The Child with Cardiovascular Dysfunction Prepared by /miss:Amira Ali

Out line over view on Fetal circulation Physiological changes at birth Congenital Heart Disease (CHD) Cyanotic heart disease A cyanotic heart disease

Objectives At the end of these lecture all student will be able to Identify Fetal circulation mention the main Physiological changes at birth define causes of Congenital Heart Disease (CHD) Identify Cyanotic heart disease Identify A cyanotic heart disease

Fetal Circulation

Fetal Circulation Fetal circulation (prenatal circulation) differs from adult circulation in several ways and is designed to ensure a high oxygen blood supply to the brain and myocardium of the fetus.

Characteristics of fetal circulation Placenta is the source of oxygen for the fetus, it has 2 arteries and 1 vein. Fetal lungs receive less than 10% of the blood volume ; lung don’t exchange gas. Right atrium of fetal heart is the chamber with the highest oxygen concentration.

The three openings that close at birth are: Ductus Arteriosus connects the pulmonary artery to the aorta, bypassing the lungs Ductus Venosus connects the umbilical vein and the inferior vena cava bypassing the liver. Foramen Ovale is the opening between right and left atrias of the heart , bypassing the lungs.

Pattern of fetal circulation Oxygenated Blood is carried from placenta through the umbilical vein and enters the inferior vena cava thought the Ductus Venosus . This permits most of the highly oxygenated blood to go directly to the right atrium , bypassing the liver.

….. Continue pattern This right atrial blood flows directly into the left atrium through the foramen ovale an opening between the right and the left atriums .

….. Continue pattern From the left atrium blood flows directly into left ventricle and the Aorta through the subclavian arteries , to the cerebral and coronary arteries , resulting in the brain and the heart receiving the most highly oxygenated blood .

….. Continue pattern Deoxygenated blood returns from the heart and the arms through the superior vena cava, enters the right atriums and passes into the right ventricle.

Blood from the right ventricle flow into pulmonary artery, but because fetal lungs are collapsed, the pressure in the pulmonary artery is very high .

….. Continue pattern Because pulmonary resistance is high , most of the blood passes into the distal aorta through the Ductus Arteriosus, which connects the pulmonary artery and the aorta distal to the origin of the subclavian arteries. From the aorta blood flows to the rest of the body.

Normal circulatory changes at birth

Physiological changes at birth Foramen Ovale: Opening Between Atria; Allows Blood to Bypass Lungs intrauterinely; Closes With Increased Left-Sided Pressure Ductus Arteriosus: Opening Between Pulmonary Artery & Aorta; Allows Blood to Bypass Lungs intrauterinely; Closes Within 10- 15 Hours After Birth With Permanent Closure By 10-21 Days of Life

….. Physiological changes Cyanosis results from 5 or more Grams of Unoxygenated Hemoglobin per 100 ml of Blood: So, If Hemoglobin is Low, You Won’t See Cyanosis In Spite of Low PaO2!

….. physiologic Polycythemia: Increase in Production of Erythrocytes To Compensate for Chronic Hypoxemia; If Hemoglobin Greater Than 20 g/dl & Hematocrit Greater Than 55-60%, Increased Risk for thromboembolism Infants Respond to Severe Hypoxemia With BradyCardia

Normal vital signs at birth Heart rate= 120-140 beat/min Blood pressure= 65/41 mmHg Respiratory rate= 30-60 breath/min Temperature= Axillary 35.5-37oC. Oxygen saturation (SpO2 )= >93%

Congenital Heart Disease (CHD) Approximately 5-8 Per 1000 Live Births; Combination of Genetic & Environmental Factors : X-ray exposure Maternal Rubella Maternal alcoholism Maternal type 1 diabetes Maternal over 40 of age Occur EARLY in Gestation (3-8 Weeks) in the first trimester

CHD Classification of CHD: Acyanotic versus cyanotic Acyanotic Pulmonary Blood flow Obstruction to Blood flow from ventricles Pulmonary blood flow Mixed blood flow Atrial septal defect (ASD) Ventricularr septal defect (VSD) Coarctation of Aorta Aortic stenosis Tetrology of Fallot Tricuspid atresia Transposition Of great vessels Truncus arteriosus

Selected Acyanotic defects (1) ASD, or atrial septal defect: Abnormal opening between atria, allowing blood from Lt atrium (higher pressure) to go to right atrium (lower pressure). Pathophysiology: the new volume in the right ventricle is tolerable because it was sent by a low pressure from the right artium. S&S: Patients may be asymptomatic they may develop heart failure, atrial arrhythmias are present. Surgical treatment: Surgical Dacron Patch Closure . Non-surgical Repair: in catheterization, a repair pad is implanted. Patients with ASD may live several decades without S&S and the prognosis after operation is very high.

