LONG-TERM ANTIMICROBIAL PROPHYLAXIS IN LUNG-CANCER SURGERY - CORRELATION BETWEEN MICROBIOLOGICAL FINDINGS AND EMPYEMA DEVELOPMENT

This study was planned in order to determine the value of antimicrobia l prophylaxis in preventing post-operative empyema in patients undergo ing lung cancer surgery. Two-hundred consecutive subjects operated upo n for lung cancer received teicoplanin and aztreonam, starting at the induction of anesthesia and lasting until removal of the pleural drain s. Cultures for aerobic and anaerobic bacteria were taken from: (1) th e bronchus at the time of surgical division; (2) the pleural space bef ore closure of the chest; (3) the pleural fluid during the postoperati ve period; and (4) the tips of chest drains at the time of their remov al. In the 200 patients receiving antibiotic prophylaxis, the number o f post-operative empyemas (1%) was lower than that (7.5%) found in 53 comparable patients who were previously treated with placebo. In the ' placebo group', empyema was due to gram-positive bacteria, while in th e 'prophylaxis group', it was caused by Gram-negative bacteria (Pseudo monas aeruginosa). A significant (P < 0.05) correlation between infect ed bronchial secretions, pleural space contamination at surgery, conta mination of chest fluid and drains during the post-operative period, a nd empyema development was demonstrated, In conclusion, antibiotic pro phylaxis, while being effective in preventing post-operative empyema, may induce the colonization of the respiratory tract with highly resis tant gram-negative bacteria.