What is a sign that a tourniquet may be required?

A sign that a tourniquet may be required is severe, life-threatening bleeding. This type of bleeding is characterized by a rapid loss of blood that can lead to shock or even death if not controlled immediately. In such cases, applying a tourniquet can help to restrict blood flow to the affected area, providing a critical stop to the hemorrhage and buying time for the individual to receive further medical intervention.

Minor bleeding or bleeding controlled by direct pressure typically does not require a tourniquet, as these situations can be managed through basic first aid techniques like applying direct pressure or a bandage. None of the other choices indicate a situation where a tourniquet would be necessary, making severe, life-threatening bleeding the only appropriate context for its use.