ANAESTHETICS.
NEUROTICS ACTING ON THE BRAIN AND PRODUCING INSENSIBILITY.
CHLOROFORM--CHLORAL--BICHLORIDE OF METHYLENE--ETHER--AMYLENE--NITROUS
OXIDE.
The anaesthetics which have hitherto been employed in the practice of
medicine are chloroform, sulphuric ether (or a mixture of these),
bichloride of methylene and nitrous oxide, and amylene. Any of these
agents may cause death when introduced into the system by inhalation.
CHLOROFORM is a colorless, heavy, volatile liquid; having a fruity
ethereal odor and a sweet pungent taste. It is formed by the union of
chlorine and marsh gas, but more commonly by the action of bleaching
powder on ethylic or methylic alcohol. It is readily soluble in alcohol,
but very sparingly so in water. Chloroform is a good solvent of
caoutchouc, gutta-percha, camphor, wax, resin, some of the alkaloids,
&c.
The _symptoms_ produced by the vapor of chloroform may be divided into
three groups of varying intensity; briefly they are these: First, a
degree of relief from pain, the senses being but slightly affected;
second, a stage of excitement and incoherence, wherein the patient is
prone to struggle; and thirdly, a stage of which the most marked
features are complete insensibility and narcotism, with relaxation of
the muscular system. At first the patient is conscious of all that is
passing around him, but there is dizziness and singing in the ears. Then
the mental functions are impaired, there is often excitement, the saliva
is increased, the patient pushes away the inhaler, rigidity and spasms
of the muscles may occur, and there is incoherent talk. In the next
stage there is insensibility to pain, and the conjunctiva may be touched
without causing flinching. If the use of this anaesthetic be pushed
further the breathing becomes stertorous, the muscles quite relaxed, and
the pupils dilated; while a still further increase of the chloroform
embarrasses and then stops the breathing and arrests the heart's action.
Many cases of death from the vapor of chloroform have occurred, the
fatal effect sometimes happening very rapidly from shock, syncope, or
convulsions. The vapor of only thirty drops has destroyed life in one
minute. Death under the influence of chloroform must not be confounded
with death from its effects. The smallest fatal dose when the drug has
been swallowed is one drachm in a boy aged four.
The effects of chloroform taken by the mouth are of the same description
as those which follow the inhalation of this agent; with this
exception, that the fatal result seems to be longer deferred. A case
reported in the _Medical Times and Gazette_, 10th May, 1862, illustrates
the symptoms, &c., in a clear way. Mr. M., thirty-four years of age, a
highly-gifted restless man, was in the habit of inhaling chloroform on
account of sleeplessness. He was very sensitive to its action. At about
12.30 A.M. on the 7th October, 1861, he drank some chloroform; the
quantity being uncertain, though it may be inferred that it was about
one ounce. At 7.15 he was in such a profound sleep that his wife felt
uneasy, and she sent for Dr. Axel Lamm. This gentleman found his patient
in a tranquil sleep, the respiration being somewhat hurried and audible,
the pulse full but slow, the body warm, and the pupils dilated and
insensible. There was a perceptible smell of chloroform in the breath
and in the air of the room. The window was opened, ice was applied to
the head, cold affusions were used along the spine, and an enema was
administered. At 9.30 A.M., the patient was paler, breathing less
audibly, and with a weaker pulse. Artificial respiration was employed by
means of electricity, an ammonia lavement was given, and aspersions of
iced water to the chest and pit of the stomach were used alternately
with warm coverings. The stupor continued, the respired air smelt
distinctly of chloroform, the abdomen was tympanitic, and the pupils
began to contract. About 9 P.M. the eyes began to move, the pupils
seemed sensible to light, the pulse was 160, there was abundant
perspiration, and the patient sat up for a few moments and looked
surprised. Exhaustion, however, set in, and death occurred just before
midnight, nearly twenty-four hours after swallowing the poison.
