Studies on Cheyne-stokes Respiration.

Cheyne-Stokes respiration is characterized by rhythmic changes in breathing in which periods of respiratory pause alternate with periods of slowly increasing and decreasing respiratory activity. It may be accompanied by phasic variations in the functions of the heart, nervous system and other organs, and has more recently been found to be associated with periodic variation in the concentration of the gases in the blood. It occurs as a symptom in diseases of the heart and kidneys especially, in meningitis and in encephalitis, and in certain intoxications such as morphine poisoning and oxygen lack. The development of this type of breathing has been ascribed to many causes-disturbances in the gaseous exchange in the lungs, of the circulation, of the activity of the respiratory and vasomotor centers and to so-called sub-cortical influences. Objections to all these hypotheses have been entered with the result that no satisfactory understanding of the subject has been attained. It is of value, therefore, to record further observations of Cheyne-Stokes respiration and its attendant or resultant phenomena. The phenomenon concerning which it seems now important to accumulate more experience, is the behavior of the gases, carbon dioxide and oxygen, in the blood under the circumstances which attend this type of respiration. For this purpose, samples of arterial blood taken from patients exhibiting this abnormality were studied. A few analyses of arterial blood have already been reported by Gollwitzer-Meier (1), Uhlenbruck (2), and Resnik and Lathrop (3). Their studies show that variations in the concentration of the gases in the blood do occur during different phases of respiration I and that at some point during the respiratory cycle, oxygen saturation of the blood usually reaches normal limits. The average carbon dioxide content in the blood is reported in some cases to be increased, in others decreased, and in others normal. In former studies only one or two samples of blood were, however, taken; but in order to ascertain the extent of the variation in the concentration of the gases in the blood during a cycle of Cheyne-Stokes respiration it is