers to anatomical heart abnormalities present at birth. Clinical consequences often lead to two major issues: Heart Failure (HF): The heart's inability to pump blood effectively. Hypoxemia: Low blood oxygen levels due to inefficient blood circulation. ○ Acquired Heart Disorders: Develop after birth and may affect either a normal heart or one with congenital defects. Factors contributing to these disorders include: Infections (e.g., myocarditis) Autoimmune responses (e.g., rheumatic fever) Environmental factors Genetic/familial tendencies History and Physical Examination ○ Health History: Inquire about maternal health (e.g., diabetes, lupus) and any teratogenic medications used during pregnancy (e.g., phenytoin). Assess for substance use (alcohol, illicit drugs) which increases risk for CHD. Consider infections during pregnancy (e.g., rubella) that can lead to congenital anomalies. Note birth weight implications; low or high birth weight can indicate increased risk for congenital heart defects. ○ Family History: A detailed family history is crucial as congenital heart defects can be hereditary. Conditions like Marfan syndrome or certain cardiomyopathies have genetic links. A history of fetal loss or sudden death in family may indicate underlying heart disease. ○ Physical Assessment: Inspection:  Nutritional State: Look for failure to thrive or poor weight gain. Color: Cyanosis indicates CHD; pallor suggests poor perfusion. Chest Deformities: Enlarged hearts may distort chest shape. Unusual Pulsations: Visible neck vein pulsations can occur in some conditions. Respiratory Excursion: Assess for tachypnea or dyspnea. Clubbing of Fingers: Associated with chronic hypoxia. Palpation and Percussion: Assess heart size, thrills, and any abnormal findings in the abdomen (e.g., hepatomegaly). Auscultation: Evaluate heart rate, rhythm, and character of heart sounds (listen for murmurs or additional sounds). Diagnostic Evaluation Procedure Description Chest radiography (x-ray) Provides information on heart size and pulmonary blood flow patterns Electrocardiography (ECG) Graphic measure of electrical activity of heart Holter monitor 24-h continuous ECG recording used to assess dysrhythmias Echocardiography Use of high-frequency sound waves obtained by a transducer to produce an image of cardiac structures Transthoracic Done with transducer on chest M-mode One-dimensional graphic view used to estimate ventricular size and function Two-dimensional Real-time, cross-sectional views of heart used to identify cardiac structures and cardiac anatomy Doppler Shows blood flow patterns and pressure gradients across structures Fetal Imaging fetal heart in utero Transesophageal Transducer placed in esophagus behind heart to obtain images of echocardiography (TEE) posterior heart structures or in patients with poor images from chest approach Cardiac catheterization Imaging study using radiopaque catheters placed in a peripheral blood vessel and advanced into heart to measure pressures and oxygen levels in heart chambers Hemodynamics Measurements of pressures and oxygen saturations in heart chambers Angiography Use of contrast material to illuminate heart structures and blood flow patterns Biopsy Use of special catheter to remove tiny samples of heart muscle for microscopic evaluation; used in assessing infection, inflammation, or muscle dysfunction Electrophysiology study Special catheters with electrodes inserted to record electrical activity (EPS) from within the heart; used to diagnose rhythm disturbances Exercise stress test Monitoring of heart rate, BP, ECG, and oxygen consumption at rest and during progressive exercise on a treadmill or bicycle Cardiac MRI Noninvasive imaging technique; used in evaluation of vascular anatomy outside of the heart (e.g., COA, vascular rings), estimates of ventricular mass and volume ○ Electrocardiogram (ECG) Purpose: Measures the electrical activity of the heart, providing crucial information on heart rate, rhythm, abnormal rhythms, conduction issues, and ischemic changes. Standard Procedure: Utilizes 12 leads to capture different views of the heart; the procedure takes about 15 minutes. Special care may be needed for infants and young children, as they can be fussy during lead placement. Bedside Monitoring: A single lead ECG is commonly used in pediatric settings, particularly for children with heart disease. Alarms can be configured based on individual patient requirements to alert staff if the heart rate goes above or below set parameters. Electrode Placement: Electrodes are typically color-coded: white for the right side, green or red for ground, and black for the left. It’s critical to check that electrodes are placed correctly to ensure accurate readings. ○ Echocardiography  Method: Utilizes ultra-high-frequency sound waves delivered by a transducer placed on the chest, creating images of the heart’s structure by processing the returning echoes. Common Use: It is the most frequently used test for assessing cardiac anatomy and detecting dysfunction in children. Fetal echocardiography can lead to prenatal diagnoses of congenital heart defects. Procedure Duration: A full echocardiogram can last about an hour. The child must lie still, which may necessitate conscious sedation or anesthesia for infants and young children, while older children might benefit from preparation techniques like distraction through videos. Nursing Alert: Electrodes for cardiac monitoring are often color coded: white for right, green (or red) for ground, and black for left. Always check to ensure that these colors are placed correctly. ○ Cardiac Magnetic Resonance Imaging (MRI) Function: Uses magnetic fields and radio wave pulses to produce real-time 3D images of both intracardiac and extracardiac structures, and assesses ventricular function. Indications: Particularly useful for older children and adolescents needing detailed quantitative information (like ventricular chamber volume and valve regurgitation) that echocardiography cannot provide. MRI use has increased significantly in recent years. Procedure Considerations: Generally noninvasive but can take over an hour, requiring patients to remain still. Children under 7, those with claustrophobia, or those with developmental delays may need sedation. Patients with metal implants, such as pacemakers, cannot undergo MRI due to safety concerns. ○ Cardiac Catheterization Procedure: Involves the insertion of a radiopaque catheter through a large-bore needle into a peripheral vessel, guided to the heart with fluoroscopy. This allows for pressure measurements and imaging of blood circulation inside the heart (angiography). Types: Diagnostic Catheterizations: Used to diagnose congenital heart defects, often in symptomatic infants. This can involve right-sided catheterizations through veins or left-sided through arteries. Interventional Catheterizations: Use balloon catheters or devices to alter cardiac anatomy, such as dilating stenotic valves or closing abnormal connections.  