Military anti-shock trousers (or Pneumatic Anti-Shock Garments) are medical devices used to treat severe blood loss. They are also indicated for the stabilization of unstable pelvic fractures in the field prior to transport. MAST are typically carried and used by emergency medical technicians and paramedics, although they are sometimes carried by fire department first responder trucks, and, in some states, first responders can apply and inflate them under direct medical control.