S38 Can we predict who will suffer a spontaneous pneumothorax after endobronchial lung volume reduction

Background Spontaneous pneumothorax (SP) is a recognized and potentially fatal complication of endobronchial lung volume reduction (EBLVR) in patients with severe emphysema. It has been suggested that prophylactic chest drainage in these patients may minimize this risk but this procedure may in itself increase morbidity. A selective approach to chest drainage would be beneficial thus an understanding of the risk factors may direct practice. Method In a consecutive series of 35 patients we have compared preoperative variables in those 13 patients who suffered post EBLVR SP with a contemporary control group of 22 who did not. We specifically analyzed the assessment of preoperative CT scans using the StratX software system. This system analyzes the severity of emphysema using voxel density. Results SP after EBLVR is associated with a higher emphysema score in the non-target lobe, which is assumed to be the source of the air leak. SP is also associated with anatomical homogeneity with a lower ratio of emphysema severity between target and non-target lobes. However, both groups had similar physiological heterogeneity. Conclusion SP appears to be more frequent in those with a discrepancy between heterogeneous perfusion and homogeneous emphysema scores. In these patients prophylactic chest drainage after EBLVR may be justified.