A patient with a history of Crohn's disease comes to the emergency room with rectal bleeding. Initial vital signs are BP 92/40, HR 124, RR 28, Temp 98.7°F (37.1°C), and Sa02 of 89% on room air. Which of the following orders should the nurse implement first?

A. Insert an 18 gauge intravenous catheter (IV): Establishing large-bore IV access is essential for fluid resuscitation and potential blood transfusion in a patient with suspected hypovolemic shock. However, the patient is currently hypoxic, and according to priority frameworks, oxygenation must be addressed before circulation. B. Administer oxygen at 2 L via nasal cannula: The patient has an oxygen saturation of 89%, indicating hypoxemia and impaired tissue oxygen delivery. Applying supplemental oxygen is the immediate priority to improve oxygenation and prevent further cellular hypoxia, especially in the setting of tachycardia and hypotension. C. Insert a 14 gauge nasogastric tube (NGT): A nasogastric tube may help determine the source of bleeding or decompress the stomach, but it does not address the patient’s immediate instability. It is not a priority over correcting hypoxia and stabilizing airway and breathing. D. Obtain a complete blood count: Laboratory evaluation is important to assess hemoglobin levels and severity of blood loss, but it does not provide immediate stabilization. In an unstable patient, interventions that directly improve oxygenation and perfusion take precedence over diagnostic measures.