Effect of Increased Oxygen Pressure on the Seizures of Epilepsy

In most patients having very frequent attacks of petit mal, seizures can be regularly induced by having the patients breathe air which is deficient in oxygen. This fact has been demonstrated by one of us (W.G.L.),1who has encountered thirteen patients in whom petit mal could be consistently induced by anoxemia. An attack of petit mal would occur when the oxygen content of the respired air had fallen to from 8 to 12 per cent, whereas consciousness in normal persons is not lost until the oxygen content is reduced to about 7 per cent. Because a low oxygen tension precipitates seizures in these patients, it seems to be a fair inference that a high oxygen tension would prevent seizures. However, oxygen under high pressure is a convulsant. This observation, made by Bert2in 1878, has been abundantly confirmed by later workers. The most detailed and recent experiments are