…. Cont. acyanotic (2) VSD, or Ventricular Septal Defect: It is an abnormal opening between the right and the left ventricles, resulting in a common ventricle. its found that 20% of all VSDs close spontaneously during the first year of life Pathophysiology: the blood turns from the left ventricle (higher pressure) to the right ventricle(lower pressure) causing left-to-right shunt , then to pulmonary Artery, which increases RV pressure causing RV hypertrophy and by time RV failure. S&S : congestive heart failure is common. Surgical treatment: complete repair. Non-surgical treatment: closure devise is usually implanted during cardiac catheterization

-Aortic Stenosis Stenosis of the aortic valve prevents blood from passing from the left ventricle into the aorta, leading to hypertrophy of the left ventricle S/S Usually asymptomatic but with murmur May have chest pain and even sudden death Therapeutic Management Stabilization with a Beta Blocker or Calcium Channel Blocker Balloon valvuloplasty Valve replacement Figure 41.13 Aortic stenosis: Read slide….S/S: most children are asymptomatic. A rough systolic murmur is heard loudest in the aortic space and may radiate to the right shoulder, clavicle, and up the neck. If the stenosis is severe, the child may show signs of decreased cardiac output and develop chest pain during activity. Sudden death may also occur. DX by echo. Treatment with Beta blockers or Calcium channel blockers is used to reduce cardiac hypertrophy before the defect is corrected. Balloon valvuloplasty is the treatment of choice; however, surgery may be indicated in which case a valve replacement may be performed.

Coarctation of the Aorta Narrowing of the lumen of the aorta S/S Absence of palpable femoral pulses; headache, vertigo, nosebleeds, CVA; leg pain Therapeutic Management Surgery or angiography Figure 41.14 Coarctation of the aorta is a narrowing of the lumen of the aorta due to a constricting band. This makes if difficult for blood to pass through the narrowed lumen of the aorta, causing increased blood pressure in the heart and upper portions of the body. The child may have a headache and vertigo due to the increased pressure. With younger children, irritability may be the only sign that there is a problem. Nosebleeds and cerebrovascular accidents (CVAs) may also occur due to the high pressure. Older children may complain of leg pain. Depending upon the degree of coarctation, the child may exhibit absence of palpable brachial and/or femoral pulses. Treatment involves either interventional angiography or surgery.

Selected cyanotic defect: - Tetrology of Fallot (TOF) - Tricuspid Atresia - Transposition of the Great Arteries or Vessels - Truncus Arteriosus

Tetrology of Fallot (TOF) The classic form includes four defects: (1) ventricular Septal Defect, (2) pulmonic stenosis,(3) overriding aorta, (4) right ventricular hypertrophy. Pathophysiology: the altered hemodynamic status depends on the size of the pulmonary stenosis, blood get shunted from right to left, if the pressure in the pulmonary is higher than the systemic pressure, and blood gets shunted from left to right if the systemic pressure is higher than pulmonary. S&S: cyanosis, clubbing fingers, poor growth. crying during or after feeding. Surgical treatment: complete repair is required, open heart surgery& VSD closure.

Defects with decreased pulmonary blood flow Tricuspid Atresia The tricuspid valve is closed, blood flows through the patent foramen ovale into the left atrium, bypassing the lungs. Then it is shunted back through a PDA into the lungs. When these structures close, cyanosis, tachycardia, and dyspnea occur. Surgery must correct. Treatment: IV infusion until surgery Figure 41-18 With Tricuspid Atresia, the tricuspid valve is completely closed, allowing no blood to flow from the right atrium to the right ventricle. Since blood cannot flow in the normal pattern, blood crosses through the patent foramen ovale into the right atrium, bypassing the lungs and the step of oxygenation. It is then shunted back through the PDA (patent ductus arteriosis) into the lungs. As long as these structures remain open, the child can obtain adequate oxygenation; however, once these structures close, the child will develop severe cyanosis, tachycardia, and dyspnea. Treatment consists of an IV infusion of PGE (prostaglandin) to keep the ductus open until surgery can be performed.

