Outcomes of management of retained hemothorax
Wing, Samuel Robert
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PURPOSE: Hemothorax, the collection of blood in the intrapleural space, commonly arises in patients suffering from thoracic trauma. Fluid collections in this space can compromise cardiac and respiratory function and if left untreated, can result in hypovolemic crisis. Fluid is often successfully drained via a tube thoracostomy, in which an intercostal drain is inserted into the pleural space. If residual blood remains, however, clotting may occur and result in a retained hemothorax (RH). Intrapleural administration of tissue plasminogen activator (tPA), a fibrinolytic drug typically utilized in ischemic stroke, has been shown to be both a safe and effective technique to hydrolyze RH clots and reduce the need for more invasive surgical interventions. The present study aims to evaluate the safety and efficacy of tPA administration at Boston Medical Center (BMC) and compare this data to those of prior studies. This study will also investigate if tPA as a definitive treatment for RH, could reduce the need for additional interventions such as surgical procedures including Video-Assisted Thoracoscopic Surgery (VATS) and/or invasive thoracaotomy. Hospital/intensive care unit (ICU) lengths of stay (LOS), ventilator time, and complication rates will be used to determine if tPA may allow for a significant decrease in patient cost and burden of care versus surgery. An analysis of patient demographics and injury data will be used to determine the individual factors that could be used to predict the success of tPA as a definitive treatment. Using evidence-based treatment protocols, the aforementioned data will be critically evaluated to determine the appropriate timing and sequential positioning of tPA administration in the treatment algorithm for retained hemothorax. METHODS: A single-institution retrospective chart review was conducted of patients treated for traumatic pneumohemothorax by the Department of Acute Care and Trauma Surgery at Boston Medical Center. A study on predictive factors of the development of retained hemothorax included all such patients that presented to the emergency department (ED) between May 2014 and June 2016. Demographic and injury characteristics were analyzed to determine if patients from specific groups or with specific injuries are more prone to develop RH. To evaluate the safety of intrapleural tissue plasminogen activator, the incidence of complications such as post-trauma infection and mortality were determined in patients that were administered tPA to resolve retained hemothorax between May 2014 through December 2016. Next, utilizing an expanded data set, the efficacy of tPA was evaluated by determining the percentage of cases in which tPA was able to definitively resolve RH. Secondary efficacy data including average hospital length of stay, average ICU length of stay, average mechanical ventilation time, and rate of readmission were compared between various interventions as well. Finally, to elucidate the risk factors for RH and independent predictors of tPA as a definitive treatment, demographic data including age, ethnicity, and gender as well as injury data including mechanism of injury, the presence or absence of multisystem trauma, and the presence or absence of specific injuries such as rib fracture, pulmonary contusion, or diaphragmic insult were collected. RESULTS: A statistically significant positive correlation was observed between the likelihood of developing RH and both abdominal alimentary tract and extremity injuries, indicating that these injuries may serve as predictive factors for RH development. In a study investigating the safety of intrapleural tPA, there was no statistically significant difference in post-trauma infection rates between individuals treated with tPA and those who were not. Additionally, tPA treatment was associated with a lower mortality rate. Efficacy studies revealed that tPA therapy was associated with a statistically significant decrease in mechanical ventilation time, as compared to surgical intervention, however, tPA carried a RH resolution rate of just 43% with one patient experiencing a major adverse systemic reaction to the drug. Finally, demographic and injury data were analyzed to determine predictive factors of tPA success, but no statistically significant relationships were observed between any of these characteristics and the outcome of tPA therapy. CONCLUSION: Intrapleural tPA is a safe and effective alternative to more invasive surgical procedures. The success rate of tPA therapy in the present study was less than previous studies have indicated, however, the potential decreased ventilation time is important for preventing ventilator associated pneumonia (VAP) and the high rate of mortality it carries. Although the success rate is lower than expected, tPA should still be considered in the RH treatment protocol, prior to surgery, to decrease required ventilation time and potentially prevent the need for more invasive interventions with higher costs, morbidity, mortality rates, and patient burden.