Flail chest

This code represents a flail chest, a life-threatening condition resulting from multiple rib fractures in two or more adjacent ribs, each broken in two or more places. This instability causes a segment of the chest wall to move paradoxically (inward on inspiration, outward on expiration) to the rest of the thoracic cage. It is typically caused by significant blunt force trauma to the chest.

Use this code when documentation clearly indicates a flail chest, often following severe trauma such as motor vehicle accidents or falls from height. The diagnosis should be supported by imaging studies (e.g., X-ray, CT scan) confirming the multiple rib fractures and clinical signs of paradoxical chest wall movement.

• Ensure documentation specifies "flail chest" and not just multiple rib fractures, as the latter may not meet the criteria for this specific diagnosis.
• Always sequence this code as a principal diagnosis when it is the primary reason for admission or encounter, or as a secondary diagnosis if it is a co-morbidity.
• Look for associated injuries, such as pneumothorax, hemothorax, or pulmonary contusion, and code them separately as they often accompany a flail chest.