Minimum Anesthetic Concentration Research Articles

非バルビツレート静脈麻酔剤の研究 (第3報)

Relationship between physicochemical properties and anesthetic activity was examined with 34 kinds of compounds related to N, N-diethyl-2-(2-methoxy-4-allylphenoxy)-acetamide. Minimal anesthetic concentration and saturation concentration of these compounds at 25° against tropical fish, guppy (Lebistes reticulates), were determined, as well as Ferguson's thermodynamic activity. Distribution ratio of these compounds between water and oleyl alcohol was measured by the method of Meyer and Hemmi, and concentration of the compounds in oleyl alcohol at anesthetic concentration was calculated. Thermodynamic activity was calculated from the surface activity of the saturated solution and effective anesthetic solution, according to the method of Feursteine. It was thereby assumed that N, N-diethyl-2-(2-methoxy-4-allylphenoxy)-acetamide and N, N-diethyl-2-(2-methoxy-4-propylphenoxy) acetamide had the same action mechanism as ether and chloroform.

Experimental Observations on the Anesthetic Properties of Divinyl Ether.

Studies have been reported on the anesthetic properties of certain unsaturated ethers, from which it seems that divinyl ether is a compound deserving thorough investigation as a potentially useful general anesthetic agent. This earlier survey was made on an apparently impure sample (B.P. 36-39°C). Thanks to Ruigh and Major an adequate supply of pure divinyl ether (B.P. 28.2-28.5°C, corrected; Sp. Gr. 0.77 at 20°C.) is now available, and it is a pleasure to acknowledge their kindness in furnishing the substance for our present use. The range of minimal anesthetic concentration of divinyl ether was found to be between 1.35 and 1.75 millimols per liter of air. This was estimated by inhalation for 10 minutes in a series of 104 mice by a method essentially the same as that described by Johnston. The time period required to anesthetize 60 different mice at the minimal certain anesthetic concentration (1.75 millimols per liter of air) varied between 30 and 70 seconds. This is more rapid on the average than the time range required to anesthetize this same group of mice with the minimal certain anesthetic concentration of chloroform (0.3 millimols per liter of air). During anesthetization with divinyl ether, mice show a short excitement period, rapidly become ataxic, and may exhibit running movements during the initial period of anesthesia. Upon removal from the anesthetizing chamber, the mice recover at the concentration noted, within 40 seconds. The range of minimal lethal concentration of divinyl ether for mice is apparently above 6 millimols per liter of air on 10 minutes inhalation. In semi-quantitative experiments in dogs, divinyl ether in oxygen anesthetizes much more rapidly than di-ethyl ether in oxygen, and without as much excitement or struggling during induction.