At what risk of empyema is empiric antibiotic therapy justified in tube thoracostomy for trauma?

Although empiric antibiotic treatment may prevent the development of empyema following tube thoracostomy for isolated chest trauma, such treatment has been questioned because empyema is an uncommon occurrence. Therefore, a threshold analysis was performed to determine the values of empyema risk and antibiotic efficacy above which empiric antibiotic therapy is warranted in tube thoracostomy for trauma. These thresholds and the 95% confidence bands above and below the threshold curve were estimated by Monte Carlo simulation. Comparison of published estimates of empyema risk and drug efficacy with the estimated threshold shows that they lie well within the region favoring empiric antibiotic treatment. For example. if antibiotics decrease the risk of empyema by a factor of four or greater, then any risk of empyema greater than 1-2% is great enough to justify treatment.