The finding of S pneumoniae has been described in from 2% to 21% of cases in other series of empyema. In our series, it was found within the expected range (9%). Among Gram-negative bacilli, H influenzae was isolated in only 3% of our patients, whereas Pseudomona species was more frequent (9%). The percentage of sterile fluids in our series (17%) was greater than that reported by other authors (7%). This finding was probably due to the early administration of broad-spectrum antibiotics.
Bacteremia was detected in 52% of the cases and, once more, S aureus was the bacteria most frequently encountered (29%). In 53% of these episodes, the pathogens isolated were different from those isolated in pleural effusions. Multiple organisms were cultured in 56% of our patients (average, 3.38±2 per patient) and only in three cases (13%) were all the cultures negative.
The length of hospitalization, duration of pleural drainage, and the empyemas associated with BP were similar to those reported in other series of empyema in HIV-seronegative patients. However, the most notable difference between our series and other studies was that none of the patients needed surgical procedures to control the infection. None of them, once closed chest drainage was instituted, required other types of intervention, and no adverse secondary reactions to intrapleural administration of SK were noted in any patient. The greater success rate in our series with respect to other authors could be due to the immediate onset of pleural drainage (including nonpurulent fluid with a low pH), early use of fibrinolytics, and the absence of long-standing pleuropulmonary alterations in our patients. Thoracoscopy was not used in any of our patients. Several investigators have reported a successful lysis of adhesions and a debridement of empyema cavities via thoracoscopy. A success rate of only 60%, together with the inability to perform an adequate decortication by thoracoscopy, limits the use of this technique in some cases. However, it appears to be a reasonable approach to try to minimize the morbidity and mortality associated with thoracic empyema.