Thursday, February 5, 2009

Pediatric Nursing Cardiac Diseases


  • Lecture notes on Pediatric Cardiac Diseases

    Health History
    Family history of defects / early cardiac disease / siblings with defects
    Maternal history of stillborns or miscarriages
    Congenital anomalies / genetic anomalies / fetal alcohol syndrome / Down Syndrome and Turner Syndrome
    Maternal exposure to rubella



    Present Health History
    Heart murmur
    Tires while eating
    Low weight for height
    Sweats while eating (diaphoretic)
    Cyanosis, worsens with feeding or activity level
    Irritable weak cry


    Health History
    In the older child additional symptoms may include:
    Chest pain
    Decreased activity level
    Syncope
    Slight of build


    Heart Sounds
    Use both the bell (for low frequency) and the diaphragm (for high frequency)
    Quality: distinct S1 and S2
    Rate matches radial pulse
    Intensity
    Rhythm



    Heart Sounds
    Heart sounds should be crisp and distinct in children.
    S1 is the first heart sound, produced by closure of the tricuspid and mitral valves when ventricular contraction begins.
    S2 is produced by the closure of the aortic and pulmonic valves.



    Heart Murmurs
    These sounds are produced by blood passing through a defective valve, great vessel, or other heart structure.
    Murmurs are classified by: intensity, location, radiation, timing, and quality.



    Knee-chest Position (TET spells)

    Children with cyanotic heart
    defect squat (assumes a knee-chest position) to relieve
    cyanotic spells. Some times called “tet” spells.
    Nurses put infant in knee-chest
    position. This positioning decreases blood return from the lower extremities.



    First Breath
    Pulmonary alveoli open up
    Pressure in pulmonary tissues decreases
    Blood from the right heart rushes to fill the alveolar capillaries
    Pressure in right side of heart decreases
    Pressure in left side of heart increases
    Pressure increases in aorta



    Treatment Modalities
    Palliative procedures
    Pulmonary artery banding
    Shunts
    Corrective procedures


    Diagnostic Test
    Chest x-ray to define silhouette of the heart.
    Heart size, shape, pulmonary markings, and cardiomegaly.
    Electrocardiogram to define electrical activity of the heart.
    Echo-cardiogram to visualize anatomic structures.
    Cardiac Conduction

    Cardiac Catheterization
    An invasive test to diagnose or treat cardiac defects.
    Visualizes heart and vessels.
    Measures oxygen saturation of chambers.
    Measures intra-cardiac pressures.
    Determines muscle function and pumping action of the heart.

    Pre-cardiac Catheterization
    Assess vital signs with blood pressure.
    Hemoglobin and hematocrit
    Pedal pulses
    NPO
    Hold digoxin
    IV if child is polycythemic

    Post-cardiac Catheterization
    Vital sign, with apical pulse, and blood pressure q 15 minutes for first hour.
    Apical pulse for 1 minute to check for bradycardia or dysrhythmias.

    Toxicity to Dye
    Watch for signs of toxicity to the dye used during the procedure.
    Increased temperature
    Urticaria
    Wheezing
    Edema
    Dyspnea
    Headache

    Home Care Instructions
    Keep dressing in place for 24 hours.
    Keep site dry and clean.
    Observe site for redness, swelling, drainage, or bleeding.
    Check temperature.
    Avoid strenuous exercise.
    Acetaminophen for pain.
    Keep follow-up appointment
    Pre-procedure medications as ordered.
    Post-cardiac Catheterization
    Assess pulses below the cath site.
    Record quality and symmetry of pulses.
    Assess temperature and color of affected extremity.
    Check dressing for bleeding or hematoma formation.

    Right to Left Shunts
    Occurs when pressure in the right side of the heart is greater than the left side of the heart.
    Resistance of the lungs in abnormally high
    Pulmonary artery is restricted
    Deoxygenated blood from the right side shunts to the left side
    Hole in septum + obstructive lesion =
    Deoxygenated blood from the right side of the heart shunts to the left side of the heart and out into the body.

    Clinical Manifestations
    Hypoxemia = the result of decreased tissue oxygenation.
    Polycythemia = increased red blood cell production due to the body’s attempt to compensate for the hypoxemia.
    Increase viscosity of the blood = heart has to pump harder.
    Potential Complications
    Thrombus formation due to sluggish circulation.
    Brain abscess or stroke due to the un-oxygenated blood bypassing the filtering system of the lungs.

    Left to Right Shunt
    Pressures on the left side of the heart are normally higher than the pressures in the right side of the heart. If there is an abnormal opening in the septum between the right and left sides, blood flows from left to the right.

