Predictors of conversion from thoracoscopic to open surgery in management of postpneumonic empyema

Background: Video-assisted thoracoscopic surgery (VATS) has an important role in management of pleural empyema. The objective of this study was to assess the predictors for conversion from VATS to open thoracotomy in an assumed stage II postpneumonic empyema. Methods: This prospective randomized study included 120 patients admitted to cardio-thoracic surgery department, Benha University, between 2011 and 2016. All cases were enrolled for thoracoscopic debridement for an assumed stage II postpneumonic empyema. If stage III empyema was diagnosed during thoracoscopy, conversion to thoracotomy became indicated. Predictors for conversion to thoracotomy were assessed in a univariate, a bivariate correlation and a multivariate analysis using several variables like age, sex, associated comorbidities, duration of symptoms, pleural fluid analysis, and pleural thickness measured by CT scan. Results: Out of 120 patients, thoracoscopic management was successful in 82 (68%) patients, while conversion to thoracotomy was done in 38 (32%) patients. Conversion to thoracotomy was higher in patients with long duration of symptoms (p < 0.001) with cutoff value at 18.1 days, increased pleural thickness (p < 0.001) with cutoff value at 3.95 mm, increased LDH with cutoff value at 1854 IU/L, and Gram-negative infection of pleural fluid (p < 0.001). Multivariate analysis identified that the duration of symptoms, gram-negative bacteria, LDH and pleural thickness were the significant predictors for conversion from VATS to thoracotomy. Conclusion: Predictive factors for conversion to thoracotomy in an assumed stage II postpneumonic empyema include long duration, Gram-negative bacterial infection, increased LDH, and increased pleural thickness