How does cardiac output reduce with a flail chest injury?

Cardiac output can reduce with a flail chest injury due to impaired mechanics of respiration and compromised pulmonary function. The instability of the rib cage leads to poor ventilation and inadequate oxygenation, which can cause hypoxia and reduced blood flow. Additionally, the pain associated with flail chest may decrease the patient's ability to take deep breaths, further diminishing lung capacity and resulting in decreased venous return to the heart. This combination of factors can lead to decreased stroke volume and overall cardiac output.