Goodson Carrie M, Rosenblatt Kathryn, Rivera-Lara Lucia, Nyquist Paul, Hogue Charles W
1 Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
J Intensive Care Med. 2018 Feb;33(2):63-73. doi: 10.1177/0885066616673973. Epub 2016 Oct 25.
Cerebral blood flow (CBF) autoregulation maintains consistent blood flow across a range of blood pressures (BPs). Sepsis is a common cause of systemic hypotension and cerebral dysfunction. Guidelines for BP management in sepsis are based on historical concepts of CBF autoregulation that have now evolved with the availability of more precise technology for its measurement. In this article, we provide a narrative review of methods of monitoring CBF autoregulation, the cerebral effects of sepsis, and the current knowledge of CBF autoregulation in sepsis. Current guidelines for BP management in sepsis are based on a goal of maintaining mean arterial pressure (MAP) above the lower limit of CBF autoregulation. Bedside tools are now available to monitor CBF autoregulation continuously. These data reveal that individual BP goals determined from CBF autoregulation monitoring are more variable than previously expected. In patients undergoing cardiac surgery with cardiopulmonary bypass, for example, the lower limit of autoregulation varied between a MAP of 40 to 90 mm Hg. Studies of CBF autoregulation in sepsis suggest patients frequently manifest impaired CBF autoregulation, possibly a result of BP below the lower limit of autoregulation, particularly in early sepsis or with sepsis-associated encephalopathy. This suggests that the present consensus guidelines for BP management in sepsis may expose some patients to both cerebral hypoperfusion and cerebral hyperperfusion, potentially resulting in damage to brain parenchyma. The future use of novel techniques to study and clinically monitor CBF autoregulation could provide insight into the cerebral pathophysiology of sepsis and offer more precise treatments that may improve functional and cognitive outcomes for survivors of sepsis.
脑血流量（CBF）自动调节可在一定血压（BP）范围内维持血流稳定。脓毒症是系统性低血压和脑功能障碍的常见原因。脓毒症血压管理指南基于CBF自动调节的历史概念制定，而随着测量技术更加精确，这些概念如今也在不断演变。在本文中，我们对监测CBF自动调节的方法、脓毒症对脑的影响以及脓毒症中CBF自动调节的现有知识进行了叙述性综述。当前脓毒症血压管理指南的目标是将平均动脉压（MAP）维持在CBF自动调节下限之上。现在有床旁工具可用于持续监测CBF自动调节。这些数据显示，通过CBF自动调节监测确定的个体血压目标比之前预期的更具变异性。例如，在接受体外循环心脏手术的患者中，自动调节下限在MAP 40至90 mmHg之间变化。脓毒症中CBF自动调节的研究表明，患者常表现出CBF自动调节受损，这可能是由于血压低于自动调节下限所致，尤其是在脓毒症早期或伴有脓毒症相关性脑病时。这表明目前脓毒症血压管理的共识指南可能会使一些患者面临脑灌注不足和脑灌注过多的风险，从而可能导致脑实质损伤。未来使用新技术研究和临床监测CBF自动调节，可能会深入了解脓毒症的脑病理生理学，并提供更精确的治疗方法，从而改善脓毒症幸存者的功能和认知结局。
