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Cerebral perfusion during sleep-disordered breathing
Hajak1, Klingelhöfer, Schulz-Varszegi
1Department of Psychiatry, University of Göttingen, Germany.
Journal of Sleep Research
|June 1, 1995
Summary
Sleep apnoea syndrome (SAS) disrupts cerebral blood flow, increasing stroke risk. This study found heightened CO2 reactivity during sleep in SAS patients, potentially causing critical reductions in brain perfusion.
Area of Science:
- Neurology
- Sleep Medicine
- Cardiovascular Physiology
Background:
- Snoring, a key symptom of sleep apnoea syndrome (SAS), is linked to sleep-related strokes.
- Apnoeic episodes cause hypoxaemia and hypercapnia, affecting cerebral blood flow regulation.
- CO2 is a primary regulator of cerebral blood flow, suggesting potential perfusion changes in SAS.
Purpose of the Study:
- To investigate cerebral haemodynamics during sleep in patients with SAS.
- To assess the relationship between sleep stages, apnoea, and cerebral blood flow velocity (CBFV).
- To evaluate CO2 reactivity and its impact on cerebral perfusion in SAS.
Main Methods:
- Utilized a modified Doppler ultrasonography system for continuous CBFV recording.
- Simultaneously performed polysomnography, blood pressure monitoring, and end-expiratory CO2 measurement.
- Measured CBFV in the right middle cerebral artery in 10 SAS patients.
Main Results:
- CBFV exhibited a nocturnal pattern: decreasing in NREM sleep, increasing in REM sleep.
- Apnoeic episodes led to dramatic CBFV increases, especially during REM sleep.
- CO2 reactivity and CBFV changes related to apnoea duration were significantly higher during sleep in SAS patients.
Conclusions:
- SAS patients show altered CBFV dynamics during sleep, indicating uncoupling between cerebral activity and perfusion.
- Increased CO2 reactivity during sleep suggests hypersensitive vasoactive receptors or autonomic control disturbances.
- The interplay of reduced perfusion, sleep patterns, and apnoeic haemodynamics may critically lower cerebral perfusion in SAS.