P.031 The effect of burst suppression on cerebral blood flow and autoregulation in animals and humans - a systematic review

Abstract

Background: Burst suppression (BS) is an EEG pattern in which there are isoelectric periods interspersed with bursts of cortical activity. Targeting BS through anesthetic administration is used as a tool in the neuro-ICU but its relationship with cerebral blood flow (CBF) and cerebral autoregulation (CA) is unclear. We performed a systematic review investigating the effect of BS on CBF and CA in animals and humans. Methods: We searched MEDLINE, BIOSIS, EMBASE, SCOPUS, and Cochrane library from inception to July 2022. The data that were collected included study population, methods to induce and measure BS, and the effect on CBF and CA. Results: In total 45 animal and 26 human studies were included in the final review. In almost all the studies, BS was induced using an anaesthetic. In most of the animal and human studies, BS was associated with a decrease in CBF and cerebral metabolism, even if the mean arterial pressure remained constant. The effect on CA during periods of stress (hypercapnia, hypothermia, etc.) was variable. Conclusions: BS is associated with a reduction in cerebral metabolic demand and CBF, which may explain its usefulness in patients with brain injury. More evidence is needed to elucidate the connection between BS and CA.