Effects of Hyperbaric Oxygenation on Coronary Artery Occlusion in Pigs

Abstract

To evaluate more precisely the possible protective effect of hyperbaric oxygenation in experimental myocardial infarction, gradual occlusion of a coronary artery was produced in the pig. Ameroid constrictors designed to produce complete occlusion within 48 hours were placed on the left anterior descending coronary artery of 24 young farm pigs. Of these, 12 were placed in a hyperbaric chamber at 1.25 atmospheres absolute and allowed to breathe 100% oxygen for a maximum of 32 hours. For control studies 12 other pigs were handled in a similar manner outside the chamber while breathing air at normal atmospheric pressure. Pigs treated with hyperbaric oxygenation outlived the untreated pigs. Pathological and histochemical studies of the hearts revealed that pigs treated with hyperbaric oxygenation had a high incidence of myocardial infarction, whereas only two pigs in the untreated group showed any evidence of myocardial damage. These findings suggest that moderate but prolonged hyperbaric oxygenation may lengthen life during and after coronary occlusion. This prolongation of life may permit the development of pathologically detectable myocardial infarctions.