Electrophysiology Studies: Involve catheters with electrodes that assess electrical activity to diagnose dysrhythmias and may include ablation techniques to eliminate abnormal pathways. Risks and Complications: While routine, catheterization carries risks, especially for neonates and critically ill children, including radiation exposure, allergic reactions to contrast material, and potential complications like hemorrhage, vascular injury, and rare severe events such as stroke. Intervention Diagnosis Balloon atrial septostomy Transposition of the great vessels Other complex defects Balloon dilation Valvar pulmonary stenosis Branch pulmonary artery stenosis Congenital valvar aortic stenosis Rheumatic mitral stenosis Recurrent coarctation of the aorta Stent placement Pulmonary artery stenosis Coarctation of the aorta in adolescents Coil occlusion Small patent ductus arteriosus Collateral vessels in single-ventricle patients Transcatheter device closure Some atrial septal defects (secundum type) Larger patent ductus arteriosus Fenestrations following Fontan procedures Transcatheter pulmonary Incompetent pulmonary valves following surgery to repair valve replacement right ventricular outflow tract Radiofrequency (RF) ablation Some tachydysrhythmias ○ Preprocedural Care Assessment: A comprehensive nursing assessment is vital to minimize complications, including accurate height and weight for catheter selection, history of allergies (especially to iodine-based contrast), and screening for signs of infection. Patient Preparation: Involves explaining the procedure to children and families at their developmental level. School-age children may benefit from detailed explanations, while adolescents can use personal devices for distraction. ○ Postprocedural Care Setting: Care may occur in a recovery unit, hospital room, or ICU, based on the patient's acuity. Many interventional procedures require overnight hospital observation, though some may be outpatient. Monitoring: Patients are placed on cardiac monitors and pulse oximeters for initial recovery hours. Nursing Responsibilities Complication Observation: ○ Pulses: Check equality and symmetry, noting that distal pulses may be weaker initially but should improve. ○ Temperature and Color: Monitor the affected extremity for coolness or blanching, which may indicate arterial obstruction. ○ Vital Signs: Take every 15 minutes, with a focus on heart rate for dysrhythmias or bradycardia. ○ Blood Pressure: Watch for hypotension, which could signal hemorrhage. ○ Dressing Inspection: Check for bleeding or hematoma formation at the catheter site. ○ Fluid Intake: Ensure adequate hydration via IV and oral fluids to prevent hypovolemia. ○ Blood Glucose Levels: Monitor for hypoglycemia, especially in infants needing IV dextrose. Nursing Alert: If bleeding occurs, direct continuous pressure is applied 2.5 cm (1 inch) above the percutaneous skin site to localize pressure over the vessel puncture. Positioning and Activity Bed Rest: Maintain the affected extremity straight for 4-6 hours post-venous catheterization or 6-8 hours post-arterial catheterization. Use parent support for younger children who struggle to comply.  Diet: Resume normal diet as tolerated, starting with clear liquids. Encouragement to Void: Helps clear contrast material from the body. Infection Prevention Protect the catheter site from contamination, especially in diapered children, by covering with plastic film. Family-Centered Care Instructions Site Care: Cover insertion site with an adhesive bandage, changing daily for two days. Keep the site clean and dry, avoiding tub baths and swimming. Monitoring: Observe the site for redness, swelling, drainage, and bleeding; report any concerns to the practitioner. Activity Restrictions: Encourage rest and limit strenuous activities for the first three days. Diet: Resume regular diet without restrictions. Pain Management: Use acetaminophen for discomfort. Follow-Up: Attend all follow-up appointments as instructed. Congenital Heart Disease (CHD) Incidence and Mortality: ○ CHD affects about 1 in 110 live births in the U.S., with about 25% of cases classified as critical, needing intervention in the first year. ○ Nearly 48% of deaths due to CHD occur within the first year. However, mortality rates have improved significantly, thanks to surgical and catheter-based interventions, early detection, and pharmaceutical advancements. ○ In 2010, an estimated 2.4 million people with CHD were living in the U.S., including 1 million children. Causes and Risk Factors: ○ While the exact cause of CHD is often unknown, it’s generally thought to result from a combination of genetic and environmental factors. ○ Known maternal risk factors include chronic illnesses like diabetes, poorly controlled phenylketonuria, alcohol use, and exposure to environmental toxins or infections. ○ Family history of heart defects, especially in first-degree relatives, increases the likelihood, with left-sided defects showing higher familial risk. Associated Syndromes and Conditions: ○ CHD often coexists with chromosomal abnormalities, such as Down syndrome (trisomy 21) and trisomies 13 and 18.  ○ Syndromes associated with specific heart defects include: DiGeorge syndrome (22q11.2 deletion): linked with heart defects, immune deficiencies, cleft palate, and developmental issues. Noonan syndrome: commonly involves pulmonic valve abnormalities and cardiomyopathy. Williams syndrome: associated with aortic and pulmonic stenosis. Holt-Oram syndrome: features upper limb abnormalities and atrial septal defect. ○ Extracardiac abnormalities, such as tracheoesophageal fistula, renal issues, and diaphragmatic hernia, may be present alongside CHD. Circulatory Changes at Birth: ○ Prenatally, oxygenated blood enters the fetal heart via the inferior vena cava, bypassing the non-functional fetal lungs. ○ Blood flow changes at birth as the lungs expand, reducing pulmonary pressure and closing the foramen ovale and ductus arteriosus due to increased oxygen. Hemodynamics in Heart Defects: ○ Blood naturally flows from areas of higher to lower pressure, impacting how defects influence circulation: Left-to-right shunts: where blood flows from higher-pressure left to lower-pressure right chambers, can lead to increased pulmonary blood flow and heart failure. Right-to-left shunts: there’s increased