Ether is more pungent and less agreeable to breathe than chloroform, but the chief advantage usually connected with its use is its supposed factor of safety.
On the other hand, the accidents which are due to ether are in a large measure those common to the use of any anesthetic agent. Among the most prominent is arrest of respiration, which may be caused either by mucus or some foreign body in the air passages, or by the tongue dropping back in the pharynx, and the impediment to respiration thereby offered. When the cause of the difficulty is ascertained it is usually easily removed. Should great pallor accompany these symptoms, then, it is usually because the heart as well is at fault, and vigorous stimulation of this organ should be promptly instituted.
Another disadvantage pertaining to ether results from the irritation which its vapor produces in the bronchi and lungs, or in the kidneys during its elimination. From the former may result bronchitis, congestion, or even pneumonia; the latter more often of the catarrhal type than of the croupous. As the result of renal irritation there may be temporary albuminuria, or the congestion resulting may assume so serious a type as to produce absolute suppression (anuria), which is practically always fatal. Ether is said to be particularly undesirable in cases of diabetes, because of the resulting acetonuria. Patients have even been known to pass from anesthesia into diabetic coma.
It has been found that complications are more common in males than in females, but more severe in the latter. Vomiting following the use of ether is a frequent and most unpleasant sequel. It is to be prevented by previous lavage, as well as by the same measure at the conclusion of the operation. It will rarely subside when present until the ether vapor has been eliminated. So far as it is possible to suppress it with drugs probably 2 Gm. doses of chloral and one of the bromides, with a little laudanum, given by the rectum in salt solution or a little starch-water, will give the best results.
As already stated, it was formerly held that anesthesia was carbon dioxide poisoning, plus something else which was vaguely described by different authorities; much clearer notions now prevail regarding the mechanism of anesthesia. A few years ago Meyer and Overton concluded that anesthesia is produced by solution of the fatty constituents of the cells by the anesthetic absorbed, this being true at least with chloroform and ether, both of which are solvents of fat. The absorbability of the anesthetic varies with the blood temperature, this varying widely between the cold-blooded and warm-blooded animals. They estimate that 1 part of ether to 400 parts of serum is necessary for complete anesthesia in man, while one part in 4500 to 6000 parts is a sufficient proportion of chloroform. According to these views the dissolved fat is not removed from the cells, and no satisfactory explanation yet accompanies this theory, even assuming its accuracy.
Of no small importance are the experiences of Snel, who found that anesthetics decrease the bactericidal properties both of the blood and of the tissues, but that this power is quickly recovered after the elimination of the anesthetic. He furnishes reason for the theory that the thus lowered resistance of the lungs is an important factor in the production of the pneumonia which occasionally follows operations.
There is a belief that ether is more irritating to the kidneys than chloroform. This, however, does not seem to be justified by evidence, neither is the prejudice against the use of ether during the existence of albuminuria or in the presence of casts. In the presence of a high degree of albuminuria any anesthetic is dangerous, and here ether would be the less desirable of the two. Nevertheless in ordinary mild albuminuria one need not fear to give ether.
About twenty years ago it was suggested that ether anesthesia could be induced by passing its vapor into the colon through an ordinary rectal tube. There are many obvious reasons why it would be of great advantage if anesthesia could be safely practised in this way, not only in operations about the face and head, but because of the avoidance of pulmonary and gastric irritation.
The method was to thoroughly empty the colon and then connect a rectal tube with a receptacle containing ether, which was placed in warm water and the vapor passed into the intestine. It was found that patients could be readily anesthetized in this manner, but unfortunately it was also found that a considerable degree of intestinal irritation was produced.
The writer recalls one case in which this method was practised, which terminated fatally within twenty-four hours after the operation, where the autopsy disclosed a violent degree of acute colitis.[7]