In the future, the indications for HBO therapy in acute peripheral ischemic injuries will likely be based on objective criteria rather than, as at present, on clinical diagnoses alone. This chapter offers objective criteria for using HBO in crush injuries and compartment syndromes. The pathophysiology of ATPI are well defined. Hyperbaric oxygen mediates the effects of ATPI through four mechanisms: hyperoxygenation, vasoconstriction, reperfusion, and host factors. The cost benefits of using HBO will be substantial, since complications from ATPI are very expensive. As objective criteria replace the presently used subjective criteria, hyperbaric oxygen therapy will become an integral part of trauma management of these injuries.