168 DEPRESSANTS TO CENTRAL NERVOUS SYSTEM 



ized into an inhaler. Anesthesia is produced very quickly (1 — 2 

 minutes) but without total muscular relaxation, and recovery is 

 almost as rapid, on account of which it is difficult to maintain anes- 

 thesia for any length of time. Ethyl chloride is but little used m 

 veterinary medicine and almost entirely as a local anesthetic. 



Ethyl Bromide resembles the preceding drug, but is not so 

 volatile. It has been practically abandoned. 



Bromoform is not sufficiently volatile to be of use as a general 

 anesthetic. 



Untoward Sequelae from Ether. 



1. Of respiratory organs. Bronchitis, pneumonia or edema of 

 the lungs may take place. Miiller claims that there is greater 

 danger of pneumonia if the anesthetic is repeated within a few days. 

 The cause of these conditions is still in doubt, some authorities claim- 

 ing that they are due to irritation and others that they are due to the 

 patient catching cold. Stursburg, working upon dogs, found that if 

 the ether were allowed to evaporate freely there was surface chilling 

 with rise of blood pressure from reflex constriction of the internal 

 arteries. This did not occur with chloroform. It was believed that 

 the rapid evaporation of ether by the open method made the vapor 

 very cold and this in itself might be enough to irritate the respiratory 

 tract. On this account some anesthetists resort to warmed vapor. 

 This point is not yet cleared up. Seelig foimd that the inhaled gas 

 did not cool the trachea but that the rapid evaporation of the ether 

 cooled the air about the patient. 



2. On kidneys. Acute nephritis and acidosis sometimes follow 

 ether anesthesia. This is frequently seen in cats, even following short 

 periods of anesthesia. It does not appear until after several days 

 (4 — 8). The symptoms are: rise of temperature to 103°^105° T., 

 complete loss of appetite, dullness, stupor, and persistent emesis. 

 The animals succumb in from 24 — 48 hours after the first symptoms 

 appear. Autopsy shows acute parenchymatous degeneration of the 

 liver and kidneys. The urine contains considerable acetone. 



Measures to Prevent Complications from General Anesthesia. 



1. Preliminary injection of sedatives. See Morphine scopola- 

 mine p. 182. 



2. A hypodermic injection of a small dose of atropine might be 

 given to stimulate the respiratory center, lessen the salivary secre- 

 tion and prevent primary stimulation of the vagus. 



3. Start anesthesia in dogs with chloroform to lessen the period 

 of excitement. Then continU^e with ether as soon as the animal 

 reaches the anesthetic stage. 



4. To prevent acidosis, some recommend the administration of 



