Background: The increased use of computed tomography (CT) results in higher occult hemothorax detection in blunt chest trauma. The indication for pleural decompression is not well defined. This research aims to study the overall factors determining pleural decompression. Methods: All blunt chest injury patients were retrospectively reviewed from the institutional trauma registry. Patients who underwent chest or whole-abdomen CT within 24 h were reviewed by a radiologist to identify initial occult hemothorax defined as a negative chest X-ray with the presence of hemothorax in the CT. The data included demographic data, mechanism of injury, complications, treatments, and characteristics of the hemothorax from the CT. Results: Six hundred and eighty-six blunt chest injury patients were reviewed over a period of 30 months. Eighty-one (24.9) patients had occult hemothorax. The mean time from injury to CT was 5.7 h. Most patients (87.6) were male. Most patients (70.2) suffered from traffic collisions and 84.4 had rib fractures. Pleural decompression was performed in 25 patients who had significantly thicker hemothorax (1.1 cm vs. 0.8 cm,P P P 1.1 cm was associated with increased risk of pleural decompression (odds ratio OR: 5.51, 95% confidence interval CI: 1.42 /21.42) and occult pneumothorax (OR: 6.93, 95% CI: 1.56/30.77). Conclusions: Drainage of occult hemothorax after blunt chest trauma was significantly associated with concomitant occult pneumothorax, lung contusion, and hemothorax thicker than 1.1 cm
