MIXTURE OF CHLOROFORM AND ETHER.
The mere addition of ether does not remove all the undesirable features
of chloroform anæsthesia. A heart poisoned by excess of CHCl_{3} does
not respond to ether stimulation. Nevertheless, CE mixtures of varying
proportions have great value. The less lethal drug takes on part of the
work of the more dangerous one; it also keeps the respiratory centre
active. Viewing mixtures as dilute chloroform, it is also obvious that
there will be with them a greater margin of error in dosage, than with
the pure drug.
Some chemical change takes place when the two drugs are mixed, for heat
is evolved; of the nature of this change we are ignorant.
The first mixture introduced was known as ACE, and consisted of one
part absolute alcohol, two parts chloroform, and three parts ether.
Alcohol evaporates very slowly and if it be introduced at all it should
be in much smaller proportion. Schäfer’s mixture is one part alcohol to
nine parts chloroform. Neither of these mixtures is now much used. The
most useful combination is two parts chloroform and three parts ether,
and is known as C_{2}E_{3}. In special cases, one part of chloroform to
two parts ether may be better.
Methods.
_Cones_ of varying type were at first extensively used for
mixtures. The best known is Rendle’s (Fig. 46). It is made of
celluloid, and is perforated at the top by a series of small holes
through which the anæsthetic is introduced. A sponge is packed into
the upper part of the cone, and a flannelette cover completes the
appliance. The objection to the use of this and kindred cones is that
since chloroform evaporates more slowly than ether, the more dangerous
drug is apt to collect in the sponge, completely altering the strength
of the vapour after a time. This fault is remedied to a large extent by
the open drop method now used.
[Illustration: FIG. 46.--Rendle’s Cone.]
The Open (Drop) Method.
For this the mask and ether dropper of Bellamy Gardner are admirably
suited (Fig. 27). A material less close than the gauze advocated for
open-ether is required. One layer of flannelette does very well, or
the cheap cotton towels which used to be known in Edinburgh as “penny
towels” in the pre-war period. The mask should fit the face with
reasonable accuracy: there is no reason why a gauze ring should not be
used to ensure this if the administrator is careful to adhere strictly
to a “drop” method.
The bottle into which the dropper is inserted should be of different
_colour_ to those in which pure ether is habitually carried. This is a
greater safeguard against a dangerous forgetfulness than a mere label.
As already said, the anæsthetic must be given by a strict “drop”
method. “Douching” at frequent intervals gives results far inferior.
THE TYPE OF ANÆSTHESIA is a compromise between that of chloroform
and open-ether. Respirations and colour are better than with pure
chloroform, not so good as with open-ether. The size of the pupil is
also intermediate.
SCOPE.--As elsewhere explained there are many patients to whom
open-ether cannot well be given; the greatest number of these can take
a mixture perfectly and C.E. should certainly be chosen in preference
to pure chloroform when possible. For refractory cases, it serves
admirably as the inducing agent before the use of open-ether.