You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A patient comes with hematemesis and melena. On the upper GI endoscopy, there were no significant findings. 2-days later the patient rebleeds. Next line of investigation is and explain in detail?
In case of intermittent upper GI bleeding for which no source has been found endoscopically or radiologically, laparotomy is done to see any missed common cause or angiodysplasia or for any obscure causes. SRB edition 5th page no .992