Anatomy Msk · Year 1 · from Anatomy Msk
Case 2: Flail Chest with Respiratory Failure
Clinical Image
Source: Wikimedia Commons - Flail Chest - CC BY-SA 4.0
Case Presentation
A 52-year-old man is brought to the trauma center after being struck by a car as a pedestrian. He was found conscious but in significant respiratory distress at the scene. On arrival, he has labored breathing with a respiratory rate of 32 and oxygen saturation of 88% on high-flow oxygen. Examination reveals paradoxical motion of the right anterolateral chest wall - during inspiration, the affected segment moves inward while the rest of the chest expands outward. There is extensive ecchymosis and crepitus over the right chest. Breath sounds are diminished on the right. Chest radiograph reveals fractures of right ribs 3-7 in two places each (creating a free-floating segment), right-sided pneumothorax, and extensive pulmonary contusion. A right chest tube is placed with evacuation of air and 400 mL of blood. Despite this, he remains hypoxic with increasing work of breathing. Arterial blood gas shows PaO2 of 55 mmHg on 100% FiO2 and PaCO2 of 52 mmHg. He is intubated for respiratory failure and admitted to the surgical ICU. The underlying pulmonary contusion is the primary cause of his respiratory failure. He requires mechanical ventilation for 8 days with gradual improvement in lung compliance and gas exchange.
Key Learning Points
- Flail chest occurs when three or more consecutive ribs are fractured in two places, creating a free-floating segment
- Paradoxical motion: the flail segment moves inward during inspiration and outward during expiration
- Respiratory failure is primarily due to underlying pulmonary contusion, not the mechanical chest wall defect
- Positive pressure ventilation "internally splints" the flail segment and treats the associated lung injury
- Severe cases may benefit from surgical rib fixation to reduce ventilator days and improve outcomes