I30 RESPIRATION 



With anoxaemia, as already explained, the respiratory center 

 becomes very easily susceptible of fatigue, as manifested by di- 

 minishing depth of the breathing. It is now well known that in 

 the resuscitation of persons who have been nearly asphyxiated by 

 drowning, asphyxiating atmospheres, etc., the most effective 

 remedy is artificial respiration. This is because the respiratory 

 center has completely or almost completely failed or become 

 "fatigued," and the patient would die if this condition were not 

 compensated for by artificial respiration. Respiration seems almost 

 always to fail before the heart fails. The respiratory center may 

 also take a long time to recover sufficiently to be able, without 

 artificial aid, to keep the patient alive. For this reason it may be 

 necessary to prolong the artificial respiration for hours. 



Diminishing depth with increasing rate of respiration is always 

 a sign of the onset of fatigue of the breathing; and when the 

 depth continues to diminish without compensation from increased 

 rate the condition rapidly becomes dangerous, as will be shown 

 in Chapter VII, since secondary anoxaemia develops. In a person 

 dying quietly the diminishing depth can be observed until the 

 resulting anoxaemia ends in death. The immediate cause of death 

 seems to be failure of the respiratory center. When death from 

 anoxaemia occurs at very high altitudes (as, for instance, in the 

 case referred to in Chapter XII, of the balloonists, Tissandier and 

 Croce Spinelli) it is evidently failure of the respiratory center 

 which precipitates the anoxaemia, thus making the conditions 

 so very dangerous; and the same remark applies to asphyxiation 

 in atmospheres containing a low percentage of oxygen in mines, 

 wells, etc. In CO poisoning, as will be explained in Chapter VII, 

 there is not so much danger from this cause, so that extreme anox- 

 aemia may exist for a long time without death occurring. 



After the respiratory center has been over-fatigued in conse- 

 quence of anoxaemia, the effects may not pass off for a very long 

 period. The breathing on exertion, or even during rest, is ab- 

 normally shallow ; and the peculiar group of symptoms observed 

 in the neurasthenic condition so familiar during the war, and al- 

 ready referred to in Chapter III, is observed. This condition may 

 remain for months after severe anoxaemia, and is often mistaken 

 for organic heart injury. 



In considering the effects of anoxaemia a factor comes in which 

 must always be borne in mind — namely that of adaptation or ac- 

 climatization. This may act in two different ways. In the first 

 place adaptation may bring it about that the anoxaemia which 