pulmonary resistance or obstructions in the right heart, leading to cyanosis. Mixed blood flow defects: where oxygenated and deoxygenated blood mix, can lead to variable symptoms like hypoxemia and heart failure. Classification of Defects: ○ Traditional classification divides defects into cyanotic and acyanotic, but this can be misleading as symptoms vary. ○ A hemodynamic-based classification is more clinically useful: Increased pulmonary blood flow: left-to-right shunts leading to heart failure. Decreased pulmonary blood flow: causing cyanosis. Obstructive defects: block blood flow from ventricles; right-sided obstructions lead to cyanosis, left-sided cause heart failure. Mixed blood flow: leads to complex symptoms, often both hypoxemia and heart failure. Defects with Increased Pulmonary Blood Flow ○ Overview  These cardiac defects allow blood to flow abnormally from the left (high pressure) to the right (low pressure) side, increasing pulmonary circulation and often resulting in symptoms of heart failure (HF). Common defects: Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), Atrioventricular Canal Defect, and Patent Ductus Arteriosus (PDA). ○ Atrial Septal Defect (ASD): Description: ASD is an abnormal opening between the atria, causing oxygen-rich blood to flow from the left atrium into the right atrium. Types: Ostium primum: Located at the lower end of the septum, may involve mitral valve anomalies. Ostium secundum: Centrally located, the most common type. Sinus venosus: Near the superior vena cava junction, possibly linked with anomalous pulmonary vein connections. Pathophysiology: Despite a small pressure difference, the increased flow from the left to the right atrium raises pulmonary blood flow due to low resistance in the right atrium. The right side can manage this increased volume without significant stress initially, so HF is rare unless left untreated. Clinical Manifestations: Many patients are asymptomatic; spontaneous closure is more likely in younger patients or with smaller defects. Without closure, HF, atrial dysrhythmias, and pulmonary vascular disease risk increase later in life. Treatment: Surgical closure: Moderate to large defects are closed with a pericardial or Dacron patch, typically before school age, to prevent complications. Transcatheter closure: For suitable ASDs, a device (e.g., Amplatzer occluder) is used, often allowing outpatient treatment. Patients may need low-dose aspirin for six months post-procedure. Prognosis: Very favorable, with comparable success between surgical and transcatheter methods. Transcatheter procedures may have higher reintervention rates but shorter hospital stays. ○ Ventricular Septal Defect (VSD): Description: VSD is an opening between the ventricles, with most defects occurring in the membranous part of the septum. Defect sizes vary widely and may involve other heart abnormalities. Pathophysiology: Blood flows from the high-pressure left ventricle into the right ventricle, leading to pulmonary overcirculation and potential  pulmonary vascular resistance increase. This can cause hypertrophy in the right ventricle and, if prolonged, right atrial enlargement. Clinical Manifestations: Heart failure is a common symptom, and a murmur is typically present. Many VSDs close on their own, particularly smaller ones within the first year of life. Treatment: Palliative: For complex or multiple defects, pulmonary artery banding may reduce blood flow temporarily in infants. Complete repair: Preferred in infancy, involves suture repair for small defects and a Dacron patch for larger ones. Access is usually through the right atrium. Transcatheter closure: While widely used, transcatheter closure has a higher risk of complications, such as AV block, compared to ASD procedures. Prognosis: Generally excellent for single defects, with low mortality; however, risks increase for multiple muscular defects or additional anomalies. ○ Atrioventricular Canal Defect: Description: Also called AV septal defect, this defect is due to incomplete endocardial cushion fusion, creating an ASD and VSD, along with malformed AV valves. Blood can flow freely between all four heart chambers, often seen in children with Down syndrome. Pathophysiology: Initially, high pulmonary resistance minimizes shunting, but as it decreases, left-to-right shunting intensifies, leading to pulmonary congestion and HF. Clinical Manifestations: Moderate to severe HF symptoms, a characteristic murmur, and potential cyanosis, especially with crying. High risk for pulmonary vascular disease. Treatment: Palliative: Pulmonary artery banding may help infants with severe symptoms until complete repair is possible. Complete repair: Involves patching the septal defects and reconstructing the AV valve. Postoperative complications include heart block, mitral regurgitation, HF, and dysrhythmias. Prognosis: Generally good, but younger or smaller patients may face higher risk. Mitral regurgitation can occur over time, potentially requiring further valve intervention. ○ Patent Ductus Arteriosus (PDA):  Description: PDA results when the fetal ductus arteriosus fails to close, allowing continuous blood flow from the aorta to the pulmonary artery, causing a left-to-right shunt. Pathophysiology: The shunt's effect varies with its size; typically, systemic pressure eventually exceeds pulmonary pressure, leading to blood flow from the aorta to the pulmonary artery, which increases left heart workload and pulmonary congestion. Clinical Manifestations: A machinery-like murmur is a classic sign. Depending on shunt size, patients may be asymptomatic or show HF symptoms. Larger PDAs may lead to reversible pulmonary hypertension or left-sided volume overload. Treatment: Medical: Indomethacin can close PDA in premature infants by inhibiting prostaglandins. Surgical: Involves division or ligation through a thoracotomy. Video-assisted thoracoscopic surgery may use clips to occlude the ductus. Transcatheter: Coils can be placed to occlude PDA in the catheterization lab, with surgery reserved for specific cases (e.g., preemies or large PDAs). Prognosis: Very good for both surgical and nonsurgical methods, with low mortality. Premature infants with significant additional health issues may have higher risk. Obstructive Defects ○ Overview of Obstructive Defects: Obstructive heart defects involve anatomical narrowing (stenosis) that restricts blood flow out of the heart, creating increased pressure before the obstruction and decreased pressure beyond it. Narrowing can occur in three main locations: Valvar: At the valve itself. Subvalvar: Below the valve in the ventricle (ventricular outflow tract). Supravalvar: In the great artery above the valve. Common types of obstructive defects include Coarctation of the Aorta, Aortic Stenosis (including Valvular Aortic Stenosis), and Pulmonic Stenosis. ○ Coarctation of the Aorta (CoA): Description: Narrowing of the aorta, usually near the ductus arteriosus, causing high pressure in the upper body (head and arms) and low pressure in the lower body (abdomen and legs).  