Question 1

What causes flail chest to develop?

Accepted Answer

Flail chest occurs when three or more adjacent ribs fracture in multiple places, creating an unstable chest wall section. Common causes include blunt trauma from motor vehicle accidents or steering wheel injuries, falls in elderly individuals with osteoporosis, and assaults with sharp objects. These traumatic events fracture ribs, costal cartilage, or sternum, destabilizing the thoracic cage.

Question 2

How does paradoxical breathing affect gas exchange in flail chest?

Accepted Answer

During inspiration, the flail segment moves inward, limiting air intake and reducing ventilation efficiency. During expiration, it moves outward, hindering exhalation. This paradoxical movement increases dead space—ventilated areas not participating in gas exchange—leading to compromised gas exchange and hypoxemia as oxygen delivery becomes inefficient.

Question 3

What are the primary clinical symptoms of flail chest?

Accepted Answer

Patients experience chest pain from fractures and wall movement, dyspnea from compromised lung expansion, hypoxemia with low blood oxygen, and tachypnea as the body compensates for reduced lung function. Cyanosis may develop due to poor oxygenation. These symptoms reflect the respiratory impairment caused by the unstable chest wall.

Question 4

What serious complications can develop from untreated flail chest?

Accepted Answer

Severe cases can cause pneumothorax when air accumulates in the pleural space due to chest wall instability. Crepitus occurs as fractured bone ends rub together. Poor tissue perfusion and metabolic acidosis result from reduced cardiac output, while atelectasis develops as lung tissue collapses, further compromising respiratory efforts and oxygenation.

Question 5

Why does the diaphragm's movement worsen flail chest symptoms?

Accepted Answer

During inspiration, the diaphragm moves downward, creating negative pressure that exacerbates the inward movement of the flail segment. This intensifies the paradoxical motion, reducing ventilation efficiency and limiting air intake. The negative pressure pulls the unstable segment inward rather than allowing normal chest wall expansion.

Question 6

How does flail chest impair respiratory function compared to normal breathing?

Accepted Answer

Normal breathing involves coordinated chest wall movement for efficient gas exchange. In flail chest, the unstable segment moves independently and paradoxically, disrupting this coordination. This causes dyspnea, tachypnea, increased dead space, and compromised gas exchange, forcing the body to work harder to maintain adequate oxygenation and ventilation.

Question 7

What role does chest wall instability play in flail chest pathophysiology?

Accepted Answer

Fractures of ribs, costal cartilage, or sternum create an unstable chest wall that cannot maintain normal structural integrity. This instability allows the detached flail segment to move independently during breathing, causing paradoxical movement that impairs respiratory function, reduces ventilation efficiency, and triggers compensatory mechanisms like tachypnea and increased metabolic demand.

חזה מרפרף I: מבוא

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