Flail chest
Flail chest is a marker of severe blunt thoracic trauma in which a contiguous segment of the chest wall loses continuity and moves independently of the rest of the thorax. It commonly causes respiratory compromise and frequently coexists with life‑threatening intrathoracic injuries; management therefore follows major‑trauma principles (NICE NG39).
Definition
- Two commonly used definitions:
- Traditional/textbook definition: fracture of ≥3 contiguous ribs in ≥2 places producing a free‑moving segment.
- NICE procedural definition (IPG361): at least two fractures per rib in ≥2 consecutive ribs - the definition used for selecting patients for surgical rib stabilisation.
- This handbook uses the NICE wording for procedural decision‑making while recognising variation in the literature (NICE IPG361).
Aetiology and mechanism
- Typically results from high‑energy blunt trauma: motor vehicle collisions, falls from height, crush injuries or heavy direct blows.
- Multiple adjacent ribs fractured in two places (or multiple fractures per rib) create a detached segment.
- Paradoxical motion (segment moves inward on inspiration and outward on expiration) reflects loss of chest wall continuity and altered intrathoracic pressure dynamics.
Associated injuries (frequently coexist; actively look for them)
- Pulmonary contusion - common; may progress over 24-72 hours causing worsening hypoxaemia and V/Q mismatch.
- Pneumothorax (including tension pneumothorax) and haemothorax.