MAST: medical antishock trousers.

MAST are a simple, safe and sound device with applicability in all shock states; they provide a number of benefits to the hypotensive patient. The main benefits seem to be autotransfusion of peripherally pooled blood originating from the MAST encased areas, increase in peripheral vascular resistance, external tamponade of bleeding vessels and an aid to stabilization of fractured bones of the pelvis and lower extremities. Because an area of hypoperfusion can lead to complications, the pathophysiologic effects of MAST must be understood. The greatest complications occur when MAST are too rapidly removed. They must be removed in an appropriate place by trained physicians under controlled conditions. The key is to deflate the MAST over a prolonged period of time using a gradual release of external pressure. Volume status and acid-base balance must be carefully monitored. In the last few years MAST have had an ever expanding role in both the pre-hospital and hospital phases of care of the critically ill and injured patients. All physicians involved in the care of these patients must be familiar with this device. Applied and removed properly, MAST will sustain blood pressure and save lives.