What is the primary purpose of using a tourniquet in emergency situations?

The primary purpose of using a tourniquet in emergency situations is to halt severe bleeding. Tourniquets are specifically designed to apply pressure to a limb in order to constrict blood flow and control life-threatening hemorrhage, particularly in circumstances such as traumatic injuries or when direct pressure and other measures are insufficient. By stopping the blood flow to the affected area, a tourniquet helps prevent further blood loss and can be crucial in saving a person's life.

In scenarios where severe bleeding occurs, immediate intervention is necessary to prevent shock or death from blood loss. The application of a tourniquet is a critical skill for emergency responders, enabling them to manage urgent situations effectively until advanced medical help can be provided. The other options—promoting blood circulation, reducing swelling, and stabilizing fractures—do not align with the primary and urgent intent of a tourniquet's use. Instead, they focus on different aspects of injury management or physiological responses that are not the primary concern when dealing with severe bleeding.