Perioperative Changes of Cerebrovascular Autoregulation and Association With Cognitive Function

Cerebral blood flow is tightly regulated to ensure constant cerebral perfusion independently from systemic blood pressure fluctuations. This mechanism is termed cerebrovascular autoregulation and preserves adequate cerebral perfusion in a range between 50 and 150 mmHg of cerebral perfusion pressure. Upper and lower autoregulatory limits may vary individually. Beyond the autoregulatory range the protective autoregulatory response is lost, facilitating cerebral ischemia or hyperemia. The cerebrovascular response may be altered during general anesthesia, through direct effects of anesthetic agents on the vascular tone, changes of arterial partial pressure of carbon dioxide or the administration of vasoactive substances. The association of perioperative impairment of cerebral autoregulation and postoperative cognitive function has been discussed controversially.