Chapter 41: Child with Cardiovascular disorder Flashcards
Changes in the heart of the newborn
First breath, lungs inflate, decrease in pulmonary vascular resistance, pulmonary artery pressure drops, R atrium pressure decrease. Blood flow to L heart increased pressure in L atrium, closure of foramen ovale. The decrease in pressure of the pulmonary artery leads to closure of the ductus arteriosus (between aorta and pulmonary artery). Ductus venosus (between L umbilical vein and IVC) closes because of lack of blood flow and vasoconstriction.
Heart rates
Infant 90-160
Toddler-Preschooler 80-125
School age 70-100
Adolescents 60-100
Bradycardia
infant<50
Normal BP
Infant 80/40
Toddler 80-100/64
School age 94-112/56-60
Adolescents 100-120/50-70
Digoxin
Give regular intervals about every 12 hours. One hour before or two hours after a meal. NOT WITH FOOD If it is missed and more than four hours have passed withhold the dose. Do not give a second dose if the child vomits. Monitor potassium levels which cause toxicity. Digitalizing the first dose is dividing it into several doses over 24 hours to reach maximum effect. Watch for prolonged PR interval, and decreased ventricular rate. S&S of toxicity: N&V, diarrhea, lethargy, bradycardia
Apical pulse for 60 seconds. Withhold if:
Infant <90
Clubbing
Clubbing of fingers and toes (usually after 1 year) indicated chronic hypoxia due to CHD. First sign is softening of the nail bed, rounding of the fingernails, shininess and thickening of ends.
Cardiomegaly
Abnormal heart enlargement. Often has a prominence of the precordial chest wall
Murmur evaluation
location relation to the heart cycle duration Intensity: Grade I soft and hard to hear, Grade II soft and easily heard Grade III loud without a thrill Grade IV loud with precordial thrill Grade V loud, precordial thrill, audible with stethoscope partially of chest Grade VI very loud, audible with the naked ear Quality: harsh, musical or rough; high, medium, or low pitch Variation with position: sit, lye, stand
Cardiac Catheterization info
Diagnostic: structural defects
Interventional: treatment to dilate occluded or stenotic structure of vessels or close some defects.
Electrophysiologic: electrodes ID abnormal rhythms and destroy sites of abnormal electrical condudtion.
R-side: femoral vein to the R atrium
L-side: into the aorta and heart via an ARTERY
Contrast material is injected into the heart and images taken.
Cardiac Catheterization nursing care
No iodine or shellfish allergy
No anticoagulants
Mark the location of pedal pulses for easy finding later
Inform they may feel heart racing, and warmth or stinging with contrast.
Complications: bleeding, low grade fever, loss of pulse in the extremity used for catheterization, development of arrhythmia. Leg will need to be straight for 4-8 hours with bed rest.
Post op: check the pressure dressing frequently. If bleeding occurs, apply pressure 1 inch above the site. I&O. Contrast is diuretic.
Instructions: Change pressure dressing day after, keep covered and do not get wet for several days. Report S&S infection. Compare extremities. take temp 1xday for 3 days, report if over 100.4. No bath for 3 days. No strenuous activity for 3 days. Tylenol or ibuprofen for pain
Categories of congenital heart defects
Disorders with decreased pulmonary bloodflow (cyanotic): tetralogy of fallot and tricuspid atresia
Disorders with increased pulmonary bloodflow (acyanotic): patent ductus arteriosus PDA, atrial septal defect, ventricular septal defect VSD
Obstructive disorders (acyanotic): coarctation of the aorta, aortic stenosis, pulmonary stenosis
Mixed disorders (cyanotic): transposition of the great vessels, total anomalous pulmonary venous return, truncus arteriosus, hypoplastic left heart syndrome
Disorders decreased pulmonary bloodflow
Pressure in the right side of the heart increases becoming greater than the left side. Deoxygenated blood mixes with the oxygenated blood on the left side and is pumped throughout circulation. This causes low oxygen saturation levels from 50 to 90%. The kidneys compensate for low oxygen, releasing EPO and increasing red blood cells called polycythemia. This can thicken the blood and increase the workload of the heart. Tetralogy of Fallot and tricuspid atresia
Tetralogy of fallot pathophysiology
Four defects:
- pulmonary stenosis: narrowing of the pulmonary valve and outflow tract, creating obstruction from R ventricle to the pulmonary artery. Decrease in blood flow to the lungs for O2 and amount returning from lungs. This increases pressure in the R-ventricle. Shunted thru VSD
- VSD ventricular septal defect allows O2 blood to mix with unO2 blood and is pumped thru
- Overriding aorta of the VSD: enlargement of the aortic valve so much that it appears to arise from the right and left ventricles rather than the correct left ventricle,
- R ventricular hypertrophy due to continued overuse while attempting to overcome the high pressure.
