Chest
clinical investigationsSleep Apnea Syndrome and Cerebral Hemodynamics
Section snippets
Subjects
Subjects were recruited for the investigation after the study had been approved by the local ethics committee. A total of 16 patients with SAS and 16 healthy individuals participated in the study after giving their informed consent. Six patients and six healthy subjects were excluded from data analysis because of movement artifacts with subsequent probe dislocation. Recordings of the right middle cerebral artery (MCA) of 10 patients with SAS (mean age, 37 years) and 10 control subjects (mean
Results
Patients and control subjects showed a gradual reduction in MFV, as compared with wake values, during deepening NREM sleep in the first sleep cycle. Even intermittent increases in depth of sleep did not affect the continuously decreasing mean level of MFV. Despite a subsequent rise in depth of sleep from sleep stage 4 to sleep stage 2 preceding the first REM period, MFV continued decreasing and tended to be lower in sleep stage 2 than in the preceding deep sleep phase (Fig 1). From the first to
Discussion
Computer−assisted TCD offered the unique opportunity to record cerebral hemodynamics on−line, over a time course of seconds, and continuously throughout the entire sleep period in combination with polysomnography. Data presented in this study reveal two main aspects: (1) that the CBFV in patients with SAS is related to the dynamic process of alternating sleep stages and (2) that changes of CBFV not only depend on chemical (Pco2) but also on neuronal (arousal) influences during sleep apnea
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Presented in part at the “Third International Marburg Symposium on Cardiocirculatory Function during Sleep,” Germany, August 31-September 2, 1994.
Manuscript received July 26, 1995; revision accepted April 12, 1996.