A pneumatic antishock garment (PASG), also known as medical antishock trousers or a MAST suit, consists of inflatable bladders sandwiched between double layers of fabric. When inflated, a PASG places external pressure on the lower extremities and abdomen, creating an autotransfusion effect that squeezes blood superiorly and increases blood volume to the heart, lungs, and brain by up to 30%.

A PASG is used to treat shock when systolic blood pressure falls below 80 mm Hg or below 100 mm Hg when accompanied by signs of shock. It can control abdominal and lower extremity hemorrhage as well as help stabilize and splint pelvic and femoral fractures.

Use of a PASG is contraindicated in patients with cardiogenic shock, heart failure, pulmonary edema, tension pneumothorax, or increased intracranial pressure. The device should be used cautiously during pregnancy.