    Clinical Manifestations
    The infant is not cyanotic.
    Tachycardia due to pushing increased blood volume.
    Cardiomegaly due to increased workload of the heart.
    Dyspnea and pulmonary edema due to the lungs receiving blood under high pressure from the right ventricle.
    Increased number of respiratory infections due to blood pooling in the the lungs promoting bacterial growth.

    Congestive Heart Failure
    Major manifestation of cardiac disease.
    Under 1 year of age due to congenital anomaly.
    Over 1 year with no congenital anomaly may be due to acquired heart disease.
    Cardinal Signs of CHF
    Tachycardia
    Cardiomegaly
    Tachypnea
    Hepatomegaly

    Digoxin Therapy

    nDigoxin increases the force of the myocardial contraction.
    qTake an apical pulse with a stethoscope for 1 full minute before every dose of digoxin. If bradycardia is detected.
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* Call physician before administering the drug.

Patent Ductus Arteriosus
PDA
Incidence 10%
One of the most common benign defects
Ductus normally closes within hours of birth
Connection between the pulmonary artery (low pressure) and aorta (high pressure)
High risk for pulmonary hypertension

Diagnosis and Treatment
Diagnosis: heart murmur may be heard in the pulmonary valve area because the heart is forcing an unusually large amount of blood through a normal sized valve.
Echocardiogram is the primary method used to diagnose the defect – it can show the hole and its size and any enlargement of the right atrium and ventricle in response to the extra work they are doing.


Treatment
Surgical closure of the atrial septal defect
After closure in childhood the heart size will return to normal over a period of four to six months.
No restrictions to physical activity post closure


Ventricular Septal Defect
VSD
30% of defects
Opening in the ventricular septum
Left-to-right shunt
Right ventricular hypertrophy
Deficient systemic blood flow
VSD
Small holes generally are asymptomatic
Medium to moderate holes will cause problems when the pressure in the right side of the heart decreases and blood will start to flow to the path of least resistance (from the left ventricle through the VSD to the right ventricle and into the lungs)
This will generally lead to CHF


Diagnosis and Treatment
Diagnosis – heart murmur – clinical pearl a louder murmur may indicate a smaller hole due to the force that is needed for the blood to get through the hole.
Electrocardiogram – to see if there is a strain on the heart
Chest x-ray – size of heart
Echocardiogram – shows size of the hole and size of heart chambers


Treatment VSD
CHF: diuretics of help get rid of extra fluid in the lungs
Digoxin if additional force needed to squeeze the heart
FTT or failure to grow may need higher calorie concentration
Will need prophylactic antibiotics before dental procedures if defect is not repaired


Surgical Repair
Over a period of years the vessels in the lungs will develop thicker walls – the pressure in the lungs will increase and pulmonary vascular disease
If pressure in the lungs becomes too high the un-oxygenated blood with cross over to the left side of the heart and un-oxygenated blood with enter the circulatory system.
If the large VSD is repaired these changes will not occur.


Coarctation of Aorta
COA
7 % of defects
Congenital narrowing of the descending aorta
80% have aortic-valve anomalies
Difference in BP in arms and legs (severe obstruction)+


Diagnosis and Treatment
In 50% the narrowing is not severe enough to cause symptoms in the first days of life.
When the PDA closes a higher resistance develops and heart failure can develop.
Pulses in the groin and leg will be diminished
Echocardiogram will show the defect in the aorta


Treatment
Prostaglandin may given to keep the PDA open to reduce the pressure changes
The most common repair is resection of the narrowed area with re-anastomosis of the two ends
Surgical complications – kidney damage due to clamping off of blood flow during surgery
High blood pressure post surgery – may need to be on antihypertensives
Antibiotic prophylactic need due to possible aortic valve abnormalities.


Pulmonary Stenosis
PS
7% of defects
Obstruction of blood flow from right ventricle
Hypertrophy of right ventricle
If severe cyanosis due to right-to-left shunt


Pulmonary Valvar Stenosis
In pulmonary valvar stenosis the pulmonary valve leads to narrowing and obstruction between the right ventricle and the pulmonary artery.
Thickened tissue become less pliable and increases the obstruction
Right ventricle must work harder to eject blood into the pulmonary artery.


Diagnosis and Treatment
Diagnosis: heart murmur is heard – clicking sound when the thickened valve snaps to an open position.
Electrocardiogram would be normal
Echocardiogram most important non-invasive test to detect and evaluate pulmonary stenosis
Cardiac Catheterization – to measure pressures and measure the stenosis


Treatment
Cardiac Catheterization to dilate the valve and open up the obstruction.
Open- heart procedure would only needed for more complex valve anomaly.


