CORRELATION OF CONCENTRATIONS OF ETHER IN ARTERIAL BLOOD WITH ELECTRO–ENCEPHALOGRAPHIC PATTERNS OCCURRING DURING ETHER–OXYGEN AND DURING NITROUS OXIDE, OXYGEN AND ETHER ANESTHESIA OF HUMAN SURGICAL PATIENTS

Abstract

Observations were made on 31 patients ranging in age from 26-77 yrs. undergoing abdominal procedures using N2O-O2-ether or O2-ether anesthesia. Concns. of ether and N2O were detd. on arterial blood samples drawn at intervals during anesthesia, using a mass spectrometric technic. The correlation between the concn. of ether in arterial blood and the eeg. level for 225 observations was remarkably high. The means ranged from 52 mg. of ether/100 cc. blood at eeg. level of 1, to 120 mg./100 cc. blood at ecg. level of 5 in what is almost a straight line relationship on the graph. Likewise, those cases in which the blood N2O concn. was in excess of 10 mg.%, the mean values gave an almost straight line graph; it was displaced somewhat below the line representing the ether-02 group, meaning that a lower ether concn. was required to produce each of the eeg. levels studied when N2O was present.