212 APPLIED PHYSIOLOGY 



362. Oxygen inhalations. Since the red blood cells 

 are loaded with oxygen to their full capacity as they leave 

 the lungs, they could absorb no more even if it were in- 

 haled in a pure form. When there is a shortness of breath 

 during disease, pure oxygen is sometimes inhaled to take 

 the place of the diluted oxygen of the air. When the lack 

 of oxygen is due to a diminished number of red blood 

 cells, or if the blood flows too slowly to carry enough oxy- 

 gen, inhaling oxygen can do no good, for the blood cells 

 leaving the lungs are already loaded with it. The poisons 

 of certain diseases may cause the arteries to contract and 

 the heart to beat with great force and rapidity. Then the 

 blood cells may move so quickly that they have no time to 

 take up oxygen from the lungs. Neither rest nor violent 

 inspiratory efforts will relieve the resulting shortness of 

 breath, but more oxygen may reach the blood cells if it 

 is inhaled in a pure form. 



If there is an obstruction to the entrance of air into the 

 lungs, more oxygen may pass the obstruction if it is inhaled in 

 an undiluted form. When the larynx or trachea is obstructed 

 by a membrane in diphtheria, or when the small bronchi are 

 rilled with mucus, as in bronchitis and pneumonia, then the 

 inhalation of pure oxygen may be of great benefit. 



363. Asphyxia. When the breath is held, a feeling of 

 discomfort comes on in about half a minute, which soon 

 {becomes great distress. If a person is prevented from 

 taking a breath, he will become unconscious in a few 

 seconds, but will make great inspiratory efforts for a 

 minute or more. There will be convulsions, and the face 

 will turn purple, for all the blood is venous. Death will 

 take place in less than five minutes. This is called 

 asphyxia. At any time before death actually takes place 

 life can be restored by artificial respiration. 



