A 45 year old man, known to be chronically addicted to alcohol, presents in the emergency department and reports two episodes of vomiting fresh bright red blood in the previous 6 hours. Which is next appropriate step in management?

A 45 year old man, known to be chronically addicted to alcohol, presents in the emergency department and reports two episodes of vomiting fresh bright red blood in the previous 6 hours. He estimated the volume blood vomited at each bout to be more than 500mls. Clinical exam: the radial pulse 120/min, BP 90/60mmHg. There is no mass or tenderness in the epigastrium. The liver is palpable for 3 cm below the costal margin and not tender. The patient is not jaundiced. The physician resuscitates the patient with oxygen by face mask, rapid infusion of intravenous normal saline while he requests for haemoglobin level and whole blood for transfusion. Which is next appropriate step in management?