Page 1065 - Saunders Comprehensive Review For NCLEX-RN

1. Obstructed pulmonary blood flow and an anatomical
defect (ASD or VSD) between the right and left sides
of the heart are present.
2. Pressure on the right side of the heart increases,
exceeding pressure on the left side, which allows
desaturated blood to shunt right to left, causing
desaturation in the left side of the heart and in the
systemic circulation.
3. Typically hypoxemia and cyanosis appear.
B. Tetralogy of Fallot
1. Tetralogy of Fallot includes 4 defects—VSD,

pulmonary stenosis, overriding aorta, and right
ventricular hypertrophy.
2. If pulmonary vascular resistance is higher than
systemic resistance, the shunt is from right to left; if
systemic resistance is higher than pulmonary
resistance, the shunt is from left to right.
3. Infants
a. An infant may be acutely cyanotic at
birth or may have mild cyanosis that
progresses over the first year of life as
the pulmonic stenosis worsens.
b. A characteristic murmur is present.

c. Acute episodes of cyanosis and

hypoxia (hypercyanotic spells), called
blue spells or tet spells, occur when the
infant’s oxygen requirements exceed
the blood supply, such as during
periods of crying, feeding, or
defecating (see Priority Nursing
Actions).

Priority Nursing Actions

Hypercyanotic Spell Occurring in an Infant
1. Place the infant in a knee-chest position.
2. Administer 100% oxygen.
3. Administer morphine sulfate.
4. Administer fluids intravenously.
5. Document occurrence, actions taken, and the
infant’s response.

Reference

McKinney et al. (2018), p. 1088.

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