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August 1957

Objectivity of the Sedation Threshold

Author Affiliations

D.P.M., Sutton, Surrey, England

From Banstead Hospital.

AMA Arch NeurPsych. 1957;78(2):194-196. doi:10.1001/archneurpsyc.1957.02330380084011

Introduction and Problem  During the last few years a number of papers have appeared in the medical journals which have been concerned with the "sedation threshold."1-4 Briefly, amobarbital (Amytal) sodium is injected intravenously at a specified rate until certain EEG changes occur in association with the onset of slurred speech. The concept of the sedation threshold owes its inception to Shagass, who defines it as "the amount of sodium amytal, in mg/kg, required to produce an inflexion point in the 15 to 30 c/sec amplitude curve, which occurs within 80 sec (1 mg/kg) of the time when slur is noted."4 Shagass goes on to say that "the slur localises the threshold roughly, the EEG inflexion point does it more precisely."During the course of a preliminary investigation into the general usefulness of a patient's sedation threshold as measured by the onset of slurred speech, we were impressed by

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