Final answer:
The nurse will implement the order to insert a nasogastric (NG) tube and connect to suction first to help drain the blood from the stomach.
Step-by-step explanation:
The nurse will implement the order to insert a nasogastric (NG) tube and connect to suction first. The patient has vomited 1500 mL of bright red blood, indicating a significant gastrointestinal bleed. Inserting an NG tube and connecting it to suction will help drain the blood from the stomach, preventing further complications and providing immediate relief. This intervention takes priority over the other orders.