Second by second patterns in cortical electroencephalograph and systolic blood pressure during Cheyne-Stokes

Little is known about how arousal develops during the ventilatory phase of Cheyne-Stokes breathing. This study employs neural network analysis of elec troencephalograms (EEGs) to describe these changes and relate them to chang es in systolic blood pressure, which is probably a subcortical marker of ar ousal. Six patients with Cheyne-Stokes respiration (apnoea/hypopnoea index 32-69 h (-1)) caused by stable chronic heart failure underwent polysomnography incl uding arterial beat-to-beat systolic blood pressure determination. Periods of 15 sequential apnoeas during nonrapid eye movement steep were identified for each subject, For each apnoea, the EEG was examined second-by-second u sing neural net analysis from 28 s before to 28 s after apnoea termination first return of oronasal airflow, and this was compared with the systolic b lood pressure pattern. During the apnoeic phase, sleep deepened progressively, Arousal started to develop at or just before apnoea termination and progresses through the bre athing phase. The rise and fall in the s,systolic blood pressure closely fo llowed the rise and fall in electroencephalographic sleep depth. In conclusion, during Cheyne-Stokes breathing, cortical elechroencephalogra phic arousal begins at or just before the resumption of breathing. Cortical electroencephalographic steep depth changes are closely mirrored by change s in articial sl stolic blood pressure, suggesting that the state changes i n the cortical and basal brain structures may be synchronous.