Brain hemodynamics in septic patients.

Brain dysfunction is a frequent complication of sepsis. Most likely, sepsis-associated brain dysfunction (SABD) results from the interaction between multiple factors: neurodegeneration due to microglial activation, altered neurotransmission, neuroinflammation and impairment of cerebral macro- and microcirculation. Altered brain perfusion might results from several mechanism: global or regional alterations in cerebral blood flow (CBF); reduced cerebral perfusion pressure - which is the driving force propelling blood through cerebral blood vessels - due to systemic hypotension; global or regional vasoconstriction; dysfunction of the intrinsic regulatory mechanisms of CBF, such as cerebral autoregulation and cerebrovascular reactivity; endothelial and blood-brain barrier dysfunction; autonomic nervous system dysfunction and metabolic uncoupling. Disorders of brain perfusion and CBF regulation are frequently observed in humans with sepsis, and intracranial hemodynamics monitoring can potentially be useful in clinical management of septic patients. The aim of this review is to provide an update of the current knowledge on alterations in brain hemodynamics associated with sepsis, along with physiological and methodological considerations intended to help the reader navigate the diverse results from published literature and a practical guide to apply non-invasive intracranial hemodynamics monitoring to septic patients in clinical practice.