Emergency and Toxicologymiddle twist
A 74-year-old woman presents with sudden passage of a large volume of dark red blood per rectum. After two litres of intravenous crystalloid her blood pressure remains 88/58 mmHg, and blood continues to pass; she has no abdominal tenderness. She has received packed red cells and is being assessed for an active lower gastrointestinal source. Which one of the following should be undertaken next to localise the bleeding?