CONAL–TRUNCAL DEFECTS Conal–truncal defects develop during the formation of the trunk dissection. Embryologically, the pulmonary artery and the aorta begin as a large “trunk.” The ventricles then fold on themselves, the atria rise into position, and the great vessels form when the trunk twists around and separates (having a dividing wall). Transposition of the great vessels(TGA) and truncus arteriosus occur in children when there is a disruption in this process.

Transposition of the Great Arteries or Vessels SIGNS AND SYMPTOMS. Symptoms appear at birth or soon afterwards and include cyanosis, shortness of breath, poor feeding, and clubbing of the fingers and toes. DIAGNOSIS. Diagnosis is based on signs and diagnostic testing including pulse oximetry, ECG, echocardiogram, chest x-ray exam, and cardiac catheterization. If an echocardiogram is done before birth, it is called a fetal echocardiogram. Surgical treatment. TGA in all cases must be surgically corrected

Truncus Arteriosus SIGNS AND SYMPTOMS. Clinical signs and symptoms of truncus arteriosus include cyanosis, congestive heart failure, and low cardiac output. DIAGNOSIS. Diagnosis is based on signs and diagnostic testing that includes pulse oximetry, ECG, echocardiogram, chest radiograph, and cardiac catheterization. Surgical treatment. TGA in all cases must be surgically corrected

Cardiac Diseases SUBACUTE BACTERIAL ENDOCARDITIS (SBE) occurs subsequent to a bacterial infection or introduction of an infective agent into the child’s blood stream The infection may be caused by an invasive procedure such as surgery, urological procedures, or most often dental cleaning. (SBE) is most commonly seen in patients with an unrepaired congenital heart defect or valve disease, but can also occur in normal hearts

low-grade fever : malaise, loss of appetite, and muscle aches SIGNS AND SYMPTOMS low-grade fever : malaise, loss of appetite, and muscle aches A high fever: chills, sweating, stiff joints, or back pain can indicate that acute illness has occurred DIAGNOSIS. thorough medical history and a physical exam are essential to diagnosis. Which contain 1- symptoms 2- valve replacement 3- bacterial or fungal infection(dental procedures)

Treatment: SBE is treated with antibiotics, but the most effective approach is prevention.

CARDIAC SURGERY Discharge Teaching: Activity Tolerance; No Bike Riding Until Sternotomy Healed Signs & Symptoms of Wound Infection Return to School in 2 Weeks Usually, No Further Cardiovascular Problems ALLOW THE CHILD TO LIVE A NORMAL AND ACTIVE LIFE!

Congestive Heart Failure (CHF) Cardiac Output (CO) Inadequate to Support Circulatory & Metabolic Needs Causes: volume overload, pressure overload, decreased contractility, high cardiac output demands Infant Tires During Feeding (OFTEN FIRST Indication of CHF) Symptoms Increase With Progressing Disease Cardiomegaly Occurs As Heart Attempts to Maintain Cardiac Output If Tachycardia Greater than 180-220 BPM; Ventricles Unable to Fill & CO Falls

CHF CHD Most Common Cause of CHF in Infants S/S: Tachycardia Diaphoresis, Tachypnea, Feeding problem, Crackles & Respiratory Distress; Edema, increase weight CXR Shows Large Heart. Echocardiogram is Diagnostic.

CHF Medical Management: Digoxin To Make Heart Work More Efficiently Lasix/Diuretics To Remove Excess Fluid Oxygen: Potent Vasodilator which decreases pulmonary vascular resistance. Rest, a neutral thermal environment, semi- Fowler position, cluster care to promote uninterrupted rest

CHF Nursing care Monitor physiologic functions: BP, HR, RR Prevent infection; Group care; Semi-Fowler position. Adequate Nutrition: Feeding Techniques: 45 Degree Angle; Rest Frequently. Promote Development: Play, Age Appropriate Toys, Physical Activities With Rest Periods Emotional Support: Prevent Hypoxia From Agitation or Distress; Consistency(suport) of Caregiver for Patient; Refer-Parent-to-Parent Support Groups.

RHEUMATIC FEVER Inflammatory Disease Following Initial Infection by Group A Beta Hemolytic Streptococci; Cause Changes in Heart, Joints, Skin & CNS. Diagnosis: ESR( erythrocyte segmentation rate), CRP(C- reactive protein), ASLO (anti-streptolysin O- titers) Treatment With Antibiotics To Treat Strep Infection Aspirin To Control Joint Pain & Inflammation Prevention is Best Treatment: Throat Culture & Treat With Antibiotics for 10 Days

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