The importance of inhalational therapy in modern medical practice is shown by its use in cardiac failure, coronary artery disease, asthma, atelectasis of the lungs of the newborn, postoperative atelectasis, pneumonia, pulmonary edema, emphysema and cerebral thrombosis. A proper understanding of the technic is especially necessary at this time because of its value in the treatment of war gas poisoning, severe hemorrhage, acute altitude sickness, and shock.
The therapeutic use of oxygen is based on the existence of a state of anoxia or of tissue oxygen want. This may be produced by failure of an adequate pressure of oxygen to reach the pulmonary capillaries or by a lowered blood flow which is responsible for a disproportionately large amount of oxygen being taken out of the capillaries, resulting in a diminished oxygen pressure insufficient for normal function of the tissues. Oxygen want may, however, take place with a normal arterial saturation,