Cerebral Autoregulation: A Target for Improving Neurological Outcomes in Extracorporeal Life Support

Abstract

Despite improvements in survival after illnesses requiring extracorporeal life support, cerebral injury continues to hinder successful outcomes. Cerebral autoregulation (CA) is an innate protective mechanism that maintains constant cerebral blood flow in the face of varying systemic blood pressure. However, it is impaired in certain disease states and, potentially, following initiation of extracorporeal circulatory support. In this review, we first discuss patient-related factors pertaining to venovenous and venoarterial extracorporeal membrane oxygenation (ECMO) and their potential role in CA impairment. Next, we examine factors intrinsic to ECMO that may affect CA, such as cannulation, changes in pulsatility, the inflammatory and adaptive immune response, intracranial hemorrhage, and ischemic stroke, in addition to ECMO management factors, such as oxygenation, ventilation, flow rates, and blood pressure management. We highlight potential mechanisms that lead to disruption of CA in both pediatric and adult populations, the challenges of measuring CA in these patients, and potential associations with neurological outcome. Altogether, we discuss individualized CA monitoring as a potential target for improving neurological outcomes in extracorporeal life support.

Keywords: Cardiopulmonary resuscitation; Cerebral hemorrhage; Cerebrovascular circulation; Extracorporeal membrane oxygenation; Intracranial pressure; Stroke.

Fig. 1

Summary of potential factors contributing to CA disruption in extracorporeal life support. Created with BioRender.com. Ach acetylcholine, CA cerebral autoregulation, CBF cerebral blood flow, CPP cerebral perfusion pressure, ECMO extracorporeal membrane oxygenation, ICP intracranial pressure, MAP mean arterial pressure, NO nitric oxide, PaO₂, partial pressure of oxygen; PEEP positive end-expiratory pressure, VA venoarterial, VV venovenous