142 RESPIRATION 



Ordinary clinical Cheyne-Stokes breathing is evidently a symp- 

 tom of anoxaemia due often to the shallow breathing which char- 

 acterizes a failing respiratory center. This failure may be that of 

 approaching death, since the anoxaemia itself tends to hasten the 

 failure of the center, as already explained in Chapter VI. There 

 is thus a vicious circle which, unless broken in some way, must end 

 in death from anoxaemia, just as in the case of an airman at a 

 dangerously high altitude. The color of the lips, in conjunction 

 with the diminishing depth of the breathing, points clearly to 

 what is happening. 



It is now evident that the anoxaemia so often present in disease, 

 but so seldom recognized as such, is due in a large number of 

 cases to the shallow breathing characteristic of a damaged or 

 "fatigued" respiratory center, whatever the original cause of the 

 damage or fatigue may be. It is also evident that frequency of 

 breathing has assumed a significance which it did not previously 

 possess, since frequency is very often an index of shallowness of 

 breathing, damage to the respiratory center, and consequently 

 impending danger from anoxaemia. The frequent and shallow 

 breathing in surgical shock, or in various forms of influenza and 

 pneumonic conditions, or as it may occur in many other forms of 

 disease, is a symptom of which the possible deadly import will be 

 evident enough to those who have read the preceding chapter in 

 connection with what has just been said. In this connection I 

 should like also to emphasize the fact that, as fully explained in 

 the last chapter, it is unsafe to judge of the degree of anoxaemia 

 by the degree of cyanosis. The anoxaemia is, and must be, ac- 

 companied by alkalosis, so that the oxyhaemoglobin holds on more 

 tightly to its oxygen, and this alkalosis may become extreme with^ 

 very shallow and rapid breathing. 



Chronic fatigue or failure of the respiratory center is seen in^ 

 neurasthenia and various other forms of disease; but failure of 

 the respiratory center may also occur in acute and sudden attacks, 

 which are often associated, either primarily or secondarily, with 

 anginal pain. The patient may feel that he cannot expand his 

 chest to breathe, just as if it were mechanically constricted; and] 

 he rapidly develops asphyxial symptoms, with very frequent and' 

 shallow breathing. In reality, apparently, he is in the grip of the 

 Hering-Breuer reflex, which, as explained in Chapter III, assumes 

 exaggerated influence, owing to the failure of the respiratory 

 center. These attacks, though they usually pass ofi", are sometimes 

 very dangerous; and many sudden deaths appear to be due to 



