CHANGES IN BRAIN VOLUME DURING ANESTHESIA: THE EFFECTS OF ANOXIA AND HYPERCAPNIA

Abstract

This investigation was instigated by an unfortunate anesthetic complication which occurred in the Neurosurgical Service of the Massachusetts General Hospital in 1938. A young woman who was rapidly losing her vision because of a hypophysial adenoma that compressed the optic chiasm had a complicating severe bronchiectasis. Operation was therefore undertaken with only local infiltration anesthesia. The moment the tumor had been satisfactorily exposed, however, the patient lost her nerve and insisted that she be placed under general anesthesia. In view of the extensive bronchiectasis it was decided that a relatively low concentration of nitrous oxide with oxygen might be given. Since an intratracheal tube had not previously been inserted and it was deemed inadvisable to disturb the patient's position sufficiently to insert one, it appeared wiser not to use ether. With the onset of a minor degree of cyanosis as the gas was administered, the exposed cerebral hemisphere began to