What should the first step be when encountering a casualty with major bleeding?

The first step when encountering a casualty with major bleeding is to apply direct pressure to the wound. This immediate action is vital because direct pressure helps to control hemorrhage by promoting clot formation at the site of the injury. Controlling bleeding is the highest priority in emergency care and is essential to prevent excessive blood loss, which can lead to shock and potentially be life-threatening.

Applying direct pressure is a straightforward and effective first response that can stabilize the casualty's condition while further assessment and treatment are considered. It can often be achieved quickly, which is crucial in a combat or emergency situation where every second counts. Once the bleeding is under control, other assessments can be made, but managing the bleeding must come first to preserve life.