Preoperative predictors of conversion in thoracoscopic surgery for pleural empyema

Thoracoscopy is an effective treatment method for pleural empyema; however, it is still not well defined as to which patient subgroups could benefit from it the most. The aim of the study was to identify preoperative factors that could facilitate selecting appropriate surgical intervention and to evaluate early postoperative period.

Seventy-one patients were prospectively included in the study, which was conducted from January 2011 to June 2014. Thoracoscopic surgery for Stage II/III pleural empyema was performed in all patients. Thoracoscopy failed in 18 (25.4%) patients, requiring conversion to thoracotomy. The preoperative factors that could possibly predict conversion were analysed.

Obliterated pleural space (12 patients) and failure to achieve lung re-expansion (6 patients) were the main reasons for conversion. Multivariable logistic regression analysis demonstrated that each day of illness [odds ratio 1.1 (95% confidence interval 1.0-1.2], P  = 0.004] and frank pus [odds ratio 4.4 (95% confidence interval 1.2-15.3), P  = 0.021] were independent predictors of conversion. Using receiver-operating characteristic analysis, it was determined that the duration of illness had a high predictive value for conversion [area under the curve 0.8 (95% confidence interval 0.7-0.9), P  < 0.001]. The cut-off value for duration of illness was 16 days (sensitivity 94.4%, specificity 54.7%). The conversion group had a significantly greater need for postoperative intensive care unit stay ( P  = 0.022) but a lower rate of reoperations ( P  = 0.105).

Duration of illness and frank pus discovered during thoracocentesis can help in selecting the patient for appropriate intervention. Earlier surgery for pleural empyema can reduce the rate of conversion and reoperation.