The recent application in man of deep hypothermia and circulatory arrest without an extracorporeal oxygenator15 was followed by reports of brain damage in children undergoing this procedure.3 The mechanism of this complication has not been elucidated. It has been suggested that gas solubility is perhaps the major practical consideration as far as temperature effects in the blood are concerned because during rapid cooling and rewarming, the great temperature difference could result in gas embolism (Fig. 1). These facts led to the experimental use in dogs of continuous extracorporeal oxygenation and circulation during deep hypothermia with arterial blood of high oxygen tension at relatively high flow rates. This experimental model was devised so that the animals would be subjected to extreme conditions which theoretically should result in gas embolization.
Ten dogs weighing between 14.1 and 19.8 kg. were anesthetized with intravenous sodium pentobarbital (25 mg. per kilogram) and