The goal of this clinical trial is to learn if rivaroxaban works better than enoxaparin to prevent deep vein thrombosis (DVT) after emergency exploratory laparotomy in adults. It will also learn about the safety of rivaroxaban compared to enoxaparin. The main questions it aims to answer are: Does rivaroxaban lower the number of patients who develop DVT after exploratory laparotomy compared to enoxaparin? What medical problems or side effects do participants have when taking rivaroxaban versus enoxaparin? Researchers will compare rivaroxaban (an oral anticoagulant) to enoxaparin (a subcutaneous injection) to see which drug works better to prevent blood clots after surgery. Participants will: Take rivaroxaban 10 mg orally once daily for 7 days, or enoxaparin 40 mg subcutaneously once daily for 7 days after surgery Undergo duplex color Doppler ultrasound scans of the legs on day 5 and day 10 after surgery Be monitored for bleeding, complications, and other side effects