The definition of "Cheyne-Stokes rhythms".

The review of the literature on Cheyne-Stokes respiratory periods reveals enormous variation of the opinions expressed. The original description concerned periodicity characterized by rhythmic changes of respiratory phases and respiratory pauses in a relation of 60 : 15 seconds. In the respiratory phase there were 30 respirations of increasing depths and frequency at the beginning of the phase and decreasing depths and frequency at the end of the phase. Literature data about Cheyne-Stokes respiration comprise a multiplicity of all rhythymic forms. The duration of respiratory cycles varies between 12 and 130 seconds. The relation of the respiratory phase and respiratory pause between 6 : 4 or 75 : 70 seconds, and the number of breaths between 3 and 30 during one respiratory phase. Cheyne-Stokes periods were observed in health subjects as well as in patients with neurological, neurosurgical, cardiac, pulmonary and paediatric diseases. Cheyne-Stokes periods were explained as sequel of prolongation of circulation time between pulmonary alveoli and respiratory centre, through increased sensitivity of the respiratory centre to CO2, diminished sensitivity of the respiratory centre to CO2 and O2-deficit, local blood flow disturbances, section of pathways in the brain stem with disinhibition of basic rhythms, brain immaturity, alterations of consciousness, and respiratory obstructions. Rhythmic changes of the heart beat, of excitability of the heart muscle, of blood pressure, of EEG and of neurological and mental signs were observed. In spite of numerous observations detailed analysis of the respiratory cycle was performed in only a few cases. Major studies are lacking.