Pathophysiology: Results in increased blood pressure above the obstruction and decreased blood flow below it, potentially leading to severe acidosis and hypotension in critical cases. Clinical Manifestations: High blood pressure and bounding pulses in the arms, weak femoral pulses, cool lower extremities, and symptoms of heart failure (HF) in infants. Older children may experience dizziness, headaches, fainting, and nosebleeds. Treatment: Surgical Repair: Preferred for infants and patients with complex anatomy, involving either resection with re-anastomosis or graft enlargement. Postoperative hypertension is managed with IV medications initially. Transcatheter Treatment: Balloon angioplasty is common for older children, and stents may be used to maintain patency in adolescents. Prognosis: Generally good, with low morbidity and mortality. Risks include recoarctation, aortic aneurysm, and systemic hypertension. ○ Aortic Stenosis (AS): Description: Narrowing of the aortic valve restricts blood flow from the left ventricle, resulting in decreased cardiac output, left ventricular hypertrophy, and potential pulmonary congestion. AS often involves malformed valve cusps, resulting in a bicuspid valve instead of the normal tricuspid structure. Pathophysiology: The aortic outflow tract narrowing increases left ventricular workload, causing hypertrophy. Left atrial pressure may also rise, leading to pulmonary congestion and pulmonary edema if left untreated. Clinical Manifestations: Newborns with critical AS exhibit low cardiac output signs (faint pulses, hypotension, tachycardia). In children, symptoms include exercise intolerance, chest pain, dizziness, and a characteristic murmur. Treatment: Surgical (Valvular AS): Aortic valvotomy can be performed under inflow occlusion. In severe cases, additional procedures may be required, including: ○ Ross Procedure: Replacing the aortic valve with the patient’s own pulmonary valve, which is then replaced with a homograft. ○ Konno Procedure: Widening the left ventricular outflow tract with patch enlargement and valve replacement.  Nonsurgical: Balloon angioplasty is often the first-line approach, dilating the narrowed valve in the catheterization lab. Prognosis: Complications may include aortic insufficiency, valve regurgitation, and limb ischemia. Additional surgeries may be needed, as valvotomy is palliative and may not fully restore valve function. ○ Pulmonic Stenosis (PS): Description: Narrowing at the entrance to the pulmonary artery creates resistance to right ventricular blood flow, resulting in right ventricular hypertrophy. Severe cases, such as pulmonary atresia, can entirely obstruct pulmonary blood flow. Pathophysiology: Elevated right ventricular pressure can lead to hypertrophy and increased right atrial pressure, potentially reopening the foramen ovale and causing right-to-left shunting and systemic cyanosis. Clinical Manifestations: Mild cases may be asymptomatic; severe cases involve cyanosis, HF, and a characteristic murmur. Cardiomegaly is often visible on imaging. Treatment: Surgical: Pulmonary valvotomy is rarely required, as balloon angioplasty is generally effective. Transcatheter: Balloon angioplasty is the preferred treatment, involving dilation of the valve to alleviate the obstruction. Prognosis: Low risk for both surgical and nonsurgical procedures, with potential long-term issues like restenosis or valve incompetence. Defects with Decreased Pulmonary Blood Flow ○ Overview of Defects with Decreased Pulmonary Blood Flow: These defects restrict blood flow from the right side of the heart to the lungs. This restriction increases right-sided pressure, forcing desaturated blood to shunt from the right to the left side through an atrial or ventricular septal defect. The result is decreased oxygenated blood in systemic circulation, leading to hypoxemia and cyanosis. Common defects include Tetralogy of Fallot and Tricuspid Atresia. ○ Tetralogy of Fallot (TOF): Description: TOF consists of four key defects: (1) a ventricular septal defect (VSD), (2) pulmonic stenosis, (3) an overriding aorta, and (4) right ventricular hypertrophy. Pathophysiology: Hemodynamics depend primarily on the degree of pulmonic stenosis, which restricts blood flow to the lungs, and the size of the VSD. Shunting direction is influenced by relative pressures in the pulmonary and systemic circulation:  If pulmonary resistance is high, blood shunts right to left, causing systemic desaturation. If systemic resistance is higher, blood flows left to right. Clinical Manifestations: Some infants show cyanosis at birth, while others develop it gradually as pulmonic stenosis worsens. A characteristic murmur is often heard. Tet spells (acute cyanotic episodes) can occur during stress, such as crying or feeding, where oxygen needs exceed supply, increasing the risk for seizures, loss of consciousness, or sudden death. Surgical Treatment: Elective repair, typically done in the first year, includes closing the VSD and enlarging the right ventricular outflow tract with a pericardial patch. For severe cases, a transannular patch may extend across the pulmonic valve annulus, making the valve incompetent. Prognosis: Operative mortality is under 3%. Long-term complications can include chronic pulmonary regurgitation, right ventricular enlargement, arrhythmias, and possibly aortic dilation, which may require pulmonary valve replacement. Transcatheter or surgical pulmonary valve replacement may be needed later in life. ○ Tricuspid Atresia: Description: This defect is characterized by the absence of the tricuspid valve, meaning there is no direct connection between the right atrium and the right ventricle. Blood must flow from the right atrium to the left side of the heart through an atrial septal defect (ASD) or a patent foramen ovale. Pathophysiology: Blood mixing in the left heart results in systemic desaturation, while pulmonary blood flow is reduced by associated pulmonary stenosis or transposition of the great arteries. A patent ductus arteriosus (PDA) or VSD is needed to allow some blood flow to the lungs for oxygenation. Clinical Manifestations:  Cyanosis is typically present in newborns, along with tachycardia and dyspnea. Older children may show chronic hypoxemia signs, such as clubbing of the