During Hyperbaric Oxygen Therapy, oxygen content of the blood increases substantiallyi. Breathing 100% oxygen at the pressure of 2 ATA leads to alveolar oxygen partial pressure (in the lungs) of approximately 1,400 mmHg!!! In a unique experiment at 1960, Boerema demonstrated that experimental animals were still alive even after complete exsanguination, when breathing 100% oxygen at 3 ATAii. Using hyperbaric oxygen, sufficient amount of oxygen reaches body tissues that have been rendered hypoxic due to inherent perfusion particularities, local conditions (inflammation, hematoma, infection, microcirculatory damage etc) and/or systematic pathology (Diabetes Mellitus, medications, radiation therapy etc)
i Kindwall E. The physics of diving and hyperbaric pressures. In Kindwall EP, Whelan HT, editors. Hyperbaric Medicine Practice. 2nd ed revised. Flagstaff: Best Publishing Company;2004. p21-35.
ii Boerema I, Meyne NG, Brummelkamp WK, Bouma S, Mensch MH, Kamermans F, Hanf MS, van Aalderen W. Life without blood. J Cardiovasc Surg 1960;1:133-146.