A 58-year-old man with a 20-year history of alcohol use disorder presents to the emergency department with hematemesis and melena. On examination, he is hemodynamically unstable (BP 90/60 mmHg, HR 118/min). Abdominal examination reveals a firm, enlarged liver and ascites. Upper endoscopy confirms actively bleeding esophageal varices. What is the most appropriate immediate next step in management?