Prolonged suspended animation in puppies

Abstract Three groups of a total of 26 puppies were subjected to surface-induced hypothermia with or without limited left-heart bypass to seek recovery after 2.5-hr total circulatory arrest. In spite of various protective measures, surface-induced hypothermia which was carried out until the effective circulation ceased, failed to protect the animal from 2.5-hr circulatory arrest. With a combination of limited leftheart bypass, the central nervous tissue tolerated the procedure better than expected. Metabolic derangements, although severe immediately after the procedure, were reversible. Respiratory distress was a serious problem, which was considerably alleviated in the 3rd group of 10 puppies by perfusion of the lung with a solution approximating the intracellular electrolyte composition. Six puppies of this group survived the procedure, 5 without any persistent disorders. These results indicate the possibility of 2.5-hr hypothermie circulatory arrest.