Spencer’s anti-shock trousers have three functions and are made for traumatized patients. First, it maintains homeostasis by putting pressure to the tissue near blood vessels that are bleeding in order to reduce blood flow. Second, when trousers are applied to patients who are suffering from shock, the internal air chambers swell and immobilize the equivalent of 2 units of blood from the patient's extremity and abdomen towards the heart by compressing draining vessels in the pelvis and legs. Third, fractures of the pelvis and lower limbs as well as comminuted fractures are immobilized by the trousers. It has many applications including hypovolemic shock and abdominal hemorrhage due to extensive trauma or penetrating wounds that other interventions like plasma expanders cannot control.