A flail chest occurs when segmental rib fractures allow a section of the thoracic cage to move independently. The negative inspiratory pressure created by the diaphragm is less effective since the flail segment paradoxically moves inward and interferes with ventilation. Pulmonary contusion, hemothorax, pneumothorax, and great vessel injuries frequently accompany a flail chest.
Flail Chest. Localized blunt trauma to the left anterior chest 4 cm inferior to the midclavicle, with resultant flail segment. Positive intrathoracic pressure (A) and negative intrathoracic pressure (B) demonstrate the paradoxical movement of the flail segment. (Photo contributor: Lawrence B. Stack, MD.)
Management and Disposition
Pain control and pulmonary hygiene are initial standard therapy. Mechanical ventilation is reserved for those with respiratory failure, not as a mechanism to stabilize the flail segment. Treatment of underlying pulmonary injuries and intensive care unit admission are required for these critically ill patients.
Intercostal nerve blocks may help provide adequate analgesia so that pain does not prevent the patient from ventilating adequately.
Continuous positive airway pressure (CPAP) with patient-controlled analgesia may be as effective as mechanical ventilation in patients with a flail chest.
Paradoxical movement of the flail segment is seen during the respiratory cycle in flail chest.
Flail Chest: Trauma Chest X-Ray. Fractures in two places of left ribs 3 and 4 result in a flail segment. Ribs 2 and 5 have single fractures. This is the chest x-ray of the patient in Fig. 7.6. (Photo contributor: Lawrence B. Stack, MD.)
Flail Chest: Chest Computed Tomography (CT) Scan. A flail segment is seen in the left anterior chest on an axial cut of this chest CT scan. A chest tube is seen in the left pleural space. Subcutaneous emphysema is seen in the area of the fractures and tracking posteriorly. This is the chest CT of the patient in Fig. 7.6. (Photo contributor: Lawrence B. Stack, MD.)
Video 07-01: Flail Chest
Subtle paradoxical right lateral chest wall movement is seen in this patient with a flail chest after bicycle handlebars hit him in the right lateral chest.