ven
catheter introduced into the trachea, ether-laden air from an
insufflation apparatus is piped down to the lungs continuously, and
the strong return-flow prevents blood and secretions from entering the
lower air-passages. The catheter should be of a size, relative to that
of the glottic chink, to permit a free return-flow. A number 24 French
is readily accommodated by the adult larynx and lies well out of the
way along the posterior wall of the larynx. Because of the little room
occupied by the insufflation catheter this method affords ideal
anesthesia for external laryngeal operations. Operations on the nose,
accessory sinuses and the pharynx, apt to be attended by considerable
bleeding, are rendered free from the danger of aspiration pneumonia by
endotracheal anesthesia. It is the safest anesthesia for goiter
operations. Endo-tracheal anesthesia has rendered needless the
intricate negative pressure chamber formerly required for thoracic
surgery, for by proper regulation of the pressure under which the
ether ladened air is delivered, a lung may be held in any desired
degree of expansion when the pleural cavity is opened. It is indicated
in operations of the head, neck, or thorax, in which there is danger
of respiratory arrest by centric inhibition or peripheral pressure; in
operations in which there is a possibility of excessive bleeding and
aspiration of blood or secretions; and in operations where it is
desired to keep the anesthetist away from the operating field. Various
forms of apparatus for the delivery of the ether-laden vapor are
supplied by instrument makers with explicit directions as to their
mechanical management.

We are concerned here mainly with the technic of the insertion of the
intratracheal tube. The larynx should be examined with the mirror,
preferably before the day of operation, for evidence of disease, and
incidentally to determine the size of the catheter to be introduced,
though the latter can be determined after the larynx is
laryngoscopically exposed. The following list of rules for the
introduction of the catheter will be of service (see Fig. 59).

RULES FOR INSERTION OF THE CATHETER FOR INSUFFLATION
ANESTHESIA

1. The patient should be fully under the anesthetic by the open
method so as to get full relaxation of the muscles of the neck.
2. The patient's head must be in full extension with the vertex
firmly pushed down toward the feet of the patient, so as to throw the
neck upwa