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Intracranial hemodynamics in sleep apnea
A Q Fischer1, B A Chaudhary, M A Taormina
1International Institute of Neurosonology, University Hospital, Augusta, Georgia.
Chest
|November 1, 1992
Summary
Severe sleep apnea syndrome (SAS) is linked to reduced cerebral blood flow velocities. Transcranial Doppler sonography reveals lower blood flow in SAS patients, suggesting its utility in evaluating this condition.
Area of Science:
- Neurology
- Cardiovascular Science
- Sleep Medicine
Background:
- Sleep apnea syndrome (SAS) is associated with intracranial pressure changes and impaired cerebral perfusion.
- Previous studies were limited by the lack of reliable noninvasive methods to assess cerebral blood flow.
Purpose of the Study:
- To investigate cerebral blood flow velocities in patients with severe SAS compared to healthy controls.
- To evaluate the utility of transcranial Doppler sonography in assessing cerebral hemodynamics in SAS.
Main Methods:
- Utilized transcranial Doppler sonography to measure systolic, diastolic, and mean cerebral blood flow velocities of the middle cerebral artery.
- Included 23 participants: 12 with severe SAS and 11 controls.
- Measurements were taken before sleep, during NREM and REM sleep, and upon awakening.
Main Results:
- Cerebral blood flow velocities (systolic, diastolic, mean) were significantly decreased in SAS patients compared to controls.
- Mean and systolic velocities showed significant reductions (p = 0.033 and p = 0.005, respectively).
- SAS patients exhibited higher end-tidal CO2 levels (47.3 mm Hg vs. 41.8 mm Hg), and velocity reduction became more pronounced after CO2 normalization.
Conclusions:
- Patients with severe SAS demonstrate reduced cerebral blood flow velocities.
- Transcranial Doppler sonography is a potentially valuable noninvasive tool for evaluating cerebral hemodynamics in SAS.