Intrapleural thrombolytic treatment with urokinase for retained hemothorax is effective and safe. However, previous study was limited in prospective observation study without control group.

We will recruit 32 patients in this study. The patients with retained hemothorax will be randomly divided into the urokinase group and the placebo group. In the urokinase group, urokinase 100,000 IU in 100 mL NaCl will be injected into the intrapleural space. We will record the daily drainage amount and evaluate the therapeutic effect by the chest X-ray. The therapeutic effect, safety, hospital stay, and medical cost between the two groups will be compared. This study will be done in four medical centers in northern Taiwan.

Inclusion Criteria:

1. Retained hemothorax: it is defined as chest X-ray revealing obvious blood clot in pleural cavity after tube thoracostomy drainage for 3 days. The chest tubes are in good location and have no obstruction. The physician thinks the blood clot is difficult to drain.
2. Age: full 18 year-old

Exclusion Criteria:

1. Pregnancy
2. Active bleeding
3. Coagulopathy, e.g. congenital or acquired coagulation abnormality, platelet count less than 100,000 /μL, international normalized ratio (INR) more than 1.5, or partial thromboplastin time, PTT, more than 50 seconds after treatment.
4. Cerebrovascular accident within 30 days
5. History of intracranial tumor or vascular abnormality
6. Have received thoracic surgery
7. Have received pleurodesis
8. Wish to receive thoracoscopic surgery for hematoma evacuation directly
9. Allergy to urokinase
10. Sepsis
11. Shock
12. People who are less than 18 years of age, prisoners, aborigines.