Chest injuries are common in patients with polytrauma and are responsible for approximate 25% of all trauma-related mortalities. Traumatic injuries to the thorax often result in the accumulation of blood within the pleural space (i.e. a hemothorax (HTX)). The management of HTX remains a clinical dilemma when the volume of blood is small to moderate and the patient is hemodynamically stable. Prior to the ubiquitous use of chest computed tomography (CT), diagnosing quantities of blood \<1000 mL was challenging (especially given inherent limitations in the standard chest radiograph (CXR)). With the widespread adoption of CT ''pan-scanning'' however, significantly more HTXs are being detected. The clinical significance and optimal treatment of these small to moderate HTXs remains unknown. Although HTXs are effectively managed with tube thoracostomy (TT) drainage of the pleural space (i.e. chest tube placement), this intervention is associated with numerous potential major complications, including iatrogenic injury, retained HTX, and empyema in up to 22% of patients. The East American Association of Trauma guidelines suggest that all HTXs should be considered for TT drainage. However, a prospective observational study suggested small to moderate HTXs could be absorbed without intervention. Classic studies from the 1960's also indicate that much larger quantities of blood can be reabsorbed without intervention as well. As a result, it is unclear if chest tubes are being over-utilized in patients who may not actually require them. Retrospective data from over 2,000 patients also suggests that many traumatic HTXs can be managed expectantly without TT drainage. Finally many small or occult HTXs (those not diagnosed by CXR, but later detected by CT scan) may also be safely observed, thus supporting the concept of expectant management (EM) for many HTXs with the goal of minimizing patient morbidity.

The Foothills Medical Centre recently reported a retrospective study including 635 patients with traumatic HTXs. Overall, 491 (66%) HTXs were drained while 258 (34%) were managed expectantly. Independent predictors of TT placement included concomitant ipsilateral flail chest or pneumothorax. It also became evident that clinical practice was not directly dependent on the specific size of the HTX. Although the adjusted odds of mortality were not significantly different between groups (OR 3.99; 95% CI 0.87-18.30; p = 0.08), TT was associated with a 47.14% (95% CI, 25.57-69.71%; p \< 0.01) adjusted increase in hospital length of stay. Empyemas (n = 29) also only occurred among TT patients. The authors concluded that expectant management of traumatic HTX was associated with a shorter length of hospital stay, no empyemas, and no increase in mortality. Although EM of small HTXs appears safe and optimal, these findings must be confirmed by a larger randomized controlled trial. The purpose of this study is therefore to conduct a randomized controlled study to compare patients with traumatic HTX managed by TT or EM. Characterization of those HTXs that require pleural drainage versus those that can be managed conservatively will be optimally defined. The results from this study will inform the care of future trauma patients who present with this common injury throughout the globe.