AEther Fortior

The stronger ether.

Chloroformum Purificatum

Purified chloroform.

Neither of these anaesthetics should be used until its conformity to the standard of the United States Pharmacopoeia has been ascertained. The tests of purity are given under their respective heads in the preceding article.

The term anaesthetic, proposed by Dr. Oliver Wendell Holmes, means an agent capable of producing anaesthesia, or insensibility to pain. It is true, anaesthesia is a term which, according to its etymological signification, should be applied to loss of sensation of touch, chiefly, and analgesia should be used to signify loss of the sense of pain; but the word anaesthesia, as expressive of the state of profound unconsciousness induced by anaesthetics, is now so firmly established by usage that it were better to retain it. Insensibility to pain (analgesia) may be produced, without simultaneous loss of common sensation, touch (anaesthesia). By the inhalation of ether, chloroform, bichloride of methylene, nitrous oxide, and some other agents, the functions of animal life can be so far suspended that surgical operations involving intense pain, and certain natural processes, accompanied by great suffering, can be performed entirely without the consciousness of the subject concerned.

Physiological Actions

When the vapor of ether or chloroform is inhaled, a sense of faucial irritation and of the need of air is experienced, and more or less cough is produced. The irritation of the fauces excites the flow of mucus, and the reflex act of swallowing. The feeling of need of air causes the patient to push aside the inhaler or sponge, and in children may lead to violent struggling. The sensibility of the glottis is soon diminished, the coughing ceases, and the inhalation then proceeds quietly.

The first effect is a general exhilaration, the pulse increases in frequency, the respirations become more rapid, and sometimes assume a sobbing or convulsive character; the face flushes; talking, laughing, crying, singing, and sometimes praying, indicate the cerebral intoxication. This stage of excitement varies in duration in different individuals, and is more pronounced in character and more persistent in those of mercurial disposition, and in the hysterical. At this period, although the patient can be easily aroused, sensibility to pain is decidedly diminished ; although the sense of touch may be preserved, taste and smell are abolished, and the sight is either abnormally acute or is perverted by illusions. If the inhalation be continued, the patient passes into the condition of complete insensibility. In women and children, and males reduced by illness, the production of insensibility. if the anaesthetic be not inhaled too rapidly, takes place quietly; but, if the subject be a robust male, in full health, especially if the inhalation has been proceeded with rapidly, the stage of insensibility is preceded by a tetanic convulsive stage, in which the voluntary muscular system and the respiratory muscles become rigid, the breathing stertorous, the face cyanosed. This condition of rigidity is similar to, if not identical with, the tetanic stage of the epileptic paroxysm. If the inhalation of the anaesthetic be pushed still further, the tetanic rigidity subsides, the cyanosis disappears, the breathing proceeds quietly, and a condition of complete muscular relaxation, and of abolition of reflex movements, is established. When this is accomplished, the arm drops without resistance when let fall, the conjunctiva is insensible to irritation, the pupils do not alter in size when exposed to light, and no mechanical irritation awakens the least consciousness of pain. The surface is cool, and bathed with abundant perspiration, the countenance is placid, the eyes closed, the pupils rather contracted than dilated; the respiration easy, but more shallow than normal; the pulse slower—it may be feebler, it may be stronger than in health. The functions of the cerebrum are suspended; only the lower centers, presiding over respiration and circulation, continue in action. Out of this condition, and without interference, the patient will presently emerge. If, however, the inhalation be continued, these organic functions will be suspended, and life will be terminated by the cessation of the action of the heart and of the respiratory organs.

There are several modes of dying from anaesthetic vapors: 1. By the first mode, the death is sudden and occurs very soon after the inhalation has begun, and is ascribed to "irritation of the peripheral nervous system, accumulation of carbonic acid in the blood, and arrest of the action of the heart." This explanation, the author submits with diffidence, seems very unsatisfactory, for phenomena of this kind, up to the point of cardiac paralysis, must ensue in all cases of chloroform narcosis. The sudden death, at the beginning of inhalation, seems to be more properly explicable on the theory that the first chloroform vapor which reaches them paralyzes the cardiac ganglia, already in an abnormal state of susceptibility from causes not now understood, for this accident sometimes occurs in persons who have previously taken the anaesthetic without unfavorable symptoms of any kind.

2.  By the second mode, called by Richardson epileptiform syncope, death ensues in the stage of rigidity preceding complete muscular relaxation, and is due to tetanic fixation of the respiratory muscles, and consequent interference with the pulmonary circulation, accumulation of blood on the venous side, and arrest of the heart's action. In these cases respiration ceases before the pulsations of the heart cease.

3.  By paralysis of the respiratory muscles. Death ensues during the stage of complete muscular relaxation, and the action of the heart continues for some seconds, or even minutes, after respiration has ceased.

4.  By paralysis of the heart. This also occurs in the course of complete insensibility; the motor ganglia are paralyzed, and the heart suddenly ceases to act, the respiration continuing for a short time longer.

5.   This mode of dying is made up of two factors: depression of the functions by chloroform narcosis, and the shock of the accident, or the surgical operation. Death may ensue during the inhalation, or may occur afterward.

Conditions of the Organism rendering the Use of Anaesthetics dangerous.—Experience has demonstrated that old drunkards are peculiarly unfavorable subjects. When tumor or abscess of the brain exists, it is dangerous to administer anaesthetics. Instances-of sudden death under these circumstances are relatively numerous. Very much enlarged tonsils, swollen epiglottis, aedema of the glottis, are contraindications, but not insuperable, to the use of anaesthetics. Emphysema of the lungs is so frequently accompanied by ischaemia-of the arterial, and engorgement of the venous side of the systemic circulation, and with dilatation of the right cavities, that it must be considered a dangerous state in which to administer chloroform, or even ether. Fatty change in the muscular substance of the heart must be considered peculiarly unfavorable, for more deaths have ensued from this cause than any other.

Chloroform and ether have been administered with safety in cases of phthisis and heart-disease (valvular lesions), the muscular substance and its contained ganglia being free from structural change.

Experience has abundantly demonstrated that those reduced by illness and disease, and the feeble, bear anaesthetics better than the healthy and robust; that children and women are better subjects than adults and men; that anaesthetics are safer when given for operations for disease than for injury.

Incomplete anaesthesia is a condition of danger. Numerous accidents have occurred from the use of anaesthetics for trivial operations —notably for extraction of teeth—in which but a partial degree of insensibility is induced. In such cases the heart, enfeebled by chloroform narcosis, is suddenly paralyzed by the reflex action proceeding from the peripheral injury. The district of tissue supplied by the fifth nerve is an especially dangerous region, owing doubtless to the intimate connection of the nucleus of the fifth with the nucleus of the pneumogastric. By far the largest number of fatal cases have resulted from a neglect of this rule: it is never safe to proceed in a surgical operation with anaesthetics, unless complete insensibility has been produced. The author is aware that Trousseau and Pidoux have attributed the number of cases of fatal chloroform narcosis, which have occurred in England, to the fact that the just-mentioned rule is adhered to by English surgeons. Their words are as follows: "En Angleterre, les chirurgiens portent l'ethérisation jusqu'd l'abolition de toutes les facultés animales, jusqu'au commencement de la période d'ethérisme organique. Plus prudents sous ce rapport que leurs confréres de la Grande-Bretagne, les chirurgiens francais ont l'habitude de s'arréter des que la sensibilité aux excitations de la peau est abolie et que la resolution musculaire commence. Cette prudence explique comment les chirurgiens francais ont éprouvé moins d'accidents graves et compté moins de morts subites." (Vol. ii, p. 322.)