Page 1067 - Saunders Comprehensive Review For NCLEX-RN

Clubbing is symptomatic of chronic hypoxia. Peripheral

circulation is diminished, and oxygenation of vital organs and tissues is
compromised.
VI. Mixed Defects
A. Description
1. Fully saturated systemic blood flow mixes with the
desaturated blood flow, causing desaturation of the
systemic blood flow.
2. Pulmonary congestion occurs and cardiac output
decreases.

3. Signs of HF are present; symptoms vary with

the degree of desaturation.
B. Hypoplastic left heart syndrome
1. Underdevelopment of the left side of the heart occurs,
resulting in a hypoplastic left ventricle and aortic
atresia.

2. Mild cyanosis and signs of HF occur until the

ductus arteriosus closes; then progressive
deterioration with cyanosis and decreased cardiac
output are seen, leading to cardiovascular collapse.
3. The defect is fatal in the first few months of life
without intervention.
4. Surgical treatment
a. Surgical treatment is necessary;
transplantation in the newborn period
may be considered.
b. In the preoperative period, the newborn
requires mechanical ventilation and a
continuous infusion of prostaglandin
E to maintain ductal patency,
1
ensuring adequate systemic blood
flow.
C. Transposition of the great arteries or transposition of the great
vessels
1. The pulmonary artery leaves the left ventricle, and the
aorta exits from the right ventricle.
2. No communication exists between the systemic and
pulmonary circulation.

3. Infants with minimal communication are

severely cyanotic at birth.

4. Infants with large septal defects or a patent

ductus arteriosus may be less severely cyanotic but

1067