Alterations in Oxygenation 6

8/4/2019 Alterations in Oxygenation 6

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Alterations in Oxygenation

NeonateCongenital Heart Defects

1. Defects with Increased Pulmonary Blood flow

d. Atrioventricular Canal Defect

orEndocardial Cushion Defect


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d. Atrioventricular Canal Defect or

Endocardial Cushion Defect

- results form incomplete fusion of theendocardial cushion or the septum of the heartat the junction of the atria and ventricles

- usually there is a low atrial septal defectcontinuous with high ventricular septal defectand distortion of the mitral and tricuspid valves

- the blood flow is left to right, but blood mayflow between all four chambers


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- because of the failure of the septumto from between the atria and ventricles,conduction system is affected

- it leads to same manifestations asother septal defects (right ventricular

hypertrophy, increased pulmonary bloodflow)


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Altered Hemodynamics

- immediately after birth, while thenewborns pulmonary vascular resistance

is high, there is minimal shunting of blood

through the defect. Once this resistancefalls, left to right shunting occurs andpulmonary blood flow increases

- the resultant pulmonary vascularengorgement predisposes development ofcongestive heart failure


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Clinical Manifestations

- at birth signs and symptoms areminimal except during crying or onexertion, when cyanosis occurs

- if a complete atrioventriculoar canaldefect is present, caynosis will be moresevere

- murmurs characteristic of an atrialseptal dfect or ventricular septal dfect maybe found.


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Assessment and Diagnosis

*electrocardiography

- may reveal first degree heart block asimpulse conduction is halted before the AV node

*echocardiography

- will confirm the diagnosis, revealingabsence of the atrioventricular septum

*cardiac catheterization- findings are characteristic of a left to

right shunt and indicate the presence andlocation of septal defects


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Therapeutic Management

*open heart surgery- surgery may involve a valve

repair (valvuloplasty) as well as septalrepair because these defects are too largeto close spontaneously

- operative mortality depends onthe severity of the defect and the age ofthe child at the time of surgery and variesfrom 10% to 35%


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Nursing Considerations

- pre-operative preparations- ensure aseptic technique in the

surgical and invasive management

- post-operatively observe for thefollowing: bleeding, heart block,arrhythmias and congestive heart failure

- these patients are at risk for bacterialendocarditis and require antibioticprophylaxis


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Thank You

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Alterations in Oxygenation 6