fingers and toes. Therapeutic Management: Infants requiring pulmonary blood flow are often started on prostaglandin E1 infusions to keep the ductus arteriosus open until surgery can be performed. Surgical Treatment: Tricuspid atresia is managed with staged surgeries to create a single ventricle circulation, where the left ventricle functions as the primary pump. Prognosis: Surgical mortality is less than 5%, but outcomes depend on complexity and additional risk factors. Postoperative complications may include dysrhythmias, systemic venous hypertension, pleural and pericardial effusions, and ventricular dysfunction. Mixed Defects ○ Overview of Mixed Defects: Mixed defects cause oxygenated and deoxygenated blood to mix within the heart chambers or vessels, leading to systemic desaturation and relative pulmonary congestion. Symptoms typically include cyanosis (which may not be always visible) and signs of CHF. These defects often require multiple surgical interventions, starting within the first week of life. Common defects include Transposition of the Great Arteries, Total Anomalous Pulmonary Venous Connection, Truncus Arteriosus, and Hypoplastic Left Heart Syndrome. ○ Transposition of the Great Arteries (TGA): Description: The aorta and pulmonary artery are reversed, with the aorta arising from the right ventricle and the pulmonary artery from the left ventricle, resulting in two separate circulatory loops without direct communication. Pathophysiology: Survival depends on associated defects like an ASD, VSD, or PDA, allowing mixing of oxygenated and deoxygenated blood. A VSD increases HF risk due to high pulmonary pressure and increased pulmonary blood flow. Clinical Manifestations: Severe cyanosis and depressed function at birth in cases with minimal communication.  Larger septal defects or PDA may reduce cyanosis but increase HF symptoms. Cardiomegaly is often noted within weeks. Treatment: Preoperative: Prostaglandin E1 infusion to keep the ductus arteriosus open, and balloon atrial septostomy (Rashkind procedure) for improved mixing. Surgical: The arterial switch operation (Jatene procedure) performed in the first weeks of life, repositions the great arteries and reattaches the coronary arteries to provide normal circulation. Alternative Procedures: In older patients, Senning or Mustard intra-atrial baffle repairs are occasionally encountered but have higher long-term risks. Prognosis: Generally good with the arterial switch; long-term complications may include neoaortic and coronary issues. Older baffle procedures carry increased risks of right ventricular failure and arrhythmias. ○ Total Anomalous Pulmonary Venous Connection (TAPVC): Description: The pulmonary veins connect abnormally to the systemic venous system, not the left atrium, resulting in mixed blood returning to the right atrium. Pathophysiology: An ASD or patent foramen ovale is required for blood to reach the left atrium and enter systemic circulation. Pulmonary blood flow is often increased, which can lead to pulmonary congestion and HF. The infradiaphragmatic form often leads to severe pulmonary obstruction and is a surgical emergency. Clinical Manifestations: Cyanosis is typically evident early. Severity correlates inversely with pulmonary blood flow. With unobstructed TAPVC, symptoms may emerge in infancy as pulmonary vascular resistance decreases. Obstruction worsens cyanosis and rapidly deteriorates the infant’s condition. Surgical Treatment: Corrective repair involves reattaching the pulmonary veins to the left atrium and closing the ASD. The infradiaphragmatic type has the highest risk of morbidity and mortality. Prognosis: Generally favorable, with less than 10% mortality. Morbidity increases in cases with pulmonary vein obstruction. ○ Truncus Arteriosus: Description: The pulmonary artery and aorta fail to separate, forming a single vessel that receives mixed blood from both ventricles. Pathophysiology: Mixed blood flows to the pulmonary and systemic circulations. Pulmonary vascular resistance typically favors increased blood flow to the lungs, leading to pulmonary vascular disease early in life. Clinical Manifestations: Infants present with moderate to severe HF, cyanosis, poor growth, and exercise intolerance. There is a characteristic murmur. Approximately 35% of cases have 22q11.2 deletions. Surgical Treatment: Early surgery within the first month includes closing the VSD and establishing separate outflow tracts for pulmonary and systemic circulation with a conduit from the right ventricle to the pulmonary artery. Multiple conduit replacements are necessary as the child grows. Prognosis: Perioperative mortality is around 10%, with higher risks if additional repairs are required. Long-term issues include truncal valve regurgitation and conduit stenosis. ○ Hypoplastic Left Heart Syndrome (HLHS): Description: Severe underdevelopment of the left side of the heart, including a small or absent left ventricle, and hypoplasia or atresia of the mitral and/or aortic valves. Blood from the left atrium flows through an ASD or patent foramen ovale to the right atrium, and systemic blood flow depends on the PDA. Pathophysiology: Blood mixing in the right heart leads to circulation through both the pulmonary artery and systemic circulation via the ductus arteriosus. Coronary and cerebral blood flow depend on retrograde flow through the hypoplastic ascending aorta. Clinical Manifestations: Mild cyanosis and HF symptoms at birth, worsening as the PDA closes, resulting in cardiovascular collapse if untreated. Therapeutic Management: Stabilization with mechanical ventilation, inotropic support, and prostaglandin E1 infusion to maintain ductal patency until surgery. Surgical Treatment: A staged surgical approach, with the right ventricle becoming the systemic pump. Alternatively, heart transplantation may be  considered, though donor shortages and immunosuppression are challenges. Prognosis: Survival has greatly improved, with approximately 90% long-term survival if the child reaches 12 months. Long-term issues include ventricular dysfunction, tricuspid regurgitation, recurrent aortic narrowing, and developmental delays. Single Ventricle Anatomy ○ Overview of Single Ventricle Anatomy: These anomalies, which include defects like Hypoplastic Left Heart Syndrome (HLHS), unbalanced complete AV canal, double-inlet left ventricle, tricuspid atresia, and pulmonary atresia with intact ventricular septum, have only one functional ventricle. A staged palliation approach is used, which involves three key surgeries to direct blood flow and reduce stress on the single ventricle. ○ Stage I - Norwood Procedure (First Week of Life): Goals: