In cases of flail chest, what mechanical issue occurs upon inspiration?

In cases of flail chest, the primary mechanical issue during inspiration is paradoxical movement of the affected segments of the rib cage. Flail chest occurs when multiple adjacent ribs are fractured in two or more places, leading to a segment of the rib cage that becomes separated from the rest of the thoracic structure.

During inspiration, instead of the flail segment moving outward and expanding the chest cavity as it should, it is sucked inward due to negative pressure created by the diaphragm and intercostal muscles. This inward movement during inhalation can significantly impair ventilation and reduce the effectiveness of the respiratory efforts. The flail segment can also cause instability in the chest wall and disrupt normal respiratory mechanics, leading to compromised ventilation and gas exchange.

Understanding this paradoxical movement is crucial in the management of flail chest, as it highlights the need for supportive care, pain management, and potential surgical interventions to stabilize the chest wall and restore normal respiratory function.