The Child with Cardiovascular Dysfunction

By : Basel AbdulQader RN, MSN, CCRN

Murad Sawalha RN, MSN, CCRN

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 lungsDuctus 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 placentaplacenta through the umbilical vein and enters the inferior vena cavainferior vena cava thought the Ductus Venosus .Ductus Venosus .This permits most of the highly oxygenated blood to go directly to the right atriumright atrium , bypassing the liver.

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

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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 .

Coronary circulation

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Deoxygenated blood returns from the heart and the arms through the superior vena cavasuperior 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 .

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Because pulmonary resistance is high , most of the blood passes into the distal aorta through the Ductus Ductus ArteriosusArteriosus, 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

Foramen Ovale: Opening Between Atria; Allows Blood to Bypass Lungs intrauterinely; Closes With Increased Left-Sided PressureDuctus 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 at birth

….. 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/minBlood pressure= 65/41 mmHgRespiratory rate= 30-60 breath/minTemperature= 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

CHDClassification of CHD: Acyanotic versus cyanotic

Acyanotic

Mixedblood flow

Pulmonary blood flow

Obstruction to Blood flow

from ventricles

PulmonaryBlood flow

Cyanotic

•Atrial septal defect (ASD)•Ventricularr septal defect (VSD)

•Coarctation of Aorta•Aortic stenosis

•Tetrology of Fallot•Tricuspid atresia

•TranspositionOf 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 andthe 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 fromthe left ventricle (higher pressure) to the right ventricle(lower pressure) causingleft-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

Cardiac catheterization lab

Selected cyanotic defect 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 VSD and 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. Pulmonary stenosis decreases blood flow to lungs making oxygen returns to Lt side of the heart.•S&S: cyanosis, clubbing fingers, poor growth. crying during or after feeding.•Surgical treatment: complete repair is required, open heart surgery& VSD closure.

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 NeedsCauses: volume overload, pressure overload, decreased contractility, high cardiac output demandsInfant Tires During Feeding (OFTEN FIRST Indication of CHF)Symptoms Increase With Progressing DiseaseCardiomegaly Occurs As Heart Attempts to Maintain Cardiac OutputIf Tachycardia Greater than 180-220 BPM; Ventricles Unable to Fill & CO Falls

CHFCHD Most Common Cause of CHF in InfantsS/S: Tachycardia Diaphoresis, Tachypnea,

Feeding problem, Crackles & Respiratory Distress; Edema, weight CXR Shows Large Heart. Echocardiogram is Diagnostic.

CHFMedical 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

CHFNursing 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 of Caregiver for Patient; Refer-Parent-to-Parent Support Groups.

ENDOCARDITIS

Patients With CHD, Prosthetic Cardiac Valve, Multiple Invasive Lines, etc May Be at Increased RiskStreptococcus viridan (most common)Insidious onset, low-grade intermittent fever, non-specific: malaise, myalgiasDefinitive Diagnosis: Blood CulturesIntravenous Antibiotics for 2-8 WeeksBedrest in Acute PhasePrevention is Best; Inform Dentist & MD for Prophylaxis PRIOR to Procedures

RHEUMATIC FEVERInflammatory 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 InfectionAspirin To Control Joint Pain & InflammationPrevention is BestTreatment: Throat Culture & Treat With Antibiotics for 10 Days