Cerebrovascular Regulation and Sleep Apnea

Abstract

The brain relies on a constant blood flow to match nutrient delivery with the local metabolic demands. Cerebral blood flow (CBF) autoregulation is particularly important under hypoxic conditions such as obstructive sleep apnea (OSA) to prevent brain hypoxia. We aim to give a brief overview of cerebral blood flow regulation and evaluate the current evidence for cerebrovascular sensitivity to hypoxia, the capacity of cerebral arteries to respond to reduced oxygen supply during normal sleep and OSA. In clinical conditions such as intermittent hypoxia as well as untreated OSA, cerebrovascular system becomes less reactive to CO2 and impaired autoregulation, and makes the brain more susceptible to ischemic stroke. Results from studies in patients with OSA indicate worse clinical outcome including higher chance of cerebrovascular events, impaired functional capacity and cognition. Early treatment of OSA with continuous positive airway pressure (CPAP), resulting in reversal of cerebral autoregulation.