Failure of chest X-rays to diagnose pneumothoraces after blunt trauma.

We report four cases of occult pneumothorax in patients who had suffered blunt trauma. In each case supine chest X-rays failed to diagnose an anterior pneumothorax. Subsequent spiral computerised tomography scans of the chest showed anterior pneumothoraces in all cases. In two of the cases anterior pneumothoraces were present in spite of a chest drain having been placed in the pleural cavity. We recommend the insertion of anteriorly positioned chest drains to relieve pneumothoraces in severely injured trauma patients.