Part 28

Made from chloroform, expressed oil of almond, tragacanth and water. Should contain four per cent of chloroform. A good agent and vehicle for diarrhoea and vermifuge mixtures for small animals.

DOSE.--Dogs, 2 dr. to 1 oz.; cats, ¹⁄₂ to 1 dr.

ACTIONS.--Chloroform is a topical irritant, antiseptic, parasiticide, carminative, antispasmodic and analgesic. Full doses quickly and powerfully paralyze the cerebro-spinal nervous system; chloroform kills by paralyzing the heart and respiration; the latter effects are most rapidly produced when the drug is inhaled. Chloroform is the general anaesthetic most used for veterinary purposes except for dogs.

Externally it is rubefacient if confined or even suppurant. It also acts as a refrigerant, anodyne and local anaesthetic if not confined. It penetrates the skin very readily and on this account is commonly used in liniments to aid in the absorption of other medicines.

Chloroform compared to ether is much more irritating to the mucous membrane, and causes violent gastro-enteritis, if swallowed undiluted; it is less stimulating and more depressing to the heart and circulation. For inhalation it requires much more air; is less irritant to the air passages than ether; is uninflammable, more pleasant, more prompt in action, has a shorter stage of excitement, causes a more profound narcosis, and is not so nauseating as ether and is cheaper. Statistics show it to be five times more fatal than ether.

The results of various experiments show that chloroform and ether both act in the same manner upon the heart and respiration, paralyzing the latter first; but chloroform acts much more quickly and powerfully than ether in both directions. But when chloroform is inhaled in a concentrated form it generally paralyzes the heart first.

USES.--Chloroform should be used as an aid in painful and prolonged cases of parturition, especially where you have tumultuous contraction of the uterus, or rigid contraction of the os. Use just enough by inhalation to dull the pain and relax the parts; it will aid you in your efforts to rectify abnormal presentations by relaxing the parts.

Internally it is used in spasmodic and flatulent colic as it is an antispasmodic carminative and anodyne in its effects; chloroform combined with belladonna and opium is very beneficial in spasmodic coughs, given in linseed gruel or water, well diluted; in liniments about one or two ounces to the pint. Chloroform is used in chronic diarrhoea with other medicines, such as morphine, capsicum, camphor, oil of peppermint and ether. It is also a good taeniacide.

ANESTHESIA

Anesthesia is divided into three stages; the stimulant, anaesthetic and paralytic.

In the first stage there is struggling and excitement, due partly to the action of the drug and partly to fright. The local irritant action of the vapor causes choking and coughing, which also induces struggling.

The respiratory and cardiac centers are temporarily stimulated, as a consequence of which the pulse and respiratory movements are increased in force and frequency and blood tension is raised.

The smaller animals, particularly the dog, may vomit during the first stage of anaesthesia. In the first stage the dog may bark, whine or howl, the horse neighs and groans; other animals give expression to sounds more or less characteristic to their species.

The second or anesthetic stage is characterized by loss of consciousness, sensation, motion and partial loss of reflex action and is that state suitable for operations. The stimulating action of the anesthetic has passed and there is now depression of the cerebral functions, the motor centers. The voluntary muscles are completely relaxed, the sphincters occasionally, the patient lies absolutely motionless, the cornea fails to respond to irritation, i. e., winking is not produced when the cornea is lightly touched with the finger. Sometimes the muscles are rigid and twitching during this stage of anesthesia, though sensation and consciousness are absent. In the anesthesia stage the pulse is slow, full and strong, due to lowered blood pressure, the breathing is slow and shallow but regular.

The third or paralytic stage, which must be carefully watched against, poisoning is beginning and there is depression of the three great medullary centers controlling the heart, respiration and vascular tension and also the posterior reflex centers of the spinal cord, so that the urine and faeces are passed involuntarily. The passage of urine frequently occurs in the first stages of anesthesia and should not of itself be considered a danger mark. When the pulse becomes rapid, feeble and irregular, the breathing is at first stertorous and then the respiratory movements become shallow and weak, with long intervals intervening between them; this irregularity is a most important danger sign. The skin and mucous membrane often become cold and clammy. The pupils are usually widely dilated, though death may occur with either dilated or contracted pupils and consequently no dependence should be put in this sign unless there has been a sudden change from one condition of the pupils to the other. The three above mentioned stages are conventional, and are not in any case so clearly defined in practice as they are described theoretically upon paper. The first stage may be either absent or prolonged, and the last stage should not be reached at all.

COMPARISON OF ETHER WITH CHLOROFORM

Ether. Chloroform. +-------------------------------+----------------------------- | More diffusible. | Less diffusible; vapor | | heavier. +-------------------------------+----------------------------- | Inflammable and explosive. | Not inflammable, but vapor | | decomposes when exposed to a | | light and causes irritation | | and some times death. +-------------------------------+----------------------------- | Stimulant to heart, except | Depresses powerfully the | in enormous quantities. | heart respiratory and | | vaso-motor centers in large | | doses. +-------------------------------+----------------------------- | Irritating (due to exclusion | Less irritating (on account | of air), may induce | of more air being required | bronchitis and nephritis. | for dilution.) +-------------------------------+----------------------------- | Respiratory centers not | Three to five times more | so easily or suddenly | dangerous (deaths) than | depressed as by chloroform. | ether. +-------------------------------+----------------------------- | Larger quantities required. | Smaller quantities required. +-------------------------------+----------------------------- | Less rapid. | Acts quickly. +-------------------------------+----------------------------- | More expensive. | Cheaper. +-------------------------------+----------------------------- | Kills by respiratory failure. | Death from respiratory | | failure, combined with | | cardiac depression. +-------------------------------+-----------------------------

Consequently you can see considering both drugs to be properly administered, all the advantages are in favor of chloroform except safety.

Ether is to be preferred for dogs, cats and other small animals.

Chloroform is especially dangerous for dogs, though horses stand it exceptionally well and it is preferable to ether in large animals. The safety with which chloroform may be administered to large animals frequently makes veterinarians careless; that is, they “force” the drug; they do not allow sufficient air for dilution, and though the patients may not die from the immediate effects of the drug their existence may be terminated in a few days from pneumonia or broncho-pneumonia (mechanical), due to the irritating effects of the drug.

ANAESTHESIA.--It is best to cast the large animals; after complete anaesthesia remove the hobbles.

For dogs make a cone of a towel and paper, put a sponge in the bottom, allowing a small opening in the end to admit air; pour in ether a little at a time.

In brain diseases or tumors of the brain, chloroform is dangerous. Horses with heaves or emphysema should not take chloroform; it is also dangerous in fatty degeneration of the heart. Operations during incomplete anaesthesia, especially with chloroform, are dangerous; always produce complete anaesthesia, have the stomach empty, but don’t fast animals for more than two or three meals.

Things to remember when administering an anaesthetic:

The operator must be skilled and give his attention exclusively to the production of anaesthesia, watching the respiration and pulse for signs of failure.

Do not commence operation until anaesthesia is profound, until reflex action is abolished, which can be told by touching the eye with the finger; obey this, no matter how slight the operation. The utmost care should be exercised if the patient is very old or has fatty degeneration of the heart, or lung diseases.

Great care should be exercised in operations about the mouth or trachea. See that no blood passes down the trachea. The stomach and bowels should be empty. This will cause less nausea and feed may be regurgitated and run down the trachea.

When purchasing chloroform or ether for anaesthetic purposes insist on the best; it must be pure.