A second interesting case (_Medical Times and Gazette_, 31st May, 1862)
also deserves attention. A gentleman, fifty years of age, swallowed two
ounces of pure chloroform at 8 A.M. He was not seen until 3 P.M., when
he was found in a state of deep coma. His breath smelt strongly of
chloroform, the pupils were widely dilated and insensible, the pulse
slow and feeble, the surface colder than natural, the movements of the
thorax scarcely perceptible, and sensation generally abolished. Ammonia,
sinapisms, bottles of hot water, and cold affusion did no good; but on
using a stomach-pump a quantity of chloroform mixed with watery mucus
was withdrawn, and in less than an hour the patient was able to answer
questions. For three or four days he complained of a burning sensation
in the throat and epigastrium, and then got well. A consideration of the
treatment employed in this instance cannot but suggest the idea that the
first patient might have had a better chance of recovery had the
stomach-pump been used when Dr. Lamm was first called in; though it is
difficult to conceive how any quantity of chloroform could remain in the
stomach for seven hours, without all of it being absorbed.
Various plans have been suggested for the administration of chloroform
with safety, but this must be remembered: the use of anaesthetics is at
all times attended with risk, and we can only at best diminish the
danger. Apparatus may be used so as to reduce the risk to a minimum; but
this is plain, any contrivance which in itself requires much attention,
and thereby diverts it from the patient, is bad. More lives have been
lost by bungling in its administration than from the noxious character
of the drug.
In the _treatment_ of poisoning by the vapor of any of the anaesthetics
mentioned in this chapter, we must expose the patient to a current of
pure air, use cold affusion, and employ artificial respiration until
the poison is eliminated. Galvanism may be employed to keep up the
action of the diaphragm, either directly or through the phrenics. As
these agents are got rid of through the lungs, the purity of the expired
air is one test of the elimination being complete; though of course
inferior to the evidence afforded by the subsidence of the symptoms. In
poisoning by liquid chloroform or ether the stomach-pump ought to be
promptly used.
CHLORAL HYDRATE, which with an alkali is converted into chloroform, has
of late been much used as a narcotic and for easing pain. No details of
any case of poisoning by its agency have yet been published.
BICHLORIDE OF METHYLENE has been used for anaesthetic purposes. It is
supposed to be safer than chloroform. Practically they act much alike,
and death happens with the one as with the other.
_Test._--Chloroform at a red heat is decomposed, and chlorine and
hydrochloric acid are formed. Hence, to detect it the substance supposed
to contain it may be heated so as to expel the chloroform, which should
be conducted away from it by a tube at right angles; to this heat should
be applied sufficient to decompose the vapor, and its products searched
for by the ordinary tests. The smell is a valuable criterion.
SULPHURIC ETHER.--Sulphuric ether, or ether, is a clear colorless
liquid, very inflammable, soluble in alcohol, and less so in water. It
is usually obtained by distilling common alcohol with sulphuric acid.
The effects produced by the inhalation of ether are similar to those
which result from chloroform. It is, however, without doubt a much safer
agent, but its effects are longer in manifesting themselves; it is more
irritating to the air-passages, and much more of it is required. Deaths
have occurred under its influence as under that of chloroform.
AMYLENE.--This is a colorless, volatile liquid, made by distilling
amylic alcohol (obtained from crude fusel oil, or oil of potato spirit)
with chloride of zinc.
Dr. Snow found that amylene, like chloroform, is capable of causing
sudden death by inducing over-narcotism of the heart, and paralysis of
this organ. He had two deaths from it, and it has since been entirely
given up as an anaesthetic.
NITROUS OXIDE.--Comparatively recently the laughing gas of Sir Humphrey
Davy has been introduced as an anaesthetic agent. Its successful use
depends on the total exclusion of air from the lungs during its
exhibition. It can only be used for a short time, hence it is chiefly
employed in dental operations, although it has been given for a
considerable length of time consecutively by allowing the patient to
return to the verge of sensibility before giving a fresh dose.