Clinical Research Directory

Inclusion Criteria: 1. Adult trauma patients aged 18 to 65 years 2. Significant bleeding from traumatic events including 1. Exsanguinous external bleeding (500 ml or more), or 2. Evidence of internal bleeding (e.g., FAST positive, hemothorax, or bleeding seen on CT scan) 3. Hemorrhagic shock is defined as: 1. Hypotensive event suspected from hemorrhagic shock, characterized by * Systolic blood pressure less than 90 mmHg, * Mean arterial pressure less than 65 mmHg, or * A decrease in blood pressure from baseline more than 30 mmHg (as recorded in the trauma bay, resuscitation room of the emergency department at Ramathibodi Hospital, trauma unit at Siriraj Hospital, or trauma ward/ ICU) OR 2. Signs of shock, including: * Capillary refill time greater than 2 seconds, * Base excess less than -6 mEq/L, * Lactate level greater than 2 mmol/L) Exclusion Criteria: 1. Prehospital cardiopulmonary resuscitation or cardiopulmonary resuscitation at the trauma bay. 2. Persistent shock for more than 12 hours prior to randomization. 3. Severe traumatic brain injury with Glasgow Coma Scale (GCS) score less than 9 (GCS 3-8) 4. Traumatic limb injury with acute limb ischemia 5. A history of limb ischemia, chronic heart disease, chronic lung disease, or chronic renal disease 6. Pregnant patients 7. Documented "Do Not Resuscitate" (DNR) order or who declined life-sustaining intervention before randomization 8. Allergic to norepinephrine or contraindications for its use (e.g., peripheral vascular thrombosis, mesenteric thrombosis, and fatal tachyarrhythmia) 9. Current use of ergotamine, monoamine oxidase inhibitors (MAOIs), or tricyclic antidepressants (TCAs) 10. Prior vasopressor administration before randomization. 11. Weight less than 30 kilograms (Extremely low body weight may increases the risk of weight-based dosing issues)