In which scenario is the use of a tourniquet indicated?

The use of a tourniquet is indicated in cases of severe bleeding from an extremity. When a patient experiences significant arterial bleeding that cannot be controlled by direct pressure, a tourniquet can be an effective tool to stop the blood flow. It works by applying pressure to compress blood vessels and minimize blood loss, which is critical in situations where a patient's life could be at risk due to hemorrhage.

In this context, severe bleeding from an extremity presents an urgent situation where rapid intervention is necessary to prevent shock or death. Proper application of a tourniquet can stabilize the patient's condition until further medical help can be accessed. In contrast, scenarios involving minor lacerations, signs of infection, or a sprained ankle do not warrant a tourniquet, as these situations typically do not involve life-threatening blood loss and can be managed with less invasive methods.