Page 627 - My FlipBook

USE OF GENERAL ANESTHETICS. 625

The manner in which the appliance is used is as follows : The valves
in the mixing-chamber (Fig. 569) are closed, then oxygen is let into its
compartment of the receiving-bag until the latter is nearly filled, when
the nitrous oxid is admitted into its compartment. The patient being
prepared, the inhaling-tube or hood is placed in position, and the
patient is directed to breathe—long, full, and steadily. If the tube is
used it is necessary to close the nose by the thumb and finger.

Fig. 568.

Complete apparatus of It. Ik'Witt for administering mixed nitrous oxid and oxygen.
The valves are not changed for a few inhalations, during which time
only air is inhaled ; then, pressing the indicator a downward to the first
notch Ij, the air is cut off, and the patient receives pure nitrous oxid
;
this is allowed for a few more inhalations, and then the indicator is car-
ried to the next notch and one part of oxygen is allowed to pass into
the respiration. When the indicator is carried to the third notch two
parts are received by the patient, and so on until the maximum amount
of oxygen required by the patient has been reached.
It has been found by careful study of many thousands of cases and
by special scientific investigation that the asphyxial condition incident
to most cases of nitrous oxid inhalation is quite unnecessary to the pro-
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