Zauner Alois, Daugherty Wilson P, Bullock M Ross, Warner David S
Division of Neurosurgery, Medical College of Virginia, USA.
Neurosurgery. 2002 Aug;51(2):289-301; discussion 302.
CONTINUOUS OXYGEN DELIVERY and CO(2) clearance are paramount in the maintenance of normal brain function and tissue integrity. Under normal conditions, aerobic metabolism is the major source of energy in the brain, but this system may be compromised by the interruption of substrate delivery and disturbances in cerebral metabolism. These disruptions are major factors contributing to ischemic and hypoxic brain damage resulting from traumatic brain injury, stroke, and subarachnoid hemorrhage. There is evidence that mitochondrial function also is reduced after injury. Furthermore, early impairment of cerebral blood flow in patients with severe injury correlates with poor tissue oxygenation and may be an important parameter in secondary damage. Recent advances in brain tissue monitoring in the intensive care unit and operating room have made it possible to continuously measure tissue oxygen tension and temperature, as well as certain aspects of brain metabolism and neurochemistry. Therefore, it is important to understand the physiological process and the pathophysiology produced by these events. This is Part I of a two-part review that analyzes the physiology of cerebral oxygenation and metabolism as well as some of the pathological mechanisms involved in ischemic and traumatic brain injuries. Brain tissue monitoring techniques will be examined in the second article of this two-part series. To understand cerebral oxygenation, it is important to understand cerebral blood flow, energy production, ischemia, acidosis, generation of reactive oxygen species, and mitochondrial failure. These issues provide the basis of knowledge regarding brain bioenergetics and are important topics to understand when developing new approaches to patient care.
持续输氧和清除二氧化碳对于维持正常脑功能和组织完整性至关重要。在正常情况下，有氧代谢是大脑能量的主要来源，但该系统可能会因底物供应中断和脑代谢紊乱而受损。这些干扰是导致创伤性脑损伤、中风和蛛网膜下腔出血所致缺血性和缺氧性脑损伤的主要因素。有证据表明，损伤后线粒体功能也会降低。此外，重伤患者早期脑血流受损与组织氧合不良相关，可能是继发性损伤的一个重要参数。重症监护病房和手术室脑组织监测的最新进展使得连续测量组织氧张力、温度以及脑代谢和神经化学的某些方面成为可能。因此，了解这些事件所产生的生理过程和病理生理学很重要。这是一篇分两部分的综述的第一部分，分析了脑氧合和代谢的生理学以及缺血性和创伤性脑损伤中涉及的一些病理机制。脑组织监测技术将在本系列的第二篇文章中进行探讨。为了理解脑氧合，了解脑血流、能量产生、缺血、酸中毒、活性氧的产生以及线粒体功能衰竭很重要。这些问题为有关脑生物能学的知识提供了基础，并且是在开发新的患者护理方法时需要理解的重要主题。
