What causes post-traumatic empyema?

Background: Empyema post chest trauma is a morbid condition requiring operative intervention (thoracotomy and decortication). It is hypothesized that patients who have a complicated initial pleural drainage procedure are at increased risk of developing an empyema.

Methods: All patients who underwent operative decortication for post-traumatic empyema over a 24 month period (July 2003 to June 2005) were included in the study. Data were collected on demographics, intercostal catheter (ICC) insertion, prehospital chest decompression and associated injuries. A matched group of patients who had ICC inserted for chest trauma and did not develop an empyema were used as controls.

Results: Fourteen patients had decortications for post-traumatic empyema. Two of three pneumocaths and one ICC were placed within the lung. Five other patients had multiple 'attempts' at ICC insertion. Only two patients had a single uncomplicated ICC inserted. The empyema and control group were well matched in terms of age (mean age 40 years in each group, P = 0.83), injury severity score (36.4 vs 35.3, P = 0.85) and presence of chest, abdominal and multi-system injury. The empyema group had significantly longer median hospital stay (12.8 vs 28.7 days, P = 0.05). The control group had less initial ICC inserted (median of 1.0 vs 2.0, P = 0.02). Only one patient had a complicated ICC insertion, and two uncomplicated pneumocaths were placed.

Conclusion: Patients with complex chest injuries in whom difficulties in initial pleural drainage are encountered are at increased risk of developing a post-traumatic empyema and have a prolonged hospital stay.