alterations in oxygenation 4
TRANSCRIPT
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Alterations in
Oxygenation
Neonate
Congenital Heart Defects
1. Defects with Increased Pulmonary Blood flow
b. Atrial Septal Defect
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b. Atrial Septal Defect- Septal defects are sometimes called a "hole" in
the heart. A defect between the heart's two upperchambers (the atria) is called an atrial septal defect
(ASD).
- the large defect between the atria, causes a largeamount of oxygen-rich (red) blood leaks from the
heart's left side back to the right side; this blood is
pumped back to the lungs, despite already having
been refreshed with oxygen.- this is inefficient, because already-oxygenated
blood displaces blood that needs oxygen. Many
people with this defect have few, if any, symptoms.
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- atrial septal defect is an abnormal
communication between the two atria,
allowing blood to shift from the left to the
right atrium (an acyanotic defect) because of
the stronger contraction of the left side of the
heart.- this causes an increase in the volume in
the right side of the heart and generally results
in ventricular hypertrophy and increasedpulmonary artery blood flow
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-fourth to the sixth week of gestation,
the common atrium is divided into two
chambers.
- the space between these two structures
is called the ostium primum (first hole); as
the first septum continues to grow, a hole
called the ostium secundum (second hole)
appears in its center, eventually it forms the
foramen ovale
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Incidence
- the ratio of atrial septal defect is 1:3; male
to female ratio
- it accounts 9.7% of the congenital heartdiseases or defects
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Altered Hemodynamics
- because left atrial pressure slightly
exceeds right atrial pressure, blood flows from
the left atrium, causing an increased flow of
oxygenated blood into the right side of the
heart- this results to right atrial and right
ventricular hypertrophy
- pulmonary vascular changes usuallyoccur only after several decades if the defect is
unrepaired
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Clinical Manifestations
- characteristic crescendo-decresendo
(harsh) type of systolic murmur over the
second to third intercostal space along the left
sternal border. The murmur is caused by
increased blood flow through the normal
pulmonic valve, not by the blood flow across
the defect
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Assessment and Diagnosis
*physical examination
- the most suggestive sign of atrial
septal defect is its characteristic murmur
*echocardiography
- echocardiography with color flow
Doppler will generally reveal the enlarged sideof the heart and the increased pulmonary
circulation.
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*cardiac catheterization
- cardiac catheterization would revealthe separation in the atrial septum and the
increased oxygen saturation in the right atrium.
*radiography
- Radiographic findings include right atrial
and ventricular hypertrophy.
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Therapeutic Management
- surgical closure of atrial septal defect is reservedfor moderate to large shunts and is done electively
between 1and 3 years of life. It is particularly importantthat atrial septal defect be repaired in girls, because itcan cause emboli during pregnancy.
*open heart surgery
- a cardiopulmonary bypass is done, and theedges of the opening are approximated and sutured.
- the surgery requires the use ofextracorporeal circulation
- if the defect is large, a Silastic or Dacronpatch may be sutured into place to occlude the space
- postoperative complication is unusual, andsurvival is greater than 99%.
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*interventional cardiac catheterization
- closure of an atrial septal defect
using cardiac catheterization with the use of
umbrella tipped catheter.
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Nursing Considerations
- pre-operative preparations
- ensure aseptic technique in the surgical
and invasive management
- post-operatively, carefully carefully
observe the child for arrhythmias in case
edema of the right atrium interferes with SA
node function, which ,may require pacemaker
implantation.
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Thank You