رباعية فالو

Definition

Tetralogy of Fallot is the commonest cyanotic heart defect, made of four parts:

• Ventricular septal defect
• Right ventricular outflow (pulmonary) stenosis
• Overriding aorta
• Right ventricular hypertrophy

Mechanism

The pulmonary obstruction pushes some deoxygenated blood right to left across the VSD into the aorta, causing cyanosis.

Symptoms

• Cyanosis that worsens with crying and feeding
• Tet spells: sudden deep cyanosis and fast breathing, possibly loss of consciousness
• Older children squat to relieve symptoms
• A systolic murmur and, over time, clubbing

Diagnosis

Echocardiography; chest X-ray shows a boot-shaped heart.

Managing a tet spell

• Knee-chest position
• Oxygen and calming the child
• Morphine, IV fluids and other drugs as ordered

Definitive treatment

Complete surgical repair, usually in the first year.

Nursing care

• Keep the child calm and avoid prolonged crying
• Good hydration, because dehydration raises clot risk with a high haemoglobin
• Teach parents how to manage a spell

Exam point

Squatting and the knee-chest position raise systemic vascular resistance, reducing right-to-left shunting and increasing pulmonary blood flow.