Establishes systemic blood flow, reconstructs the small aorta, and creates pulmonary blood flow. Steps: Connects the right ventricle to the aorta to serve systemic circulation. Rebuilds the aorta and attaches it to the ventricle. Creates pulmonary blood flow using either: ○ Modified Blalock-Taussig shunt: A 3-4 mm Gore-Tex tube from the subclavian artery to the pulmonary artery. ○ Sano modification: A conduit from the right ventricle to the pulmonary artery, which provides better diastolic blood pressure and coronary perfusion. Outcomes: The Norwood procedure is a critical initial step, allowing systemic and pulmonary circulation to function with only one ventricle. ○ Stage II - Bidirectional Glenn Shunt (3 to 8 Months of Age): Goals: Reduces ventricular volume overload and directs half of the deoxygenated blood passively to the lungs. Procedure: Connects the superior vena cava directly to the pulmonary artery, allowing venous blood to flow passively to the lungs without a ventricular pump. Benefits: Reduces cyanosis, lessens ventricular workload, and improves oxygen saturation. Risks include embolic events and, rarely, pulmonary arteriovenous fistulas. ○ Stage III - Fontan Procedure (2 to 4 Years of Age): Goals: Completes the separation of oxygenated and deoxygenated blood by redirecting systemic venous return to the lungs without the need for a ventricular pump. Procedure: Connects the inferior vena cava (IVC) to the pulmonary artery through an intraatrial baffle, allowing all systemic venous blood to reach the lungs. A fenestration may be added to relieve pressure. Requirements: Normal ventricular function and low pulmonary vascular resistance are essential for success. Outcomes: While the Fontan procedure doesn’t restore normal heart anatomy, it effectively separates oxygenated and deoxygenated blood, improving systemic oxygenation and reducing ventricular load. ○ Shunt Options in Single Ventricle Palliation: Modified Blalock-Taussig Shunt: Connects the subclavian artery to the pulmonary artery, used when flow to the lungs needs to be increased. It may require diuretics to manage excessive flow. Sano Modification: Connects the right ventricle to the pulmonary artery and provides better diastolic pressure. Bidirectional Glenn Shunt: Connects the superior vena cava to the right pulmonary artery, reducing cyanosis and ventricular strain. Central Shunt: Connects the ascending aorta to the main pulmonary artery, used when other shunts are unsuitable; it can restrict flow and may require diuretics. ○ Postoperative and Long-Term Concerns: Between Stages: Infants are particularly vulnerable between Stage I and Stage II, requiring close home monitoring and specialized care. Long-Term Risks: Individuals living with Fontan physiology face risks such as protein-losing enteropathy, atrial dysrhythmias, late ventricular dysfunction, and developmental delays. Lifelong Care: Patients require frequent follow-ups, medical management, and possible re-interventions to manage complications and maintain heart function. Congestive Heart Failure Definition: ○ Congestive Heart Failure (CHF): Inability of the heart to pump adequate blood to meet the body’s demands due to structural abnormalities, myocardial failure, or excessive demand on the heart. Pathophysiology: ○ Types of Heart Failure: Right-sided HF: Right ventricle fails to pump blood effectively, leading to systemic venous congestion, hepatosplenomegaly, and sometimes edema. Left-sided HF: Left ventricle fails to pump blood to the body, causing pulmonary congestion and pulmonary edema. Combined HF: Typically, both sides are affected in children due to interdependence of heart function. ○ Compensatory Mechanisms: Sympathetic nervous system activation, causing increased heart rate, force of contraction, peripheral vasoconstriction, and fluid retention. Fluid overload and increased workload exacerbate the failure. Clinical Manifestations: ○ Impaired Myocardial Function: Tachycardia, inappropriate sweating (scalp), decreased urinary output, fatigue, weakness, anorexia, pale/cool extremities, weak peripheral pulses, gallop rhythm, and cardiomegaly. ○ Pulmonary Congestion: Tachypnea, dyspnea, retractions (in infants), nasal flaring, exercise intolerance, orthopnea, cough, hoarseness, cyanosis, wheezing, and grunting. ○ Systemic Venous Congestion: Weight gain, hepatomegaly, peripheral edema (notably periorbital), ascites, and neck vein distention. Diagnostic Evaluation: ○ Diagnosis based on clinical symptoms, including tachypnea, tachycardia at rest, dyspnea, and feeding intolerance. ○ Imaging and tests: Chest radiography (cardiomegaly), ECG (ventricular hypertrophy, rhythm issues), and echocardiogram to assess underlying cause. Nursing Alerts ○ Monitor for signs of fluid overload: Rapid weight gain, increased peripheral edema, and worsening respiratory symptoms require immediate attention. ○ Watch for signs of respiratory distress: Tachypnea, dyspnea, retractions, and cyanosis may indicate worsening HF and need prompt intervention. ○ Assess urinary output: Decreased output can signal worsening cardiac output and kidney perfusion issues.  ○ Be vigilant with feeding: Infants with HF may experience feeding intolerance; watch for signs of fatigue, sweating, or difficulty breathing during feeds. ○ Regularly check vitals: Tachycardia and tachypnea are critical signs; any abnormal changes warrant further assessment. Therapeutic Management ○ Goals of Treatment: Improve cardiac function (increase contractility, decrease afterload). Remove accumulated fluid and sodium (decrease preload, minimize fluid overload). Decrease cardiac demands to lessen the heart's workload. Improve tissue oxygenation and reduce oxygen consumption. ○ Improve Cardiac Function: Medications Used: Digitalis glycosides (Digoxin): Increases contractility, cardiac output, and reduces heart size and edema. ACE inhibitors: Cause vasodilation, reducing afterload, pulmonary, and systemic vascular resistance. Beta-blockers (Carvedilol): Decrease heart rate, BP, and promote vasodilation. Nursing Alerts Monitor serum potassium: Low potassium enhances digitalis effect, increasing risk of digoxin toxicity. High potassium diminishes its effect. Avoid potassium supplements with ACE inhibitors to prevent hyperkalemia, especially if using potassium-sparing diuretics like spironolactone. ○ Remove Accumulated Fluid and Sodium: Diuretics: The main treatment is to eliminate excess water/salt. Furosemide (Lasix): Commonly used; can cause hypokalemia, risking digitalis toxicity. Chlorothiazide (Diuril): Acts on distal tubules; causes hypokalemia. Spironolactone (Aldactone): Potassium-sparing; used with thiazides or furosemide.  