ANALGESIA VS. ANESTHESIA
The reader should understand the difference between analgesia and anesthesia. Anesthesia refers to the condition in which the patient is more or less unconscious—wholly or partially oblivious to what is going on, and, of course, entirely insensible to all pain. Analgesia is a term applied to the loss of pain sensation. The patient may not be wholly or even partially unconscious—merely under the influence of some agent which dulls, deadens, or otherwise destroys the realization of pain. This is the condition aimed at by the proper administration of any form of "twilight sleep," whether by the scopolamin-morphin method, or by the nitrous oxid ("sunrise slumber") method.
Any method of treatment which can more or less destroy the pain of labor without in any way interfering with its progress, and which in no way complicates its course or leaves behind any bad effects on either mother or child, must certainly be hailed with joy by both the patient and the physician. While chloroform has served these purposes fairly well, there have been numerous drawbacks and certain dangers; and it was the knowledge of these limitations in the use of both chloroform and ether, that has led to further experimentation and the development of these newer methods of producing satisfactory analgesia—freedom from pain—without bringing about such a state of profound anesthesia as accompanies the administration of the older methods.
It should be borne in mind that in using "sunrise slumber" (nitrous oxid) for labor pains, the gas is so administered that the patient is just kept on the "borderline"—in a typical "twilight" state—and not in the condition of deep anesthesia which is developed when nitrous oxid is employed by physicians and dentists as an anesthetic for major and minor surgical operations.
Analgesia is the first stage of anesthesia—the "twilight zone" of approaching unconsciousness—in which the sense of pain is greatly dulled or entirely lost, while even that which is experienced is not remembered. It seems to the authors that "gas" is the ideal drug for producing this condition whenever it is necessary, as nitrous oxid is the most volatile of anaesthetics, acts most quickly, and its effects pass away most rapidly, while its administration is under the most perfect control—it may be administered with any desired proportion of oxygen—and may be discontinued on a moment's notice. It is practically free from danger even when continued as an analgesic for several hours. Nitrous oxid never causes any serious disturbance in the unborn child, as chloroform sometimes does when used too liberally.