Blood in the Brain

If doctors knew more about what goes on inside a man's head, they might be able to do more about diseases. But they have never had a window-in-the-head to match the window-in-the-stomach that one Alexis St. Martin once gave them.* Last week, after four years' experimenting, University of Pennsylvania Physiologist Seymour S. Kety, 32, thought he had the next best thing: a way of testing the brain's blood as it comes & goes.

Dr. Kety experimented on 400 patients in three different hospitals. First he inserted a needle in the internal jugular vein (which drains the brain), another in an artery, usually the femoral artery in the thigh. Then he had them breathe a 15% concentration of nitrous oxide, a gas that is easily traced.

He drew out a total of 60 cubic centimeters of blood in the two needles, about a tenth of what the average blood donor loses. By calculating the amount of .nitrous oxide that is absorbed by the brain, he determined the rate of blood flow. Thus he was able to measure the way the brain uses up its chief sources of energy: oxygen and glucose. Already he has demonstrated that unconscious patients use only half the normal amount of oxygen and glucose, that schizophrenics use as much oxygen for their irrational thinking as a sane person does for normal thinking.

* After St. Martin got a hole in his stomach from a shotgun blast in 1822, he lived 58 years, to the great profit of medical researchers. A doctor put food directly into his stomach through a flap, and got a close-up picture of digestion.

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