Dx occurs first few weeks life due to cyanosis and murmur. Most have a PDA (patent ductus arteriosus) at birth, decreasing the initial severity of cyanosis. Hypoxia is the primary problem
Tetralogy of Fallot treatment
Notice color changes associated with eating, activity, or crying. If cyanosis is to severe and persistent infant may come become unresponsive. As an infant gets older they can use specific postures such as bending the knees, assuming the fetal position to relieve a hypercyanotic spell. The walking child may squat periodically which helps increase pulmonary bloodflow by increasing systemic vascular resistance. In an infant, the nurse may put them in the knee chest position
May have loud harsh murmur, clubbing, decreased O2 sat
Labs: increased H&H, RBC; ECG, cardiac catheterization
Management: prostaglandin E1, dilate the ring around the ductus arteriosus, prophylactic antibiotics, propranolol to decrease myocardial irritability (prevent hypercyanotic spells), morphine to lower 02 demand, sodium bicarb to treat acidosis.
Surgical: palliative create a shunt from the aortic arch to the pulmonary artery to have blood going to lungs. Definitive is to repair stenosed valve, fix the septal defect, make sure aorta is only coming off the L ventricle.
Tricuspid atresia
The valve between the right atrium and the right ventricle fails to develop. There’s no opening to allow blood flow from the right atrium to the right ventricle and then through the pulmonary artery and lungs. Deoxygenated blood passes through the atrial septum thru a defect for a patent foramen ovale and into the L atrium. Deoxygenated blood mixes with oxygenated blood and travels through the lungs.
Infants will have cyanosis a few days later when the ductus arteriosus closes. They will have rapid respirations, difficulty feeding, cyanosis, poor sucking, crackles or wheezes, murmur, clubbing if older.
Disorders with increased pulmonary flow
Normally left-sided pressure is higher. With certain defects it will cause the right side of the heart pressure to rise. This causes a greater amount of blood to move through the heart. If the amount of blood flowing to the lungs is large, it could cause heart failure. It will cause R ventricle hypertrophy. Deoxygenated blood can mix with oxygenated blood.
Tachypnea will increase calorie use leading to feeding problems. tachycardia. Poor weight gain, decreased growth and development, sodium and fluid retention, increased risk for pulmonary infections, vasoconstriction decrease in pulmonary bloodflow. Pulmonary hypertension.. Oxygen is not helpful. It acts as a pulmonary dilator which will increase pulmonary bloodflow even more causing tachypnea, increasing lung fluid retention, and causing more problems. Early surgical correction is essential.
Atrial Septal Defect
A hole in the wall of the septum that divides the right atrium from the left atrium. There are three types based on location.
- Ostium primum ASD1: opening is at the lower portion of the septum
- Ostium secundum ASD2: opening is near the center of the septum
- Sinus venosus defect: opening is near the junction of the SVC and the R atrium
If small, 80% spontaneous closure in 18 months.
There is increased blood volume in the right atrium, increase blood flow to the lungs. It can cause pulmonary hypertension, heart failure, atrial arrhythmia, or stroke. Most children are asymptomatic.
Possible difficulty growing, hyperdynamic precordium, systolic ejection murmur, R ventricular heave
ECG, x-ray shows enlarged heart