Hemodynamlc Effects of Hyperbaric Oxygenation in Experimental Acute

• Hyperbaric oxygenation has been re-ported to be beneficial in a variety of condi-tions characterized by ischemia. The rationale for its use in acute myocardial infarction, as in other ischemic conditions, depends on the fact that the amount of physically dis-solved oxygen in the capillaries, and hence potentially available for the tissues, is directly related to its partial pressure in the capillaries. With the inhalation of 100 $ oxygen at three atmospheres (absolute) pressure, the arterial p(\ » rises, theoretically, to about 2200 mm Hg as compared to a level of about 100 mm Hg when room air is breathed. The amount of oxygen physically dissolved in the blood plasma rises from 0.3 vol % when breathing room air to about 6 vol % when breathing 10035 oxygen at three atmospheres pressure. Previous studies of the use of hyperbaric oxygenation in experimental myocardial in-farction have shown: protection against ven-tricular fibrillation in dogs breathing oxygen at two atmospheres following coronary artery ligation;1 diminution in the size of the myo-cardial infarction produced by coronary ar-tery ligation in dogs breathing oxygen at three atmospheres compared to those breath-ing room air;2 and less rise in serum glutamic oxalacetic transaminase and serum glutamic pyruvic transaminase levels following coro-nary artery ligation in dogs breathing oxyge