Diuretic Actions Comments Nursing Care Management Furosemide Blocks reabsorption of Drug of choice in - Begin recording output as soon as drug (Lasix) sodium and water in severe heart failure; is given. proximal renal tubule; causes excretion of interferes with sodium chloride and potassium - Monitor for dehydration due to reabsorption in the (risk of hypokalemia diuresis. loop of Henle and and digitalis toxicity) - Watch for side effects (e.g., nausea, distal tubule vomiting, diarrhea, ototoxicity, hypokalemia, dermatitis, postural hypotension). - Encourage high-potassium foods and/or supplements. - Monitor chloride and acid-base balance in long-term use. - Observe for digoxin toxicity signs. Chlorothiazide Acts directly on distal Less frequently used; - Monitor for side effects (e.g., nausea, (Diuril) tubules to decrease may cause hypokalemia weakness, dizziness, paresthesia, muscle sodium, water, and acidosis in large cramps, skin eruptions, hypokalemia, potassium, chloride, doses acidosis). and bicarbonate absorption - Encourage high-potassium foods and/or supplements. Spironolactone Blocks aldosterone Weak diuretic with - Monitor for side effects (e.g., skin (Aldactone) action, promoting potassium-sparing rash, drowsiness, ataxia, hyperkalemia). sodium retention and effect; often used with potassium excretion thiazides and - Do not administer potassium furosemide; poor GI supplements. absorption; takes days for full effect  Additional Measures: Fluid restriction in acute stages if necessary. Sodium-restricted diets are infrequent but may involve avoiding extra salt and highly salted foods. ○ Decrease Cardiac Demands: Minimizing Workload: Provide a neutral thermal environment, treat infections, position in semi-Fowler to ease breathing, sedate if necessary, and minimize environmental stimuli. ○ Improve Tissue Oxygenation: Oxygen Administration: Supplemental humidified oxygen helps increase available oxygen during inspiration. Nursing Alert: Oxygen administration requires a prescription. In rare cases, oxygen may harm patients with complex heart dynamics. Quality Patient Outcomes for Heart Failure: ○ Adequate cardiac output ○ Decreased cardiac demands ○ Improved respiratory function ○ Absence of fluid excess ○ Adequate family support and education Nursing Care Management ○ Provide Expert Care to Reduce Cardiac Demands: Infants and children with CHF may require intensive care due to severe symptoms. Emotional support for both child and family is crucial, especially in end-stage cardiac disease cases. Tailored interventions for different age groups help meet care objectives effectively. ○ Improve Cardiac Function (e.g., with Digoxin): Digoxin is commonly used to improve cardiac contractility. However, it has a narrow therapeutic range, which makes correct dosing essential to avoid toxicity. Nursing Alert: Check apical pulse before Digoxin administration: Infants and young children: Withhold if pulse 2 s) Delayed (>2 s) Urine Output Decreased Decreased Decreased Decreased Level of Consciousness Irritable early Late, lethargic Decreased Decreased ○ Pathophysiology: Shock impairs circulation and oxygen delivery, triggering compensatory mechanisms like tachycardia, vasoconstriction, and hormone release to conserve fluids. This can lead to acidosis, edema, and multi-organ dysfunction, affecting the lungs, CNS, renal, and GI systems. ○ Clinical Manifestations by Shock Stage: Compensated Shock: Early signs like mild tachycardia, narrowing pulse pressure, and cool extremities. Hypotensive (Decompensated) Shock: Advanced signs like hypotension, oliguria, poor capillary filling, and confusion. Irreversible Shock: Signs include thready pulse, apnea, coma, and is generally unresponsive to treatment. ○ Therapeutic Management: Airway & Oxygenation: Immediate oxygen delivery, possibly with endotracheal intubation, to optimize blood oxygen levels. Fluid Resuscitation: IV fluids (isotonic solutions) given in boluses of 20 mL/kg, monitoring for improvements in BP and heart rate. Cardiovascular Support: Medications such as dopamine or epinephrine to boost heart output and restore adequate circulation. ○ Nursing Care Management: Positioning: Place the child flat with legs elevated to aid in circulation. Vital Monitoring: Continuous ECG, pulse oximetry, and frequent blood gas and electrolyte checks. Intensive IV and Medication Management: Careful titration and documentation of IV infusions and medications. Family Support: Frequent updates and access to the child, support for stress management.  ○ Emergency Treatment (Quick Actions): Ventilation: Secure airway, administer 100% oxygen. Fluids: Rapid IV fluids to restore volume. Inotropes/Vasopressors: Administer as ordered to support heart function. General Support: Elevate legs, keep child warm and calm. Anaphylaxis ○ Overview of Anaphylaxis: Anaphylaxis is a rapid, systemic allergic reaction that can affect the cardiovascular, respiratory, gastrointestinal, and integumentary systems. It is life-threatening and demands immediate intervention. Common allergens include drugs (like antibiotics), latex, foods, and insect venom. ○ Pathophysiology: Triggered by allergen exposure, histamine and other chemicals are released from mast cells, causing vasodilation, bronchoconstriction, and increased capillary permeability. These reactions can lead to vascular collapse, airway obstruction, and shock. ○ Clinical Manifestations: Early Symptoms: Uneasiness, irritability, anxiety, headache, dizziness, paresthesia, and skin flushing. Progressive Symptoms: Flushing, urticaria (hives), angioedema (swelling of the face, lips, tongue, etc.), bronchoconstriction, and in severe cases, laryngeal edema. Systemic Shock: Caused by vasodilation and fluid loss into interstitial spaces, leading to hypotension and decreased cardiac output. ○ Therapeutic Management: Immediate Treatment Goals: Ensure airway patency, restore circulation, and prevent further exposure. Medications: Epinephrine: Administered intramuscularly (0.01 mg/kg up to 0.3 mg), repeated if necessary. Epinephrine works to constrict blood vessels, relax bronchial muscles, and reduce histamine release. Antihistamines (e.g., diphenhydramine) and fluids may be given, especially in mild cases without respiratory or cardiovascular distress. Severe Cases: Intravenous epinephrine and vasopressors if necessary to maintain blood pressure. Oxygen therapy and airway management may require intubation or mechanical ventilation if respiratory distress is significant.  