The Use of Extracorporeal Circulation and Profound Hypothermia in the Treatment of Ruptured Intracranial Aneurysm

Abstract

T HE aim of direct surgical t reatment in cases of ruptured intracranial aneurysm is the prevention of recurrent hemorrhage by obliteration or reinforcement of the sac. The results of t reatment are in large part predicated on the pre-operative condition of the patient, 4 particularly in relation to the state of the arterial tree (age, hypertension, local spasm) and the presence of cerebral edema, infarction or clot. The deep exposure required adds further insult to the brain damaged through retraction, injury to small perforating arteries or the parent vessels, and the production of arterial spasm. To increase the safety of operation various adjuncts have been favored, such as hypotension, urea and hypothermia. Conventional hypothermia introduced by Botterell et al. 4 has become used widely in the protection of the brain during craniotomy in these cases. Experimentally at ~8~ cerebral metabolism is reduced below 50 per cent s and the effects of hypoxia have been avoided in patients during intervals of 5 to 10 min. of occlusion of the carotid and/or vertebral artery. Ear ly favorable impressions are now under scrutiny, and Hamby 7 has stated recently that in his cases the use of hypothermia has not increased useful survival materially. From experience in this unit conventional hypothermia, with or without urea, has not prevented the development of postoperative arterial spasm and ischemic brain damage which, in our opinion, are chief causes of morbidity and mortali ty resulting from early direct surgical attack. Cardiovascular surgeons introduced profound hypothermia to protect the brain during longer periods of circulatory arrest in