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Assessing Cerebral Autoregulation via Oscillatory Lower Body Negative Pressure and Projection Pursuit Regression
Published on: December 10, 2014
Impaired cerebral autoregulation in obstructive sleep apnea
Fred Urbano1, Francoise Roux, Joseph Schindler
1Yale Center for Sleep Medicine, Department of Medicine, Yale University School of Medicine New Haven, Connecticut, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|October 18, 2008
Summary
Obstructive sleep apnea (OSA) impairs cerebral blood flow and delays cerebrovascular responses, increasing stroke risk. This study found reduced cerebral artery blood flow velocity and impaired autoregulation in OSA patients.
Area of Science:
- Neurology
- Sleep Medicine
- Vascular Physiology
Background:
- Obstructive sleep apnea (OSA) is linked to increased stroke risk, independent of traditional factors.
- Mechanisms remain unclear, but OSA involves blood pressure surges, hypercapnia, and cerebral blood flow fluctuations.
- These events may compromise cerebral circulation and autoregulation.
Purpose of the Study:
- To investigate cerebral autoregulation in patients with OSA compared to controls.
- To determine if impaired autoregulation contributes to the heightened risk of cerebral ischemia and stroke in OSA.
Main Methods:
- Compared cerebral autoregulation in 22 OSA patients and 26 controls using transcranial Doppler ultrasound and photoplethysmography.
- Measured cerebral artery blood flow velocity (CBFV) and blood pressure during orthostatic stress and CO2 inhalation.
- Assessed cerebral vascular conductance and reactivity.
Main Results:
- OSA patients exhibited significantly lower mean CBFV (48 vs. 55 cm/s) compared to controls.
- The OSA group showed a reduced rate of cerebrovascular conductance recovery following blood pressure drops.
- No significant difference in cerebrovascular vasodilatation response to CO2 was observed between groups.
Conclusions:
- Patients with OSA have reduced baseline cerebral blood flow velocity.
- OSA is associated with delayed cerebrovascular compensatory responses to blood pressure changes.
- These circulatory dysfunctions may elevate the risk of cerebral ischemia during obstructive apnea events.
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