Empyema occurring in the multiply traumatized patient

During an 11-month period 31 cases of nosocomial empyema were identified in 29 of 741 multiply traumatized patients who remained in our unit for more than 3 days. Nosocomial empyema was defined as purulent culture-positive material drained from the pleural space after five days' hospitalization. All patients had fever and leukocytosis. Possible risk factors included previous aspiration in five patients but none developing pneumonia, prior respiratory tract infection in nine but none with the same pathogen as their empyema, prior antibiotic use in over 50% of the patients, and severe head or chest injury in two thirds of the patients. Thirty-eight pathogens were recovered: S. aureus, 14; beta-streptococci, three; Pseudomonas, six; Klebsiella, two; Enterobacter, two; E. coli, two; other Gram-negative bacilli, six; and anaerobes, three. Fourteen infections were polymicrobic and bacteremia occurred in 42% of the patients. Of these 29 patients, 27 had chest tubes inserted for fluid in the pleural cavity before development of empyema; nine for hemo- or pneumothorax secondary to chest trauma, 11 for pneumothorax while on ventilators, and seven for unexplained sterile pleural effusion. If empyema complicated a prior hemothorax it was usually caused by Staphylococcus aureus and occurred about 10 days after draining blood from the pleural cavity. If empyema was a complication of pneumothorax or serothorax it was usually due to Gram-negative organisms colonizing the upper respiratory tract and occurred within 4 days of draining the fluid. Sixteen per cent of all patients who had chest tubes placed for fluid in their pleural cavity subsequently developed empyema.(ABSTRACT TRUNCATED AT 250 WORDS)