Tetralogy of Fallot (TOF)
6% of defects
Most common cardiac malformation responsible for cyanosis in a child over 1 year


TOF
Four Components
VSD
Pulmonary stenosis – narrowing of pulmonary valve
Overriding of the aorta – aortic valve is enlarged and appears to arise from both the left and right ventricles instead of the left ventricle
Hypertrophy of right ventricle – thickening of the muscular walls because of the right ventricle pumping at high pressure


Clinical Manifestations
Dependent on degree of right ventricular outflow obstruction.
Right-to-left shunt
Clubbing of digits
"tet" spells - treated by flexing knees forward and upward
Severe irritability due to low oxygen levels


Diagnosis
Cyanosis
Oxygen will have little effect on the cyanosis
Loud heart murmur
Echocardiogram – demonstrates the four defects characteristic of tetralogy


Treatment
If oxygen levels are extremely low prostaglandins may be administered IV to keep the PDA open
Complete repair is done when the infant is about 6 months of age
Correction includes
Closure of the VSD with dacron patch
The narrowed pulmonary valve is enlarged
Coronary arteries will be repaired
Hypertrophy of right heart should remodel within a few months when pressure in right side is reduced


Long Term Outcomes
Leaky pulmonary valve that can lead to pulmonary insufficiency
Arrhythmias after surgery
Heart block – occasionally a pacemaker is necessary
Periodic echocardiogram and exercise stress test or Holter evaluation


Aortic Stenosis
6% of defects
Aortic valve: has two rather than three leaflets. Leaflets are thickened or fused.
Obstruction of blood flow from left ventricle
Mild symptoms: dizziness, syncope, angina, fatigue
30% incidence of sudden death


Aortic Stenosis
Causes obstruction to blood flow between the left ventricle and aorta.
Most common form is obstruction of the valve itself
When the aortic valve does not open properly the left ventricle must work harder to eject blood into the aorta.
Left ventricular muscle becomes hypertrophied.


Diagnosis
Heart murmur or AS is a turbulent noise caused by ejection of blood through the obstructed valve.
Electrocardiogram is usually normal
Echocardiogram will show the obstruction and rule out other heart anomalies
Exercise stress test – provides information on impact of the stenosis on heart function


Treatment
Cardiac catheterization – balloon dilation of the narrowed valve.
Surgical valvotomy if the closed procedure does not work – often done when patient is older when severe calcium deposits further obstruct the valve.
Recurrent valve obstruction is a complication and if valve replacement is done too early the child may outgrow the valve.
Antibiotic prophylaxis especially if valve replacement


Hypoplastic Left Heart
One of the most complex defects seen in the newborn and the most challenging of all the congenital defects
All the structures on the left side of the heart are severely underdeveloped.
Mitral and aortic valves are either completely closed or are very small – left ventricle is tiny – aorta is small and often only a few millimeters in diameter


HLH
Life threatening shock develops when the ductus arteriosis closes
Low oxygen saturations – will not increase with oxygen administration
Pulses will be weak in all extremities
Plan to deliver infant in a hospital capable of providing the aggressive treatment needed


Treatment
Three staged procedure to reconfigure the cardiovascular system
Norwood – right ventricle becomes the systemic ventricle pumping blood to the body
Glenn done at 3-6 months
Fontan done at 2 -3 years of age


Long Term Complications
Easily tiring when participating in sports or other exercises
Formation of blood clots – heparin or Coumadin use
Heart arrhythmias – pace maker
Cardiac failure


Bacterial Endocarditis
Infection of endocardial surface of the heart
History of CHD, Kawasaki Disease, Rheumatic Fever, or prosthetic valves are more susceptible to infection
Prophylactic antibiotics with dental care, throat, intestinal, urinary or vaginal infections or surgery.


Kawasaki Disease
Acute-self limiting disease
Generalized vasculitis
Peak incidence 6 months to 2 years
More common in males and Japanese

http://www.aafp.org/afp/990600ap/3093.html


Clinical Manifestations
High fever
Conjunctivitis
Strawberry tongue
Edema of hands and feed
Reddening of palms and soles
Lymph node swelling


Blood Values
Elevated WBC
Elevated ESR
Elevated platelets


Management
Intravenous gamma globulin
High dose of ASA while in hospital
Low dose ASA upon discharge
Base-line echocardiogram to assess coronary artery status