Biphasic Reaction: Monitoring is essential as symptoms can recur within hours of initial improvement. ○ Nursing Care Management: Immediate Actions: Anticipate likely reactions, recognize early symptoms, and intervene rapidly. Priority is to maintain the airway and support circulation. If a reaction occurs, place the child in a head-elevated position (unless hypotensive) to facilitate breathing. Initiate IV access for emergency medication administration, ideally giving epinephrine and other drugs intravenously if available. Monitor vital signs and urine output closely for signs of shock. Epinephrine Administration: IM injection should be given promptly, using EpiPen Jr (0.15 mg) for children 8–25 kg and EpiPen (0.3 mg) for children over 25 kg. ○ Prevention: Identify and avoid known allergens by obtaining a thorough history of allergies from parents. Label charts with known allergens and reactions. Desensitization therapy may be recommended for children with severe allergies. Education: Teach families how to use an epinephrine auto-injector and ensure the child carries it at all times. Children and families should be aware of signs of an allergic reaction and the importance of timely intervention. Encourage the use of medical identification for quick access to allergy information. ○ Nursing Alerts Immediate IM Epinephrine: The first line of defense. Never delay this treatment. Monitor for Rebound Reaction: Observe closely post-recovery, as symptoms may reappear within 4 hours (biphasic reaction). For Penicillin Allergies: Note potential for severe reactions like laryngeal edema or anaphylaxis within 1-72 hours after administration. Septic Shock ○ Overview of Septic Shock: Septic shock results from a severe infection leading to widespread inflammation (SIRS - Systemic Inflammatory Response Syndrome), impaired blood flow, and decreased oxygen delivery to tissues.  This state leads to organ dysfunction and can be fatal if untreated. Septic shock has three progressive stages. ○ Definitions Related to Sepsis and Shock: Systemic Inflammatory Response Syndrome (SIRS): Abnormal immune response to infection or noninfectious causes (e.g., burns), identified by two or more criteria including abnormal temperature, heart rate, respiratory rate, or white blood cell count. Sepsis: SIRS with a suspected or confirmed infection. Severe Sepsis: Sepsis with organ dysfunction. Septic Shock: Severe sepsis with cardiovascular dysfunction and hypotension. ○ Pathophysiology of Septic Shock: In sepsis, inflammatory mediators trigger vasodilation, increased capillary permeability, and an uneven blood flow distribution, compromising cellular oxygenation. Continued inflammation can lead to multiorgan dysfunction and eventually death. ○ Stages of Septic Shock: Early Septic Shock (Warm Stage): Signs: Fever, chills, vasodilation, warm skin, increased cardiac output. Management Focus: Support circulation and treat infection. Outlook: Best chance of survival if treated early. Normodynamic/Cold Shock (Decompensated Stage): Signs: Cool skin, diminished urine output, mental status changes. Progression: Lasts a few hours before deterioration. Management Focus: Monitoring for worsening shock and organ support. Hypodynamic/Cold Shock (Late Stage): Signs: Hypothermia, weak pulses, hypotension, oliguria or anuria, severe lethargy or coma. Outcome: Most dangerous, high risk of multiorgan failure and death. Management Focus: Intensive organ support, often requiring ICU-level care. ○ Therapeutic Management of Septic Shock: Immediate Treatment Goals: Hemodynamic Stability: IV fluid resuscitation, inotropic support. Oxygenation: Intubation and mechanical ventilation with supplemental oxygen.  Antimicrobial Therapy: Broad-spectrum antibiotics administered promptly. Source Control: Remove or drain any sources of infection (e.g., indwelling lines, abscesses). Advanced Supportive Care: Respiratory Support: Ventilation with measures to decrease lung strain due to granulocyte clumping. DIC and Multiorgan Support: Monitor and treat coagulation issues and organ failure as needed. ○ Nursing Care Management: Early Recognition and Intervention: Critical in improving outcomes. Be vigilant with vital signs and monitor for early signs such as tachypnea, tachycardia, and subtle changes in perfusion. Patient Positioning: Maintain airway, monitor oxygen levels, and keep patient comfortable. Antibiotic Administration: Initiate broad-spectrum antibiotics early; adjust based on cultures. ICU Monitoring: Patients should ideally be managed in an ICU setting for continuous monitoring, with access to advanced respiratory and cardiac support. Collaborative Approach: Work with a multidisciplinary team to ensure comprehensive support for the critically ill patient. Toxic Shock Syndrome (TSS) ○ Overview Toxic shock syndrome is a rare, potentially life-threatening condition caused by toxins produced by Staphylococcus aureus bacteria. TSS can lead to rapid multisystem organ failure and often presents similarly to septic shock. While cases of TSS linked to tampon use became prominent in the 1980s, TSS can also occur in non-menstruating individuals, including men, children, and older women. ○ Diagnostic Evaluation: Diagnosis is based on criteria established by the CDC and includes clinical signs and laboratory results: Core Diagnostic Criteria: Fever: 38.9°C (102°F) or higher Rash: Diffuse macular erythroderma Desquamation: Peeling, especially on palms and soles, 1–2 weeks after illness onset  Hypotension: Low blood pressure (systolic ≤ 90 mm Hg in adults, below the 5th percentile in children) or orthostatic symptoms (syncope, dizziness) Multisystem Involvement: Three or more organ systems affected, including gastrointestinal, muscular, mucous membrane, renal, hepatic, hematologic, or CNS TSS diagnosis is probable if four out of five major criteria are met. Cultures (blood, vaginal, cervical) should be negative for organisms other than S. aureus, and serologic tests for conditions like Rocky Mountain spotted fever, leptospirosis, and measles should also be negative. ○ Therapeutic Management: Treatment follows the general protocol for managing shock and includes: Antibiotics: Parenteral antibiotics after culture collection to target S. aureus Supportive Care: May include fluid resuscitation, respiratory support, and blood pressure stabilization Intensive Monitoring: In severe cases, hospitalization in an intensive care unit (ICU) may be necessary ○ Nursing Care and Prevention: Nursing efforts for TSS focus largely on prevention, particularly in educating menstruating individuals about safe tampon practices: Tampon Hygiene: Wash hands before and after tampon insertion Alternate between tampons and sanitary napkins, using napkins overnight or during lighter flow Avoid super-absorbent tampons, and change tampons every 4 to 6 hours